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Fulltext Lymphatic filariasis in Peninsular Malaysia: a cross-sectional survey of the knowledge, attitudes, and practices of residents

Al-Abd NM, Nor ZM, Ahmed A, Al-Adhroey AH, Mansor M, Kassim M

Parasit Vectors, 2014;7:545.
PMID: 25428558 DOI: 10.1186/s13071-014-0545-z

Lymphatic filariasis (LF) is a major cause of permanent disability in many tropical and sub-tropical countries of the world. Malaysia is one of the countries in which LF is an endemic disease. Five rounds of the mass drug administration (MDA) program have been conducted in Malaysia as part of the Global Program to Eliminate Lymphatic Filariasis (GPELF) by year 2020. This study investigated the level of awareness of LF and the MDA program in a population living in an endemic area of the country.

Matched MeSH terms: Culicidae/parasitology
Environmental variables associated with immature stage habitats of culicidae collected in aboriginal villages in Pahang, Malaysia

Ali WN, Ahmad R, Nor ZM, Ismail Z, Ibrahim MN, Hadi AA, et al.

Southeast Asian J. Trop. Med. Public Health, 2012 Nov;43(6):1387-99.
PMID: 23413702

Many of the most widely spread vector-borne diseases are water related, in that the mosquito vectors concerned breed or pass part of their lifecycle in or close to water. A major reason for the study of mosquito larval ecology is to gather information on environmental variables that may determine the species of mosquitoes and the distribution of larvae in the breeding habitats. Larval surveillance studies were conducted six times between May 2008 and October 2009 in Pos Lenjang, Kuala Lipis, Pahang. Twelve environmental variables were recorded for each sampling site, and samples of mosquito larvae were collected. Larval survey studies showed that anopheline and culicine larvae were collected from 79 and 67 breeding sites, respectively. All breeding sites were classified into nine habitat groups. Culicine larvae were found in all habitat groups, suggesting that they are very versatile and highly adaptable to different types of environment. Rock pools or water pockets with clear water formed on the bank of rivers and waterfalls were the most common habitats associated with An. maculatus. Environmental variables influence the suitability of aquatic habitats for anopheline and culicine larvae, but not significantly associated with the occurrence of both larvae genera (p>0.05). This study provides information on mosquito ecology in relation to breeding habitats that will be useful in designing and implementing larval control operations.

Matched MeSH terms: Culicidae/parasitology
Fulltext An update on the mosquito fauna and mosquito-borne diseases distribution in Cameroon

Bamou R, Mayi MPA, Djiappi-Tchamen B, Nana-Ndjangwo SM, Nchoutpouen E, Cornel AJ, et al.

Parasit Vectors, 2021 Oct 11;14(1):527.
PMID: 34635176 DOI: 10.1186/s13071-021-04950-9

The expansion of mosquito-borne diseases such as dengue, yellow fever, and chikungunya in the past 15 years has ignited the need for active surveillance of common and neglected mosquito-borne infectious diseases. The surveillance should be designed to detect diseases and to provide relevant field-based data for developing and implementing effective control measures to prevent outbreaks before significant public health consequences can occur. Mosquitoes are important vectors of human and animal pathogens, and knowledge on their biodiversity and distribution in the Afrotropical region is needed for the development of evidence-based vector control strategies. Following a comprehensive literature search, an inventory of the diversity and distribution of mosquitoes as well as the different mosquito-borne diseases found in Cameroon was made. A total of 290 publications/reports and the mosquito catalogue website were consulted for the review. To date, about 307 species, four subspecies and one putative new species of Culicidae, comprising 60 species and one putative new species of Anopheles, 67 species and two subspecies of Culex, 77 species and one subspecies of Aedes, 31 species and one subspecies of Eretmapodites, two Mansonia, eight Coquillettidia, and 62 species with unknown medical and veterinary importance (Toxorhynchites, Uranotaenia, Mimomyia, Malaya, Hodgesia, Ficalbia, Orthopodomyia, Aedeomyia, and Culiseta and Lutzia) have been collected in Cameroon. Multiple mosquito species implicated in the transmission of pathogens within Anopheles, Culex, Aedes, Eretmapodites, Mansonia, and Coquillettidia have been reported in Cameroon. Furthermore, the presence of 26 human and zoonotic arboviral diseases, one helminthic disease, and two protozoal diseases has been reported. Information on the bionomics, taxonomy, and distribution of mosquito species will be useful for the development of integrated vector management programmes for the surveillance and elimination of mosquito-borne diseases in Cameroon.

