Mermithids are the most common parasites of black flies and are associated with host feminization and sterilization in infected hosts. However, information on the species / lineage of black fly mermithids in Southeast Asia, including Malaysia requires further elucidation. In this study, mermithids were obtained from black fly larvae collected from 138 freshwater stream sites across East and West Malaysia. A molecular approach based on nuclear-encoded 18S ribosomal RNA (18S rRNA) gene was used to identify the species identity / lineage of 77 nematodes successfully extracted and sequenced from the specimens collected. Maximum likelihood and neighbor-joining phylogenetic analyses demonstrated five distinct mermithid lineages. Four species delimitation analyses: automated simultaneous analysis phylogenetics (ASAP), maximum likelihood Poisson tree processes with Bayesian inferences (bPTP_ML), generalized mixed yule coalescent (GMYC) and single rate Poisson tree processes (PTP) were applied to delimit the species boundaries of mermithid lineages in this data set along with genetic distance analysis. Data analysis supports five distinct lineages or operational taxonomic units for mermithids in the present study, with two requiring further investigation as they may represent intraspecific variation or closely related taxa. One mermithid lineage was similar to that previously observed in Simulium nigrogilvum from Thailand. Co-infection with two mermithids of different lineages was observed in one larva of Simulium trangense. This study represents an important first step towards exploring other aspects of host - parasite interactions in black fly mermithids.
The SEAMEO TROPMED Network is a regional cooperative network established in 1967 for education, training and research in tropical medicine and public health under the Southeast Asia Ministers of Education Organization. The Network operates through four Regional Centers with respective areas of specialization and host institutions: Community Nutrition/Tropmed Indonesia; Microbiology, Parasitology and Entomology/Tropmed Malaysia; Public Health/Tropmed Philippines; and Tropical Medicine/Tropmed Thailand. To train health workers, to support research on endemic and newly emerging diseases, and to advocate relevant health policies are the main functions of these centers. SEAMEO TROPMED Network in collaboration with the Faculty of Tropical Medicine, Mahidol University and other institutions has regularly organized the Seminar on Food-borne Parasitic Zoonoses every 3-5 years over the past 15 years. The Faculty of Tropical Medicine has organized the annual Joint International Tropical Medicine Meeting since 1996. Full papers of the presentations at these two meetings have been published as supplementary issues to the Southeast Asian Journal of Tropical Medicine and Public Health, an in-house journal of SEAMEO TROPMED Network. Recently, the Parasitology Association of ASEAN Countries has rotated the hosting of the ASEAN Congress of Parasitology and Tropical Medicine. These institutional and conference networks will enable closer links, to promote the health of people in the Southeast Asian region.
Angiostrongylus cantonensis is the main causative agent of human angiostrongyliasis. A sibling species, A. malaysiensis has not been unequivocally incriminated to be involved in human infections. To date, there is only a single report on the application of the partial 66-kDa protein gene sequence for molecular differentiation and phylogeny of Angiostrongylus species. Nucleotide sequences of the 66-kDa protein gene of A. cantonensis and A. malaysiensis from Thailand, as well as those of the laboratory strains of A. cantonensis from Thailand and Hawaii, A. cantonensis from Japan and China, A. malaysiensis from Malaysia, and A. costaricensis from Costa Rica, were used for the reconstruction of phylogenetic tree by the maximum likelihood (ML) method and the haplotypes by the median joining (MJ) network. The ML phylogenetic tree contained two major clades with a full support bootstrap value - (1) A. cantonensis and A. malaysiensis, and (2) A. costaricensis. A. costaricensis was basal to A. cantonensis and A. malaysiensis. The genetic distance between A. cantonensis and A. malaysiensis ranged from p = .82% to p = 3.27%, that between A. cantonensis and A. costaricensis from p = 4.90% to p = 5.31%, and that between A. malaysiensis and A. costaricensis was p = 4.49% to p = 5.71%. Both A. cantonensis and A. malaysiensis possess high 66-kDa haplotype diversity. There was no clear separation of the conspecific taxa of A. cantonensis and A. malaysiensis from different geographical regions. A more intensive and extensive sampling with larger sample size may reveal greater haplotype diversity and a better resolved phylogeographical structure of A. cantonensis and A. malaysiensis.
