By Jonny Lupsha, Wondrium Staff Writer
One species of Mosquito is responsible for spreading diseases like Zika. This species, Aedes aegypti, only makes up about 4% of the total mosquito population, but it’s a huge problem. Scientists hope to stop the spread by introducing modified mosquitoes.
The Florida Keys is about to become the pilot study for an unprecedented pest control idea. Scientists will perform a controlled release of genetically modified Aedes aegypti mosquitoes into the mosquito population. The genetically modified, non-biting male mosquitoes will mate with ordinary females and produce a generation of offspring whose females will not survive.
This population control effort isn’t just to stop Floridians from being itchy. Aedes aegypti are to blame for nearly all mosquito-to-human transmissible diseases, from Zika to yellow fever.
In her video series Food, Science, and the Human Body, Dr. Alyssa Crittenden, Associate Professor of Anthropology at the University of Nevada, Las Vegas, said that some illnesses like the mosquito-borne Zika are evidence of the third epidemiological transition in human history.
A Two-Front War
According to Dr. Crittenden, the second epidemiological transition of disease took place over the last two centuries and is characterized by an overall decline in infectious diseases, replaced by chronic degenerative diseases like diabetes and asthma. It began in the mid-1800s, but really took off in the 20th century.
“The third epidemiological transition is the emergence and reemergence of drug-resistant infectious diseases, things like Ebola and Zika,” she said. “It’s characterized by a resurgence of highly virulent infectious diseases that are affecting populations at a very large scale along with a suite of novel diseases. It’s timed from about the mid-1970s until now.”
Unfortunately, both the second and third epidemiological transitions are occurring in different parts of the world now. The second transition is often lifestyle-related, since, in addition to diabetes, it also includes illnesses like heart disease and high blood pressure.
“This [lifestyle] is one of minimal physical activity coupled with a diet that’s dominated by easy-to-access, highly processed, and energy dense foods,” Dr. Crittenden said. “Epidemiology is the study of disease patterns [and] our patterns of disease are intricately linked with our nutrition.”
From Species to Species
According to Dr. Crittenden, many of the diseases resurging in the third epidemiological transition are zoonotic, meaning that they are transmitted from animals to humans. Ebola, which saw a massive outbreak in West Africa in 2014, is one. However, the disease that scientists are focusing on in Florida is Zika.
“The disease was was first identified in monkeys in Uganda in 1947 and then in humans in 1952,” Dr. Crittenden said. “The first outbreak was in 2007 in Micronesia on the island of Yap.”
Although Aedes aegypti is the primary spreader of Zika, pregnant women can also pass it to their fetuses, which led the World Health Organization to urge pregnant women to avoid mosquitoes during the last major Zika outbreak.
“Children born with the virus have a birth defect called microcephaly, where their heads are considerably smaller than their counterparts without the virus,” Dr. Crittenden said. “They often have brains that aren’t fully developed; in severe cases, children with microcephaly also have issues with vision, speech, hearing, locomotion, and balance.
“There’s currently no vaccine, just as with Ebola, and research continues at a rapid pace in order to hopefully find prevention in the future.”