Monday, August 27, 2012
Health Care and West Nile Virus
According to eDocAmerica, over the past decade, the incidence of West Nile virus disease (WNV) was highest in 2006 when 4,269 cases were reported with 177 deaths attributed to this illness. This year, a total of 693 cases of WNV have been reported to the Centers for Disease Control (CDC), resulting in 26 deaths. While these numbers are lower than in 2006, it's important to know that the number of cases of WNV reported so far this year is the highest reported through the second week of August, 2012. Almost certainly, the country can expect to see more infections and deaths from this potentially preventable disease.
According to the National Institutes for Health (NLH), West Nile virus was first identified in 1937 in Uganda in eastern Africa. It was first discovered in the United States in the summer of 1999 in New York. Since then, the virus has spread throughout the United States. The West Nile virus is a type of virus known as a flavivirus. Researchers believe West Nile virus is spread when a mosquito bites an infected bird and then bites a person.
Mosquitoes carry the highest amounts of virus in the early fall, which is why the rate of the disease increases in late August to early September. The risk of disease decreases as the weather becomes colder and mosquitoes die off. Although many people are bitten by mosquitoes that carry West Nile virus, most do not know they've been exposed. Few people develop severe disease or even notice any symptoms at all. Risk factors for developing a more severe form of West Nile virus include:
• Conditions that weaken the immune system, such as HIV, organ transplants, and recent chemotherapy
• Older or very young age
West Nile virus may also be spread through blood transfusions and organ transplants. It is possible for an infected mother to spread the virus to her child through breast milk.
According to the CDC, prevention measures consist of community-based mosquito control programs that are able to reduce vector populations, personal protection measures to reduce the likelihood of being bitten by infected mosquitoes, and the underlying surveillance programs that characterize spatial/temporal patterns in risk that allow health and vector control agencies to target their interventions and resources. The easiest and best way to avoid WNV is to prevent mosquito bites.
• When you are outdoors, use insect repellent containing an EPA-registered active ingredient. Follow the directions on the package.
• Many mosquitoes are most active at dusk and dawn. Be sure to use insect repellent and wear long sleeves and pants at these times or consider staying indoors during these hours.
• Make sure you have good screens on your windows and doors to keep mosquitoes out.
• Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets and barrels. Change the water in pet dishes and replace the water in bird baths weekly. Drill holes in tire swings so water drains out. Keep children's wading pools empty and on their sides when they aren't being used.
How do humans contract this illness? According to eDocAmerica, most often, WNV is spread by the bite of a mosquito that has fed on an infected bird. Over 300 species of birds have been found to be infected with the West Nile virus including common songbirds, crows, blackbirds, bluejays, doves, and pigeons. Once a bird becomes infected, a mosquito can then transfer the virus from the bird's blood stream to humans, setting the stage for the infection. In a very small number of cases, WNV also has been spread through blood transfusions, organ transplants, breastfeeding and even during pregnancy from mother to baby.
What Are the Symptoms of WNV? Four out of five individuals who are infected with WNV will have no symptoms at all. Twenty percent of those infected will develop West Nile Fever which is characterized by mild fever, headache, and body aches, nausea, vomiting, swollen lymph glands and/or a skin rash on the chest, stomach and back. Less than 1% of those infected will develop a serious form of the disease associated with inflammation of the brain and spinal cord. This is known as West Nile Encephalitis or West Nile Meningitis. Symptoms of these include severe headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis.
How is WNV Infection Treated? As with most viral illnesses, there is no specific treatment available for WNV infection. Fortunately, most people recover from the illness in a few days to weeks without complications. In the more serious cases, hospitalization is usually required for supportive treatment such as intravenous fluids and assistance with breathing. In these individuals long-term problems may develop such as seizures, memory loss, personality changes, paralysis, tremors, and walking or balance problems. As previously noted, in a small percentage of cases, the infection can be fatal.
Much more information about WNV and its overall health care problems can also be found at this site: http://www.cdc.gov/ncidod/dvbid/westnile/wnv_factsheet.htm .
Signs of West Nile Virus infection are similar to those of other viral infections. There may be no specific findings on a physical examination, according to the NLH. However, up to half of patients with West Nile virus infection may have a rash. Tests to diagnose West Nile Virus include:
• Complete blood count (CBC)
• Head CT scan
• Head MRI scan
• Lumbar puncture and cerebrospinal fluid test (CSF)
The most accurate way to diagnose this infection is with a serology test, which checks a blood or CSF sample for antibodies against the virus. More rapid techniques using polymerase chain reaction (PCR) may be used. Because this illness is not caused by bacteria, antibiotics do not help treat West Nile virus infection. Standard hospital care may help decrease the risk of complications in severe illness. More details can be found at this website: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004457/ .
According to the Mayo Clinic, to reduce your own exposure to mosquitoes:
• Avoid unnecessary outdoor activity when mosquitoes are most prevalent, such as at dawn, dusk and early evening.
• Wear long-sleeved shirts and long pants when you go into mosquito-infested areas.
• Apply mosquito repellent with DEET to your skin and clothing. Choose the concentration based on the hours of protection you need — the higher the percentage (concentration) of the active ingredient, the longer the repellent will work. Avoid using DEET on the hands of young children, in case they put their hands in their mouths, or on infants under 2 months of age. When outside, cover your infant's stroller or playpen with mosquito netting.
A vaccine is available to protect horses from West Nile virus. No vaccine is available for humans, but work to develop a human vaccine is under way. More details can be found at this site: http://www.mayoclinic.com/health/west-nile-virus/DS00438 .
West Nile Virus can be deadly. During the summer and early fall, protect yourself from this disease. If you feel that you may be exhibiting symptoms, visit your doctor right away. If you have friends or family with immune disorders that may put them at risk, do everything possible to keep them safe from harm. Mosquitoes normally are a minor irritation, but with WNV, you cannot afford to take the risk. Use common sense when you are outside, and keep your indoors protected as well. After all, you don’t want to be the next WNV story on the evening news.