Larval habitat diversity and Anopheles mosquito species distribution in different ecological zones in Ghana

Abstract Background Understanding the ecology of larval malaria and lymphatic filariasis mosquitoes in a changing environment is important in developing effective control tools or programmes. This study characterized the breeding habitats of Anopheles mosquitoes in rural communities in different ecological zones in Ghana during the dry and rainy seasons. Methods The spatio-temporal distribution, species composition, and abundance of larval Anopheles mosquitoes in breeding habitats were studied in five locations in three ecological zones of Ghana. These were Anyakpor (coastal savannah area), Duase (forest area), and Libga, Pagaza, and Kpalsogu (Sahel savannah area). Larvae were collected using standard dippers and were raised in the insectary for identification. Results Out of a total of 7984 mosquito larvae collected, 2152 (27.26%) were anophelines and were more abundant in the rainy season (70.82%) than in the dry season (29.18%). The anophelines comprised 2128 (98.88%) An. gambiae s.l., 16 (0.74%) An. rufipes, and 8 (0.37%) An. pharoensis. In the coastal savannah and forest zones, dug-out wells were the most productive habitat during the dry (1.59 larvae/dip and 1.47 larvae/dip) and rainy seasons (11.28 larvae/dip and 2.05 larvae/dip). Swamps and furrows were the most productive habitats in the Sahel savannah zone during the dry (0.25 larvae/dip) and rainy (2.14 larvae/dip) seasons, respectively. Anopheles coluzzii was the most abundant sibling species in all the ecological zones. Anopheles melas and An. arabiensis were encountered only in the coastal savannah and the Sahel savannah areas, respectively. Larval habitat types influenced the presence of larvae as well as larval density (p < 0.001). The land-use type affected the presence of Anopheles larvae (p = 0.001), while vegetation cover influenced larval density (p < 0.05). Conclusion The most productive habitats were dug-out wells in the coastal savannah and forest zones, and furrows from irrigated canals in the Sahel savannah zone. Anopheles coluzzii was the predominant vector species in all the ecological zones. The abundance of Anopheles breeding habitats and larvae were influenced by anthropogenic activities. Encouraging people whose activities create the larval habitats to become involved in larval source management such as habitat manipulation to stop mosquito breeding will be important for malaria and lymphatic filariasis control.

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Ecology of Anopheles Mosquito Larvae in Different Ecological Zones in Ghana

10.21203/rs.3.rs-154046/v1 ◽

2021 ◽

Author(s):

Isaac Amankona Hinne ◽

Simon Kwaku Attah ◽

Benedicta Ayiedu Mensah ◽

Akua Obeng Forson ◽

Yaw Asare Afrane

Keyword(s):

Rural Communities ◽

Rainy Season ◽

Anthropogenic Activities ◽

Temporal Distribution ◽

Larval Habitat ◽

Dry Season ◽

Effective Control ◽

Mosquito Larvae ◽

Ecological Zones ◽

Breeding Habitats

Abstract Background: Understanding the ecology of larval malaria mosquitoes is important in a changing environment is important in developing effective control tools or programmes. This study characterized the breeding habitats of Anopheles mosquitoes in rural communities in different ecological zones in Ghana during the dry and rainy seasons.Methods: The spatio-temporal distribution, species composition, and abundance of larval Anopheles mosquitoes in breeding habitats were studied in 3 ecological zones of Ghana. These were Anyakpor (Coastal Savanna area), Duase (Forest area), Libga, Pagazaa, and Kpalsogu (Sahel Savanna area). Larvae were collected using standard dippers and were raised in the insectary for identification. Results: Out of a total of 7,984 mosquito larvae collected, 2,152 (27.26%) were Anophelines and were more abundant in the rainy season (70.82%) than in the dry season (29.18 %). The Anophelines were made up of 2,128 (98.88%) An. gambiae s.l., 16 (0.74%) An. rufipees and 8 (0.37%) An. pharoensis. In Anyakpor and Duase, dug-out wells were the most productive habitat in the dry (1.59 larvae/dip and 1.47 larvae/dip) and rainy seasons (11.28 larvae/dip and 2.05 larvae/dip). The most productive habitats in Kpalsogu were natural ponds in the dry season (0.89 larvae/dip) and swamps in the rainy season (2.57 larvae/dip). In Libga, the most productive habitats were drainage ditches in the dry season (0.30 larvae/dip) and furrows in the rainy season (1.83 larvae/dip). The most productive habitats in Pagazaa were puddles (1.44 larvae/dip). Anopheles coluzii was the most abundant sibling species in all the ecological zones except Libga in the sahel savannah area where An. gambiae s.s was the most abundant. Anopheles melas and An. arabiensis were encountered only in the coastal savannah and the sahel savanna areas respectively. Larval habitat types influenced the presence of larvae as well as larval densities (p < 0.001). The land-use type affected the presence of Anopheles larvae (p = 0.001), while vegetation cover influenced larval densities (p < 0.05). Conclusion: The study revealed that the abundance of Anopheles breeding habitats and hence Anopheles larvae are closely associated with anthropogenic activities. Regulating such activities will lead to a significant reduction in Anopheles breeding habitats.

