A study of chikungunya virus was carried out to establish Reverse Transcriptase- Polymerase Chain Reaction (RT-PCR) as a rapid detection technique of the virus. The susceptibility of lab-colonized Aedes aegypti to chikungunya virus was also determined. Artificial membrane feeding technique was used to orally feed the mosquitoes with a human isolate of chikungunya virus. A total of 100 fully engorged female Ae. aegypti were obtained and maintained for 7 days. Seventy of them survived and then pooled at 10 individuals per pool. Total RNA was extracted from the samples and RT-PCR amplifications were carried out. Five out of 7 pools showed positive PCR band at 350-bp, indicating Ae. aegypti is a potential vector of chikungunya virus. The minimum infection rate (MIR) was 71% within these laboratory colonies. RT-PCR is a sensitive technique that is useful in detecting infected mosquitoes in epidemic areas. This technique can de used as a rapid detection method and provide an early virologic surveillance systems of chikungunya virus infected mosquitoes.
Field bioefficacy of residual-sprayed deltamethrin against Aedes vectors was evaluated in an urban residential area in Kuala Lumpur. The trial area consisted of single storey wood-brick houses and a block of flat. The houses were treated with outdoor residual spraying while the flat was used as an untreated control. Initial pre-survey using ovitrap surveillance indicated high Aedes population in the area. Deltamethrin WG was sprayed at a dosage of 25mg/m2 using a compression sprayer. The effectiveness of deltamethrin was determined by wall bioassay and ovitrap surveillance. The residual activity of 25mg/m2 deltamethrin was still effective for 6 weeks after treatment, based on biweekly bioassay results. Bioassay also indicated that both Aedes aegypti and Aedes albopictus were more susceptible on the wooden surfaces than on brick. Aedes aegypti was more susceptible than Ae. albopictus against deltamethrin. Residual spraying of deltamethrin was not very effective against Aedes in this study since the Aedes population in the study area did not reduce as indicated by the total number of larvae collected using the ovitrap (Wilcoxon Sign Test, p> 0.05). Further studies are required to improve the effectiveness of residual spraying against Aedes vectors.
There is no doubt that on a global basis, Haemonchus contortus is by far the most important parasite of small ruminants (sheep and goats). This is particularly more so now, with the development of high levels of resistance to both the broad and narrow spectrum anthelmintic drugs in H. contortus throughout the world. Epidemiological studies describe the lower environmental limits for haemonchosis to occur in sheep, as being a mean monthly temperature of 18C and approximately 50mm rainfall. Thus it has been generally recognised that H. contortus is a problem parasite restricted to the warm, wet countries where sheep and goats are raised. However, recent evidence shows that this parasite is apparently common even in northern Europe. Thus the need for sustainable control strategies for H. contortus is becoming much more pressing. This report highlights two examples of sustainable and highly efficient control programmes for H. contortus, that can be implemented in regions at the extremes of its geographic range (Malaysia and Sweden), where the authors have had direct involvement.
This study was conducted to evaluate the anthelmintic effect of neem (Azadirachta indica) on nematode parasites of sheep. Twelve Santa Ines cross bred sheep from a government farm were randomly selected and equally divided into control (n = 6) and treated groups (n =6). Faecal egg counts (FEC) using the modified McMaster technique and the FAMACHA score for assessing clinical anaemia were carried out daily and recorded for 6 weeks. At the end of the study all the animals were slaughtered and the total worm count (TWC) was done. The results of FEC showed that there was no significant difference between the control and treated group (p = 0.081). However, worm burden estimations showed that the number of parasites was significantly higher in the control group compared to the treated group (p < 0.05). This result indicated that feeding Neem had an effect on worm numbers in sheep, but was not reflected in their faecal egg counts. Further work is needed to reconfirm the effect of Neem on helminth infections of sheep.
