CONCORD - Public health officials are encouraging residents to take precautions against mosquito bites this season to prevent West Nile Virus (WNV) and Eastern Equine Encephalitis (EEE).

Mosquitoes already are out and the most likely time for them to spread disease is June through September.

Last year, nine batches of mosquitoes in the state tested positive for WNV, while none tested positive for EEE. In 2010, one animal and one person tested positive for WNV, and one animal was positive for Triple E.

“New Hampshire has been dealing with WNV since 2002 and with EEE since 2004, “ said Dr. Jose Montero, director of Public Health at the state Department of Health and Human Services, “and while the number of positive results has been decreasing of late, there is still a risk. It is therefore important that we remind residents that these diseases are preventable. It is essential that people follow precautionary steps, most importantly using an insect repellent, to avoid becoming infected by one of these diseases.”

Triple E and WNV are transmitted through the bite of an infected mosquito picked up by feeding on an infected bird. EEE carries a high mortality rate for those who contract its more serious form. Symptoms may include high fever, severe headache and sore throat. A stiff neck is also a symptom of the severe form of the disease, which can lead to seizures and coma. Symptoms usually occur 4 to 10 days after someone is bitten.

The risk of contracting WNV is low and in the overwhelming majority of cases there are no symptoms or just mild, flu-like symptoms. At times, the virus can cause meningitis and can be a serious threat to seniors, young children and those with compromised immune systems. The illness occurs usually within 3 to 15 days after the bite.

Health officials said residents should use an insect repellent containing DEET, picaridin, oil of lemon eucalyptus or IR3535 against mosquitoes; wear long-sleeve shirts and pants when outdoors at times mosquitoes are biting; remove standing water around homes where mosqitoes can breed such as in tires, flower pots or pool covers; make sure window and door screens fit tightly and have no holes; and tell your health care provider if you develop any symptoms of WNV or EEE.

For more information about the viruses or Lyme disease, visit the DHHS website at www.dhhs.nh.gov; the Centers for Disease Control and Prevention website at www.cdc.gov; or call DHHS Communicable Disease Control Section at 1-800-852-3345, ext. 4496.