Risk factors for cutaneous leishmaniasis in Cukurova region, Turkey

Genetic diversity in Leishmania infantum and Leishmania tropica isolates from human and canine hosts in northern Morocco

This study investigated nine provinces in northern Morocco and collected 275 skin scraping, 22 bone marrow aspirates, and 89 fine needle aspirations from suspected cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) patients and potentially infected dogs. Molecular analysis using ITS1 RFLP PCR and RT-PCR revealed a higher prevalence of L. infantum (66.18 %; χ2 = 28.804; df = 1; P-value = 8.01e-08) than L. tropica in skin scraping, with L. infantum being the sole causative agent for both VL and canine leishmaniasis. L. infantum was predominantly found in most provinces, while L. tropica was relatively more dominant in Taza Province. Discriminant Analysis of Principal Components (DAPC) revealed distinct clustering between L. tropica and the other three species. However, no small subset of SNPs could clearly differentiate between Infantum_CL, Infantum_VL, and CanL, as they likely share a significant genetic background. The high rate of L. infantum could be attributed to the abundance of sand fly species transmitting VL. In Taza Province, Phlebotomus sergenti, responsible for anthroponotic CL, is the most abundant species. DNA sequencing demonstrated sequence heterogeneity in L. infantum (variants 1-9) and L. tropica (variants 1-7). Phylogenetic analysis showed a distinct separation between L. tropica and L. infantum strains, with an overlap among L. infantum strains isolated from cutaneous, visceral, and canine cases, and dogs serving as the central population for L. infantum.

A disfiguring neglected tropical disease sweeps war-torn Yemen: a community-based study of prevalence and risk factors of cutaneous leishmaniasis among rural communities in the western highlands

BACKGROUND

Cutaneous leishmaniasis (CL) is a major health problem in Yemen and is endemic in many rural areas across the country.

METHODS

A community-based cross-sectional survey followed by unmatched case-control comparisons was conducted among 612 participants in Utmah district, western Yemen. A total of 223 participants were included in the case-control analysis to identify the significant risk factors. Skin scrapping samples were examined by microscopy and internal transcribed spacer 1 nested polymerase chain reaction.

RESULTS

Overall, 33% (202/612) of the participants had active skin lesions and/or scars that met the clinical criteria for CL. A total of 90 (14.7%) participants had suspected active CL lesions; however, a prevalence of 8.7% (53/612) was obtained based on molecular and parasitological examination, with Leishmania tropica being the only causative agent identified. Multivariable logistic regression analyses showed that being ≤10 y old, being female, living in houses with cracked walls, living in the presence of other family members with typical ulcerating skin diseases and sleeping outside were factors significantly associated with an increased likelihood of having CL. Moreover, keeping livestock on the ground floor of the house was significantly associated with a decreased likelihood of having CL.

CONCLUSION

The study reveals an alarmingly high prevalence of CL among the studied population. Therefore there is an urgent need for effective control measures and improved treatment efforts against this devastating disease.

Effects of cattle on vector-borne disease risk to humans: A systematic review

Vector-borne pathogens (VBPs) causing vector-borne diseases (VBDs) can circulate among humans, domestic animals, and wildlife, with cattle in particular serving as an important source of exposure risk to humans. The close associations between humans and cattle can facilitate the transmission of numerous VBPs, impacting public health and economic security. Published studies demonstrate that cattle can influence human exposure risk positively, negatively, or have no effect. There is a critical need to synthesize the information in the scientific literature on this subject, in order to illuminate the various ecological mechanisms that can affect VBP exposure risk in humans. Therefore, the aim of this systematic review was to review the scientific literature, provide a synthesis of the possible effects of cattle on VBP risk to humans, and propose future directions for research. This study was performed according to the PRISMA 2020 extension guidelines for systematic review. After screening 470 peer-reviewed articles published between 1999-2019 using the databases Web of Science Core Collection, PubMed Central, CABI Global Health, and Google Scholar, and utilizing forward and backward search techniques, we identified 127 papers that met inclusion criteria. Results of the systematic review indicate that cattle can be beneficial or harmful to human health with respect to VBDs depending on vector and pathogen ecology and livestock management practices. Cattle can increase risk of exposure to infections spread by tsetse flies and ticks, followed by sandflies and mosquitoes, through a variety of mechanisms. However, cattle can have a protective effect when the vector prefers to feed on cattle instead of humans and when chemical control measures (e.g., acaricides/insecticides), semio-chemicals, and other integrated vector control measures are utilized in the community. We highlight that further research is needed to determine ways in which these mechanisms may be exploited to reduce VBD risk in humans.

Cutaneous Leishmaniasis Prevalence and Clinical Overview: A Single Center Study from Saudi Arabia, Eastern Region, Al-Ahsa

Cutaneous leishmaniasis (CL) is a vector-borne parasitic disease that is transmitted via the bites of infected female sandflies. CL has been endemic in several countries worldwide for many decades, and numerous cases have been reported in Saudi Arabia, particularly across six regions; one of which is AL-Ahsa. Our research aimed to evaluate the epidemiological situation of CL among the patients in Al-Ahsa, Eastern region, Kingdom of Saudi Arabia, during the period from 2017 to 2023. The data were collected from the patients' registries and included 245 patients who were diagnosed with CL in Al-Ahsa, Saudi Arabia. Fewer than half of the cases (47.8%) were Saudi patients, with a significant number of them being males (84.5%). Over half of the cases (52.7%) were aged between 21 and 40 years, and about three-quarters (74.7%) of the cases resided in rural areas. Regarding the nature of the lesions, 38.4% of the cases had one lesion, which was mainly distributed on a lower extremity (62.0%) or an upper extremity (52.2%). A high percentage of the lesions (75.2%) were wet lesions and caused by L. major. Concerning risk factors, a greater number of patients (71.4%) had been in rural areas within the last three months. Additionally, more than half of the cases (54.3%) had close contact with rodents, followed by birds (28.2%), sheep (22.0%), dogs (16.3%), and other animals (1.2%). The results showed a low number of reported CL cases in 2020 and 2021, followed by a surge in 2022 and 2023. The study shows that cutaneous leishmaniasis is still a public health problem in Al-Ahsa and is primarily associated with rural areas.

