Anopheles flavirostris incriminated as a vector of malaria and Bancroftian filariasis in Banggi Island, Sabah, Malaysia (original) (raw)
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2016
Entomological investigations were conducted in four remaining lymphatic filariasis endemic provinces of Panay Island, The Philippines to determine mosquito species present in these areas and to identify host preference and biting activity of Aedes (Finlaya) poicilius Theobald, primary vector of nocturnal periodic Wuchereria bancrofti in The Philippines. Sampling techniques targeted nocturnally active mosquito species using a carabao-baited trap (CBT) and human-landing collection (HLC), the latter taking place from 06:00 to 12:00 pm. A total of 25,536 mosquitoes comprising 42 species and 7 genera were collected from CBT, whilst HLC acquired 6,486 mosquitoes comprising 28 species and 5 genera. Three known or potential vectors of human filarial were collected, namely, Aedes poicilius, Culex quinquefasciatus and Mansonia uniformis. The peak landing (biting) activity for Ae. poicilius was between 09:00 and 11:00 pm. Comparisons between CBT and HLC yields showed this species to be more zo...
Larval Ecology of Anopheles Mosquitoes in Kudat, Sabah
Borneo Journal of Medical Sciences (BJMS), 2021
The emergence of human Plasmodium knowlesi malaria appeared to have been precipitated by the displacement of the natural environment of macaques and Anopheles mosquitoes resulting from deforestation and land-use changes in Malaysia. A longitudinal survey of larval habitats was conducted from May 2015 to April 2016 in the District of Kudat, Sabah to better understand how these changes have affected mosquitoes across six land use categories. Larvae were collected by dipping and reared in the laboratory for the identification of adults. Five anopheline and three culicine species were present: Anopheles balabacensis, An. barbirostris, An. lesteri, An. borneensis, An. umbrosus, Aedes albopictus, Culex gelidus, and Toxorhynchites sp. An. balabacensis was found in all six land-use types. Biodiversity by genera was high in all land-use types. The relative importance of land use types and larval habitats as sources of potential vectors was analyzed by the Kruskal-Wallis H test by ranks. In d...
Malaria and filaria infection rates were determined for anopheline mosquitoes collected whilst biting and resting in village houses in Papua New Guinea. The number of anophelines infected with both parasites was greater than expected from the infection rates of each parasite and this difference was significant in resting collections. The excess of multiply infected mosquitoes is probably a result of a vector population composed of individuals with differing numbers of opportunities to become infected. Malaria-positive Anopheles punctulatus from resting catches had a significantly greater number of Stage 3 Wuchereria bancrofti larvae than malaria-negative mosquitoes. However, multiply infected mosquitoes appear to suffer greater mortality than non-infected or singly infected mosquitoes when the filarial worm reaches the third stage. Any potential increase in transmission resulting from multiple infections is thereby offset by a greater mortality rate in these mosquitoes.
Veterinary World, 2020
Background and Aim: Lymphatic filariasis, also known as elephantiasis, still remains a problem in Indonesia. The primary causative species of this disease are the filarial worms Wuchereria bancrofti and Brugia spp. This study was conducted to identify the diversity of species and behavior of mosquitoes and to determine the mosquitoes that could be potential vectors of filariasis. Materials and Methods: Mosquito samples derived from Hulu Sungai Utara (HSU) district in the 2017 multicenter study conducted in Indonesia were used in this cross-sectional study. The diversity of mosquito species was analyzed using the Shannon–Wiener diversity index. Mosquitoes were identified based on their species, and their DNA was isolated by polymerase chain reaction (PCR). Transcription-insulated isothermal PCR method was used to detect microfilariae/filaria larvae in the mosquitoes. Results: Biodiversity was found in 14 species of mosquitoes belonging to five genera. The maximum number of mosquitoes was recorded from the species Mansonia dives, Culex vishnui, Culex quinquefasciatus, and Mansonia uniformis. W. bancrofti infection was detected in M. uniformis at an infectivity rate of 0.3% (n=311). Conclusion: To the best of our knowledge, this is the first report of M. uniformis species as a vector of W. bancrofti in HSU district, Indonesia. More efficient and accurate studies are required to aid in the lymphatic filariasis elimination programs in this subregion.
