Medical entomology

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Aedes albopictus
A U.S. Navy medical entomologist identifying insects US Navy 100506-N-7498L-189 Lt. Brian Heintschel studies a sample of insects collected from ships and shore facilities.jpg
A U.S. Navy medical entomologist identifying insects

The discipline of medical entomology, or public health entomology, and also veterinary entomology is focused upon insects and arthropods that impact human health. Veterinary entomology is included in this category, because many animal diseases can "jump species" and become a human health threat, for example, bovine encephalitis. Medical entomology also includes scientific research on the behavior, ecology, and epidemiology of arthropod disease vectors, and involves a tremendous outreach to the public, including local and state officials and other stake holders in the interest of public safety.

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Public health entomology has seen a huge surge in interest since 2005, due to the resurgence of the bed bug, Cimex lectularius.

Insects of medical importance

There are many insects (and other arthropods) that affect human health. These arthropods include Diptera, Hemiptera, Phthiraptera, and Siphonaptera. They can parasitize, bite, sting, cause allergic reactions, and/or vector disease to humans. It can be impossible to know the full impact that insects and other arthropods have on human health. Medical entomologists worldwide are working to combat the known effects in order to improve public health.

Personal pests

Personal pests such as lice, fleas, bedbugs, ticks, scabies mites, may vector pathogens. They are hematophagous, meaning they feed on the blood of their host. Nearly all personal pests can be transmitted to an uninfected host with prolonged exposure to an infected host. Lice, fleas, bedbugs, and ticks are known as ectoparasites. Ectoparasites live on the skin of their host. They have adaptations that allow them to access the nutrients inside of the host, such as methods to penetrate skin, insert digestive enzymes and a gut microbiome that can digest the nutrients received from the host. [1] While these ectoparasites feed, the transfer of fluids may transmit diseases such as typhus, plague, and Lyme disease. It is also suspected that bedbugs may also be vectors of hepatitis B. [2]

Scabies mites cannot be classified as ectoparasites. The mite that causes scabies, Sarcoptes scabiei also known as the itch mite, burrows into the skin of its host making it an endoparasite. [3] The act of S. scabiei living in the skin and the allergic response to the parasite is the condition known as scabies.

Housefly

The housefly is a very common and cosmopolitan species which transmits diseases to man. The organisms of both amoebic and bacillary dysenteries are picked up by flies from the faeces of infected people and transferred to clean food either on the fly's hairs or by the fly vomiting during feeding. Typhoid germs may be deposited on food with the fly's faeces. The house fly cause the spread of yaws germs by carrying them from a yaws ulcer to an ordinary sore. Houseflies also transmit poliomyelitis by carrying the virus from infected faeces to food or drink. Cholera and hepatitis are sometimes fly-borne. Other diseases carried by houseflies are Salmonella, tuberculosis, anthrax, and some forms of ophthalmia. They carry over 100 pathogens and transmit some parasitic worms. The flies in poorer and lower-hygiene areas usually carry more pathogens. Some strains have become immune to most common insecticides.

Cockroach

Cockroaches carry disease-causing organisms (typically gastroenteritis) as they forage. Cockroach excrement and cast skins also contain a number of allergens causing responses such as, watery eyes, rashes, congestion of nasal passages and asthma.

Biting insects

There are many insects that bite including mosquitoes, biting midges, sandflies, black flies, Horse-flies, and stable flies. Through feeding, insects or other arthropod vectors can transmit diseases to humans. Medical entomologists and other medical professionals have helped to develop vaccines that can prevent humans from contracting some of those diseases. They have also developed ways to prevent the arthropods from biting humans. According to a study by the Centers for Disease Control and Prevention published in May 2018, illnesses caused by insect bites have tripled from 2004 to 2016. [4]

Insect-borne diseases

Major

Minor

See also

Related Research Articles

<span class="mw-page-title-main">Mosquito</span> Family of flies

Mosquitoes, the Culicidae, are a family of small flies consisting of 3,600 species. The word mosquito is Spanish and Portuguese for little fly. Mosquitoes have a slender segmented body, one pair of wings, three pairs of long hair-like legs, and specialized, highly elongated, piercing-sucking mouthparts. All mosquitoes drink nectar from flowers; females of some species have in addition adapted to drink blood. The group diversified during the Cretaceous period. Evolutionary biologists view mosquitoes as micropredators, small animals that parasitise larger ones by drinking their blood without immediately killing them. Medical parasitologists view mosquitoes instead as vectors of disease, carrying protozoan parasites or bacterial or viral pathogens from one host to another.

