Leishmaniasis is a serious and often fatal neglected tropical disease (NTD) which mainly affects the poorest of the poor and is associated with malnutrition, population displacement, poor housing, and a weak immune system [
It is endemic in 98 countries with greater than 350 million people at risk: an estimated 700 000-1.2 million new cases, 600 000 to 1 million added new cases annually of cutaneous, 50 000 to 90 000 new cases of visceral leishmaniasis, and about 20,000 to 40,000 deaths from the disease each year [
In Ethiopia, VL mainly occurs in the arid and semiarid areas; however, recent reports indicate spreading of the disease to areas where it was previously nonendemic [
An estimated 4,500 to 5000 new cases of VL occur per year and over 3.2 million people are at risk of infection in the country [
The study was conducted at Kahsay Abera Hospital in Humera town (Figure
Western Tigray map showing the study area.
A retrospective descriptive study was conducted using the hospital admission database, which includes all patients who were diagnosed with leishmaniasis to estimate the incidence of six-year data from Kahsay Abera Hospital’s annual disease report database.
The study was conducted on all patients admitted who have been suspected of having leishmaniasis infection and tested for rK39-based immune chromatographic test (ICT) at Kahsay Abera Hospital in Humera town from January 2012 to December 2017. Potential risk factors for leishmaniasis infection in human were collected from the hospital, which included categorical variables: age (0-4, 5-14, and ≥15 years), sex (male vs. female), origin of place (came from highland to agricultural fields vs. permanently living in and around Humera), clinical forms of leishmaniasis (visceral vs. cutaneous), mortality rates, and the occurrence of infections (harvesting time from July to December vs. dry time from January to June according to format of hospital).
Data were coded, checked, and uploaded into Microsoft Excel 2010 spreadsheet computer program and analyzed using STATA version 11.0 for Windows (Stata Corp., College Station, USA). Univariate and binary logistic regression performed utilizing the same program for the first set of questions included sex, age, season, and origin. 95% confidence intervals were computed and a P value
Ethical approval was obtained from Aksum University Shire Campus, Research and Ethical Review Committee. Consent was also sought from the hospital administration before being involved.
A total of 26511 hospital discharged patients with diagnosis of leishmaniasis were identified, out of which 2232 (8.42%) human leishmaniasis cases were registered and from these cases, 71 were dead from January 2012 to December 2017. The results showed that leishmaniasis cases decreased across the study years with the highest recorded in 2014. Mortality rates of leishmaniasis were 18 (3.3%) in 2012, 16 (3.1%) in 2013, 15 (2.4%) in 2014, 8 (3.3%) in 2015, 9 (4.1%) in 2016, and 5 (5.4%) in 2017 (Figure
Trends of leishmaniasis in relation to age and sex.
Year | Demographic | No. of cases | Percent | |
---|---|---|---|---|
2012 | Age in years | 0-4 | 74 | 13.6 |
5 to 14 | 85 | 15.6 | ||
≥15 | 387 | 70.8 | ||
Total | 546 | 100 | ||
Sex | Female | 74 | 13.6 | |
Male | 472 | 86.4 | ||
Total | 546 | 100 | ||
| ||||
2013 | Age | 0-4 | 58 | 11.4 |
5 to 14 | 60 | 11.8 | ||
≥15 | 392 | 76.9 | ||
Total | 510 | 100 | ||
Sex | Female | 63 | 12.4 | |
Male | 447 | 87.6 | ||
Total | 510 | 100 | ||
| ||||
2014 | Age | 0-4 | 29 | 4.7 |
5 to 14 | 104 | 16.9 | ||
≥15 | 484 | 78.4 | ||
Total | 617 | 100 | ||
Sex | Female | 39 | 6.3 | |
Male | 578 | 93.7 | ||
Total | 617 | 100 | ||
| ||||
2015 | Age | 0-4 | 22 | 9.0 |
5 to 14 | 24 | 9.8 | ||
≥15 | 199 | 81.2 | ||
Total | 245 | 100 | ||
Sex | Female | 27 | 11.0 | |
Male | 218 | 89.0 | ||
Total | 245 | 100 | ||
| ||||
2016 | Age | 0-4 | 22 | 9.9 |
5 to 14 | 25 | 11.3 | ||
≥15 | 175 | 78.8 | ||
Total | 222 | 100 | ||
Sex | Female | 38 | 17.1 | |
Male | 184 | 82.9 | ||
Total | 222 | 100 | ||
| ||||
2017 | Age | 0-4 | 2 | 2.2 |
5 to 14 | 6 | 6.5 | ||
≥15 | 84 | 91.3 | ||
Total | 92 | 100 | ||
Sex | Female | 3 | 3.3 | |
Male | 89 | 96.7 | ||
Total | 92 | 100 |
Trends of leishmaniasis in Kahsay Abera Hospital from 2012 to 2017.