Acta Tropica, 2005
A study was carried out from July 2001 until January 2003 in the Kinabatangan area of Sabah, part of Borneo island, where malaria used to be mesoendemic. Vector surveys determined that Plasmodium falciparum was the predominant species and Anopheles balabacensis the primary vector. Malaria cases have dropped drastically over the years but P. falciparum is still predominant. In the present study, Anopheles donaldi was the predominant species and was positive for sporozoites. Although An. balabacensis was present, none were infective. An. donaldi bite more outdoors than indoors and have a peak biting time from 18:00 to 19:00 h when most people are still out of their homes. An integrated malaria control programme along with area development has helped in the control of malaria and its vector.
Entomologic investigation of Plasmodium knowlesi vectors in Kuala Lipis, Pahang, Malaysia
Malaria Journal, 2012
BACKGROUND: The first natural infection of Plasmodium knowlesi in humans was recorded in 1965 in peninsular Malaysia. Extensive research was then conducted and it was postulated that it was a rare incident and that simian malaria will not be easily transmitted to humans. However, at the turn of the 21st century, knowlesi malaria was prevalent throughout Southeast Asia and is life threatening. Thus, a longitudinal study was initiated to determine the vectors, their seasonal variation and preference to humans and macaques. METHODS: Monthly mosquito collections were carried out in Kuala Lipis, Pahang, peninsular Malaysia, using human-landing collection and monkey-baited traps at ground and canopy levels. All mosquitoes were identified and all anopheline mosquitoes were dissected and the gut and gland examined for oocysts and sporozoites. Nested polymerase chain reaction (PCR) was conducted on positive samples, followed by sequencing of the csp gene. RESULTS AND DISCUSSION: Anopheles cracens was the predominant mosquito biting humans as well as the macaques. It comprised 63.2% of the total collection and was the only species positive for sporozoites of P. knowlesi. It was exophagic and did not enter houses. Besides An. cracens, Anopheles kochi was also found in the monkey-bait trap. Both species preferred to bite monkeys at ground level compared to canopy. CONCLUSION: Anopheles cracens, which belongs to the Dirus complex, Leucosphyrus subgroup, Leucosphyrus group of mosquitoes, has been confirmed to be the only vector for this site from Pahang during this study. It was the predominant mosquito at the study sites and with deforestation humans and villages are entering deeper in the forests, and nearer to the mosquitoes and macacques. The close association of humans with macaques and mosquitoes has led to zoonotic transmission of malaria.
Infection, Genetics and Evolution, 2010
Malaria and lymphatic filariasis are two of the most common mosquito-borne parasitic diseases worldwide which can occur as concomitant human infections while also sharing common mosquito vectors. This review presents the most recent available information on the co-transmission of human Plasmodium species and Wuchereria bancrofti by Anopheles mosquitoes. Important biological and epidemiological aspects are also described including the lifecycle of each parasite species and their specificities, the geographical biodiversity of each pathogen and their vectors where the parasites are coendemic, and biological, environmental and climatic determinants influencing transmission. The cotransmission of each disease is illustrated from both a global perspective and a country level using Thailand as a study case. Different diagnostic methods are provided for the detection of the parasites in biological samples ranging from traditional to more recent molecular methods, including methodologies employing concomitant detection assays of W. bancrofti and Plasmodium spp. parasites. The relevant issues of combined malaria and Bancroftian filariasis control strategies are reviewed and discussed.