Cutaneous Leishmaniasis: Associated Risk Factors and Prevention in Hubuna, Najran, Saudi Arabia

Background

Many countries are currently affected by leishmaniasis, and cutaneous leishmaniasis is ranked among the ten most neglected diseases. The aim of this study was to determine the risk factors related to cutaneous leishmaniasis and preventive measures among people living in Hubuna, Najran, Saudi Arabia.

Methods

A community-based cross-sectional survey was conducted from January to October 2022. A convenience sampling technique was used, with 396 individuals invited to participate in the current study and 391 included. A self-administered questionnaire was utilized for collecting data. Descriptive analysis was used for risk factors and preventive measures, while χ² tests were used for determining associations with risk factors.

Results

Among participants, 38.1% (n=149) reported having cutaneous leishmaniasis clinically diagnosed and under treatment. Age 0-10 years was found to be associated significantly with cutaneous leishmaniasis infection (AOR 3.08, 95% CI 1.6-6.4; P=0.002) compared to other groups. A significant association was noted too for those residing in/around planted areas versus those who were not (AOR 1.18, 95% CI 0.13-2.24; P<0.001). In terms of occupation, farming was significantly associated with cutaneous leishmaniasis (AOR 2.54, 95% CI 1.15-3.76; P=0.010). No significant associations were observed in regard to sex (AOR 1.4, 95% CI 0.7-1.6; P=0.11), education (P=0.072), or preventive measures used (P>0.05).

Conclusion

The cutaneous leishmaniasis endemicity level in Hubuna was high. Several socioeconomic and environmental factors contribute enormously to the spread of the disease in the area. Further investigation of risk factors of cutaneous leishmaniasis all over the country and setting up appropriate interventions to prevent its spread are recommended.

Analysis of associated risk factors among recurrent cutaneous leishmaniasis patients: A cross-sectional study in Khyber Pakhtunkhwa, Pakistan

BACKGROUND

Leishmaniasis is the second and fourth highest cause of mortality and morbidity respectively among all tropical diseases. Recurrence in the onset of leishmaniasis is a major problem that needs to be addressed to reduce the case fatality rate and ensure timely clinical intervention. Here we are investigating the association of risk factors with recurrent cutaneous leishmaniasis to address this issue.

MATERIAL AND METHODS

Patients received by Nasser Ullah Khan Babar Hospital in Peshawar, Pakistan from March 2019 to July 2020 were enrolled in this study. Those patients who developed symptoms after completion of treatment were included in Group-A while those who had atypical scars like leishmaniasis but were negative for cutaneous leishmaniasis were included in the comparison group tagged as Group B. All those individuals who had completed six weeks of treatment for CL but had normal complete blood counts (CBC) were included to avoid other underlying immunological pathologies, while we excluded those participants who had co-morbidities like diabetes, liver disease, cardiac disease, and pregnant and lactating women through their history Association was tested between Group-A and Group-B with other explanatory variables through chi-square test. The regression model was proposed to determine the predictors.

RESULT

A total of 48 participants of both sexes were included in the study with a mean age of 32.2 ± 15.10. The data suggest that females are overrepresented among the patients with recurrent leishmaniasis [21(53.8 %,); p = 0.07]. Compared to patients; healthy participants had a higher proportion of adults (19-59 years) versus adolescents (13-18 years) [26(66.7 %) vs 07(17.9), p = 0.004]. Multivariate logistic regression analysis shows that females are 2.1 times more prone to infections among cases as compared to healthy individuals [unadjusted OR 2.20, 95 % confidence interval (CI) 1.5-10.6, p = 0.02; adjusted OR 2.1, 95 % CI 1.50-10.69, p = 0.02]. We propose that patients receiving intradermal were less likely to be infected as compared to those receiving intralesional injections [unadjusted OR 0.07.0, 95 % confidence interval (CI) 1.18-3.37, p = 0.03; adjusted OR 0.06, 95 % CI 1.18-3.38, p = 0.03].

CONCLUSION

Old age (adults) and sex (females) were the strongest predictors to be associated with recurrent leishmaniasis. Similarly, the choice of intradermal as compared to intralesional injection and the prolonged treatment duration were strongly associated with greater chances of recurrence.

Cutaneous Leishmaniasis: A 2022 Updated Narrative Review into Diagnosis and Management Developments

This review is an update of an earlier narrative review published in 2015 on developments in the clinical management of cutaneous leishmaniasis (CL) including diagnosis, treatment, prevention and control measurements. CL is a vector-borne infection caused by the protozoan parasite Leishmania. The vector is the female sandfly. Globally, CL affects 12 million cases and annually 2 million new cases occur. CL is endemic in almost 100 countries and the total risk population is approximately 350 million people. WHO lists CL an emerging and uncontrolled disease and a neglected tropical disease. Local experience-based evidence remains the mainstay for the management of CL. Whereas intralesional therapeutic options are the first treatment option for most CL patients, those with mucocutaneous and disseminated involvement require a systemic therapeutic approach. Moreover, different Leishmania species can vary in their treatment outcomes. Therefore, species determination is critical for optimal CL clinical management. New DNA techniques allow for relatively easy Leishmania species determination, yet they are not easily implemented in resource-limited settings. There is a desperate need for novel, less toxic, and less painful treatment options, especially for children with CL. Yet, the large and well conducted studies required to provide the necessary evidence are lacking. To further control and potentially eliminate CL, we urgently need to improve vector control, and diagnostics, and we require efficient and safe vaccines. Alas, since CL primarily affects poor people, biotechnical companies dedicate little investment into the research programs that could lead to diagnostic, pharmaceutical, and vaccine innovations.

A Review on Climate, Air Pollution, and Health in North Africa

PURPOSE OF REVIEW

The aim of this review is to summarize and provide clear insights into studies that evaluate the interaction between air pollution, climate, and health in North Africa.

