City officials are urging residents to take common-sense precautions after two mosquitoes in Haverhill tested positive for West Nile virus. The mosquitoes were found in the Upper North Avenue area, near the large National Grid gas tank and by the animal shelter on Primrose Street. Although no human cases have been discovered and no cases of the more serious virus, Eastern equine encephalitis, have been detected in Haverhill mosquitoes, the mayor has ordered spraying as a precaution. West Nile virus and Eastern equine encephalitis are mosquito-borne viruses that can cause fever, meningitis, or encephalitis. Early symptoms of these diseases include fever, headache, stiff neck, and muscle weakness. All outdoor recreation activities for both the schools and the Recreation Department have been rescheduled so that no outdoor activities occur between dusk and dawn. Residents are urged to avoid going outside after dusk, particularly in areas likely to have mosquitoes. If you must venture outdoors, use a mosquito spray containing DEET (except on young infants). In addition, any standing water should be removed. For more information, contact the city’s Health and Inspectional Services Department at 978- 374-2325.