Displaying publications 1 - 20 of 298 in total

Abstract:
Sort:
  1. Hustedt J, Prasetyo DB, Fiorenzano JM, von Fricken ME, Hertz JC
    Parasit Vectors, 2022 Oct 05;15(1):355.
    PMID: 36199150 DOI: 10.1186/s13071-022-05464-8
    Phlebotomine sand flies are proven or suspected vectors of several pathogens of importance, including leishmaniasis, bartonellosis and sand fly fevers. Although sand flies have a worldwide distribution, there has been limited research published on sand flies and sand fly-borne pathogens throughout the Greater Mekong Sub-region (GMS). This review followed the PRISMA guidelines to determine the biodiversity and presence of phlebotomine sand flies and their associated pathogens in the GMS, specifically Cambodia, Thailand, the Lao People's Democratic Republic (Laos), Malaysia and Vietnam. A total of 1472 records were identified by searching electronic databases, scanning reference lists of articles and consulting experts in the field. After screening of title and abstracts, 178 records remained and were further screened for original data (n = 34), not having regional data (n = 14), duplication of data (n = 4), records not available (n = 4) and no language translation available (n = 2). A total of 120 studies were then included for full review, with 41 studies on sand fly-related disease in humans, 33 studies on sand fly-related disease in animals and 54 entomological studies focused on sand flies (5 papers contained data on > 1 category), with a majority of the overall data from Thailand. There were relatively few studies on each country, with the exception of Thailand, and the studies applied different methods to investigate sand flies and sand fly-borne diseases, impacting the ability to conduct meaningful meta-analysis. The findings suggest that leishmaniasis in humans and the presence of sand fly vectors have been reported across several GMS countries over the past 100 years, with local transmission in humans confirmed in Thailand and Vietnam. Additionally, local Mundinia species are likely transmitted by biting midges. Findings from this study provide a framework for future investigations to determine the geographic distribution and risk profiles of leishmaniasis and other associated sand fly-borne disease throughout the GMS. It is recommended that researchers expand surveillance efforts across the GMS, with an emphasis placed on entomological surveys, syndromic and asymptomatic monitoring in both humans and animals and molecular characterization of sand flies and sand fly-borne pathogens, particularly in the understudied countries of Cambodia, Vietnam and Laos.
    Matched MeSH terms: Insect Vectors
  2. Elia-Amira NMR, Chen CD, Low VL, Lau KW, Haziqah-Rashid A, Amelia-Yap ZH, et al.
    J Med Entomol, 2022 01 12;59(1):301-307.
    PMID: 34459477 DOI: 10.1093/jme/tjab146
    The efficacy of three groups of insect growth regulators, namely juvenile hormone mimics (methoprene and pyriproxyfen), chitin synthesis inhibitors (diflubenzuron and novaluron), and molting disruptor (cyromazine) was evaluated for the first time, against Aedes albopictus Skuse (Diptera: Culicidae) larvae from 14 districts in Sabah, Malaysia. The results showed that all field populations of Ae. albopictus were susceptible towards methoprene, pyriproxyfen, diflubenzuron, novaluron, and cyromazine, with resistance ratio values ranging from 0.50-0.90, 0.60-1.00, 0.67-1.17, 0.71-1.29, and 0.74-1.07, respectively. Overall, the efficacy assessment of insect growth regulators in this study showed promising outcomes and they could be further explored as an alternative to conventional insecticides.
    Matched MeSH terms: Insect Vectors/drug effects; Insect Vectors/growth & development
  3. Jeyaprakasam NK, Low VL, Liew JWK, Pramasivan S, Wan-Sulaiman WY, Saeung A, et al.
    Sci Rep, 2022 01 10;12(1):354.
    PMID: 35013403 DOI: 10.1038/s41598-021-04106-w
