Climate change and environmental influence on visceral leishmaniasis in West Pokot county, Kenya

Abstract

Kala-azar is a parasitic disease caused by Leishmania species transmitted by sand fly. In Kenya, kala-azar is endemic in thirty sub-counties spread over in eleven counties in the arid zones. Climate change-influenced seasonal weather variability and environmental alterations remain important determinants of many vector-borne diseases. The present study focused on climate change and environmental influence on kala-azar in West Pokot. Descriptive cross-sectional and retrospective research design was adapted. Study area was purposively selected. Locations and villages were randomly selected, while households were systematically selected. Three hundred sixty three household questionnaires, eleven key informant interviews, and five focus group discussions were undertaken. Secondary data was obtained from Kacheliba sub-county hospital records. Statistical package for social science version 24 was used to analyze quantitative data while NVivo software was used to analyse qualitative data. Kala-azar cases have been on the rise on aggregate from 2010 to 2020, 400 to 500 annual average cases, and incident rate tends to surge during dry season and just after the rains when humidity is high and temperature variations are wide. Significant environmental characteristics associated with risk of kala-azar infection included: presences of seasonal rain water pathways and rock piles around houses (X2= 30.706, df=1, p<0.001); presence of acacia trees in and around homesteads (X2=21.404, df=1, p<0.001); presence of dumping site (X2=9.641, df=1, p=0.002); presence of anthills around the homesteads (X2=16.538, df=1, p<0.001); presence of animal shed (X2=4.290, df=1, p=0.038); presences of chicken shelter (X2=36.862, df=1, p<0.001); and practices of frequently moving houses to new temporary compound (X2=20.919, df=1, p<0.001). Climate change-induced seasonal weather variability; increased temperature and reduced precipitation and environmental alterations remain significant predictors of kala-azar in West Pokot. Community sensitization on disease prevalence, clearing of vector predilection sites and improving community environmental risk perception are imperative to promote prevention and reduce disease burden.Brief summaryClimate change and environmental alteration influence on vector-borne diseases is getting stronger as ever increasing global temperatures and human activity-induced environmental changes remain key drivers of vector expansion and disease re-emergence. In Kenya, kala-azar cases are on an increasing trend as annual incidents surpassed 1,500 with a growing list of over eleven endemic counties. The present study used household questionnaire, interrogated surrounding environment using observation checklist and delved into Kacheliba hospital records. Risk of kala-azar was significant in association with presence of seasonal water pathways, presence of acacia trees, anthills, cattle & goat and chicken shelters around houses. On aggregate, kala-azar incident rate was increasing from 2010 to 2020, and cases tend to surge towards end of first and start of last quarter annually. These surge periods coincide with dry season and just after rains in the area when the humidity is high. Apparently during the last 10 years there seems reduced precipitation and increase temperature. Interestingly, increased in temperature and reduced precipitation was associated with increased reported Kala-zar cases. Policy makers and concerned agencies should consider promoting preventive behaviors, increasing community risk perception and eliminating vector-harboring structures around houses, while observing environmental conservation as a disease mitigation strategy.

Visceral Leishmaniasis (Kala-azar) in Merti Sub-County, Isiolo County: A Case of Socio-Cultural Challenges

“…These results are consistent with research findings of a study conducted by Abdullahi et al (2022) on climate change and environmental influence on Kala-azar in West Pokot County which reported a surge of Kala-azar cases during the dry seasons and just after the rains when the region experienced high humidity. These findings corroborate earlier reports and further attribute the rise in Kala-azar cases during the dry season to elevated vector populations and vector expansion to uncommon areas towards the end of dry seasons, which are typically characterized by high humidity and wider temperature variations.…”

“…Similar to this, prolonged customary drought conditions brought on by climate change cause pasture coverage to diminish, which in turn leads to increased migration of people and animals further into rangeland sections with high vector densities in search of pasture and browsing material for their livestock. This migration exposes people to vector bites, as reported in earlier studies (Abdullahi et al, 2022).…”