Insect-borne diseases occur in many parts of the United States. In New Mexico, 3 potentially fatal insect-borne diseases are of particular concern—West Nile virus, transmitted by mosquitoes, hantavirus, transmitted by the deer mouse and other rodents, and plague, a bacterial disease transmitted by ticks.

West Nile virus (WNV) was first detected in the US in 1999. Cases of WNV have occurred in New Mexico every year since 2003, declining each year from a high of 209 in 2003 to 8 in 2006. The virus is spread by mosquito bites. WNV is not spread person to person. Symptoms occur about 3 to 14 days after being bitten and range from mild to fatal. Mild illness symptoms include fever, headache, and body aches. The most serious consequence is fatal encephalitis or inflammation of the brain. Symptoms of a serious West Nile virus infection include high fever, stiff neck, muscle weakness, and disorientation. There is no specific treatment for WNV. Mild cases recover in a few days. Serious cases require supportive treatment which may include hospitalization, IV therapy, and respiratory support. The disease is more serious in the elderly. Avoiding mosquito bites is key to preventing WNV. Stay indoors at dawn and dusk when mosquitoes are most active, wear long pants and long sleeves, and use insect repellent. Use repellent containing 20-30% DEET for adults or 10% in children ages 2-12 years old. Soybean oil and eucalyptus oil containing repellents are effective alternatives but need to be reapplied more often. Windows and doors should have tight-fitting screens in good repair. Eliminate standing water around the home to control mosquitoes.

Hantavirus was discovered in 1993 in New Mexico. The virus occurs in most of North and South America, it is airborne, and without prompt medical treatment infection can be fatal. Hantavirus pulmonary syndrome (HPS) is the disease caused by hantavirus infection. Hantavirus is carried by rodents, specifically the deer mouse in the US. HPS has occurred in at least 30 of the 48 lower states. Rodents shed the virus in saliva, urine and droppings. People contract the disease by inhaling particles infected with the virus. HPS is an airborne infectious disease. The virus becomes airborne when particles dry out and get stirred into the air by sweeping or blowing dust. Symptoms begin 3 to 5 days after infection. These include coughing and shortness of breath. The disease progresses rapidly as the lungs fill with fluid, leading to respiratory distress. Medical attention must be given immediately, as the mortality rate is nearly 50% even with treatment. Reducing chance for exposure is the best prevention. If you suspect rodent contamination, wet the area with a disinfectant or 10% bleach solution. Call the state health department for instructions for clean up.

Plague is caused by bacteria carried by rodent fleas. About half of all cases of plague in the US occur in New Mexico. There are about 6 cases reported in New Mexico each year. Plague symptoms start 2 to 7 days after infection. Symptoms are sudden high fever, muscle aches and headache, chills, and extreme weakness. Plague can be cured with antibiotics, but treatment must be started as soon as possible. About 13% of plague cases in New Mexico are fatal. Preventative measures include avoiding contact with rodents and their nests and treating outdoor pets with flea control products.

References: http://www.health.state.nm.us/epi/documents/WNVbrochureEnglish.pdf, http://www.health.state.nm.us/epi/wnv.html, http://www.hantavirus.net/, http://www.health.state.nm.us/epi/plague.html.

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