Anopheles Barbirostris/campestris as a probable vector of malaria in Aranyaprathet, Sa Kaeo Province
Southeast Asian Journal of Tropical Medicine and Public Health, 2001
As a result of dramatic increase in malaria cases in Sa Kaeo Province from 666 cases in 1995 to 4,381 in 1997, a brief entomological study was carried out during January 1998 to December,1999 in Pa Rai subdistrict where most malaria cases were reported. Of fourteen species of mosquitos found, only Anopheles barbirostris group was the most abundant species throughout the year. Adult identification was not able to confirm species within An. barbirostris group, particularly between An. barbirostris and An. campestris because of morphological resemblance. Therefore, the barbirostris group captured in this study is reported to be either An. barbirostris or An. campesrris. ' The seasonal prevalence of barbirostris/campestris was bimodal in distribution (September and November) and coincided well with malaria occurrence in this area. Human landing collections revealed high adult densities with 20 biteslperson-night for mean indoor density and 53.5 biteslperson-night for mean outdoor density. The biting peak was during 21.00-24.00 hours. Among 223 barbirostris/campestris dissected for oocysts and sporozoites only one gut from the outdoor collection in November was infected with oocysts. There were no sporozoites detected in salivary glands of all mosquitos collected. ' This appears to indicate that in the absence of major vectors local species may serve as potential transmitters of malaria in Thailand.
Malaria Journal, 2008
Background A large focus of human infections with Plasmodium knowlesi, a simian parasite naturally found in long-tailed and pig-tailed macaques was discovered in the Kapit Division of Sarawak, Malaysian Borneo. A study was initiated to identify the vectors of malaria, to elucidate where transmission is taking place and to understand the bionomics of the vectors in Kapit. Methods Three different ecological sites in the forest, farm and longhouse in the Kapit district were selected for the study. Mosquitoes were collected by human landing collection at all sites and at the forest also by monkey-baited-traps situated on three different levels. All mosquitoes were identified and salivary glands and midguts of anopheline mosquitoes were dissected to determine the presence of malaria parasites. Results and Discussions Over an 11-month period, a total of 2,504 Anopheles mosquitoes comprising 12 species were caught; 1,035 at the farm, 774 at the forest and 425 at the longhouse. Anopheles latens (62.3%) and Anopheles watsonii (30.6%) were the predominant species caught in the forested ecotypes, while in the farm Anopheles donaldi (49.9%) and An. latens (35.6%) predominated. In the long house, An. latens (29.6%) and An. donaldi (22.8%) were the major Anopheline species. However, An. latens was the only mosquito positive for sporozoites and it was found to be attracted to both human and monkey hosts. In monkey-baited net traps, it preferred to bite monkeys at the canopy level than at ground level. An. latens was found biting early as 18.00 hours. Conclusion Anopheles latens is the main vector for P. knowlesi malaria parasites in the Kapit District of Sarawak, Malaysian Borneo. The study underscores the relationship between ecology, abundance and bionomics of anopheline fauna. The simio-anthropophagic and acrodendrophilic behaviour of An. latens makes it an efficient vector for the transmission of P. knowlesi parasites to both human and monkey hosts. Go to: Background Malaria parasites in Peninsular Malaysian monkeys were first reported in 1908 [1], but only gained prominence in the 1960's after the accidental discovery [2] that Plasmodium cynomolgi could be transmitted to humans via mosquito bites in the laboratory. This stimulated interest at a time when the Malaria Eradication Programme was initiated by the World Health Organization [3] and it was important to determine if malaria was a zoonosis. Therefore, extensive studies were carried out in Peninsular Malaysia to determine the distribution, prevalence and species of malaria parasites in monkeys and apes and the natural vectors of monkey malaria parasites [4-7]. Instead of uncovering human cynomolgi malaria infections, Plasmodium knowlesi was the first simian malaria parasite found to be infecting humans in nature. The first case was reported in 1965 from the state of Pahang [8], Peninsular Malaysia, followed by a second case five years later acquired from Johore, Peninsular Malaysia [9]. It was postulated that P. knowlesi could be transmitted from monkeys to man and laboratory studies proved that it was possible [10]. However, a large scale study that was initiated in