Dynamics Of The Disease
Parvovirus is an extremely tough and resistant bug. The virus lives for long periods of time on floors, food containers and other household objects. Rugs are particularly difficult to sanitize. It is thought that household vermin such as cockroaches move the virus from place to place. The virus is both resistant to phenolic disinfectants and to heat. It can be inactivated, however, with ordinary household bleach used at a concentration of one part bleach to twenty parts water. Exposure to sunshine also kills the virus. For the bleach solution to work, any caked organic material must first be removed by washing.
Although it takes one or two weeks for the dog to develop signs of disease, the virus is shed in the feces from the third day of exposure onward. This means that dogs that appear healthy can already be shedding the virus and contaminating the home.
The Symptoms of Parvo
Parvovirus disease is remarkable in that symptoms can vary from none at all to a fatal disease. Four factors govern the severity of the disease: age at exposure, the size of the virus dose, the presence of maternal antibody, and the breed of dog involved.
Dogs receive transient maternal antibody from their mothers through their first milk or colostrum. This antibody gives the puppy resistance to the disease. Puppies that are housed in a parvo-filled environment rarely break with the disease until they reach 14-20 weeks of age. At that time their mother’s immunity no longer protects them and they may die of the disease.
Dogs over six month of age develop natural resistance to the effects of parvovirus. Many of these dogs show only transient diarrhea. By the time the dog reaches one or two years of age the disease can be so mild that it passes unnoticed by the owners.
For unknown reasons, Doberman Pinschers, Rottweilers and Pit Bull Terriers become more ill with this disease than other breeds.
The most common form of parvovirus infection is a sudden (acute) inflammation of the small intestine or enteritis. This is characterized by depression, vomiting, diarrhea and profound dehydration. Bloody stools and a drop in white blood cell numbers are common. Some puppies die as soon as diarrhea occurs but many linger on for 4-6 days. Those that survive eight days usually recover. The lack of white blood cells and ulceration of the lining of the small intestine lead to secondary bacterial infections. There are many other virus and bacteria that can cause bloody diarrhea in dogs. This leads to misdiagnosis where not all cases of “Parvo” in puppies and adults are actually due to this virus.
Although symptoms can be very suggestive of Parvo, true diagnosis requires an antibody test that detects the actual parvovirus in stool samples. The test is an ELISA test or enzyme-linked immunosorbent assay. Early in the disease, this test can be negative. Virus isolation is possible but the procedure is quite expensive and rarely done. In practice, the presence of an acute hemorrhagic diarrhea is usually all that is required for a tentative diagnosis of parvovirus.
Treatment of parvovirus is directed at correcting the life-threatening dehydration that accompanies the diarrhea with intravenous fluids (lactated ringers solution with bicarbonate). Ten to forty milliliters per pound is given initially and then a slow intravenous drip may stabilize these dogs. Once the initial dehydration is corrected, maintenance fluids can also be given subcutaneously. We also give medicines that relax intestinal spasms such as metoclopramide (Reglan, 0.1-0.25mg/lb three or four times a day) and trimethobenzamide (Tigan, 1.5mg/lb three times a day). Besides this, the dogs are placed on antibiotics to prevent secondary bacterial infection through the damaged small intestine (cephalothin, Keflin @ 5-15mg/pound given four times a day intramuscularly or intravenously). Early in the disease dogs may run a short period of fever. But puppies’ temperatures often drop to subnormal a few days later. These dogs need additional sources of heat. It helps to sit with the dog, pet it and encourage its will to live. Many of the younger dogs have hookworm infestations that make the parvovirus disease more severe. As soon as these dogs can hold down liquids, I worm them with pyrantel pamoate (Strongid, Nemex, 2.5mg/pound).
Some veterinarians give the dogs small doses of butorphanol tartrate (Torbugesic 0.05-0.1mg/pound intramuscularly) to relieve the severe abdominal pain that accompanies this disease.
Dogs and puppies that begin to accept small portions of food invariably are on the road to recovery. Wagging their tail is also a good sign. Despite all my efforts, many young dogs with parvo do not survive.
Immunity To The Disease
Recovered dogs are probably immune for life. Because of the strong immunity that follows infection, carrier dogs do not exist.
Many excellent brands of vaccine are on the market. Most contain living, attenuated (weakened) parvovirus. All products are safe and produce good immunity when the last injection is given at 18 weeks of age. When a vaccine fails it is usually because it was given to a puppy before enough passive maternal antibody was gone from its blood stream. At six weeks of age one quarter of puppies can be immunized successfully. At nine weeks of age forty percent of puppies can be immunized successfully. By sixteen weeks sixty percent of puppies can be immunized successfully and by eighteen weeks ninety-five percent of puppies can be immunized successfully. Some newer vaccines called high titer-low passage vaccines are successful in immunizing puppies at an earlier age (12wks). Antibody level testing is quite expensive. Rather than measuring antibody levels in the blood of puppies in order to choose the right age to administer the vaccine, we give a series of shots designed to successfully immunize most puppies before they come in contact with the virus while susceptible.
I give parvo vaccine at 12, 14 and 18 weeks of age. When I see puppies at 9 weeks of age I may also vaccinate them. This “puppy shot series” causes us to vaccinate some puppies that are not ready to respond to the vaccine and to re-vaccinate some puppies that are already immune to the disease. It is also possible for some susceptible puppies to “slip through” these periodic vaccinations and be susceptible to parvo for a period of days. These are the unfortunate dogs that develop parvo despite vaccination.
Parvovirus is still a major threat to dogs in the United States and a common cause of mortality in puppies. Due to the resistance of the virus to antiseptics, heat and drying it is impossible to manage a kennel to be 100% safe from this disease. No matter what puppy vaccination schedule is used, there will be a window of susceptibility when puppies are at risk of disease if exposure occurs. Rapid veterinary care can save many infected dogs but some will die from the disease despite excellent care.
As the name implies, parvovirus is a viral illness.
Effective vaccination is possible.
Parvovirus is predominantly a disease of young puppies between 6 weeks and 6 months of age.
Without treatment approximately 80% of affected puppies will die.
With proper treatment approximately 85% of affected puppies will live.
The virus may persist in the environment for up to 5 months.
Infection generally follows exposure to infected feces.
The incubation period for the illness is 4 to 14 days.
The major clinical signs are vomiting and diarrhea. The diarrhea is usually yellow to yellow gray at first but quickly becomes blood tinged or dark red in most cases
Canine parvovirus is a DNA virus. There are two major strains, canine parvovirus 1 (CPV-1)and canine parvovirus 2 (CPV-2). The CPV-2 strain has mutated several times and there are CPV-2a, CPV-2b and CPV-2c strains. The CPV2-a to c strains have the ability to infect both dogs and cats but clinically significant infections of domestic cats have not been reported up to this time.
The virus is shed in the feces of infected dogs. It is passed to another dog through the nasal or oral tissues after exposure. The virus begins to be shed about 4 days after exposure. There may not be clinical signs at the time that shedding starts.
