In this study, 13 weeks (October to December 2012) of ovitrap surveillance was conducted in two suburban residential areas in Kampar town, Perak. A total of 17,310 Aedes mosquitoes were found in Taman Kampar Jaya, whereas Taman Juloong recorded a higher number at 19,042. Less than 1% of these were identified as Aedes aegypti, with the remaining confirmed as Aedes albopictus. The female Ae. albopictus were subsequently subjected to WHO standard diagnostic test kits against two pyrethroids (0.05% deltamethrin and 0.75% permethrin) and two organophosphates (1% fenitrothion and 5% malathion). The Ae. albopictus from both research sites were the most susceptible to deltamethrin, recording KT50 and KT95 response values of 15.84 minutes and 16.18 minutes; and 48.18 minutes and 49.44 minutes respectively. This was followed by permethrin (20.57 minutes and 17.52 minutes; 29.54 minutes and 54.54 minutes) and malathion (48.46 minutes and 62.69 minutes; 87.72 minutes and 141.04 minutes). Fenitrothion was found to be least effective towards Ae. albopictus; recording KT50 and KT95 response values of 150.29 minutes and 293.41 minutes for Taman Kampar Jaya, and 203.32 minutes and 408.07 minutes respectively for Taman Juloong. All tested Ae. albopictus showed 100% mortality after 24 hours post exposure. As both residential areas were fogged periodically by the municipal council; alternating between organophosphates and pyrethroids, thus, constant monitoring is crucial in light of the emergence of resistance noted in Ae. albopictus towards fenitrothion.
Malaria, caused by the Plasmodium parasite is still a health problem worldwide due to resistance of the pathogen to current anti-malarials. The search for new anti-malarial agents has become more crucial with the emergence of chloroquine-resistant Plasmodium falciparum strains. Protein kinases such as mitogen-activated protein kinase (MAPK), MAPK kinase, cyclin-dependent kinase (CDK) and glycogen synthase kinase- 3(GSK-3) of parasitic protozoa are potential drug targets. GSK-3 is an enzyme that plays a vital role in multiple cellular processes, and has been linked to pathogenesis of several diseases such as type II diabetes and Alzheimer's disease. In the present study, the antiplasmodial property of LiCl, a known GSK-3 inhibitor, was evaluated in vivo for its antimalarial effect against mice infected with Plasmodium berghei. Infected ICR mice were intraperitoneally administered with LiCl for four consecutive days before (prophylactic test) and after (suppressive test) inoculation of P. berghei-parasitised erythrocytes. Results from the suppressive test (post-infection LiCl treatment) showed inhibition of erythrocytic parasitemia development by 62.06%, 85.67% and 85.18% as compared to nontreated controls for the 100 mg/kg, 300 mg/kg and 600 mg/kg dosages respectively. Both 300 mg/kg and 600 mg/kg LiCl showed similar significant (P<0.05) suppressive values to that obtained with chloroquine-treated mice (86% suppression). The prophylactic test indicated a significantly (P<0.05) high protective effect on mice pre-treated with LiCl with suppression levels relatively comparable to chloroquine (84.07% and 86.26% suppression for the 300 mg/kg and 600 mg/kg LiCl dosages respectively versus 92.86% suppression by chloroquine). In both the suppressive and prophylactic tests, LiCl-treated animals survived longer than their non-treated counterparts. Mortality of the non-treated mice was 100% within 6 to 7 days of parasite inoculation whereas mice administered with LiCl survived beyond 9 days. Healthy non-infected mice administered with 600 mg/ kg LiCl for four consecutive days also showed decreased mortality compared to animals receiving lower doses of LiCl; three of the seven mice intraperitoneally injected with the former dose of LiCl did not survive more than 24 h after administration of LiCl whereas animals given the lower LiCl doses survived beyond four days of LiCl administration. To date, no direct evidence of anti-malarial activity in vivo or in vitro has been reported for LiCl. Evidence of anti-plasmodial activity of lithium in a mouse infection model is presented in this study.
