Cutaneous leishmaniasis in south-western Ethiopia: Ocholo revisited

Community-based treatment of cutaneous leishmaniasis using cryotherapy and miltefosine in Southwest Ethiopia: the way forward?

Background

Cutaneous leishmaniasis (CL) is a common, yet massively underreported skin morbidity in Ethiopia. Most patients never seek treatment, as this is offered only in specialized treatment centers. Early diagnosis and treatment through decentralization is crucial to decrease transmission and to reach the NTD roadmap goals. However, little information is available on outcomes and challenges of community-based treatment initiatives.

Methods

A community-based prospective cohort study was conducted in Ochollo. Patients with clinically or microscopy confirmed CL were included. Cryotherapy was (to be) given weekly with at least four sessions for uncomplicated lesions, and miltefosine was given for 4 weeks for complicated lesions. Miltefosine adherence was assessed by counting pill strips. Clinical and patient-reported outcomes (dermatological life quality index and patient-global assessment) were assessed at month 6 (M6).

Results

A total of 107 patients were included, with a median age of 6 years. Two patients refused, and 15 could not be treated as they were too young (<4 years) for miltefosine. Giving cryotherapy to patients weekly was not feasible due to long wound healing times and required use of topical antibiotics. Only 52.4% of miltefosine patients finished >90% of their tablets by M1. Among 46 patients treated with cryotherapy, 24 (52.2%) were cured at M6, and 9 (19.6%) had substantial improvement. The cure rate was 16/39 (41.0%) for miltefosine with 28.2% (11/39) substantial improvement. Before treatment, more than half (57.8%) of patients reported that CL did not negatively impact their life, which significantly increased to 95.2% at M6. At this time, 61.7% of patients said their lesion was clear, which was 1% before treatment.

Conclusion

Our study is the first to identify the challenges and opportunities of miltefosine and cryotherapy for community treatment of CL. Although overall cure rates were lower than expected, patient-reported outcomes were generally positive and quite some patients had good improvement.

Cutaneous leishmaniasis in Kutaber District, Ethiopia: Prevalence, sand fly fauna and community knowledge, attitude and practices

Background

Cutaneous leishmaniasis (CL) affects 25% of the population living in the highlands of Ethiopia. CL intervention has not decreased the number of leishmaniasis patients. A cross-sectional study was conducted to determine CL prevalence, community's knowledge, attitude and practices (KAP), and the sand fly fauna in Kutaber district, northeast Ethiopia.

Methods

A retrospective, community-based cross-sectional study was conducted in Boru Meda Hospital from December 2014-March 2021 to study CL prevalence of Kutaber district. A Pre-tested, well-structured questionnaire was used to collect data on the participants' socio-demographic characteristics, KAP towards CL and knowledge about sand fly vectors. Chi-square test and logistic regression analysis were used in the study, and data were analyzed using SPSS version 23 (p < 0.05).

Results

A total of 10,002 (14.02%), of which 71,325 samples were confirmed as positive for CL. The infection rate of CL in females (7.1%) was a little bit higher than males (7.0%). More cases were recorded among 15-29 age category. The study also revealed that 77.1% of the respondents had poor knowledge about CL treatment, prevention, clinical presentation and disease transmission. Farmers tended to have poorer knowledge about sand flies than non-workers and students (32.7 vs. 35 and 44.1%; P = 0.049). Housewives had poorer knowledge about sand flies than farmers and workers (22.2 vs. 32.7 and 33.3%; P = 0.023). Phlebotomus longipes comprised the highest composition (80%) of the sand fly species identified in Kutaber district.

Conclusions

The data showed that the community had poor knowledge about CL, vector, and transmission mode. CL preventive measures were prevalent, implying the need to raise CL awareness. Phlebotomus longipes was identified as the most dominant sand fly species which accounted for CL. The findings can be used in developing an effective control strategy to reduce CL transmission in the study area and elsewhere in Ethiopia.

Household knowledge, practice and treatment seeking behaviors towards cutaneous leishmaniasis in the endemic rural communities of Ganta- afeshum district, Tigrai, northern Ethiopia, 2019: a cross-sectional study

BACKGROUND

Cutaneous leishmaniasis is endemic to Ethiopia. However, the prevention and control efforts of leishmaniasis remain unfocused with clear knowledge and practice gaps within the country. Thus, a house to house survey has been carried out to assess the knowledge, practice and treatment-seeking behavior of households towards cutaneous leishmaniasis in the rural communities of Tigrai region, northern Ethiopia.

METHODS

A community-based cross-sectional house-to-house survey was conducted in two selected rural villages of Ganta-afeshum district, Tigrai, northern Ethiopia in 2019. A simple random sampling technique was employed to select the participants. Household heads were interviewed using a pre-tested semi-structured questionnaire. Epi info version 7.0 was used for data entry and the data were imported to SPSS version 23 for analysis. Chi-square test (χ2) was used to test the association between the independent variables and the knowledge and practice status of the study participants. P-value < 0.05 was used to declare a statistically significant association among the variables.

