Human helminth infection

Eligh lgG4 responses in human helminth infection... 

The Potential of Geographical Information Systems (GIS) and Remote Sensing in the Epidemiology and Control of Human Helminth Infections... 

The BZAs have been developed as broad-spectrum anthelmintic agents. The most useful have modifications at the 2 and/or 5 positions of the benzimidazole ring system (Table 41-1). Thiabendazole, mebendazole, and albendazole have been used extensively for the treatment of human helminth infections. 

A. caninum, Uncinaria stenocephaia). Occasionally A, caninum larva may migrate to the human intestine causing eosinophilic enteritis this may happen when larva is ingested rather than through skin invasion. It is the second most common human helminthic infection (after ascariasis). Worldwide distribution, mostly in areas with moist, warm climate. Both N. americanus and A. duodenale are found in Africa, Asia, and the Americas. N. americanus predominates in the Americas and Australia, while only A, duodenale is found in the Middle East, North Africa, and southern Europe. 

Doetze A, Satoguina J, Burchard G et al. Antigen-specific cellular hyporesponsiveness in a chronic human helminth infection is mediated by Th3/Trl-type cytokines IL-10 and transforming growth factor- but not by a 1hl to Th2 shift Int Immunol 2000 12 623-630. 

The balance of evidence indicates that parasite-specific IgE may contribute to immediate hypersensitivity phenomena and parasite-directed inflammatory reactions (ADCC) in human helminth infections. IgE-induced mast cell degranulation may play a significant role in the allergic phenomena associated with early or acute infections in recruitment of effector cells to the tissue sites of helminth parasites, although the effectiveness of these mechanisms in parasite killing is not clear. The intense inflammation that results is the principal cause of the tissue pathology and clinical disease associated with these infections. In the absence of IgE, it is probable that other immunoglobulin isotypes can participate in ADCC reactions with similar efficiencies. Observations from primary infections with helminths in humans indicate that IgE is unlikely to have a critical role in host... 

Mahanty S, Abrams JS, King CL, Limaye AP, Nutman TB. Parallel regulation of lL-4 and IL-5 in human helminth infections. J Immunol 1992 148 3567-3571. 

Over the last several years, substantial progress in the discovery and development of anthelmintic dmgs has been made. Effective agents are available for most human gastrointestinal infections (Table 1) however, dmgs that are effective in treating the extraintestinal complications of many helminthic infections are still needed. 

The morbidity and mortality that are often associated with human GI helminth infections reflect in part the nutritional consequences of diarrhoea and malabsorption, and the resulting malnutrition that can accentuate the effects of infection by suppressing the protective immune response as well as compromising intestinal repair (Ferguson et al., 1980 Keymer and Tarlton, 1991 Cooper et al, 1992). In experimental rodents the pathology associated with infection is characterized by villus atrophy, crypt hyperplasia, goblet cell hyperplasia and infiltration of the mucosa by a variety of... 

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-... 

Some of the common anthelmintics used to kill the basic types of worms in humans are listed in Table 35-5. These agents are often very effective a single oral dose is usually sufficient to selectively destroy the parasite. Brief descriptions of the basic pharmacologic effects and possible adverse effects of the primary anthelmintic agents are presented below. Several authors have also extensively reviewed the pharmacologic treatment of helminthic infections.36,41,52,58,66... 

Helminth infections of humans are rarely immediately life-threatening. Competing health care demands in poor countries, including basic nutrition, sanitation, HIV infection and tuberculosis, dwarf the demand for better control of worms. 

Three major groups of helminths (or worms), the nematodes, trema-todes and cestodes, infect humans. As in all antibiotic regimens, the anthelminthic drugs (Figure 36.1) are aimed at metabolic targets that are present in the parasite but are either absent from or have different characteristics than those of the host. Figure 36.2 illustrates the high incidence of helminthic infections. 

Infections with Taenia, a genus belonging to the family of tapeworms, is of no consequence for the human liver and bile ducts. In contrast, echinococcosis is a helminthic infection of major clinical significance. 

A variety of helminths belonging to the class nematoda (roundworms), trema-toda (flatworms or flukes) and cestoda (tapeworms) are known to infect humans and domestic animals. The diseases caused by these worms are not only responsible for occasional deaths and wide range of health problems in man, but also exert detrimental effect on the nutritional and immune status of the host resulting in low resistance against other infections. The presence of helminth infections in livestock leads to decrease in output of animal products (milk, fat, butter, meat, eggs, wool and leather etc.) and has, therefore, strong socio-economic impact in countries with agro-and dairy-based industries [7]. 

Although quite a good number of compounds containing arsenic, antimony, phosphorus and other metals have been found to display a wide spectrum of activity against protozoal and helminth infections in humans and domestic animals, they find limited use in current therapy because of their high toxicity, low therapeutic indices and availability of better drugs. 

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