[News article] New device provides chikungunya test results in an hour

New device provides chikungunya test results in an hour.

From the 11 May 2015 item at Entomology Today

By Ed Ricciuti

Scientists at a U.S. Army research center have modified an assay that tests whether or not a sample of mosquitoes harbors the virus responsible for the disease known as chikungunya (CHIKV), long a problem in the Old World tropics but recently established in the Americas.

…“Chikungunya” is a term used by people of the Makonde Plateau, between Tanzania and Mozambique, where the disease was discovered in 1952. It means, “that which bends up,” referring to the way arthritis caused by the disease crooks posture of the victim’s body. Symptoms of chikungunya can be as brutal as its name is to pronounce, although it is seldom fatal. Victims experience fever and pain and swelling of muscles and joints. Headache and rash may occur. The disabling impact can last for months.

Approximate distribution of Aedes aegypti (left) and Aedes albopictus in the United States, according to the Centers for Disease Control.

The chikungunya virus belongs to a group known as alphaviruses, at least 30 of which can infect humans and other vertebrates, causing diseases such as equine encephalitis and a variety of rash-accompanied fevers. CHIKV is transmitted by mosquitoes of the genus Aedes, chiefly Aedes aegypti, the bane of humans in the tropics because it also carries viruses responsible for yellow fever and dengue fever. Scientists have identified three different lineages — genetically-related groups — of CHIKV linked to geographical areas: Asia, West Africa, and East/Central/South Africa. All of the lineages exist outside the geographical areas after which they are named. A member of the Asian lineage, for example, has infected people in the Americas.

Like many tropical diseases, chikungunya has been rampant in the developing world for many years, but only became the focus of intensive research after it threatened western nations. An outbreak on Reunion Island, a French Department in the Indian Ocean, during 2005 and 2006 attracted attention largely because it’s a hot tourist destination for Europeans. Perhaps not by coincidence, the first transmission from mosquitoes in the Americans occurred in December 2013, on the French half of St. Martin, and island in the Caribbean. Reported cases in the Americas have now passed 1.5 million.

It began to show up in the United States during 2014, with nearly 2,500 cases reported from 46 states. Nearly all, however, were in travelers who picked up the infection in the tropics. Eleven people on the U.S. mainland, all in South Florida, contracted the disease directly from mosquitoes in the U.S.

During 2014, more than 4,500 people in Puerto Rico and the U.S. Virgin Islands were infected by mosquitoes, although the number may have been higher because chikungunya was not officially reportable to the federal Centers for Disease Control and Prevention until this year. There have been 77 chikungunya cases reported this year — as of April 7, from 21 states — but all were contracted out of the country.

To date, tests for CHIKV require expensive equipment in a laboratory setting and technicians who have undergone extensive training. Not so the dipstick test. It can be done on site by a neophyte and, importantly, does not require electricity. The dipstick involved is not the kind used to check oil in an automotive motor. It’s a small strip, usually paper-like nitrocellulose, a compound that is used in gunpowder, nail polish, laboratory filter paper, and other products. On the surface of the stick are reagents that will react to CHIKV antigens if the virus is present in the test sample, which is in a liquid solution.

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– Immuno-chromatographic wicking assay for the rapid detection of chikungunya viral antigens in mosquitoes (Diptera: Culicidae)

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Ed Ricciuti is a journalist, author, and naturalist who has been writing for more than a half century. His latest book is called Bears in the Backyard: Big Animals, Sprawling Suburbs, and the New Urban Jungle(Countryman Press, June 2014). His assignments have taken him around the world. He specializes in nature, science, conservation issues, and law enforcement. A former curator at the New York Zoological Society, and now at the Wildlife Conservation Society, he