Dengue has become a global public health problem. Despite reactive efforts by the government in Malaysia, the dengue cases are on the increase. Adequate knowledge, positive attitude and correct practice for dengue control are essential to stamp out the disease. Hence, this study aims to assess the factors associated with dengue knowledge, attitude and practice (KAp), as well as the association with dengue igM and igG seropositivity. A community-based cross-sectional study was conducted in a closed, dengue endemic area with multi-storey dwellings. Five hundred individuals (aged 18 years and above) were approached for pre-tested KAp and seroprevalences assessment. the study showed only half of the total participants have good knowledge (50.7%) but they had insufficient knowledge about dengue during pregnancy. 53.2% of people had poor attitude and 50.2% reported poor practice for dengue control. Out of 85 respondents who agreed to participate in the dengue seroprevalence study, 74.1% (n = 63) were positive for dengue IgG and 7.1% (n = 6) were positive for dengue IgM. Among all sociodemographic variable, race is the only independent predicator for all KAp levels (p < 0.05). In conclusion, proactive and sustainable efforts are needed to bring a behavioural change among communities in order to fight dengue outbreaks in endemic areas. Dengue fever is a mosquito-borne viral disease caused by a flavivirus. There are four distinct serotypes of dengue virus, namely DEN-1, 2, 3 and 4. Female Aedes aegypti and Aedes albopictus mosquitoes are the primary and secondary vectors in Malaysia, respectively. Evidently, dengue is the most rapidly spreading arboviral disease in the world. The Global Burden of Disease reported that dengue incidence has multiplied to six-folds from 1990 to 2013, with Southeast Asia region contributing 52% of the disease burden 1. World Health Organisation (WHO) estimates that 50 million to 100 million cases occur annually 2 .The disease is currently endemic in more than 100 countries, with SouthEast Asia being among the worst affected region. Dengue fever was established in Malaysia ever since the first reported case of dengue in 1902. From then on, the numbers of cases continued to rise despite numerous initiatives undertaken by the Ministry of Health to curb the disease 3,4. According to WHO, the recent cumulative case count in Malaysia from 1 Jan to 2 Mac 2019 was 157% higher than that of the same period in 2018 5. In addition, a total of 79,151 dengue cases have been reported until end of July 2019 nationwide, with Selangor state contributing more than 50% of the cases (n = 40,849, 51.6%) 6. Vector control and surveillance is still the mainstay of dengue prevention strategies since there is no specific treatment for disease and vaccination remains a non-viable option 7. Local programs like Communications for Behavorial Changes (COMBI) in Malaysia have proved their potential effect in reducing dengue morbidity 8 but it requires understanding from community as well 9. Besides, vector control measures ...
Plasmodium knowlesi, a simian malaria parasite, has been in the limelight since a large focus of human P. knowlesi infection was reported from Sarawak (Malaysian Borneo) in 2004. Although this infection is transmitted across Southeast Asia, the largest number of cases has been reported from Malaysia. The increasing number of knowlesi malaria cases has been attributed to the use of molecular tools for detection, but environmental changes including deforestation likely play a major role by increasing human exposure to vector mosquitoes, which coexist with the macaque host. In addition, with the reduction in human malaria transmission in Southeast Asia, it is possible that human populations are at a greater risk of P. knowlesi infection due to diminishing cross-species immunity. Furthermore, the possibility of increasing exposure of humans to other simian Plasmodium parasites such as Plasmodium cynomolgi and Plasmodium inui should not be ignored. We here review the current status of these parasites in humans, macaques, and mosquitoes to support necessary reorientation of malaria control and elimination in the affected areas.
Originally known to cause simian malaria, Plasmodium knowlesi is now known as the fifth human malaria species. Since the publishing of a report that largely focused on human knowlesi cases in Sarawak in 2004, many more human cases have been reported in nearly all of the countries in Southeast Asia and in travelers returning from these countries. The zoonotic nature of this infection hinders malaria elimination efforts. In order to grasp the current perspective of knowlesi malaria, this literature review explores the different aspects of the disease including risk factors, diagnosis, treatment, and molecular and functional studies. Current studies do not provide sufficient data for an effective control program. Therefore, future direction for knowlesi research is highlighted here with a final aim of controlling, if not eliminating, the parasite.
