Adult worms of the rural strain of Wuchereria bancrofti in Peninsular Malaysia obtained from a successful experimental transmission in an immunosuppressed Macaca fascicularis are described for the first time. Although the worms, especially females, were slightly smaller, they were similar in morphology to those of the periodic and non-periodic W. bancrofti previously described.
The prevalence of Capillaria hepatica (Bancroft, 1893) infection in a total of 2324 rats trapped from 25 localities in West Malaysia was 15.5%. Infection rates in males (16.0%) and females (15.1%) are similar. A significantly higher percentage of adults (18.1%) than young (7.7%) was infected. Capillaria hepatica infection rates among urban (0.7%) and jungle (0.0%) rats was very low as compared to field rats (17.7%) trapped from agricultural areas such as oil palm estates and rice growing areas. Prevalence of C. hepatica infection in rats is not evenly distributed throughout West Malaysia. There seem to be localised foci of infection. In some areas as many as 77.8% of the adult rats are found to be infected while in other areas the same species of rats are found free of infection.
Six species of strigeoid trematodes are reported from Malaysia. One new genus and 3 new species are described: Apatemon (Apatemon( jamesi sp. n (Strigeidae); cercaria Cotylurus sullivani sp. n. (Strigeidae); Neodiplostomum (Neodiplostomum) sp. (Diplostomatidae); Fibricola ramachandrani (Diplostomatidae); Pseudoscolopacitrema otteri gen. n. et sp. n. (Diplostomatidae); and cercaria Cyathocotyle malayi sp. n. (Cyathocotylidae). The life cycles of A. jamesi and C. malayi have also been investigated.
This paper reports the experimental transmission of a bird parasite into jirds. Infective larvae of Cardiofilaria nilesi obtained from laboratory colonized Coquillettidia crassipes mosquitoes which had fed on an infected chicken were inoculated subcutaneously into jirds. The number of larvae per jird varied from 10 to 228. Microfilaraemia appeared 22 to 89 days after inoculation of the infective larvae. Experiments were carried out with 24 jirds through six generations extending over a period of 22 months and 17 produced patent infections. At present 8 infected jirds are being maintained in the laboratory; their patent periods ranging from 6 to 13 months. However, the longest patent period observed was about thirteen months. The percentage of adults recovered in autopsied jirds ranged from 0 to 40 with an average of 16. The chicken showed a microfilarial periodicity with the peak microfilarial density around 2200 hours. However, in jirds there was a change in sub-periodicity. This model in the jird may be very useful for the screening of filaricides and in immunological work.
The lung fluke, Paragonimus westermani (Kerbert, 1878), is widely distributed in Asia, and exhibits much variation in its biological properties. Previous phylogenetic studies using DNA sequences have demonstrated that samples from north-east Asia form a tight group distinct from samples from south Asia (Philippines, Thailand, Malaysia). Among countries from the latter region, considerable molecular diversity was observed. This was investigated further using additional DNA sequences (partial mitochondrial cytochrome c oxidase subunit 1 (COI) and the second internal transcribed spacer of the nuclear ribosomal gene repeat (ITS2)) from additional samples of P. westermani. Phylogenies inferred from these again found three or four groups within P. westermani, depending on the method of analysis. Populations of P. westermani from north-east Asia use snail hosts of the family Pleuroceridae and differ in other biological properties from populations in south Asia (that use snail hosts of the family Thiaridae). It is considered that the populations we sampled can be divided into two species, one in north-east Asia and the other in south Asia.
Mesocoelium malayanum sp. n. is described from the frog Rana macrodon, in Malaysia. Elongate body, broader anteriorly, measuring 1.900 (1.679-2.070) mm long by 0.404 (0.380-0.437) wide, tegument aspinose oral sucker 0.212 (0.200-0.228) by 0.202 (9.191-0.205), acetabulum 0.141 (0.132-0.150) by 0.139 (0.123-0.146), prepharynx present, oesophagus 0.115 (0.096-0.137), caeca reaching posterior 1/3 of body, anterior testis 0.097 (0.087-0.110) by 0.091 (0.087-0.100) dorsal to acetabulum, posterior testis 0.094 (0.087-0.101) by 0.092 (0.091-0.100), cirrus pouch 0.121 (0.111-0.130) by 0.047 (0.041-0.055), genital pore at left of midline of oesophagus just anterior to intestinal bifurcation, ovary 0.110 (0.091-0.127) by 0.089 (0.085-0.096) on left of body and posterior to acetabulum, vitelline glands with single follicles extending from intestinal bifurcation to ends of caeca, excretory vesicle I-shaped and eggs 0.040 (0.037-0.046) by 0.023 (0.022-0.024). Although morphologically related to M. maroccanum and M. meggitti, M. malayanum is considered to be a new species.
Stunkardia minuta sp. n. was recovered from the small intestine and rectum of 5 box-tortoises (Cuora amboinensis) in Malaysia. The average body size (L X W) is 11-42 X 2-35 mm; oral sucker 1-51 X 1.02; oral pouches 0-21 X 0.18; ventral sucker 1-67 X 1-43; oesophageal bulb 0-54 X 0-54; ant. testis 0-95 X 0-98; post. testis 0-94 X 0.94; seminal vesicle 0-82 X 0-24; ootype 0-21 X 0-41; ovary 0-41 X 0-34; and egg 121 X 83 micrometer. Although morphologically similar to S. dilymphosa, S. minuta is distinct from any other reported member of the Paramphistomidae.
Examination of naturally infected felids and viverrids in Malaysia confirmed previously published records which indicated that P. westermani occurred only in felid cats. Felis planiceps and F. temnickli were reported as new host records. Analysis of stomach contents revealed no crab remains in either family of cats, but confirmed that felids were strictly carnivorous while viverrids were often omnivorous. In feeding experiments, only viverrids ate the host crabs Potomiscus johorensis and Parathelphusa maculata. The probable transmission of P. westermani to felids via paratenic hosts was discussed.
Neodiplostomum (Conodiplostomum) ramachandrani sp. n. is described from Rattus muelleri in Kepong, Selangor, Malaysia. It is characterised by having symmetrical dumbell-shaped testes, and vitellaria as a single ventral band in the hindbody. The taxonomic relations of Neodiplostomum, Conodiplostomum and Fibricola are discussed and possible significance of the fluke as an ecological indicator noted.
The development of Breinlia booliati is described in its natural host, Rattus sabanus and in an inbred strain of laboratory albino rat. The growth of the parasite is similar in both the rat hosts. The third moult occurs between six-eight days and the final moult between 24-28 days. Larvae were recovered initially from the skin and carcass. After five weeks, developing stages were seen only in the thoracic and abdominal cavities, the site of development of the adult worms. Worms became sexually mature by 11-12 weeks and there was considerable growth in length of the female worms after this stage.
Breinlia booliati exhibited nocturnal subperiodicity in its natural host, Rattus sabanus in contrast to experimentally infected laboratory-reared albine rats which showed irregular fluctuations of microfilariae throughout the 24 hour cycle. All the infected albino rats showed a prepatent period between 11-14 weeks postinoculation. Three patterns of microfilaraemia were discerned during the course of infection 38/49 rats displayed a single peak, 4/49 displayed 2 peaks about 12-15 weeks apart and 7/49 showed a sustained high plateau-like pattern of microfilaraemia. Cortisone had no effect on microfilarial levels when administered to rats near postpatency and some at postpatency.