Infective endocarditis (IE) is a relatively uncommon disease, but has been challenging to diagnose over the years. With the increasing incidence, variety of causative agents and the resistance of microorganisms towards antibiotics, there is still an occurrence of sudden death due to undiagnosed IE. The most common microorganism causing IE is Staphylococcus aureus. However, there is increasing prevalence of other microorganisms causing IE. This case report highlights a case of sudden death due to IE caused by a rare pathogen, Streptococcus constellatus which belongs to the Streptococcus anginosus group (Milleri group). A study noted the crude incidence of IE in 6 world regions ranged between 1.5 and 11.6 cases per 100,000 people. To date, there has been no previous report on sudden death due to IE caused by Streptococcus constellatus in Malaysia, neither in the forensic nor clinical setting. This case report underlined the characteristics and pathological features of this microorganism. The increasing incidence and variety of causative organisms in IE are important public health issues. It is vital for future studies to examine the risk factors of IE related to Streptococcus constellatus, to enhance better understanding, insight and awareness regarding the course of this disease. This in turn may facilitate preventive measures to avoid morbidity and mortality from this condition.
Blastocystis is one of the most common parasites inhabiting the intestinal tract of human and animals. Currently, human Blastocystis isolates are classified into nine subtypes (STs) based on the phylogeny of their small subunit ribosomal RNA (SSU rRNA) gene. Although its pathogenicity remains controversial, the possibility of zoonotic transmission was recognized since eight of the nine STs (except for ST9) have been reported in both humans and animals. A cross-sectional study was conducted to determine the prevalence and subtype distribution of Blastocystis isolated from humans and associated animals in an indigenous community with poor hygiene in Malaysia, where the risk of parasitic infection is high. A total of 275 stool samples were collected, subjected to DNA extraction and amplified by PCR assay. The Blastocystis-positive amplicons were then purified and sequenced. Phylogenetic tree of positive isolates, reference strains and outgroup were constructed using maximum likelihood method based on Hasegawa-KishinoYano+G+I model. The prevalence of Blastocystis infection among humans and domestic animals by PCR assay were 18.5% (45/243) and 6.3% (2/32), respectively. Through molecular phylogeny, 47 isolates were separated into five clusters containing isolates from both hosts. Among human isolates, ST3 (53.3%) was the predominant subtype, followed by ST1 (31.1%) and ST2 (15.6%). Chicken and cattle had lower proportions of ST6 (50%) and ST10 (50%), that were barely seen in humans. The distinct distributions of the most important STs among the host animals as well as humans examined demonstrate that there is various host-specific subtypes in the lifecycle of Blastocystis.
An appropriate pH maintenance within a membrane-enclosed organelle is vital for the occurrence of biological processes. Artemisinin (ART), a potent antimalarial drug has been reported to target the digestive vacuole (DV) of Plasmodium falciparum, which might alter the pH of the organelle, thereby impairing the hemoglobin degradation and subsequent heme detoxification. Hence, a flow cytometry-based technique using fluorescein isothiocyanate-dextran (FITC-dextran) as a ratiometric pH probe was employed to measure the pH of the DV of the malaria parasite treated with ART. Based on the pH calibration curve generated, the steady-state pH of the acidic DV of the non-treated parasites was 5.42 ± 0.11, indicating that FITC-dextran is suitable for detection of physiological pH of the organelle. The alteration of the DV pH occurred when the parasites were treated with ART even at the sub-lethal concentrations (15 and 30 nM) used. The similar effect was shown by the parasites treated with a standard proton pump inhibitor, concanamycin A. This suggests that ART might have altered the DV pH at lower levels than the level needed to kill the parasite. This study has important implications in designing new ART treatment strategies and in generating new endoperoxide-based antimalarial drugs pertaining to the interruption of the pH regulation of the malaria parasite's DV.