    Blood feeding and host-seeking behaviors of a mosquito play an imperative role in determining its vectorial capacity in transmitting pathogens. Unfortunately, limited information is available regarding blood feeding behavior of Anopheles species in Malaysia. Collection of resting Anopheles mosquitoes for blood meal analysis poses a great challenge especially for forest dwelling mosquitoes. Therefore, a laboratory-based study was conducted to evaluate the potential use of mosquitoes caught using human landing catch (HLC) for blood meal analysis, and subsequently to document blood feeding behavior of local Anopheles mosquitoes in Peninsular Malaysia. The laboratory-based experiment from this study revealed that mosquitoes caught using HLC had the potential to be used for blood meal analysis. Besides HLC, mosquitoes were also collected using manual aspirator and Mosquito Magnet. Overall, 47.4% of 321 field-caught Anopheles mosquitoes belonging to six species were positive for vertebrate host DNA in their blood meal. The most frequent blood meal source was human (45.9%) followed by wild boar (27.4%), dog (15.3%) and monkey (7.5%). Interestingly, only Anopheles cracens and Anopheles introlatus (Leucosphyrus Group) fed on monkey. This study further confirmed that members of the Leucosphyrus Group are the predominant vectors for knowlesi malaria transmission in Peninsular Malaysia mainly due to their simio-anthropophagic feeding behavior.
    Matched MeSH terms: Insect Vectors/metabolism*
  4. Teoh MC, Furusawa G, Veera Singham G
    Arch Microbiol, 2021 Jul;203(5):1891-1915.
    PMID: 33634321 DOI: 10.1007/s00203-021-02230-9
    Insects and bacteria are the most widespread groups of organisms found in nearly all habitats on earth, establishing diverse interactions that encompass the entire range of possible symbiotic associations from strict parasitism to obligate mutualism. The complexity of their interactions is instrumental in shaping the roles of insects in the environment, meanwhile ensuring the survival and persistence of the associated bacteria. This review aims to provide detailed insight on the multifaceted symbiosis between one of the most versatile bacterial genera, Pseudomonas (Gammaproteobacteria: Pseudomonadaceae) and a diverse group of insect species. The Pseudomonas engages with varied interactions with insects, being either a pathogen or beneficial endosymbiont, as well as using insects as vectors. In addition, this review also provides updates on existing and potential applications of Pseudomonas and their numerous insecticidal metabolites as biocontrol agents against pest insects for the improvement of integrated pest management strategies. Here, we have summarized several known modes of action and the virulence factors of entomopathogenic Pseudomonas strains essential for their pathogenicity against insects. Meanwhile, the beneficial interactions between pseudomonads and insects are currently limited to a few known insect taxa, despite numerous studies reporting identification of pseudomonads in the guts and haemocoel of various insect species. The vector-symbiont association between pseudomonads and insects can be diverse from strict phoresy to a role switch from commensalism to parasitism following a dose-dependent response. Overall, the pseudomonads appeared to have evolved independently to be either exclusively pathogenic or beneficial towards insects.
    Matched MeSH terms: Insect Vectors/classification; Insect Vectors/microbiology
  5. Dinesh DS, Hassan F, Kumar V, Kesari S, Topno RK, Yadav RS
    Trop Med Int Health, 2021 07;26(7):823-828.
    PMID: 33733549 DOI: 10.1111/tmi.13576
    OBJECTIVES: Indoor residual spraying (IRS) with insecticides is the main vector control intervention for the elimination of visceral leishmaniasis in India. After a change in IRS policy in 2015 due to widespread resistance of Phlebotomus argentipes to DDT, IRS with DDT was replaced with alpha-cypermethrin IRS in 2016. The objective of the present study was to evaluate the susceptibility of P. argentipes to DDT and its alternatives, namely malathion and pirimiphos-methyl (organophosphates); alpha-cypermethrin, deltamethrin, lambda-cyhalothrin and permethrin (pyrethroids), and bendiocarb and propoxur (carbamates), in support of visceral leishmaniasis elimination in India.

