Molecular Identification, Species Composition and Distribution Maps of Malaria Vector Species in SelectedCommunities in Benue State, North Central Nigeria.

Abstract Background Vector control through long-lasting insecticidal nets (LLINs) and focal indoor residual spraying (IRS) is a major component of the Tanzania national malaria control strategy. In mainland Tanzania, IRS has been conducted annually around Lake Victoria basin since 2007. Due to pyrethroid resistance in malaria vectors, use of pyrethroids for IRS was phased out and from 2014 to 2017 pirimiphos-methyl (Actellic® 300CS) was sprayed in regions of Kagera, Geita, Mwanza, and Mara. Entomological surveillance was conducted in 10 sprayed and 4 unsprayed sites to determine the impact of IRS on entomological indices related to malaria transmission risk. Methods WHO cone bioassays were conducted monthly on interior house walls to determine residual efficacy of pirimiphos-methyl CS. Indoor CDC light traps with or without bottle rotator were hung next to protected sleepers indoors and also set outdoors (unbaited) as a proxy measure for indoor and outdoor biting rate and time of biting. Prokopack aspirators were used indoors to capture resting malaria vectors. A sub-sample of Anopheles was tested by PCR to determine species identity and ELISA for sporozoite rate. Results Annual IRS with Actellic® 300CS from 2015 to 2017 was effective on sprayed walls for a mean of 7 months in cone bioassay. PCR of 2016 and 2017 samples showed vector populations were predominantly Anopheles arabiensis (58.1%, n = 4,403 IRS sites, 58%, n = 2,441 unsprayed sites). There was a greater proportion of Anopheles funestus sensu stricto in unsprayed sites (20.4%, n = 858) than in sprayed sites (7.9%, n = 595) and fewer Anopheles parensis (2%, n = 85 unsprayed, 7.8%, n = 591 sprayed). Biting peaks of Anopheles gambiae sensu lato (s.l.) followed periods of rainfall occurring between October and April, but were generally lower in sprayed sites than unsprayed. In most sprayed sites, An. gambiae s.l. indoor densities increased between January and February, i.e., 10–12 months after IRS. The predominant species An. arabiensis had a sporozoite rate in 2017 of 2.0% (95% CI 1.4–2.9) in unsprayed sites compared to 0.8% (95% CI 0.5–1.3) in sprayed sites (p = 0.003). Sporozoite rates were also lower for An. funestus collected in sprayed sites. Conclusion This study contributes to the understanding of malaria vector species composition, behaviour and transmission risk following IRS around Lake Victoria and can be used to guide malaria vector control strategies in Tanzania.

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Malaria vector species composition and entomological indices following indoor residual spraying in regions bordering Lake Victoria, Tanzania

10.21203/rs.3.rs-27952/v3 ◽

2020 ◽

Author(s):

Charles Elias Kakilla ◽

Alphaxard Manjurano ◽

Karen Nelwin ◽

Jackline Martin ◽

Fabian Mashauri ◽

...

Keyword(s):

