Insect Disease Prevention - July 21, 2009 Newsletter

Insect Disease Prevention

EHE Newsletter, Volume 9, Number 15
July 21, 2009

There are many diseases that are spread by insects. Very few, however, are actually caused by the insects themselves. In most cases, a micro–organism is the pathogen (cause of the disease) and the insect that spreads the pathogen is known as the vector (carrier). Insects such as mosquitoes, fleas, flies and ticks are capable of spreading diseases that are caused by many different types of micro–organisms, including bacteria and viruses.

The vector–borne spreading of germs occurs when an insect that carries a germ on its body, or in its intestinal tract, lands on you or bites you. The germ(s) then moves into your body and can make you ill. Sometimes the germs that cause infectious disease need the insect for specific biological purposes such as using the insect’s body to multiply, which is necessary before the germs can infect a new host.

Examples of diseases spread by insect carriers include:

  • Mosquito: West Nile Virus, malaria, yellow fever, dengue, filarial
  • Ticks: Encephalitis, Lyme Disease, typhus
  • Black Fly: Onchocerciasis (river blindness)
  • Sandfly: Leishmaniasis
  • Tsetse Fly: Sleeping sickness

In North America, ticks are the leading cause of vector–borne infections. Globally, ticks are second only to mosquitoes as vectors of human disease.

Preventing the Spread of Disease

Some diseases such as malaria and yellow fever can be prevented by vaccinations or preventive medications. For many other diseases, however, the only available preventive measure is avoiding bites in the first place. The following simple precautions can significantly reduce, if not prevent, the risk of disease transmission by insects.

  • Take a close look at the windows in your home. Make sure that all screens are in good repair and fit properly, and that all windows without screens are closed. If any screens have rips or tears in them, replace them right away.
  • Take steps to rid your yard of all standing water. Standing water is a breeding ground for insects and mosquitoes. It can be found in wading pools, pots and planters around the yard, gutters that are backed up, and in toys or tools that are left in the yard.
  • Insect repellents help reduce exposure to mosquito bites and allow enjoyment of the outdoors with a lower risk of disease. A wide variety of insect repellent products are available. The Centers for Disease Control and Prevention (CDC) recommend the use of products containing active ingredients that have been registered with the U.S. Environmental Protection Agency (EPA) for use as repellents applied to skin and clothing. EPA–registered repellents include products containing DEET and picaridin. Most authorities recommend repellents containing DEET as the most reliable and long–lasting. In general, the more DEET that a repellent contains, the longer it can protect against mosquito bites. Low concentrations provide shorter–duration protection than higher concentrations. Concentrations of more than 50 percent DEET, however, do not appear to provide any added benefit. Picaridin, which is available at 7 and 15 percent concentrations, requires more frequent application.
  • Certain products that contain permethrin (a chemical that is also registered with the EPA) are recommended for use on clothing, shoes, bed nets, and camping gear. Permethrin–treated clothing repels and kills ticks, mosquitoes and other arthropods, and retains effectiveness after repeated laundering. It is not intended for use directly on the skin.
  • The risk of insect bites is greatest between dusk and dawn, but insects can bite at any time of the day. Protect yourself by keeping as much skin covered as possible; by wearing long–sleeved shirts, long pants, socks and closed shoes; by tucking your pant legs into your socks and your shirt into your pants; and by wearing a broad–rimmed hat to keep insects away from your face.
  • Wear white or light–colored clothing to detect ticks more easily, and inspect your body and clothing for ticks during outdoor activity and at the end of the day. Removing ticks quickly can prevent some infections.
  • Do not use scented soaps, perfumes or hair sprays as they may attract insects.
  • When travelling, stay in air–conditioned or well–screened housing and/or sleep under an insecticide–treated bed net. Bed nets should be tucked under mattresses and can be sprayed with a repellent if not already treated with an insecticide.

It is important to note that most insect bites will not cause a serious illness, but some can have serious consequences. Fortunately, you can enjoy time spent outdoors by following simple precautions that can significantly reduce your exposure to insects that can carry dangerous diseases.

MEDICAL DISCLAIMER: The information is not intended to constitute medical advice and is not a substitute for consultation with a physician or other health care provider. Individuals with specific complaints should seek immediate consultation from their personal physicians.