Highest occurrences of the cases were those admitted during harvesting time from July to December compared to dry time from January to June in all the study years. The highest incidence of leishmaniasis was found in workers who came from highland to agricultural fields compared to those who permanently lived in and around Humera in all six years (Table
Trends of leishmaniasis in relation to season and origin.
Year | Season and origin | No. of cases | Percent | |
---|---|---|---|---|
2012 | Season | Dry time | 241 | 44.14 |
Weeding and harvesting time | 305 | 55.86 | ||
Total | 546 | 100 | ||
Origin | Lowland | 248 | 45.4 | |
Highland | 298 | 54.6 | ||
Total | 546 | 100 | ||
| ||||
2013 | Season | Dry time | 207 | 40.59 |
Weeding and harvesting time | 303 | 59.41 | ||
Total | 510 | 100 | ||
Origin | Lowland | 232 | 45.5 | |
Highland | 278 | 54.5 | ||
Total | 510 | 100 | ||
| ||||
2014 | Season | Dry time | 282 | 45.71 |
Weeding and harvesting time | 335 | 54.29 | ||
Total | 617 | 100 | ||
Origin | Lowland | 201 | 32.6 | |
Highland | 416 | 67.4 | ||
Total | 617 | 100 | ||
| ||||
2015 | Season | Dry time | 97 | 39.6 |
Weeding and harvesting time | 148 | 60.4 | ||
Total | 245 | 100 | ||
Origin | Lowland | 96 | 39.2 | |
Highland | 149 | 60.8 | ||
Total | 245 | 100 | ||
| ||||
2016 | Season | Dry time | 89 | 40.1 |
Weeding and harvesting time | 133 | 59.9 | ||
Total | 222 | 100 | ||
Origin | Lowland | 99 | 44.6 | |
Highland | 123 | 55.4 | ||
Total | 222 | 100 | ||
| ||||
2017 | Season | Dry time | 30 | 32.61 |
Weeding and harvesting time | 62 | 67.39 | ||
Total | 92 | 100 | ||
Origin | Lowland | 35 | 38 | |
Highland | 57 | 62 | ||
Total | 92 | 100 |
The likelihood of infection was also significantly higher in the group greater than 15 years in all the study years. Univariate analysis of the infection rate of leishmaniasis was based on the potential risk factors and found higher male infection rates than female (P <0.05) in all the study years (Table
Incidence of leishmaniasis in relation to age and sex with all diagnosed patients for leishmaniasis.
Year | Risk factors | Admitted | No. of cases | Percent | OR (95% CI) | P value | |
---|---|---|---|---|---|---|---|
2012 | Age | 0-4 | 910 | 74 | 8.13 | 1.63 (1.11, 2.72) | <0.000 |
5 to 14 | 908 | 85 | 9.36 | ||||
≥15 | 1240 | 387 | 31.20 | ||||
Total | 3058 | 546 | 17.85 | ||||
Sex | Female | 1418 | 74 | 5.22 | 1.7(1.42-2.35) | <0.000 | |
Male | 1640 | 472 | 28.78 | ||||
Total | 3058 | 546 | 17.85 | ||||
| |||||||
2013 | Age | 0-4 | 1016 | 58 | 5.71 | 1.8 (1.45, 2.80) | <0.000 |
5 to 14 | 1009 | 60 | 5.95 | ||||
≥15 | 1577 | 392 | 24.86 | ||||
Total | 3602 | 510 | 14.16 | ||||
Sex | Female | 1685 | 63 | 3.74 | 1.9( 1.1, 3.6) | <0.000 | |
Male | 1917 | 447 | 23.32 | ||||
Total | 3602 | 510 | 14.16 | ||||
| |||||||
2014 | Age | 0-4 | 1103 | 29 | 2.63 | 1.93 (1.3, 2.96) | <0.000 |
5 to 14 | 1352 | 104 | 7.69 | ||||
≥15 | 1821 | 484 | 26.58 | ||||
Total | 4276 | 617 | 14.42 | ||||
Sex | Female | 1230 | 39 | 3.17 | 1.81(1.00, 3.45) | <0.000 | |
Male | 3046 | 578 | 17.98 | ||||
Total | 4276 | 617 | 14.42 | ||||
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2015 | Age | 0-4 | 1600 | 22 | 1.38 | 1.67(1.01, 2.02) | <0.000 |
5 to 14 | 1680 | 24 | 1.43 | ||||
≥15 | 1707 | 199 | 11.66 | ||||
Total | 4987 | 245 | 4.91 | ||||
Sex | Female | 2665 | 27 | 1.01 | 1.89(1.2,2.80) | <0.000 | |
Male | 2322 | 218 | 9.39 | ||||
Total | 4987 | 245 | 4.91 | ||||
| |||||||
