Displaying publications 41 - 60 of 131 in total

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  1. Patterns and Risk Factors of Soil-Transmitted Helminthiasis Among Orang Asli Subgroups in Peninsular Malaysia
    Ngui R, Aziz S, Chua KH, Aidil RM, Lee SC, Tan TK, et al.
    Am J Trop Med Hyg, 2015 Aug;93(2):361-70.
    PMID: 26055746 DOI: 10.4269/ajtmh.13-0677
    A cross-sectional study was conducted to provide comprehensive data on the patterns and associated risk factors of soil-transmitted helminth (STH) infections among five Orang Asli subgroups in Peninsular Malaysia. The overall prevalence of STH infections was 59.9% (95% confidence interval [CI] = 56.1-63.7%). Trichuris trichiura (54.3%; 95% CI = 50.4-58.2%) was the predominant species followed by Ascaris lumbricoides (26.7%; 95% CI = 23.3-30.1%) and hookworm (9.1%; 95% CI = 6.9-11.3%). This study showed diversity for STH infections by subgroup with poverty and personal sanitary behavior as important risk factors for infection. Risk profile analyses indicating that Orang Kuala subgroup who has a generally well-developed infrastructure and better quality of life had a low rate of infection. There is a need for poverty reduction and promotion of deworming programs along with mass scale campaigns to create awareness about health and hygiene to reduce STH infections.
  2. Fulltext Pathogenic waterborne free-living amoebae: An update from selected Southeast Asian countries
    Abdul Majid MA, Mahboob T, Mong BG, Jaturas N, Richard RL, Tian-Chye T, et al.
    PLoS One, 2017;12(2):e0169448.
    PMID: 28212409 DOI: 10.1371/journal.pone.0169448
    Data on the distribution of free-living amoebae is still lacking especially in Southeast Asian region. The aquatic environment revealed a high occurrence of free-living amoebae (FLA) due to its suitable condition and availability of food source, which subsequently causes infection to humans. A total of 94 water samples consisted of both treated and untreated from Laos (31), Myanmar (42), and Singapore (21) were investigated for the presence of pathogenic FLA. Each water sample was filtered and cultured onto non-nutrient agar seeded with live suspension of Escherichia coli and incubated at room temperature. Morphological identification was conducted for both trophozoites and cysts via microscopic stains (Giemsa and immunofluorescence). The presence of Naegleria-like structures was the most frequently encountered in both treated and untreated water samples, followed by Acanthamoeba-like and Vermamoeba-like features. To identify the pathogenic isolates, species-specific primer sets were applied for molecular identification of Acanthamoeba, Naegleria, and Vermamoeba. The pathogenic species of Acanthamoeba lenticulata and A. triangularis were detected from untreated water samples, while Vermamoeba vermiformis was found in both treated and untreated water samples. Our results suggested that poor water quality as well as inadequate maintenance and treatment might be the cause of this alarming problem since chlorine disinfection is ineffective in eradicating these amoebas in treated water samples. Regular monitoring and examination of water qualities are necessary in order to control the growth, hence, further preventing the widespread of FLA infections among the public.
  3. Parasitic infections in Malaysia: changing and challenges
    Nissapatorn V, Lim YA, Jamaiah I, Agnes LS, Amyliana K, Wen CC, et al.
    Southeast Asian J. Trop. Med. Public Health, 2005;36 Suppl 4:50-9.
