Dataset Information

First Evidence from Sri Lanka for Subphenotypic Diversity within L. donovani-Induced Classical Cutaneous Leishmaniasis.

ABSTRACT: Sri Lanka reports a large focus of Leishmania donovani-induced cutaneous leishmaniasis (CL) with CL as the main clinical entity. Two independent, long existed, and clinicoepidemiologically different transmission foci in the northern region (NR) and southern region (SR) were recently reported. Current project is an extension to this previous study. Clinical diversity within a profile of classical cutaneous leishmaniasis (CCL) in a focus of L. donovani-induced CL is described for the first time. Patients with laboratory confirmed CCL (n = 550) from NF and SF were evaluated. Lesions in both foci were found to have all classical developmental stages (small and large nodules, ulcerating nodules, and ulcers) and other identified changes (multiplication, ulceration, and enlargement). Main difference was in the proportions of lesions progressing in to each different stages, proportions of lesion undergoing the main changes, and in timing of these changes during the course of a lesion. Northern focus reported a smaller proportion of lesions showing enlargement and ulceration, and a longer period of time was also required for these changes when compared to same in southern focus. In northern focus, most lesions remained small and nonulcerating and showed a higher tendency to multiply while most lesions reported in southern focus enlarged and ulcerated rapidly and remained single. Current study also evidenced a wider spectrum in the rate and pattern of progression of a skin lesion and high individual variation which could mask these region-based differences. Parasitic, vector-related, or a host etiology is suggested. Slow progressing nonulcerating infections in North may be the result of a well-adopted parasite strain that coevolved with its host for a long period while inducing only a minimal host response. This could be one among many reasons for previously observed silent expansion in northern focus while southern focus remained more confined and stable over time. Small nonprogressive, nondisturbing lesions can play a major role as silent parasite reservoirs in a community. In addition, the laboratory detection rate declined significantly when lesions multiplied and enlarged indicating the need for early laboratory confirmation. Usefulness of identified features in clinical screening and management needs to be considered.

SUBMITTER: Siriwardana Y

PROVIDER: S-EPMC7861938 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature

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First Evidence from Sri Lanka for Subphenotypic Diversity within L. donovani-Induced Classical Cutaneous Leishmaniasis.

Siriwardana Yamuna Y Deepachandi Bhagya B Weerasinghe Sudath S Karunaweera Nadira N Udagedara Chandanie C Warnasuriya Wipula W Ranawaka Ranthilaka R RR Kahawita Indira I

BioMed research international 20210127

Sri Lanka reports a large focus of Leishmania donovani-induced cutaneous leishmaniasis (CL) with CL as the main clinical entity. Two independent, long existed, and clinicoepidemiologically different transmission foci in the northern region (NR) and southern region (SR) were recently reported. Current project is an extension to this previous study. Clinical diversity within a profile of classical cutaneous leishmaniasis (CCL) in a focus of L. donovani-induced CL is described for the ...[more]

PMID: 33575327

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Project description:Sri Lanka is a recent focus having Leishmania donovani induced cutaneous leishmaniasis (CL) as the main clinical entity. A separate clinical entity within profile of CL was described in this study. Laboratory confirmed cases of CL (n= 950, 2002-2014) were analysed. Most lesions showed known classical developmental stages of CL (CCL) observed in other CL endemic settings while few cases (13%, 122/950) showed atypical skin manifestations (ACL). Clinical, geographical, and treatment response patterns of ACL were different from those of CCL. ACL was mainly found among males (68.0%), in 21-40 year age group (51.6%), and reported delayed treatment seeking (23.5% vs 16.3% in CCL), more nonclassical onset (lesions other than acne form <1cm sized papules), (12.1 vs 2.7%, P<0.05.), more head and neck lesions (41.5%. vs 27.2%), more large lesions (>4cm), (18.6 vs 9.9%), and poor laboratory positivity rates (65.6% vs 88.2%) when compared to CCL. When compared to lesions reporting a typical onset, lesions reporting nonclassical onset were more likely to develop ACL later on (50.1% vs 10.7%). As compared to lesions on limbs, those on head and neck and trunk were more likely to be ACL (7.0%, 16.3%, and 22.8%, respectively, P<0.05). ACL features were not age or gender dependent. Highest proportion within ACL category (32.8%) and small proportion of CCL (10.1%) originated from less leishmaniasis prevalent areas (other regions) (P<0.05). North reported more ACL than South (15.9% vs 7.4%). A total of 95 CL cases with a significant travel history were further analyzed. Residents of other regions when acquired infection from North or South developed more ACL than residents in North or South (60.9% vs 15.9% and 42.9% vs 7.4% respectively). Patients in other regions when travelled to North developed more ACL than when they travelled to South (60.9%, 42.9%). ACL and CCL required an average of 18 doses over 16.7 months and 10 doses over 12 weeks, respectively, to achieve a complete clinical cure. Underlying host immunological factors, parasite strain variations and regional variations of both could be underlying etiologies. Established independent transmission within less leishmaniasis prevalent regions combined with an unusual clinical picture leading to poor clinical suspicion and low laboratory confirmation rate will pose potential difficulties in early case detection in these highly populated and commercialized areas. This in turn will further facilitate silent and high disease transmission.