RECENT FINDINGS

Few studies have estimated the effects of climate and air pollution on health in North Africa. Most of the studies highlighted the evidence of the link between climate and air pollution as driving factors and increased mortality and morbidity as health outcomes. Each North African country prioritized research on a specific health factor. It was observed that the health outcome from each driving factor depends on the studied area and data availability. The latter is a major challenge in the region. As such, more studies should be led in the future to cover more areas in North Africa and when more data are available. Data availability will help to explore the applicability of different tools and techniques new to the region. This review explores studies related to climate and air pollution, and their possible impacts on health in North Africa. On one hand, air quality studies have focused mainly on particulate matter exceedance levels and their long-term exposure impacts, namely, morbidity and mortality. The observed differences between the various studies are mainly due to the used exposure-response function, the studied population, background emissions, and natural emission from the Sahara Desert that characterize the region. On the other hand, climate studies have focused primarily on the impact of heat waves, vector-borne disease, and mental disorders. More than half of these studies have been on leishmaniasis disease. The review revealed unbalanced and insufficient research on health impacts from air pollution episodes and climate extremes across the region.

The effect of climate variables on the incidence of cutaneous leishmaniasis in Isfahan, Central Iran

In recent years, there have been considerable changes in the distribution of diseases that are potentially tied to ongoing climate variability. The aim of this study was to investigate the association between the incidence of cutaneous leishmaniasis (CL) and climatic factors in an Iranian city (Isfahan), which had the highest incidence of CL in the country. CL incidence and meteorological data were acquired from April 2010 to March 2017 (108 months) for Isfahan City. Univariate and multivariate seasonal autoregressive integrated moving average (SARIMA), generalized additive models (GAM), and generalized additive mixed models (GAMM) were used to identify the association between CL cases and meteorological variables, and forecast CL incidence. AIC, BIC, and residual tests were used to test the goodness of fit of SARIMA models; and R² was used for GAM/GAMM. 6798 CL cases were recorded during this time. The incidence had a seasonal pattern and the highest number of cases was recorded from August to October. In univariate SARIMA, (1,0,1) (0,1,1)₁₂ was the best fit for predicting CL incidence (AIC=8.09, BIC=8.32). Time series regression (1,0,1) (0,1,1)₁₂ showed that monthly mean humidity after 4-month lag was inversely related to CL incidence (AIC=8.53, BIC=8.66). GAMM results showed that average temperature with 2-month lag, average relative humidity with 3-month lag, monthly cumulative rainfall with 1-month lag, and monthly sunshine hours with 1-month lag were related to CL incidence (R²=0.94). The impact of meteorological variables on the incidence of CL is not linear and GAM models that include non-linear structures are a better fit for prediction. In Isfahan, Iran, meteorological variables can greatly predict the incidence of CL, and these variables can be used for predicting outbreaks.

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.

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.

Cutaneous Leishmaniasis in Pakistan: a neglected disease needing one health strategy

Background

Cutaneous Leishmaniasis (CL) is a neglected tropical disease, which mainly affects poor communities. It is one of the major vector-borne disease and endemic in Pakistan.

Methods

A case-control study to evaluate potential risk factors of human-CL was conducted in Khewra region, District Jhelum, Pakistan from January–April 2014. Case data about 90 cases registered during October 2012 to November 2013 was retrieved from Municipal Hospital. Controls were matched (1,1 ratio) on the date of registration with cases from same hospital. Both cases and controls were invited to participate and data was collected in a face-to-face interview. A prospective study of canine leishmaniasis (canine-CL) was also conducted at Civil Veterinary Hospital in the same area. Suspected dogs with skin ulceration signs were included in the study and blood samples were collected. Statistical analyses were conducted to determine association between various parameters and outcome of interest.

Results

The ages of cases ranged from 1 to 76 years (median = 15 years) and proved to be protective factor i.e. increase in each year in age reduced the likelihood of being infected with human-CL [Odds Ratio (OR) = 0.4, 95% Confidence Interval (CI) = 0.25–0.76]. People sleeping outsides in an open area were more likely to become a case (OR = 8.7, 95% CI = 2.90–26.37) than a control. Poor sanitary condition inside the house (OR = 3.3, 95% CI 1.03–10.56) and presence of other animals in house (livestock, poultry) (OR = 3.6, 95% CI = 1.07–12.12) also identified as risk factors of high significance. The proportion of positive dogs with canine-CL was 21.05% and was significantly associated with human-CL cases in the same area (p < 0.05).

Conclusions

We concluded that adopting self-protections measures against sand-fly, and maintaining good hygiene may lower the risk of human-CL. One-Health Strategy is suggested to control leishmaniasis in human and dog population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06327-w.

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.

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.

Burden and risk factors of cutaneous leishmaniasis in a peri-urban settlement in Kenya, 2016

Background

Cutaneous leishmaniasis is a neglected disease known to cause significant morbidity among the poor. We investigated a suspected outbreak to determine the magnitude of cases, characterize the cases and identify risk factors of cutaneous leishmaniasis in Gilgil, a peri-urban settlement in Central Kenya.

Methods

Hospital records for the period 2010–2016 were reviewed and additional cases were identified through active case search. Clinical diagnosis of cutaneous leishmaniasis was made based on presence of ulcerative, nodular or papular skin lesion. The study enrolled 58 cases matched by age and neighbourhood to 116 controls in a case control study. Data was collected using structured questionnaires and simple proportions, means and medians were computed, and logistic regression models were constructed for analysis of individual, indoor and outdoor risk factors.

