Canine distemper is common when raccoon populations are large. The virus is widespread and mortality in juveniles is higher than in adults. Feline distemper, also called feline panleukopenia, catplague, cat fever, feline agranulocytosis, and feline infectious enteritis, is an acute, highly infectious viral disease affecting members of the Felidae, Mustelidae and Procyonidae.
Signs and Symptoms
Canine distemper in raccoons starts slowly, initially appearing as an upper respiratory infection, with a runny nose and watery eyes developing into conjunctivitis (the most visible symptoms). As time wears on, the raccoon can develop pneumonia. The raccoon may be thin and debilitated and diarrhea is a clear symptom.
In the final stage of the disease, the raccoon may begin to wander aimlessly in a circle, disoriented and unaware of its surroundings, suffer paralysis or exhibit other bizarre behaviour as a result of brain damage. Many of these symptoms are indistinguishable from, and therefore often mistaken for, the signs of rabies which can only be determined by laboratory testing.
Raccoon distemper is cyclical and can spread and wipe out entire colonies of raccoons. The disease is transmitted through airborne droplets, direct contact with body fluids, saliva or raccoon droppings. Feline distemper usually begins suddenly with a high fever, followed by depression, vomiting, anorexia, diarrhea, and a profound leukopenia.
The course of the disease is short, rarely lasting over one week, but mortality may reach 100% in susceptible animals. Feline distemper virus is shed in all body secretions and excretions of affected animals. Fleas and other insects, especially flies, may play a role in transmission of the disease.
No treatment exists for canine or feline distemper (thereby increasing the need for prevention and control). Infected raccoons are usually euthanized. Control of distemper outbreaks includes the removal of dead animals' carcasses, vaccination of at-risk domestic species to decrease the number of susceptible hosts, and a reduction in wildlife populations which
also reduces the number of potential hosts. The canine distemper virus is inactivated by heat, formalin,and Roccal R. Disinfection of premises with a dilution of 1.30 bleach will help to reduce spread.
Unvaccinated dogs and cats that are allowed to wander unattended are at risk of infection from, as well as posing a risk of infection to, raccoons and other wildlife. Humans are not at risk from distemper as the disease cannot be passed on to people and presents no danger to humans. Dog and cat owners should make sure their pets have been vaccinated for the disease.
Owners of pet ferrets should have their animals vaccinated against canine distemper which is fatal in ferrets. Wildlife rehabbers should quarantine any new rehabs until they get a clean bill of health and should have the animals vaccinated against both canine and feline distemper.
Raccoons are the normal host for the parasitic nematode or roundworm known as Baylisascaris procyonis. It is the common large roundworm found in the small intestines of raccoons. Cotton rats are believed to be a possible intermediate host.
Adult raccoons are susceptible only to larvae from rodent tissue while young raccoons are susceptible to infection by egg ingestion where larva hatches in small intestine with migration apparently limited to wall of small intestine. This roundworm is zoonotic, meaning it can pass from animal to animal (or human). In the raccoon, these worms normally produce no symptoms in the infected host raccoon, other than possibly intestinal obstruction, and apparently do little or no harm to adult raccoons.
In the Midwest, prevalence is 70% for adult and 99% for baby raccoons according to the University of Missouri College of Veterinary Medicine. Adult worms measure 15 to 20 cm in length and 1 cm in width, tan-white in color, cylindrical and tapered at both ends. The eggs are ovoid, brown, with finely pitted outer shell, measure 70 x 55 microns and are passed in one-cell stage. The eggs embryonate into larva outside of host.
The disease is spread through the eggs contained in the feces of an infected raccoon, by ingesting either raccoon feces or things that have been in contact with raccoon feces. Adult female roundworms produce thousands to millions of eggs per day. After the eggs are shed in feces, they embryonate into a larval stage in about 3-4 weeks. They remain viable in the environment for months to over 5-6 years. When ingested, the larva migrate and reach lengths of 1.5 to 2.0 mm.
Signs and Symptoms
Clinical and pathological symptoms occur when an abnormal host (an animal other than the raccoon) becomes infected. It can cause a very rare disease called visceral larva migrans (VLM) in humans and other animals, as well as ocular larva migrans (OLM) and neural larva migrans (NLM). If ingested by an abnormal host, the eggs penetrate the small intestine (which they apparently do not do in raccoons) and undergo an aberrant migration through the body. The eggs hatch, and the larvae migrate to the brain, eyes and other organs. The parasite has been implicated in cases of serious eye disease or central nervous system disorders and infection can cause death or paralysis depending on the location in the body and number of worms.
Human toxocarosis via pets vs. Baylisascaris
It should be noted that visceral larva migrans and ocular larva migrans in humans (and other animals) can also be caused by feces of other animals - most notably pet dogs and cats. Human infection with the toxiocaris larvae of canine or feline roundworms is known collectively as toxocariasis. All cases of toxocariasis come from pets, according to the Texas Dept. of Health, Div. of Zoonosis Control, which states an estimated 10,000 new cases of roundworm infection occur in children every year, most often as a result of eating dirt contaminated with animal feces.