RESULTS

In our study, most of the participants (78%) stated that cutaneous leishmaniasis is a health problem in the area. Three hundred eighty (99.5%) participants responded that the most common clinical presentation of cutaneous leishmaniasis is a lesion on the face. All of the study participants did not know the mode of cutaneous leishmaniasis transmission, and had never heard of the sand fly. A majority of the participants were unaware of the main prevention methods for cutaneous leishmaniasis. Lastly, traditional medicine was used in 90% of the study households with a previous history for cutaneous leishmaniasis.

CONCLUSION

There is a lack of awareness regarding the transmission of cutaneous leishmaniasis in Ganta-afeshum, Ethiopia, where the majority of individuals are unfamiliar with the sand fly vector. Prevention methods for cutaneous leishmaniasis were unavailable among the community. Therefore, health education programs concerning cutaneous leishmaniasis transmission, prevention, and treatment in the area should be rigorously implemented.

Detection of Cutaneous Leishmaniasis Foci in South Ethiopia

Cutaneous leishmaniasis (CL) is a major public health problem in Ethiopia. The disease is endemic in Ochollo, a village in southern Ethiopia, but there are no reports of CL in the wider area, although it is ecologically very similar. We conducted a rapid assessment survey in the South Ethiopian Rift Valley and found 100 parasitologically confirmed CL cases in 38 villages not reported endemic for CL. Approximately half of the cases were children (57%), and most lesions occurred on the face (78%) and were older than 6 months (77%). Only 2% of the people was aware of the mode of transmission, and 9% sought modern treatment at a hospital. These preliminary data indicate that CL is much more widespread than previously reported and that the disease might have a large psychosocial impact. Hence, this study calls for larger surveys across the Ethiopian highlands. Additionally, health education and treatment capacity need to be implemented.

High-resolution habitat suitability model for Phlebotomus pedifer, the vector of cutaneous leishmaniasis in southwestern Ethiopia

BACKGROUND

Phlebotomus pedifer is the vector for Leishmania aethiopica causing cutaneous leishmaniasis (CL) in southwestern Ethiopia. Previous research on the transmission dynamics of CL resulted in recommendations for vector control. In order to target these interventions towards affected areas, a comprehensive understanding of the spatial distribution of P. pedifer at high spatial resolution is required. Therefore, this study determined the environmental predictors that facilitate the distribution of P. pedifer and created a map indicating the areas where conditions are suitable for survival of the vector in southwestern Ethiopia with high spatial resolution.

METHODS

Phlebotomus pedifer presence points were collected during two entomological surveys. Climate, vegetation and topographic variables were assembled. Climate variables were interpolated with variables derived from high-resolution digital elevation models to generate topoclimatic layers representing the climate conditions in the highlands. A Maximum Entropy model was run with the presence points, predicting variables and background points, which were selected based on a bias file.

RESULTS

Phlebotomus pedifer was the only captured Phlebotomus species in the study area and was collected at altitudes ranging between 1685 and 2892 m. Model projections indicated areas with suitable conditions in a 'belt' surrounding the high mountain peaks. Model performance was high, with train and test AUC values being 0.93 and 0.90, respectively. A multivariate environmental similarity surface (MESS) analysis showed that the model projection was only slightly extrapolated for some of the variables. The mean annual temperature was the environmental variable, which contributed most to the model predictions (60.0%) followed by the seasonality in rainfall (13.2%). Variables representing steep slopes showed very low importance to model predictions.

CONCLUSIONS

Our findings indicate that the suitable habitats for P. pedifer correspond well with the altitudes at which CL was reported previously, but the predictions are more widely distributed, in contrast with the description of CL to occur in particular foci. Moreover, we confirm that vector distribution is driven by climate factors, suggesting inclusion of topoclimate in sand fly distribution models. Overall, our model provides a map with a high spatial resolution that can be used to target sand fly control measures in southwestern Ethiopia.

Cutaneous leishmaniasis in north-central Ethiopia: trend, clinical forms, geographic distribution, and determinants

Background

Cutaneous leishmaniasis (CL), being among the neglected tropical diseases, catches little attention despite its considerable influence. This study aimed at estimating the prevalence and associated factors of CL in Boru Meda Hospital, Dessie town, north-central Ethiopia.

Methods

Medical records of patients who attended the Dermatology Department of the Hospital in 2012-May 2018 were assessed. In addition, dermatological patients who were visiting the hospital during the data collection period (November 2017-May 2018) were interviewed to capture socio-demographic, environmental variables, and related factors. The source population was individuals who visited the hospital for skin problems in the stated years and CL positives were the targets. The association between CL and its determinants was tested by logistic regression.

Results

CL prevalence was 1.5% showing increasing trend with the year of examination. Localized, diffused, and mucosal CL was evident across the years. Dessie town had the highest prevalence, 291 (32.8%) patients out of 888 cases. The number of examined (29,701) and positives (543, 1.8%) for males was comparable with females, 28,459 and 345 (1.2%), respectively, increasing with age but without significant difference. Dessie town residence (adjusted odds ratio (AOR) 12.2, 95% confidence interval (CI) 2.2-18.6, p = 0.01), no bed net (AOR 9.9, 95% CI 2.7-16.7, p < 0.01), nearby irrigation (AOR 8.1, 95% CI 1.9-12.4, p < 0.01), and travel to CL endemic areas (AOR 13.9, 95% CI 4.4-14.3, p < 0.01) were significantly associated with CL.

