A pathogen is any virus, bacteria, or parasite that causes a disease. A human can become infected with a pathogen through various avenues, such as coming into close contact with a sick person or drinking contaminated water. Another method through which a person can become infected with a pathogen is from an insect bite. Insects, such as mosquitos, ticks, flies, and fleas, can transmit many diseases.
Diseases that are transmitted through insect bites produce the following symptoms:
The symptoms listed above are not all-inclusive. Each insect-borne disease has additional symptoms that are unique to that disease. For example, a distinct symptom of yellow fever is jaundice. A distinct symptom of African trypanosomiasis, also known as “African sleeping sickness,” is a disturbed sleeping pattern.
For some diseases, the symptoms can take a while to appear. For example, symptoms of malaria can take anywhere from 6 to 30 days to manifest.
Numerous diseases are transmitted through insect bites. In these situations, the insects are considered vectors for the disease. The disease is not only caused by the insect, but also the pathogen that is carried by the insect.
Below is a list of several diseases that are transmitted through insect bites. Beside each disease is the pathogen that causes the disease along with the insect vector.
| Disease | Pathogen | Vector |
| Malaria | Plasmodium parasites | Mosquito |
| Yellow fever | Yellow fever virus | Mosquito |
| Zika | Zika virus | Mosquito |
| Dengue fever | Dengue virus | Mosquito |
| Chikungunya | Chikungunya virus | Mosquito |
| Lyme disease | Borrelia bacteria | Tick |
| West Nile virus | West Nile virus | Mosquito |
| Filariasis | Wuchereria bancrofti roundworms | Mosquito |
| Japanese encephalitis | Japanese encephalitis virus | Mosquito |
| Tick-borne meningoencephalitis | Meningoencephalitis virus | Tick |
| Tick-borne spotted fever | Rickettsia bacteria | Tick |
| African trypanosomiasis | Trypanosoma brucei parasite | Tsetse fly |
| Rickettsia felis | Rickettsia felis bacterium | Flea |
| African tick-bite fever | Rickettsia africae bacterium | Tick |
| Crimean-Congo haemorrhagic fever | Crimean-Congo haemorrhagic fever virus | Tick |
The risk factors for insect-borne diseases are listed below:
The likelihood of developing an insect-borne disease increases if one travels to or lives in areas where these diseases are common. For example, one region that malaria is endemic to is the tropical regions of sub-Saharan Africa. The odds of contracting malaria increase when one travels to or lives in this area.
Most insect-borne diseases are seasonal. For example, the transmission rate of malaria increases from May to July due to the season’s rainfall, heat, and humidity.
Children under 5 years old are more likely to suffer from insect-borne diseases since their immune system is less developed. Older adults are more likely to suffer from insect-borne diseases since their immune system is weakened.
The diagnosis for an insect-borne disease consists of the following:
Insect-borne diseases caused by bacteria are typically treated with a one-week regimen of antibiotics. Some diseases, such as Lyme disease, may require longer regimens. The antibiotic of choice is doxycycline.
Insect-borne diseases caused by parasites are treated with medication as well. However, there is no broad-spectrum drug that can kill all parasites. Each parasite requires its own unique drug. For example, numerous antimalarial drugs exist to kill the Plasmodium parasites that cause malaria. Meanwhile, anti-Trypanosoma drugs are needed to kill the parasites that cause African trypanosomiasis.
Insect-borne diseases caused by viruses have no specific treatment regimen. For most viral diseases, while waiting for the body’s immune system to fight off the virus, treatment consists of easing the symptoms of the disease. One exception is Crimean-Congo haemorrhagic fever (CCHF), which has been treated by the antiviral drug ribavirin. However, there is debate on whether ribavirin is truly successful or not in treating CCHF.
The best method for preventing insect-borne diseases is to prevent insect bites. This can be achieved by following the recommendations listed below:
It should be noted that there are various drugs and vaccines available to prevent several insect-borne diseases. For example, there are drugs that can be taken to prevent malaria. Vaccines are available to prevent yellow fever, Japanese encephalitis, and tick-borne meningoencephalitis. Consult a doctor on whether any of these medicines are necessary before travelling abroad.