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Larval habitat diversity and mosquito species distribution along the coast of Kenya

Wellcome Open Research ◽

10.12688/wellcomeopenres.15550.1 ◽

2019 ◽

Vol 4 ◽

pp. 175 ◽

Cited By ~ 1

Author(s):

Miriam Karuitha ◽

Joel Bargul ◽

Joel Lutomiah ◽

Simon Muriu ◽

Joseph Nzovu ◽

...

Keyword(s):

Species Diversity ◽

Aedes Aegypti ◽

Urban Areas ◽

Mosquito Species ◽

Habitat Diversity ◽

Larval Habitat ◽

Control Measures ◽

Effective Control ◽

Aquatic Habitats ◽

Forested Areas

Background: Management of arboviruses relies heavily on vector control. Implementation and sustenance of effective control measures requires regular surveillance of mosquito occurrences, species abundance and distribution. The current study evaluated larval habitat diversity and productivity, mosquito species diversity and distribution in selected sites along the coast of Kenya. Methods: A cross-sectional survey of mosquito breeding habitats, species diversity and distribution was conducted in urban, peri-urban and forested ecological zones in Mombasa and Kilifi counties. Results: A total of 13,009 immature mosquitoes were collected from 17 diverse aquatic habitats along the coast of Kenya. Larval productivity differed significantly (F (16, 243) = 3.21, P < 0.0001) among the aquatic habitats, with tyre habitats recording the highest larval population. Culex pipiens (50.17%) and Aedes aegypti (38.73%) were the dominant mosquito species in urban areas, while Ae. vittatus (89%) was the dominant species in forested areas. In total, 4,735 adult mosquitoes belonging to 19 species were collected in Haller Park, Bamburi, Gede and Arabuko Sokoke forest. Urban areas supported higher densities of Ae. aegypti compared to peri-urban and forest areas, which, on the other hand, supported greater mosquito species diversity. Conclusions: High Ae. aegypti production in urban and peri-urban areas present a greater risk of arbovirus outbreaks. Targeting productive habitats of Aedes aegypti, such as discarded tyres, containers and poorly maintained drainage systems in urban areas and preventing human-vector contact in peri-urban and forested areas could have a significant impact on the prevalence of arboviruses along the coast of Kenya, forestalling the periodic outbreaks experienced in the region.

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Assessment of the developmental success of Anopheles coluzzii larvae under different nutrient regimes: effects of diet quality, food amount and larval density

Malaria Journal ◽

10.1186/s12936-018-2530-z ◽

2018 ◽

Vol 17 (1) ◽

Cited By ~ 1

Author(s):

Patric Stephane Epopa ◽

Hamidou Maiga ◽

Domonbabele François de Sales Hien ◽

Roch Kounbobr Dabire ◽

Rosemary Susan Lees ◽

...

