Parasites and Diseases
A Field Guide
TO COMMON WILDLIFE DISEASES
AND PARASITES IN ALASKA
What causes respiratory disease in wildlife?
- Respiratory disease is a disorder of the airways or lungs that affects breathing. One important infectious respiratory disease in wildlife is pneumonia.
- Pneumonia is complex and often multifactoral, meaning that it can involve more than one pathogen (including viruses, bacteria, and parasites).
- An animal may be exposed to a potential respiratory pathogen without developing pneumonia. Respiratory pathogens usually only cause severe damage to the lungs of animals already stressed (due to infection or other illness) or vulnerable (young or old age).
- In Dall's sheep, mountain goat, and muskox, pneumonia is most often caused by lungworms.
- Bacterial pneumonia can occur when damaged lungs (like those infected by lungworms) are also invaded by bacteria such as Mannheimia haemolytica and Bibersteinia trehalosi. These bacteria are common even in healthy animals and only cause disease in individuals that are otherwise injured or stressed.
Where does respiratory disease occur?
- Many wildlife including Dall's sheep, mountain goat, and muskox carry Mannheimia haemolytica and Bibersteinia trehalosi, but animals usually do not become sick unless exposed to other disease-causing organisms or illnesses. Large-scale die-offs are not likely to occur from these bacteria alone.
- In the lower 48 states, respiratory disease has caused large-scale die-offs in bighorn sheep. These outbreaks are thought to take place when enzootic (naturally occurring) bacteria exist concurrent with the bacteria Mycoplasma ovipneumoniae (often referred to as M. ovi).
- In some cases, M. ovi related respiratory disease outbreaks in wild bighorn populations have been linked to contact with domestic sheep and goats.
- Respiratory disease-related bighorn sheep die-offs have been documented in California, Idaho, Montana, Nebraska, Nevada, North and South Dakota, Utah, Washington, Wyoming.
What are the signs of respiratory disease?
- Common signs of respiratory disease in wildlife:
- Coughing (deep and hacking, with arched back and head down)
- Thick, opaque nasal discharge
- Difficulty breathing (with neck extended, mouth open)
- Sneezing repeatedly
- Infected lungs are firm with dark red to purple blotching instead of spongy and uniform pink. There are also often thick yellow attachments/adhesions to the rib cage.
How can I protect myself?
- Edibility of the meat should not be affected by respiratory disease. However, affected parts should be trimmed off and meat cooked thoroughly. Severely diseased animals may be in poor condition, reducing the quality and taste of the meat.
- It is not recommended to eat sick animals or meat that smells rotten (although the meat still must be salvaged).
Respiratory disease surveillance
- ADF&G's wildlife health surveillance program is monitoring reports of respiratory disease in Dall's sheep.
- Starting in 2017, nasal swabs were taken from select hunter-harvested sheep that were brought to ADF&G offices for sealing. These nasal swabs are being analyzed for the presence of M.ovi and other similar respiratory disease causing organisms.
- Studies have shown diseases are easily spread between domestic livestock and wild sheep. To reduce contact and the spread of disease, Alaska law prohibits the use of domestic goats and sheep as pack animals when hunting sheep, goat, or muskoxen.
Samples to collect!
- If you find a Dall's sheep with abnormal lung tissue (lungs should be spongy and uniform pink other than blood shot areas) immediately call or text the Wildlife Disease Surveillance reporting line 907-328-8354 or send an email to firstname.lastname@example.org. Record the location, take photos of the carcass and abnormal tissue and collect a lung for submittal to ADF&G.