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Global genetic diversity of Spirometra tapeworms

Hong X, Liu SN, Xu FF, Han LL, Jiang P, Wang ZQ, et al.

Trop Biomed, 2020 Mar 01;37(1):237-250.
PMID: 33612735

Spirometra larvae are etiological agents of human sparganosis. However, the systematics of spirometrid cestodes has long been controversial. In order to determine the current knowledge on the evolution and genetic structure of Spirometra, an exhaustive population diversity analysis of spirometrid cestodes using the mitochondrial gene: cytochrome c oxidase subunit 1 (cox1) was performed. All publicly available cox1 sequences available in the GenBank and 127 new sequencing genes from China were used as the dataset. The haplotype identify, network, genetic differentiation and phylogenetic analysis were conducted successively. A total of 488 sequences from 20 host species, representing four spirometrid tapeworms (S. decipiens, S. ranarum, S. erinaceieuropaei and Sparganum proliferum) and several unclassified American and African isolates from 113 geographical locations in 17 countries, identified 45 haplotypes. The genetic analysis revealed that there are four clades of spirometrid cestodes: Clade 1 (Brazil + USA) and Clade 2 (Argentina + Venezuela) included isolates from America, Clade 3 contained African isolates and one Korean sample, and the remainders from Asia and Australia belonged to Clade 4; unclassified Spirometra from America and Africa should be considered the separate species within the genus; and the taxonomy of two Korea isolates (S. erinaceieuropaei KJ599680 and S. decipiens KJ599679) was still ambiguous and needs to be further identified. In addition, the demographical analyses supported population expansion for the total spirometrid population. In summary, four lineages were found in the spirometrid tapeworm, and further investigation with deeper sampling is needed to elucidate the population structure.

Matched MeSH terms: DNA, Helminth/genetics
Epidemiology of rumen fluke infection in selected buffalo farms in perak, malaysia: prevalence, molecular species identification, and associated risk factors

Tookhy NA, Isa NM, Rahaman YA, Ahmad NI, Sharma RSK, Idris LH, et al.

Parasitol Res, 2024 Apr 30;123(5):199.
PMID: 38687367 DOI: 10.1007/s00436-024-08219-9

Rumen flukes cause heavy economic losses in the ruminant industry worldwide, especially in tropical and subtropical countries. This study estimated the prevalence of rumen flukes in buffaloes, identified the species diversity, and determined risk factors associated with rumen fluke prevalence in Perak, Peninsular Malaysia. A cross-sectional study was conducted, and 321 faecal samples were collected from six buffalo farms. A structured questionnaire was developed, and farmers were interviewed to obtain information regarding risk factors associated with rumen fluke infection. The faecal samples were examined using sedimentation and Flukefinder® techniques. Genomic DNA was extracted from the fluke eggs recovered using the Flukefinder® method, and the internal transcribed spacer 2 (ITS2) fragment was amplified and sequenced to facilitate species identification. The results showed that the overall prevalence of rumen fluke across the sampled farms was 40.2% (129/321). Three rumen fluke species were identified, namely, Fischoederius elongatus, F. cobboldi, and Orthocoelium streptocoelium. Several management factors had a significant association (P

Matched MeSH terms: DNA, Helminth/genetics
Fulltext Fasciolasis in Tuaran, Sabah: A Case Report

Bizini, Fionna Vincent

Borneo Journal of Medical Sciences, 2018;12(101):35-36.
MyJurnal

Fascioliasis is a major parasitic disease caused by the liver flukes, Fasciola hepatica and Fasciola gigantica in Malaysia. On 31st May 2016, three cases of fasciolasis among humans were notified in Tuaran involving two localities.

Matched MeSH terms: DNA, Helminth
Toxocara malaysiensis infection in domestic cats in Vietnam--An emerging zoonotic issue?