Parvovirus attacks rapidly dividing cells. In growing animals the most rapid cell division occurs in the lining of the gastrointestinal tract. Puppies who have other infections with worms, bacteria or intestinal viruses seem to be affected more severely than puppies who do not have these problems. Another site of rapid cell division is the myocardium, or heart muscle tissue. Very young puppies, usually less than 8 weeks of age, that are infected with parvovirus may suffer severe myocardial problems and die as a result of them. When this happens it may affect the entire litter of puppies.
There is a temptation to blame almost any case of vomiting and diarrhea in a young puppy on parvovirus but it is important to keep in mind there are many other causes of these symptoms. It can be hard to definitively diagnose parvovirus in a clinical setting. Most puppies with parvovirus seem very ill. They are usually noticeably depressed. There is usually vomiting and severe diarrhea. White blood cell counts are suppressed, especially the neutrophils. There are tests for parvovirus but false positives can occur within 5 to 12 days of vaccination and false negative tests occur, as well. A combination of suspected clinical symptoms, a positive parvovirus test and low white blood cell count comes close to ensuring a proper diagnosis. If two out of three of these criteria are present it is likely but not certain that parvovirus is present.
Adult dogs that become infected with parvovirus generally have no clinical signs or perhaps transient diarrhea. While these dogs may shed the virus they are not severely affected by it. It is rare to see confirmed clinically significant parvovirus in a dog over 18 months of age.
Treatment for parvovirus is supportive. There is no direct anti-viral medication for this disease. Treatment efforts are focused on keeping puppies hydrated, making sure that their electrolyte balances are relatively normal and preventing secondary infections that occur due to the tissue damage and low white blood cell counts. There are a number of things that can be helpful when treating parvovirus:
Antiemetic drugs - ondansetron, dolasetron and maropitant (Cerenia Rx)
Intravenous or subcutaneous fluid therapy
Broad spectrum antibiotics – note that this is an important part of treatment even though this is a viral illness!
Hyperimmune plasma or antiendotoxin sera (Septi-serum Rx)
Flunixin (Banamine Rx) may be beneficial if puppies become septicemic (have widespread bacterial infection)
If a puppy survives the first four days of treatment it is likely that it will survive parvovirus infection.
Vaccination and Prevention
Puppies receive protection from parvovirus in the colostrums, or first milk produced by their mothers. This protection is variable depending on whether the mother had antibodies against parvovirus and how much colostrums a puppy received in its first 24 hours of life. In some cases this protection is not conferred. This variability in maternal protection is the major reason a series of vaccinations is given to puppies. A starting date for vaccination is picked based on the puppy’s ability to respond to infection and the likely timing of exposure to the disease. In general the first vaccination in the puppy series is given between 6 and 8 weeks of age. Only a portion of puppies are capable of responding to this initial vaccine series but since it isn’t practical to determine in advance which puppies can respond, all are vaccinated. The puppies that need the protection get it and the rest do not benefit from the first vaccine. At least 2 weeks later and preferably 3 to 4 weeks later, a second vaccination is given. A larger percentage of puppies respond to this vaccine, but not all of them. The vaccination series is continued at 3 to 4 week intervals until it is likely that all puppies who can respond to vaccination have done so. The number of vaccinations in the series and the age at which the final puppy series vaccination is given will depend on the type of vaccine used, the breed of the puppy, the puppy’s lifestyle, the owner’s experiences and the veterinarian’s experiences with the disease.
Vaccines are produced by several vaccine manufacturers for prevention of parvovirus. Most of the currently available vaccines are high antigen vaccines which break through maternal antibody protection earlier than the the original parvovirus vaccines. These vaccines also provide protection in most puppies when given between 12 and 14 weeks of age. The older parvovirus vaccines had to be given until 16 or even 20 weeks of age to ensure maximum protection. Of the currently available vaccines still in use only the Vanguard ™ series of vaccines from Pfizer Animal Health ™ are the older type of vaccine (as of 2006, per “Infectious Diseases of the Dog and Cat” by Greene).
There is a period of time, between 2 and 3 weeks, when the parvovirus strains found in most infections can cause disease before there is a chance for vaccinations to work. At the present time there is no way to avoid this period. More frequent vaccination is not helpful and vaccinations given closer than two weeks apart may even impair immunity. For this reason, it is best to avoid exposure to potential sites of infection, such as dog parks, dog shows and kennels until after the last vaccine in the series. It is also important to remember that the veterinarian’s office is a potential site of contamination, especially the area outside the veterinary hospital. Puppies should be walked directly to the door and should be kept away from other puppies in the waiting room that appear to be ill. Veterinary hospitals and kennels try very hard to properly clean up after incidences of diarrhea and in areas in which exposure can occur but it is hard to do this perfectly.
Parvovirus is very hardy in the environment. If your house becomes contaminated by the virus clean any surfaces that can be cleaned with chlorine bleach diluted 1 oz of bleach to 32 oz of water. The disinfectant potassium peroxymonosulfate (Trifectant ™ or Virkon ™) is also effective. It is extremely hard to disinfect a yard. Realistically, if your yard has been potentially contaminated with parvovirus it would probably be best not to get a new puppy and expose it to the yard for at least six months and nine months would be better. Areas of the yard that are exposed to sunlight will require less time for the virus to die than areas of the yard that are shaded, moist and sandy. At the present time there is not a disinfectant product marketed for use in yards that has been proven to be effective against parvovirus.
Whether or not infection happens depends on the interaction of three things: Host Vitality (including immune experience/vaccination status), Virulence of the Virus (including how many viral particles the host is exposed to), and Environmental factors. Obviously these three aspects interplay somewhat (a stressful environment will reduce host vitality, a dry environment will reduce the number of viral particles etc.)
WHERE DOES VIRUS COME FROM?
Remember that this virus has been around for nearly 20 years, is very hard to disinfect away, and is shed in large numbers by infected dogs. This means that there is virus everywhere: on every carpet, on every floor, in every yard and park. Virus is shed for the first two weeks or less after infection in the stool of an infected dog but only a tiny portion of infected stool (which could be months old depending on the environmental temperature and humidity) is needed to infect a non-immune dog. Some dogs become what is called "subclinically infected" which means they do not appear particularly sick. These animals tend not to be confined since no one knows they are infected thus they can spread virus around a large area depending on where they leave their droppings.
WHY ONLY PUPPIES?
The most important factors in parvovirus infection seem to be the immune experience the host (dog) has had with the virus plus the number of viral particles the host is exposed to. Twenty years ago when the virus was new, all dogs young and old were susceptible but now, because the virus is present everywhere, all dogs, even the unvaccinated ones, have at least some immunological experience with this virus. Any exposure no matter how small is likely to generate some antibodies. Also, vaccination is a widespread process nowadays and it is likely that a dog has had at least one vaccine at some point. Will these antibodies be enough for protection? In general, the answer seems to be yes as infection in dogs over age one is somewhat unusual. It is important to realize, however, that this observation should not be taken to mean that adult dogs should not continue their vaccinations. Even though infection is somewhat unusual in adult dogs, adult dogs should still continue their vaccinations as this is a life threatening disease for which treatment is expensive and no chances should be taken.