Conclusion

CL is a growing health problem in Dessie and its surroundings. Known risk factors prevail. Comprehensive parasitological, entomological, and social studies are warranted to better manage the disease.

Evaluation of a pan-Leishmania SL RNA qPCR assay for parasite detection in laboratory-reared and field-collected sand flies and reservoir hosts

Background

In eco-epidemiological studies, Leishmania detection in vectors and reservoirs is frequently accomplished by high-throughput and sensitive molecular methods that target minicircle kinetoplast DNA (kDNA). A pan-Leishmania SYBR green quantitative PCR (qPCR) assay which detects the conserved spliced-leader RNA (SL RNA) sequence was developed recently. This study assessed the SL RNA assay performance combined with a crude extraction method for the detection of Leishmania in field-collected and laboratory-reared sand flies and in tissue samples from hyraxes as reservoir hosts.

Methods

Field-collected and laboratory-infected sand fly and hyrax extracts were subjected to three different qPCR approaches to assess the suitability of the SL RNA target for Leishmania detection. Nucleic acids of experimentally infected sand flies were isolated with a crude extraction buffer with ethanol precipitation and a commercial kit and tested for downstream DNA and RNA detection. Promastigotes were isolated from culture and sand fly midguts to assess whether there was difference in SL RNA and kDNA copy numbers. Naive sand flies were spiked with a serial dilution of promastigotes to make a standard curve.

Results

The qPCR targeting SL RNA performed well on infected sand fly samples, despite preservation and extraction under presumed unfavorable conditions for downstream RNA detection. Nucleic acid extraction by a crude extraction buffer combined with a precipitation step was highly compatible with downstream SL RNA and kDNA detection. Copy numbers of kDNA were found to be identical in culture-derived parasites and promastigotes isolated from sand fly midguts. SL RNA levels were slightly lower in sand fly promastigotes (ΔCq 1.7). The theoretical limit of detection and quantification of the SL RNA qPCR respectively reached down to 10⁻³ and 10 parasite equivalents. SL RNA detection in stored hyrax samples was less efficient with some false-negative assay results, most likely due to the long-term tissue storage in absence of RNA stabilizing reagents.

Conclusions

This study shows that a crude extraction method in combination with the SL RNA qPCR assay is suitable for the detection and quantification of Leishmania in sand flies. The assay is inexpensive, sensitive and pan-Leishmania specific, and accordingly an excellent assay for high-throughput screening in entomological research.

Feeding behavior and activity of Phlebotomus pedifer and potential reservoir hosts of Leishmania aethiopica in southwestern Ethiopia

BACKGROUND

Cutaneous leishmaniasis (CL) is a major public health concern in Ethiopia. However, knowledge about the complex zoonotic transmission cycle is limited, hampering implementation of control strategies. We explored the feeding behavior and activity of the vector (Phlebotomus pedifer) and studied the role of livestock in CL transmission in southwestern Ethiopia.

METHODS

Blood meal origins of engorged sand flies were determined by sequencing host DNA. A host choice experiment was performed to assess the feeding preference of P. pedifer when humans and hyraxes are equally accessible. Ear and nose biopsies from livestock were screened for the presence of Leishmania parasites. Sand flies were captured indoor and outdoor with human landing catches and CDC light traps to determine at which time and where P. pedifer is mostly active.

PRINCIPAL FINDINGS

A total of 180 P. pedifer sand flies were found to bite hosts of 12 genera. Humans were the predominant blood meal source indoors (65.9%, p < 0.001), while no significant differences were determined outdoors and in caves. In caves, hyraxes were represented in blood meals equally as humans (45.5% and 42.4%, respectively), but the host choice experiment revealed that sand flies have a significant preference for feeding on hyraxes (p = 0.009). Only a single goat nose biopsy from 412 animal samples was found with Leishmania RNA. We found that P. pedifer is predominantly endophagic (p = 0.003), but occurs both indoors and outdoors. A substantial number of sand flies was active in the early evening, which increased over time reaching its maximum around midnight.

CONCLUSION

In contrast to earlier suggestions of exclusive zoonotic Leishmania transmission, we propose that there is also human-to-human transmission of CL in southwestern Ethiopia. Livestock does not play a role in CL transmission and combined indoor and outdoor vector control measures at night are required for efficient vector control.

Prevalence and environmental determinants of cutaneous leishmaniasis in rural communities in Tigray, northern Ethiopia

Background

In Ethiopia guidelines for diagnoses and treatment of leishmaniases are available, but only a few hundred people are diagnosed and receive treatment. A field study has been carried out to determine the status and environmental determinants of cutaneous leishmaniasis (CL) and assess the degree of awareness of the rural communities in affected areas in Tigray, northern Ethiopia.

