Serological evidence of exposure and possible Taenia solium larval infection in Orang Asli communities of Peninsular Malaysia

Orang Asli communities are known as aborigines of peninsular Malaysia who are underprivileged and also known to be carriers of many different parasitic infections. However, the possible burden of cysticercosis (caused by Taenia solium larvae or Cysticercus cellulosae) has never been explored in these communities. Objective of this study was to explore the seroprevalence of human cysticercosis among Orang Asli (subgroups: Semelai, Semai Pahang, Temuan, Orang Kuala, Temiar, Semai Perak, and Mah Meri) communities. In this preliminary study, both male and female of all age groups (1 to 68 years) were screened for T. solium larvae specific antibodies in sera employing a commercially procured IgG-ELISA kit. Sera from a total of 522 randomly chosen Orang Asli individuals were screened between July to December 2013. A total of 20 (3.8%) subjects were diagnosed positive for anti-Cysticercus antibodies (95% CI: 2.5% – 5.8%; χ2=17.8; p<0.05). The prevalence of antibody positivity ranged between 0.9% (Semelai subgroup) to 9.9% (Orang Kuala subgroup). Statistical significance was observed between the low income status of family and seropositivity for cysticercosis (p=0.041) based on univariate analysis. Present study findings indicated that exposure to T. solium larval infection might have occurred in the aborigine communities from peninsular Malaysia. Results could only suggest that cysticercosis is an under recognized health problem here. Therefore a regional public health surveillance program might help verifying further the risk factors of T. solium cysticercosis targeting a larger population in both peninsular and East Malaysia

Seroprevalence of toxocariasis among Orang Asli (Indigenous people) in Malaysia using two immunoassays

Toxocariasis is a zoonotic helminthic infection of humans caused by the dog roundworm (Toxocara canis) or cat roundworm (Toxocara cati). There are two main human syndromes: visceral larva migrans (VLM), which are characterized by symptoms associated with major organs and ocular larva migrans (OLM), in which pathological effects on the host are restricted to the eye and the optic nerve. The present study evaluated the seroprevalence of toxocariasis among the Orang Asli with an IgG4-ELISA using recombinant antigens (rTES-26, rTES-30 and rTES-120) and an IgG-ELISA commercial kit (Cypress Diagnostic, Belgium). A total of 188 serum samples were analyzed using IgG4-ELISA recombinant antigens while 83 were tested using IgG-ELISA. Overall, 9 out of 188 (4.8) samples were positive with the former assay: rTES-26 (2.7) and rTES-30 (2.1); and 63 out of 83 (75.9) were positive with the IgG-ELISA. In general, the seroprevalence of toxocariasis among males (9.5) was higher compared to females (1). Children below 12 years (6.3) have higher seroprevalence rate compared to adults (1.2). Out of 59 IgG positive samples, 56 (94.9) were also positive with soil-transmitted helminth (STH) infections which may indicate high false positivity. None of the IgG4-ELISA positive samples were positive with STH infections. Of 9 positive samples with IgG4-ELISA, 7 were also positive with IgG-ELISA giving the probability of true cases. The present finding indicated that exposure to Toxocara infection is not unusual among Malaysian aborigines, and it affects both sexes and all age groups. As a prevention strategy, more effective public health programmes to promote better understanding on the consequences of toxocariasis among the Orang Asli communities are deemed necessary

Epidemiological and genetic data supporting the transmission of ancylostoma ceylanicum among human and domestic animals

Background: Currently, information on species-specific hookworm infection is unavailable in Malaysia and is restricted worldwide due to limited application of molecular diagnostic tools. Given the importance of accurate identification of hookworms, this study was conducted as part of an ongoing molecular epidemiological investigation aimed at providing the first documented data on species-specific hookworm infection, associated risk factors and the role of domestic animals as reservoirs for hookworm infections in endemic communities of Malaysia. Methods/Findings: A total of 634 human and 105 domestic canine and feline fecal samples were randomly collected. The overall prevalence of hookworm in humans and animals determined via microscopy was 9.1 (95 CI = 7.0-11.7) and 61.9 (95 CI = 51.2-71.2), respectively. Multivariate analysis indicated that participants without the provision of proper latrine systems (OR = 3.5; 95 CI = 1.53-8.00; p = 0.003), walking barefooted (OR = 5.6; 95 CI = 2.91-10.73; p < 0.001) and in close contact with pets or livestock (OR = 2.9; 95 CI = 1.19-7.15; p = 0.009) were more likely to be infected with hookworms. Molecular analysis revealed that while most hookworm-positive individuals were infected with Necator americanus, Ancylostoma ceylanicum constituted 12.8 of single infections and 10.6 mixed infections with N. americanus. As for cats and dogs, 52.0 were positive for A. ceylanicum, 46.0 for Ancylostoma caninum and 2.0 for Ancylostoma braziliense and all were single infections. This present study provided evidence based on the combination of epidemiological, conventional diagnostic and molecular tools that A. ceylanicum infection is common and that its transmission dynamic in endemic areas in Malaysia is heightened by the close contact of human and domestic animal (i.e., dogs and cats) populations