    METHODS: Phlebotomus argentipes sandflies were collected from the visceral-leishmaniasis endemic states of Bihar, Jharkhand and West Bengal. In the WHO tube tests, the phenotypic susceptibility of F1, 2-day old, non-blood fed females were determined against filter papers impregnated with DDT 4%, malathion 5%, pirimiphos-methyl 0.25%, alpha-cypermethrin 0.05%, deltamethrin 0.05%, lambda-cyhalothrin 0.05%, permethrin 0.75%, bendiocarb 0.1% and propoxur 0.1%, which were sourced from Universiti Sains Malaysia. The knockdown of sandflies after 1-h exposure and mortality at 24 h after the 1-h exposure period were scored.

    RESULTS: Mean mortality of P. argentipes 24 h after exposure in tube tests was 22.6% for DDT and ≥ 98% for other insecticide-impregnated papers tested.

    CONCLUSION: Phlebotomus argentipes continues to be highly resistant to DDT with no reversal of resistance after DDT's withdrawal from IRS. P. argentipes was fully susceptible to pyrethroid, organophosphate and carbamate insecticides tested. Regular monitoring is warranted for insecticide resistance management in sandfly vectors.

    Matched MeSH terms: Insect Vectors/drug effects*
  6. Goh XT, Lim YAL, Lee PC, Nissapatorn V, Chua KH
    Mol Biochem Parasitol, 2021 07;244:111390.
    PMID: 34087264 DOI: 10.1016/j.molbiopara.2021.111390
    The present study aimed to examine the genetic diversity of human malaria parasites (i.e., P. falciparum, P. vivax and P. knowlesi) in Malaysia and southern Thailand targeting the 19-kDa C-terminal region of Merozoite Surface Protein-1 (MSP-119). This region is essential for the recognition and invasion of erythrocytes and it is considered one of the leading candidates for asexual blood stage vaccines. However, the genetic data of MSP-119 among human malaria parasites in Malaysia is limited and there is also a need to update the current sequence diversity of this gene region among the Thailand isolates. In this study, genomic DNA was extracted from 384 microscopy-positive blood samples collected from patients who attended the hospitals or clinics in Malaysia and malaria clinics in Thailand from the year 2008 to 2016. The MSP-119 was amplified using PCR followed by bidirectional sequencing. DNA sequences identified in the present study were subjected to Median-joining network analysis with sequences of MSP-119 obtained from GenBank. DNA sequence analysis revealed that PfMSP-119 of Malaysian and Thailand isolates was not genetically conserved as high number of haplotypes were detected and positive selection was prevalent in PfMSP-119, hence questioning its suitability to be used as a vaccine candidate. A novel haplotype (Q/TNG/L) was also detected in Thailand P. falciparum isolate. In contrast, PvMSP-119 was highly conserved, however for the first time, a non-synonymous substitution (A1657S) was reported among Malaysian isolates. As for PkMSP-119, the presence of purifying selection and low nucleotide diversity indicated that it might be a potential vaccine target for P. knowlesi.
    Matched MeSH terms: Insect Vectors/parasitology
  7. Izwan-Anas N, Ya'cob Z, Low VL, Lourdes EY, Ramli R, Bolongan G, et al.
    Acta Trop, 2021 Jun;218:105904.
    PMID: 33775626 DOI: 10.1016/j.actatropica.2021.105904
    Most female black flies in the genus Simulium are blood-sucking flies and they can cause various parasitic diseases in human and animal. A total of 94 species of black flies have been reported in Malaysia, however, their biting behavior and role as vector of infectious agents remain understudied. To fill in this knowledge gap, we attempted to survey adult black flies from field populations in Peninsular Malaysia. In a survey carried out in 2017 at Tasik Kenyir, Terengganu, three females were caught while attracted and landed on human skin. Further morphological and molecular analyses showed that the specimens were identical to Simulium (Gomphostilbia) aziruni Takaoka, Hashim & Chen of the Simulium gombakense species-group. This is the first report on a black fly species attracted to human in Malaysia which serves as a steppingstone towards in-depth studies for black flies in this region.
    Matched MeSH terms: Insect Vectors/classification
  8. Alharazi TH, Haouas N, Al-Mekhlafi HM
    BMC Infect Dis, 2021 Mar 17;21(1):269.
    PMID: 33731042 DOI: 10.1186/s12879-021-05965-4
    BACKGROUND: Cutaneous leishmaniasis (CL), a neglected tropical disease, represents a significant public health problem in many endemic countries including Yemen. The ongoing armed conflict that started in March 2015 has had a negative impact on the entire healthcare system as well as on infectious disease control programmes. Therefore, this cross-sectional study aimed to assess knowledge and attitude towards CL among rural endemic communities in southwestern Yemen.

    METHODS: Five hundred households in five areas of Shara'b district of Taiz governorate were randomly selected to participate in a quantitative survey. A pretested structured questionnaire was used to collect data on the sociodemographic characteristics of the participants, their knowledge and attitude towards CL and their knowledge on the sand fly vector.

