MyMedR

Hereditary ovalocytosis and reduced susceptibility to malaria in Papua New Guinea

Cattani JA, Gibson FD, Alpers MP, Crane GG

Trans R Soc Trop Med Hyg, 1987;81(5):705-9.

Ovalocytosis, an hereditary condition in which most erythrocytes are oval in shape, is a polymorphism that occurs in up to 20% or more of the population in Papua New Guinea and Malaysia. Due to the geographical correlation of the trait with endemic malaria, the possibility of a selective advantage in resistance to malaria has been raised. In a study of 202 individuals with greater than or equal to 50% oval red cells matched by age, sex and village of residence with controls having less than or equal to 30% oval cells, ovalocytic subjects had blood films negative for Plasmodium vivax (P = 0.009), for P. falciparum (P = 0.044), and for all species of malaria parasites (P = 0.013), more often than controls. Among individuals parasitaemic at any time there were no clear differences in density of parasitaemia. However, in children 2 to 4 years old, parasite densities of both species were lower in ovalocytic subjects than in controls (0.01 less than P less than 0.025). The differential susceptibility to malaria infection suggested by this study has implications for the evaluation of interventions, including possible future vaccine field trials, in populations where high-frequency ovalocytosis is present.

Aggregation and predisposition to Ascaris lumbricoides and Trichuris trichiura at the familial level

Chan L, Bundy DA, Kan SP

Trans R Soc Trop Med Hyg, 1994 1 1;88(1):46-8.

PMID: 8153999 DOI: 10.1016/0035-9203(94)90492-8

This study examines the persistence of familial aggregation and familial predisposition to Ascaris lumbricoides and Trichuris trichiura infection over 2 periods of treatment and reinfection, in an urban community in Kuala Lumpur, Malaysia. Both parasite species were shown to be aggregated (assessed by the variance to mean ratio) within families at all 3 interventions, although no consistent trend in aggregation was observed over the period of the study. Associations between mean A. lumbricoides and T. trichiura infection levels of families, at all 3 interventions, were highly significant (P < 0.0001), suggesting persistent predisposition at the family level.

Infections of Blastocystis hominis and microsporidia in cancer patients: are they opportunistic?

Chandramathi S, Suresh K, Anita ZB, Kuppusamy UR

Trans R Soc Trop Med Hyg, 2012 Apr;106(4):267-9.

PMID: 22340948 DOI: 10.1016/j.trstmh.2011.12.008

Chemotherapy can cause immunosuppression, which may trigger latent intestinal parasitic infections in stools to emerge. This study investigated whether intestinal parasites can emerge as opportunistic infections in breast and colorectal cancer patients (n=46 and n=15, respectively) undergoing chemotherapy treatment. Breast cancer patients were receiving a 5-fluorouracil/epirubicin/cyclophosphamide (FEC) regimen (6 chemotherapy cycles), and colorectal cancer patients were receiving either an oxaliplatin/5-fluorouracil/folinic acid (FOLFOX) regimen (12 cycles) or a 5-fluorouracil/folinic acid (Mayo) regimen (6 cycles). Patients had Blastocystis hominis and microsporidia infections that were only present during the intermediate chemotherapy cycles. Thus, cancer patients undergoing chemotherapy should be screened repeatedly for intestinal parasites, namely B. hominis and microsporidia, as they may reduce the efficacy of chemotherapy treatments.

Changes in abundance and behaviour of vector mosquitoes induced by land use during the development of an oil palm plantation in Sarawak

Chang MS, Hii J, Buttner P, Mansoor F

Trans R Soc Trop Med Hyg, 1997 7 1;91(4):382-6.

PMID: 9373626

Surveys were conducted of adult and immature mosquitoes in an area undergoing oil palm development in north Sarawak. Point prevalence data from 2 sites were collected annually, coinciding with annual phases of forest clearing, burning/cultivation, and maintenance. Major habitat perturbation during the forest/clearing transition shifted the major mosquito faunal equilibrium in terms of species composition, relative density and occurrence. Analyses of variance showed that the mean numbers of 4 species of Anopheles decreased significantly after forest clearing. Relative densities of immature stages decreased after forest clearing, but A. letifer and Culex tritaeniorhynchus remained relatively unchanged after the second year. Comparisons with the pre-development forest stage showed that the reductions in person-biting rates, adult survival and combined entomological inoculation rates (EIR) of A. donaldi and A. letifer decreased the risk of malaria transmission by 90% over the 4 years period. Concomitant reductions in EIR and annual malaria incidence were also correlated. This study highlighted the 'law of unintended consequences', since 2 contrasting effects were observed: reduction of malaria vectors but concomitant increase of dengue vectors.