Le TH, Anh NT, Nguyen KT, Nguyen NT, Thuy do TT, Gasser RB

Infect Genet Evol, 2016 Jan;37:94-8.
PMID: 26584512 DOI: 10.1016/j.meegid.2015.11.009

Toxocara canis of canids is a parasitic nematode (ascaridoid) that infects humans and other hosts, causing different forms of toxocariasis. This species of Toxocara appears to be the most important cause of human disease, likely followed by Toxocara cati from felids. Although some studies from Malaysia and China have shown that cats can harbor another congener, T. malaysiensis, no information is available about this parasite for other countries. Moreover, the zoonotic potential of this parasite is unknown at this point. In the present study, we conducted the first investigation of domestic dogs and cats for Toxocara in Vietnam using molecular tools. Toxocara malaysiensis was identified as a common ascaridoid of domestic cats (in the absence of T. cati), and T. canis was commonly found in dogs. Together with findings from previous studies, the present results emphasize the need to explore the significance and zoonotic potential of T. malaysiensis in Vietnam and other countries where this parasite is endemic and prevalent in cats.

Matched MeSH terms: DNA, Helminth/analysis*
Revisiting the question of limited genetic variation within Schistosoma japonicum

Le TH, Blair D, McManus DP

Ann Trop Med Parasitol, 2002 Mar;96(2):155-64.
PMID: 12080976

Recent electrophoretic data have indicated that Schistosoma japonicum in mainland China may be a species complex, with the existence of a cryptic species being predicted from the analysis of schistosome populations from Sichuan province. To investigate the Sichuan form of S. japonicum, 4.9 kbp of mitochondrial DNA from each of three samples of the parasite from China (two from Sichuan and one from Hunan) and one from Sorsogon in the Philippines were amplified, sequenced and characterized. The sequence data were compared with those from the related South-east Asian species of S. mekongi (Khong Island, Laos) and S. mlayensis (Baling, Malaysia) and that from S. japonicm from Anhui (China). At both the nucleotide and amino-acid levels, the variation among the five S. japonicum samples was limited (< 1%). This was consistent with the conclusions drawn from previous molecular studies, in which minimal variation among S. japonicum populations was also detected. In contrast, S. mekongi and S. malayensis, species recognized as separate but closely related, differ from each other by about 10%, and each differs by 25%-26% from S. japonicum. Phylogenetic trees provided a graphic representation of these differences, showing all S. japonicum sequences to be very tightly clustered and distant from S. mekongi and S. malayensis, the last two being clearly distinct from each other. The results thus indicate no significant intra-specific genetic variation among S. japonicum samples collected from different geographical areas and do not support the idea of a distinct form in Sichuan.

Matched MeSH terms: DNA, Helminth/genetics
Mitochondrial DNA and nuclear DNA indicate that the Japanese Fasciola species is F. gigantica

Hashimoto K, Watanobe T, Liu CX, Init I, Blair D, Ohnishi S, et al.

Parasitol Res, 1997;83(3):220-5.
PMID: 9089716

For elucidation of the taxonomic status of the Japanese Fasciola species, whole mitochondrial DNA of Fasciola hepatica from Australia, F. gigantica from Malaysia, and Fasciola sp. from Japan was digested with three four-base-cutting endonucleases: HinfI, MspI, and RsaI. The resulting digestion patterns showed that for each enzyme there were some bands specific for each geographical isolate and that the Japanese Fasciola sp. shared more bands with F. gigantica than with F. hepatica. Nucleotide sequences of two regions, the second internal transcribed spacer (ITS2) of the nuclear ribosomal RNA cluster and mitochondrial cytochrome c oxidase subunit I (COI), were also compared among them. The ITS2 sequence was highly conserved among the three isolates. F. gigantica and the Japanese Fasciola sp. were identical, but they differed from the Australian F. hepatica at six sites, one of which was a deletion. The COI sequence was less conserved but implied a similar relationship between the isolates. There seems no reason to regard the Japanese Fasciola sp. as anything other than a strain of F. gigantica.