Keyword(s):

Diet Quality ◽

Larval Density ◽

Anopheles Coluzzii ◽

Quality Food

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LAMA HIDUP DAN POTENSI Culex quinquefasciatus SEBAGAI VEKTOR FILARIASIS LIMFATIK BERDASARKAN KETINGGIAN PASCA TRANSMISSION ASSESMENT SURVEY (TAS) DI KABUPATEN SUBANG, JAWA BARAT

Vektora Jurnal Vektor dan Reservoir Penyakit ◽

10.22435/vk.v12i2.3241 ◽

2020 ◽

Vol 12 (2) ◽

pp. 155-166

Author(s):

Endang Puji Astuti ◽

Mutiara Widawati ◽

Yuneu Yuliasih ◽

Andri Ruliansyah ◽

Asep Jajang Kusnandar

Keyword(s):

Lymphatic Filariasis ◽

Mosquito Species ◽

Evaluation Study ◽

P Value ◽

Mosquito Abundance ◽

Biting Rate ◽

Human Landing ◽

The Relationship ◽

Density Behavior ◽

Entomological Data

The study on the bioecology of Lymphatic Filariasis (LF) vector is necessary to be used as a support to eliminate LF due to the lack of entomological data for LF vector in Subang, especially after the Provision of Mass Drug Administration for Filariasis Prevention. This study aims to identify mosquito species, density, behavior, longevity, presence of the filaria worm in mosquitoes, and to identify the distribution of mosquitoes in the highlands and lowlands in selected villages in Subang district. This study is part of Lymphatic filariasis (multicenter) evaluation study in Indonesia. The data was collected by using human landing collection method and vector habitat survey data. The entomological data analyzed from the calculation of Man hour density (MHD), Man biting rate (MBR), and longevity, while the relationship between variables and mosquito abundance using Pearson's correlation. The results indicated that the density of mosquitoes caught in Rancahilir was higher than Curug rendeng villages, these results are similar to the LF vector suspect mosquito (Cx. quinquefasciatus). These mosquitoes are found outdoor with peak densities at 22.00-23.00 West Indonesia Time. Altitude has an association with the density of mosquitoes (p-value 0.039). The longevity of Cx. quinquefasciatus population is 10-13 days. At that longevity, vectors are at risk for infective filarial worms. The result shows that Cx. quinquefasciatus collected in this study was negative for filarial worms. Based on the results of this study, we conclude that in Subang, filariasis transmission chain prevention has been successful. However, periodic evaluations is still need to be carried out in order to prevent re-infection of the disease. Abstrak Kajian tentang bioekologi nyamuk vektor Lymphatic Filariasis (LF) di Kabupatem Subang perlu dilakukan. Kajian ini sebagai pendukung untuk menuju eliminasi LF mengingat belum optimalnya data entomologi nyamuk vektor di Subang, terutama pasca Pemberian Obat Masal Pencegahan (POMP) filariasis. Penelitian ini bertujuan mengidentifikasi spesies, kepadatan, perilaku, umur panjang (longevity) populasi nyamuk, identifikasi keberadaan cacing filaria pada nyamuk vektor LF serta menganalisis perbedaan distribusi nyamuk pada dataran tinggi dan rendah di desa terpilih di Kabupaten Subang. Penelitian ini merupakan analisis lanjut dari penelitian “Studi evaluasi filariasis (multicenter) di Indonesia” yang dilaksanakan di beberapa kabupaten di Indonesia. Data yang diambil, yaitu data survei vektor yang menggunakan metode Human Landing Collection (HLC) dan survei habitat vektor. Analisa data entomologi menggunakan perhitungan Man hour density (MHD), Man-biting rate (MBR) dan nilai umur panjang nyamuk (longevity), sedangkan hubungan antar variabel dengan kepadatan menggunakan korelasi pearson. Hasil penelitian menunjukkan bahwa kepadatan nyamuk yang tertangkap di Desa Rancahilir (dataran rendah) lebih banyak dibandingkan di Desa Curug rendeng (dataran tinggi), termasuk kepadatan nyamuk Cx. quinquefasciatus yang juga dominan di wilayah ini. Nyamuk ini banyak ditemukan di luar rumah dengan puncak kepadatan pada jam 22.00-23.00 WIB. Ketinggian mempunyai hubungan dengan kepadatan nyamuk tertangkap (p value 0,039). Umur populasi nyamuk Cx. quinquefasciatus 10-13 hari. Umur ini menunjukkan umur populasi yang berisiko untuk infektif cacing filaria. Hasil pemeriksaan nyamuk Cx. quinquefasciatus negatif terhadap cacing filarial. Hasil ini menunjukkan bahwa di Kabupaten Subang telah berhasil memutuskan rantai penularan filaria. Namun, masih perlu dilaksanakan evaluasi berkala agar tidak terjadi penularan kembali di wilayah ini.

