Infective larvae of Wuchereria, Brugia, Breinlia, Dirofilaria and Setaria species from an experimental vector, Aedes togoi, are compared. The distinctive bubble-like caudal papillae of Wuchereria bancrofti are readily distinguishable from the protuberant ones of Brugia spp; the 'ear-like' papillae of Breinlia are distinct from the 'knob-like' ones of Dirofilaria or the 'thorn-like' terminal papilla of Setaria.
A collection of parasitic worms was made from Rattus rattus jarak (Bonhote) from Pulau Jarak, “which lies in the middle of the Malacca Straits between Penang and Port Swettenham and some 85 miles from the Sembilan Islands opposite the Dindings.” (Audy, 1950). It was collected by Dr. J. R. Audy, Senior Research Officer of the Division of Virus Research and Medical Zoology, Institute for Medical Research, Kuala Lumpur while investigating scrub-typhus on the island.
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.
Hard structures of helminths have often been used for taxonomic identification but are usually not clearly defined when treated with conventional methods such as ammonium picrate-glycerin for monogeneans and glycerin for nematodes. The present study reports a rapid and simple technique to better resolve the hard parts of selected monogeneans and nematodes using 5-10% alkaline sodium dodecyl sulphate (SDS). In comparison with established methods, SDS-treated worms become more transparent. In monogeneans treated with SDS, clear details of the hooks, hook filaments, anchors, bars and the sclerotized copulatory organs could be observed. In SDS-treated nematodes, spicules and ornamentations of the buccal capsules could be clearly seen.
Ligophorus belanaki n. sp. and Ligophorus kederai n. sp. are described from Liza subviridis Valenciennes, 1836 and Valamugil buchanani Bleeker, 1854, respectively. Ligophorus kederai n. sp. has fenestrated ventral anchors, while in L. belanaki n. sp. the ventral anchor is not fenestrated. Ligophorus belanaki n. sp. is similar to L. careyensis, one of its coexisting congeners, in the overall shape and size of hard parts, but differs in having a flat median piece in the structure of the AMP (antero-median protuberance of the ventral bar), copulatory organ with non-ornamented initial part and longer vaginal tube, compared to raised median piece in the AMP, ornamented initial part and comparatively shorter vaginal tube in L. careyensis. Ligophorus kederai n. sp. is similar to L. fenestrum, a coexisting congener, in having fenestrated ventral anchors, but differs in having longer points and narrower base. Ligophorus fenestrum, unlike L. kederai n. sp., also possesses fenestrated dorsal anchors. The principal component analysis (PCA) scatterplots indicate that the two new and eight known Ligophorus species from Malaysian mugilids can be differentiated based on the morphometries of their anchors, ventral bars and copulatory organ separately and when combined together. Numerical taxonomy (NT) analyses based on Jaccard's Index of Similarity and neighbour-joining clustering, is used to facilitate comparison of these two new species with the 50 known Ligophorus based on morphological and metric characters. The two new species are different from each other and the other 50 species in the overall shapes and sizes of hard parts, as indicated by the NT analyses.
Angiostrongylus mackerrasae is a parasitic nematode of rats found in Australia. When first reported, it was referred to as A. cantonensis. Recent molecular studies, including the mitochondrial genome, indicate that it is highly similar to A. cantonensis. These studies did not include A. malaysiensis, another member of the A. cantonensis species complex, for comparison. The present study examined the genetic distance and phylogenetic relationship between the component taxa (A. cantonensis, A. mackerrasae and A. malaysiensis) of the A. cantonensis species complex, based on the 12 protein-coding genes (PCGs) of their mitochondrial genome. Both the nucleotide and amino acid sequences were analysed. Angiostrongylus mackerrasae and A. cantonensis are members of the same genetic lineage and both are genetically distinct from A. malaysiensis. The genetic distance based on concatenated nucleotide sequences of 12 mt-PCGs between A. mackerrasae and A. cantonensis from Thailand is p = 1.73%, while that between the Thai and Chinese taxa of A. cantonensis is p = 3.52%; the genetic distance between A. mackerrasae and A. cantonensis from China is p = 3.70%. The results indicate that A. mackerrasae and A. cantonensis belong to the same genetic lineage, and that A. mackerrasae may be conspecific with A. cantonensis. It remains to be resolved whether A. mackerrasae is conspecific with A. cantonensis or undergoing incipient speciation.
Fifty children aged 6 to 13 years and infected with Ascaris lumbricoides were selected for the study. The number of eggs laid daily by a female Ascaris increased with increase in its length, weight and diameter. Female worms became mature and started laying eggs when they reached a length of 118 mm. Adult female worms measuring 3.7 mm or more in diameter were found to be mature. The minimum weight of a worm producing eggs was 1.1 g. On average the number of eggs produced by the female decreased with increase in the worm load.
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.
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.
Human dirofilariasis is a rare infection in Malaysia. Thus far, only two human cases have been reported viz. Dirofilaria immitis and D. (Nochtiella) repens and in both instances, adult worms were recovered from infected patients. The two cases reported in the present study, one from Melaka and the other from Penang, were diagnosed histologically. Based on the diagnostic criteria for identifying Dirofilaria in tissue sections, the parasites were identified as D. (Nochtiella) repens.
The levels of nematode egg production in goats and the availability of infective larvae (L3) on pasture were investigated on a dairy unit in New South Wales, Australia. The output of eggs by adult goats was always above 300 epg. The profile of the graph of larval availability in herbage paralleled those for temperature and rainfall, suggesting that larval peaks occurred when the temperature and availability of moisture were optimal. The dominant genus was Trichostrongylus, followed by Haemonchus, then Ostertagia. A larger proportion of Haemonchus larvae in the cultures of faeces were collected during the summer months.
Thirteen bats, Tadarida mops de Blainville, collected from the Ampang district in Kuala Lumpur, Malaysia, were found positive for the trematodes Castroia kamariae sp. nov. and Limatulum kuziai sp. nov. Two distinct but morphologically similar forms of Castroia kamariae were recovered. The morphological type is apparently determined by its location in the host intestine.
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.
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.
Neodiplostomum (Conodiplostomum) ramachandrani Betterton, 1976 has been reported from four species of rodent hosts: Echinosorex gymnurus (Raffles): Rattus whiteheadi (Thos); R. muelleri (Jentink) and Callosciurus notatus (Boddaert). A comparison of trematodes recovered from these hosts revealed patterns of host-induced morphological variation taking place. Because N. (Conodiplostomum) ramachandrani shows little generic difference from Fibricola intermedius (Pearson, 1959) Sudarikov, 1960 it is transferred to the genus Fibricola and is now designated Fibricola ramachandrani (Betterton, 1976) Palmieri, Krishnasamy and Sullivan.