Risk factors for cutaneous leishmaniasis in the rainforest of Bolivia: a cross-sectional study

Characterizing cutaneous leishmaniasis in a conflict-affected region: a study from North Waziristan, Pakistan

Background/aim

Cutaneous leishmaniasis is an emerging tropical disease that remains a serious public health issue in Pakistan, particularly in North Waziristan. The current research was carried out to investigate the presence of cutaneous leishmaniasis in this region.

Materials and methods

This prospective observational study was conducted from October 2018 to December 2020 at District Head Quarter Hospital Miranshah in North Waziristan with the collaboration of the Pathology Department of Gomal Medical College Dera Ismail Khan, Khyber Pakhtunkhwa. Needle aspirates were used for the microscopic Giemsa-stained slides. SPSS was used for data analysis.

Results

Of the 5406 clinically-suspected cases, 2603(48.2%) were positive by microscopic examination. Of these 2603 patients, 1474 (57%) were male and 1129 (43%) were female. Most of the lesions were on the face, followed by upper and lower limbs. The 5-10-year age group had the highest percentage of 1167 (45%). A single lesion affected 96.6% of the patients, while 2.7% had double lesions and 0.7% had triple lesions. A high number of cutaneous leishmaniasis were seen from April to August, while the lowest number was seen November to December.

Conclusion

This study provides extensive information in relation to the existence of cutaneous leishmaniasis in the North Waziristan district of Pakistan, as well as the detailed demographic features of those affected by the disease.

Why is leptospirosis hard to avoid for the impoverished? Deconstructing leptospirosis transmission risk and the drivers of knowledge, attitudes, and practices in a disadvantaged community in Salvador, Brazil

Several studies have identified socioeconomic and environmental risk factors for infectious disease, but the relationship between these and knowledge, attitudes, and practices (KAP), and more importantly their web of effects on individual infection risk, have not previously been evaluated. We conducted a cross-sectional KAP survey in an urban disadvantaged community in Salvador, Brazil, leveraging on simultaneously collected fine-scale environmental and epidemiological data on leptospirosis transmission. Residents' knowledge influenced their attitudes which influenced their practices. However, different KAP variables were driven by different socioeconomic and environmental factors; and while improved KAP variables reduced risk, there were additional effects of socioeconomic and environmental factors on risk. For example, males and those of lower socioeconomic status were at greater risk, but once we controlled for KAP, male gender and lower socioeconomic status themselves were not direct drivers of seropositivity. Employment was linked to better knowledge and a less contaminated environment, and hence lower risk, but being employed was independently associated with a higher, not lower risk of leptospirosis transmission, suggesting travel to work as a high risk activity. Our results show how such complex webs of influence can be disentangled. They indicate that public health messaging and interventions should take into account this complexity and prioritize factors that limit exposure and support appropriate prevention practices.

Determinants of cutaneous leishmaniasis among students in Delanta district, Northeast Ethiopia: A case-control study

Background and Aims

Cutaneous leishmaniasis (CL) is the most common form of leishmaniasis that causes skin lesions on exposed parts of the body. It is endemic in over 170 districts and highly prevalent in the northern and southern parts of Ethiopia. Thus, the aim of this study was to assess the determinants of CL among students of Wegeltena secondary school in Delanta district, Northeast Ethiopia.

Methods

This unmatched case-control study was conducted from January 4 to 20, 2021 at Wegeltena secondary school. Cases were students who had an active lesion of CL and controls were students who had never been infected with CL (no active lesions). A simple random sampling technique was utilized to select participants in the control group. Data were collected by using a pretested, interviewer-administered structured questionnaire. Bivariable and multivariable logistic regression analyses were performed and variables were declared determinants of CL at a p value of <0.05.

Results

A total of 225 students (58 cases and 167 controls) participated in the study. The mean age of cases and controls was 18.6 (SD ± 0.99 years) and 18.5 years (SD ± 1.17 years), respectively. In this study, 74.1% of cases and 51.5% of controls have been living in rural areas. Furthermore, being male (adjusted odds ratio [AOR] = 4.11; 95% confidence interval [CI]: 1.94-8.69), rural residents (AOR = 2.95; 95% CI: 1.33-6.52), living in areas where caves (AOR = 3.63; 95% CI: 1.24-10.59), nearby forest (AOR = 4.04; 95% CI: 1.42-11.51), and hyrax available (AOR = 2.43; 95% CI: 1.16-5.08) were significantly associated with CL.