    PMID: 16438180
    A total of 1,885 blood and stool samples of four main protozoan parasitic infections were retrospectively reviewed from January, 2000 to April, 2004. Eleven of the 1,350 stool samples were shown positive for Cryptosporidium and Giardia infections; one of the 5 cases was clinically diagnosed as gastrointestinal cryptosporidiosis, while 6 cases were giardiasis. In patients with giardiasis, children were among the high-risk groups, making up 66.7% of these patients. The common presenting signs and symptoms were: diarrhea (83.3%), loss of appetite (83.3%), lethargy (83.3%), fever (66.7%), nausea/vomiting (50.0%), abdominal pain (16.7%), dehydration (16.7%) and rigor and chills (16.7%). Metronidazole was the drug of choice and was given to all symptomatic patients (83.3%). For the blood samples, 28 of the 92 peripheral smears for Plasmodium spp infection were diagnosed as malaria. The age range was from 4 to 57, with a median of 32.5 years. The sex ratio (M:F) was 3.6:1, while the age group of 30-44 years was the most commonly affected in both sexes. The majority of patients were foreigners (60.7%) and non-professional (39%). Plasmodium vivax (71%) infection was the most common pathogen found in these patients, along with a history of traveling to an endemic area of malaria (31%). The predominant presenting signs and symptoms were: fever (27%), rigor and chills (24%), nausea/vomiting (15%) and headache (8%). Chloroquine and primaquine was the most common anti-malarial regimen used (78.6%) in these patients. The seroprevalence of toxoplasmosis in different groups was 258/443 (58%): seropositive for IgG 143 (32.3%); IgM 67 (15%); and IgG + IgM 48 (10.8%). The age range was from 1 to 85, with a mean of 34 (+/- SD 16.6) years. The predominant age group was 21 to 40 years (126; 28.4%). The sex ratio (M:F) was 1.2:1. Subjects were predominantly male (142; 32%) and the Malay (117; 26.4%). Of these, 32 cases were clinically diagnosed with ocular toxoplasmosis. The range of age was from 10 to 56 years with a mean of 30.5 (+/- SD 12.05) years. The sex ratio (M:F) was 1:1.7. The majority were in the age group of 21 to 40 years, female (20; 62.5%), and Malay (17; 53%). They were also single (16; 50%), unemployed (12; 37%), and resided outside Kuala Lumpur (21; 65.6%). The more common clinical presentations were blurring of vision (25; 78%), floaters (10; 31%) and pain in the eye (7; 22%). We found that funduscopic examination (100%) and seropositivity for anti-Toxoplasma antibodies (93.7%) were the main reasons for investigation. Choroidoretinitis was the most common clinical diagnosis (69%), while clindamycin was the most frequently used antimicrobial in all cases. Among HIV-infected patients, 10 cases were diagnosed as AIDS-related toxoplasmic encephalitis (TE) (9 were active and 1 had relapse TE). In addition, 1 case was confirmed as congenital toxoplasmosis.
  4. Over two decades of Plasmodium knowlesi infections in Sarawak: Trend and forecast
    Ooi CH, Bujang MA, Tg Abu Bakar Sidik TMI, Ngui R, Lim YA
    Acta Trop, 2017 Dec;176:83-90.
    PMID: 28768148 DOI: 10.1016/j.actatropica.2017.07.027
    Malaria is still of great public health concern, especially in Malaysian Borneo. The aim of this study was to determine the trends of P. knowlesi infection in Sarawak, Malaysia and to forecast the incidence of P. knowlesi until the year 2040. Data on P. knowlesi malaria cases from 1992 to the year 2014 were obtained from the Sarawak Health Department, Malaysia. ARIMA model was applied to forecast the future incidence of P. knowlesi infection. The data for the whole of Sarawak and subsequently the selected six districts which have high incidence rates of P. knowlesi infection were analyzed. Results of the analysis showed that there was an increasing trend of P. knowlesi cases from the year 1992-2014 (p<0.001). The trend in the incidence started to increase in the year 2008 (p=0.029). The incidence rate per 100,000 populations was between 4.15 in the year 1992 and 42.03 in the year 2014. High incidence of P. knowlesi infections has been detected in the districts adjacent to each other within the interior region of Sarawak. The forecasted incidence and incidence rate per 100,000 populations in the year 2020 were 1229 and 44.04, respectively, while those in the year 2040 were 2056 and 62.91, respectively. The forecasted incidence showed an upward trend highlighting an urgent need to draw up strategic and holistic prevention plans to limit further the increase in P. knowlesi morbidity and mortality in Sarawak. It is imperative that these measures are customized taking into consideration the challenges faced in the interior areas of Sarawak and the behavior of the main vector of P. knowlesi (i.e., An. latens) in Sarawak.
  5. Occurrence of Giardia cysts and Cryptosporidium oocysts in the Temuan Orang Asli (aborigine) River System
    Lim YA, Aahmad RA
    Southeast Asian J. Trop. Med. Public Health, 2004 Dec;35(4):801-10.
    PMID: 15916072
    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.
  6. Occurrence of Cryptosporidium oocysts in Wrinkled Hornbill and other birds in the Kuala Lumpur National Zoo
    Rohela M, Lim YA, Jamaiah I, Khadijah PY, Laang ST, Nazri MH, et al.