Some 2,000 species of mites of the family Trombiculidae are known in the world. The 6-legged larvae are mostly ectoparasites of reptiles, birds, mammals and invertebrates. Their 8-legged active nymphs and adults are free-living predators. In the Asia-Pacific region, a few species in various genera are vectors of scrub typhus and scrub-itch. In this a paper, a very bizarre trombiculid species, Vatacarus ipoides Southcott 1957, endoparasitic in the trachea of the amphibious sea snake, Laticauda colubrina (Schenider) is re-described based mostly on new-born larvae reared in the laboratory. Life history study of the mite produced very novel and interesting results. A brief account of the life-cycle was presented at the first laboratory demonstration of the Malaysian Society of Parasitology and Tropical Medicine Meeting by Nadchatram and Audy (1965). The life history is illustrated and described here in greater detail. The active nymphal, and the akinetic teleiophane stages are bypassed, which is unusual in the life-cycle of the family Trombiculidae. Also, the larva is the only stage in the life-cycle that feeds. The sexes are predetermined in the larval neosomatic stage and give rise to small males and bigger females. Having obtained adults of the species, by rearing, it is deemed unnecessary for the original proposal by Southcott to erect a new family, Vatacaridae, because the adults share all the attributes of the family Trombiculidae. The male and female obtained through laboratory rearing are illustrated for the first time. Relationship of V. ipoides with Laticauda snakes show close host-specificity, in a group of acarines that are generally habitat-specific. Possible explanations for their association are discussed. The unusual morphology and the formation of new structures during an instar is of ontogenetic and evolutionary importance. The hypertrophic larvae are superficially vermiform, rather than typically acarine in shape. This, and other biological features, necessitated the proposal of new morphological terms, and they are discussed here.
There were a spate of recent complaints of insect bites and the entomological specimens received from various sources were identified to be those of cat flea (Ctenocephalides felis) and rat flea (Xenopsylla cheopis), the tropical bed-bug (Cimex hemipterus) and the dog louse (Heterodoxus spiniger). Only the fleas and the bed-bug are known to attack humans.
A modified micromethod for measuring urine iodine was successfully established and validated. The micromethod showed good correlation with the method used by several World Health Organization (WHO) collaborative laboratories (y = 0.9342x + 4.6213; r = 0.962; p = 0.01; n = 50). The micromethod also showed good agreement when compared to the reference WHO method. The sensitivity of the assay was 13.809 ug/L (n = 8) and mean recoveries were 114, 103 and 106% at concentrations of 30, 40 and 50 ug/L (n = 3) respectively. At iodine concentrations of 51 +/- 15.5, 108 +/- 32.4 and 149 +/- 38.6 ug/L, intra-assay coefficient of variations (CVs) were 13%, 7% and 5% respectively (n = 20), and inter-assay CVs were 10%, 15% and 7% respectively (n = 10). The assay showed good linearity plot (y = 1.0407x + 60.451; r = 0.993; n = 3).
A study on causes of lung condemnation in 25 abattoirs from peninsular Malaysia for a period of seven years (1998-2004) was conducted by examining the records at the Department of Veterinary Services headquarters in Kuala Lumpur. A total of 5.3% of lungs from 233,417 cattle and buffaloes were condemned from 1998 to 2004. The main cause of condemnation was congestion (2.98%). The percentage of lungs that were condemned due to parasitic infection among the total population slaughtered was low (0.11%). Parasitic infection contributed to 2.1% of all lungs condemned. It was also found that the prevalence of parasitic infection in the lungs was generally much higher in buffaloes than in cattle.
Colorectal carcinoma ranks third among ten leading causes of cancer in Malaysia. The colorectal carcinoma tumourigenesis involves the inactivation of tumour suppressor genes, and activation of proto-oncogenes. The p53 is one of the tumour suppressor genes that is involved in the colorectal carcinogenesis. The p53 gene is located on human chromosome 17p13.1 and comprises of 11 exons. Deficiencies in the p53 gene can cause the cancerous cells to spread to distant organs such as liver, lungs, lymph nodes, spine and bone. The most common p53 abnormalities that can lead to the metastasis of colorectal tumours are mutation and deregulation of the gene. In this study, nine colorectal carcinoma samples were used to establish a simple and sensitive strategy in the study on in vivo p53 expression by using realtime LightCycler SYBR Green I technology.