Various clinical symptoms are caused by dengue virus ranging from mild fever to severe hemorrhagic fever while there is no successful anti-dengue therapeutics available. Among different strategies towards identifying and developing anti-dengue therapeutics, testing anti-dengue properties of known drugs could represent an efficient strategy for which information of its medical approval, toxicity and side effects is readily available. In this study, we evaluated the antiviral activity of some medical compounds towards dengue NS2B-NS3 protease (DENV2 NS2B-NS3pro) as a target to inhibit dengue virus replication. Mefenamic acid, a non-steroid anti inflammatory drug and doxycycline, a derivative antibiotic of tetracycline both showed significant inhibition potential against DENV2 NS2B-NS3pro Ki values 32 ± 2 μM and 55 ± 5 μM respectively. The effective cytotoxic concentrations of 50% (CC50) against Vero cells were evaluated for mefenamic acid (150 ± 5 μM) and doxycycline (125 ± 4 μM). Concentrations lower than CC50 were used to test the inhibition potential of these compounds against DENV2 replication in Vero cells. The results showed significant reduction in viral load after applying mefenamic acid and doxycyline in concentration dependent manner. Mefenamic acid reduced viral RNA at EC50 of 32 ± 4 μM whilst doxycycline EC50 was 40 ± 3 μM. Mefenamic acid showed higher selectivity against dengue virus replication in vitro compared to doxycycline. These findings underline the need for further experimental and clinical studies on these drugs utilizing its anti-dengue and anti-inflammatory activities to attenuate the clinical symptoms of dengue infection.
Insects found associated with corpse can be used as one of the indicators in estimating postmortem interval (PMI). The objective of this study was to compare the stages of decomposition and faunal succession between a partially burnt pig (Sus scrofa Linnaeus) and natural pig (as control). The burning simulated a real crime whereby the victim was burnt by murderer. Two young pigs weighed approximately 10 kg were used in this study. Both pigs died from pneumonia and immediately placed in an oil palm plantation near a pig farm in Tanjung Sepat, Selangor, Malaysia. One pig was partially burnt by 1-liter petrol while the other served as control. Both carcasses were visited twice per day for the first week and once thereafter. Adult flies and larvae on the carcasses were collected and later processed in a forensic entomology laboratory. Results showed that there was no significant difference between the rate of decomposition and sequence of faunal succession on both pig carcasses. Both carcasses were completely decomposed to remain stage after nine days. The species of flies visiting the pig carcasses consisted of blow flies (Chrysomya megacephala, Chrysomya rufifacies, Hemipyrellia ligurriens), flesh fly (Sarcophagidae.), muscid fly (Ophyra spinigera), soldier fly (Hermetia illucens), coffin fly (Phoridae) and scavenger fly (Sepsidae). The only difference noted was in the number of adult flies, whereby more flies were seen in the control carcass. Faunal succession on both pig carcasses was in the following sequence: Calliphoridae, Sarcophagidae, Muscidae, Phoridae and lastly Stratiomyidae. However, there was overlap in the appearance of members of these families. Blowflies continued to oviposit on both carcasses. Hence postmortem interval (PMI) can still be estimated from the partially burnt pig carcass.
Edible bird nests (EBNs) are consumed worldwide for various health benefits. EBNs are nests built from the saliva of swiftlets of Aerodramus species. The global market for EBNs is on the rise, especially from Hong Kong and mainland China. In the past, EBNs were harvested mainly from natural caves; however in the recent years, there has been a rapid growth of swiftlet farming. Little is known about the actual composition of EBNs except for protein, carbohydrate, ash and lipid contents, amino acids, vitamins and macro/ micronutrients. Besides the biochemical components of EBNs, are there any other structures that are associated with EBNs? This paper reports on the structural analysis of raw unprocessed farm and processed commercial EBNs. The raw EBNs were purchased from swiftlet farms in five locations in Peninsula Malaysia: Kuala Sanglang (Perlis; 6° 16' 0"N, 100° 12' 0"E), Pantai Remis (Perak; 4º 27' 0" N, 100º 38' 0" E), Kluang (Johor; 02º 012 303N 103º 192 583E), Kajang (Selangor; 2º 59' 0"N, 101º 47' 0"E) and Kota Bharu (Kelantan; 6º 8' 0"N, 102º 15' 0"E). The commercial nests were purchased from five different Chinese traditional medicinal shops (Companies A-E). A portion of each EBN was randomly broken into small fragments, attached to carbon tape and coated with gold and palladium particles for examination and photography under a scanning electron microscope. Structural analysis revealed the presence of mites, fungi, bacteria and feather strands on both the raw and commercial nests. Mite eggshells and faecal pellets, and body parts of other arthropods were seen only in the raw nests. The commercial nests had a variety of unidentified structures and substances coated on the nests' surfaces that were not found on the raw nests. The presence of these contaminants may jeopardise the quality of EBNs and pose health risks to consumers. Further identification of the mites and their allergens, fungi and bacteria are on-going and will be reported separately.