Methodology / Principal findings

Following a reconnaissance survey that identified endemic foci, a cross sectional door-to-door survey was conducted in 2009 in five rural communities around the towns of Adigrat and Hagereselam in Tigray. In total 9,622 residents of 1,721 households were clinically screened and household heads interviewed regarding the determinants of infection. The χ² test and logistic regression were used to determine differences in prevalence between localities, age and sex, and to identify environmental determinants of infection.

The overall prevalence of localized CL was 2.3% (highest 4.7%), with marked inter-village differences. Another 20.9% had scars from previous infections. While risk was sex-independent, prevalence was significantly higher in the 0–9 (4.5%) and 10–19 (2.5%) age groups and predominantly involved the face (82.1%) and upper limbs (13.1%). Nearly 11% of the households had one or more cases of CL and this was associated with proximity to hyrax habitats. All interviewees were knowledgeable about the lesions but ignorant of the disease’s mode of transmission and its association with hyraxes.

Conclusions

The study established that CL is an important public health problem in the study communities, and has been so for a while, as demonstrated by the widespread presence of scars. CL in Tigray appeared to be predominantly of zoonotic nature, mainly transmitted in peri-domestic habitats in proximity to hyrax habitats. Integrated interventions, including awareness creation, are highly recommended.

Cutaneous leishmaniasis (CL) is a skin infection, transmitted by sandflies. It is most common in Ethiopia, but so far only a few hundred people have received treatment. Five rural villages in Tigray Region, in the north of Ethiopia, were visited to assess the status and determinants of CL. In a door-to-door survey 9,622 residents of 1,721 households were examined and interviewed. A total of 222 had active lesions, an average prevalence of 2.3% CL. Children (up to 9 years old) and teenagers (age 10–19) were more affected than other groups. Most active lesions were found in the face and on arms. Almost 11% of the households had one or more cases of CL and this was associated with proximity to habitats of hyrax, intermediate hosts of the disease. A total of 2009 people (20.9%) showed scars from earlier infections. The findings show how widespread the disease is in the north of Ethiopia and provide some first insights into the environmental factors that influence transmission.

Ecology and seasonality of sandflies and potential reservoirs of cutaneous leishmaniasis in Ochollo, a hotspot in southern Ethiopia

Background

Ochollo is a village in southern Ethiopia burdened with cutaneous leishmaniasis (CL), where Phlebotomus pedifer is the only vector for Leishmania aethiopica and hyraxes are confirmed reservoir hosts. A detailed description of the different players of transmission, and the ecology and seasonality of the vector needs to be established in order to accomplish efficient control programs.

Methods and findings

Between March 2017 and February 2018, a monthly sandfly collection was carried out in different habitats and records of temperature and humidity were taken. Rodents and hyraxes were trapped in the dry and wet season. All samples were screened for Leishmania kinetoplast DNA (kDNA). Positive samples were further processed for determination of the Leishmania species and the species of the sandfly/small mammal that was found infected. Additionally, the species of 400 sandfly specimens from different habitats and seasons was identified.

17,190 Sergentomyia and Phlebotomus sandflies were caught and showed an overall kDNA prevalence of 2.6%, all were L. aethiopica infections only found in P. pedifer. The overall sandfly and P. pedifer abundance peaked in the dry season and was negatively correlated with the %RH. The kDNA prevalence varied over the months and was negatively correlated with the temperature. Total sandfly abundance did not differ between the sampled habitats, but P. pedifer was the distinct predominant species only in caves. Moreover, significantly more infected sandflies were found in caves. Only 1/192 rodents were kDNA positive, while 20.0% (5/25) of Heterohyrax brucei were found infected.

Conclusions

This study suggests that caves may be a source of multiplication of the infection. If an outdoor control program would be considered, it would be useful to focus on caves in the wet season, when the sandfly abundance is lowest. The captured rodent species appear not important for transmission and the contribution of hyraxes in transmission should be further investigated.

Zoonotic cutaneous leishmaniasis poses a considerable health problem in Ethiopia. Efficient disease control can only be accomplished when all players of transmission are well understood and taken into account. The aim of our study was to investigate in a village in the south, called Ochollo, whether rodents also harbor the parasite and to assess the different potential vector species (sandflies) and their spatial and seasonal distribution. We established that the rodent species we captured are probably no hosts for Leishmania aethiopica, but confirmed that hyraxes are abundant and that a high percentage of them is positive for L. aethiopica. Based on a very large sample size, we found that Phlebotomus pedifer is the only vector in the area. We discovered that the general sandfly and specific P. pedifer abundance are lowest in the wet season and negatively correlated with humidity. We also demonstrated that the sandfly abundance is equally distributed among different habitats, but P. pedifer and infected sandflies mainly reside in caves. Altogether, we suggest that if outdoor sandfly control methods would be considered, it would be useful to carry it out in the wet season in or around caves. The role of hyraxes in disease transmission should be further investigated.

