Cutaneous Leishmaniasis (CL) is considered a neglected tropical disease which in Pakistan can now be considered as a growing public health problem. The exact figures on the magnitude of the disease are lacking both at the national and regional level and only a few health centres are available for diagnosis of CL. The present study was designed to identify the epidemiology of CL infection from August 2018 to December 2019 and to assess clinical aspects of CL in Baluchistan Province of Pakistan. A total of 4072 clinically suspected CL cases were analysed statistically. The highest number of CL cases were reported in May, followed by April, January and then July, February and June and the lowest number of cases were observed in March and November. The highest prevalence rate was found in males where 38% of reported cases were aged 0–9 years. The majority (24.4%) of lesions were found on the hands followed by the face in which cheeks, ears and nose were the effected organs. About 50% of the participants have single lesion while 14% of the participants had two and nearly 3% of the participants have six lesions. The atypical clinical presentations were observed in Baluchistan and common unusual presentations were lupus erythematosus. The study findings suggest that more epidemiological studies and health education campaigns are needed for the population awareness regarding CL in Baluchistan. It is recommended that risk factors should be evaluated to establish control and management strategies to prevent disease at the individual and community level.

Leishmania rely heavily on glycans to complete their digenetic life cycle in both mammalian and phlebotomine sand fly hosts. Leishmania promastigotes secrete a proteophosphoglycan-rich gel (Promastigote Secretory Gel, PSG) that is regurgitated during transmission and can exacerbate infection in the skin. Here we explored the role of PSG from natural Leishmania-sand fly vector combinations by obtaining PSG from Leishmania (L.) major-infected Phlebotomus (P.) papatasi and P. duboscqi and L. tropica-infected P. arabicus. We found that, in addition to the vector's saliva, the PSG from L. major and L. tropica potently exacerbated cutaneous infection in BALB/c mice, improved the probability of developing a patent cutaneous lesion, parasite growth and the evolution of the lesion. Of note, the presence of PSG in the inoculum more than halved the prepatent period of cutaneous L. tropica infection from an average of 32 weeks to 13 weeks. In addition, L. major and L. tropica PSG extracted from the permissive experimental vector, Lutzomyia (Lu.) longipalpis, also exacerbated infections in mice. These results reinforce and extend the hypothesis that PSG is an important and evolutionarily conserved component of Leishmania infection that can be used to facilitate experimental infection for drug and vaccine screening.

Visceral leishmaniasis is an important neglected parasitic disease that is generally caused by Leishmania infantum, Leishmania donovani and Leishmania chagasi. However, several causative species of cutaneous leishmaniasis (CL) causes an interstitial form of leishmaniasis which known viscerotropic leishmaniasis. The aim of this paper is a systematic review of the cases of viscerotropic leishmaniasis to present the main causative agents, clinical manifestations, treatment and outcomes of the cases. An electronic search (any date to August 2017) without language restrictions was performed using Medline, PubMed, Scopus and Google Scholar. The searches identified 19 articles with total 30 case reports. Of them, old world Leishmania species was reported from 23 (76.7%) cases, including 20 cases of L. tropica and three cases of L. major; whereas new world Leishmania species were reported in seven (23.4%) cases. The infection was more prevalent in male (24/30, 80%) than female (5/30, 16.7%) patients. Co-morbidity/co-infection was observed in 13 out of 30 cases (43.4%), which the most of them was HIV/AIDS (10 out of 13 cases, 76.9%). The results suggested that viscerotropic leishmaniasis should be more attended in the endemic countries of CL and in immunocompromised patients in order to exact discrimination from other endemic infectious diseases.