Matched MeSH terms: Culicidae/parasitology
Operational issues in the control of the vectors of Brugia

Chang MS

Ann Trop Med Parasitol, 2002 Dec;96 Suppl 2:S71-6.
PMID: 12625920

An estimated 13 million people in the Oriental Region have brugian filariasis. The filarial parasites that cause this disease exist in periodic and sub-periodic forms and are transmitted by four genera of mosquito: Anopheles, Mansonia and, less frequently, Coquillettidia and Ochlerotatus. In most endemic countries, control of the disease has been entirely based on chemotherapy, although house-spraying and use of insecticide-treated bednets can be quite effective against the vectors of nocturnally periodic Brugia malayi and B. timori. The vector-control methods that may be applied against the Mansonia mosquitoes that transmit the parasites causing sub-periodic brugian filariasis are reviewed here. Most of the conventional methods for controlling the immature, aquatic stages of mosquitoes have proved unsatisfactory against Mansonia. The reason is that, unlike the those of other genera, the larvae and pupae of Mansonia spp. are relatively immobile and obtain air not at the water surface but from the underwater roots, stems and leaves of floating plants to which the larvae and pupae attach. Removal of host plants can be very effective in reducing Mansonia productivity, whereas large-scale use of herbicides is restricted by the potential adverse effects on the ecosystem. Environmental management in water-development projects remains the best option.

Matched MeSH terms: Culicidae/parasitology*
Control of Mansonia mosquitos, vectors of brugian filariasis in Sarawak, Malaysia

Chang MS, Chan KL, Ho BC

Southeast Asian J. Trop. Med. Public Health, 1993;24 Suppl 2:93-104.
PMID: 7973956

Two field trials in the control of subperiodic brugian filariasis vectors, mainly Mansonia bonneae and Mansonia dives were carried out in Sarawak, East Malaysia. In the first trial, malathion ultra-low volume (ULV) spray was used to control the Mansonia mosquitos in two filariasis endemic villages. Six spray rounds were applied at biweekly intervals at Kampung Rasau and two spray rounds were applied at monthly intervals in Kampung Triboh. ULV malathion spray reduced biting Ma. bonneae population for 3 days after spraying. The biting density decreased to 50% of the pre-treatment level by the 12th - 13th day and reached the pre-treatment level by the 24th - 25th day. Contact bioassay tests on caged Mansonia mosquitos revealed considerable penetration of the malathion aerosol indoors and relatively adequate coverage outdoors. The estimated number of bites per case per day was 1.09 to 4 times less in the sprayed kampung than in an unsprayed control kampung. The parous and daily survival rates of Mansonia mosquitos were not significantly affected by the spraying. In a second trial, chemotherapy with diethylcarbamazine citrate (DEC) was combined with vector control through indoor residual spraying in Kampung Ampungan. The results were compared with the use of only DEC mass treatment in Kampung Sebangkoi and Kampung Sebamban. The combined control measures in Kampung Ampungan reduced the MfD-50 to 44% of the pre-treatment level over a period of 4 years. In the other two kampungs where only mass DEC therapy was applied, the microfilarial rate and MfD-50 declined significantly in the second blood survey but increased gradually in two subsequent follow-up blood surveys. The total insecticidal impact for Ma. bonneae was 3.9 to 1 indoors and 2.7 to 1 outdoors. These results indicated that quarterly pirimiphos-methyl indoor spraying used in integrated control could reduce indoor transmission by 3.9 times. The infective rate from the Ma. bonneae dissected in all three kampungs after the interventions, irrespective of DEC treatment alone or in combination with pirimiphos-methyl residual spraying were reduced by two fold. However the infection rate of brugian filarial larvae in Kampung Ampungan was significantly reduced after the use of DEC and insecticide. Annual Transmission Potential (ATP) showed a high significant reduction in Kampung Ampungan (p > 0.001) compared with Kampungs Sebangkoi and Schambam. In Ampungan, the ATP was reduced by 8.5 times indoors after the MDA and insecticidal application and 3 times outdoors. The reduction rate for Sebangkoi and Sebamban both indoors and outdoors were less than 2 fold.(ABSTRACT TRUNCATED AT 400 WORDS)

