Identification of Leishmania strains from Jordan

Leishmania major cutaneous leishmaniasis outbreak in the Jordanian side of the Northern Jordan Valley

Cutaneous leishmaniasis (CL) is endemic in many foci of Jordan and the Jordanian Mid Jordan Valley (JMJV) is the most affected and the incidence is quite high. The situation in the northern part of the Jordanian side of the Jordan Valley (NJJV) was different; before 2008, CL has rarely been reported from this area. From April 2008 to May 2009, passive detection followed by active detection was used to trace cases of CL from the NJJV. DNA was extracted from seven clinical isolates of Leishmania promastigotes and lesion scrapings spotted on filter papers obtained from 51 suspected CL patients living in the NJJV. The identity of the causative species of CL in the NJJV was investigated using ITS1-PCR followed by RFLP. In 2008/2009, 183 cases were clinically diagnosed of having CL in the NJJV. The parasites in five of the isolates and in 48 PCR-positive scrapings were classified as Leishmania major. In two isolates and in one PCR-positive scraping Leishmania tropica was identified. Investigations on the origin of CL cases revealed that the L. tropica cases were residents of two towns outside the NJJV. Herein, we report the clinical features, parasitological diagnosis, etiology, and the geographical distribution of CL cases from NJJV with the aim of documenting, for the first time, an outbreak in this area.

The Montpellier Leishmania Collection, from a Laboratory Collection to a Biological Resource Center: A 39-Year-Long Story

We report the development of a laboratory collection of Leishmania that was initiated in 1975 and, after 39 years, has become an international Biological Resource Center (BRC-Leish, Montpellier, France, BioBank No. BB-0033-00052), which includes 6353 strains belonging to 36 Leishmania taxa. This is a retrospective analysis of the technical and organizational changes that have been adopted over time to take into account the technological advances and related modifications in the collection management and quality system. The technical improvements concerned the culture and cryopreservation techniques, strain identification by isoenzymatic and molecular techniques, data computerization and quality management to meet the changes in international standards, and in the cryogenic and microbiological safety procedures. The BRC is working toward obtaining the NF-S 96-900 certification in the coming years. Our long-term expertise in Leishmania storage and typing and collection maintenance should encourage field epidemiologists and clinical practitioners in endemic countries to secure their own strain collection with the help of the French BRC-Leish.

Molecular Diagnosis and Identification of Leishmania Species in Jordan from Saved Dry Samples

Diagnosis of the endemic cutaneous leishmaniasis (CL) in Jordan relies on patient clinical presentation and microscopic identification. Studies toward improved identification of the causative Leishmania species, especially in regions where multiple species exist, and the introduction of these techniques into medical diagnosis is paramount. This study looked at the current epidemiology of CL in Jordan. Clinically diagnosed 41 patients with CL were tested for the presence of Leishmania parasite using both Giemsa staining from skin scraps on glass slides and ITS1-PCR from samples blotted onto storage cards (NucleoCards®). Microscopically, 28 out of the 41 (68.3%) collected samples were positive for amastigotes, whereas the molecular ITS1-PCR amplification successfully identified 30 of the 41 samples (73.2%). Furthermore, PCR-RFLP analysis allowed species identification which is impossible microscopically. Of the 30 PCR positive samples, 28 were Leishmania major positive and the other two samples were Leishmania tropica. This indicates that L. major is the most prevalent species in Jordan and the two L. tropica cases originated from Syria indicating possible future L. tropica outbreaks. Diagnosis of CL based on clinical presentation only may falsely increase its prevalence. Although PCR is more sensitive, it is still not available in our medical laboratories in Jordan.

Phlebotomus papatasi SP15: mRNA expression variability and amino acid sequence polymorphisms of field populations

Background

The Phlebotomus papatasi salivary protein PpSP15 was shown to protect mice against Leishmania major, suggesting that incorporation of salivary molecules in multi-component vaccines may be a viable strategy for anti-Leishmania vaccines.