Results

Of the 255 suspected cases of cutaneous leishmaniasis identified, females constituted 56% (142/255) and the median age was 7 years (IQR 7–21). Cases occurred in clusters and up to 43% of cases originated from Gitare (73/255) and Kambi-Turkana (36/255) villages. A continuous transmission pattern was depicted throughout the period under review. Individual risk factors included staying outside the residence in the evening after sunset (OR 4.1, CI 1.2–16.2) and visiting forests (OR 4.56, CI 2.04–10.22). Sharing residence with a case (OR 14.4, CI 3.8–79.3), residing in a thatched house (OR 7.9, CI 1.9–45.7) and cracked walls (OR 2.3, CI 1.0–4.9) were identified among indoor factors while sighting rock hyraxes near residence (OR 5.3, CI 2.2–12.7), residing near a forest (OR 7.8, CI 2.8–26.4) and having a close neighbour with cutaneous leishmaniasis (OR 6.8, CI 2.8–16.0) were identified among outdoor factors.

Conclusions

We identify a large burden of cutaneous leishmaniasis in Gilgil with evidence of individual, indoor and outdoor factors of disease spread. The role of environmental factors and rodents in disease transmission should be investigated further

Environmental and socioeconomic risk factors associated with visceral and cutaneous leishmaniasis: a systematic review

We performed a systematic review of the literature published since 1900 about leishmaniasis a neglected vector-borne disease, focused on environmental and social risk factors for visceral (VL) and cutaneous leishmaniasis (CL) to better understand their impact on the incidence of disease. The search terms were "leishmaniasis" AND "risk factors" using Google Scholar, PudMed, and Scielo. We reviewed 177 articles, 95 studies for VL, 75 for CL, and 7 on both forms. We identified 14 categories of risk factors which were divided into three groups: socioeconomic (7), environmental (5), and climate (2) variables. Socioeconomic factors were also associated with disease incidence in vulnerable human populations of arid and tropical developing regions. Environmental and climate factors showed significant associations with the incidence of VL and CL in all the studies that considered them. Proximity to natural vegetation remnants increased disease risk in both the New and Old World while the climate conditions favorable for disease transmission differed among regions. We propose a common conceptual framework for both clinical forms that highlights networks of interaction among risk factors. In both clinical forms, the interplay of these factors played a major role in disease incidence. Although there are similarities in environmental and socioeconomic conditions that mediate the transmission cycle of tropical, arid, and Mediterranean regions, the behavior of vector and reservoirs in each region is different. Special attention should be given to the possibility of vector adaptation to urban environments in developing countries where populations with low socioeconomic status are particularly vulnerable to the disease.

ISC1, a new Leishmania donovani population emerging in the Indian sub-continent: Vector competence of Phlebotomus argentipes

Visceral leishmaniasis (VL), the most severe form of the disease, is caused by Leishmania donovani in the Indian sub-continent (ISC). Whole genome sequencing studies revealed that two parasite populations exist in the ISC: a main population named the Core Group (CG) found mostly in the lowlands, and a new, genetically different subpopulation called ISC1. Parasites belonging to the CG were shown to be responsible for the recent epidemics, while the ISC1 variant was originally identified in hilly districts of Nepal and was later on increasingly found in the lowlands. Importantly, the ISC1 and CG isolates differ in their drug susceptibility and virulence signatures, suggesting that ISC1 constitutes an emerging and functionally different variant of L. donovani. In present study we aimed to address the potential of ISC1 transmission by the natural vector of L. donovani in the lowlands, Phlebotomus argentipes. By experimental infection of sand flies with parasites of the different genotypes, we demonstrate that ISC1 and CG strains are developing similarly in P. argentipes, suggesting that P. argentipes is a fully competent vector for ISC1 parasites. Integration of previous and current findings shows thus that ISC1 is a new and different variant of L. donovani, fully adapted to spread in the ISC through the main vector. This information is directly useful for managers of the elimination program. Furthermore, integration of our successive studies (genotyping, phenotyping and vector competence) demonstrates the relevance of molecular surveillance and should be of interest for scientists working on vector borne diseases and control managers.

Cutaneous leishmaniasis a neglected tropical disease: community knowledge, attitude and practices in an endemic area, Northwest Ethiopia

Background

Cutaneous leishmaniasis is one of the neglected tropical diseases in the Ethiopian highlands and studies on assessment of knowledge, attitude and practice of the community in endemic areas are scanty. The study aimed to assess the knowledge, attitude towards cutaneous leishmaniasis and treatment seeking practices in people living in the endemic highlands areas in the Northwest, Ethiopia and to provide evidence-based information to guide development of appropriate interventions to reduce the impact of cutaneous leishmaniasis on communities.

Methods

Quantitative cross-sectional study was conducted in cutaneous leishmaniasis endemic districts (woredas) using a semi structured questionnaire. Households were randomly selected according to probability proportional to size of households in each enumeration area. Systematic random sampling of eligible households was based on the number of households recorded during listing of households. Descriptive statistics was used to describe numerical data, organise and summarise the data in a manner that gave meaning to the numerical form. Frequency tables were used to show descriptive analysis and regression analysis was used to determine correlation between variables.

Results

Majority of respondents 321(78.7%) lived in rural areas, age ranged between 18 and 85 years and most were farmers. Illiteracy was high (47.6%) among respondents and majority 358(87.8%) had seen patients with CL. Less than quarter (21.6%) had heard about sand flies and knowledge on the peak transmission period was low (46.3%). About 192 (47.1%) of the respondents indicated disfiguring lesions were the major clinical presentations, less than half 55(27.5%) of urban residents believed CL was treatable compared to 145(72.5%) of rural residents (P < 0.001). Traditional medicines were indicated as best treatment option by 209(51.2%) compared to 114(27.9%) for modern treatment. Major factors influencing treatment options included accessibility to treatment facilities, distance and short duration of treatment. Participants expressed negative experiential attitude and perceived control towards modern treatment because of inaccessibility and distance from where modern treatment is provided.

Conclusion

Priority should be given to primary prevention and appropriate awareness campaigns on lesion recognition. Information on modern treatment should be intensified.