<span class="mw-page-title-main">Arbovirus</span> Class of viruses which are transmitted by arthropods

Arbovirus is an informal name for any virus that is transmitted by arthropod vectors. The term arbovirus is a portmanteau word. Tibovirus is sometimes used to more specifically describe viruses transmitted by ticks, a superorder within the arthropods. Arboviruses can affect both animals and plants. In humans, symptoms of arbovirus infection generally occur 3–15 days after exposure to the virus and last three or four days. The most common clinical features of infection are fever, headache, and malaise, but encephalitis and viral hemorrhagic fever may also occur.

<i>Aedes aegypti</i> Species of mosquito

Aedes aegypti, the yellow fever mosquito, is a mosquito that can spread dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents. The mosquito can be recognized by black and white markings on its legs and a marking in the form of a lyre on the upper surface of its thorax. This mosquito originated in Africa, but is now found in tropical, subtropical and temperate regions throughout the world.

<i>Culex</i> Genus of mosquitoes

Culex or typical mosquitoes are a genus of mosquitoes, several species of which serve as vectors of one or more important diseases of birds, humans, and other animals. The diseases they vector include arbovirus infections such as West Nile virus, Japanese encephalitis, or St. Louis encephalitis, but also filariasis and avian malaria. They occur worldwide except for the extreme northern parts of the temperate zone, and are the most common form of mosquito encountered in some major U.S. cities, such as Los Angeles.

Andrew Spielman was a prominent American public health entomologist and Professor of Tropical Public Health in the Department of Immunology and Infectious Disease at the Harvard School of Public Health (HSPH).

<span class="mw-page-title-main">Disease vector</span> Agent that carries and transmits an infectious pathogen into another living organism

In epidemiology, a disease vector is any living agent that carries and transmits an infectious pathogen such as a parasite or microbe, to another living organism. Agents regarded as vectors are mostly blood-sucking insects such as mosquitoes. The first major discovery of a disease vector came from Ronald Ross in 1897, who discovered the malaria pathogen when he dissected the stomach tissue of a mosquito.

<i>Aedes vexans</i> Species of fly

Aedes vexans, the inland floodwater mosquito or tomguito, is a cosmopolitan and common pest mosquito.

<span class="mw-page-title-main">Mosquito-borne disease</span> Diseases caused by bacteria, viruses or parasites transmitted by mosquitoes

Mosquito-borne diseases or mosquito-borne illnesses are diseases caused by bacteria, viruses or parasites transmitted by mosquitoes. Nearly 700 million people contract mosquito-borne illnesses each year, resulting in more than a million deaths.

VectorBase is one of the five Bioinformatics Resource Centers (BRC) funded by the National Institute of Allergy and Infectious Diseases (NIAID), a component of the National Institutes of Health (NIH), which is an agency of the United States Department of Health and Human Services. VectorBase is focused on invertebrate vectors of human pathogens working with the sequencing centers and the research community to curate vector genomes.

<span class="mw-page-title-main">Kunjin virus</span> Subtype of West Nile virus

Kunjin virus (KUNV) is a zoonotic virus of the family Flaviviridae and the genus Flavivirus. It is a subtype of West Nile virus endemic to Oceania.

Rocio viral encephalitis is an epidemic flaviviral disease of humans first observed in São Paulo State, Brazil, in 1975. Low-level enzootic transmission is likely continuing in the epidemic zone, and with increased deforestation and population expansion, additional epidemics caused by Rocio virus are highly probable. If migratory species of birds are, or become involved in, the virus transmission cycle, the competency of a wide variety of mosquito species for transmitting Rocio virus experimentally suggest that the virus may become more widely distributed. The encephalitis outbreak in the western hemisphere caused by West Nile virus, a related flavivirus, highlights the potential for arboviruses to cause severe problems far from their source enzootic foci.

<span class="mw-page-title-main">Arthropod bites and stings</span> Medical condition

Many species of arthropods can bite or sting human beings. These bites and stings generally occur as a defense mechanism or during normal arthropod feeding. While most cases cause self-limited irritation, medically relevant complications include envenomation, allergic reactions, and transmission of vector-borne diseases.

Rickettsia felis is a species of bacterium, the pathogen that causes cat-flea typhus in humans, also known as flea-borne spotted fever. Rickettsia felis also is regarded as the causative organism of many cases of illnesses generally classed as fevers of unknown origin in humans in Africa.

<span class="mw-page-title-main">Ethyl butylacetylaminopropionate</span> Chemical compound

Ethyl butylacetylaminopropionate is an insect repellent whose trade name is IR3535 and was developed and commercialized by Merck KGaA (Germany). It is a colorless and odorless oil with a good skin feel in final products, and it is biodegradable.