Hamatopeduncularia longiangusticirrata sp. nov. and H. petalumvaginata sp. nov. were collected from Arius maculatus and Nemapteryx caelata, respectively from Tanjung Karang, Peninsular Malaysia. Morphological and molecular investigations were carried out to ascertain the identity of the new species. The two new species differ from previously described Hamatopeduncularia species in the morphology of the male and female reproductive organs. Hamatopeduncularia longiangusticirrata sp. nov. possesses a long penis similar to H. elongata, H. longicopulatrix, H. brisbanensis, H. major and H. petalumvaginata sp. nov., but differs in having a thread-like tapering distal end and can be distinguished from H. brisbanensis and H. major in not having an accessory piece. Hamatopeduncularia longiangusticirrata sp. nov. is also unique in having an ornamented penis initial and a vaginal tube surrounded by fine hair-like structures. Hamatopeduncularia petalumvaginata sp. nov. possesses a simple penis without an accessory piece and a petaloid vaginal opening that resembles the arrangement of petals on a flower. Maximum likelihood trees were constructed from partial 28S and 18S rDNA sequences of the two new species and other ancylodiscoidids to reveal a strongly supported monophyletic branch consisting of the two new species for both markers. According to Lim's classification in 1996 of Hamatopeduncularia species penis type, H. petalumvaginata sp. nov. has been classified within the elegans-type and H. longiangusticirrata sp. nov. is proposed as the longiangusticirrata-type.
Acanthocheilonema delicata n. sp. (Filarioidea: Onchocercidae: Onchocercinae) is described based on adult filarioids and microfilariae obtained from subcutaneous connective tissues and skin, respectively, of Japanese badgers (Meles anakuma) in Wakayama Prefecture, Japan. No endemic species of the genus had been found in Japan. Recently, some filarioids (e.g., Acanthocheilonema reconditum, Dirofilaria spp., and Onchocerca spp.) have come to light as causative agents of zoonosis worldwide. The new species was readily distinguished from its congeners by morphologic characteristics such as body length, body width, esophagus length, spicule length, and the length of microfilariae. Based on the molecular data of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene, A. delicata n. sp. was included in the clade of the genus Acanthocheilonema but differed from two other congeneric species available for study, A. viteae and A. reconditum. Acanthocheilonema delicata n. sp. did not harbor Wolbachia. It is likely that the fauna of filarioids from mammals on the Japanese islands is characterized by a high level of endemicity.
Human zoonotic onchocercosis is caused by Onchocerca dewittei japonica, parasitic in wild boars (Sus scrofa leucomystax) in Japan. Previously, microfilariae longer than those of Onchocerca dewittei japonica were observed in skin snips from wild boars during the study of O. dewittei japonica. Moreover, the third-stage larvae (L3) of these longer microfilariae were obtained from the blackfly Simulium bidentatum after experimental injections. Based on morphometric and molecular studies, similar L3 were found in blackflies during fieldwork in Oita, Japan. However, except for O. dewittei japonica, adult worms of Onchocerca have not been found in wild boars. In this study, we discovered adult females of a novel Onchocerca species in the skin of a wild boar in Oita, and named it Onchocerca takaokai n. sp. Females of this new species had longer microfilariae and differed from O. dewittei japonica in terms of their morphological characteristics and parasitic location. The molecular characteristics of the cytochrome c oxidase subunit 1 and 12S rRNA genes of the new species were identical to those of the longer microfilariae and L3 previously detected, but they differed from those of O. dewittei japonica at the species level. However, both species indicated a close affinity among their congeners and Onchocerca ramachandrini, parasitic in the warthog in Africa, was basal in the Suidae cluster of the 12S rRNA tree.
