Asymptomatic Leishmania Infected Children: A Seroprevalence and Molecular Survey in a Rural Area of Fars Province, Southern Iran

Leishmania major Infection in Synanthropic Rodents: Evidence for the Urbanization of Zoonotic Cutaneous Leishmaniasis (ZCL) in Southern Iran

Cutaneous leishmaniasis is of particular importance in southern Iran. This study aimed to investigate the infection of rodents with Leishmania major in an urban area of Fars Province, located in southern Iran. Rodents were trapped and samples from the liver, spleen, and skin were collected. Impression smears were prepared from these tissues and any skin lesions and were examined microscopically. In addition, a portion of the samples were preserved for subsequent DNA extraction. A total of 41 rodents belonging to three species were caught from 10 trapping stations in gardens or houses within the area. The caught rodent species were Rattus rattus (n = 25, 60.97%), Mus musculus (n = 15, 36.58%), and Meriones persicus (n = 1, 2.5%). Leishmania amastigotes were seen in the spleen tissue smear of 6 (2.43%) of the rodents, including 4 of R. rattus and 2 of M. musculus. Skin lesions were observed on the muzzles of two R. rattus and one M. musculus. Samples taken from these lesions tested positive for Leishmania infection. Leishmania DNA was detected in 18 (43.9%) rodents, including 11 R. rattus, 6 M. musculus, and one M. persicus, based on DNA sequencing of the ITS2 gene and PCR of the kDNA. Phylogenetic reconstruction revealed that the parasite infecting the rodents was L. major. The detection of Leishmania infection in these rodents in urban areas raises concerns about the urbanization of cutaneous leishmaniasis caused by L. major. This urbanization poses unique challenges for control and prevention efforts.

Management of Liver Hydatid Cysts: A Retrospective Analysis of 293 Surgical Cases from Southern Iran

Background

The current study aimed to evaluate the therapeutic features and complications of liver hydatid cyst in patients who underwent surgery for cystic echinococcosis (CE) in Fars province, southern Iran.

Methods

A total of 293 patients who underwent surgery for liver hydatid cyst from 2004 to 2018 in Fars province, southern Iran, were retrospectively evaluated. The clinical records of patients were reviewed, and the demographic and clinical characteristics of each patient were assessed.

Results

Of the total of 293 cases, 178 (60.9%) were females and 115 (39.1%) were males. The mean age of the subjects was 37.22 (±20.55) years. The mean size of the liver hydatid cyst was 9.18 (±4.365) cm. Of the 293 patients studied, 227 (77.4%) had hydatid cysts only in the liver, while 55 (9.4%) had both liver and lung cysts. More than half of the liver cysts (65.9%) were located in the right portion of the liver (segment 5 to 8). Of the 293 cases, 52 (17.7%) underwent radical surgery, while 241 (82.3%) underwent conservative surgery. Recurrence of hydatid cyst was recorded in 46 (15%) of cases. Patients who were treated with radical surgery in comparison with those who had conservative surgery had a lower recurrence rate but a longer duration of hospital stay (P < 0.05).

Conclusion

Recurrence remains as one of the major challenges in the management of hydatid cyst. Radical surgery reduces the chance of recurrence, although this procedure increases the length of hospital stay.

Asymptomatic Leishmania infection in humans: A systematic review

BACKGROUND

Leishmaniasis is a highly prevalent neglected tropical disease. It mainly presents as two forms: cutaneous and visceral leishmaniasis, the latter being the most severe form. However, asymptomatic cases of Leishmania infection result in an increase in the underreporting and transmission of the protozoan OBJECTIVES: In this study, articles on the incidence of asymptomatic Leishmania infection were systematically reviewed.

METHODS

The publications identified in the Medline/PubMed and Science Direct databases included 4568 articles. Inclusion, exclusion, and eligibility criterion analysis resulted in 83 articles being retained. These studies were mostly performed in Brazil (n = 26) and India (n = 15).

RESULTS

Several detection techniques have been used for diagnosis. Among the species found were L. infantum and L. donovani, which result in visceral leishmaniasis, and L. amazonensis, L. braziliensis, and L. panamensis. The incidence rates varied between the analyzed locations, largely due to sampling and the presence or absence of endemism in the regions. The largest populations analyzed were in two studies performed in India and Nepal. One of these studies evaluated 32,529 people and the incidence rate was 8.3% (n = 2702), while the other study evaluated 21,267 people and the incidence rate was 1.76% (n = 375). Only 14.28% of the studies investigated leishmaniasis in blood donors. Preexisting diseases have also been reported.

CONCLUSION

The findings of this systematic review present the incidence of cases of asymptomatic Leishmania infection worldwide, in addition to detailing the studies and offering information for researchers and health authorities to seek alternatives to reduce the number of leishmaniasis cases.