<span class="mw-page-title-main">Hematophagy</span> Ecological niche involving feeding on blood

Hematophagy is the practice by certain animals of feeding on blood. Since blood is a fluid tissue rich in nutritious proteins and lipids that can be taken without great effort, hematophagy is a preferred form of feeding for many small animals, such as worms and arthropods. Some intestinal nematodes, such as Ancylostomatids, feed on blood extracted from the capillaries of the gut, and about 75 percent of all species of leeches are hematophagous. The spider Evarcha culicivora feeds indirectly on vertebrate blood by specializing on blood-filled female mosquitoes as their preferred prey. Some fish, such as lampreys and candirus; mammals, especially vampire bats; and birds, including the vampire finch, Hood mockingbird, Tristan thrush, and oxpeckers, also practise hematophagy.

Pylore Krishnaier Rajagopalan was an Indian vector control scientist, biologist and acarologist, known for his pioneering contributions to the control programmes against vector-borne diseases in India. He was a former director of the Indian Council of Medical Research managed Vector Control Research Centre, Pondicherry. He graduated in 1949 from the Banaras Hindu University and obtained a Masters in Zoology with University First Rank there itself in 1951. In 1952 he joined the fledgling Virus Research Centre in Pune, and worked under the supervision of some of the finest vector control specialists such as Dr T Ramachandra Rao. In recognition of his outstanding work as a young research scientist, in 1957 he was awarded a Fellowship by the Rockefeller Foundation to pursue a Master's program in Public Health from the University of California. He went on to secure a Diploma in Acarology from the University of Maryland at College Park.

Spondweni virus is an arbovirus, or arthropod-borne virus, which is a member of the family Flaviviridae and the genus Flavivirus. It is part of the Spondweni serogroup which consists of the Sponweni virus and the Zika virus (ZIKV). The Spondweni virus was first isolated in Nigeria in 1952, and ever since, SPONV transmission and activity have been reported throughout Africa. Its primary vector of transmission is the sylvatic mosquito Aedes circumluteolus, though it has been isolated from several different types of mosquito. Transmission of the virus into humans can lead to a viral infection known as Spondweni fever, with symptoms that include headache, nausea, myalgia and arthralgia. However, as SPONV is phylogenetically close to the ZIKV, it is commonly misdiagnosed as ZIKV along with other viral illnesses.

<span class="mw-page-title-main">Palm Creek virus</span> Species of virus

Palm Creek virus (PCV) is an insect virus belonging to the genus Flavivirus, of the family Flaviviridae. It was discovered in 2013 from the mosquito Coquillettidia xanthogaster. The female mosquitoes were originally collected in 2010 from Darwin, Katherine, Alice Springs, Alyangula, Groote Eylandt, Jabiru and the McArthur River Mine, and had since been preserved. The discovery was made by biologists at the University of Queensland. The virus is named after Palm Creek, near Darwin, from where it was originally isolated.

<i>Culex gelidus</i> Species of mosquito

Culex (Culex) gelidus is a species of mosquito belonging to the genus Culex. It is found in India, Sri Lanka, Bangladesh, Cambodia, China, Hong Kong, India, Indonesia, Japan, Laos, Malaysia, Myanmar, Nepal, New Guinea (Island); Papua New Guinea, Pakistan, Philippines, Taiwan, Thailand, Vietnam. In 1976, it was identified as a major vector of Japanese encephalitis virus, in India. From an experiment, it was evident that aqueous solution of Calotropis gigantea leaves possess larvicidal activity, mosquito repellent activity and ovicidal activity against Culex gelidus.

<span class="mw-page-title-main">Parasitic flies of domestic animals</span> Overview of parasite-transmitting flies

Many species of flies of the two-winged type, Order Diptera, such as mosquitoes, horse-flies, blow-flies and warble-flies, cause direct parasitic disease to domestic animals, and transmit organisms that cause diseases. These infestations and infections cause distress to companion animals, and in livestock industry the financial costs of these diseases are high. These problems occur wherever domestic animals are reared. This article provides an overview of parasitic flies from a veterinary perspective, with emphasis on the disease-causing relationships between these flies and their host animals. The article is organized following the taxonomic hierarchy of these flies in the phylum Arthropoda, order Insecta. Families and genera of dipteran flies are emphasized rather than many individual species. Disease caused by the feeding activity of the flies is described here under parasitic disease. Disease caused by small pathogenic organisms that pass from the flies to domestic animals is described here under transmitted organisms; prominent examples are provided from the many species.

References

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  2. Vector Control - Methods for Use by Individuals and Communities. World Health Organization. 1997. pp. 237–261.
  3. "Endoparasitic mites - Parasites - ALPF Medical Research". www.alpfmedical.info. Retrieved 2018-09-07.
  4. "Illnesses on the rise". Centers for Disease Control and Prevention. 2018-05-01. Retrieved 2018-09-07.