Methods

Here, we investigated PpSP15 predicted amino acid sequence variability and mRNA profile of P. papatasi field populations from the Middle East. In addition, predicted MHC class II T-cell epitopes were obtained and compared to areas of amino acid sequence variability within the secreted protein.

Results

The analysis of PpSP15 expression from field populations revealed significant intra- and interpopulation variation.. In spite of the variability detected for P. papatasi populations, common epitopes for MHC class II binding are still present and may potentially be used to boost the response against Le. major infections.

Conclusions

Conserved epitopes of PpSP15 could potentially be used in the development of a salivary gland antigen-based vaccine.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-0914-2) contains supplementary material, which is available to authorized users.

Leishmaniasis in the middle East: incidence and epidemiology

Leishmaniasis is a major health problem worldwide, with several countries reporting cases of leishmaniasis resulting in loss of human life or a lifelong stigma because of bodily scars. The Middle East is endemic for cutaneous leishmaniasis, with countries like Syria reporting very high incidence of the disease. Despite several countries establishing national control programs for containing the sandfly vector and treatment of infection, the disease continues to spread. In addition to the endemicity of the region for leishmaniasis, the Middle East has seen a great deal of human migration either for earning of livelihood or due to political upheaval in the region. These factors contribute to the spread and proliferation of the causative species Leishmania and its sandfly host. This review discusses the current epidemiological scenario in Iraq, Syria, Saudi Arabia, and Jordan, emphasizing the number of cases reported, vector species, Leishmania species, and treatment available. The data is primarily from WHO reports for each country and current and old literature.

Profiling of human acquired immunity against the salivary proteins of Phlebotomus papatasi reveals clusters of differential immunoreactivity

Phlebotomus papatasi sand flies are among the primary vectors of Leishmania major parasites from Morocco to the Indian subcontinent and from southern Europe to central and eastern Africa. Antibody-based immunity to sand fly salivary gland proteins in human populations remains a complex contextual problem that is not yet fully understood. We profiled the immunoreactivities of plasma antibodies to sand fly salivary gland sonicates (SGSs) from 229 human blood donors residing in different regions of sand fly endemicity throughout Jordan and Egypt as well as 69 US military personnel, who were differentially exposed to P. papatasi bites and L. major infections in Iraq. Compared with plasma from control region donors, antibodies were significantly immunoreactive to five salivary proteins (12, 26, 30, 38, and 44 kDa) among Jordanian and Egyptian donors, with immunoglobulin G4 being the dominant anti-SGS isotype. US personnel were significantly immunoreactive to only two salivary proteins (38 and 14 kDa). Using k-means clustering, donors were segregated into four clusters distinguished by unique immunoreactivity profiles to varying combinations of the significantly immunogenic salivary proteins. SGS-induced cellular proliferation was diminished among donors residing in sand fly-endemic regions. These data provide a clearer picture of human immune responses to sand fly vector salivary constituents.

Development of assays using hexokinase and phosphoglucomutase gene sequences that distinguish strains of Leishmania tropica from different zymodemes and microsatellite clusters and their application to Palestinian foci of cutaneous leishmaniasis

Background/Objectives

Palestinian strains of L.tropica characterized by multilocus enzyme electrophoresis (MLEE) fall into two zymodemes, either MON-137 or MON-307.

Methodology/Principle Findings

Assays employing PCR and subsequent RFLP were applied to sequences found in the Hexokinase (HK) gene, an enzyme that is not used in MLEE, and the Phosphoglucomutase (PGM) gene, an enzyme that is used for MLEE, to see if they would facilitate consigning local strains of L.tropica to either zymodeme MON-137 or zymodeme MON-307. Following amplification and subsequent double digestion with the restriction endonucleases MboI and HaeIII, variation in the restriction patterns of the sequence from the HK gene distinguished strains of L.tropica, L.major and L.infantum and also exposed two genotypes (G) among the strains of L.tropica: HK-LtG1, associated with strains of L.tropica of the zymodemes MON-137 and MON-265, and HK-LtG2, associated with strains of L.tropica of the zymodemes MON-307, MON-288, MON-275 and MON-54. Following amplification and subsequent digestion by the restriction endonuclease MboI, variation in the sequence from the PGM gene also exposed two genotypes among the strains of L.tropica: PGM-G1, associated only with strains of L.tropica of the zymodeme MON-137; and PGM-G2, associated with strains of L.tropica of the zymodemes MON-265, MON-307, MON-288, MON-275 and MON-54, and, also, with six strains of L.major, five of L.infantum and one of L.donovani. The use of the HK and PGM gene sequences enabled distinction the L.tropica strains of the zymodeme MON-137 from those of the zymodeme MON-265. This genotyping system ‘correctly’ identified reference strains of L.tropica of known zymodemal affiliation and also from clinical samples, with a level of sensitivity down to <1 fg in the case of the former and to 1 pg of DNA in the case of the latter.

