Worms and Germs Blog : Animal Health & Diseases : University of Guelph : Ontario Veterinary College : Zoonotic Diseases : Guelph, Hamilton, Ontario

The latest edition of the journal Emerging Infectious Diseases contains an article about a South African vet student that acquired West Nile virus from a pony while performing a necropsy. Occupational exposure to infectious diseases is an inherent risk in veterinary medicine. Veterinarians know that they are at higher risk of encountering various infectious diseases and take (or should take) precautions to reduce those risks. Sometimes infections occur despite the best precautions. Sometimes infections occur because of bad practices. This report highlights the latter.

In this case, a 4-month-old pony began showing vague signs of illness, then developed neurological abnormalities and was euthanized. A necropsy (post-mortem exam) was then performed by a veterinary pathologist with the assistance of two veterinary students. As part of the necropsy, the student removed the brain and spinal cord for testing, but gloves were the only protective gear that were used. No face or eye protection was used, which is quite astounding.

The pony was eventually diagnosed with West Nile virus. Six days after performing the necropsy, the veterinary student developed a fever, malaise, sore muscles, stiff neck and severe headache. West Nile virus infection in the student was confirmed, and the viruses from the pony and person were the same type based on testing. Fortunately, the signs of infection in the student subsided after approximately ten days.

Horses are considered "dead-end" hosts for West Nile virus, meaning they cannot naturally transmit the virus. This is because horses (even severely affected ones) only have very low levels of virus in their blood, so a biting mosquito can't pick up the virus and transmit it to other individuals. However, the brain and spinal cord, particularly in a clinically affected horse, may contain very large amounts of the virus. It's astounding that a veterinary school would have a student removing the brain and spinal cord of an animal that died from a neurological condition, especially without proper protective gear, since the procedure carries a risk of splashing or aerosol exposure to the virus. Anyone performing necropsies needs to be aware of the potential risks and take appropriate precautions. The paper states that after the incident, biosafety practices were improved to include the wearing of masks and eye protection during necropsies. Well, I guess it's better late than never...

Click image for source.

This Worms & Germs entry was originally posted on our sister site, equIDblog, on 11-Mar-10.

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As the owner of a dog that loves to roll in (and eat) anything she finds, I certainly understand the questions that I get about risks to dogs from dead birds. Eating a dead bird is certainly not an appealing thought to us, but overall, the risks to a dog are pretty low. The greatest potential problem is likely gastroenteritis, often referred to as ‘garbage-gut’, which typically causes diarrhea (with or without vomiting) after "dietary indiscretion" (i.e. a dog eating things it shouldn't have). Another concern is Salmonella. Some birds carry Salmonella in their intestinal tracts and dogs could become infected from eating them. This is a bigger problem in cats that hunt birds - salmonellosis in outdoor cats is also referred to as songbird fever. West Nile virus can cause death in birds, especially species such as bluejays and crows, which may then be found by your dog. The risk of transmission of West Nile virus to dogs from eating dead birds is presumably very low. Further, this disease is very rare in dogs and they appear to be quite resistant to the virus.

• Try to prevent your pet from eating/touching dead birds.
• If your pet develops diarrhea after eating a dead bird, it is probably not a health concern for anyone else but Salmonella infection is possible, so consider taking your dog to the veterinarian. This is especially important if the dog appears sick (i.e. besides vomiting and diarrhea, the dog also is not acting like itself) or if there are people in the household that are at higher risk for getting sick from bugs like Salmonella (i.e. infants, people with weakened immune systems). All diarrhea should be considered potentially infectious to other animals and people.  Extra care should be taken around affected pets and their stool, including extra attention to hand washing, and disinfecting the site of any "accidents" that occur in the house.
• In some areas where bird testing is performed for West Nile virus or avian influenza surveillance, public health personnel will collect dead birds. Contact your public health department if you are unsure what is done in your region.

If you must move or remove a dead bird, precautions should be taken. These include:

• Do not touch dead birds with bare hands.
• Use heavy-duty, leak-proof gloves to place the bird in a leak-proof plastic bag. Alternatively, fold two bags over your hand and use the bag to cover your hand when picking up the bird (like people do when poop-scooping), or use a shovel to place the bird in a bag.
• Double bag the bird.
• If the bird is not being collected for testing, contact your local waste management agency regarding disposal instructions.
• Always wash your hands with soap and water as soon as you're done.

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