Identification of asymptomatic Leishmania infections: a scoping review

BACKGROUND

Asymptomatic Leishmania infection may play an important role in the transmission of the parasite in endemic areas. At present there is no consensus on the definition of asymptomatic Leishmania infection, nor is there a safe and accessible gold standard test for its identification.

METHODS

This paper presents a scoping review to summarize definitions of asymptomatic Leishmania infection found in the literature, as well as to detail the approach (molecular, serological, cellular, and/or parasitological tests) used by researchers to identify this asymptomatic population. A scoping review of published and gray literature related to asymptomatic Leishmania infection was conducted; retrieved citations were screened based on predefined eligibility criteria, and relevant data items were extracted from eligible articles. The analysis is descriptive and is presented using tables, figures, and thematic narrative synthesis.

RESULTS

We conducted a screening of 3008 articles, of which 175 were selected for the full review. Of these articles, we selected 106 that met the inclusion criteria. These articles were published between 1991 and 2021, and in the last 5 years, up to 38 articles were reported. Most of the studies were conducted in Brazil (26%), Spain (14%), India (12%), Bangladesh (10%), and Ethiopia (7%). Of the studies, 84.9% were conducted in the immunocompetent population, while 15.1% were conducted in the immunosuppressed population (HIV, immunosuppressive drugs, and organ transplantation population). We report 14 different techniques and 10 strategies employed by researchers to define asymptomatic Leishmania infection in an endemic area.

CONCLUSIONS

The definition of asymptomatic Leishmania infection is not unified across the literature, but often includes the following criteria: residence (or extended stay) in a Leishmania-endemic area, no reported signs/symptoms compatible with leishmaniasis, and positive on a combination of serological, molecular, cellular, and/or parasitological tests. Caution is recommended when comparing results of different studies on the subject of asymptomatic infections, as the reported prevalence cannot be confidently compared between areas due to the wide variety of tests employed by research groups. More research on the importance of asymptomatic immunosuppressed and immunocompetent Leishmania-positive populations in leishmaniasis epidemiology is required.

Stereological analysis of liver, spleen and bone of Leishmania infantum-experimentally infected hamsters

Leishmaniasis is remaining as one of the important health problems of many countries around the world. The histopathology of the disease and the effects of the parasite on various tissues have not yet been fully elucidated. The current study aimed to evaluate the stereological features of the liver, spleen, and bone of hamsters infected with Leishmania infantum. In this experimental study, the L. infantum parasite was mass cultivated in a culture medium. Then, 15 golden hamsters were selected, of which 5 animals were considered as controls and another 10 animals were injected intravenously, with 1 × 10⁸ promastigotes of L. infantum. Four months later, the hamsters were euthanized and impression smears were prepared from the liver and spleen. Moreover, pathology slides were prepared from the spleen, liver, and femur. The orientated method was used to obtain isotropic uniform random (IUR) sections. For stereological evaluation, the tissues were fixed with formalin buffer, and sections (4 and 25 μm thick) were prepared and stained with Heidenhain's AZAN trichrome and hematoxylin-eosin, respectively. The tissue samples were examined by stereological methods and all changes in the samples of the infected hamsters were compared with the control group. The number of hepatocyte and their nuclei volumes were significantly decreased in the Leishmania-infected group, compared to the control group. The number of Kupffer cells and their volume in the liver of the Leishmania-infected group was higher than that of the control group, and the differences were statistically significant. The volume of trabeculae and central arteries in the spleen of the Leishmania-infected group was lower than that of the control group and the number of lymphocytes and macrophages in the spleen of the Leishmania-infected group was increased compared to the control group. The trabecular volume and the number of osteoblasts and osteoclasts of the femur in Leishmania-infected animals decreased, whereas the volume of bone marrow was significantly raised. Leishmaniasis leads to changes in tissue structure and their function in the host by the involvement of various organs of the immune system including the liver, spleen, and bone. Understanding these changes are important in identifying the effective mechanisms of the parasite and host interaction.

The Geographical Distribution of Human Cutaneous and Visceral Leishmania Species Identified by Molecular Methods in Iran: A Systematic Review With Meta-Analysis