Infections and mTalignancies are common causes of pleural effusion. Among infectious causes, hyperinfection syndrome of Strongyloides stercoralis may occur in immunosuppressive patient. A 62-year-old man, known case of Non-Hodgkin lymphoma (NHL) was presented with recurrent NHL stage IV and had undergone salvage chemotherapy. Patient subsequently developed pneumonia with bilateral pleural effusion and ascites. We reported rhabditiform larvae of S. stercoralis in pleural fluid of both lungs without infiltration by lymphoma cells. Stool for microscopic examination also revealed rhabditiform larvae of S. stercoralis. This patient was a known case of NHL receiving chemotherapy resulting in immunosuppression state. Although S. stercoralis infection is not very common compared to other parasitic infections, it is common in immunosuppressive patients and may present with hyperinfection. Therefore, awareness of this parasite should be kept in mind in immunosuppressive patients.
Transmission of soil-transmitted helminthes infection is by faecal oral route, and is influenced by food preference. Kelantanese love to consume ulam which are raw vegetables and herbs. Some of the herbs grow on grounds with high humidity and are abundant near drainage areas, these are also places with higher likelihood of harbouring viable parasite ova. The aim of this study was to determine the prevalence of soiltransmitted helminthes in vegetables, herbs and fruits found in our local setting. The results by microscopy showed that there was no helminthes ovum or protozoan parasite in the samples. However, Strongyloides stercoralis rhabdatiform larvae were identified in water samples used to wash pegaga, kesum and water spinach, and the number of larvae observed were 152, 9 and 16 respectively. Analysis by real-time PCR confirmed the microscopic observation of this helminth. This study highlighted that vegetables and herbs are likely sources of Strongyloides stercoralis infection in Kota Bharu, Kelantan. Thus vegetable sellers as well as the food handlers are the two important groups who are at high risk of acquiring the infection.
Strongyloides stercoralis is a widespread, soil-transmitted helminth affecting humans. Autoinfection occurs in S. stercoralis infection and this leads to a continuous build-up of worm burden in human host. This may lead to hyperinfection syndrome which has the potential to cause serious life-threatening disease especially in immunocompromised and immunosuppressed patients. Thus, patient with underlying risk factors should be suspicious of having this infection as severe strongyloidiasis carries a high mortality rate if the diagnosis is delayed. Here, we report a case of S. stercoralis hyperinfection in a diabetic patient.
Diplazium esculentum is an edible fern commonly consumed by the local community in Malaysia either as food or medicine. Isolation work on the ethyl acetate extract of the stem of D. esculentum resulted in the purification of two steroids, subsequently identified as stigmasterol (compound 1) and ergosterol5,8-endoperoxide (compound 2). Upon further testing, compound 2 displayed strong inhibitory activity against the Plasmodium falciparum 3D7 (chloroquine-sensitive) strain, with an IC50 of 4.27±1.15 µM, while compound 1 was inactive. In silico data revealed that compound 2 showed good binding affinity to P. falciparum-Sarco endoplasmic reticulum calcium-dependent ATPase (PfATP6); however, compound 1 did not show an antiplasmodial effect due to the lack of a peroxide moiety in the chemical structure. Our data suggested that the antiplasmodial activity of compound 2 from D. esculentum might be due to the inhibition of PfATP6, which resulted in both in vitro and in silico inhibitory properties.
Three new techniques of sterilising maggots of Lucilia cuprina for the purpose of debriding intractable wounds were studied. These techniques were utilisation of ultra-violet C (UVC) and maggot sterilisation with disinfectants. The status of sterility was checked on nutrient agar and blood agar and confirmed with staining. The indicators for the effectiveness of the methods were sterility and survival rate of the eggs or larvae. Egg sterilisation with UVC had the lowest hatching rate (16+/-0.00%) while egg sterilisation with disinfectants showed high hatching rate (36.67+/-4.41%) but low maggot survival rate (31.67+/-1.67%). Sterilisation of the maggots was the most suitable, since the survival rate was the highest (88.67+/-0.88%). Complete sterility was achieved in all cases, except that Proteus mirabilis was consistently found. However, the presence of this microorganism was considered beneficial.