Conclusion

In our study, sociodemographic and environmental factors were found to be determinants of CL. Therefore, reducing outdoor activities, wearing protective clothes, use of insecticide-treated nets, and destruction of sand fly breeding sites shall be implemented targeting the rural population that resides in areas where forests, caves, and hyraxes are prominent.

Determinants of anthroponotic cutaneous leishmaniasis by case-control study in Morocco

Leishmaniasis is endemic in Morocco where both cutaneous and visceral forms coexist. To date, anthroponotic cutaneous leishmaniasis (ACL) determinants remain poorly investigated in Morocco. However, the disease risk factors identification is vital to determine the specific preventive process. In this aim, a case-control study was conducted in the main active ACL foci in central Morocco. Epidemiological data were extracted from bulletins, registers and annual reports of the regional direction of Health offices. The socioeconomic and environmental data were collected from epidemiological surveys, completed by a questionnaire intended for accessible positive population and control people selected from the cases' entourage. The study included 258 cases and 395 controls. Our results showed that many socioeconomic factors were associated with ACL in Morocco such as the rural habitation (OR = 4.163; 95% CI: 2.91-5.96), movement to endemic area (OR = 4.53; 95% CI: 3.03-6.77), provenance from leishmaniasis foci (in Essaouira focus OR = 5.34; 95% CI: 1.19-24.03) and poverty. In addition, environmental factors like proximity of vegetation (OR = 2.45; 95% CI: 1.14-5.25), poor domestic hygiene, particularly the absence of sewage system/waste management (OR = 1.63; 95% CI: 1.35-1.96), and presence of animals (OR = 2.67; 95% CI: 1.14-5.25) increase the risk of ACL in Morocco. Except for Matrimonial status (married people, OR = 4.11; 95% CI: 1.80-9.41), there is however no significant association of the disease with the other socio-demographic factors in the study area (p>0.05). These several risk factors must be taken in consideration to prevent this disease through multidisciplinary collaboration and community participation.

Leprosy and cutaneous leishmaniasis affecting the same individuals: A retrospective cohort analysis in a hyperendemic area in Brazil

Background

Leprosy and cutaneous leishmaniasis (CL) are neglected tropical diseases (NTDs) affecting the skin. Their control is challenging but the integration of skin NTDs control programs is recommended to improve timely detection and treatment. However, little is known about the occurrence of leprosy and CL in the same individuals, and what are the characteristics of such patients. This study aimed to identify and characterize patients diagnosed with both leprosy and CL (i.e., outcome) in the hyperendemic state of Mato Grosso, Brazil. Also, we investigated the demographic risk factors associated with the period between the diagnosis of both diseases.

Methodology/principal findings

A retrospective cohort study was conducted with patients diagnosed between 2008 and 2017. From the leprosy (n = 28,204) and CL (n = 24,771) databases of the national reporting system, 414 (0.8%; 414/52,561) patients presenting both diseases were identified through a probabilistic linkage procedure. This observed number was much higher than the number of patients that would be expected by chance alone (n = 22). The spatial distribution of patients presenting the outcome was concentrated in the North and Northeast mesoregions of the state. Through survival analysis, we detected that the probability of a patient developing both diseases increased over time from 0.2% in the first year to 1.0% within seven years. Further, using a Cox model we identified male sex (HR: 2.3; 95% CI: 1.7–2.9) and low schooling level (HR: 1.5; 95% CI: 1.2–1.9) as positively associated with the outcome. Furthermore, the hazard of developing the outcome was higher among individuals aged 40–55 years.

Conclusions/significance

Leprosy and CL are affecting the same individuals in the area. Integration of control policies for both diseases will help to efficiently cover such patients. Measures should be focused on timely diagnosis by following-up patients diagnosed with CL, active case detection, and training of health professionals.

