MANCHESTER, N.H. – City health officials are stepping up their mosquito surveillance, particularly in the northwest part of town, where a dead crow tested positive for Eastern equine encephalitis.

Deputy Public Health Director Rich DiPentima said the bird was found Monday and sent to the state for testing. The results came back Tuesday night.

DiPentima said there’s no way to know if the bird contracted the disease from mosquitoes in Manchester or another part of the state. He said it is the first time a bird found in the city has tested positive for the disease.

Like West Nile virus, Eastern equine encephalitis is transmitted through an infected mosquito’s bite. It has not yet been found in a New Hampshire human.

Last week, state health officials said a dead raven in Concord was stricken with the condition.

Unlike the crow, the raven was confined. That means mosquitoes may be carrying the disease in a wider area, said DiPentima.

Human cases of the disease are relatively rare. Last year, two Massachusetts residents died after becoming infected.

DiPentima urged citizens to wear insect repellant when outdoors and clear any standing water from around their homes that could serve as breeding areas for mosquitoes.

DiPentima said symptoms for West Nile virus and Eastern equine encephalitis are similar: high fever, stiff neck, severe headache and sensitivity to light. He said Eastern equine encephalitis is the more serious disease of the two.