Background Dengue is a serious public health problem worldwide, including in Selangor, Malaysia. Being an important vector of dengue virus, Aedes aegypti are subjected to control measures which rely heavily on the usage of insecticides. Evidently, insecticide resistance in Ae. aegypti , which arise from several different point mutations within the voltage-gated sodium channel genes, has been documented in many countries. Thus, this robust study was conducted in all nine districts of Selangor to understand the mechanisms of resistance to various insecticides in Ae. aegypti. Mosquitoes were collected from dengue epidemic and non-dengue outbreak areas in Selangor. Methods Using the Center for Disease Control and Prevention (CDC) bottle assays, the insecticide resistance status of nine different Ae. aegypti strains from Selangor was accessed. Synergism tests and biochemical assays were conducted to further understand the metabolic mechanisms of insecticide resistance. Polymerase chain reaction (PCR) amplification and sequencing of the IIP-IIS6 as well as IIIS4-IIIS6 regions of the sodium channel gene were performed to enable comparisons between susceptible and resistant mosquito strains. Additionally, genomic DNA was used for allele-specific PCR (AS-PCR) genotyping of the gene to detect the presence of F1534C, V1016G and S989P mutations. Results Adult female Ae. aegypti from various locations were susceptible to malathion and propoxur. However, they exhibited different levels of resistance against dichlorodiphenyltrichloroethane (DDT) and pyrethroids. The results of synergism tests and biochemical assays indicated that the mixed functions of oxidases and glutathione S-transferases contributed to the DDT and pyrethroid resistance observed in the present study. Besides detecting three single kdr mutations, namely F1534C, V1016G and S989P, co-occurrence of homozygous V1016G/S989P (double allele) and F1534C/V1016G/S989P (triple allele) mutations were also found in Ae. aegypti . As per the results, the three kdr mutations had positive correlations with the expressions of resistance to DDT and pyrethroids. Conclusions In view of the above outcomes, it is important to seek new tools for vector management instead of merely relying on insecticides. If the latter must be used, regular monitoring of insecticide resistance should also be carried out at all dengue epidemic areas. Since the eggs of Ae. aegypti can be easily transferred from one location to another, it is probable that insecticide-resistant Ae. aegypti can be found at non-dengue outbreak sites as well. Electronic supplementary material The online version of this article...
New antimalarial agents are identified and developed after extensive testing on Plasmodium falciparum parasites that can be grown in vitro . These susceptibility studies are important to inform lead optimisation and support further drug development. Until recently, little was known about the susceptibility of non-falciparum species as these had not been adapted to in vitro culture. The recent culture adaptation of P . knowlesi has therefore offered an opportunity to routinely define the drug susceptibility of this species, which is phylogenetically closer to all other human malarias than is P . falciparum. We compared the in vitro susceptibility of P . knowlesi and P . falciparum to a range of established and novel antimalarial agents under identical assay conditions. We demonstrated that P . knowlesi is significantly less susceptible than P . falciparum to six of the compounds tested; and notably these include three ATP4 inhibitors currently under development as novel antimalarial agents, and one investigational antimalarial, AN13762, which is 67 fold less effective against P . knowlesi . For the other compounds there was a less than two-fold difference in susceptibility between species. We then compared the susceptibility of a recent P . knowlesi isolate, UM01, to that of the well-established, older A1-H.1 clone. This recent isolate showed similar in vitro drug susceptibility to the A1-H.1 clone, supporting the ongoing use of the better characterised clone to further study drug susceptibility. Lastly, we used isobologram analysis to explore the interaction of a selection of drug combinations and showed similar drug interactions across species. The species differences in drug susceptibility reported by us here and previously, support adding in vitro drug screens against P . knowlesi to those using P . falciparum strains to inform new drug discovery and lead optimisation.
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