    Southeast Asian J. Trop. Med. Public Health, 2005;36 Suppl 4:34-40.
    PMID: 16438177
    The occurrence of a coccidian parasite, Cryptosporidium, among birds in the Kuala Lumpur National Zoo was investigated in this study. A hundred bird fecal samples were taken from various locations of the zoo. Fecal smears prepared using direct smear and formalin ethyl acetate concentration technique were stained with modified Ziehl-Neelsen stain. Samples positive for Cryptosporidium with Ziehl-Neelsen stain were later confirmed using the immunofluorescence technique and viewed under the epifluorescence microscope. Six species of bird feces were confirmed positive with Cryptosporidium oocysts. They included Wrinkled Hornbill (Aceros corrugatus), Great Argus Pheasant (Argusianus argus), Black Swan (Cygnus atratus), Swan Goose (Anser cygnoides), Marabou Stork (Leptoptilos crumeniferus), and Moluccan Cockatoo (Cacatua moluccencis). These birds were located in the aviary and lake, with the Moluccan Cockatoo routinely used as a show bird. Results obtained in this study indicated that animal sanctuaries like zoos and bird parks are important sources of Cryptosporidium infection to humans, especially children and other animals.
  7. Fulltext Nutritional status, hemoglobin level and their associations with soil-transmitted helminth infections between Negritos (indigenous) from the inland jungle village and resettlement at town peripheries
    Muslim A, Lim YA, Mohd Sofian S, Shaari SA, Mohd Zain Z
    PLoS One, 2021;16(1):e0245377.
    PMID: 33439889 DOI: 10.1371/journal.pone.0245377
    This study compared the current nutritional status, hemoglobin levels and their associations with soil-transmitted helminth (STH) infections between two categories of Negritos (indigenous): (i) Inland Jungle Villages (IJV) (ii) and Resettlement Plan Scheme (RPS) near town peripheries, decades after redevelopment and demarginalization. A total of 416 Negritos (IJV: 149; RPS: 267) was included for nutritional profiling based on anthropometric analysis. However, only 196 (IJV: 64; RPS: 132) individuals consented to blood taking for the hemoglobin (Hb) measurements. Subsequently, the association of undernutrition and anemia with STH infections were determined based on univariate and multivariate logistic regression analyses. The overall prevalence of stunting, wasting, and underweight amongst children and adolescents (n = 343) were 45.8%, 42.3% and 59.1%, respectively. In adults (n = 73), the prevalence of underweight was low (6.8%) but overweight and obese was prominent (26.0%). For anemia (n = 196), an overall prevalence rate of 68.4% were observed with 80% and 70.4% of children aged 2-6 y/o and aged 7-12 y/o, respectively being anemic. Comparatively, the prevalence of underweight (WAZ) was significantly higher in the RPS versus the IJV (P = 0.03) In the IJV, children aged ≤ 6 y/o and having STH poly-parasitism were associated with underweight (P = 0.01) and moderate-severe T. trichiura infection was associated with anemia. Whilst in the RPS, underweight was highly associated with only T. trichiura infection (P = 0.04). Wasting was significantly associated with young children aged ≤10 in both IJV (P = 0.004) and RPS (P = 0.02). Despite efforts in improving provision of facilities and amenities among the indigenous, this study highlighted a high magnitude of nutritional issues among the Negritos especially those in the RPS and their likely association with STH infections and decades of demarginalization. Joint nutritional intervention strategies with mass anti-helminthic treatment are imperative and urgently needed to reduce the undernutrition problems especially among indigenous children.
  8. Fulltext New insights into the genetic diversity of Schistosoma mansoni and S. haematobiumin Yemen
    Sady H, Al-Mekhlafi HM, Webster BL, Ngui R, Atroosh WM, Al-Delaimy AK, et al.
    Parasit Vectors, 2015;8:544.
    PMID: 26482435 DOI: 10.1186/s13071-015-1168-8
    Human schistosomiasis is a neglected tropical disease of great importance that remains highly prevalent in Yemen, especially amongst rural communities. In order to investigate the genetic diversity of human Schistosoma species, a DNA barcoding study was conducted on S. mansoni and S. haematobium in Yemen.
