Blood fluke infections

Blood fluke infections in cattle, sheep and goat are common in Africa, China and India. Some important flukes invading the blood circulatory system of cattle, sheep and goats are Schistosoma bovis, S. mattheei, S. nasalis, S. indicum, S. japonicim and S. spindale. 

Manger, P., Li, J., Christensen, B.M. and Yoshino, T.P. (1996) Biogenic monoamines in the freshwater snail, Biomphalaria glabrata influence of infection by the human blood fluke, Schistosoma mansoni. Comparative Biochemistry and Physiology A - Physiology 114, 227-234. 

The trematodes (flukes) are leaf-shaped flatworms that are generally characterized by the tissues they infect. For example, they may be categorized as liver, lung, intestinal, or blood flukes. 

Viral, parasitic, and bacterial infections have been linked to cancer (Table 9). DNA viruses such as Epstein-Barr, hepatitis B, hepatitis C, papillomaviruses, and Kaposi sarcoma herpes virus and RNA viruses such as human T-cell leukemia virus type I and human immunodeficiency virus have been implicated in causing cancer in humans and are listed as known-to-cause-cancer in humans by the International Agency for Research on Cancer (lARC). In man, the liver fluke, Opisthorchis viverrini, is associated with the development of cholangiocarcinomas of the liver and the blood fluke. Schistosoma haematobium, with carcinoma of the urinary bladder. There is evidence that chronic Helicobacter pylori infection of the stomach in man is not only related to... 

Parasitic helminth (worm) infections are widespread and may be the most common disease in the world. Estimates by the WHO and others are that one type of schistosomiasis, the blood flukes, has 200 million people infected. Ascaris, a large roundworm, accounts for at least 650 million, hookworm 450 million, and the several filarial worm species add another 250 million victims to the total. The situation has improved little in the past decade. 

These are the main species of blood flukes that cause human schistosomiasis, which affects about 200 million people. Schistosomiasis is widely distributed over South America (. mansoni), much of Africa and the Arabian Peninsula (S. mansoni and S. haematobium), and China and Southeast Asia (S. japonicum). Infected snails are intermediate hosts for freshwater transmission. Schistosomiasis primarily involves the liver, spleen, and GI tract (S. mansoni and S. japonicum) or the lower genitourinary tract (S. haematobium). Heavy infections with S. haematobium are associated with bladder carcinoma. Chronic infections can cause portosystemic shunting due to periportal fibrosis in the liver. 

The medically important trematodes include schistosoma species (blood flukes, estimated to affect over 150 milhon persons, worldwide), Clonorchis sinensis (liver fluke, endemic in Southeast Asia), tind Paragonimus westennani (lung fluke, endemic to both Asia and the Indian subcontinent). With few exceptions, fluke infections respond well to praziquantel. 

Cercarial dermatitis, or swimmer s itch , is caused by cercariae of blood flukes that infect animals, usually birds, rodents, or ungulates. It presents as an intensely pruritic self-limited maculopapular eruption, lasting approximately 1-2 weeks (Baird and Wear 1987). In contrast to sea-bather s eruption, cercarial dermatitis... 

The hciokworm is a parasitic worm. It is a common source of anemia in warm climates, including the southern United States. The parasitic worms are classed as flukes (trematodes), tapeworms (cestodes), and roundworms (nematodes). Tapeworms, for example, are mentioned under Vitamin B 2 in Chapter 9. The hookworm is a roundworm. It enters the body via the skin, that is, bare feet. The hookworm resides in the lumen of the small intestines w here it attaches itself to the villi. This results in damage to the villi, blood losses, secondary infections by other microoi anisms, and inflammation. The roundworm secretes anticoagulants that promote continued bleeding. Each worm may be responsible for the loss of up to 0.25 ml of blood per day. Hb levels as low as 20 mg/ml have been associated with hookworm infections. The disease can be prevented by the sanitary disposal of feces and by wearing shoes. 

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