The continued absence of an effective and safe tetravalent dengue vaccine and the lack of specific anti-viral treatment have made mosquito vector control using chemical insecticides as the mainstream for dengue prevention and control. However, the long-term use of chemical insecticides may induce resistance. Hence detection of insecticide resistance in dengue vectors is crucially important in ensuring the insecticide-based intervention in dengue control program is still effective and reliable. In this study, the susceptibility status of Aedes aegypti from five selected dengue hotspots in Klang Valley, Malaysia against pyrethroids was determined by employing the World Health Organization (WHO) protocol of adult bioassay. Four types of pyrethroids were tested against adult female Aedes aegypti to determine the knockdown rate, post 24-h adult mortality and resistance ratio. All field-collected Aedes aegypti strains were resistant to the four pyrethroids tested, except for the Taman Sungai Jelok (TSJ) strain. Permethrin exhibited the lowest knockdown rate against Aedes aegypti, followed by deltamethrin, cyfluthrin and lambda-cyhalothrin. This present study indicated the widespread of pyrethroid resistance in Aedes aegypti in Klang Valley, indicating the needs of implementing alternative measures in vector control program. The data in this study can be utilised as an input for insecticide resistance management of Aedes aegypti in Malaysia.
The nuisance bites of blackflies and transmission of Onchocerca volvulus, which causes onchocerciasis, constitutes a threat to public health and an impediment to food production in rural and riverine communities in Nigeria. The entomological profile of onchocerciasis at Adani, Nigeria, was investigated from August 2010 to January 2011 to determine the transmission of O. volvulus after 15 years of ivermectin distribution in the area. A total of 548 adult female blackflies of the Simulium damnosum complex were caught using human baits and dissected. Of this number, 248 flies were caught in the wet season (August to October), while 300 flies were caught in the dry season (November to January). The relative abundance of flies at Adani varied from 21 in December to 243 in January. The monthly catches between September and October and between December and January were significantly different. The monthly population density of the flies ranged from 0.5Flies/Man/Hour (FMH) in December to 5.5FMH in January. The diurnal biting pattern of the S. damnosum complex at the site showed a bimodal peak of activity with the evening peak being higher than the morning peak except in October when the morning peak was higher than the evening peak. The morning peaks were observed between 7.00 am and 10.00 am, whereas the evening peaks occurred between 4.00 pm and 6.00 pm. The morning and evening biting peaks in all the months were not significantly different. Nulliparous flies accounted for 75.7% of the total catch, whereas 24.3% of the flies caught were parous. The infection, infective bites and transmission of O. volvulus during the study period were zero. This study suggests that transmission of O. volvulus has been halted and the flies are presently more nuisance biters than disease vectors since no stage of O. volvulus was found in the flies dissected.
Hand, foot, and mouth disease (HFMD) is a contagious childhood disease caused by enteroviruses including enterovirus A71 (EV-A71), coxsackievirus A6 (CV-A6) and CV-A16 transmitted via direct and indirect contact. Different types of toy surfaces can affect the stability of viruses. Understanding the stability of enteroviruses on toys provides insightful data for effective disinfection in kindergartens or homes. Porous (ethylene-vinyl acetate mat foam, paper, pinewood, polyester fabric, and squishy polyurethane foam) and non-porous (acrylonitrile butadiene styrene plastic and stainless-steel coin) surfaces were inoculated with EV-A71 at 4, 24, and 35°C, and coxsackieviruses at 24°C. Infectious enteroviruses were recovered and titred in median tissue culture infectious dose assay (TCID50). Atomic force microscopy (AFM) images were taken from surfaces to examine association of surface roughness with virus stability. Overall, infectious enteroviruses were persistent on all non-porous and porous surfaces. Virus persistence was longest at 4°C followed by 24°C and 35°C. EV-A71 half-lives ranged between 6.4-12.8 hours at 4°C, 2.4-6.7 hours at 24°C, and 0.13-2.7 hours at 35°C. At lower virus titres exposed to 24°C, half-lives of enteroviruses ranged from 0.1-1.4 hours. Surface roughness values from AFM suggested smooth surfaces of non-porous surfaces were associated with better virus stability. Temperature, enterovirus concentration, and type of surface affected persistence and stability of enteroviruses. Our findings suggest both porous and non-porous surfaces in kindergartens allow enterovirus persistence and should be frequently disinfected to curb HFMD outbreaks in kindergartens.
