CDC finds mosquito- and tick-borne disease cases have tripled since 2004

STAMFORD — Warmer weather definitely has its upsides — sunshine, spring blooms and the urge to get outside and play — but it also brings a higher risk of exposure to tick-, flea- and mosquito-borne diseases.

A recently-released report from the Centers for Disease Control and Prevention shows number of people getting diseases transmitted by mosquito, tick and flea bites has more than tripled in the United States between 2004 and 2016. Additionally, since 2004, at least nine such diseases have been discovered or newly introduced here.

Though the CDC stopped short of suggesting that people cancel outdoor plans, health officials did emphasize the increasing importance of bug repellent to protect everyone — especially children — from outdoor pests.

Dr. Michael Parry, Chief of Infectious Diseases at Stamford Hospital, said it’s challenging to accurately track Lyme disease cases because not all cases are reported and the tests are not always reliable, but other tick-borne diseases have been on the rise for several years.

“It’s hard to know whether we’re seeing more Lyme … it is often unreported, but our overall impression of Lyme disease is that it is very prominent in this area, very underreported and it’s certainly not diminishing in number. And, in the last five or six years, we’ve seen relatively more babesia and anaplasma.”

Like Lyme, babesia and anaplasma are also transmitted by the deer tick. Babesia, Parry said, is an infection of the body’s red blood cells and its symptoms are similar to those of malaria. Anaplasma, he said, infects the white blood cells and causes a wide variety of symptoms such as fever, headache, chills, muscle aches and vomiting.

Data from the Connecticut Agricultural Experiment Station , which monitors mosquito and tick populations throughout the state and tests ticks for various diseases, shows the of number of ticks that tested positive for Lyme disease last year was more than double that of 2016.

A total of 5,577 ticks were submitted to the station in 2017 by residents, health department and physician’s offices across the state. Of those, the data shows 3,993 were tested for Lyme and other diseases, nearly a third of which (1,277) tested positive. Lyme was the most common disease detected, according to the data, but babesia and anaplasma were also prevalent.

A total of 297 ticks were submitted from the Stamford area, 86 of which tested positive.

Parry said there are likely a number of reasons as to why tick- and mosquito-borne diseases are on the rise.

“In our local area, it’s related to the increasing number of deer and the increasing growth of populations into previously wooded areas over time,” he said. “There are deer all over the place in Stamford, and that clearly is a risk factor for the increasing numbers of ticks.”

“It’s quite clear that climate change, in a global sense, has impacted the expansion of some of these insect-borne pathogens – like malaria and dengue,” Parry said. “Mosquito populations have grown in many areas in the world, and a lot of that is related to a rise in the average mean temperatures in many parts of the world that were once too cold for mosquitoes and ticks to thrive.”

Widespread travel and global importing and exporting are also factors, according to the CDC report.

CDC officials called for more support for state and local health departments, which are chronically underfunded. A recent survey of mosquito control agencies found that 84 percent needed help with such basics as surveillance and testing for resistance to pesticides, the New York Times reported.

Stamford has a task force – called the Health Department Vector Disease Prevention Task Force – which consists of city officials and employees, local health and recreation department representatives and staff from the agricultural station, and works to address mosquito and tick populations and provide information about disease prevention.

“This task force was put together so that we can make sure we’re hitting all the areas in the city that are affected with stagnant water, tall grass or garbage collections that could also attract insects,” said Ron Miller, Director of Environmental Inspections for the Stamford Health Department.

“One of the things that we are proactive in is when we get complaints of stagnant water, we respond to that site and if there’s a pooling of water, we larvicide that area to prevent mosquito larvae from hatching,” he said. “We also contract out with a company called All Habitat and they larvicide the catch basins – or storm drains – three times a year.”

The Connecticut Agricultural Experiment Station has three trapping sites within the city — at Cove Island Park, Sleepy Hollow Park in Springdale, and at the intersection of Intervale and Gaxton roads — where the group catches mosquitoes and identifies their type.

But, when it comes to addressing tick populations, there is little to be done.

“Preventing tick-borne diseases is largely a personal responsibility — using tick repellent, doing tick checks, wearing the proper clothing,” Parry said.

“Environmental tick control is really very difficult in areas where there are mice and deer because ticks are very difficult to kill,” he said. “You can’t spray for ticks the way you can for mosquitoes, so unless you have the mandate to eliminate the deer and mouse populations, then you’re going to have ticks. Really the only thing we can do, or the city can do, is educate the population about protecting themselves and their pets.”

If bitten by a tick, Jim Federici, Lab Director at the Health Department, said Stamford residents can submit the insect to the city lab. The health department the works with the agricultural experiment station in New Haven to identify the type of tick and test it for Lyme and other tick-borne diseases.

But, since roughly 30 percent of the ticks in Connecticut test positive for Lyme, Parry said he recommends his patients assume the tick is a carrier and seek treatment.

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