Zika, Lyme Drive Boost In US Bug-Borne Illnesses

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Diseases transmitted by ticks, fleas, and mosquitoes are becoming more unsafe and far more numerous: Between 2004 and 2016, they tripled to almost 650,000 cases, a new CDC report finds.

From 2004 to 2016, diseases from mosquitoes, ticks, and fleas tripled.

"Among the diseases on the list that are caused by indigenous pathogens are Lyme disease (Borrelia burgdorferi); West Nile, dengue and Zika virus diseases; plague (Yersinia pestis); and spotted fever rickettsioses", they wrote. "And we don't know what will threaten Americans next", said CDC Director Robert R. Redfield, M.D. State and local health departments and vector control organizations are the nation's main defense against this increasing threat.

Data have shown that Zika, once thought to be a benign virus, has caused numerous birth defects in the U.S. Zika and West Nile, which has caused epidemics since it was first introduced in the U.S.in 1999, were the most commonly reported mosquito-borne diseases in the continental U.S. During that period, a total of more than 640,000 cases of these diseases were reported to the CDC.

Some 96,075 diseases caused by such bites were reported in 2016, up from 27,388 in 2004, according to the CDC.

The nine new threats reported in the USA since 2004 include seven new tick-borne pathogens, including the Heartland and Bourbon viruses in the Midwest and a new Borrelia species - B. mayonii - that has caused Lyme disease in the upper Midwest.

For instance, chikungunya, a mosquito-borne virus, arrived in Puerto Rico in 2014 and Zika in 2015 - both probably carried by travelers.

In the time period covered by the study, nine new diseases showed up in the USA, including seven carried by ticks, and Zika and chikungunya, which are carried by mosquitoes. Only one vaccine is available against yellow fever, a mosquito-borne disease that hasn't been seen in the US but could show up again, according to the CDC report.

For example, rising temperatures will tend to expand the range of ticks farther north, thereby expanding tick season, "which puts people at risk for a longer time", Dr. Lyle Petersen, director of the CDC's Division of Vector-Borne Diseases, said at the news conference.

Taking steps to control ticks and fleas on pets.

Petersen said that federal programs are increasing funding for those organizations.

Nearly no state or local health department is fully prepared to manage these infections, the CDC said.

Recent research has suggested that Lyme disease alone strikes up to 300,000 Americans every year, as much as 10-times higher than the number of diagnoses actually made.

Auwaerter said the IDSA is investigating the role that climate change plays in the spread of vector-borne diseases "so that we can take appropriate actions to protect public health". The longevity, distribution, biting habits, and proliferation of the vectors all affect disease transmission, and, according to the report, they're all dependent on environmental factors such as rainfall, temperature, and shelter.

With added support, these agencies can better test for and track diseases and pests, train staff to conduct prevention and control activities, and educate the public on how to prevent bites, the researchers said.

"Zika funding helped prepare us for these types of diseases, but more funding is necessary", he said.

Rosenberg R, et al.

Rosenberg and co-authors disclosed no relevant relationships with industry.