Matched MeSH terms: Culicidae/parasitology*
Efficacy of diethylcarbamazine and pirimiphos-methyl residual spraying in controlling brugian filariasis

Chang MS, Ho BC, Chan KL

Trop. Med. Parasitol., 1991 Jun;42(2):95-102.
PMID: 1680246

A control programme against subperiodic brugian filariasis was implemented in three villages, (Kg. Ampungan, Kg. Sebangkoi and Kg. Sebamban) in Sarawak, Malaysia. In Kampong Ampungan, the mass administration of diethylcarbamazine (DEC-citrate) combined with residual house spraying of pirimiphos-methyl reduced microfilarial rate to 8% of the pre-treatment level and microfilarial density (MfD50) to 44% of the pre-treatment level over a period of four years. In Kampong Sebangkoi and Kampong Sebamban, where only mass DEC therapy was applied, the microfilarial rate and MfD50 declined distinctly in the second blood survey but increased gradually in two subsequent follow-up blood surveys. In Kg, Ampungan, we observed a significant reduction of infective biting rate (88.3%), infection rate (62.5%) and transmission potential (88.1%) of Mansonia bonneae at the fourth spray round. The corresponding reduction rates in Kg. Sebangkoi and Kg. Sebamban were 35.3%, 26.7%, 42.2% and 24%, 30.8% and 15.4% respectively. The biting density of the vector was reduced by 79.8% indoors and 31.8% outdoors at the sprayed village, while only a slight decrease in densities (17.9% indoors and 12.4% outdoors) was observed at the unsprayed village. Bioassay tests revealed that pirimiphos-methyl had a substantial fumigant effect on the vector. The integrated control measure in controlling subperiodic brugian filariasis is discussed.

Matched MeSH terms: Culicidae/parasitology
Recent pathogen and mosquito host records from Penang Island, Malaysia

Chapman HC, Lacey LA, Yap HH

J Am Mosq Control Assoc, 1987 Jun;3(2):306-8.
PMID: 2904951
Matched MeSH terms: Culicidae/parasitology*
Armigeres subalbatus incriminated as an important vector of the dog heartworm Dirofilaria immitis and the bird Cardiofilaria in urban Kuala Lumpur

Cheong WH, Mak JW, Naidu S, Mahadevan S

Southeast Asian J. Trop. Med. Public Health, 1981 Dec;12(4):611-2.
PMID: 6124044
Matched MeSH terms: Culicidae/parasitology*
Update on the bionomics of Mansonia vectors of brugian filariasis

Chiang GL

Southeast Asian J. Trop. Med. Public Health, 1993;24 Suppl 2:69-75.
PMID: 7973951

The genus Mansonia is divided into two subgenera, Mansonia and Mansonioides. The subgenus Mansonioides includes the important vectors of lymphatic filariasis caused by Brugia malayi in South and Southeast Asia. Six species of this subgenus are vectors of two types of brugian filariasis, periodic and subperiodic. All six species, viz Mansonia bonneae, Ma. dives, Ma. uniformis, Ma. annulifera, Ma. annulata and Ma. indiana are present in this country. The ecological factors governing the larval and adult biology and their control measures are discussed.

Matched MeSH terms: Culicidae/parasitology
Comparative susceptibility of five strains of Mansonia uniformis (Diptera:Culicidae) in Malaysia to infection with subperiodic Brugia malayi

Chiang GL, Loong KP, Eng KL

Southeast Asian J. Trop. Med. Public Health, 1989 Jun;20(2):169-74.
PMID: 2575285

Five strains of Ma. uniformis from Malaysia were tested for their susceptibility to infection with subperiodic B. malayi. All were found to be susceptible with infection rates ranging from 62% to 100%. The susceptibility rates were directly related to the microfilarial densities of the cat at the time of feeding. Statistical analysis showed no significant difference (p greater than 0.05) among the means of the indices of experimental infection as well as the percentage of infective mosquitoes of the five strains and an old laboratory colony. They were all equally susceptible to subperiodic B. malayi.