When puppies are born, they are completely unable to make antibodies against any infectious invader. They would be totally unprotected except that nature has created a system to protect them. Their mother secretes a special milk for the first day or two after giving birth. This milk is called "colostrum." It contains all the antibodies that the mother dog has circulating in her own body and in this way, she gives her own immune experience to her off-spring. These antibodies protect the puppies until they wear off sometime in the first 4 months of life.
How much colostrum an individual puppy gets depends on its birth order and how strong a nurser it is; not all puppies get the same amount of antibodies. Every nine days the antibody levels possessed by the puppies drops by half. When the antibody level drops to a certain level, they no longer have enough antibody to protect them and if they are exposed to a large enough number of viral particles, they will get infected.
We recommend that puppies be restricted from public outdoor areas until their vaccination series is completed at age 16 weeks.
There is a good week or so period during which the puppy has no antibody protection leftover from its mother but still is not yet competent to respond to vaccination. This window is where even the most well cared for puppies get infected.
The virus enters the body through the mouth as the puppy cleans itself or eats food off the ground or floor. A minuscule amount of infected stool is all it takes.
There is a 3-7 day incubation period before the puppy seems obviously ill.
Upon entering the body, the virus seeks out the nearest rapidly dividing group of cells. The lymph nodes of the throat fits the bill and the virus sets up here first replicating to large numbers. After a couple of days, so much virus has been produced that significant amounts of virus have been released free into the bloodstream. Over the next 3-4 days, the virus seeks new organs containing the rapidly dividing cells it needs: the bone marrow and the delicate intestinal cells.
Within the bone marrow, the virus is responsible for destruction of young cells of the immune system. By killing these cells, it knocks out the body's best defense and ensures itself a reign of terror in the GI tract where its most devastating effects occur. All parvoviral infections are characterized by a drop in white blood cell count due to the bone marrow infection. Seeing this on a blood test may help "clinch" the diagnosis of parvoviral infection. Also, a veterinarian may choose to monitor white blood cell count or even attempt to artificially raise the white blood cell count in an infected puppy through treatment.
It is in the GI tract where the heaviest damage occurs. The normal intestine possesses little finger-like protrusions called "villi." Having these tiny fingers greatly increases the surface area available for the absorption of fluid and nutrients. To make the surface area available for absorption greater still, the villi possess "microvilli" which are microscopic protrusions. The cells of the villi are relatively short-lived and are readily replaced by new cells. The source of the new cells is the rapidly dividing area at the foot of the villi called the "Crypts of Lieberkuhn." It is right at the crypt where the parvovirus strikes.
Without new cells coming from the crypt, the villus becomes blunted and unable to absorb nutrients. Diarrhea in large quantities results not to mention nausea. The barrier separating the digestive bacteria from the blood stream breaks down. The diarrhea becomes bloody and bacteria can enter the body causing widespread infection (remember that that virus has simultaneously destroyed the bone marrow's ability to respond immunologically).
The virus kills one of two ways:
HOW IS SURVIVAL POSSIBLE?
Even parvovirus cannot disrupt the entire immune system. Plus, every day that goes by allows more antibody to be produced. This antibody can bind and inactivate the virus. Whether survival is possible amounts to a race between the damaged immune system trying to recover and respond versus the fluid loss and bacterial invasion.
Disease associated with the canine parvovirus started appearing around 1978. It is postulated that this virus is a mutation of the feline distemper virus. Since so few dogs had developed natural antibodies in the late 1970's, a large number of dogs died from this disease. In some cases, the virus affected the heart, and caused death within a few hours. We can still remember people coming into our clinic in droves to get their dogs vaccinated. There was no parvo vaccine for dogs then, since we did not even know what parvo was. The vaccine we gave initially was the cat feline distemper vaccine since there was no dog parvo vaccine available at the time. Our universities and drug companies immediately responded to the challenge, and identified the virus and manufactured a highly effective vaccine.
20 years later most dogs have encountered the parvovirus, either naturally (maternally) or through vaccines. These natural antibodies pass on to puppies (called maternal antibodies) when they nurse in the first few days of life. Maternal antibodies initially give a pup protection from parvovirus, along with many other viruses and bacteria. They last for a variable period of time, and start diminishing by around 2 months of age, yet can stay around until 5 months. It is at this time that a pup starts becoming vulnerable to the parvovirus, so we begin vaccines then. We never know exactly when these maternal antibodies diminish, which is why we give the parvo vaccine in a series. If we start the series much before 2 months of age we are wasting it because the maternal antibodies will negate the effects of the vaccine. In essence, we are trying to give the vaccine just as the maternal antibodies are diminished and just before the pup becomes susceptible to an exposure to the parvovirus.
There are reports of people and cats getting this disease, but in our locale this is almost non-existent. Pigs can get their own version of parvovirus, but it does not affect dogs or act in a similar manner.
This disease is still prevalent, as evidenced by the number of e-mails we receive regarding this topic. Many of these dogs would not suffer this problem if they were properly vaccinated. Preventing this disease is dramatically more effective (not to mention less expensive) than treating it.
The disease is caused by a highly contagious virus that is transmitted mostly by dogs orally contacting infected feces. Being a virus, they contain only DNA or RNA, and are not capable of reproducing unless they invade a cell. Once inside the cell they take over and force the cell to produce so many new virus particles that the cell eventually bursts, releasing these new virus particles into the bloodstream and tissues so they can invade other cells. The only thing that can stop this is the immune system.
Viruses are the smallest of know living organisms, and can only be seen with special microscopes called scanning electron microscopes, that cost millions of dollars (ours is on order). The parvovirus is extremely small (the Latin word for small is parvo)- just 1 thimble full of stool can contain millions of virus particles. It is easy to see why contamination occurs so readily. Incubation period varies from 5-10 days.As in many viral diseases of the intestinal tract, some dogs can pick up the disease and shed the virus without significant symptoms in themselves.
This is an electron microscope view of a cluster of parvo virus particles. It is courtesy of Dr. Cornelia Büchen-Osmond Biosphere 2 Center. "Universal Virus database of the International Committee on Taxonomy of Viruses, ICTVdB.
The scale at the bottom shows the length of 100 nanometers (nm). A nanometer is 1 billionth of a meter, so it is obvious these particles are real small
The virus has 3 basic strains:
1. CVP2 which was the first one found in 1978
2. CVP2a came on the scene in the early 80's
3. The strain most prevalent today is CVP2b
Eventually a new strain will appear because the virus will adapt to the immune system of dogs.
The parvovirus can linger in the environment for many months, allowing it to affect other dogs. It can withstand common household disinfectants (except bleach) and can withstand freezing winter temperatures. It can be spread on the hair and feet of dogs, in addition to shoes, clothes, and eating utensils.
We tend to see parvo in dogs that have other diseases, especially intestinal parasites (worms). This might be because these dogs have immune systems that are weakened, making them more susceptible to a viral infection. Also, the parvo virus capitalizes on the fact that the lining of the intestines of these dogs with intestinal parasites are damaged and susceptible to the parvovirus.
