Anopheles gambiae s.l (Diptera: Culicidae) seasonal abundance, abdominal status and parity rates in Metema-Armachiho lowland, Northwest Ethiopia

Yibeltal Aschale; Animen Ayehu; Ligabaw Worku; Ayenew Addisu; Ayalew Jejaw Zeleke; Abebe Genetu Bayih; Wossenseged Lemma

doi:10.1186/s12879-020-05068-6

Anopheles gambiae s.l (Diptera: Culicidae) seasonal abundance, abdominal status and parity rates in Metema-Armachiho lowland, Northwest Ethiopia

BMC Infect Dis. 2020 May 11;20(1):333. doi: 10.1186/s12879-020-05068-6.

Authors

Yibeltal Aschale¹, Animen Ayehu², Ligabaw Worku³, Ayenew Addisu⁴, Ayalew Jejaw Zeleke³, Abebe Genetu Bayih⁴, Wossenseged Lemma³

Affiliations

¹ Department of Medical Parasitology, College of Health Sciences, Debre Markos University, P.O. Box: 269, Debre Markos, Ethiopia. yibea33@gmail.com.
² Department of Medical Parasitology, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia.
³ Department of Medical Parasitology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia.
⁴ Director General,Armauer Hansen Research Institute (AHRI), Addis Ababa, Ethiopia.

Abstract

Background: Malaria is a life threating vector borne disease caused by different Plasmodium parasites. Metema and Armachiho are two of the top five malaria endemic areas among the districts of Amhara region in Ethiopia. Transmission pattern is seasonal and migrant laborers who visit these areas for employment in mechanized agriculture are highly affected. The aim of this study was to investigate seasonal abundance, abdominal status and parity rate of An.gambiae s.l in Metema-Armachiho lowlands, Northwest Ethiopia.

Method: A 1 year longitudinal entomological study was conducted in Metema-Armachiho lowlands from June 2016-May 2017. Mosquitoes were collected using CDC-light traps in indoor and outdoor sites for four consecutive days in each month. A total of eight standard battery operated CDC-light traps were used to collect mosquitoes. Female mosquitoes were classed as unfed, fed or gravid under a dissecting microscope. The ovaries of all unfed An.gambiae s.l mosquitoes were examined for evidence of parity. Data were entered and analyzed using SPSS-20 software. Chi-square test was applied to show significant difference between variables. P-value< 0.05 was taken as statistically significant.

Results: Of the total 1253 mosquitoes collected, 713 (552 female, 161 male) were culex and 540 (501 female, 39 male) were An.gambiae s.l. About 50.9% were collected in June-August 2016, 21.7% in September-November 2016, 12.0% in December 2016-February 2017 and 15.4% in March to May 2017. Of the total, 57.2 and 42.8% of the An.gambiae s.l were collected from indoor and outdoor sites respectively. Of the total females collected, 76.8% were unfed; of which 69.4% were parous. Significantly higher number of female An.gambiae s.l were collected in indoor and there was significant difference in abdominal status of An.gambiae s.l mosquitoes collected in different season (P < 0.05).

Conclusions: Highest number of An.gambiae s.l was observed from June-August followed by September-November. The parity rate of An.gambiae s.l was high and there was significant difference in abdominal status of An.gambiae s.l collected in different season.

Keywords: Abdominal status; An.gambiae s.l; Parity; Seasonal abundance.

MeSH terms

Animals
Anopheles* / parasitology
Entomology / methods
Ethiopia / epidemiology
Female
Humans
Longitudinal Studies
Malaria* / epidemiology
Malaria* / parasitology
Malaria* / transmission
Male
Mosquito Vectors* / parasitology
Plasmodium
Seasons*