Cutaneous Leishmaniasis Due to Leishmania aethiopica

Leishmania aethiopica is the main causative species for cutaneous leishmaniasis (CL) in Ethiopia. Despite its considerable burden, L. aethiopica has been one of the most neglected Leishmania species. In this review, published evidence on L. aethiopica history, geography, vector, reservoir, epidemiology, parasitology, and immunology is discussed and knowledge gaps are outlined. L. aethiopica endemic regions are limited to the highland areas, although nationwide studies on CL prevalence are lacking. Phlebotomus pedifer and P. longipes are the sandfly vectors and hyraxes are considered to be the main reservoir, but the role of other sandfly species and other potential reservoirs requires further investigation. Where and how transmission occurs exactly are also still unknown. Most CL patients in Ethiopia are children and young adults. Lesions are most commonly on the face, in contrast to CL caused by other Leishmania species which may more frequently affect other body parts. CL lesions caused by L. aethiopica seem atypical and more severe in their presentation as compared to other Leishmania species. Mucocutaneous leishmaniasis and diffuse cutaneous leishmaniasis are relatively common, and healing of lesions caused by L. aethiopica seems to take longer than that of other species. A thorough documentation of the natural evolution of L. aethiopica as well as in depth studies into the immunological and parasitological characteristics that underpin the atypical and severe clinical presentation are needed. Better understanding of CL caused by this parasite species will contribute to interventions related to transmission, prevention, and treatment.

Uncharted territory of the epidemiological burden of cutaneous leishmaniasis in sub-Saharan Africa-A systematic review

INTRODUCTION

Cutaneous leishmaniasis (CL) is the most frequent form of leishmaniasis, with 0.7 to 1.2 million cases per year globally. However, the burden of CL is poorly documented in some regions. We carried out this review to synthesize knowledge on the epidemiological burden of CL in sub-Saharan Africa.

METHODS

We systematically searched PubMed, CABI Global health, Africa Index Medicus databases for publications on CL and its burden. There were no restrictions on language/publication date. Case series with less than ten patients, species identification studies, reviews, non-human, and non-CL focused studies were excluded. Findings were extracted and described. The review was conducted following PRISMA guidelines; the protocol was registered in PROSPERO (42016036272).

RESULTS

From 289 identified records, 54 met eligibility criteria and were included in the synthesis. CL was reported from 13 of the 48 sub-Saharan African countries (3 eastern, nine western and one from southern Africa). More than half of the records (30/54; 56%) were from western Africa, notably Senegal, Burkina Faso and Mali. All studies were observational: 29 were descriptive case series (total 13,257 cases), and 24 followed a cross-sectional design. The majority (78%) of the studies were carried out before the year 2000. Forty-two studies mentioned the parasite species, but was either assumed or attributed on the historical account. Regional differences in clinical manifestations were reported. We found high variability across methodologies, leading to difficulties to compare or combine data. The prevalence in hospital settings among suspected cases ranged between 0.1 and 14.2%. At the community level, CL prevalence varied widely between studies. Outbreaks of thousands of cases occurred in Ethiopia, Ghana, and Sudan. Polymorphism of CL in HIV-infected people is a concern. Key information gaps in CL burden here include population-based CL prevalence/incidence, risk factors, and its socio-economic burden.

CONCLUSION

The evidence on CL epidemiology in sub-Saharan Africa is scanty. The CL frequency and severity are poorly identified. There is a need for population-based studies to define the CL burden better. Endemic countries should consider research and action to improve burden estimation and essential control measures including diagnosis and treatment capacity.

Leishmaniasis in Ethiopia: A systematic review and meta-analysis of prevalence in animals and humans

Leishmaniasis is a neglected tropical disease caused by obligate intracellular protozoa of the genus Leishmania. Ethiopia does not have an overall estimation of prevalence of leishmaniasis infection at a country level. The objective of this systematic review and meta-analysis was to summarize and pool estimates of studies that report the prevalence of leishmaniasis in Ethiopia. The literature search was conducted to identify all published studies reporting the prevalence of leishmaniasis with clearly designed inclusion and exclusion criteria. From all screened articles, 30 studies were eligible for final meta-analysis and systematic review. Because substantial heterogeneity was expected, random-effects meta-analyses were carried out using the total sample size and number of positives to estimate the prevalence of the disease at a country level. Between-study variability was high (τ² = 0.02; heterogeneity I² = 99.72% with Heterogeneity chi-square = 11985.41, a degree of freedom = 33 and P = 0.001). The overall random pooled prevalence of leishmaniasis was 19% (95% CI 14%-24%). Meta-regression analysis showed that diagnosis method used have contributed to the heterogeneity of studies. Molecular diagnosis has significantly lower prevalence than microscopic examination with a coefficient of -0.32, a p-value of 0.024, and CI (-0.6-0.05). The result of effect estimates against its standard error showed there was no publication bias with a P value of 0.084. This review indicated that there is still a higher prevalence of Leishmaniasis in the country. Reporting on risk factors like sex and age affected, species of Leishmania involved and many more other risk factors reviewing was not possible in this study due to lack of completeness in articles included. However, this report is an indication that the country needs nationally coordinated extensive prevention and control plan to reduce public health and socio-economic impact of the disease.