Parvovirus has a predilection for rapidly dividing cells (similar to cancer). The rapidly dividing cells in a dog are the intestines, bone marrow, and the immune system. When the virus infects these areas the lining of the intestine literally dies, the bone marrow cannot make red or white blood cells in adequate quantity, and the immune system can become impaired.
Initially the virus replicates in the tonsils (which are lymph nodes) after oral ingestion. The virus rapidly multiplies and enters the bloodstream within a few days. From here it spreads to those parts of the body that contain rapidly dividing cells as mentioned above.
The main cause of death in parvo infected dogs is septicemia. Poisons from bacteria that are attacking the susceptible lining of the intestines release toxins into the bloodstream. These toxins add to the complications of a puppy that is dehydrated from vomiting, diarrhea and not eating, is hypoglycemic from not eating, and has electrolyte imbalances from vomiting and not eating. The bodies immune system becomes overwhelmed and death ensues if treatment is not instituted early and aggressive enough. Even if toxins are not released by bacteria, the dehydration and electrolyte imbalance that occurs can lead to shock and eventual death.
In actuality, whether a pup recovers from the virus depends on a race between parvovirus particles causing septicemia and dehydration, and the immune system's ability to neutralize the virus. Fortunately, for most pups that get medical care, the good guys win the race.
The majority of dogs presented with parvovirus show signs of fever, lethargy, vomiting, diarrhea, and lack of appetite. In severe cases the diarrhea is very watery and frequently bloody, with a telltale odor. They are very ill, with significant abdominal pain. The virus is so strong that it literally causes the lining of the intestines to slough. It is painful to eat, and with the severe diarrhea and vomiting that is present, they rapidly become dehydrated. The also have a disruption in their electrolytes (sodium, potassium, chlorine) that adds to the weakness.
There is a complication that can occur from all the intestinal activity regarding vomiting and diarrhea. It is called an intussusception, which is literally a telescoping of the intestine into itself. This will cause the intestine to die, resulting in death of the pup. Treatment is surgical, unfortunately, these pups are in no shape for surgery. Luckily we do not encounter this very often, if at all.
In the peracute form of this disease the virus attacks the heart and causes rapid death. Fortunately, it is rare to encounter this nowadays.
The diagnosis of canine parvovirus is frequently made by age of pet (usually under 6 months of age), symptoms exhibited, and physical exam. Other diseases can mimic the signs of parvovirus, so x-rays and routine blood samples are sometimes run to help eliminate them as a cause. A CBC (complete blood count) might show a reduced white blood cell level, an indication that a virus is present in the body. A blood sample can be run looking for Parvo antibodies, but the results are open to interpretation as to whether the dog has an active infection or not.
An accurate, simple to perform, and inexpensive test has been developed to test the feces for the virus. It is called a CITE test, and can be performed by our in hospital lab within 15 minutes. Recent vaccinations can interfere with the interpretation of this test. No test is perfect though, and like many diagnostic tests for diseases, there can be false positives and false negatives. Lets look at how we perform and interpret this test:
A sample of feces is obtained from the rectum and placed in the first test well.
A special probe is placed sequentially in the 4 test wells over a 5 minute period of time.
The results are obtained by analyzing the blue dots on the bottom of the probe.
The test on the left is negative, the one on the right is positive.
Here are all the possible interpretations
Dogs with parvovirus need immediate veterinary care because they are usually very sick. They should not be treated at home if they are significantly ill. This care involves large amounts of intravenous fluids, added electrolytes, antibiotics, and special medications to minimize vomiting. It is common for them to be hospitalized for 5 days. We will monitor red blood cell counts and protein levels to identify those dogs that are not responding to routine treatment. If the protein level becomes low we institute therapy with additional fluids (called colloids) to combat the problem. Dogs that continue to decline in spite of therapy may also need a blood transfusion because they can become anemic and deplete their protein. We will also treat the internal parasites that can be an integral part of this disease.
We do not feed them until they have gone 24 hours without vomiting. We will send your dog home if it is eating and not vomiting for 24 hours. We expect it to have a persistent soft stool or diarrhea for several days after returning home.
Special precautions are taken when we treat parvo dogs. They are put in a special area so that we can monitor them closely. They are also isolated so that other dogs in the hospital are not exposed to the virus. Staff members that treat them wear disposable gloves and gowns, and clean their shoes in a special chlorine foot bath to prevent hospital contamination of the virus.
Fortunately, most dogs recover with our intensive therapy, although there still is an occasional dog that does not. This may be due to a weak immune system that can not produce adequate antibodies, or a particularly strong (virulent) strain of the virus that we encounter occasionally. Dobermans and Rottweilers seem to be especially sensitive to this virus, and have the most difficult time recovering from an infection.
Once your dog is well on its way to recovery we will send it home with antibiotics to be given orally along with a bland food. Even though the pup might be ravenous, feed the food in small amounts frequently. It should be rechecked within a week to make sure it is putting on weight and thriving. Only then will we continue (or in some cases begin) its routine vaccination series. Since the pup is potentially contagious to other dogs, it is well advised to keep it away from other animals for at least 30 days since it can still spread the virus.
Pups that have recovered from parvo do not get the disease later in life. They can completely recover and lead a normal life.
As with all infectious diseases, minimizing exposure from infected animals is the most effective means of prevention. Since infected dogs shed large amounts of virus in their stool, contamination is always a possibility. The virus is quite resistant in the environment, especially in public areas that are not disinfected. This is a good reason to keep your pup away from these areas until it is older, worm free, and had its full series of dog vaccines.
Since this disease occurs mostly in puppies, worms (internal parasites) and poor nutrition add susceptibility. Puppies should be wormed frequently until they are 3 months old.
Any dog you already have in the household before you exposed it to a parvo dog you recently brought in (whether it died or recovered from the parvo) should be current on its vaccines and should have minimal exposure, if possible, to the contaminated areas. It is rare for an adult dog that is current on its parvo vaccine (yearly boosters) to get parvo.
If you had a dog die of parvo we recommend thorough cleaning with diluted bleach (1:30 with water, or 4 ounces of Clorox in a gallon of water) and waiting 1-2 months before introducing a new dog to the area. Spray the yard as best as possible with a hose and keep new dogs away from the area for 1-2 months. Never put bleach on your dog.
Vaccines are highly effective. Ideally, we should vaccinate pups every 2 weeks starting at 6 weeks of age and lasting until 5 months of age. This is not realistic for most people though. Fortunately, parvo vaccines given at 8, 12, and 16 weeks of age are highly effective. Puppies should not be exposed to other dogs or the feces of other dogs until the vaccine series is complete.
If you are a dog owner, you will probably agree that your pet holds a special place in your heart. But you must remember that keeping your dog's heart healthy is one of your responsibilities.
"When it comes to heart disease, regular visits to your veterinarian could mean the difference between life and premature death," says Dr. Joanne Bicknese. "Dog owners may not realize that their pets are susceptible to many forms of heart disease. In most cases, heart disease can be successfully managed with early detection and treatment".
