Strongyloides stercoralis is a human pathogenic parasitic roundworm causing the disease strongyloidiasis. Its common name in the US is threadworm. In the UK and Australia, however, the term threadworm can also refer to nematodes of the genus Enterobius, otherwise known as pinworms.
A parasitic disease, also known as parasitosis, is an infectious disease caused by parasites. Parasites are organisms which derive sustenance from its host while causing it harm. The study of parasites and parasitic diseases is known as parasitology. Medical parasitology is concerned with three major groups of parasites: parasitic protozoa, helminths, and parasitic arthropods. Parasitic diseases are thus considered those diseases that are caused by pathogens belonging taxonomically to either the animal kingdom, or the protozoan kingdom.
Parasitology is the study of parasites, their hosts, and the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question but by their way of life. This means it forms a synthesis of other disciplines, and draws on techniques from fields such as cell biology, bioinformatics, biochemistry, molecular biology, immunology, genetics, evolution and ecology.
Abamectin (also called avermectin B1) is a widely used insecticide and anthelmintic. Abamectin, is a member of the avermectin family and is a natural fermentation product of soil dwelling actinomycete Streptomyces avermitilis. Abamectin differs from ivermectin, the popular member of the avermectin family, by a double bond between carbons 22 and 25. Fermentation of Streptomyces avermitilis yields eight closely related avermectin homologs, with the B1a and B1b forms comprising the majority of the fermentation. The non-proprietary name, abamectin, refers to a mixture of B1a (~80%) and B1b (~20%). Out of all the avermectins, abamectin is the only one that is used both in agriculture and pharmaceuticals.
Ivermectin is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, it is used to treat infestations including head lice, scabies, river blindness (onchocerciasis), strongyloidiasis, trichuriasis, ascariasis and lymphatic filariasis. It works through many mechanisms to kill the targeted parasites, and can be taken by mouth, or applied to the skin for external infestations. It belongs to the avermectin family of medications.
Doramectin, sold under the brand name Dectomax among others, is a veterinary medication approved by the US Food and Drug Administration (FDA) for the treatment of parasites such as gastrointestinal roundworms, lungworms, eyeworms, grubs, sucking lice, and mange mites in cattle. It is available as a generic medication. It is available as a combination with levamisole under the brand name Valcor.
Ascaridia galli is a parasitic roundworm belonging to the phylum Nematoda. Nematodes of the genus Ascaridia are essentially intestinal parasites of birds. A. galli is the most prevalent and pathogenic species, especially in domestic fowl, Gallus domesticus. It causes ascaridiasis, a disease of poultry due to heavy worm infection, particularly in chickens and turkeys. It inhabits the small intestine, and can be occasionally seen in commercial eggs.
Moxidectin is an anthelmintic drug used in animals to prevent or control parasitic worms (helminths), such as heartworm and intestinal worms, in dogs, cats, horses, cattle, sheep and wombats. Moxidectin kills some of the most common internal and external parasites by selectively binding to a parasite's glutamate-gated chloride ion channels. These channels are vital to the function of invertebrate nerve and muscle cells; when moxidectin binds to the channels, it disrupts neurotransmission, resulting in paralysis and death of the parasite.
Uncinaria stenocephala is a nematode that parasitizes dogs, cats, and foxes as well as humans. It is rare to find in cats in the United States. Uncinaria stenocephala is the most common canine hookworm in cooler regions, such as Canada and the northern regions of the US, where it can be found primarily in foxes (40%). U. stenocephala is also one of the most common hookworms in the UK, called the northern hookworm, however it has a rather low prevalence. U. stenocephala is also considered to be zoonotic hookworms because they live in animals but can be transmitted to humans.
Levamisole, sold under the brand name Ergamisol among others, is a medication used to treat parasitic worm infections, specifically ascariasis and hookworm infections. It is taken by mouth.
The avermectins are a series of drugs and pesticides used to treat parasitic worm infestations and to reduce insect pests. They are a group of 16-membered macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties. These naturally occurring compounds are generated as fermentation products by Streptomyces avermitilis, a soil actinomycete. Eight different avermectins were isolated in four pairs of homologue compounds, with a major (a-component) and minor (b-component) component usually in ratios of 80:20 to 90:10. Avermectin B1, a mixture of B1a and B1b, is the drug and pesticide abamectin. Other anthelmintics derived from the avermectins include ivermectin, selamectin, doramectin, eprinomectin.