Treatment of Cutaneous Leishmaniasis Caused by Leishmania aethiopica: A Systematic Review

Leishmania aethiopica is the etiological agent of cutaneous leishmaniasis (CL) in Ethiopia and can cause severe and complicated cases such as diffuse CL (DCL), mucocutaneous leishmaniasis or extensive CL, requiring systemic treatment. Despite the substantial burden, evidence-based treatment guidelines are lacking. We conducted a systematic review of clinical studies reporting on treatment outcomes of CL due to L aethiopica in order to help identify potentially efficacious medications on CL that can be taken forward for clinical trials. We identified a total of 24 records reporting on 506 treatment episodes of CL presumably due to L aethiopica. The most commonly used drugs were antimonials (n = 201), pentamidine (n = 150) and cryotherapy (n = 103). There were 20 case reports/series, with an overall poor study quality. We only identified two small and/or poor quality randomized controlled trials conducted a long time ago. There were two prospective non-randomized studies reporting on cryotherapy, antimonials and pentamidine. With cryotherapy, cure rates were 60-80%, and 69-85% with antimonials. Pentamidine appeared effective against complicated CL, also in cases non-responsive to antimonials. However, all studies suffered from methodological limitations. Data on miltefosine, paromomycin and liposomal amphotericin B are extremely scarce. Only a few studies are available on DCL. The only potentially effective treatment options for DCL seem to be antimonials with paromomycin in combination or pentamidine, but none have been properly evaluated. In conclusion, the evidence-base for treatment of complicated CL due to L aethiopica is extremely limited. While antimonials remain the most available CL treatment in Ethiopia, their efficacy and safety in CL should be better defined. Most importantly, alternative first line treatments (such as miltefosine or paromomycin) should be explored. High quality trials on CL due to L aethiopica are urgently needed, exploring group sequential methods to evaluate several options in parallel.

Prevalence and determinants of Leishmania major infection in emerging and old foci in Tunisia

BACKGROUND

Zoonotic Cutaneous Leishmaniasis (ZCL) due to Leishmania major (L. major) is still a serious public health problem in Tunisia. This study aimed to compare the prevalence and risk factors associated with L. major infection in old and new foci using leishmanin skin test (LST) in central Tunisia.

METHODS

A cross sectional household survey was carried out between January and May 2009 on a sample of 2686 healthy individuals aged between 5 and 65 years. We determined the prevalence of L. major infection using the LST. Risk factors of LST positivity were assessed using a logistic regression model.

RESULTS

The overall prevalence of LST positivity was 57% (95% CI: 53-59). The prevalence of L. major infection was significantly higher in the old focus (99%; 95% CI: 98-100) than in the emerging foci (43%; 95% CI: 39-46) (p = <0.001). Multivariate analysis of LST positivity risk factors showed that age, the nature of the foci (old/emerging), personal and family history of ZCL are determinants of positive LST results.

CONCLUSION

The results updated the current epidemiologic profile of ZLC in central Tunisia. Past history of transmission in a population should be considered as a potential confounder in future clinical trials for drugs and vaccines against L. major cutaneous leishmaniasis.

Dermatopathology practice in ethiopia

CONTEXT

Dermatologic diseases are extremely common among the Ethiopian population and are a significant cause of morbidity. However, few studies exist in the literature that describe the incidence and clinical and histologic features of biopsied cutaneous lesions.

OBJECTIVES

To categorize the cutaneous diseases observed in skin biopsies at the All African Leprosy Rehabilitation and Training Center (ALERT) in Addis Ababa, Ethiopia, and to describe the clinical and histologic features of dermatopathologic diagnoses most frequently encountered in this practice setting.

DATA SOURCES

Pathology reports of 2342 cutaneous specimens received at ALERT in Addis Ababa, Ethiopia, were reviewed to determine the range and frequency of cutaneous diseases and dermatoses diagnosed from January 2007 through December 2010.

CONCLUSIONS

The range of cutaneous diseases observed in skin biopsies at ALERT was varied and included inflammatory dermatoses (27%), infectious diseases (24%), and malignant and benign cutaneous neoplasms (22% and 20%, respectively). The most common conditions observed in this study were squamous cell carcinoma (8% of total cases), eczema (6% of total cases), leishmaniasis (6% of total cases), tuberculosis (6% of total cases), and benign nevi (4% of total cases).

The burden of neglected tropical diseases in Ethiopia, and opportunities for integrated control and elimination

Background

Neglected tropical diseases (NTDs) are a group of chronic parasitic diseases and related conditions that are the most common diseases among the 2·7 billion people globally living on less than US$2 per day. In response to the growing challenge of NTDs, Ethiopia is preparing to launch a NTD Master Plan. The purpose of this review is to underscore the burden of NTDs in Ethiopia, highlight the state of current interventions, and suggest ways forward.