Matched MeSH terms: Culicidae/parasitology*
Filariasis in Bengkoka Peninsula, Sabah, Malaysia: bionomics of Mansonia sp

Chiang GL, Cheong WH, Samarawickrema WA

Southeast Asian J. Trop. Med. Public Health, 1984 Sep;15(3):294-302.
PMID: 6151743

Studies on age groups within activity cycles, age composition and survivorship in natural populations of Mansonia in Kampung Pantai, Bengkoka Peninsula of Sabah state have been described. Early activity of 3-5 parous Ma. bonneae during the first hour after sunset was noted. Age composition of Ma. bonneae at forest shade, indoor and outdoor of house, comparative buffalo vs human bait outdoor in Kampung Pantai showed all round high parous rates ranging from 66.7 to 75.4%. Population 3-parous and older ranged from 18.8 to 26.7%. Nine of the 14 infective Ma. bonneae were 3-parous and this segment of the population was engaged in active transmission. High parous rates were observed in Ma. dives and Ma. uniformis taken in small numbers. Parous rates of Ma. bonneae taken in Kampung Delima and Kampung Taradas were also high. Estimates of daily survivorship of Ma. bonneae and Ma. dives determined by two methods were very high.

Matched MeSH terms: Culicidae/parasitology
Field studies on the surveillance of Coquillettidia crassipes (Van der Wulp) and the isolation of a strain of Cardiofilaria in peninsular Malaysia

Chiang GL, Samarawickrema WA, Eng KL, Cheong WH, Sulaiman I, Yap HH

Ann Trop Med Parasitol, 1986 Apr;80(2):235-44.
PMID: 2875691

Surveillance methods for Coquillettidia crassipes were studied in an open housing estate near Kuala Lumpur using three types of traps Trinidad 10 trap, modified Lard can trap and IMR trap, each baited with chicken or pigeon. All traps attracted Cq. crassipes. There was no significant difference in the catches in the three traps. There was also no significant difference between chicken and pigeon as bait. Catches at heights of 1.5, 3, 4.5 and 6 m did not show any significant difference in density. Cq. crassipes was active at night with an early peak during the first hour of the night and a minor peak between 0100 and 0200 hours. The activity of the parous and nulliparous sections of the population was similar, except that a higher proportion of the parous females was active during the second peak compared with the nulliparous females. The parous rate was 22.3%, and the probability of survival through one day for two gonotrophic cycles was 0.711 and 0.650. The infection rate for Cardiofilaria was 29 out of 1052 (2.76%) and the infective rate (L3 larvae) was 13 out of 1052 (1.24%). 48.3% of the infected Cq. crassipes had a worm burden of more than ten larvae. One of the chickens in the traps was positive for microfilariae of Cardiofilaria four weeks after exposure as bait. Laboratory bred Cq. crassipes fed on this chicken produced infective larvae in ten days, and these were inoculated into clean chickens and pigeons. Microfilariae appeared in the chickens but not in pigeons. The adult worms recovered await identification.

Matched MeSH terms: Culicidae/parasitology*
Field and laboratory observations on Coquillettidia crassipes in relation to transmission of Brugia malayi in Peninsular Malaysia

Chiang GL, Samarawickrema WA, Mak JW, Cheong WH, Sulaiman I, Yap HH

Ann Trop Med Parasitol, 1986 Feb;80(1):117-21.
PMID: 2873797

Field observations were made on Coquillettidia crassipes during a study of Mansonia in a swamp forest ecotype in Tanjong Karang. There was an increase in abundance in July consistent with the increase in abundance of Mansonia and an increase in rainfall. The biting cycle showed a dramatic early peak during the period 1900-2000 hours. The probability of daily survival through one day for the first three gonotrophic cycles was 0.770, 0.722 and 0.759. Two of the 54 Cq. crassipes dissected were infective, with two and 25 L3 larvae of Brugia. Both subperiodic B. malayi and B. pahangi developed into L3 larvae in laboratory bred Cq. crassipes. The index of experimental infection was higher for B. pahangi. Mansonia bonneae and Ma. uniformis showed higher indices of experimental infection than Cq. crassipes for subperiodic B. malayi. It is concluded that in an endemic area with a high density of Cq. crassipes it could act as a secondary vector of Brugian filariasis.

