The Connecticut Agricultural Experiment Station in New Haven has been keeping an eye on two problem pests that can spread disease, ticks and mosquitoes, and 2017 has seen a bumper crop of both. Ticks and their several pathogens Last year was a big year for Lyme disease in this area. The Connecticut Department of Public Health counted 31 confirmed cases in Wallingford, 20 in Meriden, 19 in Cheshire, and 12 in Southington. By the end of last summer, Goudarz Molaei, a research scientist at the agricultural station, was predicting that this year’s tick population would be bigger. He was right. Lyme disease is spread by ticks, and the station has been finding more Lyme-infected ticks this year. Their abundance is “unprecedented,” he said.The station’s Center for Vector Biology and Zoonotic Diseases collects ticks daily from residents, physicians and the Department of Public Health, and tests them for pathogens. Those ticks are now carrying pathogens that cause babesiosis and anaplasmosis at rates that are “relatively high,” in addition to Lyme. Babesiosis has an infection rate in ticks of 8 to 10 percent, and anaplasmosis 5 percent. Lyme disease has a 32 percent infection rate. In Connecticut, 40 percent of all ticks are infected with at least one pathogen. That puts residents who are routinely exposed to tick bites at greater risk.Why is this happening now? Warmer winters, longer summers, and plenty of animal hosts for the ticks, the experts say. Ticks now survive the winter and have a longer warm season to thrive — and reproduce. They infest, and feed on, small mammals, then pass their pathogens on to other hosts, including deer and people. What can people do? Residents are advised to keep deer and rodents away from their homes; wear long pants and long-sleeve shirts; use insect repellent; and perform a thorough tick check on children and pets. Mosquitoes and West Nile virus At the same time that ticks are on the rise, the agricultural station is also tracking a “rapid build-up” of mosquitoes carrying the West Nile virus. They have been found this year in 20 towns, mainly in the southern half of the state — including Branford, Guilford, Middlefield, New Haven, North Branford and West Haven — but also as far north as Farmington and South Windsor. Hartford County is new territory for these pests, according to scientists.Fortunately, there have been no reported human or horse cases of West Nile virus and associated illnesses acquired in Connecticut so far this year. Since 2000, 131 human cases of the illness have been reported in Connecticut, including three fatalities.Why is this happening now? Again, climate warming and an abundance of animal hosts. What can people do? Scientists say residents should use mosquito repellent and cover bare skin, especially at dusk and dawn. While cooler weather is on the way, it is too soon to stop taking precautions against ticks and mosquitoes. Both are pests, and both are dangerous.