What is Heart Disease in Dogs?
Heart disease in dogs, as in people, can be either present at birth or acquired, often developing during middle age. Acquired heart disease is more common, affecting many older dogs.
Are there different types of heart disease in dogs?
Yes, there are two common types of heart disease in dogs:
Both types develop gradually over time and result in the same serious condition called heart failure.
A major threat to your dog's health is heart failure. Of the dogs in the United States examined annually by a veterinarian, approximately 3.2 million have some form of acquired heart disease and may be in heart failure. Heart failure results from the heart's inability to pump blood at a rate required to meet the body's needs. While continuing to work harder to pump blood, further heart damage can occur.
What are the signs of heart disease in dogs?
Although some of the early stages of heart failure in dogs have no visible signs, heart failure can be diagnosed through a clinical evaluation by a veterinarian. Dogs with mild to moderate heart failure typically experience heart enlargement, coughing, lethargy and difficulty breathing. Severe heart failure is characterized by difficulty breathing (even at rest), fainting, profound intolerance to exercise, loss of appetite and weight loss.
How can I find out if my dog has heart disease?
Your veterinarian is your dog's healthcare expert. Regular veterinary visits are important for early detection of health problems.
Your veterinarian may ask you for specific information about your dog before performing a thorough physical examination. If indicated, blood and urine tests, X-rays, an EKG or other tests may be ordered. Regular testing is important for early detection of heart disease in dogs.
"Too often, dog owners do not take their dogs to visit the veterinarian until they are displaying severe signs of heart failure, and by then it may be too late," says Dr. Bicknese. "When heart disease is detected in your dog, your veterinarian can recommend a schedule of regular visits and discuss a treatment plan that can help."
Can dogs with heart disease be treated?
Yes. Although there is no cure for most heart disease in dogs, new treatments are available. Success of treatment depends on various factors, but early detection is always best. By following your veterinarian's recommendations, you can help your dog live a longer, more comfortable life.
Keeping Your Dog Healthy
In addition to safeguarding your dog's heart, there's a lot you can do to keep your dog happy and in top shape. Ensure that your dog gets a moderate amount of exercise on a regular basis and has a balanced diet. An obese dog may have a harder time staying healthy.
Avoid the heartbreak of seeing your family's best friend fall ill. Proper care and veterinary supervision can help you watch your dog grow to a "hearty" old age.
The life cycle of the heartworm begins when an infected dog, carrying tiny immature heartworms (microfilariae) circulating in its blood, is bitten by a mosquito. The mosquito takes in microfilariae (larvae) when it feeds.
During the next two-three weeks, the larvae develop within the mosquito into the infective stage.
When the mosquito feeds again, it can
transmit infective larvae to the healthy dog. The larvae penetrate the dog's skin and migrate through the tissues and develop over the next few months, eventually reaching the dog's heart.
Once in the dog's heart, the worms can grow to as long as 14 inches and cause significant damage to the heart, lungs and other vital organs. If left untreated, heartworm disease can result in death.
Can my dog get heartworm disease?
Yes. Your dog can get heartworm disease, whether he's an "outside" dog or even if he stays inside most of the time. Dogs get heartworm disease from mosquitoes. It is the female mosquito that bites and transmits the infection. Female mosquitoes are very tiny and can easily slip through cracks around windows, doors or screens. Every dog can be at risk, indoors or out.
Are some dogs more susceptible than others?
Unfortunately, no dog, or breed of dog, is immune to heartworm disease. The mosquito that bites your dog could be carrying this common and deadly parasite. One bite from an infected mosquito is all it takes for your dog to become infected.
How can I know for sure if my dog already has heartworm?
The only way to know for sure is to have your family veterinarian examine and test your dog. The procedure is quick and easy. But don't delay in calling your veterinarian to arrange for a heartworm test. If your dog gets heartworm disease, treatment can be dangerous for him and expensive for you.
When is the right time to get my dog tested?
Mosquitoes, the carriers of heartworm disease, can be found at varying times of the year depending on the climate. Ask your veterinarian when the best time is to have your dog tested.
How can I prevent my dog from getting heartworm disease in the future?
If your veterinarian determines that your dog is free of heartworms, he or she will tell you how easy and convenient prevention can be. It's important to follow your veterinarian's instructions; if you don't, your dog could still be at risk. Remember, the first, most important step is to have your dog tested for heartworms.
Dog owners, be aware of the following:
Alex, a Labrador retriever, lives in a heartworm-endemic state. He has heartworms, but his owners don't know it because the disease is not easily detected until its later stages. Alex travels with his owners on vacation to states where there are fewer incidences of heartworm disease like Alaska. While in Alaska, Alex is bitten by a mosquito, which picks up the heartworm larvae from his bloodstream. Later, the same mosquito bites a healthy local dog, infecting him with heartworm. The cycle continues.
A problem can also result if a dog from a low-incidence state like Alaska travels into a state where heartworm disease thrives, is bitten by a mosquito and then brings the disease back home.
What Does This Mean For All Dog Owners?
Now that greater numbers of people are traveling across the country with their dogs, on vacation or visiting friends and relatives, no state is entirely heartworm-free. Heartworm disease continues to pose a threat to dogs across the United States. Because heartworm disease is potentially fatal, owners should visit their family veterinarian to learn how easy and convenient prevention can be.
When Traveling, Help Protect Your Dog from Heartworm Disease
Younger dogs and puppies are the most susceptible to infection. Among puppies, the death rate from distemper often reaches 80%. The disease also strikes older dogs, although much less frequently.
Even if a dog does not die from the disease, its health may be permanently impaired. A bout with canine distemper can leave a dog's nervous system irreparably damaged, along with its sense of smell, hearing or sight. Partial or total paralysis is not uncommon, and other diseases — particularly pneumonia — frequently strike dogs already weakened by a distemper infection.
Cats are not susceptible to canine distemper. The so-called "cat distemper" is a different disease caused by a different virus. Neither disease is transmissible to humans.
What Does Distemper Do?
Canine distemper is a highly contagious disease caused by a virus.
Canine distemper virus is most often transmitted through contact with respiratory secretions. Contact with the urine and fecal material of infected dogs can also result in infection.
The many signs of distemper are not always typical. For this reason, treatment may be delayed or neglected. The disease frequently brings about something like a severe cold. Most infected dogs have a fever and "stuffed up" head. Exposed animals may develop bronchitis, pneumonia and severe inflammation of the stomach and intestines.
The first signs of distemper an owner might notice are squinting, congestion of the eyes, and a discharge of pus from the eyes. Weight loss, coughing, vomiting, nasal discharge, and diarrhea are common. In later stages the virus frequently attacks the nervous system, bringing about partial or complete paralysis as well as "fits" or twitching. Dogs suffering from the disease are usually listless and have poor appetites.
