WBabesia bovis is a single-celled parasite of cattle which occasionally infects humans. It is a member of the phylum Apicomplexa, which also includes the malaria parasite. The disease it and other members of the genus Babesia cause is a hemolytic anemia known as babesiosis and colloquially called Texas cattle fever, redwater or piroplasmosis. It is transmitted by bites from infected larval ticks of the order Ixodida. It was eradicated from the United States by 1943, but is still present in Mexico and much of the world's tropics. The chief vector of Babesia species is the southern cattle fever tick Rhipicephalus microplus.
WBabesia divergens is an intraerythrocytic parasite, transmitted by the tick Ixodes ricinus. It is the main agent of bovine babesiosis, or "redwater fever", in Europe. Young cattle are less susceptible. The current emphasis in Europe on sustainable agriculture and extensification is likely to lead to an increase in vector tick populations with increased risk of infection. B. divergens is also prevalent in cottontail rabbits on Nantucket Island, MA, USA.
WCorynosoma autrale is a species of acanthocephalan. This species usually infects pinnipeds; the semi-aquatic fin-footed marine mammals most commonly known as seals and sea lions. Pinniped infections are not exclusive, recently C. australe has been discovered in Magellanic penguins.
WDicrocoelium dendriticum, the lancet liver fluke, is a parasite fluke that tends to live in cattle or other grazing mammals.
WNeospora is a single celled parasite of livestock and companion animals. It was not discovered until 1984 in Norway, where it was found in dogs. Neosporosis, the disease that affects cattle and companion animals, has a worldwide distribution. Neosporosis causes abortions in cattle and paralysis in companion animals. It is highly transmissible and some herds can have up to a 90% prevalence. Up to 33% of pregnancies can result in aborted fetuses on one dairy farm. In many countries this organism is the main cause of abortion in cattle. Neosporosis is now considered as a major cause of abortion in cattle worldwide. Many reliable diagnostic tests are commercially available. Neospora caninum does not appear to be infectious to humans. In dogs, Neospora caninum can cause neurological signs, especially in congenitally infected puppies, where it can form cysts in the central nervous system.
WSarcocystis is a genus of parasites, the majority of species infecting mammals, and some infecting reptiles and birds.
WTheileria parva is a species of parasites, named in honour of Arnold Theiler, that causes East Coast fever (theileriosis) in cattle, a costly disease in Africa. The main vector for T. parva is the tick Rhipicephalus appendiculatus. Theiler found that East Coast fever was not the same as redwater, but caused by a different protozoan.
WTritrichomonas foetus is a species of single-celled flagellated parasites that is known to be a pathogen of the bovine reproductive tract as well as the intestinal tract of cats. In cattle, the organism is transmitted to the female vagina and uterus from the foreskin of the bull where the parasite is known to reside. It causes infertility, and, at times, has caused spontaneous abortions in the first trimester. In the last ten years, there have been reports of Tritrichomonas foetus in the feces of young cats that have diarrhea and live in households with multiple cats. Tritrichomonas foetus looks similarly to Giardia and is often misdiagnosis for it when viewed under a microscope.
WTrypanosoma brucei is a species of parasitic kinetoplastid belonging to the genus Trypanosoma. The parasite is the cause of a vector-borne disease of vertebrate animals, including humans, carried by genera of tsetse fly in sub-Saharan Africa. In humans T. brucei causes African trypanosomiasis, or sleeping sickness. In animals it causes animal trypanosomiasis, also called nagana in cattle and horses. T. brucei has traditionally been grouped into three subspecies: T. b. brucei, T. b. gambiense and T. b. rhodesiense. The first is a parasite of non-human vertebrates, while the latter two are the known parasites of humans. Only rarely can the T. b. brucei infect a human.
WTrypanosoma congolense is a species of trypanosomes and is the major pathogen responsible for the disease nagana in cattle and other animals including sheep, pigs, goats, horses and camels, dogs, as well as laboratory mice. It is the most common cause of nagana in east Africa, but is also a major cause of nagana in west Africa. This parasite is spread by tsetse flies. In its mammalian host, Trypanosoma congolense only lives in blood vessels, and causes in particular anaemia.
WTrypanosoma cruzi is a species of parasitic euglenoids. Amongst the protozoa, the trypanosomes characteristically bore tissue in another organism and feed on blood (primarily) and also lymph. This behaviour causes disease or the likelihood of disease that varies with the organism: Chagas disease in humans, dourine and surra in horses, and a brucellosis-like disease in cattle. Parasites need a host body and the haematophagous insect triatomine is the major vector in accord with a mechanism of infection. The triatomine likes the nests of vertebrate animals for shelter, where it bites and sucks blood for food. Individual triatomines infected with protozoa from other contact with animals transmit trypanosomes when the triatomine deposits its faeces on the host's skin surface and then bites. Penetration of the infected faeces is further facilitated by the scratching of the bite area by the human or animal host.
WTrypanosoma evansi is a species of excavate trypanosome in the genus Trypanosoma that causes one form of surra in animals. It has been proposed that T. evansi is—like T. equiperdum—a derivative of T. brucei. Due to this loss of part of the mitochondrial (kinetoplast) DNA T. evansi is not capable of infecting the invertebrate vector and establishing the subsequent life-stages. Due to its mechanical transmission T. evansi is not restricted to transmission via the tsetse fly but shows a very broad vector specificity including the genera Tabanus, Stomoxys, Haematopota, Chrysops and Lyperosia. It rarely causes disease in humans, indeed, it has only been recorded in cases where the patient lacks a normal component of human serum, Apolipoprotein L1. T. evansi is very common in India and Iran and causes acute disease in camels and horses, and chronic disease in cattle and buffalo. In Pakistan, it has been found to be the most prevalent trypanosome species in donkeys.