Matched MeSH terms: Culicidae/parasitology*
Fulltext Analysis of nuclear and organellar genomes of Plasmodium knowlesi in humans reveals ancient population structure and recent recombination among host-specific subpopulations

Diez Benavente E, Florez de Sessions P, Moon RW, Holder AA, Blackman MJ, Roper C, et al.

PLoS Genet, 2017 Sep;13(9):e1007008.
PMID: 28922357 DOI: 10.1371/journal.pgen.1007008

The macaque parasite Plasmodium knowlesi is a significant concern in Malaysia where cases of human infection are increasing. Parasites infecting humans originate from genetically distinct subpopulations associated with the long-tailed (Macaca fascicularis (Mf)) or pig-tailed macaques (Macaca nemestrina (Mn)). We used a new high-quality reference genome to re-evaluate previously described subpopulations among human and macaque isolates from Malaysian-Borneo and Peninsular-Malaysia. Nuclear genomes were dimorphic, as expected, but new evidence of chromosomal-segment exchanges between subpopulations was found. A large segment on chromosome 8 originating from the Mn subpopulation and containing genes encoding proteins expressed in mosquito-borne parasite stages, was found in Mf genotypes. By contrast, non-recombining organelle genomes partitioned into 3 deeply branched lineages, unlinked with nuclear genomic dimorphism. Subpopulations which diverged in isolation have re-connected, possibly due to deforestation and disruption of wild macaque habitats. The resulting genomic mosaics reveal traits selected by host-vector-parasite interactions in a setting of ecological transition.

Matched MeSH terms: Culicidae/parasitology
Lankesteria, a gregarine protozoan, previously unreported in mosquitoes of Malaysia

Else JG, Dangsupa P

Southeast Asian J. Trop. Med. Public Health, 1974 Sep;5(3):454.
PMID: 4154508
Matched MeSH terms: Culicidae/parasitology*
Diversity and natural selection of Merozoite surface Protein-1 in three species of human malaria parasites: Contribution from South-East Asian isolates

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: Culicidae/parasitology
Studies of Coquillettidia (coquillettidia) crassipes (Vanderwulp, 1881) in relation to transmission of Cardiofilaria nilesi

Klinkaewnarong W, Chiang GL, Eng KL

Southeast Asian J. Trop. Med. Public Health, 1985 Mar;16(1):10-4.
PMID: 2862708

Field surveillance of Cq. crassipes was conducted in an open housing estate near Kuala Lumpur using IMR traps baited with chicken and gerbils. Chicken bait attracted more Cq. crassipes. There was significant difference between chicken and gerbil as bait. The mosquitoes preferred to feed at canopy level. The parous rate was 20.41% and the infection rate for Cardiofilaria nilesi was 2.04%. None of the 120 chicken and 5 ducks, in a village close to the open housing estate, examined for microfilariae were positive. Ar. durhami and Ar. subalbatus did not support development of C. nilesi. However, Cq. crassipes is an extremely efficient vector of C. nilesi.

Matched MeSH terms: Culicidae/parasitology*
Fulltext The Plasmodium falciparum male gametocyte protein P230p, a paralog of P230, is vital for ookinete formation and mosquito transmission

Marin-Mogollon C, van de Vegte-Bolmer M, van Gemert GJ, van Pul FJA, Ramesar J, Othman AS, et al.

Sci Rep, 2018 10 08;8(1):14902.
PMID: 30297725 DOI: 10.1038/s41598-018-33236-x

Two members of 6-cysteine (6-cys) protein family, P48/45 and P230, are important for gamete fertility in rodent and human malaria parasites and are leading transmission blocking vaccine antigens. Rodent and human parasites encode a paralog of P230, called P230p. While P230 is expressed in male and female parasites, P230p is expressed only in male gametocytes and gametes. In rodent malaria parasites this protein is dispensable throughout the complete life-cycle; however, its function in P. falciparum is unknown. Using CRISPR/Cas9 methodology we disrupted the gene encoding Pfp230p resulting in P. falciparum mutants (PfΔp230p) lacking P230p expression. The PfΔp230p mutants produced normal numbers of male and female gametocytes, which retained expression of P48/45 and P230. Upon activation male PfΔp230p gametocytes undergo exflagellation and form male gametes. However, male gametes are unable to attach to red blood cells resulting in the absence of characteristic exflagellation centres in vitro. In the absence of P230p, zygote formation as well as oocyst and sporozoite development were strongly reduced (>98%) in mosquitoes. These observations demonstrate that P230p, like P230 and P48/45, has a vital role in P. falciparum male fertility and zygote formation and warrants further investigation as a potential transmission blocking vaccine candidate.