    RESULTS: The analysis was conducted on a final sample of 466 individuals (62.7% males and 37.3% females) aged between 18 and 70 years. Among the participants, 21.5% were non-educated while 39.7 and 20.8% had completed secondary school and tertiary education, respectively. Although the participants were aware of CL, about three quarters (77.7%) of them had poor overall knowledge about disease transmission, clinical presentation, treatment, and prevention. Interestingly, approximately half of the participants (49.1%) were able to differentiate sand flies from other flies and mosquitoes. However, only 14.8% of the participants knew about the role of the phlebotomine sand fly in the transmission of CL. Only 36.6% believed that CL can be prevented and 49.6% had a negative attitude towards the disease. Univariate and multivariate analyses showed that age and gender were the significant determinants of knowledge about CL and the sand fly vector among the studied population.

    CONCLUSION: A poor level of knowledge about the different epidemiological aspects of CL was found among rural CL-endemic communities in Taiz. This factor, together with the major collapse of the healthcare infrastructure due to the ongoing civil war in Yemen, may be contributing to the continued endemicity of CL in the governorate. It is therefore recommended that health education on CL transmission and prevention should be provided to the targeted communities.

    Matched MeSH terms: Insect Vectors/physiology
  9. Younas M, Zou H, Laraib T, Rajpoot NA, Khan NA, Zaidi AA, et al.
    PLoS One, 2021;16(9):e0256449.
    PMID: 34529693 DOI: 10.1371/journal.pone.0256449
    Mungbean yellow mosaic virus (MYMV) is an important constraint in successful production of mungbean (Vigna radiata L.) in many countries, including Pakistan. The MYMV spreads by insect vector whitefly (Bemisia tabaci Gennadius). The use of resistant cultivars is the most effective management tactics for MYMV. Twenty mungbean varieties/lines were screened against insect vector of MYMV under field condition in the current study. Resistance levels for varieties/lines were assessed through visual scoring of typical disease symptoms. Furthermore, the impacts of two insecticides 'Imidacloprid' and 'Thiamethoxam' and two plant extracts, i.e., neem (Azadirachta indica), and Eucalyptus (Eucalyptus camaldulensis) were tested on the suppression of whitefly. Field screening indicated that none of the tested varieties/lines proved immune/highly resistant, while significant variations were recorded among varieties/lines for resistance level. All varieties/lines were systemically infected with MYMV. The varieties 'AARI-2006' and 'Mung-14043' were considered as resistant to MYMV based on visual symptoms and the lowest vector population. These varieties were followed by 'NM-2006' and 'NL-31', which proved as moderately resistant to MYMV. All remaining varieties/lines were grouped as moderately to highly susceptible to MYMV based on visual symptoms' scoring. These results revealed that existing mungbean germplasm do not possess high resistance level MYMV. However, the lines showing higher resistance in the current study must be exploited in breeding programs for the development of resistant mungbean varieties/lines against MYMV. Imidacloprid proved as the most effective insecticide at all concentrations to manage whitefly population. Therefore, use of the varieties with higher resistance level and spraying Imidacloprid could lower the incidence of MYMV.
    Matched MeSH terms: Insect Vectors/drug effects*
  10. Castellanos-Sánchez P, Falconi-Agapito F, Pariona N, Paredes-Esquivel C
    Trop Biomed, 2020 Dec 01;37(4):864-870.
    PMID: 33612739 DOI: 10.47665/tb.37.4.864
    Chagas disease is endemic to the Americas and is transmitted by blood-feeding kissing bugs. We evaluated the insecticidal potential of a fungus (Beauveria bassiana strain Pr-11) against Triatoma infestans, an important vector in South America. This fungal species was isolated from a locust (Schistocerca piceifrons) that inhabits the Central Andes region of Peru. Ten days post inoculation, this strain induced high insect mortality (97%) at low fungal concentrations (2 × 107 conidia/ml) at 70% relative humidity. The Pr-11 strain outperformed reference strain CCBLE-216 B. bassiana, provided by the Peruvian Ministry of Agriculture. Our results are consistent with previous reports on the virulence of this fungal strain against other insect pests. This is the first study to evaluate an orthopteran-isolated B. bassiana to control Chagas disease vectors. We conclude that strain Beauveria bassiana Pr-11 is effective against Triatoma infestans, resulting in a promising tool to control Chagas disease in Peru and may be used in integrated vector control programs.
    Matched MeSH terms: Insect Vectors/microbiology
  11. Tabasi M, Alesheikh AA, Sofizadeh A, Saeidian B, Pradhan B, AlAmri A
    Parasit Vectors, 2020 Nov 11;13(1):572.
    PMID: 33176858 DOI: 10.1186/s13071-020-04447-x
    BACKGROUND: Zoonotic cutaneous leishmaniasis (ZCL) is a neglected tropical disease worldwide, especially the Middle East. Although previous works attempt to model the ZCL spread using various environmental factors, the interactions between vectors (Phlebotomus papatasi), reservoir hosts, humans, and the environment can affect its spread. Considering all of these aspects is not a trivial task.