Sometimes the signs may be very mild and perhaps go unrecognized, or the dog may have a slight fever for a couple of weeks. If pneumonia, intestinal inflammation or other problems develop, recovery takes much longer. Nervous problems often last many weeks after the animal has recovered from all other signs of infection. Occasionally the virus causes rapid growth of the tough keratin cells on the footpad, resulting in a hardened pad.
Distemper is so prevalent and the signs so varied that any sick young dog should be taken to a veterinarian for a definite diagnosis.
Prevention and Protection
Dogs that survive a natural infection usually develop sufficient immunity to protect them from distemper the rest of their lives. Many dogs — particularly pups — do not survive a naturally-acquired infection. The safest protection is vaccination.
Puppies born to dogs which are immune to distemper acquire a degree of natural immunity from nursing. This immunity is acquired through substances in the colostrum, which is the milk produced by the mother the first few days after giving birth. The degree of protection a pup receives varies in proportion to the amount of antibody its mother has, but the protection diminishes rapidly.
Your veterinarian can determine the most advantageous time to begin vaccination based upon his or her experience and the general health of your dog. Ask your veterinarian about a recommended vaccination schedule.
CPV infection is spread by dog-to-dog contact and has been diagnosed wherever dogs congregate, including dog shows, obedience trials, breeding and boarding kennels, pet shops, humane shelters, parks and playgrounds.
A dog that is confined to a house or yard and is rarely in contact with other dogs is far less likely to be exposed to the virus. CPV infection can only be transmitted to dogs and other canids, not to other types of animals or people, but animals and people can carry it to your dog.
The source of infection is fecal waste from infected dogs. Large amounts of the virus may be present in fecal material of infected dogs. The virus is resistant to extremes in environmental conditions and can survive for long periods. It is readily transmitted from place to place on the hair or feet of infected dogs or by contaminated cages, shoes, or other objects. Definitive information on other means of transmission, if any, is lacking.
How Can You Tell If A Dog Has CPV Infection?
The first signs of CPV infection are depression, loss of appetite, vomiting, and severe diarrhea. Rectal temperatures may be raised. These signs will most often appear 5-7 days after the dog is exposed to the virus. At the onset of illness, the feces will generally be light gray or yellow-gray. Sometimes, the first sign will be fluid feces streaked with blood.
Dogs may dehydrate rapidly due to vomiting and diarrhea. Some dogs may vomit repeatedly and have projectile and bloody diarrhea until they die. Others may have loose feces and recover without complications.
Most deaths occur within 48-72 hours following the onset of clinical signs. Pups suffer most with shock-like deaths, occurring as early as two days after the onset of illness. In the past, a high percentage of pups less than five months old and 2-3% of older dogs died from this disease. Now, due to widespread vaccination, these percentages have decreased dramatically.
Puppies, between weaning and six months of age are at increased risk of acquiring the disease. There appears to be a higher risk of severe disease in certain breeds (e.g. Rottweiller and Doberman Pinscher).
How Is CPV Infection Diagnosed and Treated?
A veterinarian will make the initial diagnosis based on clinical signs but only after considering other causes of vomiting and diarrhea. Evidence of rapid spread in a group of dogs is strongly suggestive of CPV infection and may be confirmed by testing feces for the virus. Some tests may be available in your veterinarian's office. Your veterinarian may choose to send samples to an outside laboratory, however. There are no specific drugs that kill the virus in infected dogs.
Treatment of CPV infection, which should be started immediately, consists primarily of efforts to combat dehydration by replacing electrolyte and fluid losses, controlling vomiting and diarrhea, and preventing secondary infections with antibiotics.
Sick dogs should be kept warm and be provided good nursing care.
Prevention and Protection
With a few exceptions, dogs of any age should be vaccinated to prevent CPV infection. Unless the actual immune status of a pup or litter is known, it is recommended that a series of vaccinations be given to provide adequate protection. Ask your veterinarian about a recommended vaccination schedule.
Proper cleaning and disinfection of kennels and other areas where dogs are housed is essential to control spread of the virus. Remember, the virus is capable of existing in the environment for many months unless the area is thoroughly cleaned. Sodium hypochlorite solution, such as one-quarter cup household bleach in 1 gallon of water, is an effective disinfectant.
An owner should not allow a dog to come in contact with fecal waste of other dogs when walking in a park or playground or along city streets. This is especially true until six months of age. Prompt and proper disposal of waste material is always advisable. Check lawns, sidewalks, and street gutters for fecal waste from neighborhood dogs, and urge friends to do the same.
If you are unsure whether this disease is affecting dogs in your community, check with a veterinarian. The risk of exposure can be reduced if you prevent your dog from contacting other dogs in areas where the incidence of CPV infection is alarmingly high.
Bordetellosis is caused by bacterium Bordetella bronchiseptica which is present in the respiratory tracts of many animals. It is a primary cause of tracheobronchitis (kennel cough) which results in a severe chronic cough. In addition to the cough, some dogs develop a nasal discharge. Transmission most frequently occurs by contact with the nasal secretions of infected dogs.
Vaccination is usually accomplished by the use of a nasal spray. There are several effective schedules and methods for administering the vaccine. Your veterinarian will establish a schedule that is best for your dog.
Parainfluenza is caused by a virus which produces a mild respiratory tract infection. It is often associated with other respiratory tract viruses. In combination these viruses are usually transmitted by contact with the nasal secretions of infected dogs. The vaccine to protect against this disease may be combined with other vaccines to offer broader protection.
Leptospirosis is a bacterial disease that impairs renal (kidney) function and may result in kidney failure. Clinical signs include vomiting, impaired vision, and convulsions. The disease is transmitted by contact with the urine of infected animals or by contact with objects that have been contaminated with the urine of infected animals.
Current Issues on Infection and Vaccination
Leptospirosis, a contagious disease affecting both animals and humans and spread by infection with a bacterial pathogen called Leptospira, may result in chronic liver and kidney disease and fatality in the dog. Over the past 30 years, preventative vaccination against two of the most common Leptospires, L. canicola and L. icterohaemorrhagiae, have nearly eradicated clinical disease associated with these strains among the inoculated population. Though not without potential side effects associated with allergic reactions to inoculant in a small number of dogs, the risks of not vaccinating for Leptospirosis once far outweighed risks of vaccine-reaction. In recent years, however, new outbreaks of Leptospirosis have been reported in the population of vaccinated dogs. Clinical evidence now suggests that these new cases are associated with the once, less-common Leptospires for which current vaccines do not protect against. In light of these findings, the process of vaccinating dogs with the current Leptospirosis vaccines is being seriously questioned.
The following article provides a detailed examination of infectious Leptospirosis in the canine and the recent clinical findings and misconceptions surrounding the controversy of using current vaccines to immunize dogs.
