West Nile Virus is coming soon to a barbeque near you.
Colorado health officials diagnosed the first case of the season late last month in La Plata County. Infected mosquitoes have been detected in Arapahoe, Boulder, Delta, Denver, Larimer, Pueblo and Weld counties. Time to bust out the mosquito repellent. More importantly, dump the stagnant water out of the old tire swing or anyplace where it’s collecting in the yard. Mitigation is the only option until a better solution is found. Fortunately, that solution is on the horizon.
Meanwhile, we’re lucky not everyone bitten by a West Nile virus-infected insect will develop symptoms; only 20% will get the fever, aches, swollen lymph nodes, and rash associated with the pathogen, according to the Centers for Disease Control and Prevention. Of those who are infected, one in 150 will develop life-threatening neuro-invasive symptoms such as convulsions, inflammation of the brain and spinal cord, weakness, high fever, or paralysis. Although chances of dying from a West Nile Virus infection are less than 1%, the risk is higher among those over 60. Twenty people died last year from the disease.
The spring and summer showers that helped alleviate drought have also been a boon to pests. Female mosquitoes need two things to lay their eggs–stagnant water and blood. Males do not drink blood. While more water generally means more mosquitoes, it may also reduce West Nile virus transmission. When water is scarce, birds congregate at available watering holes where mosquitoes wait like tiny vampires to infect and be infected by the virus.
While all these @#$% bloodsuckers look the same to us victims, there are actually 3,000 species of mosquitoes around the world. Mosquitoes, not lions or sharks, are responsible for more deaths than any other creature. Sharks typically kill fewer than 10 people a year and get their own celebrity week of programming on television. Millions of people die every year from mosquito-borne pathogens such as malaria, encephalitis, yellow fever, dengue, Zika, chikungunya, and West Nile virus. Three groups of species (genus) are responsible for the majority of disease transmission – Anopheles, Aedes and Culex.
Colorado is home to just 20 species of mosquitoes, two of which — Culex pipiens and Culex tarsalis — carry the West Nile Virus. Unfortunately, spraying pesticides doesn’t just kill virus-carrying species. Non-target mosquito species and other insects perish, depriving birds, bats, amphibians, and other animals a food source. Pollinator populations also suffer. Moreover, mosquitoes can become resistant to pesticides.
Fortunately, a better solution is in the works that targets only disease-carrying mosquito species for elimination. Scientists genetically modify male mosquitoes of a targeted species so that female offspring are nonviable. When the males are released, they mate with ordinary female mosquitoes. Only male offspring survive and they carry the genetic modification for three generations. Gradually, modified mosquitoes replace natives.
A trial in Brazil found that this groundbreaking biotechnology eliminated 96% of the native population of Aedeas aegyti, the mosquito that carries dengue, yellow fever, chikungunya, and Zika, in neighborhoods where the modified males were released. That’s good news. A similar trial was completed in Florida after federal regulators cleared the biotechnology.
The U.S. Environmental Protection Agency approved the mosquito control method after determining that it would not impact other species since no animal depended on this one type of mosquito to meet its dietary needs. The agency concluded “the use of species-specific modified mosquitoes could reduce the use of pesticides for mosquito control. This may be especially beneficial for densely populated communities with environmental justice concerns. These communities could be at higher risk for exposure to mosquitoes, virus transmission, and exposure to pesticides from mosquito control.” This solution benefits both people and other species.
Genetic modification has such extraordinary potential to eradicate disease either indirectly as in this case or directly through the patient. Just this past month, a gene therapy restored a boy’s eyesight. We truly do live in an age of wonder.
Krista L. Kafer is a weekly Denver Post columnist. Follow her on Twitter: @kristakafer.
Sign up for Sound Off to get a weekly roundup of our columns, editorials and more.
To send a letter to the editor about this article, submit online or check out our guidelines for how to submit by email or mail.
