Diseases Caused and Carried by Insects Around the World

Michael Powell and Dr. Oliver Fischer describe a number of diseases in their book, 101 Illnesses you Don't Want to Get. A surprising number of these are caused by parasites or passed on through animals and insects. In many cases these sicknesses can be prevented by avoiding the source. This can be as simple as using insect repellent and mosquito nets or keeping away from infected areas.

Diseases Passed on by Mosquitoes

Mosquitoes are responsible for passing on a number of diseases. These include the following:

• Dengue fever is a viral illness that occurs in tropical and subtropical regions. It is characterized by a high fever and rash and may develop into the more serious dengue haemorrhagic fever. There is no vaccine and only symptomatic treatment is available
• Japanese encephalitis is a viral sickness that affects the central nervous system. It is confined to Asia and can be prevented by vaccination. Thirty percent of sufferers will die and there is no treatment available.
• Malaria is common worldwide and is responsible for one million deaths annually. 90% of cases occur in sub-Saharan Africa. Symptoms include cycles of chills and fever, and jaundice and anaemia can result. Malaria can be treated and cured.
• West Nile fever is found in Africa, West Asia and the Middle East. The disease is passed on by mosquitoes that have become infected by feeding on infected birds. Symptoms resemble a mild case of flu but can develop into meningitis or encephalitis.
• Yellow fever is passed on by mosquitoes in parts of South America and sub-Saharan Africa. A vaccination is available but there are vast areas where people have not been immunised. Symptoms are flu-like and only last for a few days but in 15% of cases, the disease will progress to the toxic phase. This is characterized by jaundice, abdominal pain, vomiting blood and possible kidney failure. Only symptomatic treatment is available.

Diseases Passed on by Other Insects

Various kinds of flies are also responsible for the spread of some nasty diseases:

• Tsetse flies in sub-Saharan Africa pass on sleeping sickness to humans. This disease affects the central nervous system and the chances of survival without treatment are nil.
• Leishmaniasis is spread by the bite of infected sand flies. It is mostly found in the tropics and subtropics and there are over two million new cases each year. There are various strains and symptoms include ulcerated skin sores and lesions in the nose, mouth and throat. In severe cases, internal organs are attacked and the condition is fatal in 95% of cases that are not treated.

What Spreads the Bubonic Plague

The bubonic plague is carried by fleas which commonly live on rats but can also be found on domestic animals. On average, 2000 new cases are reported annually with the majority of these being in Africa and Asia. Symptoms include feverish chills, headaches and tiredness, and lymph glands become swollen and tender. The plague is treatable with antibiotics but still has a death rate of up to15% treated, and 60% untreated.

Mosquitoes, tsetse flies, sand flies and fleas are responsible for passing on a number of unpleasant and often fatal diseases. Many of these are found mostly in the poorer areas of the world. Prevention is possible through immunisation, the use of insect repellent and nets, and treatment is available for certain conditions.

Reference:

101 Illnesses You Don't want to Get , by Michael Powell with Dr Oliver Fischer, Cassell Illustrated, 2005, ISBN 1-84403-389-9