The Leptospira Organism. Leptospires are known as "aquatic spirochetes": they thrive in water and appear long and helical with a characteristic hook on one or both ends. These organisms are divided into two species, Leptospira biflexa and Leptospira interogans, the latter of which is pathogenic in animals and humans. L. interogans is divided into strains, or serovars, based upon the types of antigens (cell-surface markers against which the infected host will make antibodies) on their surface. These cell surface antigens provide little cross-immunity against one serovar and the next; that is, a dog that has developed immunity to one strain by either previous infection or vaccination will not be able to immunologically fend-off an infection of a different, subsequent strain. Despite this, however, these antigens may be cross-reactive in serological testing; that is, diagnostic testing to differentiate one serovar infection from another may lead to false-positive results because some antigens from one strain may have similarities to antigens from another strain.
Serovar prevalence. As recent as the 1980s, L. icterohaemorrhagiae and L. canicola were identified as the most prevalent serovars causing Leptospirosis in the canine. By the 1990s, however, an increased incidence of L. grippotyphosa and L. pomona was observed in conjunction with a resurgence of Leptospirosis disease suggesting a changing trend in the epidemiology of this disease. It is speculated that these changes in serovar prevalence are related to two primary factors that may strongly influence the epizootiology of Leptospira serovars. These factors are: 1) preventative vaccination has all but eradicated clinical disease in the domestic dog and 2) there has been an increased migration of wildlife, for which serovar infections with L. grippotyphosa and L. pomona are most prevalent, into suburban areas.
Modes of Disease Transmission. Leptospira thrive in spring and autumn when wet soil conditions and moderate temperatures support their otherwise poor environmental survivability. Infection by contact with infected urine or ingestion of urine-contaminated water is the most common means of transmission of the disease. Less common modes of infection include transmittance of the organisms during breeding, gestation, or through the membranes of the eyes, abrasions or bite wounds, or ingestion of the flesh from infected animals such as rats, raccoons, skunks or opossums. A serovar infects the dog as a maintenance host, using the dog to carry out most, if not all of the organism's life cycle. Under these conditions, the kidneys of the infected dog become the "breeding" grounds for the serovar, some of which will be shed in the urine where they may gain access to other dogs and continue the infectious cycle.
Symptoms of disease. During the first 4-12 days following infection with Leptospira, the dog may experience sudden symptoms of fever (103-105oF), depression, vomiting, loss of appetite, conjunctivitis, and generalized pain. Within 2 days of the onset of these primary symptoms, body temperature may drop suddenly and there may be a noticeable increase in thirst. A definite change in the color of the dog's urine and/or jaundice (icterus) is often noticed and may be the only indication of disease. Color intensity of the urine may vary from lemon to deep orange. Additionally, frequent urination and subsequent dehydration (uremia) are consistent with invasion of the kidney tubule cells by the Leptospira organism and usually present within a few days of the primary symptoms. In advanced cases of infection, profound depression, difficulty breathing, muscular tremors, bloody vomitus and feces are often observed as the infection progresses to include the liver, gastrointestinal system and other organs. Course and severity of the disease is often dependent upon the serovar responsible for the infection. Serovars associated with liver infection and symptoms of urine discoloration and/or jaundice (icterus), elevation of liver enzymes, and gastrointestinal symptoms include L. icterohaemorrhagiae and grippotyphosa. The serovar grippotyphosa is also associated with symptoms of renal failure as is the serovar pomona.
Diagnosis. Given the nonspecific symptoms often associated with Leptospira infection, definitive diagnosis must be based on the combination of symptoms and results from laboratory and serologic tests. Despite this, however, Leptospirosis should be among the primary suspected causes of illness in dogs presenting with sudden-onset kidney dysfunction. Laboratory testing of blood chemistry and urine provide evidence of abnormalities of components of the blood, elevation in liver enzymes, electrolyte imbalances, and active urinary sediments all consistent with vascular, liver, and kidney disease associated with Leptospira infection. The most commonly used serologic test includes the microscopic agglutination test (MAT), which titrates reactivity of antibodies in the patient's serum with live leptospires. Limitations to MAT include false-negative results early in the course of the disease, reduced positive response in vaccinated dogs that may be harboring chronic infection, and cross-reactivity excluding the ability to distinguish between serovars. Other serological tests including the enzyme-linked immunosorbent assay (ELISA) and microcapsular agglutination test (MCAT) are more specific, reducing false-positives associated with vaccinal responses and providing earlier detection by monitoring immunoglobulins specific for immune response to infection (IgM), respectively.
Treatment. Antibiotic therapy in the early course of Leptospirosis infection is efficient in shortening duration of the disease, reducing the time period for risks of contagion, and decreasing the severity of liver and kidney damage. In advanced cases, supportive therapy to compensate for abnormal blood, kidney and liver function may be required. Therapy to restore urine production, kidney filtration and blood flow are essential to reversing kidney failure. In cases of severe liver disease, a decrease in clotting factors in the blood may lead to bleeding disorders requiring treatment by transfusion. Since Leptospirosis poses a risk of contagion to other animals and to humans, special precautions must be taken to prevent transmission of Leptospira from the dog to other animals and human companions or caretakers. All blood, urine, and tissues from a dog suspected or determined to have Leptospirosis must be handled as biologically hazardous waste. Infected dogs should be quarantined and areas of contamination should be washed and disinfected with an iodine-based solution. It is important to note that even after treatment and control of the active disease state, dogs continue to shed serovar in their urine and therefore, may pose an infectious risk to other animals and to humans up to 3 months following infection.
Prognosis. Fatalities as a direct result of Leptospirosis do not usually exceed 10% and usually occur 5-10 days after initial onset of the disease. Death arising from secondary complications associated with progressive kidney and liver damage are common but may not occur for long periods following the initial disease.
Prevention. Commercial vaccines are available and protect against clinical disease associated with the L. icterohaemorrhagiae and L. canicola serovars. Inoculation does not, however, prevent infection and development of a carrier state whereby the dog will be clinically asymptomatic for disease yet provide a source of contagion through the shedding of serovars in its urine. Additionally, vaccinating against these specific serovars does not afford protection against other serovars.
What are coccidia?
In dogs and cats, most coccidia are of the genus called Isospora. Isospora canis and I. ohioensis are the species most often encountered in dogs. Regardless of which species is present, we generally refer to the disease as coccidiosis. As a puppy ages, he tends to develop a natural immunity to the effects of coccidia. As an adult, he may carry coccidia in his intestines, and shed the cyst in the feces, but experience no ill effects.
How are coccidia transmitted?
A puppy is not born with the coccidia organisms in his intestine. However, once born, the puppy is frequently exposed to his mother's feces, and if the mother is shedding the infective cysts in her feces, then the young animals will likely ingest them and coccidia will develop within their intestines. Since young puppies, usually those less than six months of age, have no immunity to coccidia, the organisms reproduce in great numbers and parasitize the young animal's intestines. Oftentimes, this has severe effects.
From exposure to the coccidia in feces to the onset of the illness is about 13 days. Most puppies who are ill from coccidia are, therefore, two weeks of age and older. Although most infections are the result of spread from the mother, this is not always the case. Any infected puppy or kitten is contagious to other puppies or kittens. In breeding facilities, shelters, animal hospitals, etc., it is wise to isolate those infected from those that are not.
What are the symptoms of coccidiosis?
