Displaying publications 101 - 120 of 180 in total

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  1. Dawaki S, Al-Mekhlafi HM, Ithoi I
    Trans R Soc Trop Med Hyg, 2019 04 01;113(4):169-182.
    PMID: 30551211 DOI: 10.1093/trstmh/try128
    BACKGROUND: Parasitic infections constitute a major public health problem worldwide, particularly among underprivileged communities in developing countries including Nigeria. The present study aimed to determine the epidemiology of polyparasitism (multiple parasitic infections) among rural communities in Kano State, North Central Nigeria.

    METHODS: A total of 551 individuals were screened for the presence of intestinal, urogenital and blood parasites by using different diagnostic techniques. Demographic, socioeconomic, household and behavioural characteristics were collected using a pre-tested questionnaire.

    RESULTS: Overall, 84.0% (463/551) of the participants were found to be infected with at least one parasite species, with 51.2% (282/551) of them having polyparasitism. The most prevalent parasites were Plasmodium falciparum (60.6%) followed by Blastocystis sp. (29.2%) and hookworm (15.4%). No significant association was found between malaria and helminth infections (p>0.05). Univariate and multivariate analyses showed that the presence of other family members who had intestinal polyparasitism (adjusted odds ratio [AOR]=4.12; 95% CI=2.72, 6.24), walking barefoot outside (AOR=1.70; 95% CI=1.09, 2.63) and being male (AOR=1.74; 95% CI=1.14, 2.66) were the significant risk factors of intestinal polyparasitism among the population studied.

    CONCLUSION: Polyparasitism is highly prevalent among rural communities in Kano State. Therefore, effective, sustainable and integrated control measures should be identified and implemented to significantly reduce the burden and consequences of these infections in rural Nigeria.

  2. Sam IC, Montoya M, Chua CL, Chan YF, Pastor A, Harris E
    Trans R Soc Trop Med Hyg, 2019 11 01;113(11):678-684.
    PMID: 31294807 DOI: 10.1093/trstmh/trz056
    BACKGROUND: Zika virus (ZIKV) is believed to be endemic in Southeast Asia. However, there have been few Zika cases reported to date in Malaysia, which could be due to high pre-existing levels of population immunity.

    METHODS: To determine Zika virus (ZIKV) seroprevalence in Kuala Lumpur, Malaysia, 1085 serum samples from 2012, 2014-2015 and 2017 were screened for anti-ZIKV antibodies using a ZIKV NS1 blockade-of-binding assay. Reactive samples were confirmed using neutralization assays against ZIKV and the four dengue virus (DENV) serotypes. A sample was possible ZIKV seropositive with a ZIKV 50% neutralization (NT50) titre ≥20. A sample was probable ZIKV seropositive if, in addition, all DENV NT50 titres were <20 or the ZIKV NT50 titre was >4-fold greater than the highest DENV NT50 titre.

    RESULTS: We found low rates of possible ZIKV seropositivity (3.3% [95% confidence interval {CI} 2.4 to 4.6]) and probable ZIKV seropositivity (0.6% [95% CI 0.3 to 1.4]). Possible ZIKV seropositivity was independently associated with increasing age (odds ratio [OR] 1.04 [95% CI 1.02 to 1.06], p<0.0001) and male gender (OR 3.5 [95% CI 1.5 to 8.6], p=0.005).

    CONCLUSIONS: The low ZIKV seroprevalence rate, a proxy for population immunity, does not explain the low incidence of Zika in dengue-hyperendemic Kuala Lumpur. Other factors, such as the possible protective effects of pre-existing flavivirus antibodies or reduced transmission by local mosquito vectors, should be explored. Kuala Lumpur is at high risk of a large-scale Zika epidemic.