Green fluorescent protein (GFP)-parasite transfectants have been widely used as a tool for studying disease pathogenesis in several protozoan models and their application in drug screening assays has increased rapidly. In the past decade, the expression of GFP has been established in several Leishmania species, mostly for in vitro studies. The current work reports generation of four transgenic parasites constitutively expressing GFP (Leishmania mexicana, Leishmania aethiopica, Leishmania tropica and Leishmania major) and their validation as a representative model of infection. This is the first report where stable expression of GFP has been achieved in L. aethiopica and L. tropica. Integration of GFP was accomplished through homologous recombination of the expression construct, pRib1.2αNEOαGFP downstream of the 18S rRNA promoter in all species. A homogeneous and high level expression of GFP was detected in both the promastigote and the intracellular amastigote stages. All transgenic species showed the same growth pattern, ability to infect mammalian host cells and sensitivity to reference drugs as their wild type counterparts. All four transgenic Leishmania are confirmed as models for in vitro and possibly in vivo infections and represent an ideal tool for medium throughput testing of compound libraries.

The aim of the study was the construction of risk maps for exposure to Phlebotomus sergenti, the main vector of Leishmania tropica, with a view to identifying hot spots for the potential establishment of this parasite in the southwest of Europe. Data were collected on the presence/absence of this vector and the ecological and climatic characteristics of 662 sampling sites located in the southeast, centre and northeast of the Iberian Peninsula (south-western Europe). The environmental factors associated with the distribution of P. sergenti were determined. The best predictors for the presence of this dipteran were ‘altitude’, ‘land use’, ‘land surface temperature’, ‘aspect’, ‘adjacent land cover’, ‘absence of vegetation in wall’ and the ‘absence of PVC pipes in the drainage holes of retaining walls’. Risk maps for exposure to the vector were drawn up based on these variables. The validation of the predictive risk model confirmed its usefulness in the detection of areas with a high risk of P. sergenti being present. These locations represent potential hot spots for an autochthonous focus of L. tropica becoming established. The risk maps produced for P. sergenti presence revealed several areas in the centre and south of the Iberian Peninsula to be the most prone to this process, which would make it possible for the disease to enter south-western Europe.

Riboprinting is one of several molecular methods that can generate comparative data independently of the complexity of the organism's morphology. Restriction fragment length polymorphism (RFLP) profiles derived from digestion of polymerase chain reaction (PCR) products of the ribosomal 18S from Leishmania spp. yields a typical ‘riboprint’ profile that can vary intraspecifically. A selection of 76 stocks of L. major and L. tropica, isolated from patients with cutaneous leishmaniasis, was analysed by riboprinting to assess divergence within and between species. L. major and L. tropica could be easily differentiated from each other. Analysis of PCR–RFLP profiles indicated that stocks of Leishmania spp. could be broadly partitioned into 2 species corresponding to L. major and L. tropica. To test if ribosomal 18S sequences were homogeneous within each species, several isolates of each of the Leishmania spp. were digested. Interpretation of the riboprint profiles of the 18S independently amplified by PCR, there would appear to be one restriction pattern present within each Leishmania spp. Homogeneity within copies of the ribosomal 18S within a single genome has, therefore, been demonstrated. The species designation established by riboprinting results were in agreement with the zymodeme analysis of the same isolates. The restriction patterns produced were simple, reproducible and easy to interpret.

The vectorial competence of Phlebotomus sergenti for 3 Old World species of Leishmania, L. tropica, L. major and L. donovani, was investigated in vivo and by in vitro midgut binding assays using living promastigotes and purified lipophosphoglycan (LPG). P. sergenti consistently showed a high specificity for L. tropica strains, which were able to develop mature, potentially transmissible infections. The loss of infection with L. major and L. donovani correlated with the excretion of the digested bloodmeal. These strains were able to produce sustained infections in the midguts of their appropriate vectors, P. papatasi and P. argentipes, respectively. In in vitro binding assays, a significantly higher number of L. tropica procyclic promastigotes attached to the midgut lining of P. sergenti, compared to those of L. major and L. donovani (P < 0·05). The prediction that the species specificity of midgut attachment is controlled by polymorphic structures on the parasite LPG was supported by the finding that P. sergenti midguts were intensely stained following incubation with purified phosphoglycan (PG) from L. tropica compared with PGs from L. major or L. donovani. The results provide further evidence that LPG structural polymorphisms are driven by the species diversity of molecules present on the sandfly midgut that function as parasite attachment sites.