Influence of landscape heterogeneity on entomological and parasitological indices of malaria in Kisumu, Western Kenya

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Background

Identification and characterization of larval habitats, documentation of Anopheles spp. composition and abundance, and Plasmodium spp. infection burden are critical components of integrated vector management. The present study aimed to investigate the effect of landscape heterogeneity on entomological and parasitological indices of malaria in western Kenya.

Methods

A cross-sectional entomological and parasitological survey was conducted along an altitudinal transect in three eco-epidemiological zones: lakeshore along the lakeside, hillside, and highland plateau during the wet and dry seasons in 2020 in Kisumu County, Kenya. Larval habitats for Anopheles mosquitoes were identified and characterized. Adult mosquitoes were sampled using pyrethrum spray catches (PSC). Finger prick blood samples were taken from residents and examined for malaria parasites by real-time PCR (RT-PCR).

Results

Increased risk of Plasmodium falciparum infection was associated with residency in the lakeshore zone, school-age children, rainy season, and no ITNs ( χ ² = 41.201, df = 9, P < 0.0001). Similarly, lakeshore zone and the rainy season significantly increased Anopheles spp. abundance. However, house structures such as wall type and whether the eave spaces were closed or open, as well as the use of ITNs, did not affect Anopheles spp. densities in the homes ( χ ² = 38.695, df = 7, P < 0.0001). Anopheles funestus (41.8%) and An. arabiensis (29.1%) were the most abundant vectors in all zones. Sporozoite prevalence was 5.6% and 3.2% in the two species respectively. The lakeshore zone had the highest sporozoite prevalence (4.4%, 7/160) and inoculation rates (135.2 infective bites/person/year). High larval densities were significantly associated with lakeshore zone and hillside zones, animal hoof prints and tire truck larval habitats, wetland and pasture land, and the wet season. The larval habitat types differed significantly across the landscape zones and seasonality ( χ ² = 1453.044, df = 298, P < 0.0001).

Conclusion

The empirical evidence on the impact of landscape heterogeneity and seasonality on vector densities, parasite transmission, and Plasmodium infections in humans emphasizes the importance of tailoring specific adaptive environmental management interventions to specific landscape attributes to have a significant impact on transmission reduction.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05447-9.

Related collections

Most cited references 47

Record: found
Abstract: found
Article: not found

Identification of single specimens of the Anopheles gambiae complex by the polymerase chain reaction.

J Scott, W. BROGDON, F Collins (1993)

A ribosomal DNA-polymerase chain reaction (PCR) method has been developed for species identification of individuals of the five most widespread members of the Anopheles gambiae complex, a group of morphologically indistinguishable sibling mosquito species that includes the major vectors of malaria in Africa. The method, which is based on species-specific nucleotide sequences in the ribosomal DNA intergenic spacers, may be used to identify both species and interspecies hybrids, regardless of life stage, using either extracted DNA or fragments of a specimen. Intact portions of a mosquito as small as an egg or the segment of one leg may be placed directly into the PCR mixture for amplification and analysis. The method uses a cocktail of five 20-base oligonucleotides to identify An. gambiae, An. arabiensis, An. quadriannnulatus, and either An. melas in western Africa or An. melas in eastern and southern Africa.

0 comments Cited 648 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

A cocktail polymerase chain reaction assay to identify members of the Anopheles funestus (Diptera: Culicidae) group.

L Koekemoer, L Kamau, R H Hunt … (2002)

Anopheles funestus Giles is a major malaria vector in Africa belonging to a group of species with morphologically similar characteristics. Morphological identification of members of the A. funestus group is difficult because of overlap of distinguishing characteristics in adult or immature stages as well as the necessity to rear isofemale lines to examine larval and egg characters. A rapid rDNA polymerase chain reaction (PCR) method has been developed to accurately identify five members of the A. funestus group. This PCR is based on species-specific primers in the ITS2 region on the rDNA to identify A. funestus (approximately 505bp), Anopheles vaneedeni Gillies and Coetzee (approximately 587bp), Anopheles rivulorum Leeson (approximately 411bp), Anopheles leesoni Evans (approximately 146bp), and Anopheles parensis Gillies (approximately 252bp).

0 comments Cited 280 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: found

Is Open Access

Yaws in the Philippines: first reported cases since the 1970s

Belen Lardizabal Dofitas, Sherjan P. Kalim, Camille B. Toledo … (2020)