  3. Barker RA, Maxwell PH, Hong CP, Cordery MC, Chrystie IL
    Trans R Soc Trop Med Hyg, 1988;82(6):898-901.
    PMID: 2855768
    Over a period of 2 months, 35 of 69 (51%) cases of juvenile diarrhoea studied in eastern Malaysia were associated with rotavirus excretion; rotavirus associated diarrhoea occurred most commonly in the 6-24 month age group. Polyacrylamide gel electrophoresis (PAGE) of genome ribonucleic acid showed that only 4 rotavirus electropherotypes could be detected. Of those, 2 predominated and 2 were detected only once each; one of these may have been a reassortment of the two predominant electropherotypes. Analysis of the clinical features of patients excreting rotavirus subgroup 1 or 2, determined by PAGE, demonstrated that rotavirus subgroup 1 was associated with more hypotonic dehydration and need for intravenous therapy: lethargy was significantly more common among those excreting rotavirus subgroup 2.
  4. Zakaria ND, Avoi R
    PMID: 34453834 DOI: 10.1093/trstmh/trab132
    BACKGROUND: Lymphatic filariasis (LF) is a public health problem in Sabah, Malaysia. In the subdistrict of Tangkarason, nine rounds of mass drug administration (MDA) were probably not effective in reducing the prevalence of microfilaria to the <1% threshold recommended by the World Health Organization for stopping MDA. This cross-sectional study was conducted to identify the risk factors associated with positive LF antibody in Tangkarason.

    METHODS: Eligible adults >18 y of age in seven endemic villages in Tangkarason, Beluran, Sabah, were interviewed and tested for LF antibody using the Brugia Rapid kit. Multivariable logistic regression was employed to analyse the associated factors.

    RESULTS: A total of 244 respondents were included in this study. Their median age was 40 y (interquartile range 30-53). The antibody prevalence of brugian filariasis in the study population was 31.1% (95% confidence interval [CI] 25.7 to 37.2). Older age (adjusted odds ratio [aOR] 1.04 [95% CI 1.02 to 1.06]) and outdoor jobs (aOR 2.26 [95% CI 1.05 to 4.85]) were identified as independent risk factors for positive LF antibody. Participating in the MDA program previously (aOR 0.24 [95% CI 0.10 to 0.57]) was found to be a protective factor for LF infection.

    CONCLUSIONS: A high prevalence of microfilariae was confirmed in all the study sites, which was above the target of <1%. Important factors associated with positive LF antibody were identified, which could be used as a guide for program managers to design more focused control measures in LF-endemic areas.

  5. Tan CH, Palasuberniam P, Blanco FB, Tan KY
    Trans R Soc Trop Med Hyg, 2021 01 07;115(1):78-84.
    PMID: 32945886 DOI: 10.1093/trstmh/traa087
    BACKGROUND: The Philippine cobra (Naja philippinensis) and Samar cobra (Naja samarensis) are two WHO Category 1 medically important venomous snakes in the Philippines. Philippine cobra antivenom (PCAV) is the only antivenom available in the country, but its neutralization capacity against the venoms of N. philippinensis and hetero-specific N. samarensis has not been reported. This knowledge gap greatly hinders the optimization of antivenom use in the region.

    METHODS: This study examined the immunological binding and neutralization capacity of PCAV against the two cobra venoms using WHO-recommended protocols.

    RESULTS: In mice, both venoms were highly neurotoxic and lethal with a median lethal dose of 0.18 and 0.20 µg/g, respectively. PCAV exhibited strong and comparable immunoreactivity toward the venoms, indicating conserved venom antigenicity between the two allopatric species. In in vivo assay, PCAV was only moderately effective in neutralizing the toxicity of both venoms. Its potency was even lower against the hetero-specific N. samarensis venom by approximately two-fold compared with its potency against N. philippinensis venom.

    CONCLUSION: The results indicated that PCAV could be used to treat N. samarensis envenomation but at a higher dose, which might increase the risk of hypersensitivity and worsen the shortage of antivenom supply in the field. Antivenom manufacturing should be improved by developing a low-dose, high-efficacy product against cobra envenomation.

  6. Alharazi TH, Al-Mekhlafi HM
    Trans R Soc Trop Med Hyg, 2021 06 02;115(6):687-698.
    PMID: 33130880 DOI: 10.1093/trstmh/traa115
    BACKGROUND: This cross-sectional survey aimed to assess the knowledge, attitudes and practices (KAP) towards schistosomiasis among rural schoolchildren in Taiz governorate, southwestern Yemen.

    METHODS: A total of 406 children were screened for urogenital and intestinal schistosomiasis. A pretested questionnaire was used to collect the children's demographic and socio-economic information and their KAP towards schistosomiasis.

    RESULTS: Overall, 73 children (18%) were found to be infected by Schistosoma mansoni. None of the children were positive for Schistosoma haematobium. The prevalence of intestinal schistosomiasis was significantly higher among boys than girls (22.1% vs 12%; p=0.010). Approximately two-thirds (63.3% [257/406]) of the children had heard about schistosomiasis, however, only 38.5%, 53.6%, 28.4% and 38.1% had correct knowledge concerning the causes, symptoms, transmission and prevention, respectively. A significantly higher level of knowledge was observed among boys and Schistosoma-infected children compared with girls and non-infected children (p<0.05). However, a better level of knowledge does not seem to translate directly into the performance of hygienic practices. Multivariate logistic regression showed that sex and infection status were the significant predictors of good knowledge.

