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Trichinella spiralis Historical aspect   In 1835, a man died of tuberculosis in St Bartholomew’s Hospital, London. Dr Paget, a first-year student, carried out the autopsy and observed fine hard white inclusions in the muscles. Similar inclusions had been observed by doctors from time to time in the past, but were attributed to...

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BLOOD AND TISSUE NEMATODES INTRODUCTION Filariasis is caused by nematodes (roundworms) that inhabit the lymphatics and subcutaneous tissues. Eight main species infect humans. Three of these are responsible for most of the morbidity due to filariasis: Wuchereria bancrofti and Brugia malayi cause lymphatic filariasis, and Onchocerca volvulus causes onchocerciasis (river blindness). The other...

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  Life cycle of Human Hookworms Pathology of Infection.      The Pathology associated with hookworm infections may be divided roughly into two areas. Firstly the pathology associated with the presence of the adult parasite in the intestine, and secondly the pathology associated with the penetration of, and migration of the larval worms within...

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The human hookworms   introduction     The hookworms belong to the Order Strongylida, a large order, and of great interest as it contains many important pathogens of man and domesticated animals. This order is further subdivided into three Superfamilies, the Strongyloidea (the hookworms in man), and two related groups, the Superfamily ‘Trichostrongyloidea’, intestinal...

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SOIL TRANSMITTED HELMINTHS  INTRODUCTION    Soil-transmitted helminth (STH) infection is highly endemic in tropical and subtropical areas of sub-Saharan Africa, Asia and Latin America, where up to 2 billion people have active infections. STH disease has mainly remained neglected by the global health community because the people most affected are among the most...

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GENERAL FEATURES AND LIFE CYCLES OF NEMATODES INTRODUCTION Nematode infections in humans include ascariasis, trichuriasis, hookworm, enterobiasis, strongyloidiasis, filariasis, and trichinosis, among others. The phylum Nematoda, also known as the roundworms, is the second-largest phylum in the animal kingdom, encompassing up to 500,000 species. Members of Nematoda are elongated, with bilaterally symmetric bodies...

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Echinococcus spp     Three species of Echinococcus have been generally accepted as parasites of man Echinococcus granulosus    The causative agent of Hydatid disease in man and many other mammals. The dog acts as the definitive host for this species. A number of sub-species of this parasite have also been described, the...

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Pathology of Infection of Taenia     T. saginata Larvae - Unlike T. solium, T. saginata does not utilise man as an intermediate host, and therefore pathology due to the larval form is not a feature in human disease. In cattle, the cysticercus, referred to as Cysticercus bovis (named before the parasite life...

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TAPEWORMS OF MAN AND OTHER HUMAN’S CESTODES INTRODUCTION   Two species from the genus Taenia are common parasites of man, these being Taenia solium (the Pork tapeworm) and Taenia saginata (the Beef tapeworm). Taenia saginata has a cosmopolitan distribution, with estimates of approximately 50 million cases of infection world-wide annually. As with T....

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H. diminuta - The Rat Tapeworm    This tapeworm is much longer than H. nana, growing up to 60cm or more in length. This is primarily a parasite of the rat, humans only being infected by accidental ingestion of the insect intermediate host. This species is of more importance as a research model...

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TAPEWORMS AND EXAMPLES INTRODUCTION     Cestodes or tapeworms are the most specialised of the Platyhelminthe parasites. All cestodes have at least one, and sometimes more than one, secondary or intermediate host as well as their primary host. While the intermediate hosts are often invertebrates of some sort, the primary host is normally a...

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Larval Metacercaria The Larval Cestodes 1) The Cestodarians      The custodian's larvae or lycophore are free swimming, being covered in cilia. They have a set of ten hooks at the extreme anterior of the body, thus differing from the larval cestodes, which are equipped with 3 pairs of hooks. Anteriorly they are...

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  BASIC BODY PLAN OF A CESTODE INTRODUCTION The cestodes consist of two separate subclasses, the Cestodarians, parasites of fish and other cold-blooded vertebrates. These are non-segmented parasites, with only a single set of sexual organs. In contrast, the more well-known members of the Subclass Eucestoda are parasites of both warm and cold-blooded...

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