Leishmaniasis in Northern Morocco: Predominance of Leishmania infantum Compared to Leishmania tropica

In Morocco, Leishmania infantum species is the main causative agents of visceral leishmaniasis (VL). However, cutaneous leishmaniasis (CL) due to L. infantum has been reported sporadically. Moreover, the recent geographical expansion of L. infantum in the Mediterranean subregion leads us to suggest whether the nonsporadic cases of CL due to this species are present. In this context, this review is written to establish a retrospective study of cutaneous and visceral leishmaniasis in northern Morocco between 1997 and 2018 and also to conduct a molecular study to identify the circulating species responsible for the recent cases of leishmaniases in this region. Data concerning leishmaniases cases were collected from the Epidemiology and Disease Control Directorate from 1997 to 2018. Human samples obtained from peripheral laboratories were examined using PCR-ITS1 method. The ITS1 products were subjected to digestion with the restriction endonuclease Mn1-I. Between 1997 and 2018, a total of 1,255 cases of cutaneous and visceral leishmaniasis were recorded in Tangier-Tetouan-Al Hoceima Region, i.e., 1.56% of the reported cases in Morocco (1,255/80,299). Concerning the geographical study covering the period 2007-2018, 79.5% (105/132) of the sectors were affected by leishmaniases. The molecular results showed that Humans were found to be infected with the L. infantum species with a high infection rate compared to L. tropica infection. Moreover, molecular characterization using ITS1 PCR-RFLP showed that the density of L. infantum was significantly higher (n = 68/81; 84%) than that of L. tropica (n = 13/81; 16%) (P-value 9.894e-10). While regarding visceral leishmaniasis, L. infantum was the only species responsible of this form. These findings of this study showed the emergence of L. infantum in Morocco and suggest that this species might be more prevalent than previously thought. Furthermore, the molecular determination of L. infantum will be helpful for control strategies by taking into consideration the reservoir of this species.

Leishmaniasis recidivans by Leishmania tropica in Central Rift Valley Region in Kenya

OBJECTIVES

This study sought to determine the endemic Leishmania species, the clinical features of cutaneous leishmaniasis (CL) in the Central Rift Valley in Kenya and to give an account on unresponsiveness to treatment in the region.

METHODS

Participants were clinically identified and grouped into untreated, classical and recidivate based on clinical manifestation and clinical data. Leishmaniasis recidivans lesions were scaly hyperemic papules that appeared before the classic lesion had healed or after healing. The demographics and socio-economic data were recorded and lesion scraping samples screened through microscopy and Internal Transcribed Spacer 1-PCR. Leishmania species were identified using Restriction Fragment Length Polymorphism.

RESULTS

A total of 52 participants were sampled, of which, 44.2% of the cases were recidivate and L. tropica the only species identified. All patients had been treated using sodium stibogluconate (SSG) which is the recommended first-line drug in Kenya. 60% of the patients experienced prolonged exposure to the drug (>30 days).

CONCLUSION

L. tropica is the endemic Leishmania species for CL leading to classical and leishmaniasis recidivans. Treatment of CL in the area is not effective hence, alternative measures/therapy should be considered to cope with the unresponsiveness.

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

Background

Cutaneous leishmaniasis (CL) is an endemic disease in Bolivia, particularly in the rainforest of Cochabamba, in the municipality of Villa Tunari. The precarious, dispersed, and poorly accessible settlements in these farming communities make it difficult to study them, and there are no epidemiological studies in the area. The aim of the present study was to identify the risk factors associated with cutaneous leishmaniasis.

Methods

A cross-sectional study was conducted in August 2015 and August 2016 in two communities of Villa Tunari, Cochabamba. The cases were diagnosed through clinical examinations, identification of the parasite by microscopic examination, and the Montenegro skin test. Risk factors were identified through logistic regression.

Results

A total of 274 participants (40.9% female and 59.1% male) were surveyed, of which 43% were CL positive. Sex was the only factor associated with CL with three times more risk for men than for women; this finding suggests a sylvatic mechanism of transmission in the area.

Conclusions

It is advisable to focus on education and prevention policies at an early age for activities related to either leisure or work. Further research is needed to assess the influence of gender-associated behavior for the risk of cutaneous leishmaniasis.

Effects of environmental factors and storage conditions on the performance of Olyset® Plus against sand flies in WHO cone bioassays

BACKGROUND

Leishmaniasis, visceral and cutaneous, is seen in Turkey and has both public and veterinary importance. So far, four Leishmania species and their vectors have been detected in Turkey. Vector control is essential in endemic areas and several personal protection methods are available including long-lasting insecticidal nets (LLINs). In this study, we aimed to measure the effects of usage and storage conditions on LLINs in a village-scale study.

METHODS

Olyset(®) Plus bed nets were set up in different climatic conditions (rain, exposed to sunlight and humidity) and collected after 6 months. The effectiveness of bed nets were tested by WHO's cone test method using wild-caught sand flies.

RESULTS

Bed nets, which were placed directly exposed to sunlight (A1, A2) showed lower (17.2%) knock down effect compared to bed nets placed indoors (A3, B1). Twenty-four hour mortality was 100% for the five study groups (A2, A3, B1, C1, C2) whereas group A1 was found to have a lower mortality rate (44.4%).

CONCLUSION

Bed nets need to avoid direct exposure to sunlight. When used and stored in appropriate conditions (cool, well-ventilated place away from sunlight) they can be used as an effective vector control tool in endemic areas.

Worldwide risk factors in leishmaniasis

Recently, vector-borne parasitic diseases such as leishmaniasis have been emerged or re-emerged in many geographical areas and resulted in global health and economic concerns that involve humans, domestic animals and wild life. The ecology and epidemiology of leishmaniasis are affected by the between host, reservoir and vector (human, animal and sandfly) and the environment. Important drivers for the emergence and spread of leishmaniasis include environmental factors such as alterations in temperature and water storage, irrigation habits, deforestation, climate changes, immunosuppression by HIV or organ transplant, development of drug resistance, increase traveling to endemic regions and dog importation. War, poor socio-economic status and low level household are also major contributors to the spread of this disease. Health education via the public media and training should be implemented by international organizations and governmental agencies in collaboration with research institutions. Fully protection during transmission season, using bednets and insecticides and reservoirs' control should be also mentioned in the planning. Based on the findings of the recent studies and high prevalence of leishmaniasis, it is concluded that serious public health monitoring should be considered.