Epidemiological study of human intestinal parasites in Sarawak, East Malaysia: A review

Intestinal parasitic infections are endemic in rural settings and may account for asymptomatic infections to various health complications. These infections are a cause of concern for communities of lower economic status, especially in developing countries. In Sarawak, indigenous populations residing in geographically inaccessible areas are socially and economically disadvantaged. Through close association with nature, these populations are prone to intestinal parasitism. Currently, scattered information has led to a continual state of neglect at each level of parasitic infection control. This urges for a review of their distribution and transmission based on previous reports to understand the pattern of the diseases in the state which can further address the improvement of mass controlling programs. A literature search was conducted to collect previous reports on human intestinal parasites in Sarawak, East Malaysia from PubMed (Medline), SCOPUS, ScienceDirect and Web of Science from January 2019 to March 2021. Extrapolating the current data in Sarawak which is still considered limited, further interdisciplinary strategies are demanded to give insights in the epidemiology and true prevalence of intestinal parasites in Sarawak. This review addresses for redirection of attitude towards intestinal parasitic infections where it should be given with ample attention by rural populations. In tandem to that, improvement of rural livelihood such as standard of living and sanitation in Sarawak should be accredited as part of the efforts to reduce the number of intestinal parasitic infections in the state. As a control measure, mass deworming should be reconsidered especially to the rural populations

Toxoplasmosis in HIV and non HIV prisoners in Malaysia

This is the first Malaysian study to determine the trend and risk factors of Toxoplasma gondii infection in HIV and non-HIV among prisoners in terms of socio-demographic and behavioural characteristics, clinical presentations and haematological distributions. Blood samples from 303 participants, comprising 133 HIV positive and 170 HIV negative inmates were collected in EDTA and plain tubes. Two mls of each blood sample in plain tubes were centrifuged at 1500 rpm for 10 minutes and the sera obtained were subjected to ELISA for detection of Toxoplasma IgM and IgG antibody towards Toxoplasma antigen. Seropositive samples for Toxoplasma IgM or both Toxoplasma IgM and IgG were further tested with Novalisa Toxoplasma gondii IgG avidity test to rule out acute from latent infections. Blood in EDTA tubes were sent to Clinical Diagnostic Lab (CDL), University Malaya Medical Centre (UMMC), Kuala Lumpur for complete blood count and differential count analysis. Overall seroprevalence of anti-T. gondii antibodies was detected in 41.9% (127 out of 303) of the participants. Anti-T. gondii antibodies was detected in 63.2% (84 out of 133) of HIV positive subjects and in 25.3% (43 out of 170) of HIV negative subjects. Seroprevalence of anti-T. gondii antibodies was significantly higher in HIV positive than in HIV negative subjects (OR = 5.06; 95% CI = 3.09-8.30; p < 0.001). The rate of T. gondii seropositivity increased significantly in those aged 40 years and above, HIV positive individuals and those with history of drug abuse. White blood cells (WBCs), neutrophils and basophils counts decreased significantly in those infected with Toxoplasma. Creating awareness about T. gondii infection and follow-up of their status is recommended. Moreover, screening of T. gondii infection in HIV-infected individuals should be considered for better treatment and management, including control and prevention

Oral bacteria detection among children with cancer in a tertiary teaching hospital in Kuala Lumpur, Malaysia