Matched MeSH terms: DNA, Helminth*
The Morphological and Molecular Description of Acanthogyrus (Acanthosentis) fusiformis n. sp. (Acanthocephala: Quadrigyridae) from the Catfish Arius sp. (Ariidae) in the Pacific Ocean off Vietnam, with Notes on Zoogeography

Amin OM, Chaudhary A, Heckmann RA, Ha NV, Singh HS

Acta Parasitol, 2019 Dec;64(4):779-796.
PMID: 31332657 DOI: 10.2478/s11686-019-00102-3

BACKGROUND: Most (82%) of the 46 recognized species of Acanthogyrus (Acanthosentis) Verma and Datta, 1929 are known from Asian freshwater fishes. Only three species of Acanthosentis are known from marine or brackish water fishes from India and Pakistan. We have discovered another marine species of Acanthosentis in the Pacific Ocean, off Vietnam.
PURPOSE: The purpose is to describe the new species morphologically and molecularly and provide new information of its evolutionally relationships with other species of the subgenus.
METHODS: Standard methods of collection and examination of marine hosts, processing and illustrating of specimens, and taxonomic identification of parasites using the extensive collection of the lead author were used. Specimens were further studied using energy-dispersive X-ray analysis and ion sectioning of hooks, SEM analysis, and molecular sequencing. Type specimens were deposited at the Harold W. Manter Lab. collection, Lincoln, Nebraska.
RESULTS: Acanthogyrus (Acanthosentis) fusiformis n. sp. is described from the catfish, Arius sp. (Ariidae: Siluriformes) off the Pacific Coast of Vietnam at Bac Lieu in the Gulf of Thailand. The three other marine Indian species include A. (A.) arii Bilqees, 1971 which is also described from a similar catfish, Arius serratus Day off the Karachi coast in the Arabian Sea, Indian Ocean. Our new species from Vietnam is distinguished from the other 46 species by a combination of characters including a small fusiform trunk, complete circles of small hollow spines covering the entire trunk, prominent double apical organs often extending posteriorly past posterior hooks, middle and posterior hooks of equal size slightly smaller than anterior hooks, large neck continuous with the outline of the proboscis without distinct separation, big drop-shaped cephalic ganglion, extension of the proboscis receptacle anteriorly past the base of the proboscis up to the insertion point of the posterior hooks, presence of two para-receptacle structures (PRSs), free unattached thick lemnisci, short female reproductive system with filamentous attachment of the distal end of the uterine bell to the ventral body wall, and small narrowly ellipsoid eggs with thickened polar ends. Partial sequences of the 18S and internal transcribed spacers (ITS1-5.8S-ITS2) of ribosomal RNA were generated and used for phylogenetic analyses to confirm the taxonomic identity of Acanthogyrus (Acanthosentis) fusiformis n. sp.
CONCLUSIONS: We describe unique morphological features of A. fusiformis never before known in the subgenus Acanthosentis. The uniqueness of A. fusiformis is further demonstrated by its EDXA fingerprint characterized by high levels of calcium and phosphorous in hooks. The zoogeography of species of Acanthosentis is elucidated in the Indian subcontinent, the Caribbean, China, and Africa. Molecular data have been available only in few species of Acanthogyrus (Acanthosentis) to date on GenBank database. For 18S, only two sequences from unknown Acanthosentis sp. from India are available, while for the ITS1-5.8S-ITS2 region, only sequences of A. cheni from China and of two unidentified species from Malaysia are available. Additional studies of species of Acanthosentis based on morphological and molecular genetic data will be needed to reconstruct the evolutionary history and phylogenetic affinities of this group of acanthocephalans.

Matched MeSH terms: DNA, Helminth/genetics
Sensitivity of the nested-polymerase chain reaction (PCR) assay for Brugia malayi and significance of 'free' DNA in PCR-based assays

Cox-Singh J, Pomrehn AS, Wolfe ND, Rahman HA, Lu HY, Singh B

Int J Parasitol, 2000 Oct;30(11):1177-9.
PMID: 11027784

The blood filtration method was used as the gold standard to determine the detection level of simple blood-spot sampling and nested-polymerase chain reaction (PCR) for Brugia malayi. Of 100 samples, 48 were filtration-positive. Of these, 26 had microfilaria counts that were low enough (<1-29 microfilariae/ml) to accurately assess the limit of detection by nested-PCR. Nested-PCR consistently detected B. malayi DNA in samples with > or = 10 microfilariae/ml. Post-filtration, microfilaria-depleted, blood-spots from microfilaria-positive samples were screened by nested-PCR and B. malayi specific 'free' DNA was detected in 51.7% of these samples. There was no evidence for 'free' DNA in microfilaria-negative individuals from this endemic community.

