The U.S. Department of Agriculture (USDA) last month confirmed that four black rats in Riverside County tested positive for bird flu for the first time.
“The discovery of H5N1 in rats in Riverside County demonstrates that the virus may be able to infect other types of animals beyond what we have been seeing in wild birds, poultry and cows,” Dr. Jennifer Chevinsky, Riverside County Public Health Officer, said in a statement to The Riverside Record. “We are working with local, state and national partners to closely monitor the situation and to better understand the transmission of H5N1 to animals.”
According to the report, the rats were collected in late January and tested positive for the virus in mid-February.
“The main reservoir of the virus, as far as we know, is still wild waterfowl like ducks and geese,” Maurice Pitesky, an associate professor in cooperative extension at UC Davis School of Veterinary Medicine, said. “And because they’re shedding so much virus, and because they’re potentially sharing habitat with all kinds of other species, the presence of the virus in rodents isn’t horribly surprising.”
Pitesky, whose research focuses on how the virus moves from water fowl to domestic poultry and other animals, said that rodent control is a huge issue on farms. So while health officials maintain that the risk to the general population remains low, Pitesky said the virus being found in rats creates yet another route for the virus to be introduced to dairy and poultry farms.
“That could be a significant challenge from a biosecurity perspective,” he said. “Poultry is the number one animal protein on the planet, so it could affect our ability to access poultry as a historically inexpensive source of animal protein.”
In a statement to The Record, USDA echoed Pitesky’s concerns.
“While there is no evidence to date of rodents transmitting the virus directly to other species, [bird flu] and other viruses may be carried from place to place as rodents transport wildlife feces and secretions onto equipment and into facilities,” the agency said. “Therefore, rodent control is a very important part of biosecurity efforts.”
But it’s not just farms that are impacted. Pitesky said backyard flocks can also have rodent problems and recommended that people tending to their own birds should take extra precautions like wearing surgical masks in addition to other personal protective equipment while working with their chickens.
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As of Friday, the Centers for Disease Control and Prevention (CDC) reported there have been 70 confirmed human cases of bird flu in the United States — 38 of which were in California. According to the CDC, there is currently no known transmission of the virus from person to person. The CDC did not return multiple requests for comment.
“There are no human cases of H5N1 in Riverside County at this time, and the risk to the general public remains low,” Chevinsky said. “In accordance with general disease prevention guidance, we continue to recommend avoiding direct contact or handling of rodents and their droppings.”
The Riverside County Department of Public Health recommends people take measures to both prevent and control rodent populations using a number of tactics that includes removing all shelter, food and water sources before attempting to control the rodent population.
“Trapping and chemical control alone will not achieve long term, permanent rodent control,” according to a pamphlet from the department. “If the rodents can be controlled and the conditions that allow them to reproduce are removed, then we have achieved a longer lasting control.”
According to an earlier news release about bird flu in the county, people can become infected with the virus by breathing in dust or droplets that have the virus, touching their eyes, nose or mouth with unwashed hands after touching contaminated surfaces or handling sick or dead animals or their environments and consuming raw unpasteurized milk or other dairy products.
Chevinsky said those who want to learn more or who are concerned about their risk of exposure to the virus in Riverside County can learn more about bird flu here on the Riverside University Health System — Public Health website.
Poultry owners with flocks that have experienced any unusual/suspicious illness or deaths should call the California Department of Food and Agriculture’s Sick Bird Hotline at: 866-922-2473.
This story has been updated to include comment from the USDA.
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