Thelazia callipaeda is a parasitic nematode, and the most common cause of thelaziasis in humans, dogs and cats. It was first discovered in the eyes of a dog in China in 1910. By 2000, over 250 human cases had been reported in the medical literature.
Anthelmintics or antihelminthics are a group of antiparasitic drugs that expel parasitic worms (helminths) and other internal parasites from the body by either stunning or killing them and without causing significant damage to the host. They may also be called vermifuges or vermicides. Anthelmintics are used to treat people who are infected by helminths, a condition called helminthiasis. These drugs are also used to treat infected animals, particularly small ruminants such as goats and sheep.
Oxfendazole is a broad spectrum benzimidazole anthelmintic. Its main use is for protecting livestock against roundworm, strongyles and pinworms. Oxfendazole is the sulfoxide metabolite of fenbendazole.
Teladorsagia circumcincta is a nematode that is one of the most important parasites of sheep and goats. It was previously known as Ostertagia circumcincta and is colloquially known as the brown stomach worm. It is common in cool, temperate areas, such as south-eastern and south-western Australia and the United Kingdom. There is considerable variation among lambs and kids in susceptibility to infection. Much of the variation is genetic and influences the immune response. The parasite induces a type I hypersensitivity response which is responsible for the relative protein deficiency which is characteristic of severely infected animals. There are mechanistic mathematical models which can predict the course of infection. There are a variety of ways to control the infection and a combination of control measures is likely to provide the most effective and sustainable control.
Amphistomiasis is a parasitic disease of livestock animals, more commonly of cattle and sheep, and humans caused by immature helminthic flatworms belonging to the order Echinostomida. The term amphistomiasis is used for broader connotation implying the disease inflicted by members of Echinostomida including the family Paramphistomidae/Gastrodiscidae ; whereas paramphistomiasis is restricted to that of the members of the family Paramphistomidae only. G. discoides and Watsonius watsoni are responsible for the disease in humans, while most paramphistomes are responsible in livestock animals, and some wild mammals. In livestock industry the disease causes heavy economic backlashes due to poor production of milk, meat and wool.
Halicephalobus gingivalis is a free-living saprophagous nematode species identified and named in 1954 by Stefanski. It is a facultative parasite of horses, invading the nasal cavity, and sometimes numerous other areas, where it produces granulomatous masses. On rare occasion, it can infect humans as well, in whom it is invariably fatal. Based on studies performed on infected horses in Florida, the parasite is associated with swampland environments. These worms are dioecious, with female and male organs having been found in separate individuals. Eggs and immature larvae have been found in tissue samples, indicating an asexual reproductive cycle, and free-living males have been found in soil environments, indicating that sexual reproduction also occurs. The site of entry for the parasite is thought to be through breaks in the skin or through mucous membranes. This nematode is now distributed worldwide, as cases of equine infections have been found in Canada, Florida, the Nordic regions, and Arabian horses alike.
Cooperia oncophora is one of the most common intestinal parasitic nematodes in cattle in temperate regions. Infections with C. oncophora may result in mild clinical symptoms, but can lead to weight loss and damage of the small intestine, especially when co-infections with other nematodes such as O. ostertagi occur. Infections are usually treated with broad-spectrum anthelmintics such as benzimidazole, but resistance to these drugs has developed in the last decades and is now very common. C. oncophora has a direct life cycle. Infective larvae are ingested by the host. The larvae grow to adults, which reproduce in the small intestines. Eggs are shed onto the pasture with the faeces, which leads to new infections. Co-infections with other gastro-intestinal nematodes such as O. ostertagi and H. contortus are common.
Cattle drenching is the process of administering chemical 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.
Monepantel is an anthelmintic approved for use in sheep and cattle to control gastrointestinal nematodes. It belongs to a new class of anthelmintics called aminoacetonitrile derivatives (AAD). It is marketed by Elanco as Zolvix as a single active, or Zolvix Plus in combination with the macrocyclic lactone abamectin.
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