Matched MeSH terms: DNA, Helminth/blood*
Two microsatellite loci from Brugia malayi show polymorphisms among isolates from Indonesia and Malaysia

Underwood AP, Supali T, Wu Y, Bianco AE

Mol Biochem Parasitol, 2000 Mar 05;106(2):299-302.
PMID: 10699259
Matched MeSH terms: DNA, Helminth/genetics
Fulltext Strongyloides stercoralis in common vegetables and herbs in Kota Bharu, Kelantan, Malaysia

Zeehaida M, Zairi NZ, Rahmah N, Maimunah A, Madihah B

Trop Biomed, 2011 Apr;28(1):188-93.
PMID: 21602786

Transmission of soil-transmitted helminthes infection is by faecal oral route, and is influenced by food preference. Kelantanese love to consume ulam which are raw vegetables and herbs. Some of the herbs grow on grounds with high humidity and are abundant near drainage areas, these are also places with higher likelihood of harbouring viable parasite ova. The aim of this study was to determine the prevalence of soiltransmitted helminthes in vegetables, herbs and fruits found in our local setting. The results by microscopy showed that there was no helminthes ovum or protozoan parasite in the samples. However, Strongyloides stercoralis rhabdatiform larvae were identified in water samples used to wash pegaga, kesum and water spinach, and the number of larvae observed were 152, 9 and 16 respectively. Analysis by real-time PCR confirmed the microscopic observation of this helminth. This study highlighted that vegetables and herbs are likely sources of Strongyloides stercoralis infection in Kota Bharu, Kelantan. Thus vegetable sellers as well as the food handlers are the two important groups who are at high risk of acquiring the infection.

Matched MeSH terms: DNA, Helminth/genetics
Fulltext Comparison of conventional versus real-time PCR detection of Brugia malayi DNA from dried blood spots from school children in a low endemic area

Rahmah N, Nurulhasanah O, Norhayati S, Zulkarnain I, Norizan M

Trop Biomed, 2010 Apr;27(1):54-9.
PMID: 20562814 MyJurnal

Microscopic detection of active phase of lymphatic filariasis is indicated by the presence of microfilaria in whole blood. This method is not sensitive and requires relatively large amount of blood sample. PCR allows very sensitive detection of the parasite DNA using a smaller amount of blood; and the use of dried blood spots facilitates sample transportation. Nevertheless, limited studies have been reported on PCR using dried blood spot for detection of Brugia malayi. In this study, we investigated the effects of concentrating whole blood genomic DNA sample and the amplification methods [conventional PCR (C-PCR) and real-time PCR] on the detection of B. malayi DNA from dried blood spots from a very low endemic area in Malaysia. Both C-PCR and real-time PCR detected 2 out of 18 (11%) samples as positive from non-concentrated genomic DNA preparations. After the DNA samples were pooled and concentrated, both C-PCR and realtime PCR detected B. malayi DNA amplifications in 7 out of 18 (39%) samples. However one sample which showed faint band in C-PCR was detected as highly positive in real-time PCR. In conclusion, both C-PCR and real-time PCR using dried blood spots from a low endemic area demonstrated equal sensitivity for detection of B. malayi DNA.

