County Prepares for Summer of Disease
By E.A. Barrera

San Diego County officials have issued a series of warnings, directives and announcements in the past month, outlining preparations for potentially serious disease infestations in the region. Confirmation of outbreaks of the hantavirus, rabies, West Nile virus and dog flu have prompted County Health Department officials to warn residents about the problems associated with these diseases and what folks can do if they suspect they have encountered these health threats.

Hantavirus

County Vector Control confirmed three wild mice in the Tierrasanta area tested positive for the hantavirus. Hantavirus is carried by wild rodents, primarily deer mice. The virus, found in rodent droppings and urine, can be inhaled by humans when it becomes airborne. The airborne virus can cause Hantavirus Pulmonary Syndrome, a rare illness that can be fatal.

"The mice were trapped during routine Vector Control monitoring," said Gary Erbeck, director of the Department of Environmental Health. "It is important to eliminate rodent infestations immediately and avoid rodent infested areas. Do not stir up dust or materials that may be contaminated with rodent droppings and urine. Now is a good time to use caution while opening up cabins that have been closed for the winter."

The first signs of human illness caused by hantavirus are similar to flu symptoms. They include fatigue, fever, muscle aches, headache, dizziness, chills, nausea, vomiting, diarrhea and abdominal pain. Later symptoms of HPS include coughing, shortness of breath rapidly progressing to severe difficulty in breathing, and sometimes death. "While there is no specific treatment for hantavirus, there are ways to avoid exposure to the virus. Clean up rodent droppings and urine using the wet cleaning method," said Erbeck, who warned residents not to sweep or vacuum the dirty area. "Ventilate affected area by opening doors and windows for at least 30 minutes. Use rubber gloves. Spray a 10 percent bleach solution (two tablespoons bleach to one cup of water) onto dead rodents, rodent droppings, nests, contaminated traps and surrounding areas and let the disinfectant stand for at least 15 minutes before cleaning. Clean with a sponge or a mop. Place disinfected waste into two plastic bags, seal them and discard in the trash. Wash gloves in a bleach solution, then soap and water, and dispose of them using the same double-bag method. Thoroughly wash your bare hands with soap and water."

For more information on hantavirus, visit www.sdvector.com.

Rabies

The San Diego County Animal Disease Diagnostic Laboratory confirmed one bat found in Carlsbad on May 9 and two bats found in the San Pasqual Valley on May 19 tested positive for rabies. County officials said there was no known human or animal contact with the rabid bats, but they noted that these incidents brought the total to six bats confirmed positive for rabies since January. This compares to six bats and one skunk testing positive for rabies in 2005. The majority of rabid bats are found in summer and early fall.

According to the county, bats are beneficial in controlling insect populations and important to the ecology. Although the county diagnoses about 10 to 15 cases of rabies in bats each year, less than 1 percent of bats in the wild carry the rabies virus. Bats that come into contact with humans or animals are more likely to be ill and need to be tested for rabies.

"Rabies is a fatal disease that affects the nervous system of humans and other mammals. The rabies virus is carried in the saliva of infected animals and is usually transmitted to people and other animals when they are bitten or scratched by the rabid animal," said Dr. Gundula Dunne of the County Department of Health and Human Services. "On May 13, 2006, a 16-year old boy died in Texas after being exposed to rabies from a bat. Since 1990, most human rabies cases in the United States have been associated with unrecognized exposure to a bat. Bat bites are extremely small and difficult to recognize. And most people do not realize they have been bitten."

County officials warn that if you find a dead or sick bat, call your local animal control agency to have the bat picked up for rabies testing.

For more information on bats and rabies, visit http://www2.sdcounty.ca.gov/hhsa/documents/rabiesflyer 040904.pdf.

West Nile Virus

According to the County Department of Health, West Nile Virus season has arrived in San Diego and County Vector Control will use a helicopter to apply mosquito larvicide to local wetlands. The helicopter larvicide applications deliver a backpack blower larvicide application of granules and repellant. The county also introduces mosquito-eating fish into the region's waterways where mosquitoes breed. The insecticide eradicates mosquito larvae and adults, thus reducing mosquito breeding and the risk of the virus.

"Controlling mosquito breeding and eliminating backyard breeding sites are essential in preventing the spread of the West Nile Virus," said Chris Conlan, supervising vector ecologist with the county Department of Health. "Two birds have already tested positive for WNV in San Diego County this year. A dead scrub jay was found in Valley Center in February and a dead crow was found in Serra Mesa in May."

The aerial applications will occur monthly during the mosquito-breeding season at 39 key breeding areas, covering 875 square miles in the county. Officials insist the larvicide is not toxic to humans and does not pose a risk to wildlife or the environment.

Last year in San Diego County, there were no locally acquired human cases of West Nile virus, although 162 dead birds tested positive for the virus. Last year in the United States, 2,949 human cases were confirmed and there were 116 deaths.

Dog Flu

Two dogs at the Canine Companions for Independence kennel in Oceanside tested positive in the initial tests for dog flu. Additional tests to confirm the diagnosis are being performed at Cornell University, with results expected last month.

"CCI immediately started infection control measures, including quarantine of all exposed dogs. The dogs do not pose a risk to the general community," said CCI Director of Canine Programs Paul Mundell. "CCI working assistance dogs and puppies seen in public have not been exposed."

According to county health officials, there is no evidence that humans can be infected with this type of flu. The county reported that the first dog became ill with symptoms of coughing and sneezing on May 20. Out of the 65 dogs in the kennel, 64 were affected.

"Although test results are not yet available for all dogs, all sick and exposed dogs have been isolated to prevent spread of the disease. Fortunately, all sick dogs are expected to fully recover, and none have died or required hospitalization. A dog from Colorado is suspected to be the source of the outbreak," Mundell said.

Severe cases of dog flu can develop into pneumonia that can require hospitalization and intensive care. The fatality rate is very low and estimated to be 1 percent to 5 percent. There is no vaccine for canine influenza.

"Dog flu, also called canine influenza, is an emerging viral disease causing respiratory infection in dogs," said County Public Health Veterinarian Dr. Gundula Dunne. "Dog flu is similar to the common disease called kennel cough. Dogs with a mild form of dog flu have a cough, nasal discharge and mild fever that last for 10 to 21 days. The virus is spread by aerosolized respiratory secretions, contaminated inanimate objects, and even by people moving back and forth between infected and uninfected dogs. Pet owners are encouraged to call their veterinarians if their dog develops a cough. Dogs that are coughing should not be taken to locations where they may have contact with other dogs and pet owners should also always wash their hands after handling a sick dog."