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Rabies is a viral disease that affects the central nervous system of mammals, including humans. In Canada, bats, foxes, and skunks are the most common transmitters of the disease. Rabies is transmitted through saliva, primarily via bite wounds. It can also be spread when infected saliva comes into contact with a scratch, open wound or the mucous membranes of the mouth, nasal cavity or eyes. When the virus enters an animal's body, it moves through the nerves to the brain, where it multiplies quickly. The virus then spreads to the salivary glands and other parts of the body. Once clinical signs appear, rabies is almost always fatal.
WHAT WE ARE DOING
In conjunction with the government of Quebec and the Canadian Food Inspection Agency, the CWHC is involved in a surveillance program designed to detect and monitor the spread of the raccoon rabies virus variant in the province of Quebec. Several rabid raccoons and striped skunks have been detected as a result of this program. Results of this surveillance programme have helped to target areas for control measures such as rabies vector density reductions and vaccination programs involving wild raccoons. In addition, public prevention campaigns can be directed toward regions where this zoonosis is most prevalent.
Avian botulism is a paralytic disease caused by ingestion of a toxin produced by the bacteria, Clostridium botulinum. This bacteria is widespread in soil and requires warm temperatures, a protein source and an anaerobic (no oxygen) environment in order to become active and produce toxin. Decomposing vegetation and invertebrates combined with warm temperatures can provide ideal conditions for the botulism bacteria to activate and produce toxin. Outbreaks occur from coast to coast in the United States and Canada, generally from July through September. Thousands of birds may die during a single outbreak. Botulism in humans is usually the result of eating improperly home-canned foods, which contain types A or B toxin. Type E toxin has been associated with improperly smoked fish. People, dogs, and cats are generally thought to be resistant to type C toxin, but a few cases have been reported in people and dogs.
WHAT WE ARE DOING
Since this disease first appeared on the lower Great Lakes in 1998, the CWHC has been involved in cooperative efforts to monitor for the occurrence of suspected botulism events and to diagnostically confirm the presence of Type E botulism. Surveillance for this disease has, over time, required the combined efforts of personnel from the Canadian Wildlife Service, Parks Canada, Ontario Provincial Parks, the Ontario Ministry of Natural Resources and members of the public. The CWHC continues to encourage all of these groups to report unusual occurrences of avian mortality around the shores of the lower Great Lakes and facilitates the submission of carcasses to our laboratory. The ecological factors that drive the occurrence of Type E botulism remain poorly understood, which means that maintaining surveillance is important as we seek to learn more about these ecological drivers.
Bovine tuberculosis (TB) is a chronic disease of animals caused by a bacteria called Mycobacterium bovis, (M. bovis) which is closely related to the bacteria that cause human and avian tuberculosis. This disease can affect practically all mammals, causing a general state of illness, coughing and eventual death. The name Tuberculosis comes from the nodules, called 'tubercles', which form in the lymph nodes of affected animals. Until the 1920s when control measures began in developed countries, it was one of the major diseases of domestic animals throughout the world. Today TB remains an important disease of cattle, wild animals, and is a significant zoonosis (a disease of animals which can also infect humans).
Avian cholera is a disease caused by bacteria that can infect Common Eiders, Snow Geese, Canada Geese and Ross's Geese. Infected birds die quite suddenly, even while sitting on a nest. Sick birds may appear weak, unable to fly or unafraid of people. Birds dying of avian cholera are often in good body condition. Inside an affected bird, you may see bleeding on the surface of the heart and gizzard, and many small white spots on the liver. The disease was first recorded in the 18th century. However it was not until the 1880s that Louis Pasteur first isolated and grew it in pure culture. Originally a disease of fowl in Europe, it was first recorded in North America in 1943-44. Since then outbreaks have been recorded almost annually in wild birds including several outbreaks identified in Canada.
Tularemia is a bacterial disease that can affect animals and is found in wild animals in North America. Wild animals most often affected include rodents, rabbits, muskrats and beavers. Tularemia can be spread from animals to humans, although this is not known to occur commonly. There are two types of tularemia: Type A and Type B. Type A tularemia causes more serious illness in people, and Type B usually causes less severe illness in people. Tularemia is usually transmitted by contact with infected animals or their cages/immediate environment. This means: being bitten or licked by the animal, handling or cleaning the animal, its toys, cage and feeding equipment, breathing in air or dust contaminated with the bacteria, or eating or drinking contaminated food or water. Tularemia is not known to spread from person to person.
Salmonella are a group of bacteria that is found in the intestines of many animals. One example of the disease relevant to wildlife health is salmonellosis of songbirds. Salmonella enterica typhemurium is the strain that most commonly infects songbirds, resulting in seasonal epidemics in species that make use of bird feeders, such as house sparrows, chickadees, and redpolls. The bacteria can be spread from bird to bird through direct contact, or through ingestion of contaminated food or water. Symptoms vary among infected birds, and may include lethargy, ruffled feathers, and emaciation. Infected individuals shed the bacteria in their feces, contributing to the contamination of feeder sites. Bird feeders should be cleaned regularly to prevent the spread of salmonellosis in wild bird populations. If sick or dead birds are seen around the feeder, the feeder should be cleaned thoroughly and taken down for at least a week. Use caution and wear gloves when cleaning bird feeders or handling sick or dead birds, as Salmonella sp. can transmit to and cause illness in humans as well.