Leprosy and cutaneous leishmaniasis (CL) are neglected tropical diseases (NTDs) that usually affect poor populations in the same geographical areas. Both affect the skin and can cause physical disability and disfigurement resulting in discrimination. Both diseases occur at hyperendemic levels in several regions of Brazil. The integration of skin NTDs control programs may be a way to improve timely detection and treatment. However, little is known about the occurrence of leprosy and CL in the same individuals, and what are the characteristics of these patients. For the Brazilian state of Mato Grosso, we identified 414 patients diagnosed with leprosy and CL between 2008 and 2017, spatially concentrated mainly in the North and Northeast mesoregions. The individual probability of developing both diseases increased from 0.2% to 1.0% within seven years. Male sex, being in the 40–55 years age group, and low levels of schooling were the risk factors positively associated with the time interval between the diagnosis of both diseases. These findings may inform the implementation of integrated leprosy and CL control policies focused on timely diagnosis. A sustainable integration requires continuous measures, such as the follow-up of patients, active case detection, training of health professionals, besides financial and political support.

Characterization of sand fly breeding sites in district Malakand, Khyber Pakhtunkhwa, Pakistan, and evaluation of risk factors for cutaneous leishmaniasis in the region

Present study was carried to determine the sand fly species composition, breeding sites ecology, seasonal abundance, and spatial distribution in district Malakand, Khyber Pakhtunkhwa, Pakistan. In addition, risk factors associated with cutaneous leishmaniasis (CL) were also evaluated. Survey of indoor and outdoor habitats was carried out using sticky traps in 31 villages of Dargai and Batkhela tehsils of Malakand. Soil from habitats of adult and immature sand flies was analysed. Questionnaire-based household survey was also performed in these villages to assess risk factors associated with CL. Soil samples from selected CL positive households were analysed for its contents. Additionally, clinicoepidemiological data from local health centres was examined for the year 2019. Total of 3,140 sand flies belonging to 18 species were collected. Phlebotomus sergenti was the most abundant species (38.16%). Its abundance had a strong positive correlation with mean monthly relative humidity and negative correlation with average temperature. Phlebotomus sergenti and Phlebotomus papatasi were abundant at an elevation ranging from 320 to 1,120 m above sea level and in agricultural lands near human settlements. Flight height preference apparatus collected maximum sand flies at 30 cm (1ft) above the ground and all species associated negatively with height. Soil analysis from habitats of adult and immature flies showed that highest mean number of adults and immatures were recorded from silt loam which carried highest concentrations of K₂ O, Mg, Ca, and Zn. Number of immature sand flies correlated moderately (r = .7, p < .05) with K₂ O soil concentrations. There was significant similarity between organic matter contents in soil samples from positive breeding sites and CL households (Wilcoxon rank-sum test, p = .1976). In multivariate analysis model for CL risk factors, age (26-35 and >35 years), knowledge of leishmaniasis, living in a middle and upper class, preachers visit to villages, and assumption that Afghan refugees are more prone to CL were significant. CL patient's archived data from health centres showed that majority of patients had lesions on face and hands. Patient's influx was highest in February and March.

Epidemiological features of cutaneous leishmaniasis and distribution of sand flies in an endemic area in southeast of Iran

Introduction

Cutaneous leishmaniasis (CL) is a widespread tropical infectious disease in the world. It is one of the most important health problem in Iran which is endemic in different parts of country. This study was conducted to determine epidemiological features of CL and distribution of sand flies in Hajiabad County, one of the important CL foci in southeast of Iran.

Methods

This descriptive cross-sectional study was conducted from March 2019 to March 2020.

All of the suspected CL cases with skin lesions who referred to Hajiabad County health centers and all actively detected patients were clinically and parasitologically examined for CL. Demographic and clinical data of all patients were recorded. Moreover, in this study, sand flies were collected monthly from four typical plain and foothill villages during their active season (May–November) using sticky trap. Sand flies were mounted as permanent microscopic slides, using Puri's medium, and identified by taxonomic keys. Data were analyzed using SPSS.21 software and descriptive statistics.

Results and discussion

A total of 70 confirmed cases of CL were recorded; the incidence rate of the disease was 101 per 100,000 people. The most infected age group was 0–10 years, with a rate of 64.3%. Males were infected more than females and the majority of cases (85.7%) were recorded from rural areas. Most of the cases had 1 lesion (51.4%) and the most lesions (55.8%) were in upper extremities. During the study period, 832 sand fly specimens comprised of ten species of Sergentomyia and seven of Phlebotomus were collected and identified. The most prevalent species was P. papatasi (47.12%), followed by P. alexandri (8.41%) and P. salehi (6.25%). Among the collected Phlebotomus species, P. papatasi and P. sergenti are known as the primary vectors of CL and P. alexandri, P. salehi, and P. caucasicus, play the main role as the secondary vectors of CL in Iran.

