A light and electron microscopic study of Sarcocystis orientalis sp. n. was made. The life cycle of this parasite is in two hosts. Gametogony is in the intestinal epithelial cells of a predator, Python reticulatus. Isospora-like oocysts developed. Sporocysts average 9.1 by 7.7 mum. Rats (Rattus norvegicus) were infected with sporocysts and asexual stages developed. Ten days after infection large zoites (average 7.85 by 2.48 mum) were observed free in peripheral blood and within white blood cells. Small schizonts producing merozoites 2-3 mum long were seen in lung tissue. Tissue cysts developed in skeletal muscle and produced numerous cystozoites (average 5.53 by 1.38 mum). Fine structure was similar to previously described Sarcocystis spp.
R. sabanus and R. muelleri are very common in the lowland forests of Malaysia. In nature they are infected with Breinlia sp. and D. ramachandrani. In an attempt to determine whether they are also susceptible to subperiodic B. malayi and thereby being potential reservoirs of infection of the disease, 24 R. muelleri and 17 R. sabanus were experimentally infected with the parasite. Results show that although they can support the full development of the parasite, they are poor hosts. This confirms the observation that in Malaysia natural infection of Rattus spp. with the parasite has not been seen. These rats therefore are probably not important in the zoonotic transmission of subperiodic B. malayi in Malaysia.
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.
Numbers of L. (L.) deliense larvae were determined in adjacent habitats over a 16 month period. Both R. argentiventer and R. tiomanicus were highly efficient hosts for L. (L.) deliense. R. argentiventer was host to significantly greater numbers of chiggers per rat than was R. tiomanicus. The 2 habitats were similar in numbers of chiggers collected. No consistent correlation was apparent between numbers of chiggers and any single weather factor, but the chigger population seemed to be adversely affected by a 2 month period during which total evaporation greatly exceeded total rainfall. Direct fluorescent antibody examination of tissues from unfed L. (L.) deliense showed that 2 of 420 larvae (0.5%) contained organisms morphologically resembling R. tsutsugamushi. Considering the vector load and numbers of chiggers being returned to the ground by a given host, a rate of 0.5% appeared adequate to account for the prevalence rate of R. tsutsugamushi observed in the 2 host species.
Description of a new species of Oxyurid: Syphacia (Syphatineria) callosciuri n. sp. parasite of a Sciurid rodent Callosciuris caniceps in Malaysia. In rodents belonging to the genus Callosciurus in Malaysia two species: S callosciuri n. sp. and S. owyangi Quentin, 1975, show morphological characteristics which are intermediate between the primitive Syphacia and two different lines of species parasite of recent rodents. These observations appear to indicate that the adaptation of Syphacia of Sciurids to the modern rodents has occured in South-East Asia.
Rodents were collected from five wet markets (Chow Kit, Dato Keramat, Setapak, Jinjang and Kepong) in Kuala Lumpur, Federal Territory between March to April 2006. Ninety seven rats were trapped using wire traps measuring 29 x 22 x 50 cm baited with fruits, coconuts, dried fish or sweet potatoes. A total of 17 different species of parasites were identified from three species of rats out of which 11 (65%) were identified to be zoonotic. The helminths identified from the urban rats were nematodes- Capillaria hepatica, Gongylonema neoplasticum, Heterakis spumosa, Heterakis sp., Masterphorus muris, Nippostrongylus brasiliensis, Physolaptera sp., Pterogodermatis sp., Rictularia tani and Syphacia muris; cestodes- Hymenolepis nana, Hymenolepis diminuta, Hymenolepis sabnema, Hymenolepis sp., Raillietina sp. and Taenia taeniaeformis, and acanthocephalan- Moniliformis moniliformis. The following parasites are of potential medical importance: C. hepatica, G. neoplasticum, R. tani, S. muris, H. diminuta, H. nana, Raillietina sp. and T. taeniaeformis.
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.
The technique of isoenzyme electrophoresis was applied to Japanese wild populations of Taenia taeniaeformis (isolated from Norway rats) and three laboratory reared isolates (KRN isolated from a Malaysian Norway rat, BMM from a Belgian house mouse and ACR from a Japanese gray red-backed vole). The average heterozygosities of Japanese wild populations were fairly small and total genetic variability was 0.0499. The genetic make-up of T. taeniaeformis in Norway rats was rather uniform in the whole of Japan. In KRN isolate, each of all 10 loci examined possessed the allele which was predominant in Japanese wild populations. Similarly, each of 9 loci in BMM isolate possessed the same alleles, but one of 2 alleles at HK locus was different from that in the others. T. taeniaeformis parasitizing house mice and rats were considered to be genetically closely related to each other. In ACR isolate, 7 out of 10 loci possessed different alleles from those in the other populations. It was considered that ACR isolate was genetically distant and its phylogenetic origin in Japan should be different from worms parasitizing Norway rats.
