Taking Precautions Can Help Prevent West Nile Virus


                                                                                                                        Mosquito bites can be itchy and annoying, but if the bug that bites you is carrying West Nile virus, the consequences can be far worse.

Health and agricultural officials are urging homeowners to take steps this summer to prevent mosquitoes from breeding, to reduce the risk of spreading more West Nile virus, which can affect humans and other mammals. In its most extreme forms, the virus can lead to encephalitis, which is swelling of the brain; or aseptic meningitis, the swelling of the membrane around the brain and spinal cord.
Kim Mitchell, chief of rabies and vector-borne diseases at the Maryland Department of Health and Mental Hygiene, said there were 23 cases of humans infected with West Nile virus last year, up from 1 in 2009 and 14 in 2008. The cases last year all occurred in central Maryland , she said, including Baltimore, Anne Arundel, Howard and Montgomery counties, as well as Baltimore.
According to the DHMH database, the last time there was a human case of West Nile virus in Carroll was in 2003, when two people were infected. There were a total of 73 cases in the state that year.
Mitchell said the DHMH works in cooperation with several other state agencies to monitor the possible spread of West Nile virus. The state health department tests humans believed to be infected with the disease, the Maryland Department of Agriculture does surveillance of mosquito pools and livestock suspected of infection, and the Maryland Department of Natural Resources tracks the disease among wildlife.
While West Nile Virus can lead to serious health problems, the majority of people infected with West Nile virus will not experience any noticeable symptoms, Mitchell said. Usually less than 20 percent get a more serious form called West Nile fever.
“A lot of people tend to get West Nile fever, which is usually a mild, flu-like virus that does have fever but which tends to resolve itself in a matter of weeks or months,” she said. And less than 1 percent get a neuroinvasive form of the disease, she said, which may require hospitalization. These severe cases can lead to encephalitis or aseptic meningitis, which could have long-term health affects. “That involves a lot of fever and sometimes people are in a coma, however that’s a very small proportion of cases,” Mitchell said.
Of the 23 cases reported in Maryland in 2010, about 35 percent of them involved encephalitis, 39 percent involved aseptic meningitis, and 9 percent of them were recorded as West Nile fever, Mitchell said. While these numbers show a high number of serious cases, it’s most likely because the lesser forms of the virus often go undetected or unreported, she said. The MDA works with local governments to apply insecticide by air and ground to prevent the occurrence of mosquito-borne diseases. Since April, 140,000 acres have already been treated, according to a press release by the MDA.
Carroll does not receive any of the insecticide treatment, said Julie Oberg, a spokeswoman for the MDA. Counties have to sign a cooperative agreement to allow individual communities to participate in the MDA’s mosquito control program. Carroll County had signed the agreement in the past, Oberg said, but historically Westminster , Taneytown and Union Bridge were the only communities that expressed interest. 
“This year, MDA did not offer the program in Carroll and the other [western] counties as there was not enough participation to warrant the service, given our limited budget,” she said. The most important thing people can do to prevent the spread of West Nile virus is to prevent mosquito bites by using insect repellent or wearing long-sleeved shirts and pants, Mitchell said, and prevent pools of standing water from lingering because they can become mosquito breeding grounds.
“So many people have ornamental ponds, inflatable pools and bird baths that they forget all about, and pool covers covered with rain water,” she said. “It only takes a quarter of an inch of water to create a breeding ground for mosquitoes and mosquito larvae.”

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