Conclusion

This study has revealed that CL is endemic in Hajiabad County and there are five CL vectors that are distributed in this County and some of them are more prevalent in plain areas. These findings can be used as a basis for implementation of interventions toward vector control, which may help in suppression of vector density, and consequently, control of CL in the study area.

SYSTEMATIC REVIEW OF LEISHMANIASIS IN PAKISTAN: EVALUATING SPATIAL DISTRIBUTION AND RISK FACTORS

Both cutaneous (zoonotic cutaneous leishmaniasis [ZCL] and anthroponotic cutaneous leishmaniasis [ACL]) and visceral leishmaniasis (VL) are prevalent in Pakistan, although the cutaneous form is comparatively more widespread. The present study aimed to spatially map different forms of leishmaniasis in Pakistan. In addition, the risk for acquiring leishmaniasis was assessed in different locations of the country. Previously published literature on leishmaniasis distribution and associated risk factors in Pakistan was obtained from PubMed/NCBI and GoogleScholar using specific keywords. Further, 50 articles that focused on geographical distribution and risk factors of the disease in Pakistan were obtained and systematically reviewed. Data regarding location (used in ArcGIS for spatial analysis), number of cases, and risk factors were identified. The present study revealed a high burden of cutaneous leishmaniasis in the northern and western foci of Pakistan. Leishmania major, chiefly a causative agent of ZCL, was observed to be prevalent in the arid and semi-arid climatic zones of the country with elevations between 45 and 2,837 m (maximum number at low elevation). Leishmania tropica cases, associated with ACL, were recorded at elevations ranging from 551 to 2,837 m (majority cases at high elevation). Visceral leishmaniasis (VL) (reportedly caused by Leishmania infantum) was sporadically distributed in the northern areas at elevations 1,432-2,873 m. For VL, particularly, mountainous communities, farming communities, and the presence of dogs were the most commonly reported risk factors. On the other hand, poor preventive measures, migration, presence of domesticated animals, presence of cattle dung, living in mud houses, and outdoor sleeping habits were the principal risk factors associated with cutaneous leishmaniasis (CL). This investigation can guide the health experts and medical entomologists toward targeted and cost-effective surveillance and control of leishmaniasis in Pakistan.

Interaction between environmental and socioeconomic determinants for cutaneous leishmaniasis risk in Latin America

OBJECTIVE

Determine and characterize potential risk areas for the occurrence of cutaneous leishmaniasis (CL) in Latin America (LA).

METHOD

Ecological observational study with observation units defined by municipalities with CL transmission between 2014-2018. Environmental and socioeconomic variables available for at least 85% of the municipalities were used, combined in a single database, utilizing the R software. The principal component analysis methodology was combined with a hierarchical cluster analysis to group clusters of municipalities based on their similarity. The V-test was estimated to define the positive or negative association of the variables with the clusters and separation by natural breaks was used to determine which ones contributed the most to each cluster. Information on cases was also incorporated in the analyses to attribute CL risk for each cluster.

RESULTS

This study included 4,951 municipalities with CL transmission (36.5% of the total in LA) and seven clusters were defined by their association with 18 environmental and socioeconomic variables. The historical risk of CL is positively associated with the Amazonian, Andean and Savannah clusters in a decreasingly manner; and negatively associated with the Forest evergreen, Forest/crop and Forest/populated clusters. The Agricultural cluster did not reveal any association with the CL cases.

CONCLUSIONS

The study made it possible to identify and characterize the CL risk by clusters of municipalities and to recognize the epidemiological distribution pattern of transmission, which provides managers with better information for intersectoral interventions to control CL.

Parasite species variation and impact of spatial displacement of the population on cutaneous leishmaniasis in Rio de Janeiro, Brazil

BACKGROUND

Cutaneous leishmaniasis results from complex interactions between human beings, vectors and the environment. Parasitic species differ in epidemiological and geographical contexts.