Results

This review indicates that NTDs are significant public health problems in Ethiopia. From the analysis reported here, Ethiopia stands out for having the largest number of NTD cases following Nigeria and the Democratic Republic of Congo. Ethiopia is estimated to have the highest burden of trachoma, podoconiosis and cutaneous leishmaniasis in sub-Saharan Africa (SSA), the second highest burden in terms of ascariasis, leprosy and visceral leishmaniasis, and the third highest burden of hookworm. Infections such as schistosomiasis, trichuriasis, lymphatic filariasis and rabies are also common. A third of Ethiopians are infected with ascariasis, one quarter is infected with trichuriasis and one in eight Ethiopians lives with hookworm or is infected with trachoma. However, despite these high burdens of infection, the control of most NTDs in Ethiopia is in its infancy. In terms of NTD control achievements, Ethiopia reached the leprosy elimination target of 1 case/10,000 population in 1999. No cases of human African trypanosomiasis have been reported since 1984. Guinea worm eradication is in its final phase. The Onchocerciasis Control Program has been making steady progress since 2001. A national blindness survey was conducted in 2006 and the trachoma program has kicked off in some regions. Lymphatic Filariasis, podoconiosis and rabies mapping are underway.

Conclusion

Ethiopia bears a significant burden of NTDs compared to other SSA countries. To achieve success in integrated control of NTDs, integrated mapping, rapid scale up of interventions and operational research into co implementation of intervention packages will be crucial.

Local increase of arginase activity in lesions of patients with cutaneous leishmaniasis in Ethiopia

Background

Cutaneous leishmaniasis is a vector-borne disease that is in Ethiopia mainly caused by the parasite Leishmania aethiopica. This neglected tropical disease is common in rural areas and causes serious morbidity. Persistent nonhealing cutaneous leishmaniasis has been associated with poor T cell mediated responses; however, the underlying mechanisms are not well understood.

Methodology/Principal Findings

We have recently shown in an experimental model of cutaneous leishmaniasis that arginase-induced L-arginine metabolism suppresses antigen-specific T cell responses at the site of pathology, but not in the periphery. To test whether these results translate to human disease, we recruited patients presenting with localized lesions of cutaneous leishmaniasis and assessed the levels of arginase activity in cells isolated from peripheral blood and from skin biopsies. Arginase activity was similar in peripheral blood mononuclear cells (PBMCs) from patients and healthy controls. In sharp contrast, arginase activity was significantly increased in lesion biopsies of patients with localized cutaneous leishmaniasis as compared with controls. Furthermore, we found that the expression levels of CD3ζ, CD4 and CD8 molecules were considerably lower at the site of pathology as compared to those observed in paired PBMCs.

Conclusion

Our results suggest that increased arginase in lesions of patients with cutaneous leishmaniasis might play a role in the pathogenesis of the disease by impairing T cell effector functions.

The leishmaniases are a complex of diseases caused by Leishmania parasites. Currently, the diseases affect an estimated 12 million people in 88 countries, and approximately 350 million more people are at risk. The leishmaniases belong to the most neglected tropical diseases, affecting the poorest populations, for whom access to diagnosis and effective treatment are often not available. Leishmania parasites infect cells of the immune system called macrophages, which have the capacity to eliminate the intracellular parasites when they receive the appropriate signals from other cells of the immune system. In nonhealing persistent leishmaniasis, lymphocytes are unable to transmit the signals to macrophages required to kill the intracellular parasites. The local upregulation of the enzyme arginase has been shown to impair lymphocyte effector functions at the site of pathology. In this study, we tested the activity of this enzyme in skin lesions of patients presenting with localized cutaneous leishmaniasis. Our results show that arginase is highly upregulated in these lesions. This increase in arginase activity coincides with lower expression of a signalling molecule in lymphocytes, which is essential for efficient activation of these cells. These results suggest that increased arginase expression in the localized cutaneous lesions might contribute to persistent disease in patients presenting with cutaneous leishmaniasis.

A zoonotic focus of cutaneous leishmaniasis in Addis Ababa, Ethiopia

BACKGROUND

Cutaneous leishmaniasis (CL) is endemic in the highlands of Ethiopia, and almost always caused by Leishmania aethiopica. Hitherto, Addis Ababa (the capital city of Ethiopia) was not considered endemic for CL, mainly due to absence of epidemiological and field ecological studies. This report summarizes the preliminary epidemiological investigation that proved the existence of active transmission in southeastern Addis Ababa.

RESULTS

Active case finding surveys were conducted in 3 localities, Saris, Kality, and Akaki, which are found in and around Bulbula-Akaki river gorges. During the surveys conducted in January 2005 - May 2006, a total of 35 cases with 9 active and 26 healed skin lesions were identified. Eighteen of the cases (51.4%) were found in Saris; while 10 (28.6%) and 7 (20%) cases were from Kality and Akaki respectively.Ten colonies of rock hyraxes (Heterohyrax brucei) were identified in the vicinities of the 3 localities. Three of the 48 hyraxes (6.3%) trapped from the surroundings harbored natural infections of Leishmania aethiopica. Confirmation of the Leishmania species of the 3 isolates was achieved by PCR amplification and RFLP analysis of the ribosomal DNA internal transcribed spacer (ITS) sequences. Based on sandfly species composition and proximity of resting sites to human settlements, Phlebotomus longipes is circumstantially proven to be the vector of CL in south east Addis Ababa.