Most human infections are mild enough to go unnoticed and apparently produce no permanent damage. However sometimes infection results in severe and even fatal disease. Common symptoms include abdominal pain, headache, weakness, lethargy and wheezing. Due to the public health significance, it is important to distinguish Baylisascaris from Toxocara.
Not to minimize the risk, but in many states raccoons are being systematically euthanized because of the panic over perceived danger of transmission of the raccoon
roundworm to humans as a result of two documented cases (one a fatality) to date, including a case in 1998 where a child in Pacific Grove, California was infected by eating bark on firewood that had been contaminated by raccoon feces. Over 177 local wild raccoons were systematically executed before a lawsuit by the City's concerned citizens brought the killings to a halt. Eradication of raccoons will not prevent the very rare disease visceral larva migrans in humans. However, education and some common sense might.
Contact with wild raccoons or exposure to their feces should be avoided. Hunters, trappers, and wildlife rehabilitators should wash their hands after handling raccoons. Wild raccoons should be discouraged from inhabiting buildings or other areas used by humans. Prevention also consists of never touching or inhaling raccoon feces, using rubber gloves and a mask when cleaning cages (or attics, etc.) which have been occupied by raccoons, burying or burning all feces, keeping children and pets away from raccoon cages and enclosures, and disinfecting cages and enclosures between litters.
All cages and nest boxes used for housing raccoons should not be used for any other animals. They should remain strictly for raccoon use. Do frequent fecal screens on all raccoons in your possession. If positive, your wildlife vet may recommend de-worming your raccoon via treatment with an anthelmintic such as Panacur (brand of Fenbendazole) at .1 cc per pound of body weight each week until release or other accepted treatment. Remember that raccoons may have fecal matter on their paws and bodies and take appropriate safeguards.
While there is no known treatment for VLM or NLM, there are several drugs that can treat the parasite in raccoons. They include piperazine, pyrantel pamoate, or fenbendazole. Following is an abstract from a study testing the efficacy of six anthelmintics against luminal stages of Baylisascaris procyonis in naturally infected raccoons (Procyon lotor)
[JOURNAL. Bauer, C; Gey, A. Veterinary Parasitology, v.60, n.1-2, 1995:155-159] "Abstract: The efficacy of six anthelmintics against natural infections of Baylisascaris procyonis in raccoons (n = 7 per drug) was determined in a series of critical tests.
The drugs were given via moist cat food as a single dose or once daily for three consecutive days. Raccoons treated with pyrantel embonate (1 times 20 mg base kg-1 bodyweight (bwt.)), ivermectin (1 times 1 mg kg-1 bwt.), moxidectin (1 times 1 mg kg-1 bwt.), albendazole (3 times 50 mg kg-1 bwt.), fenbendazole (3 times 50 mg kg-1 bwt.) or flubendazole (3 times 22 mg kg-1 bwt.) expelled 1- 198, 2-24, 2-14, 3-80, 2-70, or 2-35 B. procyonis stages, respectively, within the faeces. No roundworm was detected in any raccoon at post mortem examinations 7 days after the end of treatment. These results suggest that any of the six anthelmintics can be used at the dose rates tested in a deworming programme for captive raccoons."
Conclusion and Opinion
When it comes to Baylisascaris procyonis, prevention and common sense should be used. Attempts to eradicate raccoon populations will not eradicate the problem and, particularly if the cotton rat is an intermediate host, may only compound it by removing a natural predator of the cotton rat. Further, it may upset the balance of nature, causing an unnatural increase in the skunk population, a reservoir of the non-raccoon strain of rabies, by removing a natural predator of baby skunks. All animals (human, domestic and wild) harbor parasites that can be transmitted to each other. Instead of panicking over a real but very rare danger, learn h
ow to minimze the risks of transmission. And don't eat any poop.
When it comes to rabies, ignorance can kill. Not just you or your pets, but innocent and healthy wildlife. Raccoons are the number one wild animal killed for rabies testing. Dogs and cats top the list of domestic animals killed for rabies testing. In both these and other animals, the vast majority are found NOT to have rabies.
They must pay with their lives because people have possibly been exposed to rabies by them. If these same people had taken precautions against possible exposure to rabies, these animals would still be alive. Don't be responsible for the death of an innocent animal. Learn about rabies and learn how to protect yourself, your family, your pets and our wildlife.
Raccoon rabies is a strain of rabies carried mainly by raccoons. Raccoon rabies is rabies. It can be spread to farm animals, pets and people through the saliva of an infected animal in the same ways as other strains of rabies. Raccoon rabies kills raccoons, other animals and humans in the same way as other strains of rabies do. The only difference is that it is spread primarily by raccoons.
Please read more about Rabies in our special section on the subject HERE!