  9. Fulltext Neglected tropical diseases among two indigenous subtribes in peninsular Malaysia: highlighting differences and co-infection of helminthiasis and sarcocystosis
    Lee SC, Ngui R, Tan TK, Muhammad Aidil R, Lim YA
    PLoS One, 2014;9(9):e107980.
    PMID: 25248116 DOI: 10.1371/journal.pone.0107980
    Soil-transmitted helminth (STH) infections have been documented among these minority groups since 1938. However the prevalence of STH is still high among these communities. Most studies tend to consider the Orang Asli (indigenous) as a homogenous group. In contrary, different subtribes have their own cultural practices. To understand this variation better, we studied the prevalence and associated factors of STH and other gut parasitic infections among two common subtribes (i.e. Temuan and Temiar). Results showed that the prevalence of the overall STH infections was higher in the Temuan subtribe (53.2% of 171) compared to the Temiar subtribe (52.7% of 98). Trichuris trichiura (46.2%) was the most prevalent parasite in the Temuan subtribe, followed by Ascaris spp. (25.7%) and hookworm (4.1%). In contrast, Ascaris spp. (39.8%) was more prevalent among the Temiar subtribe, preceded by T. trichiura (35.7%) and finally hookworm (8.3%). There were also co-infections of helminthiasis and intestinal protozoa among both Temuan and Temiar subtribes with rates being three times higher among the Temiar compared to Temuan. The most common co-infection was with Entamoeba histolytica/dispar/moshkovskii (n = 24; 24.5%, 16.0-33.0), followed by Giardia spp. (n = 3; 3.1%, -0.3-6.5). In Temuan, STH infection individuals were also infected with Entamoeba histolytica/dispar/moshkovskii (n = 11; 6.4%, 5.0-13.8), Cryptosporidium spp. (n = 3, 1.8%, -0.2-3.8) and Giardia spp. (n = 2, 1.2%, -0.4-2.8). In comparison, there was no Cryptosporidium spp. detected among the Temiar. However, it was interesting to note that there was an occurrence of co-infection of intestinal helminthiasis and sarcocystosis (intestinal) in a Temiar individual. The last report of sarcocystosis (muscular) among the Orang Asli was in 1978. The present study highlighted the importance of understanding the variation of infections amongst the different Orang Asli subtribes. It is vital to note these differences and use this knowledge to customise effective control measures for the various subtribes.
  10. Fulltext Neglected tropical diseases among the Association of Southeast Asian Nations (ASEAN): overview and update
    Hotez PJ, Bottazzi ME, Strych U, Chang LY, Lim YA, Goodenow MM, et al.
    PLoS Negl Trop Dis, 2015 Apr;9(4):e0003575.
    PMID: 25880767 DOI: 10.1371/journal.pntd.0003575
    The ten member states of the Association of Southeast Asian Nations (ASEAN) constitute an economic powerhouse, yet these countries also harbor a mostly hidden burden of poverty and neglected tropical diseases (NTDs). Almost 200 million people live in extreme poverty in ASEAN countries, mostly in the low or lower middle-income countries of Indonesia, the Philippines, Myanmar, Viet Nam, and Cambodia, and many of them are affected by at least one NTD. However, NTDs are prevalent even among upper middle-income ASEAN countries such as Malaysia and Thailand, especially among the indigenous populations. The three major intestinal helminth infections are the most common NTDs; each helminthiasis is associated with approximately 100 million infections in the region. In addition, more than 10 million people suffer from either liver or intestinal fluke infections, as well as schistosomiasis and lymphatic filariasis (LF). Intestinal protozoan infections are widespread, while leishmaniasis has emerged in Thailand, and zoonotic malaria (Plasmodium knowlesi infection) causes severe morbidity in Malaysia. Melioidosis has emerged as an important bacterial NTD, as have selected rickettsial infections, and leptospirosis. Leprosy, yaws, and trachoma are still endemic in focal areas. Almost 70 million cases of dengue fever occur annually in ASEAN countries, such that this arboviral infection is now one of the most common and economically important NTDs in the region. A number of other arboviral and zoonotic viral infections have also emerged, including Japanese encephalitis; tick-borne viral infections; Nipah virus, a zoonosis present in fruit bats; and enterovirus 71 infection. There are urgent needs to expand surveillance activities in ASEAN countries, as well as to ensure mass drug administration is provided to populations at risk for intestinal helminth and fluke infections, LF, trachoma, and yaws. An ASEAN Network for Drugs, Diagnostics, Vaccines, and Traditional Medicines Innovation provides a policy framework for the development of new control and elimination tools. Together with prominent research institutions and universities, the World Health Organization (WHO), and its regional offices, these organizations could implement important public health improvements through NTD control and elimination in the coming decade.