Matched MeSH terms: DNA, Helminth/genetics*
Fulltext Inferring the phylogenetic position of Brugia pahangi using 18S ribosomal RNA (18S rRNA) gene sequence

Fong MY, Asha T, Azdayanti M, Yee LL, Sinnadurai S, Rohela M

Trop Biomed, 2008 Apr;25(1):87-92.
PMID: 18600209 MyJurnal

This paper presents the first reported use of 18S rRNA gene sequence to determine the phylogeny of Brugia pahangi. The 18S rRNA nucleotide sequence of a Malaysian B. pahangi isolate was obtained by PCR cloning and sequencing. The sequence was compared with 18S rRNA sequences of other nematodes, including those of some filarial nematodes. Multiple alignment and homology analysis suggest that B. pahangi is closely related to B. malayi and Wuchereria bancrofti. Phylogenetic trees constructed using Neighbour Joining, Minimum Evolution and Maximum Parsimony methods correctly grouped B. pahangi with other filarial nematodes, with closest relationship with B. malayi and W. bancrofti. The phylogeny of B. pahangi obtained in this study is in concordance with those previously reported, in which the 5S rRNA gene spacer region and cytochrome oxidase subunit I (COI) sequences were used.

Matched MeSH terms: DNA, Helminth/analysis
Fulltext Transmission potential of Wuchereria bancrofti by Culex quinquefasciatus in urban areas of Malaysia

Vythilingam I, Tan CH, Nazni WA

Trop Biomed, 2005 Jun;22(1):83-5.
PMID: 16880760 MyJurnal

Laboratory strain of the Malaysian Culex quinquefasciatus was susceptible to Wuchereria bancrofti. Thirty three percent of the Cx. quinquefasciatus that fed on W. bancrofti patient were infective after 12-14 days. There is a possibility for W. bancrofti to occur in the urban areas of the Malaysia in the near future.

Matched MeSH terms: DNA, Helminth/analysis
Molecular phylogeographic studies on Paragonimus westermani in Asia

Iwagami M, Ho LY, Su K, Lai PF, Fukushima M, Nakano M, et al.

J Helminthol, 2000 Dec;74(4):315-22.
PMID: 11138020

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.

Matched MeSH terms: DNA, Helminth/genetics
Cytochrome c oxidase subunit I haplotype reveals high genetic diversity of Angiostrongylus malaysiensis (Nematoda: Angiostrongylidae)

Eamsobhana P, Yong HS, Song SL, Prasartvit A, Boonyong S, Tungtrongchitr A

J Helminthol, 2018 Mar;92(2):254-259.
PMID: 28330511 DOI: 10.1017/S0022149X17000244

The rat lungworm Angiostrongylus malaysiensis is a metastrongyloid nematode parasite. It has been reported in Malaysia, Thailand, Laos, Myanmar, Indonesia and Japan. In this study, A. malaysiensis adult worms recovered from the lungs of wild rats in different geographical regions/provinces in Thailand were used to determine their haplotype by means of the mitochondrial partial cytochrome c oxidase subunit I (COI) gene sequence. The results revealed high COI haplotype diversity of A. malaysiensis from Thailand. The geographical isolates of A. malaysiensis from Thailand and other countries formed a monophyletic clade distinct from the closely related A. cantonensis. In the present study, five new haplotypes were identified in addition to the four haplotypes reported in the literature. Phylogenetic analysis revealed that four of these five new haplotypes - one from Mae Hong Song (northern region), two from Tak (western region) and one from Phang Nga (southern region) - formed a distinct clade with those from Phatthalung (southern region) and Malaysia. The haplotype from Malaysia was identical to that of Phatthalung (haplotype AM1). In general, the COI sequences did not differentiate unambiguously the various geographical isolates of A. malaysiensis. This study has confirmed the presence of high COI genetic diversity in various geographical isolates of A. malaysiensis. The COI gene sequence will be suitable for studying genetic diversity, population structure and phylogeography.

Matched MeSH terms: DNA, Helminth/genetics
Sympatric species distribution, genetic diversity and population structure of Haemonchus isolates from domestic ruminants in Pakistan

