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ABSTRACTS
A record of Trichinella spiralis (Owen. 1835). P. A. MAPLESTONE and
N. V. BHADURI (1942). Indian Medical Gazette, 77, 193.
A LTHOUGH the existence of Trichinella spiralis in India has been suggested by Baylis
so far no authentic record of its occurrence either in man or animals in India has
been available. The authors have in the past few years made a systematic search for
this parasite in 100 pigs, 100 dogs and 100 rats, all without success but in the 74th cat
they found a large number of larvæ of Trichinella spiralis. This record suggests the
possibility of human and animal infections which have so far passed unnoticed. In
their search for the parasite, the authors employed the following technique:—
Either the whole or a portion of the diaphragm, where this parasite is generally found
in large numbers, was finely minced, placed in artificial gastric juice and incubated over-
night at 37°C. Then it was put in a fine wire sieve and extracted after Bærmann's method.
This method is claimed to be better than direct microscopical examination of ' press '
preparations.
The authors then briefly describe the parasitological, clinical and prophylactic aspects
of the infection, revealing how after ingestion the encysted larvæ in insufficiently cooked
pork get rid of their cyst wall in the digestive juices of the host and become sexually
mature in the mucous membrane and villi of intestines, gaining contact with lymphatic
and small blood vessels.
In about three days larval production begins and the rate of this increases for five
or six days and then steadily declines. The females die and are dealt with by phagocytes.
The larvæ measuring about 100 µ in length and 6 µ in breadth find their way to striated
muscles, especially the diaphragm, intercostal and muscles of mastication and degluti-
tion. There they become surrounded by migratory cells and then encapsulated, assuming
an ova shape with their axis parallel to the muscle fibres. They lie coiled in the cyst and
live for many years, until they die or become calcified.
The authors then describe three stages of the disease, commencing from the time of
infection, incubation and migration of parasite until the death of the host. In the first
stage the symptoms simulate those of cholera, dysentery or food poisoning. In the
second stage the high temperature and muscular pain give suspision of influenza, typhoid
or enteric fever. In the third stage the host sinks into a state closely resembling a severe
enteric fever.
The excretion of toxin by the larvæ brings about severe pathological lesions in myo-
cardial tissue and the central nervous system. Recovery takes place when the excretion
ceases on encystment of larvæ. Experimental work on Trichinella spiralis in America
established the possibility of transmission of infection to the fœtus in utero in guinea pigs
and of active and passive immunization of animals.
Diagnosis of trichinelliasis is difficult in the initial stage but the history of ingestion
of pork by the patient a day or two previously is of special value. Presence of' splinter '
hæmorrhage under the nails is a common sign. In the second or third week of the disease
serological tests for antibodies may be performed.
Cases of average severity generally recover although pain and stiffness may remain
for good. Death may occur to 33 per cent of cases. No specific treatment exists but
palliative treatment consists in administration of calcium or calcium gluconate to ensure
quick calcification of cysts.
All domesticated carnivorous animals are susceptible to infection and probably rats,
acting as a reservoir, may frustrate all practical attempts to eradicate the disease from
endemic areas, but the pig is the direct source of danger to man. In practice, it is not
found feasible to prevent lightly infected pork passing the most careful meat inspection.
So consumption of clean and well-cooked pork is essential as a preventive measure and the
practice of feeding uncooked or infected pork to domesticated animals also should be
condemned. [S. K. S.].