Florida Mosquitoes Highly Susceptible to Transmitting Chikungunya Virus

Researchers in Florida are measuring the susceptibility to infection and transmission in Florida mosquitoes that are capable for transmitting viruses such as Zika, dengue, and chikungunya. Aedes aegypti and Aedes albopictus are 2 mosquito species that were analyzed in an evaluation conducted by scientists at the University of Florida (UF), which focused on "the ability of Florida mosquitoes to transmit chikungunya," according to a press release on the study.

Chikungunya first emerged in Africa in 1952. The illness can cause severe joint and muscle pain and has the capacity to lead to chronic rheumatoid arthritis.

The two mosquito species known for transmitting the virus are Aedes aegypti, which thrive in tropic and subtropic environments, and Aedes albopictus, which thrive in temperate and subtropic environments. Florida, however, possesses environmental factors that make it a viable habitat for both species, and therefore, it is a high-risk location for diseases transmitted by these mosquitoes, such as chikungunya. Between 2014 and 2016, there were more than 3800 cases of imported chikungunya fever in Florida, highlighting the great potential for local mosquitoes to be infected.

The researchers contrasted their analysis of the susceptibility to infection and transmission for the Florida Aedes aegypti and Aedes albopictus with results from a study of Aedes aegypti from the Dominican Republic. The research team, comprised of individuals from the UF Institute of Food and Agricultural Sciences (UF/IFAS), focused their research on 2 emerging strains of chikungunya, referred to as the Asian and Indian Ocean strains.

The Asian and Indian Ocean strains of the virus are relatively young; the Asian strain only appeared in 2013—one year before the outbreak in the Americas. The Indian Ocean strain caused a large outbreak in the Indian Ocean from 2004 to 2006, affecting about 1.5 million people.

"These are emergent strains that are associated with expanding geographic range, and an increase in the number of human cases." said Barry Alto, PhD, an associate professor of entomology at UF/IFAS, in the press release.

The researchers found that both species had high rates of susceptibility for infection and accelerated transmission for both relevant strains. In addition, they found that the saliva of the mosquitoes exhibited high susceptibility rates. This is important to know because saliva is the first point of contact with a human body when a mosquito bites human flesh.

Other important findings include the fact that Aedes albopictus exhibited higher rates of infection and transmission of the Indian Ocean strain immediately after ingesting infected blood. "Aedes aegypti had higher body infection and saliva infection later during infection with the Asian strain of chikungunya virus than Ae. albopictus,” according to the study. The researchers also concluded that, over time, both species experienced sharp declines in transmission and infection rates.

The information gleaned from the evaluation " can provide useful measurements that can be used in risk assessment by scientists as they model chikungunya transmission," according to the press release. Outbreaks of the illness are difficult to predict; however, because the presence of Aedes albopictus or Aedes aegypti does not necessarily mean that either strains of the virus are present. Both species of mosquitoes are commonly found in areas across the United States that have not, thus far, experienced any outbreaks; however, individuals should still ensure they are taking preventive measures to avoid mosquito-borne illnesses, such as wearing protective clothing, eliminating standing water, and wearing insect repellant.