Old World Leishmaniasis: an ancient disease with nonstandardized microscopic and clinical classifications

BACKGROUND

Microscopic and clinical classifications of cutaneous leishmania have been set in the 1980s. Since then, they have been used invariably. Lebanon, a nonendemic country, is suffering from a leishmaniasis epidemic because of the massive population influx from endemic Syria.

DESIGN

Patients diagnosed and speciated with leishmania (n = 169) using molecular and microscopic analysis were studied. General demographic data, microscopic data [Ridley's pattern (RP), microscopic pattern, Parasitic Index (PI)] and clinical stage were documented. Clinical score was scored as: 1: inflammatory; 2: proliferative/reorganization; 3: healed phases. The three patterns were studied in comparison to the lesion age and PI.

RESULTS

At low PI, the clinical score and microscopic pattern showed healing scores (scores 3 and 4, respectively). In contrast, RP showed variable distribution at low PI. The same pattern is noted when correlating the different patterns with high PI. In comparison to lesion age, none of the three patterns showed the predicted linear correlation with lesion progression.

CONCLUSION

In the studied population, the previously adopted classifications did not correlate with the disease progression. Such findings may raise the possibility of evolving disease. The proposed clinical and microscopic patterns showed better correlation with the disease progression.

Natural hybrid of Leishmania infantum/L. donovani: development in Phlebotomus tobbi, P. perniciosus and Lutzomyia longipalpis and comparison with non-hybrid strains differing in tissue tropism

Background

Infection caused by parasites from L. donovani complex can manifest as a serious visceral disease or a self-healing milder cutaneous form. The different tropism and pathology in humans is caused by the interaction between parasites, host and vector determinants but the mechanisms are not well understood. In Cukurova region in Turkey we previously identified a major focus of cutaneous leishmaniasis caused by L. donovani/infantum hybrids (CUK strain) and isolated this parasite from the locally abundant sand fly, Phlebotomus tobbi. Here, we present the first experimental study with P. tobbi. We tested the susceptibility of this species to various Leishmania under laboratory conditions, characterized glycoproteins in the P. tobbi midgut putatively involved in parasite-vector interaction and compared the development of the CUK strain in the sand fly with one other dermotropic and three viscerotropic strains belonging to the L. donovani complex.

Methods

Females of laboratory reared P. tobbi, P. perniciosus and Lutzomyia longipalpis were infected using membrane feeding on rabbit blood containing promastigotes of various Leishmania species with different tropisms. The individual guts were checked microscopically for presence and localization of Leishmania parasites; the number of parasites was assessed more precisely by qPCR. In addition, glycosylation of midgut proteins of P. tobbi was studied by lectin blotting of midgut lysate with lectins specific for terminal sugars of N-type and O-type glycans.

Results

High infection rates, heavy parasite loads and late-stage infection with colonization of the stomodeal valve were observed in P. tobbi infected by Leishmania major or L. infantum CUK hybrid. In parallel, lectin blotting revealed the presence of O-glycosylated proteins in the P. tobbi midgut. In P. perniciosus and L. longipalpis all five Leishmania strains tested developed well. In both vectors, significantly higher parasite numbers were detected by qPCR for dermotropic L. donovani from Cyprus, however, in all other parameters studied, including localization of infection and colonization of stomodeal valve, dermotropic and viscerotropic strains were not significantly different.

Conclusions

We showed high susceptibility of P. tobbi to various Leishmania spp. This, together with the presence of O-glycosylated midgut proteins in their midguts demonstrate that P. tobbi is a permissive vector. Two dermotropic and three viscerotropic strains from the L. donovani complex developed late-stage infections in natural L. infantum vectors, P. perniciosus and L. longipalpis and none of the parameters studied seem to be linked with different tropism of parasites in the vertebrate host.

Evaluation of conjunctival swab sampling in the diagnosis of canine leishmaniasis: A two-year follow-up study in Çukurova Plain, Turkey

The diagnosis of canine leishmaniasis (CanL) in symptomatic and asymptomatic dogs is a very important and problematic public health issue in Turkey. A longitudinal study was carried out on dogs in selected villages in the Çukurova Plain in Turkey, from July 2011 to June 2013, where cutaneous (CL) and visceral (VL) leishmaniasis is endemic. The study aimed to determine the prevalence of CanL and to evaluate the early diagnostic performance of the non-invasive conjunctival swab nested PCR (CS n-PCR) test in comparison with the Indirect Fluorescent Antibody Test (IFAT). The consecutive blood and CS samples from a representative number of dogs (80-100 dogs/each survey) were collected in a cohort of 6 villages located in the area. Clinical symptoms, demographic and physical features about each dog were noted and lymph node aspiration samples were obtained from selected dogs with lymphadenopathy. In four surveys during the period, a total of 338 sets (blood and CS) of samples from 206 dogs were obtained, such that 83 dogs were sampled more than once. In the cross-sectional analysis, the CanL prevalence was found to be 27.18% (between 7.14% and 39.13%) by IFAT and 41.74% (between 29.03% and 46.66%) by CS n-PCR. The isolated strains were identified as Leishmania infantum MON-1 (n=9) and MON-98 (n=2) by MLEE analysis. Genetic studies targeting the Hsp70 and ITS1 regions performed on 11 dog isolates also showed two clear separate groups. According to IFAT results, 24 of the 83 dogs sampled more than once showed seroconversion (n=19) or a four-fold increase in Ab titers (n=5), while 17 were positive in the initial screening. Forty-two dogs stayed negative during the whole period. The natural Leishmania exposure rate was detected as 31.14% in the study area. CS n-PCR only detected Leishmania infection earlier than IFAT in 8 dogs. No statistical difference was found after the analysis of demographical and physical data. The results indicated that (i) circulation of the dog population is very common in settlements in the Çukurova Plain, but the disease prevalence is high and stable, (ii) the performance of CS n-PCR for detecting Leishmania-dog contact is higher than IFAT, (iii) and some of the parasites isolated from dogs have different zymodemes and/or genotypes from previous human and sand fly isolates; suggesting the probability of two different cycles of leishmaniasis in this particular area. This hypothesis should be supported by future studies targeting vectors and reservoirs.