2016 | Age | 0-4 | 1494 | 22 | 1.47 | 1.91 (1.08, 2.72) | <0.000 |
5 to 14 | 1582 | 25 | 1.57 | ||||
≥15 | 1706 | 175 | 10.26 | ||||
Total | 4782 | 222 | 4.64 | ||||
Sex | Female | 2393 | 38 | 1.60 | 1.5(1.0. 2.52) | <0.000 | |
Male | 2389 | 184 | 7.70 | ||||
Total | 4782 | 222 | 4.64 | ||||
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2017 | Age | 0-4 | 1706 | 2 | 0.11 | 1.6 (1.1, 1.50) | <0.03 |
5 to 14 | 1838 | 6 | 0.33 | ||||
≥15 | 2262 | 84 | 3.71 | ||||
Total | 5806 | 92 | 1.60 | ||||
Sex | Female | 2710 | 3 | 0.11 | 1.4(0.98, 1.27) | <0.04 | |
Male | 3096 | 89 | 2.87 | ||||
Total | 5806 | 92 | 1.60 |
Incidence of leishmaniasis in relation to season and origin with all diagnosed patients for leishmaniasis.
Year | Risk factors | Admitted | No. of cases | Percent | OR (95% CI) | P value | |
---|---|---|---|---|---|---|---|
2012 | Season | Dry time | 1650 | 241 | 14.60 | 1.54(1.4, 2.52) | <0.01 |
Weeding and harvesting time | 1408 | 305 | 21.66 | ||||
Total | 3058 | 546 | 17.85 | ||||
Origin | Lowland | 2001 | 248 | 13.39 | 1.8(0.94, 2.92) | <0.000 | |
Highland | 1057 | 298 | 28.19 | ||||
Total | 3058 | 546 | 17.85 | ||||
| |||||||
2013 | Season | Dry time | 1837 | 207 | 11.27 | 1.4(0.85,1.99) | <0.000 |
Weeding and harvesting time | 1765 | 303 | 17.17 | ||||
Total | 3602 | 510 | 14.16 | ||||
Origin | Lowland | 2423 | 232 | 9.57 | 1.9 (0.84, 2.92) | <0.000 | |
Highland | 1179 | 278 | 23.58 | ||||
Total | 3602 | 510 | 14.16 | ||||
| |||||||
2014 | Season | Dry time | 2450 | 282 | 11.51 | 1.5(1.22, 1.97) | <0.003 |
Weeding and harvesting time | 1826 | 335 | 18.35 | ||||
Total | 4276 | 617 | 14.43 | ||||
Origin | Lowland | 2651 | 201 | 7.58 | 1.9 (1.40, 3.01) | <0.000 | |
Highland | 1625 | 416 | 25.60 | ||||
Total | 4276 | 617 | 14.43 | ||||
| |||||||
2015 | Season | Dry time | 2870 | 97 | 3.38 | 1.45(1.11, 1.83) | <0.02 |
Weeding and harvesting time | 2117 | 148 | 6.99 | ||||
Total | 4987 | 245 | 4.91 | ||||
Origin | Lowland | 2985 | 96 | 3.22 | 1.6(1.7, 2.23) | <0.000 | |
Highland | 2002 | 149 | 7.44 | ||||
Total | 4987 | 245 | 4.91 | ||||
| |||||||
2016 | Season | Dry time | 2575 | 89 | 3.46 | 1.6(1.6, 2.02) | <0.001 |
Weeding and harvesting time | 2207 | 133 | 6.03 | ||||
Total | 4782 | 222 | 4.64 | ||||
Origin | Lowland | 2866 | 99 | 3.45 | 1.8 (1.6, 2.18) | <0.000 | |
Highland | 1916 | 123 | 6.42 | ||||
Total | 4782 | 222 | 4.64 | ||||
| |||||||
2017 | Season | Dry time | 2930 | 30 | 1.02 | 1.3(0.75, 1.6) | <0.04 |
Weeding and harvesting time | 2876 | 62 | 2.16 | ||||
Total | 5806 | 92 | 1.85 | ||||
Origin | Lowland | 3501 | 35 | 1.00 | 1.5(1.1, 1.9) | <0.001 | |
Highland | 2305 | 57 | 2.47 | ||||
Total | 5806 | 92 | 1.85 |
The study provided a 6-year review of the epidemiological trends and all hospital discharged patients only to diagnose leishmaniasis in Humera. A total of 2232 human leishmaniasis cases were registered and the incidence of leishmaniasis was decreased across the study years. The reason could be mainly due to the fact that the government of Ethiopia, particularly Tigray regional state, has developed its own control strategies so as to limit the rapid spread of the disease. A national leishmaniasis task force was established in 2007 with the aim of eliminating VL and hospitals and health centers in endemic regions equipped to treat VL include Kahsay Abera Humera Hospital, Aksum Hospital, and Mekelle Hospital in Tigray regional state [
