Iowa State University entomologists warn travelers about Chikungunya virus


Aedes albopictus, pictured here, is one of two mosquito species associated with transmission of Chikungunya virus and has been documented in Iowa only a few times. The other species known to transmit the disease has never been cataloged in the state. Photo by Paul Airs. Larger image.

AMES, Iowa – Iowa State University entomologists said the two mosquito species that carry the Chikungunya virus are exceedingly rare in Iowa, but anyone traveling to the Caribbean or other affected areas should take precautions to avoid mosquito bites.

Chikungunya (pronounced chik-un-GUHN-ya) virus is transmitted from mosquitoes to humans and causes symptoms such as fever and intense joint pain. The first locally acquired case of the virus in the United States surfaced this week in Florida, according to the Centers for Disease Control and Prevention. More than 350 cases had been diagnosed previously in Americans who traveled to affected regions. But this week’s confirmation of the disease in a U.S. resident who hadn’t recently traveled has prompted a heightened awareness of the virus in the United States.

Outbreaks of the virus have occurred previously in Europe, Africa, Asia and the Caribbean.

Of the two mosquito species most closely associated with the virus, one has never been identified in Iowa, while the other has been cataloged only a handful of times, said Lyric Bartholomay, an associate professor of entomology and director of the ISU Medical Entomology Laboratory.

Both species thrive in tropical and subtropical climates and are less suited to Iowa’s moderate temperatures and weather, Bartholomay said.

“Based on our current understanding of mosquitoes that are involved in Chikungunya virus transmission and the distribution of those species in the U.S., the risk of transmission of the virus by mosquitoes in Iowa is low,” she said.

Bartholomay said the two species most associated with Chikungunya virus worldwide are Aedes aegypti, also known as the Yellow fever mosquito, and Aedes albopictus, known as the Asian tiger mosquito.

Traps located across the state and monitored by the medical entomology lab have never captured an Aedes aegypti specimen. A few specimens of Aedes albopictus have turned up since one was documented in Story County in 1999. Two specimens were cataloged in Scott County in 2000 and 2001, and a single female specimen was cataloged in Polk County in 2009.

Such limited sightings indicate that these species have not settled in Iowa, Batholomay said.

But that doesn’t mean Iowans shouldn’t pay attention to the virus. That’s especially true for Iowans who plan to travel to the Caribbean or any other region that has experienced outbreaks, she said.

While most patients recover from Chikungunya virus within a week, some continue to experience symptoms for months. Infants and seniors run the highest risk for severe and prolonged symptoms, according to the CDC.