C.D.C. officials called for more support for state and local health departments. Local agencies “are our first line of defense,” said Dr. Robert Redfield, the new director at the agency, which is facing its own deep budget cuts. “We must enhance our investment in their ability to fight these diseases.”
Although state and local health departments get brief infusions of cash during health scares like the Zika epidemic in 2016, they 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, Dr. Petersen said.
[READ: Tips for Protecting Yourself Against Mosquitoes and Ticks]
Between 2004 and 2016, about 643,000 cases of 16 insect-borne illnesses were reported to the C.D.C. — 27,000 a year in 2004, rising to 96,000 by 2016. (The year 2004 was chosen as a baseline because the agency began requiring more detailed reporting then.)
The real case numbers were undoubtedly far larger, Dr. Petersen said. For example, the C.D.C. estimates that about 300,000 Americans get Lyme disease each year, but only about 35,000 diagnoses are reported.
The study did not delve into the reasons for the increase, but Dr. Petersen said it was probably caused by many factors, including two related to weather: ticks thriving in regions previously too cold for them, and hot spells triggering outbreaks of mosquito-borne diseases.
Other factors, he said, include expanded human travel, suburban reforestation and a dearth of new vaccines to stop outbreaks.
More jet travel from the tropics means that previously obscure viruses like dengue and Zika are moving long distances rapidly in human blood. (By contrast, malaria and yellow fever are thought to have reached the Americas on slave ships three centuries ago.)
A good example, Dr. Petersen said, was chikungunya, which causes joint pain so severe that it is called “bending-up disease.”
Lyme Handbook 