228 DISEASES DUE TO HELMINTHS 



DISEASES DUE TO HELMINTHS. 



GENERAL REMARKS. 



The animals causing disease in man are from three king-doms, 

 viz. : Animal, Protista or Intermediate, and Vegetable. 



We are concerned here with the former or Animal kingdom, which 

 for convenience is divided into the : — 



Sub-kingdom i, Protozoa, and the Sub-kingdom 2, Metazoa. 



The Protozoa are dealt with in another section. 



All Metazoa are multicellular, free-living, or parasitic animals, 

 having groups of cells to perform definite functions and are sometimes 

 referred to as the Animal kingdom in a restricted sense. 



The parasitic metazoa may be ectoparasites as insects, mosquitoes, 

 &c., or endoparasites as helminths. 



The Metazoa parasitic for man are classified thus : — 



Phylum (i) Platyhelmia. 

 ,, (2) Nemathchnia. 

 ,, (3) Annulata. 

 ,, (4) Arthropoda. 



In this section we shall deal with those Platyhelmia and Nemat- 

 helmia pathogenic to man. These are principally to be found among- 

 the Trematodes (Flukes), Cestodes (Tapeworms), and Nematodes 

 (Threadworms) . 



DISTRIBUTION. 



Some helminths are found everywhere, such as the Ascaris 

 lumbricoides, Oxyuris vermicularis, Trichocephalus dispar and others. 



Others are prevalent where dogs and sheep abound, as the 

 Taenia echinococcus in Australia; Flukes are found ^hiefl^' in Asia, 

 Filaria volvulus in West .Africa, and the Gastrodiscus in Assam. 



The ankylostomes are restricted to warm climates where the}' can 

 obtain plenty of moisture, or to warm temperatures in other countries 

 in the presence of moisture as in the Cornwall mines. 



Factors controlling the Distribution (Leiper). 



(i) General sanitary measures and personal hygiene. 



The latter measure thoroughly carried out would stamp out 

 Oxyuris in six weeks. The eggs are laid about the buttocks, 

 re-infection taking place by the eggs getting in the finger nails. 



(2) The preparation of food. 



Trichinosis is common where fresh-water lish and insufticientlv 

 cooked food are eaten. 