A small scale field trial with expanded polystyrene beads for mosquito control in septic tanks

Chang MS, Lian S, Jute N

Trans R Soc Trop Med Hyg, 1995 3 1;89(2):140-1.

PMID: 7778135

A field trial of the use of expanded polystyrene beads (EPSB) to control the breeding of mosquito larvae in household septic tanks was conducted in Sarawak. One week after treatment, the breeding of Culex quinquefasciatus and Aedes albopictus was reduced by 100% and 68.7% respectively. For both species combined, a 57.25% reduction in the adult emergence rate was achieved. No adult was caught in the emergence trap one month after treatment. A reduction in mosquito biting rates was reported by 87.3% of respondents. All households regarded the EPSB treatment as effective. This study has reduced the relatively high infestation rate of A. albopictus in the septic tanks to 16-20%. The EPSB treatment is feasible and practical. Post-treatment assessment using adult emergence traps and the implications for the vector control programme of the local authority are discussed.

Profile distribution of juvenile Aedes species in an urban area of Malaysia

Che Dom N, Faiz Madzlan M, Nadira Yusoff SN, Hassan Ahmad A, Ismail R, Nazrina Camalxaman S

Trans R Soc Trop Med Hyg, 2016 Apr;110(4):237-45.

PMID: 27076510 DOI: 10.1093/trstmh/trw015

Dengue fever (DF) is an urban vector-borne disease transmitted by Aedes aegypti and Aedes albopictus. Both species deposit their eggs in favorable breeding sites either in natural or artificial containers. An understanding of their habitat characteristics is crucial in curbing DF outbreaks

Hookworms in dogs of Kuching, Sarawak (north Borneo)

Choo J, Pang E, Prociv P

Trans R Soc Trop Med Hyg, 2000 4 5;94(1):21-2.

PMID: 10748891

Prophylactic and sporontocidal treatment of chloroquine resistant Plasmodium falciparum from Malaya

Clyde DF, DuPont HL, Miller RM, McCarthy VC

Trans R Soc Trop Med Hyg, 1970;64(6):834-8.

PMID: 4924648

Letter: Resistance to chloroquine of Plasmodium falciparum from Sabah

Clyde DF, Han CM, Huang YS

Trans R Soc Trop Med Hyg, 1973;67(1):146.

PMID: 4591211

Assessment of the association between three pfmdr1 point mutations and chloroquine resistance in vitro of Malaysian Plasmodium falciparum isolates

Cox-Singh J, Singh B, Alias A, Abdullah MS

Trans R Soc Trop Med Hyg, 1995 7 1;89(4):436-7.

PMID: 7570891

Letter: Toxoplasma antibody in West Malaysia (Peninsular Malaya)

Dasgupta B, Nandalal P

Trans R Soc Trop Med Hyg, 1974;68(2):173.

PMID: 4460305

Spatiotemporal spread of chikungunya virus in Sarawak, Malaysia

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.

The burden and epidemiology of polyparasitism among rural communities in Kano State, Nigeria

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.

An evaluation of the hydrogen sulphide water screening test and coliform counts for water quality assessment in rural Malaysia

Desmarchelier P, Lew A, Caique W, Knight S, Toodayan W, Isa AR, et al.

Trans R Soc Trop Med Hyg, 1992 7 1;86(4):448-50.

