Mosquito up close

Mosquito up close

Evolve Direct Primary Care Urgent Care reviews recent health alerts regarding chikungunya virus. According to an article published September 23 in the Annals of Internal Medicine, the Chikunguya virus has spread and established a firm foothold in the Western Hemispherse, specifically the Caribbean and Central and South America.

“We expect to see West Nile virus cases each year because it is established in Maryland, but we are also looking for imported mosquito-borne diseases in Maryland residents,” Dr. Katherine Feldman, Maryland public health veterinarian, said in a statement. “Maryland residents returning from a visit in the Caribbean who experience fever should seek medical care and make their provider aware of their recent travel.” according to an article published in the Baltimore Sun in June 2014. 

Symptoms include high fevers, rash and incapacitating joint pains. Although for most people symptoms clear up within 7-10 days, there are cases where they have persisted for months or even years in certain people. No licensed treatments or vaccines exists.

Doctors are particularly concerned that the stage is set for continued epidemic and high attack rates for the following reasons:  (1) people of the Western Hemisphere are “immunologically naive”, meaning we have never bee exposed previously,  (2) The main mosquito that carries this virus is very prevalent in the US and importantly, (3) travel to the Caribbean, Central and South America is frequent and prevalent amongst US residents.

Chikungunya virus is transmitted by a type of mosquito (A aegypti) which bite during the day and inside houses, differing from West Nile mosquitoes. According to Scott Weaver, PhD, director of the Institute for Human Infections and Immunity, these mosquitoes have closer associations with humans than West Nile mosquitoes.

Mosquitoes represent significant risk for travelers and now residents of the US

Mosquitoes represent significant risk for travelers and now residents of the US

Chikungunya has been endemic to Tanzania since at least the 1950’s but the first cases was not seen in the Western Hemisphere until 2013 where it emerged in the Caribbean. It has quickly spread to nearly every island with most cases having been identified in Haiti and the Dominican Republic. The Pan American Health Organization announced on September 5, 2014 there had been 8210 confirmed cases with 37 deaths.

Within the continental United States, there have been 751 cases of chikungunya with local transmission in south Florida. Robert Lanciotti, PhD, chief of the Diagnostic and Reference Laboratory in the Arbovirus Diseases Branch at the Centers for Disease Control and Prevention, Fort Collins, Colorado stated “I do not think that chikungunya will become established in the northern hemisphere. I think it will closely follow the pattern of dengue virus.”  “With only a few exceptions in recent history, we have only isolated imported cases [in the United States,] and dengue is not endemic.” Other areas within the US that could become a concern would be the Texas-Mexico border.

“The most important way to protect yourself from chikungunya is to keep mosquitoes out of your house. Here in the US, the main reason we don’t think we’re going to see major outbreaks is because people air condition their houses, or at least have screens that keep mosquitoes out,” Dr. Weaver explained. He added that draining areas of standing water is also important because that is where the mosquito larvae live.

Chikungunya is an RNA virus in the Alphavirus genus of the Togaviridae family, initially described in an epidemic in Tanzania (formerly southern Tanganyika) among the Makonde tribe (2). The name originated from a Kimakonde word meaning “that which bends up” or “to be contorted.” Since the first description of chikungunya in the 1950s, outbreaks have occurred in West Africa, the Indian Ocean, India, and Southeast Asia. There are 3 major geographically defined viral lineages: West African; East, Central, and South African (ECSA); and Asian.