A case of zoonotic onchocercosis has been found in a resident who lived in Iizuka City, Fukuoka Prefecture, Japan for some time. A 24-year-old male developed a painful nodule on the middle finger of his right hand. The nodule was surgically removed from the vagina fibrosa tendinis of the finger at Beppu Medical Center, Beppu City, Oita Prefecture in 2012. The causative agent was identified as a female Onchocerca dewittei japonica based on its histopathological characteristics. The identity of the filarioid has been confirmed by sequencing the cox1 gene. The present study indicates that the zoonotic onchocercosis caused by O. dewittei japonica has been concentrated in northeast Kyushu.
Reports of zoonotic infections with Onchocerca japonica (Nematoda: Filarioidea), which parasitizes the Japanese wild boar, Sus scrofa leucomystax, have recently increased in Japan. To predict the occurrence of infection in humans, it is necessary to determine the prevalence of O. japonica infection in the natural host animals. We investigated the presence of adult worms in the footpads, and of microfilariae in skin snips, taken from the host animals, between 2000 and 2018. Onchocerca japonica was found in 165 of 223 (74%) Japanese wild boars in Honshu and Kyushu. Among the nine regions studied, the highest prevalence of O. japonica infection was found in Oita, Kyushu, where 47 of 52 (90.4%) animals were infected. The ears were the predilection sites for O. japonica microfilariae. Adult worms of O. japonica were found more frequently in the hindlimbs than in the forelimbs of the host animals. Onchocerca takaokai was found in 14 of 52 (26.9%) Japanese wild boars in Oita. In Kakeroma Island among the Nansei Islands, both O. japonica and O. takaokai were isolated from the Ryukyu wild boar, S. s. riukiuanus. These observations could help predict future occurrences of human zoonotic onchocercosis in Japan.
An 11-year-old boy living in Otsu City, Shiga Prefecture, Kansai Region, Western Honshu, Japan had zoonotic onchocercosis. The patient developed a painful swelling on the little finger of his left hand. The worm detected in the excised mass had external transverse ridges but did not have inner striae in the cuticle. On the basis of the parasite's histopathological characteristics, the causative agent was identified as a female Onchocerca dewittei japonica (Spirurida: Onchocercidae). The species of the filarial parasite was confirmed by sequencing the cox1 gene of the parasite. The Japanese wild boar Sus scrofa leucomystax is a definitive host for O. dewittei japonica, which is then transmitted by blackflies as the vector to humans. The current case described occurred in the Kansai Region, Western Honshu, where such infections were previously not reported.
A 73-year-old man living in Kawamata-machi, Fukushima Prefecture, Northeastern Honshu, Japan, visited a hospital with complaints of a subcutaneous swelling that had developed on the back of his left hand. The nodule was surgically removed from the vagina fibrosa tendinis of his left forefinger. Based on the histopathological characteristics, the causative agent of this nodule was identified as a female Onchocerca dewittei japonica (Spirurida: Onchocercidae). The species identification was confirmed by cox1 gene sequencing of the worm tissues from paraffin-embedded sections of the nodule. Although 11 cases of zoonotic onchocercosis have previously been recorded in Kyushu and Western Honshu, Japan, the present findings represent the first human case of infection with O. dewittei japonica in Northeastern Honshu, Japan.
Haliotrema susanae sp. nov. is described from the gills of the pinecone soldierfish, Myripristis murdjan off Langkawi Island, Malaysia. This species is differentiated from other Haliotrema species especially those from holocentrids in having a male copulatory organ with bract-like extensions at the initial of the copulatory tube, grooved dorsal anchors and ventral anchors with longer shafts. The maximum likelihood (ML) analysis based on partial 28S rDNA sequences of H. susanae sp. nov. and 47 closely related monogeneans showed that H. susanae sp. nov. is recovered within a monophyletic clade consisting of only species from the genus Haliotrema. It is also observed that H. susanae sp. nov. forms a clade with H. cromileptis and H. epinepheli which coincides with a similar grouping by Young based on solely morphological characteristics. The morphological and molecular results validate the identity of H. susanae sp. nov. as belonging to the genus Haliotrema.