    CONCLUSIONS: Intestinal schistosomiasis is prevalent among schoolchildren in rural Yemen. The findings reveal that children's knowledge about schistosomiasis is inadequate. Therefore, besides mass drug administration, integrated control programmes should also include health education and the provision of improved drinking water and proper sanitation.

  7. Azami NAM, Moi ML, Salleh SA, Neoh HM, Kamaruddin MA, Jalal NA, et al.
    Trans R Soc Trop Med Hyg, 2020 11 06;114(11):798-811.
    PMID: 32735681 DOI: 10.1093/trstmh/traa056
    BACKGROUND: A periodic serosurvey of dengue seroprevalence is vital to determine the prevalence of dengue in countries where this disease is endemic. This study aimed to determine the prevalence of dengue immunoglobulin G (IgG) seropositivity among healthy Malaysian adults living in urban and rural areas.

    METHODS: A total of 2598 serum samples (1417 urban samples, 1181 rural samples) were randomly collected from adults ages 35-74 y. The presence of the dengue IgG antibody and neutralising antibodies to dengue virus (DENV) 1-4 was determined using enzyme-linked immunosorbent assay and the plaque reduction neutralisation test assay, respectively.

    RESULTS: The prevalence of dengue IgG seropositivity was 85.39% in urban areas and 83.48% in rural areas. The seropositivity increased with every 10-y increase in age. Ethnicity was associated with dengue seropositivity in urban areas but not in rural areas. The factors associated with dengue seropositivity were sex and working outdoors. In dengue IgG-positive serum samples, 98.39% of the samples had neutralising antibodies against DENV3, but only 70.97% of them had neutralising antibodies against DENV4.

    CONCLUSION: The high seroprevalence of dengue found in urban and rural areas suggests that both urban and rural communities are vital for establishing and sustaining DENV transmission in Malaysia.

  8. Souza AA, Ducker C, Argaw D, King JD, Solomon AW, Biamonte MA, et al.
    Trans R Soc Trop Med Hyg, 2021 01 28;115(2):129-135.
    PMID: 33169166 DOI: 10.1093/trstmh/traa118
    Accurate and reliable diagnostic tools are an essential requirement for neglected tropical diseases (NTDs) programmes. However, the NTD community has historically underinvested in the development and improvement of diagnostic tools, potentially undermining the successes achieved over the last 2 decades. Recognizing this, the WHO, in its newly released draft roadmap for NTD 2021-2030, has identified diagnostics as one of four priority areas requiring concerted action to reach the 2030 targets. As a result, WHO established a Diagnostics Technical Advisory Group (DTAG) to serve as the collaborative mechanism to drive progress in this area. Here, the purpose and role of the DTAG are described in the context of the challenges facing NTD programmes.
  9. Dass S, Ngui R, Gill BS, Chan YF, Wan Sulaiman WY, Lim YAL, et al.
    Trans R Soc Trop Med Hyg, 2021 08 02;115(8):922-931.
    PMID: 33783526 DOI: 10.1093/trstmh/trab053
    BACKGROUND: We studied the spatiotemporal spread of a chikungunya virus (CHIKV) outbreak in Sarawak state, Malaysia, during 2009-2010.

    METHODS: The residential addresses of 3054 notified CHIKV cases in 2009-2010 were georeferenced onto a base map of Sarawak with spatial data of rivers and roads using R software. The spatiotemporal spread was determined and clusters were detected using the space-time scan statistic with SaTScan.

    RESULTS: Overall CHIKV incidence was 127 per 100 000 population (range, 0-1125 within districts). The average speed of spread was 70.1 km/wk, with a peak of 228 cases/wk and the basic reproduction number (R0) was 3.1. The highest age-specific incidence rate was 228 per 100 000 in adults aged 50-54 y. Significantly more cases (79.4%) lived in rural areas compared with the general population (46.2%, p<0.0001). Five CHIKV clusters were detected. Likely spread was mostly by road, but a fifth of rural cases were spread by river travel.