METHODS

We studied a retrospective cohort of 696 patients with cutaneous leishmaniasis treated at a reference centre in the state of Rio de Janeiro, Brazil, between 2000 and 2015. We analysed displacements due to work, leisure and migrations with identification of Leishmania species.

RESULTS

The geographic distribution of autochthonous cases showed that >95% of infections occurred in urban areas. In the state of Rio de Janeiro, most cases were concentrated in the cities surrounding forest parks and nature conservation areas. The same applies to the city of Rio de Janeiro, where these infections occurred in the neighbourhoods surrounding some mountain and forest areas. The non-displacement group included 575 (82.6%) patients and the displacement group included 121 (17.4%) patients. Leishmania (Viannia) braziliensis predominated in both groups. Other species were found in the displacement group.

CONCLUSIONS

The disordered urbanization of the state of Rio de Janeiro in recent decades has created conditions for the emergence of urban foci of transmission close to forest areas. Changes in the environment, movement of infected individuals and adaptation of sandflies may have contributed to this.

Cutaneous Leishmaniasis Outbreak Investigation in Hajjah Governorate, Yemen, in 2018: Case-Control Study

Background

Cutaneous leishmaniasis (CL) is endemic in Yemen. About 4440 cases were reported in 2019. On July 23, 2018, a Hajjah governorate surveillance officer notified the Ministry of Public Health and Population about an increase in the number of CL cases in Bani-Oshb, Kuhlan district, Hajjah governorate. On July 24, 2018, Yemen Field Epidemiology Training Program sent a team to perform an investigation.

Objective

We aimed to describe a CL outbreak in Hajjah governorate and determine its risk factors.

Methods

A descriptive study and case-control study (1:1 ratio) were conducted. Cases included people who met the suspected or confirmed case definition of the World Health Organization and lived in Bani-Oshb subdistrict during the period from August 2017 to July 2018. Controls included people living for at least 1 year in Bani-Oshb without new or old skin lesions. Crude odds ratios (cORs) and adjusted odds ratios (aORs) with 95% CI were used to test the significance of associations.

Results

We identified 30 CL cases. Among the 30 patients, 7 (23%) were younger than 5 years, 17 (57%) were 5 to 14 years, 17 (57%) were females, and 23 (77%) had one lesion. The attack rate was 7 per 1000 population in the age group <15 years and 1 per 1000 population in the age group ≥15 years. On bivariate analysis, the following factors were significantly associated with CL: female gender (cOR 5.2, 95% CI 1.7-16.5), malnutrition (cOR 5.2, 95% CI 1.7-16.5), not using a bed net (cOR 14.5, 95% CI 1.7-122.4), poor house lighting (cOR 6.4, 95% CI 2.1-19.7), poor house hygiene (cOR 11.2, 95% CI 3.1-40.7), poor sanitation (cOR 14.5, 95% CI 1.7-122.4), living in houses without window nets (cOR 5.2, 95% CI 1.3-21.2), plantation around the house (cOR 6.5, 95% CI 2.1-20.5), animal barn inside or close to the house (cOR 9.3, 95% CI 1.9-46.7), raising animals (cOR 8.1, 95% CI 1.6-40.7), and having animal dung in or near the house (cOR 6.8, 95% CI 1.7-27.7). The following risk factors remained significant on multivariate stepwise analysis: female gender (aOR 22.7, 95% CI 1.6-320.5), malnutrition (aOR 17.2, 95% CI 1.3-225.8), poor house hygiene (aOR 45.6, 95% CI 2.5-846.4), plantation around the house (aOR 43.8, 95% CI 1.9-1009.9), and raising animals (aOR 287.1, 95% CI 5.4-15205.6).

Conclusions

CL was endemic in Hajjah governorate, and an increase in cases was confirmed. Many individual, housing, and animal related factors were shown to contribute to CL endemicity. Implementation of control measures directed toward altering the factors favoring contact among vectors, reservoirs, and susceptible humans is strongly recommended to control future outbreaks.

[Interaction among environmental and socioeconomic determinants of risk for cutaneous leishmaniasis in Latin AmericaInteração entre os determinantes ambientais e socioeconômicos para o risco de leishmaniose cutânea na América Latina]

OBJECTIVE

Determine and characterize areas at potential risk for the occurrence of cutaneous leishmaniasis (CL) in Latin America.