Project description:Among the most central questions in Leishmania research is why some species remain in the skin dermis at the site of infection by the sand fly vector whereas other species migrate to visceral organs where they cause fatal visceral leishmaniasis. Although L. donovani is the species typically responsible for visceral leishmaniasis, an atypical L. donovani strain is the etiologic agent for cutaneous leishmaniasis in Sri Lanka. To identify molecular determinants for visceral disease, we have analysed the phenotype and genotype of two L. donovani clinical isolates from Sri Lanka where one isolate was derived from a cutaneous leishmaniasis patient (CL) and the other from a visceral leishmaniasis patient (VL). These isolates cause dramatically different pathology when introduced into mice; notably the CL isolate has lost the ability to survive in visceral organs while the VL isolate was highly virulent in visceral organs of BALB/c mice. Whole genome sequencing of the CL and VL isolates revealed that these genomes were very similar as there were no gene deletions and few individual gene amplifications. Indels resulting in frame shifts and loss/gain of stop codons resulted in 13 distinct pseudogenes present in each of the CL and VL isolates. There were 154 non-synonymous SNPs specific to the CL isolate and 193 non-synonymous SNPs specific to the VL isolate. Genome wide gene expression analysis revealed several transcript level differences, including the A2 virulence gene resulting in higher expression of A2 proteins in the VL isolate than in the CL isolate. Genotypic variations relevant to pathology and tropism in Leishmania can be interrogated by reverse genetics. Experimentally increasing A2 expression in the CL isolate through gene transfer significantly increased itM-bM-^@M-^Ys ability to survive in the spleen of BALB/c mice and conversely, down-regulating A2 expression in the VL isolate abrogated attenuated its survival in BALB/c mice. These observations reveal that there are relatively few genetic differences between the CL and VL isolates apart from the A2 genes, but collectively these have profound effects on human disease and experimentally infected mice. 6 Samples in total, 3 each from VL and CL causing isolates were analyzed by Splice Leader RNASeq. These three samples from each of the isolates were grown to form one of the following three lifestages, Promastigotes, Macrophage derived Amastigotes, Axenic Amastigotes.

Project description:Among the most central questions in Leishmania research is why some species remain in the skin dermis at the site of infection by the sand fly vector whereas other species migrate to visceral organs where they cause fatal visceral leishmaniasis. Although L. donovani is the species typically responsible for visceral leishmaniasis, an atypical L. donovani strain is the etiologic agent for cutaneous leishmaniasis in Sri Lanka. To identify molecular determinants for visceral disease, we have analysed the phenotype and genotype of two L. donovani clinical isolates from Sri Lanka where one isolate was derived from a cutaneous leishmaniasis patient (CL) and the other from a visceral leishmaniasis patient (VL). These isolates cause dramatically different pathology when introduced into mice; notably the CL isolate has lost the ability to survive in visceral organs while the VL isolate was highly virulent in visceral organs of BALB/c mice. Whole genome sequencing of the CL and VL isolates revealed that these genomes were very similar as there were no gene deletions and few individual gene amplifications. Indels resulting in frame shifts and loss/gain of stop codons resulted in 13 distinct pseudogenes present in each of the CL and VL isolates. There were 154 non-synonymous SNPs specific to the CL isolate and 193 non-synonymous SNPs specific to the VL isolate. Genome wide gene expression analysis revealed several transcript level differences, including the A2 virulence gene resulting in higher expression of A2 proteins in the VL isolate than in the CL isolate. Genotypic variations relevant to pathology and tropism in Leishmania can be interrogated by reverse genetics. Experimentally increasing A2 expression in the CL isolate through gene transfer significantly increased it’s ability to survive in the spleen of BALB/c mice and conversely, down-regulating A2 expression in the VL isolate abrogated attenuated its survival in BALB/c mice. These observations reveal that there are relatively few genetic differences between the CL and VL isolates apart from the A2 genes, but collectively these have profound effects on human disease and experimentally infected mice.

Project description:BackgroundLeishmaniasis is a neglected tropical vector-borne disease, which is on the rise in Sri Lanka. Spatiotemporal and risk factor analyses are useful for understanding transmission dynamics, spatial clustering and predicting future disease distribution and trends to facilitate effective infection control.MethodsThe nationwide clinically confirmed cutaneous leishmaniasis and climatic data were collected from 2001 to 2019. Hierarchical clustering and spatiotemporal cross-correlation analysis were used to measure the region-wide and local (between neighboring districts) synchrony of transmission. A mixed spatiotemporal regression-autoregression model was built to study the effects of climatic, neighboring-district dispersal, and infection carryover variables on leishmaniasis dynamics and spatial distribution. Same model without climatic variables was used to predict the future distribution and trends of leishmaniasis cases in Sri Lanka.ResultsA total of 19,361 clinically confirmed leishmaniasis cases have been reported in Sri Lanka from 2001-2019. There were three phases identified: low-transmission phase (2001-2010), parasite population buildup phase (2011-2017), and outbreak phase (2018-2019). Spatially, the districts were divided into three groups based on similarity in temporal dynamics. The global mean correlation among district incidence dynamics was 0.30 (95% CI 0.25-0.35), and the localized mean correlation between neighboring districts was 0.58 (95% CI 0.42-0.73). Risk analysis for the seven districts with the highest incidence rates indicated that precipitation, neighboring-district effect, and infection carryover effect exhibited significant correlation with district-level incidence dynamics. Model-predicted incidence dynamics and case distribution matched well with observed results, except for the outbreak in 2018. The model-predicted 2020 case number is about 5,400 cases, with intensified transmission and expansion of high-transmission area. The predicted case number will be 9115 in 2022 and 19212 in 2025.ConclusionsThe drastic upsurge in leishmaniasis cases in Sri Lanka in the last few year was unprecedented and it was strongly linked to precipitation, high burden of localized infections and inter-district dispersal. Targeted interventions are urgently needed to arrest an uncontrollable disease spread.

Dataset Information

First Evidence from Sri Lanka for Subphenotypic Diversity within L. donovani-Induced Classical Cutaneous Leishmaniasis.

Publications

First Evidence from Sri Lanka for Subphenotypic Diversity within <i>L. donovani</i>-Induced Classical Cutaneous Leishmaniasis.

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