    CONCLUSIONS: CHIKV initially spread quickly in rural areas mainly via roads, with lesser involvement of urban areas. Delayed spread occurred via river networks to more isolated areas in the rural interior. Understanding the patterns and timings of arboviral outbreak spread may allow targeted vector control measures at key transport hubs or in large transport vehicles.

  10. Laghari M, Talpur BA, Sulaiman SAS, Khan AH, Bhatti Z
    Trans R Soc Trop Med Hyg, 2021 08 02;115(8):904-913.
    PMID: 33382889 DOI: 10.1093/trstmh/traa161
    BACKGROUND: Information on the extent of patient medication adherence and the use of interventions to advance adherence are scarce in clinical practice. This study aimed to assess medication adherence and risk factors for non-adherence among the caregivers of children with tuberculosis (TB).

    METHODS: This prospective study was conducted among the caregivers of 443 child TB patients registered during the study. Caregivers of children were queried using a structured questionnaire consisting of sociodemographic and socio-economic factors and the role of healthcare workers during the treatment course. Risk factors for non-adherence were estimated using a logistic regression model.

    RESULTS: In multivariate analysis, the independent variables that had a statistically significant positive association with non-adherence were male sex (adjusted odds ratio [AOR] 5.870 [95% confidence interval {CI} 1.99 to 17.29]), age ≥45 y (AOR 5.627 [95% CI 1.88 to 16.82]), caregivers with no formal education (AOR 3.905 [95% CI 1.29 to 11.79]), financial barriers (AOR 30.297 [95% CI 6.13 to 149.54]), insufficient counselling by healthcare workers (AOR 5.319 [95% CI 1.62 to 17.42]), insufficient counselling by health professionals (AOR 4.117 [95% CI 1.05 to 16.05]) and unfriendly attitude and poor support from healthcare professionals (AOR 11.150 [95% CI 1.91 to 65.10]).

    CONCLUSIONS: Treatment adherence in the present study was 86% using the Morisky Green Levine Medication Adherence Scale and 90.7% using the visual analogue scale tool. Predictors of non-adherence need to be a focus and caregivers should be given complete knowledge about the importance of adherence to TB treatment.

  11. Zulkipli MS, Rampal S, Bulgiba A, Peramalah D, Jamil N, See LLC, et al.
    Trans R Soc Trop Med Hyg, 2021 07 01;115(7):764-771.
    PMID: 33587144 DOI: 10.1093/trstmh/trab021
    BACKGROUND: Dengue, an acute infectious disease caused by a flavivirus, is a threat to global health. There is sparse evidence exploring obesity and the development of more severe dengue cases in adults. With increasing prevalence of obesity in areas with a high risk of dengue infection, obesity may increase the burden and mortality related to dengue infection. Our study aimed to determine the association between obesity and the development of more severe dengue infection in primary healthcare settings and whether these associations were modified by dengue fever phase.

    METHODS: A cohort study was conducted among laboratory-confirmed dengue patients aged >18 y in the central region of Peninsular Malaysia from May 2016 to November 2017. We collected demographic, clinical history, physical examination and laboratory examination information using a standardized form. Dengue severity (DS) was defined as either dengue with warning signs or severe dengue. Participants underwent daily follow-up, during which we recorded their vital signs, warning signs and full blood count results. Incidence of DS was modeled using mixed-effects logistic regression. Changes in platelet count and hematocrit were modeled using mixed-effects linear regression. The final multivariable models were adjusted for age, gender, ethnicity and previous dengue infection.

    RESULTS: A total of 173 patients were enrolled and followed up. The mean body mass index (BMI) was 37.4±13.75 kg/m2. The majority of patients were Malay (65.9%), followed by Chinese (17.3%), Indian (12.7%) and other ethnic groups (4.1%). A total of 90 patients (52.0%) were male while 36 patients (20.8%) had a previous history of dengue infection. BMI was significantly associated with DS (adjusted OR=1.17; 95% CI 1.04 to 1.34) and hematocrit (%) (aβ=0.09; 95% CI 0.01 to 0.16), but not with platelet count (x103/µL) (aβ=-0.01; 95% CI -0.84 to 0.81). In the dose response analysis, we found that as BMI increases, the odds of DS, hematocrit levels and platelet levels increase during the first phase of dengue fever.

    CONCLUSION: Higher BMI and higher hematocrit levels were associated with higher odds of DS. Among those with high BMI, the development of DS was observed during phase one of dengue fever instead of during phase two. These novel results could be used by clinicians to help them risk-stratify dengue patients for closer monitoring and subsequent prevention of severe dengue complications.