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Transmission Dynamics of Lymphatic Filariasis: A Mathematical Approach

ISRN Biomathematics ◽

10.5402/2012/930130 ◽

2012 ◽

Vol 2012 ◽

pp. 1-9 ◽

Cited By ~ 4

Author(s):

C. P. Bhunu ◽

S. Mushayabasa

Keyword(s):

Numerical Simulations ◽

Lymphatic Filariasis ◽

Reproduction Number ◽

Epidemiological Model ◽

Transmission Dynamics ◽

Effective Control ◽

Mathematical Approach

An epidemiological model for the spread of lymphatic filariasis, a mosquito-borne infection, is developed and analysed. The epidemic thresholds known as the reproduction number and equilibria for the model are determined and stabilities analysed. Results from the analysis of the reproduction number suggest that treatment will somehow contribute to a reduction in lymphatic filariasis cases, but what it does not show is the magnitude of the reduction, a part answered by the numerical simulations. Numerical simulations show that even when all lymphatic filariasis cases displaying elephantiasis symptoms are put on treatment it will not be able to eradicate the disease. This result suggests that effective control of lymphatic filariasis may lie in treatment for those displaying symptoms as well as chemoprophylaxis for the exposed.

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Phenotypic Insecticide Resistance in Anopheles gambiae (Diptera: Culicidae): Specific Characterization of Underlying Resistance Mechanisms Still Matters

Journal of Medical Entomology ◽

10.1093/jme/tjaa195 ◽

2020 ◽

Author(s):

Adandé A Medjigbodo ◽

Luc S Djogbenou ◽

Aubin A Koumba ◽

Laurette Djossou ◽

Athanase Badolo ◽

...

Keyword(s):

Insecticide Resistance ◽

Anopheles Gambiae ◽

Resistance Mechanisms ◽

Malaria Vectors ◽

Effective Control ◽

Anopheles Coluzzii ◽

Anopheles Gambiae S.S ◽

Diagnostic Dose ◽

Pirimiphos Methyl ◽

Old Adult

Abstract An effective control of malaria vectors requires an extensive knowledge of mechanisms underlying the resistance-phenotypes developed by these vectors against insecticides. We investigated Anopheles gambiae mosquitoes from Benin and Togo for their intensity of insecticide resistance and we discussed the involvement of genotyped mechanisms in the resistance-phenotypes observed. Three- to five-day-old adult mosquitoes emerged from field and laboratory An. gambiae larvae were assayed using WHO tube intensity tests against various doses of deltamethrin: 1× (0.05%); 2× (0.1%); 5× (0.25%); 7.5× (0.375%) and those of pirimiphos-methyl: 0.5× (0.125%); 1× (0.25%). Members of An. gambiae complex were screened in field populations using polymerase chain reaction (PCR) assays. The presence of kdrR(1014F/1014S) and ace-1R(119S) mutations was also investigated using TaqMan and PCR-RFLP techniques, respectively. Anopheles gambiae from field were very resistant to deltamethrin, whereas KisKdr and AcerKdrKis strains displayed 100% mortality rates at 2× the diagnostic dose. In contrast, the field mosquitoes displayed a low resistance-intensity against 1× the diagnostic dose of pirimiphos-methyl, whereas AcerKis and AcerKdrKis strains showed susceptibility at 0.5× the diagnostic dose. Anopheles gambiae s.s., Anopheles coluzzii, and Anopheles arabiensis were identified. Allelic frequencies of kdrR (1014F) and ace-1R (119S) mutations in the field populations varied from 0.65 to 1 and 0 to 0.84, respectively. The field An. gambiae displayed high-resistance levels against deltamethrin and pirimiphos-methyl when compared with those of the laboratory An. gambiae-resistant strains. These results exhibit the complexity of underlying insecticide resistance mechanisms in these field malaria vectors.

