Warble fly

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Warble flies
The ox warble fly (Hypoderma bovis). Pen and ink drawing by Wellcome V0022585.jpg
Ox warble fly (Hypoderma bovis)
Ox Warble-fly.png
Life cycle
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Oestridae
Subfamily: Hypodermatinae
Genus: Hypoderma
Latreille, 1818
Species

Warble fly is a name given to the genus Hypoderma: large flies which are parasitic on cattle and deer. Other names include "heel flies", "bomb flies" and "gadflies", while their larvae are often called "cattle grubs" or "wolves." Common species of warble fly include Hypoderma bovis (the ox warble fly) and Hypoderma lineatum (the cattle warble fly) and Hypoderma tarandi (the reindeer warble fly). Larvae of Hypoderma species also have been reported in horses, sheep, goats and humans. [1] They have also been found on smaller mammals such as dogs, cats, squirrels, voles and rabbits.

Contents

Adult warble flies are large, hairy and bumblebee-like and brown, orange or yellow in color. The adults have vestigial mouthparts, so they cannot feed during their short lifespans, which can be as little as five days. [2]

They are found on all continents of the Northern Hemisphere, mainly between 25° and 60° latitude.

Infestations

The fly lays eggs on the forelegs of large animals. The eggs hatch within a week and penetrate the skin, where they migrate throughout the connective tissues (H. bovis) or to the esophagus (H. lineatum). After a few months, the larvae travel back to the skin surface and cause swellings called "warbles". They remain under the skin, and when destroyed by pressure, the larvae can cause large purulent swellings, or anaphylaxis. Upon emergence, the fly leaves holes in the skin. Large numbers of such punctures can render cattle hides valueless.

The migrating larvae can cause damage to meat, as the tunnels they make in the muscle fill with a substance known as "butcher's jelly". [2] Infestations also hinder weight gain and growth in the animals. Milk yields may also decline. Most infections in adult cows are minor, due to immunity developed over time.

Humans

In humans, the disease intracerebral myiasis is a rare infestation of the brain by the larva of H. bovis. It penetrates the brain by an unknown mode and causes symptoms such as convulsions and intracerebral hematoma. The first case of human warble fly infection in Britain (to a four-year-old boy on a farm near South Brent, Devon) was reported in the British Medical Journal in June 1924 by Dr Frederick William Style [3] Other cases appear in medical literature. [4] Myiasis of the human eye can be caused by H. tarandi, a parasite of reindeer. It is known to cause uveitis, glaucoma and retinal detachment. [5] H. lineatum and H. sinense may also infest humans. [5]

Treatment and prevention

Warble flies have been eradicated in many countries, beginning with Denmark and Western Germany, in the 1960s. It was eradicated in the United Kingdom in 1990. [6] [7] It is a notifiable disease. It may have been eradicated from Belgium.

From the 1980s, the preventive treatment is easier, by subcutaneous use of ivermectin, but the warble fly remains present in North Africa.

Warble fly larvae Hypoderma bovis larvae young.jpg
Warble fly larvae

See also

Related Research Articles

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Botfly Parasitic insect

Botflies, also known as warble flies, heel flies, and gadflies, are a family of flies technically known as the Oestridae. Their larvae are internal parasites of mammals, some species growing in the host's flesh and others within the gut. Dermatobia hominis is the only species of botfly known to parasitize humans routinely, though other species of flies cause myiasis in humans.

Myiasis Infestation of parasitic maggots

Myiasis is the parasitic infestation of the body of a live animal by fly larvae (maggots) which grow inside the host while feeding on its tissue. Although flies are most commonly attracted to open wounds and urine- or feces-soaked fur, some species can create an infestation even on unbroken skin and have been known to use moist soil and non-myiatic flies as vector agents for their parasitic larvae.