Numerous studies have reported the prevalence of toxoplasmosis among Malaysians and various domestic animals; but there is paucity of information on its prevalence among rodents which could potentially contribute to the transmission of Toxoplasma gondii in both domestic and sylvatic fauna. Five hundred twenty-six rodents were captured from six locations in Malaysia and identified to species. Serum samples were collected from these rodents and tested for T.gondii antibodies using an immunofluorescent antibody test (IFAT). T.gondii antibodies were found in 5.9% (31/526) of the tested samples. Most of the positive antibodies were from commensal rats: Rattus exulans (9/64, 14.0%), Rattus argentiventer (2/8, 25%), Rattus rattus diardii (10/166, 6.0%) and Rattus tiomanicus (6/215, 2.7%). Only two of the forest rats were positive: Maxomys rajah (1/9, 11.1%) and Rattus bowersi (1/12, 8.3%). Eighteen point one percent of ground squirrels (Tupaia glis) tested (2/11) were positive for antibodies. The highest antibodies titer (1:1024) was found in Rattus exulans followed by T.glis (1:256). Sabak Bernam, Selangor had the highest prevalence (10.8%) followed by Baling, Kedah (5.0%) and Bagan Terap, Selangor (4.0%). None of the serum samples of rodents collected from Gua Musang, Kelantan; Jasin, Malacca; or Labis, Johor were positive. Our study reports for the first time the serologic prevalence of T.gondii antibodies among rodents in Peninsular Malaysia. Further studies are needed to confirm T.gondii infection among wild rodents, such as a bioassay, to assess their potential role in transmission of the parasite.
Taenia taeniaeformis were isolated from Norway rats captured at Sapporo (SRN isolate) and Kuala Lumpur, Malaysia (KRN) and from Bedford's gray red-backed voles at Toubetsu (TCR) and Abuta (ACR). SRN, KRN and TCR isolates showed similar degree of infectivity to various rodents in which cysticerci with hooks were obtained in laboratory rats, white tuberous lesions in mice and no cysts or lesions in Mongolian gerbils and voles. Contrary to this, inoculation with ACR isolate eggs resulted in strobilocerci formation in the liver of voles, but no cysts were observed in rats, mice or gerbils. This host specificity of ACR isolate to voles suggests that it might be a new species of Taenia.
The local Chow Kit market is the largest wet market in the city of Kuala Lumpur. It is very close to the biggest government hospital in the city centre. However, the level of cleanliness in this area is always questionable and a matter of concern. The aim of this study was to identify the prevalence of T. gondii oocyst in water samples used by hawkers in that market and tissue cysts in rats' brains captured from the same area. Water samples were taken to the parasitology laboratory at the National Universtiy of MalaysiaUniversity and a sugar flotation concentration method was used. Supernatant microscopical examination was then performed. A total of 752 slides were screened for the presence of T. gondii oocyst. A hundred rats wandering in the same area were also captured by the hawkers using mousetraps. After each animal was sacrificed, and an electric microtome was used to cut out serial sections 5 microm thick from the rat brains. The de-waxed tissue sections were stained by the progressive Haematoxylin and Eosin (H&E) stain for microscopical examination. A total of 1000 slides were screened under a light microscope to detect the presence of T. gondii brain cysts. All the water samples were found to be negative for T. gondii oocyst. Out of the 100 rats captured, three rats were found to possess T. gondii cysts in their brains. Water samples reflect minimal or no solid food contamination, while the 3% of positive brain cysts influence the researchers to broaden their investigations for future projects.
Angiostrongylus cantonensis Chen, was recovered from a field rat, Rattus tiomanicus from the East Coast of Peninsular Malaysia. The parasite constitutes the first reported record occurring in this country. Morphological character of the parasite are compared with the original description of A. cantonensis by Chen (1935), A. cantonensis from Formosa and A. malaysiensis from Malaysia.
Breinlia booliati Singh & Ho, 1973 first described from Peninsular Malaysia has been shown to infect a large range of murids ranging in distribution from southern Thailand, Peninsular Malaysia, Sarawak to Ciloto, Indonesia. Probably further work will reveal a greater host range as well as its geographical distribution. The vectors involved in its transmission need to be elucidated.
One hundred and fifty one house rats, Rattus rattus diardii from five different localities, Jinjang, Dato Keramat, Kuala Lumpur, Sungai Besi and Selayang Baru, were examined for parasites. Nineteen species of parasites were recovered. Hymenolepis diminuta and Nippostrongylus brasiliensis are the predominant species. The dominancy of the parasite species in the rats differed in each locality: Hymenolepis diminuta in Dato Keramat and Kuala Lumpur; Nippostrongylus brasiliensis in Sungai Besi; Gongylomena neoplasticum in Jinjang and Selayang Baru. The influences of human habitats on the parasite fauna of house rats are discussed.
There were a spate of recent complaints of insect bites and the entomological specimens received from various sources were identified to be those of cat flea (Ctenocephalides felis) and rat flea (Xenopsylla cheopis), the tropical bed-bug (Cimex hemipterus) and the dog louse (Heterodoxus spiniger). Only the fleas and the bed-bug are known to attack humans.
A helminthological examination of 367 wood rats, Rattus tiomanicus, in an oil-palm. estate 24 miles north of Kuala Lumpur conducted during 1973 revealed 8 species of helminths: 5 nematodes. Angiostrongylus malaysiensis (54.2% of the rats infected), Hepatojarakus malayae (48.5%), Nippostrongylus braziliensis (48.0%), Gongylonema neoplasticum (0.3%), Syphacia muris (17.7%); 3 cestodes, Hymenolepis diminuta (6.0%), Hymenolepis nana (7.6%), Hydatigera taeniaeformis (cysticercus) (12.0%) and 1 pentastomid, Armillifer sp. (nymph) (0.8%). Overall helminthic infection rates seemed to be higher than those previously reported in this host species.