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Larval breeding habitats and ecological factors influence the species composition of mosquito (Diptera : Culicidae) in the parks of Dhaka city, Bangladesh

Bangladesh Journal of Zoology ◽

10.3329/bjz.v45i2.35706 ◽

2018 ◽

Vol 45 (2) ◽

pp. 111-122 ◽

Cited By ~ 2

Author(s):

Afroza Sultana ◽

Sharmin Hasan ◽

Mosharraf Hossain ◽

Abdul Alim ◽

Mohammad Al Mamun ◽

...

Keyword(s):

Mosquito Control ◽

Mosquito Species ◽

Ecological Factors ◽

Control Program ◽

Breeding Habitat ◽

Coconut Shell ◽

Larval Abundance ◽

Tree Hole ◽

Breeding Habitats ◽

Tree Holes

Mosquito larval ecology is prerequisite for determining the larval abundance and species assemblage in mosquito control program. The study explored the association of five mosquito species with their breeding habitat diversity and species distribution in three selected parks from May to October, 2015. A total of 3217 mosquito larvae were reported from six breeding habitats, namely tree hole, leaf axils, water bottle, tire, drain and coconut shell. The frequency of the three species (Ae. aegypti, Ae. albopictus and Ar. subalbatus) coexistence was higher in tree holes (82.4%) than that of the other coexisting species. Pearson Chi-square result revealed that the association of species was significantly dependent on the breeding habitats. ANOVA further suggested that mosquito density varied across habitats where among the highest density of Cx. quinquefasciatus (3.87 ± 0.22) found in drain, followed by both Ae. albopictus (2.02 ± 0.17) and Ar. subalbatus (0.50 ± 0.09) in tree holes and Ae. aegypti (1.25 ± 0.23) in coconut shell. Cx. tritaeniorhynchus occurred in drain with the least observed density (0.03 ± 0.01). CCA results suggested that Aedes species were likely preferred to oviposit in shaded habitats where pH was associated with Ae. albopictus and dissolved oxygen was with Ae. aegypti and Ar. subalbatus. Culex species were positively associated with the habitats characterizing muddy bottom and emerging vegetation but not with any of the physico-chemical parameters. These findings concluded that ecological factors influence mosquito species to favor their breeding habitats can be helpful in controlling targeted vector species as well as the mosquito borne diseases.Bangladesh J. Zool. 45(2): 111-122, 2017

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In Silico Karyotyping of Chromosomally Polymorphic Malaria Mosquitoes in the Anopheles gambiae Complex

G3 Genes|Genome|Genetics ◽

10.1534/g3.119.400445 ◽

2019 ◽

Vol 9 (10) ◽

pp. 3249-3262 ◽

Cited By ~ 6

Author(s):

R. Rebecca Love ◽

Seth N. Redmond ◽

Marco Pombi ◽

Beniamino Caputo ◽

Vincenzo Petrarca ◽

...

Keyword(s):

Anopheles Gambiae ◽

In Silico ◽

Mosquito Species ◽

Chromosomal Rearrangements ◽

Small Subset ◽

Anopheles Coluzzii ◽

Strongly Correlated ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Malaria Mosquitoes

Chromosomal inversion polymorphisms play an important role in adaptation to environmental heterogeneities. For mosquito species in the Anopheles gambiae complex that are significant vectors of human malaria, paracentric inversion polymorphisms are abundant and are associated with ecologically and epidemiologically important phenotypes. Improved understanding of these traits relies on determining mosquito karyotype, which currently depends upon laborious cytogenetic methods whose application is limited both by the requirement for specialized expertise and for properly preserved adult females at specific gonotrophic stages. To overcome this limitation, we developed sets of tag single nucleotide polymorphisms (SNPs) inside inversions whose biallelic genotype is strongly correlated with inversion genotype. We leveraged 1,347 fully sequenced An. gambiae and Anopheles coluzzii genomes in the Ag1000G database of natural variation. Beginning with principal components analysis (PCA) of population samples, applied to windows of the genome containing individual chromosomal rearrangements, we classified samples into three inversion genotypes, distinguishing homozygous inverted and homozygous uninverted groups by inclusion of the small subset of specimens in Ag1000G that are associated with cytogenetic metadata. We then assessed the correlation between candidate tag SNP genotypes and PCA-based inversion genotypes in our training sets, selecting those candidates with >80% agreement. Our initial tests both in held-back validation samples from Ag1000G and in data independent of Ag1000G suggest that when used for in silico inversion genotyping of sequenced mosquitoes, these tags perform better than traditional cytogenetics, even for specimens where only a small subset of the tag SNPs can be successfully ascertained.