Hussain T, Periasamy K, Nadeem A, Babar ME, Pichler R, Diallo A

Vet Parasitol, 2014 Dec 15;206(3-4):188-99.
PMID: 25468018

Haemonchus species are major gastro-intestinal parasites affecting ruminants across the world. The present study aimed to assess the sympatric species distribution, genetic diversity, population structure and frequency of β-tubulin isotype 1 alleles associated with benzimidazole resistance. Internal transcribed spacer 2 (ITS2) sequences revealed three sympatric species of Haemonchus, H. contortus, H. placei and H. longistipes with 12 distinct genotypes circulating among ruminant hosts in Pakistan. High genetic variability was observed in Pakistani Haemonchus isolates at nicotine amide dehydrogenase subunit 4 (ND4) and cytochrome oxidase subunit 1 (COI) gene loci. Intra-population diversity parameters were higher in H. contortus isolates than H. placei. Phylogenetic analysis of ND4 and COI sequences did not reveal clustering of haplotypes originating from a particular host indicating high rate of gene flow among Haemonchus parasites infecting sheep, goat and cattle in Pakistan. ND4 and COI haplotypes from Pakistan were compared to sequences of Haemonchus isolates from 11 countries to elucidate the population structure. Multidimensional scaling (MDS) plot of pairwise FST derived from 531 ND4 haplotypes revealed clustering together of H. contortus from Pakistan, China, Malaysia and Italy while the isolates from Yemen and United States were found to be genetically distinct. With respect to H. placei, isolates from Pakistan were found to be genetically differentiated from isolates of other countries. The tests for selective neutrality revealed negative D statistics and did not reveal significant deviations in Pakistani Haemonchus populations while significant deviation (P < 0.05) was observed in Brazilian and Chinese H. contortus populations. Median Joining (MJ) network of ND4 haplotypes revealed Yemenese H. contortus being closer to H. placei cluster. β-tubulin isotype 1 genotyping revealed 7.86% frequency of Y allele associated with benzimidazole resistance at F200Y locus in Pakistani Haemonchus isolates.

Matched MeSH terms: DNA, Helminth/genetics; DNA, Helminth/chemistry
Fulltext Genetic variability within and among Haemonchus contortus isolates from goats and sheep in China

Yin F, Gasser RB, Li F, Bao M, Huang W, Zou F, et al.

Parasit Vectors, 2013 Sep 25;6(1):279.
PMID: 24499637 DOI: 10.1186/1756-3305-6-279

BACKGROUND: Haemonchus contortus (order Strongylida) is a common parasitic nematode infecting small ruminants and causing significant economic losses worldwide. Knowledge of genetic variation within and among H. contortus populations can provide a foundation for understanding transmission patterns, the spread of drug resistance alleles and might assist in the control of haemonchosis.
METHODS: 152 H. contortus individual adult worms were collected from seven different geographical regions in China. The second internal transcribed spacer (ITS-2) of the nuclear ribosomal DNA and mitochondrial nicotinamide dehydrogenase subunit 4 gene (nad4) were amplified by polymerase chain reaction (PCR) and sequenced directly. The sequence variations and population genetic diversities were determined.
RESULTS: Nucleotide sequence analyses revealed 18 genotypes (ITS-2) and 142 haplotypes (nad4) among the 152 worms, with nucleotide diversities of 2.6% and 0.027, respectively, consistent with previous reports from other countries, including Australia, Brazil, Germany, Italy, Malaysia, Sweden, the USA and Yemen. Population genetic analyses revealed that 92.4% of nucleotide variation was partitioned within populations; there was no genetic differentiation but a high gene flow among Chinese populations; some degree of genetic differentiation was inferred between some specimens from China and those from other countries.
CONCLUSIONS: This is the first study of genetic variation within H. contortus in China. The results revealed high within-population variations, low genetic differentiation and high gene flow among different populations of H. contortus in China. The present results could have implications for studying the epidemiology and ecology of H. contortus in China.

