WORM INCIDENCE 
25 
The worm parasites which are of no obvious medical or veterinary importance have been 
largely neglected in Malaya. A few records exist of parasitic worms collected from Malayan 
hosts which have found their way into the Zoological Gardens in other parts of the world. 
The writer (1950, 1951) reported on parasites of certain Primates, including the Orangutan, and 
a series of observations on Malayan worm parasites is included in this Study (p. 195, 
Sandosham 1953 &&)• The Colonial Office Scrub Typhus Research Unit has published a 
preliminary note on worms from rats from Jarak Island (Audy et al. 1950, p. 256). The 
following were common : Capillaria ( Hepaticola ) hepatica , Rictularia sp., a Nippostrongylus 
sp. (J. J. C. Buckley det), and peculiar strongyloids which were found in the liver. 
Present Studies 
A survey to establish the present-day infection rates of the common human worms and 
to determine the parasites of domestic and wild animals is being undertaken in the Department 
of Parasitology of the University of Malaya and the writer hopes to publish shortly a check-list 
of worm parasites recorded in this country. 
The Colonial Office Research Unit is investigating the biology and ecology of carrier mites 
and their animal hosts. Collecting small mammals, especially rats and insectivores, and 
identifying the ectoparasites is fundamental to the whole scheme of this investigation. Oppor- 
tunity has been taken to make a thorough and complete examination of as large a number of 
each species as possible of these animals for endoparasites. These worm parasites are in the 
process of being sorted out but it is felt that the Table below, giving the total numbers of 
endoparasites grouped as Nematodes, Cestodes, Trematodes and Acanthocephala, for each 
species, will be of some value in assessing the degree of worm infection in these hosts. As yet, 
the number of hosts examined, with the exception of a dozen species, is too few to enable sound 
conclusions to be drawn on the intensity of infection. Even so, a glance at the Table suggests 
that the rats of the woods and forests like Rattus rattus jalorensis, R. whiteheadi, R. miilleri and 
R. rajah are less heavily parasitised than the house-frequenting forms associated with towns 
like R. rattus diardii and R. norvegicus. Similarly, R. exulans caught in houses in Singapore 
are more heavily infected than those caught in wasteland on the mainland. The comparatively 
heavy infection of R. r. diardii by Acanthocephala is doubtless associated with the diet, these 
helminths being acquired by eating cockroaches, grubs, etc. The collection of worms is being 
continued so that the endoparasites of a representative sample of a wide variety of animals will 
be available for study. When these worms have been identified and their mode of transmission 
determined there should emerge an interesting ecological picture of the host-parasite relations 
with the environment and mode of fife of the host. 
Summary 
Previous investigations of helminth infections in man and animals in Malaya are 
summarised up to date. In the case of human infections, the importance of hookworm was 
recognised very early, and great improvements in its control followed the findings of a 
Commission in 1915. Filariasis is known to be very severe locally and to extend even to 
Aborigines deep in the hinterland. Two species of Mansonia have been shown to transmit 
the infection. cc Sawah-itch ” is known to be caused by Schistosoma spindale and members of 
the “ elvae ” group. A number of studies of helminth infections of animals — e.g. “aortic 
worms ”, filariasis, onchocerciasis — are summarised. It is noteworthy that Dirofilaria immitis 
has been recovered from the orangutan. 
Recent studies of helminths from animals collected by the Colonial Office Research Unit 
are described briefly and the results are provisionally tabulated. Investigations continue on 
these infections. 
MALA YA, No. 26, 1953 
