Sero-prevalence of Leishmania donovani infection in labour migrants and entomological risk factors in extra-domestic habitats of Kafta-Humera lowlands - kala-azar endemic areas in the northwest Ethiopia

Abstract

BackgroundVisceral leishmaniasis (VL) or kala-azar cases in seasonal labour migrants from highland areas are addressed to travel history to the Metema–Humera lowlands, northwestern Ethiopia. Factors that affect the incidence of VL in extra-domestic habitats were not evaluated. The aim of this study was to evaluate sero-prevalence of Leishmania donovani infection in randomly selected labour migrant workers and entomological risk factors which might affect the incidence of kala-azar.MethodsSero-prevalence of L. donovani infection in labour migrants was obtained from Direct Agglutination Test (DAT) using blood samples. Logistic regression analysis was used to correlate the possible risk factors with L. donovani infection. The season for L. donovani infection or Phlebotomus orientalis bite was estimated from the study of population dynamic of P. orientalis in areas where the blood was sampled.ResultA total of 7, 443 P. orientalis (1,748 female and 5,695 male) were collected from agricultural fields and thickets of Acacia seyal using 461 CDC light traps. The highest mean number of P. orientalis/trap in the thickets of A. seyal and agricultural fields were 46.9 and 43.9 in March and April respectively. The mean P. orientalis/trap for November – May dry season in agricultural fields (11.39) and thickets of A. seyal (25.30) were higher compared to 0.66 in fields and 3.92 in thickets during June – August weeding season. Of the total 359 labour migrants screened using DAT, 45 (12.5%) were DAT-positive (≥1:800) for L. donovani infections. Very high titers (1:12800) were found in 3 (0.8%) individuals who had the risk of kala-azar development. Statistically significant p-values and odd ratio (OR) for staying in the areas both in the weeding and harvesting seasons (p = 0.035; OR = 2.83) and sleeping in the agricultural fields (p = 0.01; OR = 15.096) were positively correlated with L. donovani infection. Night harvest (p = 0.028; OR = 0.133) and knowledge about sign or symptoms (p = 0.042; OR = 0.383) were negatively associated with this infection.ConclusionsSleeping in open agricultural fields was related with L. donovani infections in labour migrants during June-August weeding season.

Impact of high malaria incidence in seasonal migrant and permanent adult male laborers in mechanized agricultural farms in Metema – Humera lowlands on malaria elimination program in Ethiopia

“…But, there is no an easy access for treatment in remote agriculture fields and when they are crossing Ethiopian border to work in Gadarif states. Malaria transmission in the seasonal laborers could also be enhanced due to outdoor activities of the laborers especially during harvest time of sesame which is performed at night [9]. President Malaria Initiative (PMI) working in Malaria Elimination Program of Ethiopia has reported the existence of an ongoing research to better understand malaria transmission among migrant workers [5].…”

Leishmaniasis: A Review on Parasite, Vector and Reservoir Host

“…Human activities such as deforestation, agricultural development and settlements near forested areas and domestication of animals are reasons for occurrence of both zoonotic and anthroponotic transmissions of leishmaniasis [59]. Hence, control and elimination of leishmaniasis largely depends on the understanding of how leishmaniasis involves various mammalian reservoir hosts, whose epidemiological role is yet to be fully understood [60,61]. Epidemiological investigations should not only target human cases, but also focus on animal reservoir and their transmissibility competences [24,57,62,63].…”

Zoonotic impact and epidemiological changes of leishmaniasis in Ethiopia

“…The main foci are found in the lowland areas of north, northwestern, and southwestern Ethiopia, with some sporadic cases in the central-east part of the country (Kassahun et al, 2015a). Northern lowland foci are Metema and Humera plains in the Tigray and Amhara regional states, bordering Sudan and Eritrea, constitute the main VL endemic areas, contributing over 60 % of the total burden in the country (Dawit et al, 2013;Leta et al, 2014;Lemma et al, 2015). The other main focus in the southwest is in the lower course of the Rift Valley, most notably, the Segen (Aba Roba focus) and Weyto Valleys in the drainage basin of the Chew Bahir Lake, near Konso Woreda.…”

“…Social and political forces, especially military activities and agricultural development projects are major drivers of VL endemicity and new epidemics in Ethiopia (Leta et al, 2014;Lemma et al, 2015;Al-Salem et al, 2016). The population movements probably lead to alterations in the number, range and density of the vectors and reservoirs consequently.…”

“…The agricultural activities such as weeding and harvest of sesame and sorghum in Humera, western lowlands Tigray attract around 200,000 seasonal labor migrants annually, mainly from the surrounding Amhara and Tigray highland areas. In this endemic region, VL particularly affects migrant workers (Dawit et al, 2013;Lemma et al, 2015).…”