Officials: Don’t help deer gather in killer outbreak
A deadly disease that causes internal hemorrhaging is sweeping through the deer population in California, including several Bay Area counties where people have spotted drooling animals suffering from seizures and gripped by vomiting and diarrhea, wildlife veterinarians said Thursday.
The outbreak, called adenovirus hemorrhagic disease, has been confirmed in Napa, Santa Clara, Sonoma, Tehama and Yolo counties, but it may well have moved into other areas, said Brandon Munk, senior wildlife veterinarian for the California Department of Fish and Wildlife.
There is no cure or vaccine for this disease, which spreads most rapidly in areas where deer come in close contact with each other. That includes locations where citizens feed the animals, a practice Munk said is illadvised and illegal.
“Providing attractants for deer — food, salt licks or even water — is against the law for good reason,” said Munk, who works in the department’s Wildlife Investigations Laboratory, in Rancho Cordova (Sacramento County). “Because these artificial attractants can congregate animals and promote the spread of disease, it’s particularly imperative to leave wildlife alone during an outbreak.”
Reports of dead and dying deer first began in May in the Bay Area and around Northern California. Necropsies confirmed the deaths were being caused by cervid adenovirus 1, or CdAdV1.
The virus, which does not infect people, pets or livestock, attacks the cells that line the blood vessels, causing hemorrhaging in the lungs and the gastrointestinal tracts of deer. Munk said the contagion can infect deer, elk and other cervids, but blacktailed deer appear to be most susceptible.
“It is very bad in blacktail deer fawns,” he said. “There is a high mortality rate in fawns.”
The CdAdV1 virus is wellknown in California. A huge outbreak in 199394 killed blacktailed and mule deer in at least 18 California counties. It has since been identified as the culprit in numerous, but sporadic, outbreaks going back to the 1980s.
“We don’t know why it chooses to rear its ugly head one year and not other years,” Munk said. He said it is way too early to tell if this outbreak will be as bad as the one in the 1990s, but “I’ve been here five years and it’s the most active adenovirus summer I’ve seen.”
Sick deer foam at the mouth, regularly regurgitate and have diarrhea. The sickest animals have seizures and are often found dead near water, where they apparently go to quench an excessive thirst.
Munk said the best way to deal with the disease is to limit the spread by eliminating reasons for deer to congregate. He said people can also help wildlife veterinarians track and study the disease by reporting sightings of sick or dead deer.