Leishmaniasis is one of the most common vector-borne parasitic diseases in Iran. Leishmania species identification is necessary for epidemiological aspects, precise prognosis, control and treatment of the disease. We systematically searched all the studies, reports, and documentation related to species identification and geographical distribution of causative agents of cutaneous (CL), mucosal (ML), and visceral leishmaniasis (VL) using DNA-based molecular diagnostic techniques in Iran. International databases including PubMed, ScienceDirect, Embase, Google Scholar, Scopus, and Web of Science were systemically searched for English articles and Iran's databases including SID, IranMedex and Magiran were searched for Persian reports and articles. Searches were performed from 1999 to 2019 (20 years). The current review was conducted using the keywords: cutaneous leishmaniasis, visceral leishmaniasis, Leishmania species, Human, Molecular, PCR, and Iran. The study quality was evaluated using the NOS checklist. This meta-analysis procedure was accomplished using STATA, version 2.7.9. Of the 3,426 records identified in the initial search, 154 articles met inclusion criteria and qualified for the systematic review and meta-analysis. In subgroup analysis, the pooled frequency of causative agents of CL isolates was 67.3% (95% CI: 59.51–74.67%) for L. major and 32.1% (95% CI: 24.72–39.87%) for L. tropica. In addition, the pooled frequency of causative agents of VL isolates was 97.1% (95% CI: 94.6–98.8%) for L. infantum and 2.9% (95% CI: 1.12–5.37%) for L. tropica. The findings of this study showed that the main causative agents of CL and VL in Iran are L. major and L. infantum, respectively. Moreover, kinetoplast DNA (kDNA) and internal transcriber spacer (ITS) were the most used markers for identifying Leishmania species. The current study provides valuable data to encourage and direct researchers as well as public health managers in the comprehensive leishmaniasis control and prevention planning in Iran.

Molecular and serological evaluation of zoonotic visceral leishmaniasis in dogs in a rural area of Fars province, southern Iran, as a source of Leishmania infantum infection

Canine visceral leishmaniasis (CVL) is endemic in the southern parts of Iran. The current study aimed at molecular and serological evaluation of zoonotic visceral leishmaniasis in dogs in Fars province, southern Iran. Blood samples were collected from 60 dogs in the three villages in Fars Province. Serum samples were tested for antibodies against L. infantum by direct agglutination test (DAT). DNA was extracted from each dog's buffy coat and tested by PCR, targeting the Leishmania ITS‐2 region. From a total of 60 studied dogs, 25 (41.7%) were female, and 35 (58.3%) were male. Dogs' age ranged from 1 to 7 years, with a mean age of 2.97 (±1.4) years. Anti‐Leishmania antibodies were detected in sera samples of 28 (46.7%) dogs, (titre ≥ 1:320). Out of 28 seropositive cases, 13 (46.4%) were female, and 15 (53.6%) were male. Association between seropositivity and dogs’ clinical signs was statistically significant (p < .05). Leishmania DNA was detected in the buffy coat of 3 of 60 studied dogs which were all seropositive by DAT. The PCR products were sequenced and molecular analysis showed that two of the isolates were Leishmania infantum, and one was L. tropica. The high proportion of seropositive dogs indicates the important role of these animals in the epidemiology of the disease in the region. Infected dogs with or without signs, especially those that are molecularly positive, can act as an active reservoir of the disease in the area.

Visceral leishmaniasis in an adult case in Northeast of Iran: A case report and literature review

Leishmaniasis is a rare complication in adult cases even in endemic areas. Here, the first report of visceral leishmaniasis in a young woman in northeast of Iran has been described.

Leishmania ITS1 Is Genetically Divergent in Asymptomatic and Symptomatic Visceral Leishmaniasis: Results of a Study in Southern Iran

It has been documented that the genotypic traits in symptomatic and asymptomatic cases of visceral leishmaniasis (VL) may be different. The current study aimed to find out and compare the genotype and intraspecies diversity of Leishmania Internal Transcribed Spacer 1 (ITS1) from asymptomatic and symptomatic VL cases in southern Iran. Methods. Buffy coat samples from seven VL patients, with clinical signs and symptoms, and seven asymptomatic VL cases, were evaluated in this study. Samples of asymptomatic individuals were obtained from children living in a VL endemic area in southern Iran, while the samples of symptomatic subjects were obtained from patients admitted to hospitals with a diagnosis of VL. DNA was extracted from the buffy coats of the samples and PCR-amplified, targeting the ITS1of Leishmania. The PCR products were sequenced, and the consensus sequences were assembled and multiple-aligned with a set of Leishmania strains retrieved from the GenBank, using Clustal W. The phylogenetic tree was rooted, using MEGAX software, and the diversities based on haplotype and nucleotides, as well as the number of polymorphic sites, were measured using DnaSP v5.0 software. The results of ITS1 sequencing in 5 out of 7 asymptomatic VL cases showed 99.25% to 100% similarity with the Leishmania infantum ITS1 sequence (accessed number: MN648746), and one isolate was considered as just Leishmania sp. In one sample, 99.75% similarity was seen with the ITS1 sequence of Crithidia fasciculata. Of the symptomatic VL patients, the PCR product revealed a 340 bp band corresponding to L. infantum in all of the samples. By analyzing the ITS1 sequences, all seven sequences formed a clade somewhat different from other Leishmania species and considered as Leishmania sp. Haplotype and nucleotide diversity were much more prevalent in symptomatic cases where six haplotypes were seen in the ITS1 of Leishmania from symptomatic patients and only two haplotypes were observed in the samples from asymptomatic cases. The findings of the current study showed that the Leishmania ITS1 from symptomatic VL and asymptomatic cases has significant genetic differences. Besides, infection with Crithidia fasciculata was reported, for the first time, in an asymptomatic case, which deserves further study.

