Published: Wed, May 02, 2018
Medical | By

CDC: Diseases from mosquito, tick, flea bites more than tripled from 2004

CDC: Diseases from mosquito, tick, flea bites more than tripled from 2004

The report notes an increasing trend in these diseases each year, whereas the burden of mosquito-borne diseases appears to be more episodic, with numbers fluctuating as epidemics occur.

Tick-borne diseases alone more than doubled during that time frame, and accounted for more than 3 of every 5 cases of insect-transmitted disease in the United States. These diseases are spread as mosquitoes expand into new territory and are brought home by travelers.

Tick-borne diseases and mosquito-borne diseases also seem to follow different patterns. "And we don't know what will threaten Americans next".

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

The most common mosquito-borne viruses are West Nile, dengue, and Zika, while the most common disease resulting from the bite of an infected flea is the plague.

The number of vector-borne illnesses in the us tripled from 2004 to 2016, rising to almost 650,000 cases.

"Nine new germs - seven of them spread by ticks - have been newly introduced or discovered in the United States since 2004", he added.

Of the 642,602 total reported cases, more than 75 percent were caused by tick-borne diseases - most commonly, Lyme disease. Overall, more than 640,000 cases of these so-called vector-borne diseases were reported during the study period.

They include two previously unknown, life-threatening tick-borne viruses - Heartland and Bourbon - that were reported from the Midwest, and the chikungunya and Zika viruses transmitted by mosquitoes that were introduced to Puerto Rico in 2014 and 2015.


Lyle Petersen, director of the CDC division of vector-borne diseases, said increasing temperatures can help such diseases spread, though he declined to say specifically if climate change is the cause. 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.

Tick-borne diseases in particular are not reported or recognized, so it is hard to estimate their cost and burden, noted Lyle Petersen, MD, director, vector-borne diseases at the CDC, on a media call.

Widespread and hard to control, diseases from mosquito, tick, and flea bites are major causes of sickness and death worldwide. "Higher temperatures make mosquitoes more infectious", Petersen added. Warmer weather has also made tick and mosquito season longer, and mosquitoes tend to become more infectious during heat waves.

"Our nation is better prepared today than we were a year ago", Redfield said. "Second, CDC is working with state and local health departments to build or rebuild comprehensive vector programs that have eroded over time", he said.

Dr. Paul Auwaerter, president of the Infectious Diseases Society of America, urged Congress to increase funding "for surveillance and prevention of vector-borne diseases, including resources to support research on the most effective methods for preventing tick-borne infections".

Redfield, MD, said the growing public health problem will only worsen without "major improvement" in how local, state, and federal levels work together to track, report, and control the diseases.

"Vector-borne diseases such as Lyme disease and Zika virus disease can devastate patients and their families, causing significant suffering", he told Agence France-Presse.

Agencies can also train vector control staff on core competencies for conducting prevention and control activities.

Other factors, including an increase in global travel and more people living near wildlife, also affect the spread of these diseases, Petersen said.

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