Conclusions/Significance

Both assays proved useful for identifying leishmanial parasites in clinical samples without resource to culture and MLEE.

The species L. major, L. tropica and L. infantum exist in Palestine and Israel where the first two cause CL and the third usually causes VL although cases of CL without visible signs of VL have been reported from Palestine. This means that diagnosis of locally acquired leishmaniases requires identification of their causative agents for further management of cases. Two molecular biological methods based on sequences from the genes of the enzymes HK and PGM and employing PCRs and consecutive RFLPs were developed and used together to distinguish among strains of the three species and between the two subtypes of L. tropica found in Palestinian foci that coincide with zymodemes MON-137 and MON-307. They were applied to, both, isolated parasites grown as promastigotes and to amastigotes in tissue preparations from cases and were able to identify strains and indicate their zymodemal affiliations.

Genetic, serological and biochemical characterization of Leishmania tropica from foci in northern Palestine and discovery of zymodeme MON-307

BACKGROUND

Many cases of cutaneous leishmaniasis (CL) have been recorded in the Jenin District based on their clinical appearance. Here, their parasites have been characterized in depth.

METHODS

Leishmanial parasites isolated from 12 human cases of CL from the Jenin District were cultured as promastigotes, whose DNA was extracted. The ITS1 sequence and the 7SL RNA gene were analysed as was the kinetoplast minicircle DNA (kDNA) sequence. Excreted factor (EF) serotyping and multilocus enzyme electrophoresis (MLEE) were also applied.

RESULTS

This extensive characterization identified the strains as Leishmania tropica of two very distinct sub-types that parallel the two sub-groups discerned by multilocus microsatellite typing (MLMT) done previously. A high degree of congruity was displayed among the results generated by the different analytical methods that had examined various cellular components and exposed intra-specific heterogeneity among the 12 strains.Three of the ten strains subjected to MLEE constituted a new zymodeme, zymodeme MON-307, and seven belonged to the known zymodeme MON-137. Ten of the 15 enzymes in the profile of zymodeme MON-307 displayed different electrophoretic mobilities compared with the enzyme profile of the zymodeme MON-137. The closest profile to that of zymodeme MON-307 was that of the zymodeme MON-76 known from Syria.Strains of the zymodeme MON-307 were EF sub-serotype A2 and those of the zymodeme MON-137 were either A9 or A9B4. The sub-serotype B4 component appears, so far, to be unique to some strains of L. tropica of zymodeme MON-137. Strains of the zymodeme MON-137 displayed a distinctive fragment of 417 bp that was absent in those of zymodeme MON-307 when their kDNA was digested with the endonuclease RsaI. kDNA-RFLP after digestion with the endonuclease MboI facilitated a further level of differentiation that partially coincided with the geographical distribution of the human cases from which the strains came.

CONCLUSIONS

The Palestinian strains that were assigned to different genetic groups differed in their MLEE profiles and their EF types. A new zymodeme, zymodeme MON-307 was discovered that seems to be unique to the northern part of the Palestinian West Bank. What seemed to be a straight forward classical situation of L. tropica causing anthroponotic CL in the Jenin District might be a more complex situation, owing to the presence of two separate sub-types of L. tropica that, possibly, indicates two separate transmission cycles involving two separate types of phlebotomine sand fly vector.