This study sought to determine the prevalence of pathogenic and non-pathogenic bacteria in the oral cavities of children with cancer. There were 68 paediatric patients with cancer who were included in this study. Oral swab samples from the dorsum of tongues and mouth floors of these patients were subjected to culture, staining, and molecular methods to detect the bacteria. The overall prevalence of gram-positive and gram-negative bacteria was 79.4% (54/68; 95% CI = 68.4 – 87.3) and 25% (17/68; 95% CI = 16.2 – 36.4), respectively. Streptococcus salivarius and Streptococcus parasanguinis were the predominant pathogenic grampositive bacteria, while Neisseria subflava and Neisseria perflava were the most common pathogenic gram-negative bacteria. The results revealed that the number of bacteria isolates recovered in patients receiving cancer treatment was higher (55.9%) than those who had not received treatment (16.2%). Therefore, more isolated pathogenic bacteria were observed post-therapy (54.4%). Pathogenic organisms can have significant implications on patient health. Awareness of the types of bacteria inhabiting the oral cavity is essential to predict and prevent dental problems, and their associated systemic complications. Findings on the diversity of oral microflora can also provide a better understanding of the aetiology of oral diseases in paediatric patients receiving cancer treatment

A conventional multiplex PCR for the detection of four common soil-transmitted nematodes in human feces : development and validation

Soil-transmitted helminth (STH) infections, mainly caused by Ascaris lumbricoides, Trichuris trichiura, and hookworms, are among the most common intestinal parasites that infect humans. The infections are widely distributed throughout tropical and subtropical countries, including Malaysia, particularly in underprivileged communities. Microscopic and culture techniques have been used as a gold standard for diagnostic techniques. However, these methods yield low sensitivity and specificity, laborious and time-consuming. Therefore, simple, rapid, and accurate alternative methods are needed for the simultaneous detection of STH infections. Although advanced technologies such as real-time multiplex PCR have been established, the use of this technique as a routine diagnostic is limited due to the high cost of the instrument. Therefore, a single-round multiplex conventional PCR assay for rapid detection of four STH species in the fecal sample was developed in this study. To perform the single-round multiplex PCR, each pair of species-specific primers was selected from target genes, including Ancylostoma duodenale (Internal Transcribed Spacer 2; accession No. AJ001594; 156 base pair), Necator americanus (ITS 2; accession No. AJ001599; 225 base pair), Ascaris lumbricoides (Internal Transcribed Spacer 1; accession No. AJ000895; 334 base pair) and Trichuris triciura (partial ITS 1, 5.8s rRNA and partial ITS 2; accession No. AM992981; 518 base pair). The results showed that the newly designed primers could detect the DNA of STH at low concentrations (0.001 ng/μl) with no cross-amplification with other species. This assay enables the differentiation of single infections as well as mixed infections. It could be used as an alternative and is a convenient method for the detection of STHs, especially for the differentiation of N. americanus and A. duodenale

Occurrence of gastro-intestinal parasites among small ruminants in Malaysia : highlighting Dicrocoelium infection in goats

The aim of the present study was to determine the gastro-intestinal (GI) parasitic infections among small ruminants (i.e., goats, sheep, deer) in Malaysia through formalin-ether concentration technique. Overall, 70.9% or 302 out of 426 small ruminants (79.4% or 251/316 goats; 87.5% or 35/40 sheep; 22.9% or 16/70 deer) were infected with at least one species of GI parasites. Overall, ten types of GI parasites [Helminth: strongyle (57.7%), Moniezia spp. (5.4%), Paramphistomum spp. (4.5%), Strongyloides spp. (4.2%), Dicrocoelium spp. (2.3%), Trichuris spp. (2.3%); Protozoa: Eimeria spp. (23.7%), Entamoeba spp. (18.8%), Giardia spp. (1.9%), Cryptosporidium spp. (0.2%)] were detected in this study. Among the studied animals, goats harboured the highest diversity of GI parasites (ten types), followed by sheep (six types) and deer (two types). Polyparasitism was observed in goats (43.7% or 138 of 316) and sheep (15.0% or 6 of 40). Cumulatively, a total of 32 combinations of coinfections (Helminth+Helminth: 8 combinations; Helminth+Protozoa: 20 combinations; Protozoa+Protozoa: 4 combinations) between detected parasites with up to quintuple infections were reported. Among these parasites, “strongyle + Eimeria spp.” and “Moniezia spp. + strongyle” were the commonest infections in goats (13.5% or 34 of 251) and sheep (5.7% or 2 of 6), respectively. This study is a comprehensive documentation on multiple GI parasitisms among small ruminant in Malaysia, and the findings are crucial for effective farm management, especially for the formulation of parasitic control and elimination strategies