Studies were carried out on the residual efficacy of Bacillus thuringiensis H-14 (water dispersible granule, VectoBac ABG 6511) as direct application in the control of Aedes larvae in the field. Field Aedes sp populations in the earthen and glass jars were predetermined before initiation of the trial. On confirmation of the presence of Aedes species in the designated area, Sungai Nibong Kecil, Penang Island, Malaysia, Bti was introduced in the 55L earthen and 3L glass jars). Two test designs were carried out. The first design had treated water replenished daily with 6L of seasoned water and the second design is without the replenishment of water but evaporated water was replenished. Bti was effective in the field for at least 35 days with more than 80% reduction in the Aedes larvae in the treated containers. For earthen jars with daily replenishment of water, 100% reduction was recorded for the first 3 days, while more than 80% reduction was recorded up to day 40. At day 60, Bti still provided an efficacy of 54.32 +/- 4.61 (%) of reduction. Whilst for earthen jars without daily replenishment of water, 100% reduction was recorded for the first 5 days, while more than 80% of reduction was recorded up to day 40. For the glass jars studied, similar efficacy was observed. In jars with daily replenishment of water a better larval control was observed. Percentage of reduction from day 50 to 60 for replenishment of water was between 50 to 70% compared to without replenishment of water with less than 40%.
Amoebiasis is an infectious diseased caused by parasitic one-celled protozoan called Entamoeba histolytica. Numerous protozoa also can inhabit the gastro-intestinal tract of human. Majority of these protozoa are non-pathogenic commensals or only causes disease under certain circumstances. Morphologically, E. histolytica, the invasive form, share the same characteristic with the nonpathogenic form, E. dispar. Both strains can be distinguished by using DNA identification. Many previous researches in Malaysia only reported infection with E. histolytica infection. Therefore in this study we tried to classify infection among the aborigines in Cameron Highland as true E. histolytica or E. dispar by Nested Polymerase Chain Reaction (Nested PCR) and Restriction enzyme (RE) digestion. Results showed that 31 samples were positive by microscopic examination, however of these 28 (13.2%) samples were positive for E. histolytica and 12 (5.6%) samples were positive for E. dispar by molecular tools.
The objective of this study was to elucidate the association of various risk factors with dengue cases reported in Lundu district, Sarawak, by analyzing the interaction between environmental, entomological, socio-demographic factors. Besides conventional entomological, serological and house surveys, this study also used GIS technology to generate geographic and environmental data on Aedes albopictus and dengue transmission. Seven villages were chosen based on the high number of dengue cases reported. A total of 551 households were surveyed. An overall description of the socio-demographic background and basic facilities was presented together with entomological and geographical profiles. For serological and ovitrap studies, systematic random sampling was used. Serological tests indicated that 23.7% of the 215 samples had a history of dengue, either recent or previous infections. Two samples (0.9%) were confirmed by IgM ELISA and 49 samples (22.8%) had IgG responses. A total of 32,838 Aedes albopictus eggs were collected in 56 days of trapping. Cluster sampling was also done to determine whether any of the risk factors (entomological or geographical) were influenced by geographical location. These clusters were defined as border villages with East Kalimantan and roadside villages along Lundu/Biawas trunk road. The data collected were analyzed using SPSS version 10.01. Descriptive analysis using frequency, means, and median were used. To determine the association between variables and dengue cases reported, and to describe the differences between the two clusters of villages, two-sample t-test, and Pearson's Chi-Square were used. Accurate maps were produced with overlay and density function, which facilitates the map visualization and report generating phases. This study also highlights the use of differential Global Positioning System in mapping sites of 1m accuracy. Analysis of the data revealed there are significant differences in clusters of villages attributable to container density, house density, distance of the house from the main road, and number of Ae. albopictus eggs from ovitraps set indoor, outdoor and in dumping sites (Person's Chi-Square = 6.111, df = 1, p < 0.01). Further analysis using t-test showed that house density, container density, indoor mosquitoes egg count, outdoor mosquitoes egg count, and dumping sites mosquitoes egg count were higher at the roadside villages compared to border villages. A number of potential risk factors including those generated from GIS were investigated. None of the factors investigated in this study were associated with the dengue cases reported.
