Reemergence of zoonotic cutaneous leishmaniasis in an endemic focus, northeastern Iran

A Geomedical Survey: Is There an Association Between Climatic Conditions and Leishmania Species Distribution in Iran During the Years 1999-2021?

PURPOSE

Iran is among the high-risk leishmaniasis regions in the world. WHO recommends the use of GIS as an ideal tool for healthcare authorities to predict the evolution of a disease, delimit the risk of outbreaks and identify critical areas. The aim of this research is to find the association between the main species of Leishmania (L. major, L. tropica, L. infantum) dispersion and climatic variables in Iran.

METHODS

All molecular-based reports of leishmaniasis from Iran between 1999 and 2021 were gathered from reliable medical sources. Meteorological data (air and soil temperatures, annual rainfall and humidity) of the country along the study period were obtained from the Iranian Climatological Research Centre. The data concerning species distribution and climatic conditions during this period were moved to a base-map through raster layers using ArcGIS 10.4.1 software. The relationship between parasitological and climatic models was examined using ANOVA.

RESULTS

High risk area maps, based on the cut-off thresholds, were generated for Leishmania major, L. tropica and L. infantum. According to the molecular-based reports, the L. major distribution was significantly related to all climatic variables, while L. tropica was merely related to rainfall and humidity, and the L. infantum distribution was significantly associated with rainfall, soil and air temperatures.

CONCLUSION

The association between climatic conditions and Leishmania species distribution in Iran has been confirmed. Consequently, both, the relationship between climatic conditions and the geographical distribution of Leishmania species, and the use of GIS to better understand the spatial epidemiology of leishmaniasis, have been reaffirmed.

Molecular Identification and Phylogenetic Analysis of Leishmania major Isolated from Zoonotic Cutaneous Leishmaniasis Foci in Northeast Iran

Background

Epidemiological studies, classification and genetic studies of Leishmania species are effective in treatment, control and prevention in endemic areas. We aimed to investigate the genetic diversity and phylogeny of Leishmania in Zoonotic foci located in northeastern Iran using nagt gene for the first time.

Methods

DNA of 100 confirmed positive slides collected from the health centers of Sarkhes, Darghez, Fariman, Esfarayen, and Sabzevar were extracted during 2020-2021. The partial sequence of kDNA was amplified to identify the species. Twenty-five DNA samples were randomly subjected to amplify by nagt gene primes and were sequenced. The sequences were aligned with reference sequences in National Center for Biotechnology Information (NCBI). Then, the genetic similarities of the sequences were checked using Clustalx2.1 software and the phylogenetic tree was drawn by Mega 7 software.

Results

All the positive samples were diagnosed as L. major. Approximately, half of the sequences of species were similar to two reference genes JX103550.1:404-712 L. major Esfahan and KX759012.1:568-807 L. Major Ilam (more than 90% similarity). According to the results of the phylogeny tree, the closest genotype to our study samples was JX103550.1:404-712 L. major Esfahan.

Conclusion

The most causative agent CL in these areas was L. major. The genetic diversity of L. major was high such as other zoonotic foci in Iran. Due to the high similarity of the strains in the study areas with the strains of Isfahan and Ilam, similar control and prevention methods is suggested in these areas.

Cutaneous leishmaniasis situation analysis in the Islamic Republic of Iran in preparation for an elimination plan

Iran has invariably been under the growing public health threat of cutaneous leishmaniasis (CL), a significant barrier to local development that hinders the prevention and control efforts toward eliminating the disease. So far, no comprehensive and in-depth epidemiological analysis of the CL situation has been carried out nationwide. This study aimed to employ advanced statistical models to analyze the data collected through the Center for Diseases Control and Prevention of Communicable Diseases during 1989-2020. However, we emphasized the current trends, 2013-2020, to study temporal and spatial CL patterns. In the country, the epidemiology of CL is incredibly intricate due to various factors. This fact indicates that the basic infrastructure, the preceding supports, and the implementation plan related to preventive and therapeutic measures need crucial support. The leishmaniasis situation analysis is consistent with desperate requirements for efficient information on the control program in the area. This review provides evidence of temporally regressive and spatially expanding incidence of CL with characteristic geographical patterns and disease hotspots, signifying an urgent need for comprehensive control strategies. This information could be a suitable model and practical experience in the Eastern Mediterranean Region, where over 80% of CL is reported.

Patterns of cutaneous leishmaniasis during the COVID-19 pandemic in four endemic regions of Iran

BACKGROUND

Both zoonotic cutaneous leishmaniasis (ZCL) and anthroponotic cutaneous leishmaniasis are endemic in different regions of Iran. It is important to know the type of cutaneous leishmaniasis (CL) for prevention strategies. On the other hand, Iran is one of the countries that was severely affected by the coronavirus 2019 (COVID-19) pandemic. However, little is known about the causative agents of CL during the COVID-19 pandemic in Iran.

METHODS

In this study, a total of 181 samples were isolated from patients with CL lesions in four different endemic cities of Iran (Jahrom, Juyom, Kashan and Shoushtar) during the COVID-19 pandemic (the summer and autumn of 2021). The nested-PCR targeting kinetoplast DNA (kDNA) minicircles was applied for species identification of the parasite and the internal transcribed spacer-1 (ITS-1) gene was applied for sequencing and phylogenetic analysis.