Bovine anaplasmosis is a major concern to cattle farming in most parts of the world. Anaplasmosis negatively impacts the profitability of cattle farming by reducing the production, reproduction, and draft ability of cattle. Here, we report results from a one-year cross sectional study to determine the epidemiology and the risk factors for Anaplasma marginale infection of cattle in Peninsular Malaysia. Examination of one thousand and forty five blood samples of apparently healthy cattle from forty-three farms in all the states of Peninsular Malaysia by polymerase chain reaction (PCR) assay revealed an overall prevalence of A. marginale infection of cattle of 72.6%, showing high endemicity of this heamoprotozoan among cattle in the country. Cattle breeds, production type, herd owner, herd size, management system, farm size, farm age, prophylactic treatment against blood parasites, presence of ticks, frequency of deticking, zones, closeness to forest, closeness to waste area, closeness to human settlement and closeness to body of water were the risk factors significantly associated (P
The whipworm Trichuris muris is known to be associated with various rodent species in the northern hemisphere, but the species identity of whipworm infecting rodents in the Oriental region remains largely unknown. We collected Trichuris of Muridae rodents in mainland and insular Southeast Asia between 2008 and 2015 and used molecular and morphological approaches to identify the systematic position of new specimens. We discovered two new species that were clearly distinct from T. muris, both in terms of molecular phylogenetic clustering and morphological features, with one species found in Thailand and another one in Borneo. We named the new species from Thailand as Trichuris cossoni and the species from Borneo as Trichuris arrizabalagai. Molecular phylogeny using internal transcribed spacer region (ITS1-5.8S-ITS2) showed a divergence between T. arrizabalagai n. sp., T. cossoni n. sp. and T. muris. Our findings of phylogeographically distinct Trichuris species despite some globally distributed host species requires further research into the distribution of different species, previously assumed to belong to T. muris, which has particular relevance for using these species as laboratory model organisms.
We describe Morishitium polonicum malayense n. subsp. from Asian glossy starlings (Aplonis panayensis strigata) (Horsfield, 1821) (Passeriformis: Sturnidae) caught in Malaysia. The trematodes had parasitized the air sacs and the thoracic and body cavities of 40 out of 67 (59.7%) birds examined. The specimens each had an oral sucker, a postpharyngeal genital pore, and tandem testes, but lacked a ventral sucker. The morphological characteristics of our specimens were similar to those of M. polonicum polonicum (Machalska, 1980) from Poland. However, the anterior extremity of vitelline follicles of the present specimens sometimes extended to the level of pharynx. The oral sucker width, oral sucker width/pharynx width ratio, and intertesticular space metrics differed from those of M. p. polonicum. The maximum-likelihood trees based on the cytochrome c oxidase subunit I (COI) and the internal transcribed spacer 2 (ITS2) sequences indicated that the species from the present study formed a sister group with M. p. polonicum from the Czech Republic. The p-distances of COI and ITS2 sequences between the present specimens and M. p. polonicum from the Czech Republic were 6.9-7.5% and 0.6%, respectively. These genetic divergences indicate the border for intra- or interspecific variation of digeneans. The definitive host species and geographical distribution of the current specimens were distinct from those of M. p. polonicum from Europe. We thus concluded that the present specimens are ranked as a new subspecies of M. polonicum, namely M. polonicum malayense n. subsp.