Species Composition ◽

Vector Control ◽

Malaria Vector ◽

Lake Victoria ◽

Indoor Residual Spraying ◽

Transmission Risk ◽

Malaria Vectors ◽

Vector Species ◽

Sporozoite Rate ◽

Pirimiphos Methyl

Abstract BackgroundVector control through long-lasting insecticidal nets (LLINs) and focal indoor residual spraying (IRS) is a major component of the Tanzania national malaria control strategy. In mainland Tanzania, IRS has been conducted annually around Lake Victoria basin since 2007. Due to pyrethroid resistance in malaria vectors, use of pyrethroids for IRS was phased out and from 2014 to 2017 pirimiphos-methyl (Actellic® 300CS) was sprayed in regions of Kagera, Geita, Mwanza, and Mara. Entomological surveillance was conducted in 10 sprayed and 4 unsprayed sites to determine the impact of IRS on entomological indices related to malaria transmission risk.MethodsWHO cone bioassays were conducted monthly on interior house walls to determine residual efficacy of pirimiphos-methyl CS. Indoor CDC light traps with or without bottle rotator were hung next to protected sleepers indoors and also set outdoors (unbaited) as a proxy measure for indoor and outdoor biting rate and time of biting. Prokopack aspirators were used indoors to capture potentially resting malaria vectors. A sub-sample of Anopheles was tested by PCR to determine species identity and ELISA for sporozoite rate. ResultsAnnual IRS with Actellic® 300CS from 2015 to 2017 was effective on sprayed walls for a mean of 7 months in cone bioassay. PCR of 2016 and 2017 samples showed vector populations were predominantly Anopheles arabiensis (58.1%, n=4,403 IRS sites, 58%, n=2,441 unsprayed sites). There was a greater proportion of Anopheles funestus sensu stricto (s.l) in unsprayed sites (20.4%, n=858) than in sprayed sites (7.9%, n=595) and fewer Anopheles parensis (2%, n=85 unsprayed, 7.8%, n=591 sprayed). Biting peaks of Anopheles gambiae sensu lato (s.l.) followed periods of rainfall occurring between October and April, but were generally lower in sprayed sites than unsprayed. In most sprayed sites, An. gambiae s.l. indoor densities increased between January and February, i.e., 10-12 months after IRS. The predominant species An. arabiensis had a sporozoite rate in 2017 of 2.0% (95% CI: 1.4-2.9) in unsprayed sites compared to 0.8% (95% CI: 0.5-1.3) in sprayed sites (p=0.003). Sporozoite rates were also lower for An. funestus collected in sprayed sites. ConclusionThis study contributes to the understanding of malaria vector species composition, behaviour and transmission risk following IRS around Lake Victoria and can be used to guide malaria vector control strategies in Tanzania.

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Malaria vector species composition and relative abundance in Mutare and Mutasa districts, Zimbabwe

Journal of Entomological and Acarological Research ◽

10.4081/jear.2015.4955 ◽

2015 ◽

Vol 47 (3) ◽

pp. 79 ◽

Cited By ~ 7

Author(s):

S. Sande ◽

M. Zimba ◽

P. Chinwada ◽

H.T. Masendu ◽

A. Makuwaza

Keyword(s):

Species Composition ◽

Relative Abundance ◽

Malaria Vector ◽

Sibling Species ◽

Mosquito Species ◽

Sensu Stricto ◽

Malaria Vectors ◽

Morphological Identification ◽

Vector Species ◽

Vector Behaviour

Regular entomological monitoring is important to determine changes in mosquito species composition and relative densities of malaria vectors in relation to vector control interventions. A study to gain insights into malaria vector species composition and relative abundance was undertaken in Mutare and Mutasa districts, Zimbabwe. Two methods; indoor resting catches and larval sampling were used to collect indoor resting adults and larvae from May 2013 to April 2014. Mosquitoes collected as adults and reared from larvae that were identified morphologically as potential malaria vectors were further processed to sibling species by polymerase chain reaction (PCR). Morphological identification of anopheline mosquitoes showed presence of two complexes: An. funestus and An. gambiae. The total number of female members of the An. funestus group and An. gambiae complex collected by both methods from the two sites was 840 and 31 respectively. Malaria vector species of both complexes were more abundant in Mutare than in Mutasa. The PCR-based assays showed the presence of four sibling species: An. funestus sensu stricto (90.8%, 267/294) and An. leesoni (5.1%, 15/294), of An. funestus group; An. arabiensis (41.9%, 13/31) and An. quadriannulatus (48.4%, 15/31) of the An. gambiae complex. About 4% and 5% of specimens of An. gambiae complex and An. funestus group respectively did not amplify. Of the two identified malaria vector sibling species, An. funestus sensu stricto was more abundant (95.4%, 267/280) than An. arabiensis (4.6%, 13/280), suggesting the replacement to secondary vector of An. arabiensis, which was previously the predominant vector species. An. funestus sensu stricto and An. arabiensis, the most important vectors of human malaria were identified in this study, but their resting and biting habits as well as insecticide susceptibility are unclear. Further studies on vector behaviour are therefore recommended.

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Shifts in malaria vector species composition and transmission dynamics along the Kenyan coast over the past 20 years

Malaria Journal ◽

10.1186/1475-2875-12-13 ◽

2013 ◽

Vol 12 (1) ◽

Cited By ~ 114

Author(s):

Joseph M Mwangangi ◽

Charles M Mbogo ◽

Benedict O Orindi ◽

Ephantus J Muturi ◽

Janet T Midega ◽

...