<i>Cochliomyia hominivorax</i> Species of fly

Cochliomyia hominivorax, the New World screw-worm fly, or screw-worm for short, is a species of parasitic fly that is well known for the way in which its larvae (maggots) eat the living tissue of warm-blooded animals. It is present in the New World tropics. There are five species of Cochliomyia but only one species of screw-worm fly in the genus is parasitic; there is also a single Old World species in a different genus. Infestation of a live vertebrate animal by a maggot is technically called myiasis. While the maggots of many fly species eat dead flesh, and may occasionally infest an old and putrid wound, screw-worm maggots are unusual because they attack healthy tissue.

<i>Dermatobia hominis</i> Species of fly

The human botfly, Dermatobia hominis, is a species of botfly whose larvae parasitise humans. It is also known as the torsalo or American warble fly, though the warble fly is in the genus Hypoderma and not Dermatobia, and is a parasite on cattle and deer instead of humans.

<i>Cordylobia anthropophaga</i> Species of fly

Cordylobia anthropophaga, the mango fly, tumbu fly, tumba fly, putzi fly, or skin maggot fly, is a species of blow-fly common in East and Central Africa. It is a parasite of large mammals during its larval stage. C. anthropophaga has been endemic in the subtropics of Africa for more than 135 years and is a common cause of myiasis in humans in the region.

<i>Cochliomyia</i> Genus of insects

Cochliomyia is a genus in the family Calliphoridae, known as blowflies, in the order Diptera. Cochliomyia is commonly referred to as the New World screwworm flies, as distinct from Old World screwworm flies. Four species are in this genus: C. macellaria, C. hominivorax, C. aldrichi, and C. minima. C. hominivorax is known as the primary screwworm because its larvae produce myiasis and feed on living tissue. This feeding causes deep, pocket-like lesions in the skin, which can be very damaging to the animal host. C. macellaria is known as the secondary screwworm because its larvae produce myiasis, but feed only on necrotic tissue. Both C. hominivorax and C. macellaria thrive in warm, tropical areas.

<i>Chrysomya bezziana</i> Species of fly

Chrysomya bezziana, also known as the Old World screwworm fly or screwworm, is an obligate parasite of mammals. Obligate parasitic flies require a host to complete their development. Named to honor the Italian entomologist Mario Bezzi, this fly is widely distributed in Asia, tropical Africa, India, and Papua New Guinea. The adult can be identified as metallic green or blue with a yellow face and the larvae are smooth, lacking any obvious body processes except on the last segment.

<i>Sarcophaga pernix</i> Species of fly

Sarcophaga pernix, also known as the red-tailed flesh fly, is a fly in the Sarcophagidae family. This fly often breeds in carrion and feces, making it a possible vector for disease. The larvae of this species can cause myiasis, as well as accidental myiasis. It is potentially useful in forensic entomology.

Hypodermyasis is a parasitic infection by the larvae of warble flies, most notably Hypoderma lineatum and Hypoderma bovis. These flies mostly infect cattle in the warmer areas of the northern hemisphere. Humans become hosts when they inadvertently swallow the eggs of those flies.

<i>Cephenemyia ulrichii</i> Species of fly

Cephenemyia ulrichii or the moose botfly, also called the elk botfly, moose nose botfly or moose throat botfly, is a large botfly that resembles a bumblebee. In the wild, they attack chiefly the nostrils and pharyngeal cavity of moose, but have been found in other deer species. There have also been several cases of C. ulrichii squirting their larvae into the eyes of human beings, a somewhat painful event that requires medical attention to forestall any possibility of serious damage.

<i>Oestrus ovis</i> Species of fly

Oestrus ovis, the sheep bot fly, is a widespread species of fly of the genus Oestrus. It is known for its parasitic predation and damage to sheep, deer, goats and sometimes cattle. There have also been many records of horse, dog and human infestation. In some areas of the world it is a significant pest which affects the agricultural economy.

Mites of livestock

Mites are small crawling animals related to ticks and spiders. Most mites are free-living and harmless. Other mites are parasitic, and those that infest livestock animals cause many diseases that are widespread, reduce production and profit for farmers, and are expensive to control.