Soil-transmitted helminth (STH) infections are the most common intestinal parasitic infections of medical importance in humans. The infections are widely distributed throughout tropical and subtropical countries, particularly among disadvantaged and underprivileged communities. In Malaysia, STH infections is highly prevalent, especially among the indigenous groups. However, species identification through molecular studies is still lacking. Using molecular techniques, this study was conducted to identify STH species that infect humans. Faecal samples were collected from three Iban tribal longhouses in the rural area of Sarikei Division, Sarawak. Positive faecal samples by microscopy were subjected to PCR and sequenced for species identification. Based on the microscopy examination, the most prevalent STH infection was Ascaris, followed by hookworm and Trichuris. All microscopy-positive samples were then PCR-amplified. The amplicons were sequenced, aligned, and compared with other sequences in the GenBank database. The results showed that Ascaris lumbricoides was the predominant STH species, followed by Trichuris trichiura, Ancylostoma duodenale, and Necator americanus. Our findings were contradictory to past studies, as we showed that A. duodenale was more abundant than N. americanus. Socioeconomic improvement and health education programs should be included in the management and prevention of public health strategies against STH.
Strongyloides stercoralis infection can persist in the host for several decades, and patients with cancer and other clinical conditions who are exposed to immunosuppressive therapy are at risk of developing hyperinfection.
The male of Phlebotomus (Larroussius) betisi is described from Malayan caves. Several males have been caught in association with P. betisi females. Males and females have been associated by ecology, biogeography, morphology and molecular biology (homology of the ND4 mtDNA sequences).
This study examines the biological efficacy of four mosquito mat vaporizers each containing different active ingredients: prallethrin with PBO, dimefluthrin, prallethrin, and d-allethrin. The glass chamber assay was used to evaluate their efficacy on Aedes albopictus (Skuse) (Diptera: Culicidae) from nine districts in Selangor, Malaysia. Aedes albopictus exhibited different knockdown rates, with 50% knockdown times, KT50, varying from 1.19 to 2.00 min, 1.22 to 2.20 min, 1.39 to 5.85 min, and 1.39 to 1.92 min for prallethrin with PBO, dimefluthrin, prallethrin and d-allethrin, respectively. In general, all populations of Ae. albopictus were completely knocked down after exposure to all active ingredients except Hulu Selangor population, which showed 96.00% knockdown against d-allethrin. On the contrary, mortality rates were observed from 84.00-100.00%, 84.00-100.00%, 90.67-100.00% and 90.67-100.00% in populations tested with prallethrin with PBO, dimefluthrin, prallethrin and d-allethrin, respectively. Moreover, significant correlations between mortality rates of prallethrin with PBO vs dimefluthrin (r = 0.836, P = 0.003), prallethrin with PBO vs prallethrin (r = 0.760, P = 0.011), and prallethrin vs d-allethrin (r = 0.694, P = 0.026) were also observed, suggesting cross-resistance among pyrethroids. d-allethrin was found to be high in insecticidal activity, followed by prallethrin, prallethrin with PBO, and dimefluthrin. In consistent with mortality due to insecticide exposure, elevated levels of enzyme activities were also demonstrated in Sabak Bernam, Hulu Selangor, Gombak, Petaling, Hulu Langat and Klang populations.
This report describes the detection of zoonotic Cryptosporidium muris, C. parvum subgenotype IIa and Giardia duodenalis genotype B in urban rodents in Malaysia. A rare occurrence of C. meleagridis was also reported suggesting a role of rodents in mechanical transmission of this pathogen. Utilization of DNA sequencing and subtyping analysis confirmed the presence of zoonotic C. parvum subtypes IIaA17G2R1 and IIaA16G3R1 for the first time in rodents.
Information about Plasmodium malariae is scanty worldwide due to its "benign" nature and low infection rates. Consequently, studies on the genetic polymorphisms of P. malariae are lacking. Here, we report genetic polymorphisms of 28 P. malariae circumsporozoite protein (Pmcsp) isolates from Malaysia which were compared with those in other regions in Asia as well as those from Africa. Phylogenetic analysis revealed that most Malaysian P. malariae isolates clustered together but independently from other Asian isolates. Low nucleotide diversity was observed in Pmcsp non-repeat regions in contrast to high nucleotide diversity observed in non-repeat regions of Plasmodium knowlesi CSP gene, the current major cause of malaria in Malaysia. This study contributes to the characterisation of naturally occurring polymorphisms in the P. malariae CSP gene.