    METHODS: An agent-based model (ABM) is a relatively new approach that provides a framework for analyzing the heterogeneity of the interactions, along with biological and environmental factors in such complex systems. The objective of this research is to design and develop an ABM that uses Geospatial Information System (GIS) capabilities, biological behaviors of vectors and reservoir hosts, and an improved Susceptible-Exposed-Infected-Recovered (SEIR) epidemic model to explore the spread of ZCL. Various scenarios were implemented to analyze the future ZCL spreads in different parts of Maraveh Tappeh County, in the northeast region of Golestan Province in northeastern Iran, with alternative socio-ecological conditions.

    RESULTS: The results confirmed that the spread of the disease arises principally in the desert, low altitude areas, and riverside population centers. The outcomes also showed that the restricting movement of humans reduces the severity of the transmission. Moreover, the spread of ZCL has a particular temporal pattern, since the most prevalent cases occurred in the fall. The evaluation test also showed the similarity between the results and the reported spatiotemporal trends.

    CONCLUSIONS: This study demonstrates the capability and efficiency of ABM to model and predict the spread of ZCL. The results of the presented approach can be considered as a guide for public health management and controlling the vector population .

    Matched MeSH terms: Insect Vectors/parasitology
  12. Nguyen VL, Colella V, Greco G, Fang F, Nurcahyo W, Hadi UK, et al.
    Parasit Vectors, 2020 Aug 15;13(1):420.
    PMID: 32799914 DOI: 10.1186/s13071-020-04288-8
    BACKGROUND: Ticks and fleas are considered amongst the most important arthropod vectors of medical and veterinary concern due to their ability to transmit pathogens to a range of animal species including dogs, cats and humans. By sharing a common environment with humans, companion animal-associated parasitic arthropods may potentially transmit zoonotic vector-borne pathogens (VBPs). This study aimed to molecularly detect pathogens from ticks and fleas from companion dogs and cats in East and Southeast Asia.

    METHODS: A total of 392 ticks and 248 fleas were collected from 401 infested animals (i.e. 271 dogs and 130 cats) from China, Taiwan, Indonesia, Malaysia, Singapore, Thailand, the Philippines and Vietnam, and molecularly screened for the presence of pathogens. Ticks were tested for Rickettsia spp., Anaplasma spp., Ehrlichia spp., Babesia spp. and Hepatozoon spp. while fleas were screened for the presence of Rickettsia spp. and Bartonella spp.

    RESULT: Of the 392 ticks tested, 37 (9.4%) scored positive for at least one pathogen with Hepatozoon canis being the most prevalent (5.4%), followed by Ehrlichia canis (1.8%), Babesia vogeli (1%), Anaplasma platys (0.8%) and Rickettsia spp. (1%) [including Rickettsia sp. (0.5%), Rickettsia asembonensis (0.3%) and Rickettsia felis (0.3%)]. Out of 248 fleas tested, 106 (42.7%) were harboring at least one pathogen with R. felis being the most common (19.4%), followed by Bartonella spp. (16.5%), Rickettsia asembonensis (10.9%) and "Candidatus Rickettsia senegalensis" (0.4%). Furthermore, 35 Rhipicephalus sanguineus ticks were subjected to phylogenetic analysis, of which 34 ticks belonged to the tropical and only one belonged to the temperate lineage (Rh. sanguineus (sensu stricto)).

    CONCLUSION: Our data reveals the circulation of different VBPs in ticks and fleas of dogs and cats from Asia, including zoonotic agents, which may represent a potential risk to animal and human health.