Cutaneous leishmaniasis: recent developments in diagnosis and management

This review focuses on recent developments in the diagnosis, treatment, management, and strategies for the prevention and control of cutaneous leishmaniasis (CL) caused by both Old and New World Leishmania species. CL is caused by the vector-borne protozoan parasite Leishmania and is transmitted via infected female sandflies. The disease is endemic in more than 98 countries and an estimated 350 million people are at risk. The overall prevalence is 12 million cases and the annual incidence is 2–2.5 million. The World Health Organization considers CL a severely neglected disease and a category 1 emerging and uncontrolled disease. The management of CL differs from region to region and is primarily based on local experience-based evidence. Most CL patients can be treated with topical treatments, but some Leishmania species can cause mucocutaneous involvement requiring a systemic therapeutic approach. Moreover, Leishmania species can vary in their sensitivity to available therapeutic options. This makes species determination critical for the choice of treatment and the clinical outcome of CL. Identification of the infecting parasite used to be laborious, but now the Leishmania species can be identified relatively easy with new DNA techniques that enable a more rational therapy choice. Current treatment guidelines for CL are based on poorly designed and reported trials. There is a lack of evidence for potentially beneficial treatments, a desperate need for large well-conducted studies, and standardization of future trials. Moreover, intensified research programs to improve vector control, diagnostics, and the therapeutic arsenal to contain further incidence and morbidity are needed.

Evaluation of the efficacy of Olyset® Plus in a village-based cohort study in the Cukurova Plain, Turkey, in an area of hyperendemic cutaneous leishmaniasis

The aim of this study was to measure the protective efficacy of Olyset(®) Plus, a new long-lasting factory-treated insecticidal net (LLIN) incorporated with 2% permethrin and 1% of the synergist piperonyl butoxide (PBO), against cutaneous leishmaniasis (CL) transmission under field conditions. A village-scale trial, promoting the use of LLIN by the local inhabitants of the study area was conducted as a pilot study in a new hyperendemic focus of CL caused by a Leishmania infantum/L. donovani hybrid parasite transmitted by proven vector species Phlebotomus tobbi in Cukurova Plain, Adana, Turkey, between May, 2013 and May, 2014. The study area comprised eight villages; two of them were selected as an intervention village with Olyset(®) Plus net (Kizillar) and a control village without net application (Malihidirli). Six villages with surrounding allopatric barriers were utilized as a buffer zone cluster between intervention and control villages. Monthly entomological surveys were performed in the intervention and control villages and Damyeri, representing the other six villages, to collect adults of Phlebotomus tobbi. Results showed a significant reduction in cutaneous leishmaniasis incidence in the intervention village from 4.78% to 0.37%. The protective efficacy rate of LLIN was 92.2%. In contrast, incidence rates increased in the control village from 3.67% to 4.69%. We also evaluated residual insecticide levels of used nets after six and 12 months of usage. It was determined that the nets had retained full insecticidal strength. These results highlight the value of real-world data on bed net effectiveness and longevity to guide decisions regarding sand fly control strategies. To the best of our knowledge, this is the first field study to evaluate Olyset(®) Plus efficacy in a hyperendemic cutaneous leishmaniasis area.

Cutaneous leishmaniasis: knowledge, attitude and practices of the inhabitants of the Kani forest tribal settlements of Tiruvananthapuram district, Kerala, India

Cutaneous leishmaniasis (CL) is reported among Kani tribes in forest settlements of Tiruvananthapuram district, Kerala, India. Epidemiological investigations are ongoing and 27 histopathologically confirmed cases of CL have been reported from five settlements indicating transmission of disease within settlements. One of the priorities for control/prevention of CL is to create awareness among the community and ensure optimal utilization of interventions. First step in this direction would be to carry out a situation analysis on prevailing knowledge, attitude and practice (KAP) of inhabitants. A study among 103 respondents from 10 Kani tribal settlements showed that though 39.8% of respondents recognized pictures of CL shown to them, but did not have any lay perceptions. There was absolutely no awareness on vector, transmission, risk factors and control measures. The role of sandflies in CL causation was not known to the residents and this prevented them from using any personal protection and adhering to control measures which in turn pose risk of spread of infection within settlements and to newer areas. CL has emerged as a challenging infection in this area and an urgent need for designing appropriate preventive measures and health education strategies is addressed in this article.

The emergence of Leishmania major and Leishmania donovani in southern Turkey

BACKGROUND

In southern Turkey, Leishmania tropica and L. infantum are both the causative agents of cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL), respectively. However, L. major and L. donovani were known to exist after the influx of Syrian refugees.

METHODS

Between the years of July 2003 and July 2013, a total of 167 smears and 113 bone marrow samples were taken from CL and VL-suspected cases, respectively. Samples were analysed through real-time PCR and ITS1 DNA sequencing.

RESULTS

One hundred and seven 64% (107/167) smears and 56% (63/113) bone marrow samples were positive for leishmaniasis according to the real-time PCR. Three different Leishmania species were found in the 107 CL cases by real-time PCR: 42% (45/107) L. tropica, 36.5% (39/107) L. infantum and 21.5% (23/107) L. major. In addition, three different Leishmania species were identified in the 63 VL cases: 60.3% (38/63) L. infantum, 30.2% (19/63) L. donovani and 9.5% (6/63) L. tropica using real-time PCR. The results of real-time PCR were confirmed with Leishmania ITS1 DNA sequencing.

CONCLUSIONS

This study revealed that in southern Turkey, L. major and L. donovani were the aetiological agents of CL and VL, respectively. It was assumed that emergence of L. major and L. donovani was due to influx of Syrian refugees, as well as the effects of global warming.