According to available data in the Kahsay Abera Hospital, the disease was distributed in the various age groups, but occurred most frequently in the age group of greater than 15 years old (P<0.000). It might be due to the fact that matured migrant agricultural workers are highly exposed to sandfly. According to Leta
Univariate analysis revealed that being male was a risk for leishmaniasis exposure in all the study years. This gender difference might be due to difference in outdoor activity between males and females. This might be associated with activities of males in that they engage in outdoor activities such as weeding and harvesting sesame which will make them more accessible to the sandfly bite while females are more likely to remain indoors due to sociocultural factors. Similarly, sleeping under an acacia tree during the day and habitually sleeping outside at night are associated with significantly increased risk [
Humera and its surrounding areas have significant economic input for the country because cash crops such as sesame, cotton, and sorghum are grown at a commercial scale. Thousands of male migrant workers arrive every year during the agricultural season (June–November). More than 80% of patients with VL were male migrant workers infected with
People who come from highlands of Tigray and Amhara regions for weeding and harvesting sesame are at higher risk of leishmaniasis infection as compared to those living permanently in and around Humera. People who came from highlands are highly exposed to sandfly due to sleeping in the farm and camp outside the house. The reason might be due to the fact that epidemics of VL are often associated with migration and the introduction of nonimmune people into areas with existing transmission cycles and most of the migrants are living outside the home. Lemma
There was statistically significant difference between infection rate and seasons in all the study years. It may be due to the fact that labor migrants are most probably exposed to leishmaniasis during June–August weeding season and staying during September–October harvest season. Epidemic outbreaks were common during weeding and harvesting times. In weeding and harvesting season, workers sleep outside the house and they could not use bed nets. Gadisa
Male labor migrants older than 15 years of age from highlands are the most probably exposed to leishmaniasis during June–August in the weeding season and during September–October in the harvesting season. This might be due to sleeping in the farm and camp outside the house leading to being more accessible to the sandfly bite. Therefore, awareness creation on the risks of sleeping outdoors and the impact of using of bed nets is imperative especially for male labor migrants from the highlands during weeding and harvesting season.
Cutaneous leishmaniasis
Visceral leishmaniasis.
All data generated or analyzed during this study are included in this published article. The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.
The authors declare that they have no conflicts of interest.
Dawit Gebremichael Tedla carried out designing the research and preparing the proposal, data gathering, analyzing the data, and preparing the manuscript. Fsahatsion Hailemariam Bariagabr and Hagos Hadgu Abreha carried out reviewing, editing, and organizing the papers. All authors read and approved the final manuscript.
We are grateful to Kahsay Abera Hospital staffs for their support. We also thank Aksum University for facilitating and partially funding this study.