The leadership of BLSG regularly mentions mosquito borne
diseases when describing the services they provide. Their message is that BLSG’s
operation reduces the chances that residents of the BLSG District will contract
a disease from a mosquito. The BLSG leadership’s message is wrong, and it is
inappropriate for them to even include this topic in public discussions.
Arboviruses in Vermont
Despite BLSG’s continued reference to a long list of
tropical diseases, there are only two arboviruses carried by mosquitoes in
Vermont: West Nile virus (WNV) and eastern equine encephalitis virus (EEEv).
The human illnesses caused by these viruses are extremely rare in Vermont.
Last month an article about the health effects of pyrethroid insecticides was published by the Journal of the American Medical Association (JAMA Internal Medicine). You can read a summary here and a news article here. The peer reviewed article describes the results of a study of 2116 nationally representative American adults who were followed for 17 years. At the beginning of the study each participant had a urine test for pyrethroids. During the study 246 of the participants died, and those with higher levels of pyrethroids at the start of the study were more likely to die. The group was divided into thirds (low, medium, and high levels of pyrethroids), and those in the high group were three times more likely to die from cardiovascular disease than those in the low group. Those in the high group were 1.5 times more likely to die of any cause compared to the low group.
Southern New England had a big year for Eastern Equine Encephalitis in 2019. There were 20 reported human cases of the EEE virus (EEEv) in Massachusetts, Connecticut, and Rhode Island with nine deaths. This is the most cases in a decade including the last outbreak year of 2012. To the east and west of Vermont, New Hampshire and New York had no human cases of EEEv, but dozens of mosquito samples were positive for EEEv. Vermont did not have any human cases of EEEv in 2019, and no EEEv was found in 3217 samples of mosquitoes tested.
There has been a lot of scary information about mosquito-borne diseases repeated by employees and board members of BLSG. There are two serious diseases carried by mosquitoes in Vermont, and one killed two people in 2012. That fact alone deserves our attention, but how much should we be concerned about these diseases?
Every week, the Centers for Disease Control and Prevention (CDC) releases a report on diseases, and last week’s report was about the rise in diseases spread by insects and ticks. This was a typically dry and technical report about trends between 2004 and 2016 in human cases of 16 diseases spread by ticks, mosquitoes, and fleas. The CDC also publicized this report at their Vital Signs site where the hype was cranked up by a dramatic video and some revealing graphs.
There is some very useful information in yesterday’s Rutland Herald article by Will Mathis, Director of Operations of the BLSG Insect Control District. So it was disappointing to see the group is still misleading residents about the risk of contracting the Zika virus from mosquitoes in Vermont. The article mentions that insect borne diseases are part of their justification for controlling mosquitoes, and then adds “Vermont has now recorded its first case of the Zika virus.”
The Vermonter with Zika did not get it from a mosquito bite in Vermont or anywhere north of Florida or Texas. That Vermonter had travelled to an area where Zika is present. Zika virus and the primary mosquito vector of the disease (Aedes aegypti) are not present in Vermont (more here).
Avoiding mosquito-borne diseases like West Nile virus is a primary motivation for mosquito control. Since it was first confirmed in the US in 1999, West Nile virus has infected more than 46,000 people in the US and more than 2,000 people have died. Mosquitoes infected with West Nile virus have been found in every Vermont county in past years, so this threat should not be ignored. However, between 1999 and 2016, only 12 cases of West Nile virus were reported in people in Vermont (Figure 1).