Smoking among adolescent is a public health concern in Malaysia. Multiple studies on smoking prevalence and its related factors have been conducted in Malaysia, however, they were specific to either urban or rural areas alone. Studies in mixed settlement areas (urban, rural, land development area) had not been intensively investigated. This study reports the prevalence, demographic and factors related to smoking amongst form four students in the district of Kota Tinggi, Johor. A cross-sectional study of 16-year old secondary school students in Kota Tinggi district was conducted using two-stage stratified, proportionate sampling in July 2005. The study instrument used was a validated structured questionnaire on smoking and its related factors. Smoking prevalence was found to be 29.7%. More than 50% of male students were smokers. Prevalence was highest in FELDA (Federal Land Development Authority) settlement areas. Smoking was associated with having a brother or friend who smokes and poor academic performance. The study revealed that smoking prevalence was high, especially among male students in land development schemes. This situation will contribute to high smoking-related health problems in the future if proper preventive measures are not taken accordingly.
Transmission electron microscopy (TEM) can provide high resolution imaging of biological specimens. The study is to establish the effects of a modified glutaraldehyde (GA) compare to the standard GA fixation on Acanthamoeba castellanii from TEM perspectives and thus provide precise and accurate information on the ultrastructure studies of the parasite. By increasing the contrast, the ultrastructures of the parasite were more evident. The TEM images were obtained from parasites fixed with the modified GA and the standard GA and then the area of the nucleus and the gray values of the image of the nucleus of the parasites were measured. The mean areas of the nucleus were found to be significantly reduced in the standard GA fixed parasites (12210.4 nm2) compared to the modified GA fixed parasites (8676.3 nm2) (p < 0.05). The mean gray values of the image were significantly reduced from 2024 in the standard GA fixed parasites (2024) to the modified GA fixed parasites (1636) (p < 0.05). The study shows that the modified GA produced significantly better contrast on TEM images of the A. castellanii compared to the standard GA. This was because the modified GA generated more free water molecules during fixation and the uptake of modified GA by the nucleus of the parasite organizing all protein constituents in the cell into a more closely packed configuration than that of the standard GA. With such properties, the modified GA is a better fixative providing better images for ultrastructures of the parasite.
Childhood obesity is an established problem in many countries and emerging in others. Epidemiological data on obesity in children is essential in order to plan public health policy and services. A study was conducted to determine the prevalence of obesity in schoolchildren in the fifth grade of elementary school (10-12 years old) in the district of Kuala Selangor. Ten schools of which five are in urban and five in rural areas were selected consisting of 699 eleven year old schoolchildren from the three major ethnic groups. Using international cut-off points for obesity, we report an overall prevalence of obesity of 7.2%. Prevalence of obesity in urban children is 7.2% whereas in rural children it is 7.0 %. Analysed by gender, there were 8.9% obese boys and 5.3% obese girls. Among the 3 major ethnic groups, the Malays had the highest prevalence of obesity at 9.3% followed by the Chinese with 6.6% while among Indians 3.0%. The data obtained from this study suggests that obesity in Kuala Selangor children is a cause for concern in urban and rural areas.
Malaria is a disease which is still endemic and has become a disastrous scourge because of the emergence of antimalarial drug resistant Plasmodium falciparum. A new approach in addressing this is in developing a combination drug. This study is to show the enhancement of antimalarial properties, when single compound, goniothalamin combine with standard drug, chloroquine. Based on 4 Day Test, percentage of parasite growth on treated infected mice were determined. Oral treatment with 1 mg/kg BW of chloroquine on experimental mice suppressed 70% and 76.7% of both Plasmodium yoelii and Plasmodium berghei, respectively. The infection of P. berghei in mice was inhibited less than 50% by goniothalamin individual treatment at all doses in this study. About 27.8% and 18.5% inhibition of infection were observed in P. yoelii infected mice treated with 30 mg/kg and 60 mg/kg of goniothalamin respectively and the suppression exceed more than 50% at higher doses (90 and 120 mg/kg). Combination of 1 mg/kg chloroquine with either 30 mg/kg or 60 mg/kg of goniothalamin decreased the parasitemia of P. yoelii infected mice more than 90% and prolong the survival up to 100% after treatment. Similar treatment to P. berghei infected mice only shows about 60% reduction of parasitemia. The study findings showed that antimalarial property of goniothalamin was enhanced by combination with chloroquine at lower dose of each drug.