Keyword(s):

Species Composition ◽

Malaria Vector ◽

Transmission Dynamics ◽

Vector Species ◽

The Past ◽

Kenyan Coast

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Freshwater gastropods of the western part of the Kola Peninsula and northern Karelia (northern Europe)

Ruthenica, Russian Malacological Journal ◽

10.35885/ruthenica.2021.31(4).1 ◽

2021 ◽

Vol 31 (4) ◽

pp. 147-175

Author(s):

Ivan O. Nekhaev

Keyword(s):

Species Composition ◽

Kola Peninsula ◽

Barents Sea ◽

Common Species ◽

Northern Taiga ◽

Northern Europe ◽

Indigenous Species ◽

Freshwater Gastropods ◽

Distribution Maps ◽

Species Composition And Distribution

The species composition and distribution of freshwater gastropods in the western part of the Kola Peninsula and northern Karelia has been studied. The explored region lies in the far north of Europe and covers several landscape zones: from the northern taiga to the tundra. In sum, seventeen species were found, for each of them the distribution maps and photographs of intraspecific forms of conchological variability are presented. The taxonomic remarks are also given when appropriate. Gyraulus acronicus (Planorbidae) and Ampullacena balthica (Lymnaeidae) are the most common species in the studied region. Two species ( Ampullacena balthica and Galba truncatula ) have been recorded in the Barents Sea islands off the Kola Peninsula. A single non-indigenous species, Physella acuta (Physidae) has been registered in the studied territory. Based on the results of a comparison of the faunas of gastropods from various areas within the whole territory studied and other regions of northern Europe and Western Siberia, it has been shown that the most dramatic reduction in the species composition occurs during the transition from taiga to tundra landscapes.

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Anopheline Mosquito Species Composition, Kdr Mutation Frequency, and Parasite Infectivity Status in Northern Tanzania

Journal of Medical Entomology ◽

10.1093/jme/tjz245 ◽

2020 ◽

Vol 57 (3) ◽

pp. 933-938 ◽

Cited By ~ 1

Author(s):

Eliningaya J Kweka ◽

Humphrey D Mazigo ◽

Lucile J Lyaruu ◽

Emmanuel A Mausa ◽

Nelius Venter ◽

...

Keyword(s):

Species Composition ◽

Malaria Transmission ◽

Malaria Vector ◽

Mosquito Species ◽

Malaria Prevalence ◽

Vector Species ◽

Anopheline Mosquito ◽

Larval Stages ◽

Northern Tanzania ◽

Homozygous Resistant

Abstract The scaling-up of malaria control interventions in northern Tanzania has resulted in a decline in malaria prevalence and vector species composition. Despite this achievement, residual malaria transmission remains a concern in the area. The main aim of this study was to investigate malaria vector species composition, parasite infectivity rates, and the presence of insecticide knockdown resistance (kdr) mutations in three sites that have experienced a significant decline in malaria in northern Tanzania. Adult mosquitoes were sampled using light traps in houses and hand-aspirators in cowsheds, whereas the standard dipping method was used for sampling mosquito larvae. Adult mosquitoes identified as Anopheles gambiae s.l. and An. funestus s.l. and larval stages III and IV of An. gambiae s.l. were stored in absolute ethanol for further laboratory molecular identification. The identified species in the An. gambiae complex were An. gambiae s.s., An. merus, An. quadriannulatus, and An. arabiensis, whereas the An. funestus group comprised An. funestus s.s., An. rivulorum, and An. leesoni. For An. gambiae s.s. analyzed from Zeneth, 47.6% were kdr-East homozygous susceptible, 35.7% kdr-East heterozygous resistant, 9.6% kdr-East homozygous resistant, and 7.1% undefined, whereas specimens from Kwakibuyu were 45.5% kdr-East homozygous susceptible, 32.7% kdr-East heterozygous resistant, 16.3% kdr-East homozygous resistant, and 5.5% undefined. There were no kdr-West alleles identified from any specimen. The overall malaria parasite infectivity rate was 0.75%. No infections were found in Moshi. The findings indicate that populations of the major malaria vector mosquitoes are still present in the study area, with An. funestus taking a lead in malaria transmission.

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Malaria vector species composition and entomological indices following indoor residual spraying in regions bordering Lake Victoria, Tanzania

10.21203/rs.3.rs-27952/v2 ◽

2020 ◽

Author(s):

Charles Elias Kakilla ◽

Alphaxard Manjurano ◽

Karen Nelwin ◽

Jackline Martin ◽

Fabian Mashauri ◽

...

