44              Incidence of Strongyloides papillosus Wedl, 1856

            THE RHABDITIFORM (FREE-LIVING) MALE

It could not be detected during the culture studies made with calf faeces.
The free-living males are reported to be more common in faecal cultures of
rabbits harbouring Strongyloides papillosus. Infection of rabbits is con-
templated ; the one attempted failed.

                                PATHOGENESIS

Strongyloides papillosus occurs in cattle, sheep and goats, many wild
ruminants and the rabbit. In sheep it is not considered very pathogenic,
many being harboured without apparent ill-effects. In the mink, from which
similar forms are recovered, heavy infections are found to cause serious trouble.

During post mortem of a dozen calves counts varying from a few to a
thousand-and-five-hundred of these worms, in the small intestine, have been
detected. It should be possible in the tropics, for young stock to get very
heavily infested with these worms. Few of the young calves escape being in-
fected as findings show. Unthriftiness among calves is common and in the
absence of other accountable causes, it may be useful to investigate if that
could be attributed to parasitism by Strongyloides.

                                    IMMUNITY

There seems to be an age immunity of cattle against Strongyloides judg-
ing from the results of faecal examination of calves and full grown cattle.
Sixty per cent of 150 young calves were found infested with Strongyloides
papillosus; but no infection was observed in 400 adults aged two years and
over. It appears that infected calves quickly cleanse themselves with the
growing of age.

                          ACKNOWLEDGEMENT

The author is indebted to Rao Sahib M. Anant Narayan Rao, Lecturer
in Parasitology, Madras Veterinary College, for helpful criticism, facilities
and guidance, generously given for this piece of work.

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