  11. Fulltext Neglected Intestinal Parasites, Malnutrition and Associated Key Factors: A Population Based Cross-Sectional Study among Indigenous Communities in Sarawak, Malaysia
    Rajoo Y, Ambu S, Lim YA, Rajoo K, Tey SC, Lu CW, et al.
    PLoS One, 2017;12(1):e0170174.
    PMID: 28095446 DOI: 10.1371/journal.pone.0170174
    Intestinal parasitic infections (IPIs) have been recognized as one of the most significant causes of illness among disadvantaged communities. Many studies have been conducted on the prevalence of IPIs in Malaysia. However, these studies mostly focused on the indigenous groups in Peninsular Malaysia. The present study was conducted to provide the current baseline data on prevalence of IPIs, anaemia, malnutrition and associated risk factors among the indigenous communities in Sarawak, situation at northwest Borneo island of Malaysia. A cross sectional study was conducted among the longhouses communities. Stool samples were obtained and examined for the presence of IPIs using microscopy technique. Haemoglobin measurement was done using a portable haemoglobin analyzer. Malnutrition (i.e., stunting, underweight and wasting) was assessed using the WHO Anthro software. Statistical analysis was carried out using SPSS software. A total of 341participants took part in this study. The overall prevalence of IPIs was 57.5%. Multivariate analysis indicated that the absence of toilets (OR = 1.6; 95% CI = 1.1-2.7; p = 0.002) and close contact with animals (OR = 1.8; 95% CI = 1.3-2.9; p = 0.027) as significant predictors for IPIs. The incidence of anaemia was 36.4%. The incidence of underweight, wasting and stunting were 22.2%, 5.6% and 35.4%, respectively. Multivariate analysis demonstrated that low level of parental education attainment (OR = 1.9; 95% CI = 1.2-3.0; p = 0.006) was identified as significant predictor for anaemia. The incidence of wasting was significantly associated with mild anaemia (OR = 1.2; 95% CI = 0.9-1.7; p = 0.024). Low household income was identified as significant predictor for stunting (OR = 2.1; 95% CI = 9.8-22.2; p = 0.001) and underweight (OR = 1.9; 95% CI = 5.6-18.7; p = 0.037), respectively. Essentially, the present study highlighted that intestinal parasitic infections, anaemia and malnutrition are still prevalent among rural indigenous community in Sarawak. Improvement of socioeconomic status, periodic mass deworming, iron supplementation and health education program should be included in the control and prevention of public health strategies.
  12. Fulltext Natural Human Infections with Plasmodium cynomolgi, P. inui, and 4 other Simian Malaria Parasites, Malaysia
    Yap NJ, Hossain H, Nada-Raja T, Ngui R, Muslim A, Hoh BP, et al.
    Emerg Infect Dis, 2021 08;27(8):2187-2191.
    PMID: 34287122 DOI: 10.3201/eid2708.204502
    We detected the simian malaria parasites Plasmodium knowlesi, P. cynomolgi, P. inui, P. coatneyi, P. inui-like, and P. simiovale among forest fringe-living indigenous communities from various locations in Malaysia. Our findings underscore the importance of using molecular tools to identify newly emergent malaria parasites in humans.
  13. Multilocus genotyping of Giardia duodenalis in Malaysia
    Huey CS, Mahdy MA, Al-Mekhlafi HM, Nasr NA, Lim YA, Mahmud R, et al.
    Infect Genet Evol, 2013 Jul;17:269-76.
