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Although reports of avian influenza (HPAI H5) have declined in recent weeks, the virus continues to cause wild bird deaths - and occasional spillovers into mammals (see Two States (Michigan & Minnesota) Report HPAI Infection In Wild Foxes) - across the country and around the world.
While its incidence in birds may be lower - summer can provide more opportunities for people and their pets to be exposed to the virus - as they visit parks and beaches.
Up until 20 years ago, dogs and cats were though to be relatively immune to human and/or novel influenza.
That perception began to change in 2004 when Equine H3N8 – an influenza that had been bouncing around in horses since the 1960s – jumped to Greyhounds at a racetrack in Miami, and soon canine influenza was off to the races as well (see EID Journal article Influenza A Virus (H3N8) in Dogs with Respiratory Disease, Florida).
At roughly the same time, half a world away, avian H5N1 was making big inroads across Southeast Asia, and zoos that kept large cats found to their dismay what happens when you feed infected chicken carcasses to tigers and leopards.
The following comes from a World Health Organization GAR report from 2006.
H5N1 avian influenza in domestic cats
28 February 2006
(EXCERPTS)
Several published studies have demonstrated H5N1 infection in large cats kept in captivity. In December 2003, two tigers and two leopards, fed on fresh chicken carcasses, died unexpectedly at a zoo in Thailand. Subsequent investigation identified H5N1 in tissue samples.
In February 2004, the virus was detected in a clouded leopard that died at a zoo near Bangkok. A white tiger died from infection with the virus at the same zoo in March 2004.
In October 2004, captive tigers fed on fresh chicken carcasses began dying in large numbers at a zoo in Thailand. Altogether 147 tigers out of 441 died of infection or were euthanized. Subsequent investigation determined that at least some tiger-to-tiger transmission of the virus occurred.
Since then we've seen numerous examples of human, avian, and other flu viruses infecting dogs, cats, mink, ferrets, and other peridomestic animals, along with evidence that they can serve as a `mixing vessel' for reassortant flu viruses.
Pathogens: Emergence and Characterization of a Novel Reassortant Canine Influenza Virus Isolated from CatsPerhaps the biggest wake up call came in late 2016 when we saw an avian H7N2 virus sweep through hundreds of cats housed at multiple New York Animal shelters - while also infecting at least two people - demonstrating that that cats can become efficient transmitters of a novel flu virus as well.
J. Clin. Microb: Serological Screening Of Dogs & Cats For Influenza A - Europe
China: Avian-Origin Canine H3N2 Prevalence In Farmed Dogs
Seroprevalence Of Influenza Viruses In Cats - China
Study: Dogs As Potential `Mixing Vessels’ For Influenza
J. Virology: Zoonotic Risk, Pathogenesis, and Transmission of Canine H3N2
Access Microbiology: Inter-Species Transmission of Avian Influenza Virus to Dogs
While the risk to human health is currently quite low, it isn't zero, and so the CDC is reminding people about the risks of dogs and cats coming into contact with infected birds and of the warning signs of possible avian flu.
First their updated advice, then I'll return with a brief postscript.
Bird Flu in Pets and Other Animals
Although bird flu viruses mainly infect and spread among wild migratory water birds and domestic poultry, some bird flu viruses can infect and spread to other animals as well. Bird flu viruses have in the past been known to sometimes infect mammals that eat (presumably infected) birds or poultry, including but not limited to wild animals such as foxes and skunks; stray or domestic animals such cats and dogs; and zoo animals such as tigers and leopards.
While it’s unlikely that people would become infected with bird flu viruses through contact with an infected wild, stray, feral, or domestic mammal, it is possible—especially if there is prolonged and unprotected exposure to an infected animal. This page provides information for different groups of people who might have direct contact with infected or potentially infected sick or dead animals, including animals that might have eaten bird flu-infected birds.
Pet Owners
If your domestic animals (cats or dogs) go outside and could potentially eat sick or dead birds infected with bird flu viruses, they could be infected with bird flu. While it’s unlikely that you would get sick with bird flu through direct contact with your infected pet, it is possible. For example, in 2016, the spread of bird flu from a cat to a person was reported in NYC. The person who was infected was a veterinarian who had mild flu symptoms after prolonged exposure to sick cats without using personal protective equipment.
If your pet is showing signs of illness compatible with bird flu virus infection and has been exposed to infected (sick or dead) wild birds/poultry, you should monitor your health for signs of fever or infection.
More Information
If you find a sick or dead bird, check with your state health department, state veterinary diagnostic lab, or state wildlife agency on their policy for collecting dead and testing sick or dead animals.
More
People Who Have Had Direct Contact with Infected or Potentially Infected Animals
During outbreaks of bird flu in wild birds and/or poultry, people who have had direct contact with infected or potentially infected sick or dead animals, including sick animals that might have eaten bird flu-infected birds, should monitor their health for fever and symptoms of infection.
Signs and Symptoms may include:
- Fever (Temperature of 100°F [37.8°C] or greater) or feeling feverish/chills*
- Cough
- Sore throat
- Difficulty breathing/Shortness of breath
- Conjunctivitis (eye tearing, redness, irritation, or discharge from eye)
- Headaches
- Runny or stuffy nose
- Muscle or body aches
- Diarrhea
*Fever may not always be present
Call your state/local health department immediately if you develop any of these signs or symptoms during the 10-days after your exposure to an infected or potentially infected animal. Discuss your potential exposure and ask about testing. If testing is recommended, isolate as much as possible until test results come back and/or you have recovered from your illness.
Additionally, close contacts (family members, etc.) of people who have been exposed to a person or animal with lab-confirmed bird flu viruses should also monitor their health for 10 days after their exposure for signs and symptoms of illness. If close contacts of people who have been exposed to H5 bird flu viruses develop signs and symptoms of illness, they should also contact their state health department.
Although exposure to sick or dead birds is the most common way that a pet might come in contact with avian flu, last week we looked at reports from Maine: Seal Deaths Linked To Avian H5N1, which warned beach goers not to approach - or allow their pets to approach - dead seals found along the shore.
In their latest update (July 8th) NOAA reports that the number of dead seals recovered has jumped from 57 to 88, and repeats the warning about approaching within 150 feet of a seal carcass.
If you see a sick, injured, or dead seal in Maine, please call the Maine Marine Animal Reporting Hotline at (800) 532-9551. To report seal strandings south of Maine, please call the NOAA Fisheries Stranding Hotline: (866) 755-6622.
The health risk posed by avian fluto the general public is low; however, precautions are recommended. Please do not touch live or dead seals, don’t allow pets to approach the seal, and observe the animal from a safe distance of 150 feet (safe for you and the animal).