Background Yaws is a chronic, highly contagious skin and bone infection affecting children living in impoverished, remote communities and caused by Treponema pallidum subspecies pertenue. The Philippines was thought to be free of yaws following the 1950s eradication campaign but it has been reported in the Liguasan Marsh area, Central Mindanao. This is the first documentation of yaws cases in the Philippines since the 1970s. We describe active and latent yaws recently detected in the Southern Philippines. Case presentation Cross-sectional surveys and screening of skin diseases were conducted in one randomly selected public elementary school per selected municipality in Liguasan Marsh, covering three municipalities per province. Yaws suspects underwent screening and confirmatory serologic tests for Treponema pallidum using Dual Path Platform Syphilis Screen and Confirm Assay (DPP) and Treponema pallidum Particle Agglutination (TPPA). Children with yaws skin lesions and reactive confirmatory tests for T. pallidum and non-treponemal antibodies were considered confirmed yaws cases. Four children aged 5–10 years old had confirmed secondary yaws in Tulunan Municipality, Cotabato Province and in Lambayong Municipality, Sultan Kudarat Province. All had secondary yaws lesions such as moist, cauliflower-like papillomas, thick yellow crusts on pink papules and nodules, whitish, papulosquamous papules and plaques, or hypopigmented patches with small papules on the periphery. Yaws papillomas and erosions were also found on the soles of the feet of one child. The index case had a skin punch biopsy of a partially treated papilloma on his axilla. Histopathological findings showed lichenoid psoriasiform dermatitis with plasma cells, consistent with yaws. Conclusions The clinical, serological, and histopathological confirmation of four yaws cases among children has made the Philippines the 14th country endemic for yaws. This report can help health personnel recognize hidden cases of yaws based on skin signs and serological tests. Yaws remained unrecognized and unreported in the Philippines and in countries previously endemic for yaws probably due to the unsustained integration of the yaws program in the general health services and complacency after the 1950s eradication campaign. Our findings have provided the necessary evidence and stimulus to develop a yaws control and eradication program as one of the country’s neglected tropical diseases.

0 comments Cited 225 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Contributors

Wilfred Ouma Otambo: oumaotambo@gmail.com

Journal

Journal ID (nlm-ta): Parasit Vectors

Journal ID (iso-abbrev): Parasit Vectors

Title: Parasites & Vectors

Publisher: BioMed Central (London )

ISSN (Electronic): 1756-3305

Publication date (Electronic): 27 September 2022

Publication date PMC-release: 27 September 2022

Publication date Collection: 2022

Volume: 15

Electronic Location Identifier: 340

Affiliations

[1 ]GRID grid.442486.8, ISNI 0000 0001 0744 8172, Department of Zoology, , Maseno University, ; Kisumu, Kenya

[2 ]International Centre of Excellence for Malaria Research, Tom Mboya University College-University of California Irvine Joint Lab, Homa Bay, Kenya

[3 ]GRID grid.266093.8, ISNI 0000 0001 0668 7243, Program in Public Health, , University of California Irvine, ; Irvine, CA USA

[4 ]GRID grid.1006.7, ISNI 0000 0001 0462 7212, School of Natural and Environmental Science, , Newcastle University, ; Newcastle, UK

[5 ]GRID grid.10604.33, ISNI 0000 0001 2019 0495, Department of Biology, , University of Nairobi, ; Nairobi, Kenya

[6 ]GRID grid.33058.3d, ISNI 0000 0001 0155 5938, Centre for Global Health Research, Kenya Medical Research Institute, ; Kisumu, Kenya

[7 ]GRID grid.67105.35, ISNI 0000 0001 2164 3847, Department of Pathology, School of Medicine, , Case Western Reserve University, ; Cleveland, OH USA

[8 ]GRID grid.67105.35, ISNI 0000 0001 2164 3847, Centre for Global Health and Diseases, School of Medicine, , Case Western Reserve University, ; Cleveland, OH USA

[9 ]GRID grid.442486.8, ISNI 0000 0001 0744 8172, Department of Biomedical Sciences and Technology, , Maseno University, ; Kisumu, Kenya

Article

Publisher ID: 5447

DOI: 10.1186/s13071-022-05447-9

PMC ID: 9516797

PubMed ID: 36167549

SO-VID: 87ce6194-41ba-4d19-af3f-4138470bf44e

License:

Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

History

Date received : 9 May 2022

Date accepted : 22 August 2022

Funding

Funded by: National Institutes of Health

Award ID: U19 AI129326 and D43 TW001505

Award Recipient : Guiyun Yan

Custom metadata

ScienceOpen disciplines: Parasitology

Keywords: anopheles density,plasmodium infection prevalence,landscape,risk factors

Data availability:

ScienceOpen disciplines: Parasitology

Keywords: anopheles density, plasmodium infection prevalence, landscape, risk factors

Influence of landscape heterogeneity on entomological and parasitological indices of malaria in Kisumu, Western Kenya

Read this article at

Abstract

Background

Methods

Results

Conclusion

Graphical abstract

Supplementary Information

Related collections

Malaria vaccine development

Most cited references 47

Identification of single specimens of the Anopheles gambiae complex by the polymerase chain reaction.

A cocktail polymerase chain reaction assay to identify members of the Anopheles funestus (Diptera: Culicidae) group.

Yaws in the Philippines: first reported cases since the 1970s

Author and article information

Contributors

Journal

Affiliations

Article

History

Funding

Categories

Custom metadata

Comments

Comment on this article

Similar content 63

Cited by 5

Most referenced authors 4,560