    PMID: 23624189 DOI: 10.1016/j.meegid.2013.04.013
    Giardia duodenalis is considered the most common intestinal parasite in humans worldwide. In Malaysia, many studies have been conducted on the epidemiology of giardiasis. However, there is a scarcity of information on the genetic diversity and the dynamics of transmission of G. duodenalis. The present study was conducted to identify G. duodenalis assemblages and sub-assemblages based on multilocus analysis of the glutamate dehydrogenase (gdh), beta-giardin (bg) and triose phosphate isomerase (tpi) genes. Faecal specimens were collected from 484 Orang Asli children with a mean age of 7 years and examined using light microscopy. Specimens positive for Giardia were subjected to PCR analysis of the three genes and subsequent sequencing in both directions. Sequences were edited and analysed by phylogenetic analysis. G. duodenalis was detected in 17% (84 of 484) of the examined specimens. Among them, 71 were successfully sequenced using at least one locus. Genotyping results showed that 30 (42%) of the isolates belonged to assemblage A, 32 (45%) belonged to assemblage B, while discordant genotype results were observed in 9 specimens. Mixed infections were detected in 43 specimens using a tpi-based assemblage specific protocol. At the sub-assemblages level, isolates belonged to assemblage A were AII. High nucleotide variation found in isolates of assemblage B made subtyping difficult to achieve. The finding of assemblage B and the anthroponotic genotype AII implicates human-to-human transmission as the most possible mode of transmission among Malaysian aborigines. The high polymorphism found in isolates of assemblage B warrants a more defining tool to discriminate assemblage B at the sub-assemblage level.
  14. Mosquito Biology and Mosquito-Borne Disease Awareness Among Island Communities In Malaysia
    Shafie A, Roslan MA, Ngui R, Lim YA, Sulaiman WY
    J Am Mosq Control Assoc, 2016 Dec;32(4):273-281.
    PMID: 28206867 DOI: 10.2987/16-6604.1
    Mosquito-borne diseases have been increasing at an alarming rate over the past decades. In Malaysia, one finds several important mosquito-borne diseases such as Japanese encephalitis, dengue, malaria, and chikungunya. Mosquito surveillance and control programs are the most effective way of detecting and controlling mosquito-borne diseases, but these programs are less effective without an aware and well-informed general public. In 2014 we used a questionnaire to evaluate the extent of awareness of basic mosquito biology and mosquito-borne diseases in 6 villages, Kampung Masjid, Kampung Teluk Gedung, Kampung Teluk Dalam, Kampung Ujung Kelawai, Kampung Sungai Pinang Besar, and Kampung Sungai Pinang Kechil on Pangkor Island, Malaysia. A total of 1,012 individuals responded to the questionnaire, consisting of 790 Malay (78.1%), 164 Chinese (16.2%), and 58 Indian (5.7%). More than 60% (Malay = 73.7%, Chinese = 64.0%, Indian = 79.3%) of the respondents were familiar with basic mosquito biology and practiced personal protection against mosquito bites, and the association was statistically significant (P = 0.02). However, the majority of the respondents had limited knowledge on mosquito-borne diseases, and this varied significantly among the 3 ethnic groups (P = 0.0001). Our recommendations are to improve and intensify public health education outreach programs to the island residents and to encourage community participation in vector control programs.
  15. Fulltext Morphological and molecular characteristics of Malayfilaria sofiani Uni, Mat Udin & Takaoka n. g., n. sp. (Nematoda: Filarioidea) from the common treeshrew Tupaia glis Diard & Duvaucel (Mammalia: Scandentia) in Peninsular Malaysia
    Uni S, Mat Udin AS, Agatsuma T, Saijuntha W, Junker K, Ramli R, et al.
    Parasit Vectors, 2017 Apr 20;10(1):194.
    PMID: 28427478 DOI: 10.1186/s13071-017-2105-9
    BACKGROUND: The filarial nematodes Wuchereria bancrofti (Cobbold, 1877), Brugia malayi (Brug, 1927) and B. timori Partono, Purnomo, Dennis, Atmosoedjono, Oemijati & Cross, 1977 cause lymphatic diseases in humans in the tropics, while B. pahangi (Buckley & Edeson, 1956) infects carnivores and causes zoonotic diseases in humans in Malaysia. Wuchereria bancrofti, W. kalimantani Palmieri, Pulnomo, Dennis & Marwoto, 1980 and six out of ten Brugia spp. have been described from Australia, Southeast Asia, Sri Lanka and India. However, the origin and evolution of the species in the Wuchereria-Brugia clade remain unclear. While investigating the diversity of filarial parasites in Malaysia, we discovered an undescribed species in the common treeshrew Tupaia glis Diard & Duvaucel (Mammalia: Scandentia).