CONCLUSION

The study proves the existence of isolated zoonotic foci of CL in south eastern Addis Ababa, with P. longipes as the likely vector and H. brucei as the natural reservoir host.

Cutaneous leishmaniasis, Sri Lanka

Cutaneous leishmaniasis (CL) is an emerging disease in Sri Lanka. Of 116 patients with clinical symptoms suggestive of CL, 86 were confirmed positive for Leishmania donovani. Most patients had single dry lesions, usually on the face. Patients were from 5 of the 7 agroclimatic zones in Sri Lanka.

Cutaneous leishmaniasis, Sri Lanka

In 50 healthy Peruvian shantytown residents, zinc cream applied to tuberculosis skin-test sitescaused a 32% increase in induration compared with placebo cream. Persons with lower plasma zinc had smaller skin-test reactions and greater augmentation with zinc cream. Zinc deficiency caused false-negative skin-test results, and topical zinc supplementation augmented antimycobacterial immune responses enough to improve diagnosis.

Leishmania (Kinetoplastida): Species typing with isoenzyme and PCR–RFLP from cutaneous leishmaniasis patients in Ethiopia

Cutaneous leishmaniasis (CL) is an increasing public health problem in Ethiopia. There is a concern that it is spreading with increased incidence. In this study, we used isoenzyme electrophoresis and internal transcribed spacer one (ITS1) PCR-RFLP techniques to identify Leishmania species from CL patients in Ethiopia. We obtained isolates from 55 localized cutaneous leishmaniasis (LCL), 3 diffused cutaneous leishmaniasis (DCL) and 36 biopsy samples from 34 LCL and 2 DCL cases from All Africa Leprosy and Tuberculosis Rehabilitation and Training Center (ALERT) and clinically diagnosed CL cases from Ochollo village. Both isoenzyme and ITS1 PCR-RFLP techniques showed that Leishmania aethiopica (L. aethiopica) was the aetiologic agent in all cases. Our study also showed that ITS1 PCR-RFLP could identify Leishmania species from biopsy samples and suggests the method could be used for epidemiological surveillance of leishmaniasis in Ethiopia and for species-specific diagnosis.

Tegumentary leishmaniasis in childhood

Very little has been published about tegumentary leishmaniasis in children and there are many controversies about this disorder in the literature. Therefore, we discuss the pathogenesis, clinical aspects, means to diagnosis, and treatment of this endemic disease.

A new sandfly species, Phlebotomus (Larroussius) ashfordi (Diptera, Psychodidae) from Ethiopia, previously confused with P. (L.). aculeatus

The sandfly subgenus Phlebotomus (Larroussius) contains species which transmit parasites causing cutaneous and visceral leishmaniasis in East Africa, including Ethiopia. The Gewasha caves in central Ethiopia harbour a new species (Phlebotomus ashfordi) belonging to the subgenus Larroussius and previously identified as P. (L.) aculeatus Lewis, Minter and Ashford. Although generally similar to P. (L.) aculeatus and P. (L.) elgonensis Ngoka, Madel and Mutinga, the species is distinct in eight male characters and in the female spermatheca. Given its taxonomic affinity to known vectors of cutaneous leishmaniasis and the presence of disease in the Gewasha caves area, the medical importance of this species needs to be assessed.

Detection of cutaneous Leishmania infection in paraffin-embedded skin biopsies using the polymerase chain reaction

In this study the polymerase chain reaction (PCR) with previously developed oligonucleotide primers was used to detect Leishmania aethiopica in paraffin-embedded skin biopsy specimens. The Leishmania-specific 120 base pair fragment of the kinetoplast deoxyribonucleic acid (kDNA) minicircles has been amplified from all parasitologically or histologically confirmed cases of cutaneous leishmaniasis (CL), as demonstrated by gel electrophoresis and hybridization with L. aethiopica kDNA. Control specimens from patients with skin diseases other than CL were all negative. Using PCR, Leishmania were demonstrated in the skin lesions of 7 cases in a group of 40 patients in whom the parasites could not be demonstrated by histopathology or culture in vitro although lesions were clinically suggestive of CL. These data indicate that PCR, carried out on DNA extracted from formalin-fixed and paraffin-embedded tissue specimens, is a valuable method for the diagnosis of CL, especially in chronic cases where the parasite load in the lesion is low.

Phlebotomine sandflies of Kenya (Diptera: Psychodidae). III. The identification and distribution of species of the subgenus Larroussius

The six species of phlebotomine sandflies of the subgenus Larroussius recorded in Kenya are Phlebotomus aculeatus, P. elgonensis, P. guggisbergi, P. longipes, P. orientalis and P. pedifer. Five are proven vectors of leishmaniasis in that country or elsewhere. Males of all six can be identified by the morphology of the aedeagus or the number and position of the hairs on the inner surface of the coxite. Additional features separating some of the species are the sizes of the palpal and antennal segments. The females have usually been considered difficult or impossible to distinguish. A comparison of the base of the spermathecal ducts is made and it is shown that all six can be identified by this character alone. A map of Kenya is given, showing the presently known distribution of the six Larroussius species. Further surveys are necessary in parts of the country that have not been systematically surveyed.