Matched MeSH terms: Culicidae/parasitology*
Current status of filariasis in Malaysia

Marzhuki MI, Tham AS, Poovaneswari S

Southeast Asian J. Trop. Med. Public Health, 1993;24 Suppl 2:10-4.
PMID: 7973937

The Filariasis Control Program was established more than 30 years ago in the country and the disease is still a public health problem in some states. Since 1983, a total of 17 filariasis control teams were formed throughout the country to carry out filariasis control work. The teams conduct house and population censuses, nocturnal mass blood surveys and treatment of microscopically confirmed cases. Individual case follow-up is being carried out after 3-5 months while the locality is resurveyed after about 2-3 years. During the years 1988 to 1990, there appeared to be a decreasing trend in the number of filariasis cases detected countrywide. In 1991, brugian filariasis accounted for 92% of the cases detected. The microfilaria rate (MFR) also showed a decreasing trend countrywide for the years 1988 (0.57%) to 1990 (0.35%) but there was an increase in 1991 although it remained well below the 5% MFR targeted in the program objective, In 1991, the filariasis control teams and the district multi-purpose teams collected a total of 167, 151 blood slides out of which 871 were found to be positive for microfilaria. To determine the true endemicity of filariasis in the country, the malaria district multi-purpose teams are also utilized to assist in probe surveys in new areas of the district. Two species of filarial worms, namely Brugia malayi and Wuchereria bancrofti, and the mosquito vectors belonging to the Anopheles and Mansonia genera are involved in the transmission of filariasis in Malaysia. Monkeys and domestic cats are the reservoir hosts for the subperiodic strain of B. malayi.

Matched MeSH terms: Culicidae/parasitology
Fulltext Predicting the geographical distributions of the macaque hosts and mosquito vectors of Plasmodium knowlesi malaria in forested and non-forested areas

Moyes CL, Shearer FM, Huang Z, Wiebe A, Gibson HS, Nijman V, et al.

Parasit Vectors, 2016 Apr 28;9:242.
PMID: 27125995 DOI: 10.1186/s13071-016-1527-0

BACKGROUND: Plasmodium knowlesi is a zoonotic pathogen, transmitted among macaques and to humans by anopheline mosquitoes. Information on P. knowlesi malaria is lacking in most regions so the first step to understand the geographical distribution of disease risk is to define the distributions of the reservoir and vector species.
METHODS: We used macaque and mosquito species presence data, background data that captured sampling bias in the presence data, a boosted regression tree model and environmental datasets, including annual data for land classes, to predict the distributions of each vector and host species. We then compared the predicted distribution of each species with cover of each land class.
RESULTS: Fine-scale distribution maps were generated for three macaque host species (Macaca fascicularis, M. nemestrina and M. leonina) and two mosquito vector complexes (the Dirus Complex and the Leucosphyrus Complex). The Leucosphyrus Complex was predicted to occur in areas with disturbed, but not intact, forest cover (> 60% tree cover) whereas the Dirus Complex was predicted to occur in areas with 10-100% tree cover as well as vegetation mosaics and cropland. Of the macaque species, M. nemestrina was mainly predicted to occur in forested areas whereas M. fascicularis was predicted to occur in vegetation mosaics, cropland, wetland and urban areas in addition to forested areas.
CONCLUSIONS: The predicted M. fascicularis distribution encompassed a wide range of habitats where humans are found. This is of most significance in the northern part of its range where members of the Dirus Complex are the main P. knowlesi vectors because these mosquitoes were also predicted to occur in a wider range of habitats. Our results support the hypothesis that conversion of intact forest into disturbed forest (for example plantations or timber concessions), or the creation of vegetation mosaics, will increase the probability that members of the Leucosphyrus Complex occur at these locations, as well as bringing humans into these areas. An explicit analysis of disease risk itself using infection data is required to explore this further. The species distributions generated here can now be included in future analyses of P. knowlesi infection risk.

Matched MeSH terms: Culicidae/parasitology

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