A field study on foraging activity and proteinacous food preference was performed on the tropical fire ant (Solenopsis geminata) (Fabricius) at the School of Biological Sciences and Desasiswa Bakti Permai, Universiti Sains Malaysia (USM), Penang. Foraging activity studies of 4 colonies of S. geminata were conducted in the field for 24 hours. Foraging activity significantly increased 4 hours before sunset and maximum foraging occurred at midnight until early morning. Three types of proteinacous food; anchovy, meat and egg yolk were tested among the five colonies of S. geminata in the field. The egg yolk was the most preferred food (100%) followed by meat (31%) and anchovy (15%).
The detection of leptospires in patient blood in the first week of the disease using PCR provides an early diagnostic tool. PCR using two sets of primers (G1/G2 and B64-I/B64-II) tested with samples seeded with 23 leptospiral strains from pathogenic and non-pathogenic strains was able to amplify leptospiral DNA from pathogenic strains only. Of the 39 antibody negative samples collected from patients suspected for leptospirosis, only 1 sample (2.6%) was PCR positive. Using LSSP-PCR, the G2 primers allowed the characterization of Leptopira species to 10 different genetic signatures which may have epidemiological value in determining species involved in outbreaks. Leptospiral outer membrane proteins from three strains were purified and reacted against patients sera and gave rise to different profiles for pathogenic and non-pathogenic strains. Lymphocytes of mice injected with OMPs proliferated and released IFN(-3) when stimulated in vitro using Leptospira OMP as antigens. This suggests that an immune response could be established using leptospiral OMPs as a putative vaccine. OMPs were also used in a Dot-ELISA to detect antibodies against Leptospira pathogens in humans.
A truncated form of surface antigen 2 (SAG2) of the protozoan parasite Toxoplasma gondii was cloned and expressed in the methylotrophic yeast Pichia pastoris. This recombinant antigen, designated as recSAG2-N, contained only the N-terminal half of the native SAG2. The recSAG2-N was secreted by the Pichia pastoris into the culture supernatant, and it was harvested by using the trichloroacetic acid precipitation method. Specificity of recSAG2-N was evaluated in western blot assays. Fifty human serum samples, including 32 from confirmed cases of toxoplasmosis, were tested. Results from the assays showed that recSAG2-N reacted with sera from the toxoplasmosis cases only. In vivo experiments showed that serum from mice which received recSAG2-N reacted with the native SAG2 of T. gondii.
This is a cross-sectional study conducted from January to September 2004 in a group of school children aged 8 -10 years old. The schools and study subjects were selected using stratified systematic sampling technique. A total of 44 schools and 1100 subjects were selected from schools with iodinator and schools without iodinator. Samples collected were spot urine and drinking water. Dietary and iodised water consumption data were obtained from interviews. A total of 931 subjects (84.6%) responded; 558 (50.7%) from schools with iodinator and 373 (33.9%) from schools without iodinator. Results showed that in more than half (53.8%) of the schools with iodinators, mean water iodine level was below 25 microg/L. The study population in Terengganu was found to be mildly iodine deficient with an overall median urine iodine concentration (uIC) of 74 microg/L. Based on WHO criteria, 4.1% with uIC <20 microg/L (severe), 19.5% with uIC between 20-49 microg/L (moderate), 49.2% with uIC between 50-99 microg/L (mild) and 27.2% was iodine sufficient with uIC >100 microg/L. Majority of the study subjects were found to have high seafood intake (> 90%) and low in goitrogen food intake. This study suggests water iodinator system may not be a suitable method of supplying iodine and an alternative is needed in order to eradicate the iodine deficiency problem seen in some parts of Malaysia.