There are lots of types of mosquitoes in the world. They are very irritating to humans especially during high mosquito seasons. It is well-known that only mosquito females are blood-eating insects. They have a special tube-like proboscis to pierce the skin and suck host’s blood. Females need this high-quality protein meal for oviposition. Of course, the amount of taken blood is insignificant for hosts. However, the saliva that was injected into skin and left in the place of bite can be highly allergic and irritating. It is likely to result in a dermal irritation as allergic reaction to mosquito bites. It causes inflammatory process and intense itching in mosquito bite swelling. Treatment of mosquito bite allergy takes time and money . However, there are ready-to-use products and homemade remedies to stop mosquito bites from itching. In fact, allergic reaction is the lesser evil to compare with infecting by mosquito borne diseases.
The Mosquitoes are Vectors of Saliva-borne Diseases
It is known that only some mosquito species are vectors of diseases, which are hazardous, even lethal, to humans. It means that these blood-sucking pests are carriers of parasites and viruses from one host-organism to others.
Note that there are similar-looking midge insects (Chironomidae, Tipulidae) and other mosquito species that are not blood-feeding. It is obvious that these insects do not transmit mosquito borne diseases.
Transmission Mechanism of mosquito borne sickness
Furthermore, even among disease-carrying mosquitoes, neither all species of mosquitoes, nor all strains of a given genera or subfamily spread the same illnesses, nor do they all transmit the virus under the same circumstances. It is interesting to mention that blood-eating species of mosquitoes are very selective and specialise in particular hosts in supportive environment.
However, when biting insects experience starvation and severe competition for food, they can change their preferences. Imagine that a mosquito female of Culiseta melanura feed selectively on passerine birds, when the conditions become hard, they begin attacking mammals more readily and are likely to suck the blood of animals and humans as their new hosts. This species of birds is the main reservoir of the Eastern equine encephalitis virus in North America. Soon, the blood-eating insects are likely to cause epidemics of mosquito borne diseases in humans and horses. 1
Mosquito Borne Diseases
Mosquito is a mechanical bridge for disease-causing organisms between two vertebrate species. Blood-eating insects are responsible for the transmission of viruses and parasites. Mosquito born illnesses are west Nile virus, Chikungunya, yellow fever, malaria, dengue fever, Zika virus, filariasis and others. The table below is devoted to the important associations of disease-causing and virus-carrying organisms transmitted to humans and animals by blood-feeding mosquitoes.
The table contains information about viruses that are transmitted by some species of mosquitoes| Geographical distribution | Mosquito borne virus | Major virus vectors | Major hosts |
|---|---|---|---|
| Africa | -Semliki forest virus (South and North Africa, Madagascar) -chikungunya -Wesselsbron -West Nile virus -Sandfly fever -African horse sickness | -mosquitoes -mosquitoes -mosquitoes -Culex spp. - Phlebotomus papatasii -Culicoides spp. | -humans -humans and monkeys -humans, sheep -humans, birds -humans -equines |
| North America | -Venezuelan equine encephalitis (Southern USA) -Western equine encephalitis -California encephalitis | -mosquitoes -Culex spp. -Aedes spp., Culex spp. | -humans, rodents, equins, birds -humans, rodents, equins, birds, amphibians -humans |
| America | -Dengue (Caribbean) -St Louis encephalitis -Myxomatosis | -Aedes spp., Aedes aegypti - Culex tarsalis, Culex spp. -mosquitoes, Culicoides spp | -humans -humans, rodents, bats, birds -rabbits |
| South America | -Semliki forest virus (Amazon) -Venezuelan equine encephalitis -Western equine encephalitis | -mosquitoes -mosquitoes -Culex tarsalis | -humans -humans, rodents, equins, birds, -humans, rodents, equins, birds, amphibians |
| Tropical America | -Yellow fever | -Aedes aegypti | -humans, monkeys |
| Europe | -Venezuelan equine encephalitis -Western equine encephalitis (Italy, Czech Republic) -West Nile virus (Mediterranean) -Myxomatosis | -mosquitoes -Culex spp -Culex tarsalis -mosquitoes, Culicoides spp | -humans, rodents, equins, birds -humans, rodents, equins, birds, amphibians -humans and birds -rabbits |
| Asia | -chikungunya (India, Eastern Asia) -Venezuelan equine encephalitis (India) -Dengue (South-Eastern Asia) -Japanese encephalitis -West Nile virus (India, Near East, former Republics of USSR) | -mosquitoes -mosquitoes -Aedes spp., Aedes aegypti - Culex tritaeniorrhynchus, Culex spp. -Culex spp. | -humans and monkeys -humans, rodents, equins, birds -humans -humans, equines, birds, pigs -humans and birds |
| Australia | -Murray valley encephalitis (plus in Philippines and New Guinea) -Myxomatosis | -Culex annulirostris -mosquitoes, Culicoides spp | -humans, birds -rabbits |
| Worldwide | -Bluetongue | -Culicoides spp. | -rodents, sheep |
Various mosquito species are estimated to spread viruses and parasites to more than 700 million people each year in South America, North America, Mexico, Africa, Europe, Australia and Asia, with about two millions of resultant deaths annually. Still the mortality rates are many times higher.