<i>Hypoderma tarandi</i> Species of fly

Hypoderma tarandi, also known as the reindeer warble fly and reindeer botfly, is a species of warble fly that is parasitic on reindeer.

<i>Cephenemyia trompe</i> Species of fly

Cephenemyia trompe, also known as the reindeer nose botfly, is a species of botfly first described by Adolph Modéer in 1786. It belongs to the deer botflygenus Cephenemyia. This fly is parasitic on reindeer. It is one of two Cephenemyia species found only in Scandinavia.

Cordylobia rodhaini, also known as the Lund's fly, derived its common name from captain Lund, who was the first European to show symptoms of the disease caused by the larvae of the same fly. Lund’s fly belongs to the genus Cordylobia, flies from the family Calliphoridae. The larvae of the Lund’s fly are parasites of thinned-skinned mammals, especially the Gambian rat, mona monkey and small antelopes and are only accidental parasites of humans. The adult flies feeds on rotting fruits, vegetables and animal feces, and are most abundant in the wet season. Like many tropical insects they are most active in the dark periods and have the greatest activity early in the morning and late in the evening while resting typically between 8am to 5pm. The Lund’s fly are largely confined to tropical Africa, especially the rainforest areas in Sub-Saharan Africa. As a result of human migration, though, the parasitic infections they cause have been recorded in other continents, including Europe and Asia.

Parasitic flies of domestic animals

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.

<i>Cuterebra fontinella</i> Species of fly

Cuterebra fontinella, the mouse bot fly, is a species of New World skin bot fly in the family Oestridae. C. fontinella is typically around 1 cm (0.39 in) in length with a black and yellow color pattern. C. fontinella develops by parasitizing nutrients from its host, typically the white-footed mouse. C. fontinella has even been known to parasitize humans in rare cases. Individuals parasitized by C. fontinella will develop a large bump on the skin that is indicative of parasitization.

Cattle drenching

Cattle drenching is the process of administrating chemicals solutions (anthelmintics) to cattle or Bos taurus with the purpose of protecting livestock from various parasites including worms, fluke, cattle ticks, lice and flies. Parasites hinder the production of cattle through living off their host and carrying diseases that can be transmitted to cattle. Cattle drenches can be applied through a solution poured on the back, throat or an injection. Cattle drenches are predominately necessary for young cattle with weaker immune systems that are susceptible to parasite infestation. Drenching is a common method for controlling parasites in the meat and dairy industries. Drenching cattle improves the health, condition and fertility of cattle leading to increased calving rates, weight gain, hide condition and milk production.

Leif Reinhardt Natvig was a Norwegian entomologist. He was employed throughout his entire career at the Oslo Zoological Museum, and he contributed to a stronger connection between the museum and the Norwegian Entomological Society.

References

  1. The Merck Veterinary Manual.
  2. 1 2 Piper, R. (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals. Greenwood Press.
  3. Style, F. W (1924). "The Larva of the Warble-Fly as a Human Parasite". British Medical Journal. 1 (3312): 1086–1087. doi:10.1136/bmj.1.3312.1086. PMC   2304562 . PMID   20771637.
  4. Kalelioğlu, M.; et al. (December 1989). "Intracerebral myiasis from Hypoderma bovis larva in a child. Case report". J. Neurosurg. 71 (6): 929–931. doi:10.3171/jns.1989.71.6.0929. PMID   2585086.
  5. 1 2 Lagacé-Wiens, P. R.; et al. (2008). "Human ophthalmomyiasis interna caused by Hypoderma tarandi, Northern Canada". Emerging Infectious Diseases. 14 (1): 64–6. doi:10.3201/eid1401.070163. PMC   2600172 . PMID   18258079.
  6. "Defra website (archive): Warble fly".
  7. "Explanatory Note to the Animal Health (Miscellaneous Revocations)(England and Wales) Order 2015".