Genomic confirmation of hybridisation and recent inbreeding in a vector-isolated Leishmania population

Although asexual reproduction via clonal propagation has been proposed as the principal reproductive mechanism across parasitic protozoa of the Leishmania genus, sexual recombination has long been suspected, based on hybrid marker profiles detected in field isolates from different geographical locations. The recent experimental demonstration of a sexual cycle in Leishmania within sand flies has confirmed the occurrence of hybridisation, but knowledge of the parasite life cycle in the wild still remains limited. Here, we use whole genome sequencing to investigate the frequency of sexual reproduction in Leishmania, by sequencing the genomes of 11 Leishmania infantum isolates from sand flies and 1 patient isolate in a focus of cutaneous leishmaniasis in the Çukurova province of southeast Turkey. This is the first genome-wide examination of a vector-isolated population of Leishmania parasites. A genome-wide pattern of patchy heterozygosity and SNP density was observed both within individual strains and across the whole group. Comparisons with other Leishmania donovani complex genome sequences suggest that these isolates are derived from a single cross of two diverse strains with subsequent recombination within the population. This interpretation is supported by a statistical model of the genomic variability for each strain compared to the L. infantum reference genome strain as well as genome-wide scans for recombination within the population. Further analysis of these heterozygous blocks indicates that the two parents were phylogenetically distinct. Patterns of linkage disequilibrium indicate that this population reproduced primarily clonally following the original hybridisation event, but that some recombination also occurred. This observation allowed us to estimate the relative rates of sexual and asexual reproduction within this population, to our knowledge the first quantitative estimate of these events during the Leishmania life cycle.

Sexual reproduction is predicted to be a rare event in Leishmania parasites, as evidenced by detection of rare parasite hybrids in natural populations using molecular methods. Recently, a sexual cycle has been detected experimentally in parasites within the sand fly vector (that transmits this pathogenic microorganism to mammalian species including man, causing human leishmaniasis). In this study, we have used whole genome sequencing to investigate genetic variation at the highest level of resolution in Leishmania parasites isolated from sand flies in a defined focus of leishmaniasis in southeast Turkey. Using a range of analytical tools, we show that variation in these parasites arose following a single cross between two diverse strains and subsequent recombination between the progeny, despite mainly clonal reproduction in the parasite population. We have thus been able to derive quantitative estimates of the relative rates of sexual and asexual reproduction during the Leishmania life cycle for the first time, information that will be critical to our understanding of the epidemiology and evolution of this genus.

A newly emerged cutaneous leishmaniasis focus in central Iran

OBJECTIVES

This study was performed to evaluate the epidemiological status of cutaneous leishmaniasis (CL) in the most important endemic foci of Qom Province, central Iran. The city of Qom is the largest center for Shi'a scholarship in the world and is a significant pilgrimage destination.

METHODS

During 2006-2011, all suspected CL patients with skin lesion(s) referred to regional health centers of Ghomrood and Ghanavat regions, and all actively detected cases, were examined clinically and parasitologically for CL. Patient information was recorded and patients were categorized based on the number and size of the lesions. Odds ratios (OR) of different risk factors were calculated.

RESULTS

A total of 849 (59.2% male, 40.8% female) confirmed cases of CL were enrolled; the average incidence rate of the disease was 14.9 per 100000 people. During the study period 2006-2011, the trend in CL incidence showed no sudden variations in the areas studied, except for an outbreak of CL in 2009. Leishmania major was identified as the causative agent based on internal transcribed spacer 1 (ITS1) ribosomal DNA PCR analysis. During the study period, the age distribution of CL cases was relatively stable, with the majority (50%) of patients aged 1-25 years. Most cases (n=468; 55.1%) had a single lesion and 82 (9.6%) patients had four or more lesions (range 1-29). The risk of developing multiple lesions was significantly increased in patients with seasonal jobs (summer workers) (p=0.023; OR 1.516) and significantly decreased in patients who were affected in winter (p=0.010; OR 0.398). The risk of developing large-sized lesions (>1cm) was significantly increased in patients in the age groups>25 years (p=0.001-0.015; OR 2.5-3.5) and decreased in patients with seasonal jobs (summer workers) (p=0.005; OR 0.570).

CONCLUSIONS

The present data show the importance of CL as a health problem in suburban areas of Qom Province. In order to identify other epidemiological aspects of leishmaniasis in this area, studies on vectors and reservoirs are recommended. Since leishmaniasis caused by L. major is typically zoonotic, control measures should focus on rodents as the main reservoirs and Phlebotomus papatasi as the main vector. Awareness should be raised in the high-risk populations comprising people with diabetes, young adults (<25 years old), and those who work outdoors during the summer.

Transmission and epidemiology of zoonotic protozoal diseases of companion animals

Over 77 million dogs and 93 million cats share our households in the United States. Multiple studies have demonstrated the importance of pets in their owners' physical and mental health. Given the large number of companion animals in the United States and the proximity and bond of these animals with their owners, understanding and preventing the diseases that these companions bring with them are of paramount importance. Zoonotic protozoal parasites, including toxoplasmosis, Chagas' disease, babesiosis, giardiasis, and leishmaniasis, can cause insidious infections, with asymptomatic animals being capable of transmitting disease. Giardia and Toxoplasma gondii, endemic to the United States, have high prevalences in companion animals. Leishmania and Trypanosoma cruzi are found regionally within the United States. These diseases have lower prevalences but are significant sources of human disease globally and are expanding their companion animal distribution. Thankfully, healthy individuals in the United States are protected by intact immune systems and bolstered by good nutrition, sanitation, and hygiene. Immunocompromised individuals, including the growing number of obese and/or diabetic people, are at a much higher risk of developing zoonoses. Awareness of these often neglected diseases in all health communities is important for protecting pets and owners. To provide this awareness, this review is focused on zoonotic protozoal mechanisms of virulence, epidemiology, and the transmission of pathogens of consequence to pet owners in the United States.