Researchers have always wondered why mosquitos that carry malaria (Anopheles arabiensis) don't bite chickens. They have now discovered that the type of mosquito that causes malaria is repelled by chicken odor. And why should it not be? Chickens actively prey on mosquitos, as well as anything else that moves and fits into their mouths.
When researchers set up mosquito traps, many fewer mosquitos were caught in traps where a caged chicken was nearby. The researchers have even isolated the particular chemical on chicken odor that repels these kinds of mosquitos. These findings may lead to mass produced chicken odor insect repellants.
Malaria is an infectious disease caused by the bite of a particular mosquito. The signs start to appear anywhere from 8 to 25 days after the person becomes infected. Symptoms of malaria typically include fever, fatigue, vomiting and headaches. In severe forms it can cause yellow skin, seizures, coma, or death. In 2015 alone, there were 214 million cases of malaria reported worldwide, resulting in an estimated 438,000 deaths. Nine out of ten malaria deaths occur in Africa.
Despite the dire need in this major health crisis, no effective malaria vaccine yet exists, although certain medications are available. In many Asian countries, these medicines are substandard, if not flat out counterfeit. This causes many avoidable deaths. When properly treated, people with malaria can expect a full recovery. However, severe cases of malaria progress rapidly and cause death within hours or days. Cerebral malaria is one of the leading causes of neurological disabilities in African children.
Poverty can increase the risk of malaria, but malaria also causes poverty. The economic impact of malaria is said to cost Africa about 12 billion dollars every year. The slowness in producing a malaria vaccine might possibly have racial factors, as most of the people who most need the drug are located in Africa (i.e. non caucasian).
Despite global intervention efforts, malaria remains a major public health concern in sub Saharan Africa. The Anopheles arabiensis mosquito is an opportunistic feeder on all vertebrate hosts, especially outdoors, primarily using its sense of smell to detect and locate the host.
In field tests, the compounds derived from chickens included isobutyl, butyrate, napthalene, hexadecane, and trans-limonene oxide. These compounds, along with a number of generic host compounds, significantly reduced trap catches inside the house. Outdoors, these mosquitos randomly feed on pigs, sheep, and cattle (but not chickens). Indoors, they much prefer human meat. It seems, at first, like the solution is simple. Sub Saharan people should keep chickens. Unfortunately, in these poorest parts of the world, many people cannot afford to buy a chicken.
Does this mean when we go camping in the sub Sahara region, mosquitos won't bite us if we cook chicken over a campfire? Or does it have to be the odor of a live chicken? Either way, next time you go camping on a hot summer night in Africa, don't forget to bring a chicken.
A version of this article was published in Discover Magazine.