PMID: 1440833

The H2S water screening test and the membrane filtration faecal coliform count were compared with Escherichia coli counts for water samples collected from household water sources and domestic drinking water in rural Malaysia. Water samples were taken from 151 wells, 44 taps supplying water from the treated municipal supply and 192 domestic stored water supplies. E. coli were detected in 20% of the samples (42% of wells, 7% of tap water and 6% of drinking water). Excellent correlation (Spearman's rank correlation rs = 0.93) was found between the faecal coliform and E. coli counts for all sample types. The H2S method was poorly correlated whether read at 18 or 30 h. False positive rates were highest for well water, and false negative rates were highest for both well and drinking water samples, with low E. coli counts. The faecal coliform test was an excellent predictor of the presence of E. coli in these water samples, while the H2S test was very inadequate.

Apoptosis in Blastocystis spp. is related to subtype

Dhurga DB, Suresh KG, Tan TC, Chandramathi S

Trans R Soc Trop Med Hyg, 2012 Dec;106(12):725-30.

PMID: 23141370 DOI: 10.1016/j.trstmh.2012.08.005

Previous studies have shown that apoptosis-like features are observed in Blastocystis spp., an intestinal protozoan parasite, when exposed to the cytotoxic drug metronidazole (MTZ). This study reports that among the four subtypes of Blastocystis spp. investigated for rate of apoptosis when treated with MTZ, subtype 3 showed the highest significant increase after 72h of in vitro culture when treated with MTZ at 0.1mg/ml (79%; p<0.01) and 0.0001mg/ml (89%; p<0.001). The close correlation between viable cells and apoptotic cells for both dosages implies that the pathogenic potential of these isolates has been enhanced when treated with MTZ. This suggests that there is a mechanism in Blastocystis spp. that actually regulates the apoptotic process to produce higher number of viable cells when treated. Apoptosis may not just be programmed cell death but instead a mechanism to increase the number of viable cells to ensure survival during stressed conditions. The findings of the present study have an important contribution to influence chemotherapeutic approaches when developing drugs against the emerging Blastocystis spp. infections.

Trypanosome infections in Orang Aslis (Aborigines) in West Malaysia

Dissanaike AS, Ong HT, Kan SP

Trans R Soc Trop Med Hyg, 1974;68(6):494-5.

PMID: 4460313

Measurement of dengue epidemic spreading pattern using density analysis method: retrospective spatial statistical study of dengue in Subang Jaya, Malaysia, 2006-2010

Dom NC, Ahmad AH, Latif ZA, Ismail R

Trans R Soc Trop Med Hyg, 2013 Nov;107(11):715-22.

PMID: 24062522 DOI: 10.1093/trstmh/trt073

Dengue has emerged as one of the major public health problems in Malaysia. The Ministry of Health, Malaysia, is committed in monitoring and controlling this disease for many years. The objective of this study is to analyze the dengue outbreak pattern on a monthly basis in Subang Jaya in terms of their spatial dissemination and hotspot identification.

Studies on the resistance of malaria to chloroquine and to a combination of chloroquine and pyrimethamine in Peninsular Malaysia

Dondero TJ, Parsons RE, Ponnampalam JT

Trans R Soc Trop Med Hyg, 1976;70(2):145-8.

PMID: 785725

In vivo chloroquine resistance surveys, which allowed for detection of late recrudescing RI resistance, were conducted in three regions of Peninsular Malaysia, which were previously not recognized as having appreciable drug resistance. Among the 485 Plasmodium falciparum infections tested resistance rates ranged locally from 20% to 67% in those with parasitaemias over 1,000 per mm3, and 5% to 59% in all parasitaemias. The region found to have the most serious resistance was western Pahang. In one study a combination of chloroquine and pyrimethamine proved no more efficacious than chloroquine alone. Most of the resistance encountered was the late recrudescing RI type. There was no apparent correlation between drug resistance and Anopheles balabacensis as this species was not found despite intensive collections in two of the three main regions. There was no evidence of resistance among the 222 P. vivax and 35 P. malariae infections also tested.

Letter: Disappointing results in Malaysia with the "Dill Glazko" eosin colour tests for chloroquine in urine

Dondero TJ, Mariappan M

Trans R Soc Trop Med Hyg, 1974;68(4):338-9.

PMID: 4419901

Diurnally sub-periodic microfilarial pattern in Brugia malayi in West Malaysia

Dondero TJ, Sivanandam S

Trans R Soc Trop Med Hyg, 1971;65(5):691-3.

PMID: 5159155

Displaying publications 21 - 40 of 179 in total