Helminth parasite infection

T-Cell Regulation in Helminth Parasite Infections Implications for Inflammatory Diseases... 

Helminth parasites infect a broad range of species, including man and it is estimated that a third of the global population is infected with parasitic worms. In this chapter, we focus solely on parasitic helminths, which have a medical significance to humans. These species include the Digenean flukes of the Class Trematoda (Flatworms) and the Class Cestoda (Tapeworms), both of the phylum Platyhelminthes and the phylum Nematoda (Roundworms). Some of the major species of helminths of medical importance to humans are outlined in Table 1, presented with an arbitrary ranking based on prevalence of worldwide infections. 

Antiparasitic drugs are used for the treatment of parasitic infections caused by pathogenic protozoa or helminths (worms). 

Infections with helminth parasites remain extraordinarily prevalent in many developing countries, with >25% of the human population currently infected. Helminth diseases are also... 

Pearce EJ, Kane C, Sun J, J JT, McKee AS, Cervi L Th2 response polarization during infection with the helminth parasite Schistosoma mansoni. Immunol Rev 2004 201 117-126. 

IgG is the characteristic antibody of all internal secretions including blood and cerebrospinal fluid (CSF). Normal urine contains about 5-10 mg/day. In secondary immune responses like malaria and helminth infection, very large quantities of IgG are produced especially to soluble antigens and toxins. High values are found in many parasitic infections. 

Rodriguez-Sosa, M., Rosas, L.E., David, J.R., Bojalil, R., Satoskar, A.R. and Terrazas, L.l. (2003b) Macrophage migration inhibitory factor plays a critical role in mediating protection against the helminth parasite Taenia crassiceps. Infection and Immunity 71, 1247-1254. 

The pharmacologic treatment of parasitic infections is a complex and extensive topic. In this limited space, it is difficult to describe the many species of each parasite, all the diseases caused by parasites, and the chemical methods currently available to selectively destroy various fungi, protozoa, and helminths in humans. Consequently, the general aspects of each type of parasitic infection are reviewed briefly, followed by the primary drugs used to treat specific fungal, protozoal, and helminthic infections. This discussion will acquaint physical therapists and occupational ther-... 

In its general scientific sense, the term "parasite" includes all of the known infectious agents such as viruses, bacteria, fungi, protozoa, and helminths. In this and the two following chapters, the term is used in a restricted sense to denote the protozoa and helminths. It has been estimated that 3 billion (3 x 109) humans suffer from parasitic infections, plus a much greater number of domestic and wild animals. Although these diseases constitute the most widespread human health problem in the world today, they have for various reasons also been the most neglected. 

In spite of the widespread occurrence of slgA, not only in cestode infections, but in all other helminth intestinal infections, the role played by IgA remains unknown (921). In relation to this, it has been speculated (53) that IgA antibody is relevant in the control of the uptake of parasite antigens, their clearance from the circulation and in the modulation of the activities of various cells in the inflammatory events associated with infections this may involve enhancement of cytotoxic functions or the minimization of potentially pathogenic reactions. ... 

Applying the protective role of parasite infection against inflammatory disorders, over the years a wide range of helminths and their derived products have been associated with the potential to modulate autoimmunity and allergic disorder, approaching the therapeutic wiudow. 

Thiabendazole. This benzimidazole derivative (12) is an effective oral drug used in the treatment of intestinal roundworms and selected tissue parasites. Infections with S. stercorahs are commonly treated with thiabendazole for two days. Disseminated strongyloidiasis is treated for at least five days. Satisfactory results have been reported when used for T. spirahs infections however, its effectiveness on encapsulated muscle larvae has not been clinically demonstrated. Extensively used in veterinary medicine, thiabendazole was the first broad-spectrum benzimidazole anthelmintic. It is widely used in the United States. The mechanism of action is not clearly understood, but it has been shown that thiabendazole inhibits the enzyme fiima.ra.te reductase, which is found specifically in the mitochondria of helminths (31). 

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. 

Other protozoal infections (e.g., giardiasis, leishmaniasis, and malaria) and helminths are less common eye pathogens in the United States. Systemic pharmacological management as well as vitrectomy may be indicated for selected parasitic infections. 

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