Malaria
Human malaria is a term collectively refered to parasitic diseases, caused by various species of Plasmodium, carried by female malaria mosquitoes of the genus Anopheles. There are about 430 species of Anopheles on the Earth. However, over 100 of them are able to inject malaria virus and transmit this disease to humans. In nature, only 30-40 commonly do so.
Malaria causes typical symptoms of febril affection that include vomiting and nausea, fever, fatigue, and headaches. Severe malaria causes yellow skin, seizures, coma, or death. Symptoms usually begin in 10-15 days after being bitten by malaria-causing mosquitoes.
Chikungunya
Chikungunya is one of rare mosquito-borne diseases. Though, it is widespread throughout Africa, Eastern Asia, especially in India. In the USA it is not so frequent, with cases mostly found in Texas and southern Florida.
Deseased often experience mild symptoms. They suffer from headaches and vomiting, joint pain, rash and fever.
Dengue fever
Tourists often return from the Caribbean, Central and South America, South Central Asia with signs of fever. The most common cause of this fever is ingress of dengue virus, which is spread via the bites of infected mosquitoes of Aedes aegypti.
Common symptoms of mosquito dengue are high fever, vomiting, nausea, severe headaches, rash, pain in muscles and eyes, joint.
This dengue mosquito borne illness can be well treated, though still fewer than 1% of diseased die from severe dengue. Fortunatelly, this virus cannot be transmitted from person to person.
West Nile virus
West Nile virus is spread by several mosquito species of Culex spp. This virus among other mosquito borne diseases is a matter of concern in Central and North Africa, Mediterranean countries, India and in countries of the former Soviet Union. It is also a current affair of the U.S, as instances of West Nile virus have spread throughout the country. Infected people often experience mild symptoms. They suffer from fever, body aches, headache, and a mild rash.
Zika virus in Brazil
Zika virus is a member of the Flaviviridae family and is transmitted to humans by mosquitoes of Aedes aegypti and forest mosquitoes of Ae. africanus, Ae. hensilli, Ae. luteocephalus, Ae. furcifer. It is related to other mosquito borne diseases, such as Dengue, Japanese encephalities and West Nile fever. Zika mosquito virus 2016, which caused outbreaks in Brazil, was first found in Africa and South Eastern Asia. Since 2015 this virus is activelly spread in South and Central America.
The displayed symptoms resemble mild form of mosquito dengue. Infected people suffer from fever, rash, fatugue or lassitude, headaches and joint pain.
Moreover, the Zika is currently considered as a harmful mosquito virus for babies. It is able to cross the placenta and affect the fetus, which results in cases of microcephaly and other causes of adverse outcomes during pregnancy. In addition, the Zika virus is responsible for Guillain-Barré syndrome (GBS) in adults as well. How to prevent ZIKV bites read here.
Eastern equine encephalitis virus
Eastern equine encephalitis virus is also known as Triple E or sleeping sickness. It is a mosquito borne disease widely-spread in North, Central and South America and the Caribbean. Moreover, this virus was first met in Massachusetts, USA in 1831. During that outbreak, viral encephalitis killed 75 horses.
Displayed symptoms in humans include headaches with altered mental status, photophobia, seizures and meningeal irritation; severe fever and pain in muscles. In fact, the signs of infection occur in 3-10 days after the EEE infected mosquito bite.
Can mosquitoes transmit hiv?
Recently, the matter of Human immunodeficiency virus was a public health concern. Practical considerations and detailed studies of epidemiological patterns in research laboratories proved that any potential transmission of the HIV by various species of mosquitoes, ticks and other blood-sucking insects is unlikely, even impossible, at worst. 2
In addition, you can read our article about how to prevent saliva-born diseases caused by mosquito bites. Avoid mosquito crossing and be healthy!
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