The primary sign of an animal suffering with coccidiosis is diarrhea. The diarrhea may be mild to severe depending on the level of infection. Blood and mucous may be present, especially in advanced cases. Severely affected animals may also vomit, lose their appetite, become dehydrated, and in some instances, die from the disease.
Most infected puppies encountered by the authors are in the four to twelve week age group. The possibility of coccidiosis should always be considered when a loose stool or diarrhea is encountered in this age group. A microscopic fecal exam by a veterinarian will detect the cysts confirming a diagnosis.
What are the risks?
Although many cases are mild, it is not uncommon to see severe, bloody diarrhea result in dehydration and even death. This is most common in animals who are ill or infected with other parasites, bacteria, or viruses. Coccidiosis is very contagious, especially among young puppies. Entire kennels may become contaminated, with puppies of many age groups simultaneously affected.
What is the treatment of coccidiosis?
It should be mentioned that stress plays a role in the development of coccidiosis. It is not uncommon for a seemingly healthy puppy to arrive at his new home and develop diarrhea several days later leading to a diagnosis of coccidia. If the puppy has been at the new home for less than thirteen days, then he had coccidia before he arrived. Remember, the incubation period (from exposure to illness) is about thirteen days. If the puppy has been with his new owner several weeks, then the exposure to coccidia most likely occurred after the animal arrived at the new home.
Fortunately, coccidiosis is treatable. Drugs such as sulfadimethoxine (Albon®) and trimethoprim-sulfadiazine (Tribrissen®) have been effective in the treatment and prevention of coccidia. Because these drugs do not kill the organisms, but rather inhibit their reproduction capabilities, elimination of coccidia from the intestine is not rapid. By stopping the ability of the protozoa to reproduce, time is allowed for the puppy's own immunity to develop and remove the organisms.
How is coccidiosis prevented or controlled?
Because coccidia is spread by the feces of carrier animals, it is very important to practice strict sanitation. All fecal material should be removed. Housing needs to be such that food and water cannot become contaminated with feces. Clean water should be provided at all times. Most disinfectants do not work well against coccidia; incineration of the feces, and steam cleaning, immersion in boiling water, or a 10% ammonia solution are the best methods to kill coccidia. Coccidia can withstand freezing.
Cockroaches and flies can mechanically carry coccidia from one place to another. Mice and other animals can ingest the coccidia and when killed and eaten by a dog, for instance, can infect the dog. Therefore, insect and rodent control is very important in preventing coccidiosis.
The coccidia species of dogs and cats do not infect humans.
Coccidiosis is a parasitic disease of the intestinal tract caused by microscopic organisms called coccidia. The disease spreads from one animal to another by contact with infected feces. It is most severe in young or weak animals and often causes bloody diarrhea.
What are coccidia?
Coccidia are small protozoans (one-celled organisms) that multiply in the intestinal tracts of dogs and cats, most commonly in kittens and puppies less than six months of age, in adult animals whose immune system is suppressed or in animals who are stressed in other ways (e.g., change in ownership, other disease present).
In cats and dogs, most coccidia are of the genus called Isospora. Isospora canis and I. ohioensis are the species most often encountered in dogs; I. felis and I. rivolta are the most common in cats. Regardless of which species is present we generally refer to the disease as coccidiosis. As a puppy or kitten ages it tends to develop a natural immunity to the effects of coccidia. As an adult it may carry coccidia in its intestines, shed the cyst in the feces, but experience no ill effects.
How are coccidia transmitted?
A puppy or kitten is not born with the coccidia organisms in its intestine. However, once born, the puppy or kitten is frequently exposed to its mother's feces and if the mother is shedding the infective cysts in her feces then the young animals will likely ingest them and coccidia will develop within their intestines. Since young puppies and kittens, usually those less than six months of age, have no immunity to coccidia, the organisms reproduce in great numbers and parasitize the young animal's intestines. Oftentimes this has severe effects.
From exposure to the coccidia in feces to the onset of the illness is about 13 days. Most puppies and kittens who are ill from coccidia are, therefore, two weeks of age and older. Although most infections are the result of spread from the mother, this is not always the case. Any infected kitten or puppy is contagious to other puppies and kittens. In breeding facilities, shelters, animal hospitals, etc., it is wise to isolate those infected from those that are not.
What are the symptoms of coccidiosis?
The primary sign of an animal suffering with coccidiosis is diarrhea. The diarrhea may be mild to severe depending on the level of infection. Blood and mucous may be present, especially in advanced cases. Severely affected animals may also vomit, lose their appetite, become dehydrated, and in some instances, die from the disease.
Most infected kittens and puppies encountered by the authors are in the four to twelve week age group. The possibility of coccidiosis should always be considered when a loose stool or diarrhea is encountered in this age group. A microscopic fecal exam by a veterinarian will detect the cysts confirming a diagnosis.
What are the risks?
Although many cases are mild it is not uncommon to see severe, bloody diarrhea result in dehydration and even death. This is most common in animals who are ill or infected with other parasites, bacteria or viruses. Coccidiosis is very contagious, especially among young kittens and puppies. Entire kennels and catteries may become contaminated with puppies and kittens of many age groups simultaneously affected.
What is the treatment of coccidiosis?
It should be mentioned that stress plays a role in the development of coccidiosis. It is not uncommon for a seemingly healthy puppy or kitten to arrive at its new home and develop diarrhea several days later leading to a diagnosis of coccidia. If the puppy or kitten has been at the new home for less than thirteen days then it had coccidia before it arrived. Remember the incubation period (from exposure to illness) is about thirteen days. If the puppy or kitten has been with its new owner several weeks, then the exposure to coccidia most likely occurred after the animal arrived at the new home. The authors merely point this out as they have been involved in legal cases as to who was responsible for the cost of treatment, the breeder or new owner. Usually coccidia was present only to surface during the stressful period of the puppy or kitten adjusting to a new home.
Fortunately coccidiosis is treatable. Drugs such as sulfadimethoxine (Albon), trimethoprim-sulfadiazine (Tribrissen) and amprolium (Corid) have all been effective in the treatment and prevention of coccidia. Because these drugs do not kill the organisms, but rather inhibit their reproduction capabilities, elimination of coccidia from the intestine is not rapid. By stopping the ability of the protozoa to reproduce, time is allowed for the puppy's own immunity to develop and remove the organisms. Drug treatments of five or more days are usually required.
How is coccidiosis prevented or controlled?
Because coccidia is spread by the feces of carrier animals, it is very important to practice strict sanitation. All fecal material should be removed. Housing needs to be such that food and water cannot become contaminated with feces. Clean water should be provided at all times. Most disinfectants do not work well against coccidia; incineration of the feces, and steam cleaning, immersion in boiling water or a 10% ammonia solution are the best methods to kill coccidia. Coccidia can withstand freezing.
Cockroaches and flies can mechanically carry coccidia from one place to another. Mice and other animals can ingest the coccidia and when killed and eaten by a cat, for instance, can infect the cat. Therefore, insect and rodent control are very important in preventing coccidiosis.
The coccidia species of dogs and cats do not infect humans.