Vol 27 No 2 December - The Indian Society for Parasitology
Vol 27 No 2 December - The Indian Society for Parasitology
Vol 27 No 2 December - The Indian Society for Parasitology
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70 Trematodes of public health importance<br />
JPD : <strong>Vol</strong>. <strong>27</strong> (2), 2003<br />
number of parasites will be encountered in an<br />
infection. <strong>The</strong>se embrass digestion and at times cause<br />
acute obstruction. Toxic metabolites cause edema of<br />
face, of the abdomen and lower extremities. <strong>The</strong>re will<br />
be characteristic notable eosinophilia. <strong>The</strong>re is often<br />
leucocytoses with eosinophilia upto 35%.<br />
Occasionally there may be leucopenia with<br />
lymphocytosis. (Hafeez 1993)<br />
AMPHISTOMATE FLUKES<br />
In domestic animals large number of species of<br />
amphistomes have been described from the rumen<br />
reticulum and bile duct of Ruminants and some species<br />
occur in the large intestine of equines, pigs and man.<br />
(Faust et al 1975, Hafeez 1993)<br />
Gastrodiscoides hominis<br />
It is relatively common human parasite, which was<br />
recorded from the intestine of pig and man by various<br />
workers. It has been incriminated that Helicorbis<br />
coenosus to be the intermediate host of this fluke.<br />
Cercariae probably encyst as metacercariae in aquatic<br />
vegetations after emerging from the snails as in case of<br />
F. buski. Exposure of the definite host results from<br />
consumption of infested grass/ vegetation or other<br />
plants. (Faust et al 1975)<br />
Besides the damage caused by the immature flukes<br />
after encystment in small intestine , the worms inhabit<br />
the caecum and ascending colon, where it also cause<br />
mucous diarrhoea in man.<br />
Dutt and Srivastava (1966) studied the life cycle of G.<br />
hominis - <strong>The</strong>y have incriminated Helicorbis coenosus<br />
to be the intermediate host of this fluke. <strong>The</strong> different<br />
larval stages in the snail has been studied. Cercariae<br />
probably encyst as metacercariae in aquatic<br />
vegetations after emerging from the snails as in case of<br />
F. buski. Exposure of the definitive host results from<br />
consumption of infested grass/vegetation or other<br />
plant vectors.<br />
Watsonius Watsoni<br />
It has been obtained only once from man, a West<br />
African Negro who died of severe diarrhoea. At<br />
necropsy many worms were found attached to the<br />
duodenal and jejunal mucosa and free in the large<br />
bowel. Monkeys are also considered to be the natural<br />
hosts. Infection of the final host is by ingestion of the<br />
metacercariae with herbage. Outbreaks of<br />
Paramphistomiasis generally occur in the drier<br />
months. <strong>The</strong> snail population becomes concentrated<br />
around area of natural water, and these areas in the dry<br />
months, also have the most palatable grazing and thus<br />
there is a concentration of cattle, snails and<br />
metacercariae over a small area leading to heavy<br />
infections. Previous infection and the age of the host<br />
af<strong>for</strong>d some protection against reinfection and hence<br />
acute disease is usually seen in young animals while<br />
older animals, capable of withstanding massive<br />
exposure, seed the pastures with eggs.<br />
ECHINOSTOMATE FLUKES<br />
Echinoparayphium paraulum<br />
It occurs in the small intestine of duck, the pigeon and<br />
man. <strong>The</strong> 1st Intermediate Host is the snail and some<br />
nd<br />
authors suspect fish and snails as 2 int. host.<br />
Echinochasmus ilocanum<br />
It occurs in the small intestine of man. It has also been<br />
found in the dog and <strong>No</strong>rway rat; the latter serving as a<br />
reservoir host. <strong>The</strong> 1st Intermediate Hosts are snails of<br />
Gyraulus convexiculus, G.prashadhi and Hippeutis<br />
umbillicali Cercariae encyst on almost any fresh water<br />
mollusc but Pila luzomica, P .conica and Viviparus<br />
nd<br />
javanicum are especially important (as 2 I.H.),<br />
because they are regarded as a delicacy and are eaten<br />
raw or at the most with the sprinkling of salt.<br />
According to Anantaraman (1967), Indoplanorbis and<br />
Lymnea spp. may function as the first and Pila (or any<br />
fresh water fish) as the second int. host. (Faust et al<br />
1975, Pathak 1991)<br />
Artifechinostomum sufrartyfex<br />
Occurs in man, pig, dog, and rat in India.<br />
Indoplanorbis exustus acts as 1st and the same snail<br />
may act at II nd Int. host. Indoplanorbis and Lymnea<br />
spp. may function as the first and pila (or any fresh<br />
water fish) as the second, I.H.<br />
HETEROPHYID FLUKES<br />
Heterophyes heterophyes<br />
It is common parasite found in the small intestine of<br />
man, dog, fox, cat etc. <strong>The</strong>y also act as reservoir hosts.<br />
<strong>The</strong> 1st intermediate host are the snails spirenella<br />
conica in Egypt and Cerithidia cingulata in Japan.