Occurrence of Giardia cysts and cryptosporidium oocysts in the Temuan Orang Asli (aborigine) River System

A survey of the river water frequently used by the Temuan Orang Asli (aborigine) indicated that 66.7 of the river water samples were Giardia cyst positive and 5.6 were Cryptosporidium oocyst positive. Although Giardia cysts were detected in samples from all the sites (e.g. upstream, midstream, and downstream), Cryptosporidium was only present in one river water sample taken from downstream from a village. The only sample of upstream water which contained Giardia cysts had a concentration of 0.7 cysts/l. All samples taken from midstream contained cysts with a mean concentration of 9.8 +/- 6.6 cysts/l (range = 1-20 cysts/l). Eighty-three point three percent of the samples collected from downstream contained cysts and 16.7 had oocysts. The average concentration of cysts was 12.9 +/- 16.4 cysts/l (range = 0-44 cysts/l), whereas the oocyst concentration was 0.4 oocysts/l. All river samples tested positive for the presence of E. coli, indicating fecal contamination. The results of this study imply that the river system is contaminated with fecal-oral transmitted parasites. The river water, used by the Orang Asli, is a probable route for Giardia and Cryptosporidium transmission in this community. Long term strategies, incorporating health education regarding personal hygiene, and provision of toilets and the importance of their proper usage, need to be embraced by this community in order to control the spread of these parasites

Frequencies distribution of dihydrofolate reductase and dihydropteroate synthetase mutant alleles associated with sulfadoxine-pyrimethamine resistance in Plasmodium falciparum population from Hadhramout Governorate, Yemen

Background: Malaria in Yemen is mainly caused by Plasmodium falciparum and 25 % of the population is at high risk. Sulfadoxine-pyrimethamine (SP) had been used as monotherapy against P. falciparum. Emergence of chloroquine resistance led to the shift in anti-malarial treatment policy in Yemen to artemisinin-based combination therapy, that is artesunate (AS) plus SP as first-line therapy for uncomplicated malaria and artemether-lumefantrine as second-line treatment. This study aimed to screen mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes associated with SP resistance among P. falciparum population in Hadhramout governorate, Yemen. Methods: Genomic DNA was extracted from dried blood spots of 137 P. falciparum isolates collected from a community-based study. DNA was amplified using nested polymerase chain reaction (PCR) and subsequently sequenced for Pfdhfr and Pfdhps genes. Sequences were analysed for mutations in Pfdhfr gene codons 51, 59, 108, and 164 and in Pfdhps gene codons 436, 437, and 540. Results: A total of 128 and 114 P. falciparum isolates were successfully sequenced for Pfdhfr and Pfdhps genes, respectively. Each Pfdhfr mutant allele (I-51 and N-108) in P. falciparum population had a frequency of 84 %. Pfdhfr R-59 mutant allele was detected in one isolate. Mutation at codon 437 (G(437)) in the Pfdhps gene was detected in 44.7 % of falciparum malaria isolates. Frequencies of Pfdhfr double mutant genotype ((I) under bar C-51(59)(N) under bar I-108(164)) and Pfdhfr/Pfdhps triple mutant genotype ((I) under bar C-51(59)(N) under bar I-108(164)-S-436(G) under bar K-437(540)) were 82.8 and 39.3 %, respectively. One isolate harboured Pfdhfr triple mutant genotype ((I) under bar (51),(R) under bar (59),(N) under bar (108),I-164) and Pfdhfr/Pfdhps quadruple mutant genotype ((I) under bar (51)(R) under bar (59)(N) under bar I-108(164)-S-436(G) under bar K-437(540)). Conclusion: High frequencies of Pfdhfr and Pfdhps mutant alleles and genotypes in P. falciparum population in Hadhramout, Yemen, highlight the risk of developing resistance for SP, the partner drug of AS, which subsequently will expose the parasite to AS monotherapy increasing then the potential of the emergence of AS resistance. Study findings necessitate the continuous monitoring of the efficacy of the national anti-malarial drugs policy in Yemen. In addition, monitoring SP efficacy using molecular markers that has shown to be a practical and informative method for monitoring the partner drug of AS