Seroepidemiological study on visceral leishmaniasis in an endemic focus of central Iran during 2017

Visceral leishmaniasis (VL) is a serious parasitic disease that occurs in some areas of Iran as endemic and sporadic forms. Qom province in central Iran is one of the endemic foci of VL, which is an important issue due to existence of local population density, foreign travelers and resided migrants. This descriptive cross-sectional study that was conducted with the aim of evaluating seroprevalence of VL in the studied area. The research considers various risk factors like immigration and tourism for planning prevention and disease control programs. Random cluster sample selection applied and 960 blood samples collected from children up to 12 years of age. The samples were taken from 22 villages in four clusters, during 2017. A questionnaire was given to each individual after obtaining parental consent. All collected sera assessed by Direct Agglutination Test to detect anti-Leishmania infantum antibodies. The antibody titers of ≥ 1:3200, accompanied by clinical symptoms, considered as VL disease. Eventually, 3 (0.3%) cases showed anti-L. infantum antibodies with titers of ≥ 1:1600, while 2 of them (0.2%) had antibody titers of 1:3200 with no clinical manifestations. In order to investigate the increase of antibody, resampling performed after 2-3 weeks in which no antibody rising observed. The findings indicate that distribution pattern of VL is changing from endemic to sporadic form in rural areas of Qom province. Therefore, it is necessary to continue the surveillance by public health centers besides conducting further studies on VL reservoirs and vectors with the aim of VL control in the area.

High frequency of subclinical Leishmania infection among HIV-infected patients living in the endemic areas of visceral leishmaniasis in Fars province, southern Iran

Visceral leishmaniasis (VL) is a major health concern in patients with HIV infection in endemic areas of VL. In these areas, a substantial number of infected individuals are asymptomatic and the risk of acute VL infection in HIV/VL co-infected cases is high. The current study aimed to determine the prevalence of asymptomatic VL infection among HIV-infected patients in Fars province, southern Iran. Subjects of the study were 251 HIV-confirmed patients who all were clinically asymptomatic for leishmaniasis. Blood samples were obtained from each participant. Anti-Leishmania antibodies were detected in the sera using ELISA. DNA was extracted from the buffy coat of each subject and PCR amplified, targeting an ITS-2 gene of Leishmania. PCR products were purified from the gel and were sequenced. Overall, 19 out of 251 (7.6%) HIV-infected patients were found to be infected with Leishmania, using serological or molecular methods. Anti-Leishmania antibodies were detected in 13 (5.2%) patients and leishmanial DNA in 8 (3.2%) of the patients. The sequence analysis of DNA-positive cases revealed the species of the parasite as L. infantum. The high prevalence of VL among the patients with HIV is a serious challenge which demands further attention to improve the prophylaxis and treatment measurements of VL/HIV co-infection and thereby promoting the life expectancy and quality of life of these patients.

Immunodiagnosis of Visceral Leishmaniasis: Current Status and Challenges: A Review Article

BACKGROUND

Diagnosis of Visceral Leishmaniasis (VL) is still challenging. This review highlighted current status and challenges in the serological diagnosis of VL. Furthermore, the drawback of currently available serological tests and the most recent advancement in the designing and application of these assays for the diagnosis of VL are addressed.

METHODS

All the published literature cited within PubMed, ISI Web of Science, Google Scholar, Scopus, and IranMedex, regarding the immunodiagnosis of VL in human were sought from 2000 till Mar 2017. The search terms were "visceral leishmaniasis", or "kala-azar" subsequently combined with the search terms "diagnosis", "serodiagnosis", "human", "serological", "antigen detection" or "antibody detection". Data were extracted from literature which fulfilled our eligibility criteria.

RESULTS

Direct agglutination test (DAT) and rk39 dipstick have made a great improvement in the serological diagnosis of VL. Besides, other kinesin-related protein including K26, K28, and KE16 provided promisingly diagnostic accuracy in the diagnosis of VL. The Latex Agglutination Test for the diagnosis of VL (KAtex), with moderate sensitivity but high specificity, made a substantial contribution to the field. Moreover, a range of protein antigens has recently been detected in the urine of VL patients with encouraging diagnostic value.

CONCLUSION

The suboptimal diagnostic accuracy of the currently available serological assays for the diagnosis of human VL necessitates further research and development in this field. Outcomes of immunodiagnostic tests based on recombinant antigens are favorable. These proteins might be the most appropriate antigens to be further evaluated and utilized for the diagnosis of human VL.