RESULTS

Molecular detection of kDNA minicircles revealed that all isolates from the four cities were Leishmania major, indicating the ZCL pattern. Ten isolates were sequenced by the ITS-1 gene and deposited in GenBank [accession numbers: OL627363-72]. Sequencing and phylogenetic analysis displayed a high similarity rate of the isolates with sequences from other parts of Iran and Iraq. Over half of the patients (53.59%) had a single lesion, while 17.12, 14.92, 2.21 and 12.16% of cases had two, three, four and more than four lesions, respectively. About half of the patients (50.27%) had lesions on their hands, while the rest had lesions on multiple locations (19.34%), legs (16.58%), face (9.94%), ears (1.66%) and waist (2.21%).

CONCLUSIONS

This study revealed the occurrence of ZCL during the COVID-19 pandemic in four endemic regions of Iran. Strategies for prevention and control of the disease should be considered to mitigate the occurrence of ZCL.

Seasonal Patterns of Zoonotic Cutaneous Leishmaniasis Caused by L. major and Transmitted by Phlebotomus papatasi in the North Africa Region, a Systematic Review and a Meta-Analysis

BACKGROUND

In North African countries, zoonotic cutaneous leishmaniasis (ZCL) is a seasonal disease linked to Phlebotomus papatasi, Scopoli, 1786, the primary proven vector of L. major dynamics. Even if the disease is of public health importance, studies of P. papatasi seasonal dynamics are often local and dispersed in space and time. Therefore, a detailed picture of the biology and behavior of the vector linked with climatic factors and the framework of ZCL outbreaks is still lacking at the North African countries' level. Our study aims to fill this gap via a systematic review and meta-analysis of the seasonal incidence of ZCL and the activity of P. papatasi in North African countries. We address the relationship between the seasonal number of declared ZCL cases, the seasonal dynamic of P. papatasi, and climatic variables at the North African region scale.

METHODS

We selected 585 publications, dissertations, and archives data published from 1990 to July 2022. The monthly incidence data of ZCL were extracted from 15 documents and those on the seasonal dynamic of P. papatasi from 11 publications from four North African countries.

RESULTS

Our analysis disclosed that for most studied sites, the highest ZCL incidence is recorded from October to February (the hibernal season of the vector), while the P. papatasi density peaks primarily during the hot season of June to September. Overall, at the North African region scale, two to four months laps are present before the apparition of the scars reminiscent of infection by L. major.

CONCLUSIONS

Such analysis is of interest to regional decision-makers for planning control of ZCL in North African countries. They can also be a rationale on which future field studies combining ZCL disease incidence, vector activity, and climatic data can be built.

Leishmania tarentolae as Potential Live Vaccine Co-Expressing Distinct Salivary Gland Proteins Against Experimental Cutaneous Leishmaniasis in BALB/c Mice Model

Leishmaniasis is a neglected vector-borne disease caused by Leishmania parasites transmitted through the infected sand flies bite. Current treatments are limited, partly due to their high cost and significant adverse effects, and no human vaccine is yet available. Sand flies saliva has been examined for their potential application as an anti-Leishmania vaccine. The salivary protein, PpSP15, was the first protective vaccine candidate against L. major. Additionally, PsSP9 was already introduced as a highly immunogenic salivary protein against L. tropica. Herein, we aimed to develop an effective multivalent live vaccine to control Cutaneous Leishmaniasis induced by two main species, L. major and L. tropica. Hence, the two above-mentioned salivary proteins using T2A linker were incorporated inside the L. tarentolae genome as a safe live vector. Then, the immunogenicity and protective effects of recombinant L. tarentolae co-expressing PpSP15 and PsSP9 were evaluated in pre-treated BALB/c mice with CpG against L. major and L. tropica. Following the cytokine assays, parasite burden and antibody assessment at different time-points at pre and post-infection, promising protective Th1 immunity was obtained in vaccinated mice with recombinant L. tarentolae co-expressing PpSP15 and PsSP9. This is the first study demonstrating the potency of a safe live vaccine based on the combination of different salivary proteins against the infectious challenge with two different species of Leishmania.

Ecology of sand flies (Diptera: Psychodidae, Phlebotominae) in Jajarm County, an area with high risk of cutaneous leishmaniasis, in North Khorasan, Iran

The present study was conducted to investigate the ecological aspects of sand flies in southwestern North Khorasan, in which cutaneous leishmaniasis caused by Leishmania major has been reported with the highest annual incidence in Iran. Sampling was carried out in four localities including: Khorasha (natural), Ghamiteh (natural), Jorbat (semi urban) and Brick kilns (urban), twice a month using 105 sticky paper traps from indoors and outdoors dwellings during May-December 2017. Specimens were removed from sticky papers, washed in acetone, preserved in 80% ethanol, mounted on microscopic slides by Puri’s medium, and identified using valid morphological keys. Simpson (D), richness (S), Menhinick (DMg), Margalef (DMn), Shannon-Weiner (H′), evenness (J’) were calculated for species diversity. The synanthropic index was determined for the first time in the area. Totally 517 specimens were collected, 47% in outdoors and 30.4% in human indoor dwellings and 22.6% in animal. Eight species of sand flies including 5 species of the genus Phlebotomus and 3 species of the genus Sergentomyia were identified. Phlebotomus papatasi and Sergentomyia sintoni were the most common and Eudominant species, active in all months, collected in the maximum number and percentage in September and August, respectively, and showed the highest abundance in outdoors. The synanthropic index ranged from 6.25 to 38.9 in the study area. The Shannon-Wiener index was estimated to be up to 1.4 and 1.37 in Khorasha and November, respectively, which showed the highest diversity due to maximal richness and evenness compared to other areas. High abundance of Ph. papatasi, as the main vector of cutaneous leishmaniasis, can enhance the potential risk of emerging CL in new areas, the data can be equally important when vector control measures are considered.