    Matched MeSH terms: Insect Vectors/microbiology; Insect Vectors/parasitology
  13. Kittiwattanawong K, Ponlawat A, Boonrotpong S, Nanakorn N, Kongchouy N, Moonmake S, et al.
    Trop Biomed, 2020 Jun 01;37(2):397-408.
    PMID: 33612809
    The Anopheles dirus mosquito is a primary malaria vector that transmits many species of Plasmodium parasites in Thailand and is widely spread across its geographic area. In the current study, the levels of expression of the suppressor of cytokine signaling (SOCS) gene in An. dirus mosquitoes infected with P. vivax were examined. The level of the gene's expression determined by mRNA extraction in An. dirus females (n=2,400) was studied at different times (0, 12, 24, 36, and 48 h after feeding), with different types of blood feeding (non-feeding, parasite-negative blood feeding, parasite-positive blood feeding) and in different parts of the body of mosquito samples (thorax and abdomen). The datasets were analyzed based on their relative expression ratio by the 2-ΔΔCT method and were tested for significant differences with ANOVA. The results showed that the An. dirus SOCS gene was stimulated in the abdomen 12 h and 24 h after blood feeding about three times more highly than in unfed females, with the difference being significant. At 24 h after P. vivax-infected blood feeding, the SOCS gene in the abdomen was expressed more highly than 24 h after parasite-negative blood feeding and expression was almost 36 times higher than in the control group who were not fed blood. However, in the thorax at all times after feeding and non-feeding, there was no expression of the SOCS gene. Therefore, the SOCS gene in An. dirus was most highly expressed 24 h post-feeding with a P. vivax-infected bloodmeal, which indicates that the SOCS gene in the major malaria vector in Thailand plays an important role in its immune system and its response to P. vivax infection.
    Matched MeSH terms: Insect Vectors/parasitology
  14. Onah IE, Ubachukwu PO, Eyo JE
    Trop Biomed, 2020 Mar 01;37(1):174-185.
    PMID: 33612728
    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.
    Matched MeSH terms: Insect Vectors/parasitology
  15. Nazni WA, Hoffmann AA, NoorAfizah A, Cheong YL, Mancini MV, Golding N, et al.
    Curr Biol, 2019 Dec 16;29(24):4241-4248.e5.
    PMID: 31761702 DOI: 10.1016/j.cub.2019.11.007
    Dengue has enormous health impacts globally. A novel approach to decrease dengue incidence involves the introduction of Wolbachia endosymbionts that block dengue virus transmission into populations of the primary vector mosquito, Aedes aegypti. The wMel Wolbachia strain has previously been trialed in open releases of Ae. aegypti; however, the wAlbB strain has been shown to maintain higher density than wMel at high larval rearing temperatures. Releases of Ae. aegypti mosquitoes carrying wAlbB were carried out in 6 diverse sites in greater Kuala Lumpur, Malaysia, with high endemic dengue transmission. The strain was successfully established and maintained at very high population frequency at some sites or persisted with additional releases following fluctuations at other sites. Based on passive case monitoring, reduced human dengue incidence was observed in the release sites when compared to control sites. The wAlbB strain of Wolbachia provides a promising option as a tool for dengue control, particularly in very hot climates.
    Matched MeSH terms: Insect Vectors
  16. Pramual P, Bunchom N, Saijuntha W, Tada I, Suganuma N, Agatsuma T
    Trop Biomed, 2019 Dec 01;36(4):938-957.
    PMID: 33597465
    Genetic variation based on mitochondrial cytochrome c oxidase I (COI) and II (COII) sequences was investigated for three black fly nominal species, Simulium metallicum Bellardi complex, S. callidum Dyar and Shannon, and S. ochraceum Walker complex, which are vectors of human onchocerciasis from Guatemala. High levels of genetic diversity were found in S. metallicum complex and S. ochraceum complex with maximum intraspecific genetic divergences of 11.39% and 4.25%, respectively. Levels of genetic diversity of these nominal species are consistent with species status for both of them as they are cytologically complexes of species. Phylogenetic analyses revealed that the S. metallicum complex from Guatemala divided into three distinct clades, two with members of this species from several Central and South American countries and another exclusively from Mexico. The Simulium ochraceum complex from Guatemala formed a clade with members of this species from Mexico and Costa Rica while those from Ecuador and Colombia formed another distinct clade. Very low diversity in S. callidum was found for both genes with maximum intraspecific genetic divergence of 0.68% for COI and 0.88% for COII. Low genetic diversity in S. callidum might be a consequence of the result being informative of only recent population history of the species.
    Matched MeSH terms: Insect Vectors/genetics; Insect Vectors/parasitology