Matched MeSH terms: DNA, Helminth/genetics; DNA, Helminth/chemistry
Genetic characterization of the partial mitochondrial cytochrome oxidase c subunit I (cox 1) gene of the zoonotic parasitic nematode, Ancylostoma ceylanicum from humans, dogs and cats

Ngui R, Mahdy MA, Chua KH, Traub R, Lim YA

Acta Trop, 2013 Oct;128(1):154-7.
PMID: 23774318 DOI: 10.1016/j.actatropica.2013.06.003

Ancylostoma ceylanicum is the only zoonotic hookworm species that is able to produce patent infections in humans with the majority of cases reported in South East Asia. Over the past few years, there have been an increasing number of studies investigating the prevalence of this parasitic zoonosis using molecular diagnostic tools and a single genetic locus as marker for species identification. As there can be limitations in using a single genetic locus for epidemiological studies and genetic discrimination, the complementary use of a more variable locus will provide additional evidence to support the zoonotic exchange of hookworm species between humans and animals. In the present study, the cytochrome c oxidase subunit 1 (cox 1) sequence of A. ceylanicum from positive human and animal fecal samples were determined and compared with published reference sequences. Phylogenetic analysis demonstrated that isolates of A. ceylanicum were divided into two clusters, one consisting 3 human isolates and the other comprising 19 isolates of human and animal origin from different geographical locations within Malaysia. The two groups of A. ceylanicum could be distinguished from one another through five fixed nucleotide differences at locations 891, 966, 1008, 1077 and 1083. The detection of genetically distinct groups and considerable level of genetic variation within the cox 1 sequence of A. ceylanicum might suggest potential haplotype-linked differences in zoonotic, epidemiological and pathobiological characteristics, a hypothesis that still needs further investigation.

Matched MeSH terms: DNA, Helminth/genetics; DNA, Helminth/chemistry
Identification of a molecular marker for the Y chromosome of Brugia malayi

Underwood AP, Bianco AE

Mol Biochem Parasitol, 1999 Mar 15;99(1):1-10.
PMID: 10215019

Random amplification of polymorphic DNA (RAPD) was used to analyse genomic DNA from virgin females and males of Brugia malayi, with a view to identifying sex-specific differences predicted by an XX/XY system of chromosomal sex determination. A product of 2338 bp, amplified with the arbitrary primer 5' GTTGCGATCC 3', was obtained exclusively from males. Primers based on the sequence of this product amplified a DNA fragment of the expected size from each of two independent isolates of B. malayi (from Malaysia and Indonesia) by PCR. No reaction product was obtained from the closely related species Brugia pahangi. In a genetic cross between B. malayi males and B. pahangi females, F1 hybrid microfilariae were PCR-positive, indicating that the locus is paternally-inherited. Southern blotting demonstrated that the target sequence resides in the high molecular weight fraction of genomic DNA, confirming that it is of chromosomal, rather than mitochondrial, origin. Sequencing of the locus revealed significant similarity with members of a family of reverse transcriptase-like genes in Caenorhabditis elegans. In-frame stops indicate that the gene is non-functional, but multiple bands of hybridisation in Southern blots suggest that the RT sequence may be the relic of a transposable element. Multiple repeats of the dinucleotide AT occurred in another region of the sequence. These varied in number between the two isolates of B. malayi in the manner of a microsatellite, surprisingly the first to be described from the B. malayi genome. Because of its association with the Y chromosome, we have given the locus the acronym TOY (Tag On Y). Identification of this chromosome-specific marker confirms the XX/XY heterogametic karyotype in B. malayi and opens the way to elucidation of the role of Y in sex determination.

Matched MeSH terms: DNA, Helminth/analysis; DNA, Helminth/isolation & purification
Fulltext Enterobius vermicularis salpingitis seen in the setting of ectopic pregnancy in a Malaysian patient

Ngui R, Ravindran S, Ong DB, Chow TK, Low KP, Nureena ZS, et al.

J Clin Microbiol, 2014 Sep;52(9):3468-70.
PMID: 24989613 DOI: 10.1128/JCM.01191-14

We report a rare and unusual case of invasive Enterobius vermicularis infection in a fallopian tube. The patient was a 23-year-old Malaysian woman who presented with suprapubic pain and vaginal bleeding. A clinical diagnosis of ruptured right ovarian ectopic pregnancy was made. She underwent a laparotomy with a right salpingo-oophorectomy. Histopathological examination of the right fallopian tube showed eggs and adult remnants of E. vermicularis, and the results were confirmed using PCR and DNA sequencing.

Matched MeSH terms: DNA, Helminth/genetics; DNA, Helminth/chemistry

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