Mosquitos are known to cause more human suffering than any other organism in the world. According to the American Mosquito Control Association, a scientific/educational, not-for-profit public service association founded in 1935, more than one million people die worldwide from mosquito borne diseases every year. Mosquito-borne diseases are those diseases which are transmitted to humans through the bite of infected mosquitos. They not only carry diseases which affect humans but are quite capable of transmitting several diseases and parasites to dogs and horses as well. There is quite a long list of the common illnesses which one gets from mosquito bites. Here is a closer look at each of them.
What are mosquito-borne diseases?
The mosquito, which is Spanish for ‘small fly’, is an insect which belongs to the Culicidae family. There are thousands of mosquito species and the diseases carried and transmitted by such organisms are known as mosquito-borne diseases. The diseases spread by these organisms can be originally due to a parasite, as in the case of malaria, or by viruses, as in the case of Zika fever. Multiple factors like urbanization, global travel and growth in human population have increased the risk of mosquito-borne diseases. The most common types of mosquito-borne diseases are:
Symptoms Specific to Mosquito-borne Diseases
The symptoms of mosquito-borne diseases may be specific to the kind of disease involved. These are:
- Dengue: Symptoms include rash, fever, headache, bleeding from the nose or gums, and easy bruising.
- Malaria: Symptoms are fever, chills, vomiting and headache.
- Chikungunya: Symptoms include rashes, headache, severe joint pain, nausea and fatigue.
- Yellow fever: In this disease, skin and eyes look yellow-ish, high fever accompanied by headache, chills, vomiting and backache.
- Zika virus: Symptoms are mild and include fever, joint and muscle pain, rash or pinkeye. However, it is more severe in pregnant women as it can cause birth defects like small heads and brain damage in the babies.
- Encephalitis: If you get this disease, you will experience fever, nausea, headache and inflammation around the brain and spinal cord.
The majority of infections are asymptomatic, showing no external signs of infection while contributing to the transmission of the parasite. These asymptomatic infections still cause damage to the lymphatic system and the kidneys and alter the body’s immune system. When lymphatic filariasis develops into chronic conditions it leads to lymphoedema (tissue swelling) or elephantiasis (skin/tissue thickening) of limbs and hydrocele (scrotal swelling). Involvement of breasts and genital organs is common
Causes Specific to Mosquito-borne Diseases
The vectors of different mosquito-borne diseases depend upon the disease and the parasites or viruses causing it:
- Dengue: This is a serious, arboviral disease found mainly in America, Asia and Africa. The vectors of dengue are Aedes aegypti and Aedes albopictus.
- Malaria: This is an ancient disease originating from Africa. The malaria parasite is known as plasmodium and transmitted via the female Anopheles mosquitos.
- Chikungunya: This disease is caused due to the chikungunya virus which is a pathogen transmitted via Aedes mosquitos. Although, it is not likely fatal, the symptoms are persistent and stay on for several weeks.
- Yellow fever: Yellow fever is present only in the tropical areas of Africa and America. The virus, flavivirus, is generally transmitted via Aedes aegypti mosquitos.
- Zika virus: This virus is the most recent of mosquito-borne diseases emerged. The virus is classified as a Flavivirus and transmitted primarily via the Aedes aegypti mosquito.
- Encephalitis: This is one of the most serious mosquito-borne diseases caused by an arbovirus which severely affects the central nervous system. The carriers include mosquitos of the Culex species.
- Filariasis : Lymphatic filariasis, commonly known as elephantiasis, is a tropical disease. Infection occurs when filarial parasites are transmitted to humans through mosquitoes. Infection is usually acquired in childhood causing hidden damage to the lymphatic system. Lymphatic filariasis is transmitted by different types of mosquitoes for example by the Culex mosquito, widespread across urban and semi-urban areas, Anopheles, mainly found in rural areas, and Aedes, mainly in endemic islands in the Pacific.
Treatment depends upon the type of mosquito-borne disease involved. The general treatment techniques include:
- Dengue: Getting enough rest and treating the symptoms with fluids and pain relievers are the only things you can do in case of dengue. Sometimes it can lead to hemorrhagic fever, in which the small blood vessels leak and fill up fluid in the belly and lungs. In such cases, medical care is needed right away.
- Malaria: Treatment consists of medications like antimalarials and antibiotics. People also take antimalarial drugs before, after or during a trip to places where malaria is common.
- Chikungunya: There is no absolute cure, but most people recover from this condition. Rest, fluids and pain relievers, non-steroidal anti-inflammatory drugs and analgesics are used for treatment.
- Yellow fever: There is no specific treatment for this disease. Efforts are aimed at managing symptoms and preventing complications. Oral rehydration therapy is one such way.
- Zika virus: Treatment is targeted at relieving the symptoms with rest, fluids and medications like acetaminophen. There is no vaccine to prevent this disease currently.
- Encephalitis: This can be self-healing or the underlying cause may be addressed. The treatment includes antiviral drugs and anticonvulsants, bed rest, fluid intake and symptomatic relief.
- Filariasis : The main goal of treatment of an infected person is to kill the adult worm. Diethylcarbamazine citrate (DEC), which is both microfilaricidal and active against the adult worm, is the drug of choice for lymphatic filariasis. Ivermectin is effective against the microfilariae, but has no effect on the adult parasite.
There are a number of things which you can do to protect yourself from being bitten by mosquitos. These are:
- Wearing long sleeved shirts and long pants, preferably in light colors.
- Try to avoid being outdoors for long between dawn and dusk.
- Apply an insect repellant containing permethrin on your clothes and mosquito nets.
- On your skin, you should use insect repellants containing DEET or picaridin.
- Try to set up insect screens over the windows and mosquito netting over the beds.
- Mosquito coils can be burned every once in a while, or you could use plug-in mosquito zappers.
- Sleeping in air-conditioned rooms keeps out mosquitos.
- Identify all such places around your house where rainwater gets collected. Remove empty containers and pot plant trays.
- Make sure to clean all rainwater and septic tanks.
- Keep the gutters clean and flush any unused toilets at least once every week.
- Also, if you are traveling to mosquito-prone areas, you could get vaccinations, like for yellow fever, encephalitis etc. Antimalarial drugs also help.
This is all that you need to know about the different mosquito-borne diseases plaguing the world today. Make sure to follow appropriate preventive measures, stay alert and avoid getting bitten by mosquitos, especially in infection-prone areas. Talk to your doctor before travelling to such areas and take the necessary drugs or vaccinations for maximum effect.