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Analysis of Length of Growing Season in Some Agro-ecological Zones Using Non-parametric Trend Test

Notulae Scientia Biologicae ◽

10.15835/nsb11210314 ◽

2019 ◽

Vol 11 (2) ◽

pp. 241-248

Author(s):

Olumuyiwa Idowu OJO ◽

Charity C. TEMENU ◽

Masengo Francois ILUNGA

Keyword(s):

Rainy Season ◽

Daily Rainfall ◽

Growing Season ◽

Trend Test ◽

Rainfall Characteristics ◽

Land Preparation ◽

Ecological Zones ◽

Agricultural Enterprise ◽

Savannah Zone ◽

Agro Ecological Zones

The ever increasing population and consequently increase in demand for food and the increasing exploitation of the land justifies the need for adequate studies on rainfall as an important factor affecting agricultural production. The date of the onset of rains is an important factor in planning agricultural operations such as land preparation and sowing. The study conducted agro-statistical analysis of rainfall characteristics over three different zones of Nigeria. Daily rainfall data were collected for the period between 1971 and 2005 for 6 stations and were subjected to standard analysis to determine trends and variations in the onset dates, cessation dates, length of rainy season, number of wet days, drought episodes. The results showed that the inter-annual variability of the onset dates is higher than that of cessation dates with a progressive shift in both onset and cessation dates. The length of rainy season varied from 77-291 days in Guinea zone, 77-243 days for Savannah and 73-155 days for the Sahel. Changes in the length of growing season ranged between -9 and -10 for Guinea zone, -21 and 11 days for Savannah zone and -28 and 20 days for the Sahel. Similarly, the numbers of wet days have declined over Nigeria. The information presented in this study are to serve as input for proper land and water resources management for productive agricultural enterprise across the three major agro-ecological zones of Nigeria.

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Species Composition and Diversity of Malaria Vector Breeding Habitats in Trincomalee District of Sri Lanka

BioMed Research International ◽

10.1155/2015/823810 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 8

Author(s):

Nayana Gunathilaka ◽

Wimaladharma Abeyewickreme ◽

Menaka Hapugoda ◽

Rajitha Wickremasinghe

Keyword(s):

Sri Lanka ◽

Larval Habitat ◽

Malaria Vectors ◽

Entomological Surveillance ◽

Anopheles Subpictus ◽

Control Programs ◽

Breeding Habitats ◽

Elimination Programme ◽

Total Dissolved Solid ◽

The Relationship

Introduction. Mosquito larval ecology is important in determining larval densities and species assemblage. This in turn influences malaria transmission in an area. Therefore, understanding larval habitat ecology is important in designing malaria control programs.Method. Larval surveys were conducted in 20 localities under five sentinel sites (Padavisiripura, Gomarankadawala, Thoppur, Mollipothana, and Ichchallampaththu) in Trincomalee District, Eastern Province of Sri Lanka, between June 2010 and July 2013. The relationship between seven abiotic variables (temperature, pH, conductivity, Total Dissolved Solid (TDS), turbidity, Dissolved Oxygen (DO), and salinity) was measured.Results. A total of 21,347 anophelines were recorded representing 15 species.Anopheles subpictus24.72% (5,278/21,347) was the predominant species, followed by 24.67% (5,267/21,347) ofAn. nigerrimusand 14.56% (3,109/21,347) ofAn. peditaeniatus. A total of 9,430 breeding habitats under twenty-one categories were identified.An. culcicifacieswas noted to be highest from built wells (20.5%) with high salinity (1102.3 ± 81.8 mg/L), followed by waste water collections (20.2%) having low DO levels (2.85 ± 0.03 mg/L) and high TDS (1,654 ± 140 mg/L).Conclusion. This study opens an avenue to explore new breeding habitats of malaria vectors in the country and reemphasizes the requirement of conducting entomological surveillance to detect potential transmission of malaria in Sri Lanka under the current malaria elimination programme.

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