  17. Fornace KM, Alexander N, Abidin TR, Brock PM, Chua TH, Vythilingam I, et al.
    Elife, 2019 10 22;8.
    PMID: 31638575 DOI: 10.7554/eLife.47602
    Human movement into insect vector and wildlife reservoir habitats determines zoonotic disease risks; however, few data are available to quantify the impact of land use on pathogen transmission. Here, we utilise GPS tracking devices and novel applications of ecological methods to develop fine-scale models of human space use relative to land cover to assess exposure to the zoonotic malaria Plasmodium knowlesi in Malaysian Borneo. Combining data with spatially explicit models of mosquito biting rates, we demonstrate the role of individual heterogeneities in local space use in disease exposure. At a community level, our data indicate that areas close to both secondary forest and houses have the highest probability of human P. knowlesi exposure, providing quantitative evidence for the importance of ecotones. Despite higher biting rates in forests, incorporating human movement and space use into exposure estimates illustrates the importance of intensified interactions between pathogens, insect vectors and people around habitat edges.
    Matched MeSH terms: Insect Vectors
  18. Zaw MT, Lin Z
    J Microbiol Immunol Infect, 2019 Oct;52(5):679-684.
    PMID: 31320238 DOI: 10.1016/j.jmii.2019.05.012
    Plasmodium knowlesi is now regarded as the fifth malaria parasite causing human malaria as it is widely distributed in South-East Asian countries especially east Malaysia where two Malaysian states namely Sabah and Sarawak are situated. In 2004, Polymerase Chain Reaction (PCR) was applied for diagnosing knowlesi malaria in the Kapit Division of Sarawak, Malaysia, so that human P. knowlesi infections could be detected correctly while blood film microscopy diagnosed incorrectly as Plasmodium malariae. This parasite is transmitted from simian hosts to humans via Anopheles vectors. Indonesia is the another country in South East Asia where knowlesi malaria is moderately prevalent. In the last decade, Sarawak and Sabah, the two states of east Malaysia became the target of P. knowlesi research due to prevalence of cases with occasional fatal infections. The host species of P. knowlesi are three macaque species namely Macaca fascicularis, Macaca nemestrina and Macaca leonina while the vector species are the Leucosphyrus Complex and the Dirus Complex of the Leucophyrus Group of Anopheles mosquitoes. Rapid diagnostic tests (RDT) are non-existent for knowlesi malaria although timely treatment is necessary for preventing complications, fatality and drug resistance. Development of RDT is essential in dealing with P. knowlesi infections in poor rural healthcare services. Genetic studies of the parasite on possibility of human-to-human transmission of P. knowlesi were recommended for further studies.
    Matched MeSH terms: Insect Vectors
  19. Shigeharu Sato, Tomonori Hoshi, Bumpei Tojo, Samson Yodot, Joni Jain
    MyJurnal
    Introduction: Collecting mosquitoes is essential for research in mosquito-borne diseases, but the light traps used for that purpose are expensive and often difficult to obtain around research fields. We designed a new 3D-printable mosquito light trap that can be made inexpensively anywhere where electricity is available (Hoshi et al, Scientific Reports, in press). In this study, we produced that trap in Sabah and demonstrated its usefulness in the field. Meth-ods: With a 3D printer, the main parts of the trap - body, lid, lamp stand and collection box - were printed in Kota Kinabalu using black polylactic acid (PLA) filaments purchased online. All other parts such as the computer fan and batteries were commercially available at local shops in Sabah. The parts were assembled into the complete units at Universiti Malaysia Sabah’s Rural Medical Education Centre (RMEC) in Sikuati, Kudat. Demonstration was performed at two sites in the Kudat district: RMEC campus and the premises of a local farm in Kampung Paradason. Results: The 3D traps collected 6 and 7 different species of mosquitoes at RMEC and Paradason sites, respectively. The numbers of mosquito species collected by the commercially-available CDC model-512 traps in parallel experiments were 2 (RMEC) and 10 (Paradason). The species collected by the 3D traps included Aedes albopictus (vector transmitting Dengue virus), Anopheles barbumbrosus (malaria), Culex quinquefasciatus (Wuchereria bancrofti, avian malaria, and arboviruses including Japanese encephalitis and Zika viruses) and Mansonia indiana (Brugia malayi). Conclu-sion: The 3D light trap which was produced in Sabah demonstrated its usefulness in the field tests performed in the Kudat district. This model can be used as an alternative to the rather expensive commercial light traps to collect the vector insects transmitting mosquito-borne diseases such as malaria, dengue, Japanese encephalitis, Zika fever and filariasis.
    Matched MeSH terms: Insect Vectors
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links