Keyword(s):

Species Composition ◽

Vector Control ◽

Malaria Vector ◽

Lake Victoria ◽

Indoor Residual Spraying ◽

Transmission Risk ◽

Vector Species ◽

Sporozoite Rate ◽

Pirimiphos Methyl ◽

The Impact

Abstract Background: Vector control through long lasting insecticidal nets and focal indoor residual spraying (IRS) is a major component of the Tanzania national malaria control strategy. In mainland Tanzania, IRS has been conducted annually around Lake Victoria basin since 2007. Due to pyrethroid resistance in malaria vectors, use of pyrethroids for IRS was phased out and from 2014 to 2017 pirimiphos-methyl (Actellic® 300CS) was sprayed in regions of Kagera, Geita, Mwanza and Mara. Entomological surveillance was conducted in ten sprayed and four unsprayed sites to determine the impact of IRS on entomological indices related to malaria transmission risk. Methods: WHO Cone bioassays were conducted monthly on interior house walls to determine residual efficacy of pirimiphos-methyl CS. Indoor CDC light traps with or without bottle rotator were hung next to protected sleepers indoors and also set outdoors (un-baited) as a proxy measure for indoor and outdoor biting rate and time of biting. Prokopack aspirators were used indoors to capture potentially resting malaria vector. A sub-sample of Anopheles were tested by PCR to determine species identity and ELISA for sporozoite rate. Results: Annual IRS with Actellic® 300CS from 2015 to 2017 was effective on sprayed walls for a mean of 7 months in cone bioassay. PCR of 2016 and 2017 samples showed vector populations were predominantly An. arabiensis (58.1%, n=4,403 IRS sites, 58%, n=2,441 unsprayed sites). There was a greater proportion of An. funestus s.s. in unsprayed sites (20.4%, n=858) than sprayed sites (7.9%, n=595) and fewer An. parensis (2%, n=85 unsprayed, 7.8%, n=591 sprayed). Biting peaks of An. gambiae s.l. followed periods of rainfall occurring between October and April, but were generally lower in sprayed sites than unsprayed. In most sprayed sites, An. gambiae s.l. indoor densities increased between January and February, i.e. 10-12 months after IRS. The predominant species An. arabiensis had a sporozoite rate in 2017 of 2.0% (95% CI: 1.4-2.9) in unsprayed sites compared to 0.8% (95% CI: 0.5-1.3) in sprayed sites (p=0.003). Sporozoite rates were also lower for An. funestus collected in sprayed sites. Conclusion: This study contributes to the understanding of malaria vector species composition, behavior and transmission risk following IRS around Lake Victoria and can be used to guide malaria vector control strategies in Tanzania.

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Species composition and distribution of marine macro algae at Co To and Thanh Lan archipelago

Tạp chí Khoa học và Công nghệ Biển ◽

10.15625/1859-3097/20/3/15247 ◽

2020 ◽

Vol 20 (3) ◽

pp. 267-276

Author(s):

Dam Duc Tien ◽

Nguyen Thi Mai Anh ◽

Linh Manh Nguyen ◽

Pham Thu Hue ◽

Lawrence Liao

Keyword(s):

Species Composition ◽

Littoral Zone ◽

Marine Algae ◽

Similarity Coefficient ◽

Algal Flora ◽

Average Value ◽

Site Number ◽

Species Composition And Distribution ◽

Total Species ◽

Macro Algae

This paper exhibites species composition and distribution of marine seaweed at 10 sites of Co To and Thanh Lan islands in May 2019. The studies record 76 species of marine algae in the area, belonging to four divisions: Cyanophytes, Rhodophytes, Ochrophytes and Chlorophytes. Among them, five species are classified into Cyanophytes (comprising 6.6% of total species); thirty-four species into Rhodophytes (44.7%); twenty-one species into Ochrophytes/Phaeophytes (27.6%) and sixteen species into Chlorophytes (21.1%). The species composition of marine seaweeds in Co To and Thanh Lan shows significant differences as follows: 22 species (sites number 4 and 10) to 58 species (site number 2) and the average value is 38.7 species per site. Sørensen similarity coefficient fluctuates from 0.33 (sites number 5 and 10) to 0.84 (sites number 1 and 3) and the average value is 0.53. The current investigations show that four species of twenty-one species are collected in the littoral zone and forty-two species in the sub-littoral zone (in which there are thirteen species distributed in both littoral zone and sub-littoral zone). The algal flora in Co To and Thanh Lan is characterized by subtropics.

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