    METHODS: We examined 81 common treeshrews from 14 areas in nine states and the Federal Territory of Peninsular Malaysia for filarial parasites. Once any filariae that were found had been isolated, we examined their morphological characteristics and determined the partial sequences of their mitochondrial cytochrome c oxidase subunit 1 (cox1) and 12S rRNA genes. Polymerase chain reaction (PCR) products of the internal transcribed spacer 1 (ITS1) region were then cloned into the pGEM-T vector, and the recombinant plasmids were used as templates for sequencing.

    RESULTS: Malayfilaria sofiani Uni, Mat Udin & Takaoka, n. g., n. sp. is described based on the morphological characteristics of adults and microfilariae found in common treeshrews from Jeram Pasu, Kelantan, Malaysia. The Kimura 2-parameter distance between the cox1 gene sequences of the new species and W. bancrofti was 11.8%. Based on the three gene sequences, the new species forms a monophyletic clade with W. bancrofti and Brugia spp. The adult parasites were found in tissues surrounding the lymph nodes of the neck of common treeshrews.

    CONCLUSIONS: The newly described species appears most closely related to Wuchereria spp. and Brugia spp., but differs from these in several morphological characteristics. Molecular analyses based on the cox1 and 12S rRNA genes and the ITS1 region indicated that this species differs from both W. bancrofti and Brugia spp. at the genus level. We thus propose a new genus, Malayfilaria, along with the new species M. sofiani.

  16. Fulltext Monitoring of Waterborne Parasites in Two Drinking Water Treatment Plants: A Study in Sarawak, Malaysia
    Richard RL, Ithoi I, Abd Majid MA, Wan Sulaiman WY, Tan TC, Nissapatorn V, et al.
    Int J Environ Res Public Health, 2016 06 28;13(7).
    PMID: 27367710 DOI: 10.3390/ijerph13070641
    The occurrence of waterborne parasites coupled with water parameters at various processing sites of two drinking water treatment plants (A and B) and seven distribution system (DS) sites in Sarawak, Malaysia were studied. Ten liters of water underwent immunomagnetic separation (IMS) technique to detect the presence of Giardia and Cryptosporidium (oo)cysts. The remaining supernatant was used to detect other parasites whilst 50 mL of water sample was each used in the detection of free-living amoebae and fecal coliforms. Sampled water was positive for Giardia (32.9%; 28/85), Cryptosporidium (18.8%; 16/85) followed by Spirometra ova-like (25.9%; 22/85), Blastocystis-like (25.9%; 22/85), nematode larvae-like (8.2%; 7/85) and Taenia ova-like (1.2%; 1/85). Meanwhile, 90.2% (55/61) samples were positive for Acanthamoeba and Naegleria via cultivation and of these, 11 isolates were confirmed as Acanthamoeba genotype T3 (5/7) and T4 (2/7) followed by Naegleria sp. (4/11), Naegleria italica (2/11), Naegleria australiensis (1/11), Naegleria angularis (1/11) and Vahlkampfia sp. (3/11). Cryptosporidium, Acanthamoeba and Naegleria were also detected in one of the seven tested DS sites. Only Giardia and Cryptosporidium showed significant correlations with fluoride and fecal coliforms. These results describe the occurrence of waterborne parasites that will assist key stakeholders in mitigating contamination at the specific sites.
  17. Fulltext Molecular identification of human hookworm infections in economically disadvantaged communities in Peninsular Malaysia
    Ngui R, Ching LS, Kai TT, Roslan MA, Lim YA
    Am J Trop Med Hyg, 2012 May;86(5):837-42.
    PMID: 22556084 DOI: 10.4269/ajtmh.2012.11-0446
    Species identification of human hookworm infections among eight communities in rural areas of Peninsular Malaysia was determined during 2009-2011. Fecal samples were examined by microscopy and subsequently, the internal transcribed spacer 2 and 28S ribosomal RNA region of Necator americanus and Ancylostoma spp. were sequenced. Overall, 9.1% (58 of 634) were identified positive by microscopy for hookworm infection, and 47 (81.0%) of 58 were successfully amplified and sequenced. Sequence comparison found that N. americanus (87.2%) was the most predominant hookworm identified, followed by Ancylostoma ceylanicum (23.4%). No A. duodenale infection was detected in this study. Detection of A. ceylanicum in humans highlighted the zoonotic transmission among humans living near dogs. Thus, implementation of effective control measures for hookworm infections in future should seriously consider this zoonotic implication.