The type and amount of resources available significantly influences the structure and dynamics of food webs. In this study, we analyzed differences in species richness of scavengers based on carcass type in Riyadh, Saudi Arabia. We collected insects from experimental carcasses of three different types, domestic dogs (Canidae, Canis lupus familiaris), Hijazi goats (Bovidae, Capra aegagrus hircus), and camels (Camelidae, Camelus dromedarius). Data collection was conducted during the decay stage in June, 2016. We used mitochondrial cytochrome c oxidase subunit I (mtCOI) barcodes as a marker for the molecular identification of the scavenger insects. The results showed that there were more insects on the camels and goats than the dogs. In total, seven species were found on all carrions. Six species were found on the camels and goats, but only five were found on the dog. Musca domestica was the most collected species of flies whereas, Necrobia rufipes was the most collected species of beetles. Overall, this study showed that carrion type had an effect on the type and number of insects attracted to the carrions. Thus, one of the significant factors that influence the associated scavenger assemblage is a carcass type.
Three species composition surveys were conducted in a rural location in Kedah and an urban location in Pulau Pinang. Two of the surveys were conducted in November 2003, the first was at the Kedah site and the second was at the Pulau Pinang site. The third survey was conducted at the Pulau Pinang site again on the last week of April 2004. All these surveys were conducted one week prior to field evaluations of commercial chemical fly baits. The predominant species recovered from the surveys was the house fly, Musca domestica, which ranked first in prevalence in all three studies. Catches of Musca sorbens, Chrysoma megacephala and Lucillia cuprina were lower than M. domestica. Sarcophaga sp. was not present at the Kedah site and was only present at the Pulau Pinang site during the survey in April 2004. The other fly species present at the Kedah site were Megaselia sp., Psycoda sp., Piophila sp. and Fannia sp. These species were scarce and never exceeded 1% of the total catch.
The adult population and species composition of mosquitoes collected in Ranau, Sabah are described. A total of 5956 mosquitoes representing 8 genera and 41 species were collected using human landing catch, indoor and outdoor. Anopheles maculatus was the most common species (15.6%) followed by Culex quinquefasciatus (12.8%), Culex pseudovishnui (12.1%), Anopheles balabacensis (11.1%), Culex vishnui (9.7%), Aedes vexans (9.6%), Culex tritaeniorhyncus (6.6%), Anopheles donaldi (5.6%) and others in very small percentage.
A 14-months survey was carried out to identify the species composition of Anopheles mosquitoes from Kampung Bongor, Grik, Perak. Adding to that, a preliminary one month mosquito population screening was done at Kampung Tepin, Serian, Sarawak. Consequently, the insecticide susceptibility status of a pyrethroid was tested against two selected species of Anopheles collected from these two locations in Malaysia. A total of 4,497 Anopheles from 11 species were identified from collections in Kampung Bongor, whereas 2,654 An. letifer were collected from Kampung Tepin. The An. maculatus of Kampung Bongor and An. letifer of Kampung Tepin were then selected and tested using WHO standard diagnostic test kits and impregnated papers with 0.75% permethrin. The response values of KT50 and KT95 for An. maculatus were recorded at 28.09 minutes and 62.98 minutes respectively. Anopheles letifer recorded much slower response values of KT50 and KT95, which was at 35.09 minutes and 73.03 minutes respectively. Both An. maculatus and An. letifer showed 100% mortality after 24 hours holding period. The results indicate that both species were still susceptible to the tested pyrethroid. For effective vector control and resistance management, accurate and periodic insecticide resistance monitoring should be undertaken especially in rural areas with agricultural usage of insecticides.