Encysted Health Dictionary

Trichinosis, or trichiniasis, is a disease caused by eating meat infected with the parasitic nematode worm, Trichinella spiralis. Although it infects more than 100 animal species, this nematode usually infects humans via pig meat in which the immature spiralis is encysted. The full-grown female worm, which inhabits the intestine, is 3 mm in length, and the larvae, to whose movements the disease is due, are much smaller. The disease is acquired by eating raw or underdone pork from pigs that have been infected with the worm. When such a piece of meat is eaten, the embryos contained in it are set free and develop into full-grown trichinellae; from each pair of these, 1,000 or more new embryos may arise in a few weeks. These burrow through the walls of the gut, spread throughout the body and settle in voluntary muscle.

Prevention is based on thorough inspection of meat in slaughterhouses; even cooking, unless the meat is in slices, is not an e?cient protection. Pigs should not be fed on unboiled garbage. Rats may be a source of sporadic outbreaks, as infected rats have been found near piggeries. The disease is widely distributed throughout the Americas, Asia, Africa and the Arctic. Sporadic cases and epidemics occur and outbreaks also appear in Europe, although rarely in Britain.

Treatment Thiabendazole or mebendazole are usually e?ective, while STEROID treatment helps patients with systemic illness and muscle tenderness.... trichinosis

pl. n. (sing. bacterium) a group of microorganisms all of which lack a distinct nuclear membrane (and hence are considered more primitive than animal and plant cells) and most of which have a cell wall of unique composition (many antibiotics act by destroying the bacterial cell wall). Most bacteria are unicellular; the cells may be spherical (*coccus), rod-shaped (*bacillus), spiral (*Spirillum), comma-shaped (*Vibrio), or corkscrew-shaped (*spirochaete). Generally, they range in size between 0.5 and 5 ?m. Motile species bear one or more fine hairs (flagella) arising from their surface. Many possess an outer slimy *capsule, and some have the ability to produce an encysted or resting form (*endospore). Bacteria reproduce asexually by simple division of cells; incomplete separation of daughter cells leads to the formation of *colonies consisting of different numbers and arrangements of cells. Some colonies are filamentous in shape, resembling those of fungi. Transfer of DNA from one bacterium to another takes place in the process of *conjugation.

Bacteria are very widely distributed. Some live in soil, water, or air; others are parasites of humans, animals, and plants. Many parasitic bacteria do not harm their hosts; some cause diseases by producing poisons (see endotoxin; exotoxin).... bacteria