  18. Molecular identification of Cryptosporidium parvum from avian hosts
    Quah JX, Ambu S, Lim YA, Mahdy MA, Mak JW
    Parasitology, 2011 Apr;138(5):573-7.
    PMID: 21232175 DOI: 10.1017/S0031182010001691
    Cryptosporidium species are protozoan parasites that infect humans and a wide variety of animals. This study was aimed at identifying Cryptosporidium species and genotypes isolated from avian hosts. A total of 90 samples from 37 different species of birds were collected throughout a 3-month period from April 2008 to June 2008 in the National Zoo of Kuala Lumpur, Malaysia. Prior to molecular characterization, all samples were screened for Cryptosporidium using a modified Ziehl-Neelsen staining technique. Subsequently samples were analysed with nested-PCR targeting the partial SSU rRNA gene. Amplicons were sequenced in both directions and used for phylogenetic analysis using Neighbour-Joining and Maximum Parsimony methods. Although 9 (10%) samples were positive for Cryptosporidium via microscopy, 8 (8.9%) produced amplicons using nested PCR. Phylogenetic trees identified all the isolates as Cryptosporidium parvum. Although C. parvum has not been reported to cause infection in birds, and the role of birds in this study was postulated mainly as mechanical transporters, these present findings highlight the significant public health risk posed by birds that harbour the zoonotic species of Cryptosporidium.
  19. Molecular detection of Giardia contamination in water bodies in a zoo
    Lim YA, Lai MM, Mahdy MA, Mat Naim HR, Smith HV
    Environ Res, 2009 Oct;109(7):857-9.
    PMID: 19664767 DOI: 10.1016/j.envres.2009.07.007
    We used a combined microscopy-molecular approach to determine the occurrence and identities of waterborne Giardia sp. cysts isolated from 18 separate, 10l grab samples collected from a Malaysian zoo. Microscopy revealed that 17 of 18 samples were Giardia cyst positive with concentrations ranging from 1 to 120 cysts/l. Nine (52.9%) of the 17 cyst positive samples produced amplicons of which 7 (77.8%) could be sequenced. Giardia duodenalis assemblage A (6 of 7) and assemblage B (1 of 7), both infectious to humans, were identified at all sampling sites at the zoo. The presence of human infectious cysts raises public health issues, and their occurrence, abundance and sources should be investigated further. In this zoo setting, our data highlight the importance of incorporating environmental sampling (monitoring) in addition to routine faecal examinations to determine veterinary and public health risks, and water monitoring should be considered for inclusion as a separate element in hazard analysis, as it often has a historical (accumulative) connotation.
  20. Fulltext Molecular characterization of Leishmania species isolated from cutaneous leishmaniasis in Yemen
    Mahdy MA, Al-Mekhlafi HM, Al-Mekhlafi AM, Lim YA, Bin Shuaib NO, Azazy AA, et al.
    PLoS One, 2010 Sep 20;5(9).
    PMID: 20862227 DOI: 10.1371/journal.pone.0012879
    BACKGROUND: Cutaneous leishmaniasis (CL) is a neglected tropical disease endemic in the tropics and subtropics with a global yearly incidence of 1.5 million. Although CL is the most common form of leishmaniasis, which is responsible for 60% of DALYs lost due to tropical-cluster diseases prevalent in Yemen, available information is very limited.

    METHODOLOGY/PRINCIPAL FINDINGS: This study was conducted to determine the molecular characterization of Leishmania species isolated from human cutaneous lesions in Yemen. Dermal scrapes were collected and examined for Leishmania amastigotes using the Giemsa staining technique. Amplification of the ribosomal internal transcribed spacer 1(ITS-1) gene was carried out using nested PCR and subsequent sequencing. The sequences from Leishmania isolates were subjected to phylogenetic analysis using the neighbor-joining and maximum parsimony methods. The trees identified Leishmania tropica from 16 isolates which were represented by two sequence types.

    CONCLUSIONS/SIGNIFICANCE: The predominance of the anthroponotic species (i.e. L. tropica) indicates the probability of anthroponotic transmission of cutaneous leishmaniasis in Yemen. These findings will help public health authorities to build an effective control strategy taking into consideration person-to-person transmission as the main dynamic of transmission of CL.

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