[1]
Move over, MERS [2] – there’s a new virus in town.
The virus is called chikungunya, a name derived from an African word that loosely translates as “contorted with pain.” People who have had the virus or witnessed it firsthand say the name is fitting:
“It is terrible, I have never in my life gotten such an illness,” said [3] Maria Norde, a 66-year-old woman from the Caribbean island of Dominica. “All my joints are in pain.”
“My 22-year-old son is brave, but now he’s crying like a kid. His arms, his neck, his back, every part of his body is in pain,” said [4] Marco Dorival in Port-au-Prince.
Symptoms usually appear 3-7 days after infection, and the first two are typically the abrupt onset of a fever and joint pain. Other symptoms [5] including headache, tiredness, nausea, vomiting, rash, and muscle aches may follow.
Chikungunya is transmitted to humans primarily by two species of mosquito: the tropical Aedes aegypti and Aedes albopictus (the Asian tiger mosquito). Both species have taken up residence in the US. A few cases of the virus have been reported in Florida recently.
An RNA virus that belongs to the alphavirus genus of the family Togaviridae, chikungunya is similar to dengue [6] in some ways – both are viral infections spread by mosquitoes, and both are transmitted from human to human by the bites of infected female mosquitoes.
A mosquito carrying either virus can infect more than a dozen people in its lifetime.
The method of transmission is rather fascinating, as explained by Carrie Arnold for PBS [7]:
A person who is infected with chikungunya can carry the virus in their bloodstream for up to a week. This means that they can spread the virus to any Ae. aegypti mosquito that bites them during this time.
Once the mosquito drinks the blood containing chikungunya, the virus replicates in the mosquito’s gut. From there, it rapidly spreads to the salivary glands where it remains for the rest of the mosquito’s life. When the mosquito bites another human for its next meal, it injects a small amount of saliva into the bite to keep the blood from clotting. For mosquitoes infected with chikungunya, this dollop of virus-infused spit enters the bloodstream of the waiting human. Once it is back in a human, the virus begins its cycle of replication all over again. After two to seven days, the newly infected person has high levels of virus in the bloodstream, and the cycle can restart.
Chikungunya is usually less deadly than dengue. Fatalities linked to the virus are rare and typically occur in older people who have other serious health problems.
An estimated 60-90 percent of people who contract chikungunya develop symptoms, compared with only 20 percent of those with dengue. Blood tests can confirm the presence of the virus.
Chikungunya rarely kills and most people recover completely, but sufferers are often unable to sit up for weeks. Those infected are sometimes debilitated and unable to work for several months.
Treatment focuses on remedies for pain, lots of rest, and ensuring adequate fluid intake to prevent dehydration.
As with most transmittable diseases, an ounce of prevention is worth a pound of cure. Knowing how to avoid mosquito bites and what to do if you are bitten can help you avoid this unpleasant virus and others associated with the blood-sucking pests.
Both of the mosquito species that spread chikungunya can be found biting during the day, but experts say [5] there may be peaks of activity in the early morning and late afternoon. Both are also found biting outdoors, but Ae. aegypti will also readily feed indoors. Recommendations to avoid bites by staying indoors from dusk until dawn may not help much with these species.
One way to reduce the risk of mosquitoes shacking up in your home or yard is to eliminate any standing water around your property. Mosquitoes lay eggs in standing water, so empty birdbaths, buckets, kiddie pools, and any other water receptacles you have sitting around.
Check window screens for holes – the critters can and will get through them.
Mosquitoes are attracted to extra body heat and carbon dioxide [8] – the more you emit, the more likely you are to become a mosquito magnet. Outdoor exercise increases body heat, lactic acid, and expelled carbon dioxide – making you all the more appealing to bite. Pregnant women are also at higher risk of being bitten for the same reasons.
Summer barbeques often include the consumption of alcohol, but unfortunately, mosquitoes appear to love beer too, according to a small study [9] conducted in 2002.
Health officials usually recommend products containing the powerful chemical DEET to repel mosquitoes, but that recommendation is not without controversy – some researchers [10] believe the substance may be a neurotoxin. In addition, research published in the science journal Plos One [11] has shown that the Aedes aegypti species of mosquito is resistant to DEET [12]. The insect, which is responsible for spreading both dengue and yellow fever ignores the chemical as soon as its second exposure.
If you decide to use repellants containing DEET, be sure to follow the safety precautions on the label. A study published in The New England Journal of Medicine [13] says that DEET is still the “gold standard” for protection against mosquito bites, with a “40-year history of safety and almost 8 billion applications.” Less than 50 cases of serious toxic effects have been documented since 1960, and most of those resolved without permanent injury or disease. The findings of that study say most of the cases of toxic effects “involved long-term, heavy, frequent, or whole-body application of DEET. No correlation has been found between the concentration of DEET used and the risk of toxic effects.”
Alternatives to DEET do exist. One of them, oil of lemon eucalyptus, is said to be one of the most effective natural mosquito repellents on the market and is recommended by the Centers of Disease Control [14]. The active ingredient in oil of lemon eucalyptus is cineole, which has several antiseptic and insect repellent properties when applied to the skin. Oil of lemon eucalyptus also provides comparable protection to low concentrations of DEET. Lavender oil has also shown to have mosquito-repelling power.
Soybean oil also has powerful mosquito-repelling powers. Soybean-oil-based repellents protected against mosquito bites for an average of 1.5 hours [13].
Several studies [15] have shown that catnip oil repels mosquitoes – in fact, one study found that it is 10 times more effective than DEET [16].
Whatever type of repellant you decide to use, apply it AFTER you smear on sunscreen (if you use it).
Burning candles also can help keep mosquitoes away. Citronella isn’t what repels the critters – the smoke is what they don’t like. Candles of any scent or backyard torches should work just as well.
Using fans can help too – mosquitoes aren’t strong fliers, and fans can keep them from landing on you.
What about those annoying bug zapper machines? An entomology professor from the University of Delaware published a study in 1996 that showed that out of nearly 14,000 insects killed by six zappers in one summer, only 31 were biting fliers [17]. Another 2,000 were beneficial bugs that keep real pests at bay, and the others were harmless species. Mosquitoes prefer dim light, and are repelled by the bright light of the zappers anyway.
According to the Mayo Clinic, taking a daily dose of 75 to 150 milligrams of vitamin B-1 [18] (thiamin) could slightly change your scent in a way that might keep mosquitoes away, but the research isn’t conclusive. Eating garlic is sometimes recommended as a mosquito repellant, but experts say it is more likely to repel PEOPLE than pests.
Another way to control mosquitoes in your yard is to build bat houses [19]. Despite their association with spooky stories and haunted houses, bats are actually friendly and beneficial to have around – they love to eat mosquitoes and are an essential part of our ecosystem. Some bats can catch up to 600 mosquitoes an hour. In Austin, Texas there is a bat colony [20], estimated to have up to 1.5 million bats during peak season, that has been estimated to eat almost 10,000-30,000 pounds of insects.
Of course, the standard recommendation to wear light-colored clothing, long-sleeves, and long pants work too. The less skin you have exposed, the less opportunity a blood-sucker has to make you its next victim.