METHOD

Ecological observational study with observation units defined by municipalities with CL transmission during 2014-2018. Environmental and socioeconomic variables available for at least 85% of municipalities were combined in a single database, using R software. Principal component analysis was combined with hierarchical cluster analysis for the formation of clusters of municipalities according to their similarity. The V-test was used to define positive or negative association of variables with clusters and separation by natural divisions to determine which contributed more to each cluster. Cases were included to attribute CL risk for each cluster.

RESULTS

The study included 4 951 municipalities with CL transmission (36.5% of municipalities in Latin America); seven clusters were defined by their association with 18 environmental and socioeconomic variables. Historical risk of CL is associated positively and in descending order with the Amazonian, Andean, and Savanna clusters; and negatively with the Forest/perennial, Forest/cultivated, and Forest/populated clusters. The Agricultural cluster showed no association with CL cases.

CONCLUSIONS

The study made it possible to identify and characterize CL risk by clusters of municipalities and to understand the characteristic epidemiological distribution patterns of transmission, providing program managers with better information for intersectoral interventions to control CL.

Clinical and immunological characteristics of tegumentary leishmaniasis cases in Bolivia

BACKGROUND

Tegumentary leishmaniasis (TL) is a parasitic disease that can present a cutaneous or mucocutaneous clinical form (CL and MCL, respectively). The disease is caused by different Leishmania species and transmitted by phlebotomine sand flies. Bolivia has one of the highest incidences of the disease in South America and the diagnosis is done by parasitological techniques. Our aim was to describe the clinical and immunological characteristics of CL and MCL patients attending the leishmaniasis reference center in Cochabamba, Bolivia, in order to gain updated clinical and epidemiological information, to evaluate the diagnostic methods used and to identify biomarkers related to clinical disease and its evolution.

METHODOLOGY/PRINCIPAL FINDINGS

The study was conducted from September 2014 to November 2015 and 135 patients with lesions compatible with CL or MCL were included. Epidemiological and clinical data were collected using a semi-structured questionnaire. Two parasitological diagnostic methods were used: Giemsa-stained smears and culture of lesion aspirates. Blood samples obtained from participants were used to measure the concentrations of different cytokines. 59.2% (80/135) were leishmaniasis confirmed cases (CL: 71.3%; MCL: 28.7%). Sixty percent of the confirmed cases were positive by smears and 90.6% were positive by culture. 53.8% were primo-infections. Eotaxin and monokine induced by IFN-γ presented higher serum concentrations in the MCL clinical presentation compared to CL cases and no-cases. None of the cytokines presented different concentrations between primo-infections and secondary infections due to treatment failure.

CONCLUSIONS/SIGNIFICANCE

In Bolivia, parasitological diagnosis remains the reference standard in diagnosis of leishmaniasis because of its high specificity, whereas the sensitivity varies over a wide range leading to loss of cases. Until more accurate tools are implemented, all patients should be tested by both smears and culture of lesion aspirates to minimize the risk of false negatives. Our results showed higher concentrations of several cytokines in MCL compared to CL, but no differences were observed between CL and no-cases. In addition, none of the cytokines differed between primary and secondary infections. These results highlight the need of further research to identify biomarkers of susceptibility and disease progression, in addition to looking at the local cellular immune responses in the lesions.

Gender disparity in cases enrolled in clinical trials of visceral leishmaniasis: A systematic review and meta-analysis

BACKGROUND

A higher caseload of visceral leishmaniasis (VL) has been observed among males in community-based surveys. We carried out this review to investigate how the observed disparity in gender distribution is reflected in clinical trials of antileishmanial therapies.

METHODS

We identified relevant studies by searching a database of all published clinical trials in VL from 1980 through 2019 indexed in the Infectious Diseases Data Observatory (IDDO) VL clinical trials library. The proportion of male participants enrolled in studies eligible for inclusion in this review were extracted and combined using random effects meta-analysis of proportion. Results were expressed as percentages and presented with respective 95% confidence intervals (95% CIs). Heterogeneity was quantified using I2 statistics and sub-group meta-analyses were carried out to explore the sources of heterogeneity.

