Three horses contracted West Nile Virus this summer in Connecticut. Two died. One of the two was stricken on the Danbury-Bethel border. The other two horses were from Hebron and Milford. So it is clear now that the West Nile Virus threat is advancing through both the geography of the state and the taxonomy of species. The threat isn’t just to crows living in Fairfield County anymore. Higher mammals – most notably our favorite higher mammals, humans – are now in the crosshairs of this disease.

 The death of the horse in Danbury has spurred a more aggressive attack on the mosquitoes that carry the virus. An insecticide spraying program was initiated in Danbury and Bethel this week, and here in Newtown, health officials are renewing the application of larvicide in catch basis where standing water spawns legions of mosquitoes. Additionally, state agencies including the Department of Environmental Protection and the Connecticut Agricultural Experiment Station, and the Department of Public Health are coordinating efforts to track West Nile Virus as it migrates through the state. They are also working to formulate strategies to thwart the progress of the disease on the wings of its most efficient carrier, the mosquito.

The one positive note in the chorus of bad news that has been reported on the West Nile Virus scare is that most humans are extraordinarily resistant to the disease. During last year’s outbreak of the disease in New York City, representatives of the Centers for Disease Control and Prevention (CDC) went door-to-door in Queens drawing blood samples from the residents there to test for antibodies to the disease. The survey showed that as many as 1,900 people, or 4 percent of the tested population, may have had the disease but suffered few, if any, ill effects.

It is quite possible that there are people in Connecticut, even people in Newtown, who have already been infected with West Nile Virus and just don’t know it. Unfortunately, what we don’t know will hurt those of us who have weakened or damaged immune systems. The disease thrives in people whose natural defenses are lowered, causing a full range of flu-like systems. In severe cases, it causes encephalitis, or swelling of the brain, and death.

It is now time for the state to take the obvious next step: initiate a survey by the CDC testing the blood of humans living in the areas where the virus has established itself, including the Danbury-Newtown area. Such a survey would help determine the risk of infection to humans and alert local health officials to the need for precautionary measures for the elderly, infants, and others whose immune systems are weak.

The evidence is clear that West Nile Virus is spreading throughout Connecticut in mosquitoes, in birds, and in livestock. Do we really need to wait for the inevitable evidence of infection in humans before our health officials start collecting the data they need to track and to develop strategies to prevent the unchecked spread of this virus through the state’s population?