# Cutaneous Leishmaniasis in Tigray, Ethiopia: Clinical patterns, environmental drivers and public health implications

## TL;DR

This study investigates the spread and risk factors of cutaneous leishmaniasis in Tigray, Ethiopia, revealing high prevalence and environmental-behavioral drivers.

## Contribution

The study provides the first detailed epidemiological data on cutaneous leishmaniasis in Tigray, identifying risk factors and disease patterns.

## Key findings

- Cutaneous leishmaniasis prevalence in Tigray is 12.7%, with 4.5% active lesions and 8.2% scars.
- Facial lesions and multiple lesions per individual are common, contrasting with global CL patterns.
- Environmental factors like proximity to hyraxes and bats, and poor housing, are significant risk factors.

## Abstract

Cutaneous leishmaniasis (CL) is a vector-borne skin disease caused by the bite of female sandflies infected with the Leishmania parasite and is widely distributed in the highlands of Tigray, Northern Ethiopia. However, despite its widespread distribution, little is known about the actual epidemiology of the disease in Tigray and Ethiopia as a whole. Therefore, this study aimed to document the epidemiology, risk factors and public health implications of CL in Tigray, Ethiopia.

Between March and May 2022, a cross-sectional household survey was conducted in seven districts of Tigray, Northern Ethiopia, using multistage sampling technique. Participants were clinically examined for scars and/or active lesions and samples taken from active lesions were investigated for parasite amastigotes by microscopy. Data on socio-demographic characteristics and environmental determinants were documented using semi-structured questionnaires. Bivariate and multivariate logistic regressions were used to identify risk factors associated with CL infections.

A total of 3,817 individuals (48.2% males and 51.8% females) residing in 927 households were screened and included in the study. A total of 484 individuals showed clinical evidence of CL infection (13.7% of all males, 11.5% of all females). The overall prevalence was found to be 12.7% (4.5% active lesions, 8.2% scars). Active cases were predominantly localized cutaneous leishmaniasis (LCL) (85%) but a substantial number of mucocutaneous (MCL) cases (11%) and diffused (DCL) (4%) types were also identified. The highest rates of active lesions (5.2%) were found in children aged 1–14 years. Most lesions (69%) occurred on the face, and 51.4% of cases had ≥ 2 lesions. Of the study sites screened, Emba Alaje district had the highest prevalence (15.7%). Cases clustered in highland zones (70.2% at 2,300–3,200 m altitude; 93% at 2,000–3,000 m). Significant host risk factors included age, outdoor sleeping and poor housing (cracked walls). Moreover, proximity to hyraxes, bats, caves, or animal burrows were identified among the significant environmental risk factors (p < 0.05).

Cutaneous leishmaniasis is an underprioritized yet serious public health challenge in Tigray, driven by environmental and behavioral factors. Several forms of the disease (LCL, MCL and DCL) are prevalent in the region, with children and young adults being the most affected. Advocacy for regional recognition of CL, integration of CL control into existing NTD programmes is recommended. Targeted interventions for high-risk groups, enhanced surveillance and mapping, vector and reservoir control measures, community awareness and healthcare capacity and a One Health approach are highly recommended—for sustainable control of CL in Tigray, Ethiopia.

Cutaneous leishmaniasis (CL) is one of the most overlooked of the neglected tropical diseases which is widely distributed in the highlands of Tigray, Northern Ethiopia. However, despite its widespread distribution, little is known about the actual epidemiology of the disease in the region. In this study, we examined the epidemiology, risk factors and public health implications of CL in Tigray. Our findings indicate that CL represents a serious public health burden in the region, with an overall prevalence of 12.7% (4.5% active lesions, 8.2% scars) and all three forms of the disease localized (LCL), mucocutaneous (MCL) and diffuse (DCL) are very prevalent. Notably, most lesions in Tigray occurred on the face, this predominance of facial lesions in Northern Ethiopia, contrasts with other CL hotspots globally. More than half of CL cases had two or more lesions per individual; but, the reason why most lesions on the face and why many cases in Ethiopia acquired ≥2 lesions needs further investigation. In the present study, all CL cases were exclusively found at altitudes between 1,997-3,164 meters above sea level. Significant host risk factors included age, outdoor sleeping and poor housing (cracked walls) and environmental risk factors such as proximity to hyraxes, bats, caves, or animal burrows within a 300-m radius were significantly associated—suggesting both outdoor and indoor transmission. Targeted interventions for high-risk groups, vector and reservoir control measures and community awareness are crucial measures needed—for sustainable control of CL in Tigray and other endemic regions in Ethiopia, towards delivering targets set out in the WHO Roadmap for NTDs (2021–2030).