RESULTS

We identified 135 published studies (1980-2019; 32,177 patients) with 68.0% [95% CI: 65.9%-70.0%; I2 = 92.6%] of the enrolled participants being males. The corresponding estimates were 67.6% [95% CI: 65.5%-69.7%; n = 91 trials; I2 = 90.5%; 24,218 patients] in studies conducted in the Indian sub-continent and 74.1% [95% CI: 68.4%-79.1%; n = 24 trials; I2 = 94.4%; 6,716 patients] in studies from Eastern Africa. The proportion of male participants was 57.9% [95% CI: 54.2%-61.5%] in studies enrolling children aged <15 years, 78.2% [95% CI: 66.0%-86.9%] in studies that enrolled adults (≥15 years), and 68.1% [95% CI: 65.9%-70.0%] in studies that enrolled patients of all ages. There was a trend for decreased proportions of males enrolled over time: 77.1% [95% CI: 70.2%-82.8%; 1356 patients] in studies published prior to the 1990s whereas 64.3% [95% CI: 60.3%-68.2%; 15,611 patients] in studies published on or after 2010. In studies that allowed the inclusion of patients with HIV co-infections, 76.5% [95% CI: 63.8%-85.9%; 5,123 patients] were males and the corresponding estimate was 64.0% [95% CI: 61.4%-66.5% 17,500 patients] in studies which excluded patients with HIV co-infections.

CONCLUSIONS

Two-thirds of the participants enrolled in clinical studies in VL conducted in the past 40 years were males, though the imbalance was less in children and in more recent trials. VL treatment guidelines are informed by the knowledge of treatment outcomes from a population that is heavily skewed towards adult males. Investigators planning future studies should consider this fact and ensure approaches for more gender-balanced inclusion.

Socioeconomic, demographic and landscape factors associated with cutaneous leishmaniasis in Kurunegala District, Sri Lanka

Background

Leishmaniasis is a neglected tropical disease that affects countries in the developing world. In Sri Lanka, cutaneous leishmaniasis is the most common form of the disease. It is prevalent in dry and intermediate zones, mostly associated with rural settings. Understanding basic risk factors is critical in the management of the disease with effective interventions. This study is focused on assessing the demographic, socioeconomic and landscape factors associated with leishmaniasis in Kurunegala District, Sri Lanka.

Methods

A descriptive cross-sectional study was conducted. Households of the past patients and randomly selected households, which had no history of leishmaniasis cases were interviewed. The clinical, socioeconomic, demographic, landscape and awareness-related data were obtained using a pre-tested, interviewer-administered questionnaire.

Results

A total of 101 patients and a similar number of controls were included in the study. All the patients had the cutaneous form of the disease. Housewives and personnel with monthly incomes less than Rs. 10,000 (56.76 USD) were 3.9- and 9.5-times more prone to the disease, respectively, according to multivariate analysis. Presence of decaying garbage, termite hills, unclear areas, wet soil and gardening areas were always associated with the increased odds of acquiring the disease.

Conclusions

Demographic factors do not play a pivotal role in the prevalence of leishmaniasis in the area. Housewives, inhabitants with low incomes and individuals who live in areas with conditions suitable for sand fly breeding and resting are major groups with a higher risk of infection. Special attention must be given in raising awareness and environmental management in control activities.

Androgen-dependent immune modulation in parasitic infection

Parasitic infections modulate the immune system of the host, resulting in either immune tolerance or the induction of pro-inflammatory defense mechanisms against the pathogen. In both cases, sex hormones are involved in the regulation of the immune response, as they are present in the systemic circulation and can act on a wide variety of cell types, including immune cells. Men and women have a different milieu of sex hormones, and these hormones play a role in determining immune responses to parasitic infections. Men, who have higher plasma levels of androgens than women, are generally more susceptible to parasitic infections. Many immune cells express the androgen receptor (AR), and the immunologic functions of these cells can be modulated by androgens. In this review, we will highlight the immune cell types that are sensitive to male steroid hormones and describe their roles during three parasitic diseases, amebiasis, leishmaniasis, and helminthiasis.

Correction to: risk factors for cutaneous leishmaniasis in the rainforest of Bolivia: a cross-sectional study

[This corrects the article DOI: 10.1186/s41182-018-0089-6.].