Clearing up misconceptions about mosquito story


I’m writing to correct an erroneous statement in the story “Mosquitos continue to test positive for West Nile Virus” that ran in the Moab Times-Independent last week (8 August 2019). Near the end of the article is the sentence: “The transmission cycle, she said, is from bird to mosquito to bird – and sometimes humans.”

There are two things wrong with this statement:

First, humans are not in the transmission cycle of West Nile Virus; the disease is transmitted from bird to mosquito to bird to mosquito to bird…There is no cycle of WNV going from mosquito to humans and back to mosquitoes—the virus injected into a human in mosquito saliva cannot be picked up by mosquitoes biting that human to be carried to another host; humans are dead-end transfers for the virus.

Second, the reporter, Doug McMurdo, inserted the phrase “and sometimes humans” into the statement attributed to Libby Nance, manager of the Moab Mosquito Abatement District. Libby did not say this, she knows the details of how diseases move from hosts to mosquitoes, and which hosts are dead ends for the disease organism and which hosts can carry the virus ready to be transferred to another mosquito to complete the cycle.

I hope this clears up any misconceptions folks may have gotten from the article. To be clear, humans can and do get WNV from being bitten by a mosquito carrying the virus, but no matter how many times that infected person is bitten by mosquitoes after contracting the disease, no viral particles are transferred to the biting mosquitoes from the infected human.

Thank you for your patience with a very trying summer of mosquitoes.

– Tim Graham
Chair, Moab Mosquito Abatement District Board