Identification and characterization of immature Anopheles and culicines (Diptera: Culicidae) at three sites of varying malaria transmission intensities in Uganda

Malaria Journal

卷:19

Steve W. Lindsay¹  David L. Smith²  Chris Drakeley³  Grant Dorsey⁴  Melissa D. Conrad⁴  Anne M. Akol⁵  Sarah G. Staedke⁶  Otto Geoffrey⁷  John Rek⁷  Emmanuel Arinaitwe⁷  Maxwell Kilama⁷  Alex K. Musiime⁷  Patrick Kyagamba⁷  Joaniter I. Nankabirwa⁷  Moses R. Kamya⁷ 

[1] Department of Biosciences, Durham University;

[2] Department of Health Metrics Sciences, University of Washington;

[3] Department of Immunology and Infection, London School of Hygiene and Tropical Medicine;

[4] Department of Medicine, San Francisco General Hospital, University of California;

[5] Department of Zoology, Entomology and Fisheries Sciences, College of Natural Sciences, Makerere University;

[6] Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine;

[7] Infectious Diseases Research Collaboration;

关键词: Anopheles;    Culicine;    Anopheline;    Larvae;    Pupae;    Aquatic habitats;   

DOI  :  10.1186/s12936-020-03304-7

来源: DOAJ

【 摘 要 】

Abstract Background Over the last two decades, there has been remarkable progress in malaria control in sub-Saharan Africa, due mainly to the massive deployment of long-lasting insecticidal nets and indoor residual spraying. Despite these gains, it is clear that in many situations, additional interventions are needed to further reduce malaria transmission. The World Health Organization (WHO) has promoted the Integrated Vector Management (IVM) approach through its Global Vector Control Response 2017–2030. However, prior roll-out of larval source management (LSM) as part of IVM, knowledge on ecology of larval aquatic habitats is required. Methods Aquatic habitats colonized by immature Anopheles and culicines vectors were characterized at three sites of low, medium and high malaria transmission in Uganda from October 2011 to June 2015. Larval surveys were conducted along transects in each site and aquatic habitats described according to type and size. Immature Anopheles, culicines and pupae from the described habitats were sampled using standard dipping methods to determine larval and pupae densities. Larvae were identified as anopheline or culicine, and counted. Pupae were not identified further. Binary logistic regression analysis was used to identify factors associated with the presence of immature Anopheles and culicines in each site. Results A total of 1205 larval aquatic habitats were surveyed and yielded a total of 17,028 anopheline larvae, 26,958 culicine larvae and 1189 pupae. Peaks in larval abundance occurred in all sites in March–May and August-October coinciding with the rainy seasons. Anopheles larvae were found in 52.4% (n = 251) of aquatic habitats in Tororo, a site of high transmission, 41.9% (n = 536) of habitats in Kanungu, a site with moderate malaria transmission, and 15.8% (n = 418) in Jinja, a site with low malaria transmission. The odds of finding larvae was highest in rice fields compared to pools in both Tororo (odds ratio, OR = 4.21, 95% CI 1.22–14.56, p = 0.02) and Kanungu (OR = 2.14, 95% CI 1.12–4.07, p = 0.02), while in Jinja the odd were highest in containers (OR = 4.55, 95% CI = 1.09–19.14, p = 0.03). In Kanungu, larvae were less likely to be found in containers compared to pools (OR = 0.26, 95% CI 0.09–0.66, p = 0.008) and river fringe (OR = 0.19, 95% CI 0.07–0.52, p = 0.001). Medium sized habitats were associated with high odds of finding larvae compared to small habitats (OR = 3.59, 95% CI 1.18–14.19, p = 0.039). Conclusions These findings show that immature Anopheles and culicines were common in areas of high and moderate transmission but were rare in areas of low transmission. Although immature Anopheles and culicines were found in all types of water bodies, they were most common in rice fields and less common in open drains and in river fringes. Methods are needed to reduce the aquatic stages of anopheline mosquitoes in human-made habitats, particularly rice fields.

【 授权许可】

Unknown