Pahang to investigate whether malaria was a zoonosis, by a group of American and local researchers based at the Institute for Medical Research in Kuala Lumpur, Peninsular Malaysia, concluded that simian malaria in humans was an extremely rare event [11,12]. This was based on their studies in which they collected blood samples from more than 1,100 local residents, pooled the samples and injected them into rhesus monkeys and none of the monkeys contracted malaria. However, in 2004 a large focus of human P. knowlesi infection was reported in the Kapit Division of Sarawak [13]. In that study 71.6% (101/141) of human malaria cases at Kapit Hospital which had been identified by microscopy as single Plasmodium malariae infections were actually P. knowlesi and other non-P. malariae species by nested polymerase chain reaction (PCR) assays. Plasmodium knowlesi is naturally found in long-tailed macaques (Macaca fascicularis), pig-tailed macaques (Macaca nemestrina) [14] and banded leaf monkeys (Presbytis malalophos) [15,16]. Since transmission of this zoonotic parasite to humans is occurring in the Kapit Division of Sarawak, Malaysian Borneo, it is important to identify the vectors so that appropriate measures can be planned and initiated to control the spread of simian malaria in humans. Numerous studies on vectors of human malaria have been carried out in Sarawak [17-20] but none of these have been undertaken in the Kapit District of Sarawak. Several anopheline species incriminated or suspected to transmit monkey malaria parasites in Peninsular Malaysia, such as Anopheles latens, Anopheles balabacensis are also present in Sarawak [21]. Hence, the vectorial status of the anopheline species present in the Kapit Division needs to be ascertained in order to determine if they are competent vectors of simian malaria parasites. Furthermore, the epidemiological data of P. knowlesi infection in humans revealed that infections occur primarily in adults and no clustering of cases occurred within communities that live in communal longhouses, which suggests transmission of P. knowlesi to humans occurred away from the vicinity of the longhouses [13]. Thus the objectives of this study were to determine the vectors of P. knowlesi and other simian malaria parasites in the Kapit Division of Sarawak; and to study the dynamics of these vectors in different ecological sites in order to elucidate the most likely place where transmission was taking place. Preliminary results of this study were reported where An. latens was incriminated as the vector for P. knowlesi [22]. Here detailed results of this eleven-month study on vectors of malaria and their bionomics in the Kapit district of Sarawak, Malaysian Borneo is presented.
Biodiversitas Journal of Biological Diversity
A study on the diversity, dominance and behavior of mosquitoes was done in the two filariasis endemic areas in Bogor District, West Java, Indonesia. The objectives of this study were to determine the diversity, dominance and behavior of mosquitoes and their importance as vectors of filariasis in two endemic areas in Bogor District, namely Tamansari Village (rural) and Cimanggis Village (urban). This research was carried out from September 2019 to February 2020. Mosquitoes were collected from 6.00 pm to 6.00 am, twice a month in each village, by using the bare leg collection technique. The collected mosquitoes were identified and analyzed. Filaria detection was carried out by dissecting technique and polymerase chain reaction (PCR). The result indicated eight (8) species of mosquitoes in the rural area (Tamansari village), i.e., Culex quinquefasciatus, Aedes aegypti, Cx. vishnui, Cx. tritaeniorhynchus, Armigeres kesseli, Ar. subalbatus, Ae. albopictus, Mansonia annulata. On the other hand, there were six (6) species found in the urban area (Cimanggis village), i.e., Cx. quinquefasciatus, Ae. aegypti, Ar. kesseli, Ar. subalbatus, Cx. vishnui, Cx. tritaeniorhynchus and Cx. quinquefasciatus were found to be the most dominant in Tamansari village (90.46) and also in Cimanggis Village (95.67). Based on the analysis showed that the mosquito diversity index was low in both the Tamansari village (H': 0.444) and the Cimanggis village (H': 0.238). In general, mosquito-biting behavior prefers to suck blood indoors (anthropophilic) with a peak density in the range of 23.00-04.00. The results of filarial detection using dissecting technique and PCR methods against mosquitoes caught in Tamansari Village and Cimanggis Village did not find any L3 larvae and microfilariae in the examined mosquitoes. Culex quinquefasciatus was found to be very potential as the main vector for the spread of filariasis both in rural and urban areas of endemic filariasis of Bogor District, Indonesia.