  12. Naing C, Mak JW, Aung K, Wong JY
    Trans R Soc Trop Med Hyg, 2013 Feb;107(2):65-73.
    PMID: 23222952 DOI: 10.1093/trstmh/trs019
    The present review aimed to synthesise available evidence on the efficacy of dihydroartemisinin-piperaquine (DP) in treating uncomplicated Plasmodium falciparum malaria in people living in malaria-endemic countries by performing a meta-analysis of relevant studies. We searched relevant studies in electronic data bases up to December 2011. Published results from randomised controlled trials (RCTs) comparing efficacy of DP with other artemisinin-based combination therapies (ACTs), or non-ACTs, or placebo were selected. The primary endpoint was 28-day and 42-day treatment failure. We identified 26 RCTs. Many of the studies included in the present review were of high quality. Overall, DP, artesunate-mefloquine (MAS3) and artemether-lumefentrine (AL) were equally effective for reducing the risk of recurrent parasitaemia. The PCR confirmed efficacy of DP (99.5%) and MAS3 (97.7%) at day 28 exceeded 90%; both are efficacious. Comparable efficacy was also found for DP (95.6%) and AL (94.3%). The present review has documented that DP is comparable to other currently used ACTs such as MAS3 and AL in treating uncomplicated falciparum malaria. The better safety profile of DP and once-daily dosage improves adherence and its fixed co-formulation ensures that both drugs are taken together. Our conclusion is that DP has the potential to become a first-line antimalarial drug.
  13. Saunders JP, Brown GW, Shirai A, Huxsoll DL
    Trans R Soc Trop Med Hyg, 1980;74(2):253-7.
    PMID: 6770503
    Serological surveillance for up to two years of 114 patients with laboratory confirmed scrub typhus showed that antibody to Rickettsia tsutsugamushi as demonstrated by the indirect fluorescent antibody test is short-lived. The mean reversion time from mean peak titre (1:499) was 48.9 weeks and the calculated annual reversion rate to a titre less than 1:50 was 61%. This can be used to estimate attack rates based on point prevalence of antibody. The relationship between antibody prevalence and attack rates observed by other workers was confirmed using this model. The possible uses of the finding and its implications in Malaysia are briefly discussed.
  14. Thomas V, Bin HK, Leng YP
    Trans R Soc Trop Med Hyg, 1980;74(3):375-80.
    PMID: 7001690
    In 1973, 2610 sera were collected from adults living in 22 localities in four states in Peninsular Malaysia and tested by IFAT for Plasmodium falciparum antibodies. A larger number of thin films were examined. The attack phase of the Malaria Eradication Programme (MEP) in these areas was started between 1968 and 1973. The results showed that the highest prevalence rates and geometrical mean reciprocal titres (CMRT) were among adults from Kelantan where the antibody prevalence varied greatly among the adults and there was active transmission in at least three areas. The values were lowest for Kedah. The P. falciparum antibody prevalence rates were higher than the parasite rates as revealed in single thin film examinations but a number of the positive sera were reactive only at low titres. The low concentration probably indicated the residual antibody from cured cases or past infections and cross reactions to P. vivax and P. malariae infections. The strong reactions probably indicated current P. falciparum transmission as shown by positive thin films. The present study showed that the antibody profile of adults, as shown by IFAT, is of considerable value in assessing the malaria situation in a given area and that it would be useful as a malariometric tool in epidemiological studies to evaluate the progress of malaria eradication/control programmes.
  15. Kwa BH, Mak JW
    Trans R Soc Trop Med Hyg, 1980;74(4):522-7.
    PMID: 7445050
    The possible depression of cell-mediated immunity by long-term Brugia malayi infection in jirds (Meriones unguiculatus) was investigated. Different groups of infected jirds were sensitized with dinitrofluorobenzene, sheep red blood cells, Dirofilaria immitis adult antigens and B. malayi adult antigens. The 24-hour delayed type hypersensitivity skin response to testing with antigen was measured as an in vivo correlate of cell-mediated immunity. The delayed-type hypersensitivity responses to dinitrofluorobenzene, sheep red blood cells and D. immitis antigens were normal but the response to B. malayi antigens was significantly depressed, confirming that long-term B. malayi infection depresses cell-mediated immunity and that this depression is specific to B. malayi antigens.
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