Environmental, climatic and host population risk factors of human cystic echinococcosis in southwest of Iran

Bioclimatic analysis and spatial distribution of fascioliasis causative agents by assessment of Lymnaeidae snails in northwestern provinces of Iran

BACKGROUND

Snails of the Lymnaeidae family are the intermediate hosts of Fasciola species, the causative agents of fascioliasis. The purpose of this study was to determine the prevalence of Fasciola species in lymnaeid snails and to investigate the association of geoclimatic factors and Fasciola species distribution in northwestern provinces of Iran using geographical information system (GIS) data.

METHODS

A total of 2000 lymnaeid snails were collected from 33 permanent and seasonal habitats in northwestern Iran during the period from June to November 2021. After identification by standard morphological keys, they were subjected to shedding and crushing methods. Different stages of Fasciola obtained from these snails were subjected to the ITS1 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for species identification. The associations of weather temperature, rainfall, humidity, evaporation, air pressure, wind speed, elevation, and land cover with the distribution of Fasciola species were investigated. Geographical and statistical analysis was performed using ArcMap and SPSS software, respectively, to determine factors related to Fasciola species distribution.

RESULTS

Of the 2000 snails collected, 19 were infected with Fasciola hepatica (0.09%), six with F. gigantica (0.03%), and 13 with other trematodes. Among geoclimatic and environmental factors, mean humidity, maximum humidity, and wind speed were significantly higher in areas where F. hepatica was more common than F. gigantica. The altitude of F. hepatica-prevalent areas was generally lower than F. gigantica areas. No significant relationship was observed between other investigated geoclimatic factors and the distribution of infected snails.

CONCLUSIONS

The present study showed the relationship of humidity and wind speed with the distribution of snails infected with F. hepatica or F. gigantica in the northwestern regions of Iran. In contrast to F. gigantica, F. hepatica was more prevalent in low-altitude areas. Further research is recommended to elucidate the relationship between geoclimatic factors and the presence of intermediate hosts of the two Fasciola species.

Geographical and climatic risk factors of cutaneous leishmaniasis in the hyper-endemic focus of Bam County in southeast Iran

Introduction

Cutaneous leishmaniasis (CL) is a prevalent debilitating disease in many countries, particularly in Iran, the Middle East, North Africa, and South America. Bam County is the most important highly endemic focus of anthropometric CL in Iran and has been under consideration by WHO. This study investigated the environmental and geographic factors affecting the occurrence and distribution of CL in this focus.

Methods

Demographic data and the home addresses of CL patients diagnosed from 2015 to 2020 were retrieved from the Leishmaniasis Center of Bam in southeast Iran. The effects of mean annual rainfall (MAR), mean annual humidity (MAH), mean annual temperature (MAT), maximum annual temperature (MaxMAT), minimum annual temperature (MinMAT), mean annual humidity (MAH), mean annual evaporation (MAE), mean annual frosty days (MAFD), mean annual snowy hours (MASH), elevation, and land cover on the distribution of CL were analyzed using geographical information systems (GIS) and univariate and multivariate regression models.

Results

Of 847 patients studied, 50.9% (n = 431) were female and 49.1% (n = 416) were male. The age classes 0-10 (n = 246) and 11-20 (n = 145) showed the highest frequency of patients, respectively. Leishmaniasis patients were reported from 66 villages/cities (11.8%) out of 561 residential areas in Bam County. Univariate analysis showed that urban settings (OR = 21.66), agriculture (OR = 5.73), orchards (OR = 5), salty land (OR = 1.05), and temperatures (OR = 2.37, 2.79 and 3.47) had positive effects on CL occurrence (p < 0.05), while altitude, precipitation, humidity, evaporation, and the number of frozen days had negative effects. Multivariate analysis identified urban settings (OR = 13.6), orchards (OR = 6.29), agriculture (OR = 5.82), and minimum temperature (OR = 2.38) as the most significant determinants of CL occurrence in this region.

Conclusion

Environmental and ecological factors play an important role in the distribution of CL in Bam County. The high-risk zones for CL are cities/large villages, agricultural and orchard areas in lower altitudes and with warmer climates and lower rainfall and humidity. This model can guide researchers and health managers to properly conduct CL control programs and allocate budgets.

Tapeworms detected in wolf populations in Central Italy (Umbria and Marche regions): A long-term study

Tapeworms are trophically-transmitted and multi-host parasites with a complex indirect life cycle, strictly depending on predator-prey interactions. Their presence in a free-living population, mainly definitive hosts, is arduous to study due to the complexity of collecting fecal samples. However, epidemiological studies on their frequency are crucial from a public health perspective, providing information on food habits and prey selection of predators. The present study aims to update the frequency of tapeworms detected in stool samples by molecular analysis in Italian wolf populations of Umbria and Marche regions collected from 2014 to 2022. Tapeworm's total frequency was 43.2%. In detail, Taenia serialis was detected in 27 samples (21.6%), T. hydatigena in 22 (17.6%), and Mesocestoides corti (syn. M. vogae) in 2 (1.6%). Three samples were identified as M. litteratus and E. granulosus s.s. (G3) and T. pisiformis, with a proportion of 0.8%, respectively. The low frequency of E. granulosus in a hyperendemic area is discussed. The results show for the first time a high frequency of Taenia serialis not comparable to other Italian studies conducted on wild Carnivora; thus, a new ecological niche is conceivable. These findings suggest a plausible wolf-roe deer cycle for T. serialisin the investigated area.

Geo-climatic risk factors for chronic rhinosinusitis in southwest Iran

Chronic rhinosinusitis (CRS) is a prevalent and disabling paranasal sinus disease associated with some environmental factors. In this study, we evaluated the effect of geo-climatic factors on CRS in a region of southwest Iran. The study mapped the residency addresses of 232 patients with CRS who lived in Kohgiluyeh and Boyer-Ahmad province and had undergone sinus surgery from 2014 to 2019. The effects of Mean Annual Humidity (MAH), Mean Annual Rainfall (MAR), Mean Annual Temperature (MAT), maximum MAT (maxMAT), minimum MAT (minMAT), Mean Annual Evaporation (MAE), wind, elevation, slope, and land cover were assessed on the occurrence of CRS using Geographical Information System (GIS). Statistical analysis was performed using univariate and multivariate binary logistic regression. Patients came from 55 points including villages, towns, and cities. In univariate analysis, climatic factors including MAT (OR = 0.537), minMAT (OR = 0.764), maxMAT (OR = 0.63), MAR (OR = 0.994), and MAH (OR = 0.626) were significantly related to CRS occurrence. Elevation (OR = 0.999), slope (OR = 0.9), and urban setting (OR = 24.667) were the significant determinants among geographical factors when analyzed independently. The multivariate analysis found maxMAT (OR = 0.5), MAR (OR = 0.994), elevation (OR = 0.998), and urban (OR = 16.8) as significant factors affecting CRS occurrence. The urban setting is the most critical factor affecting CRS disease. Cold and dry areas and low attitude are the other risk factors for CRS in Kohgiluyeh and Boyer-Ahmad province, southwest Iran.

Serological surveillance of parasitic zoonoses in 13 highlands regions of Peru: Period 2016-2019

OBJECTIVES.

Motivation for the study. To understand the characteristics and distribution of the main parasitic zoonoses in Peru and to generate data for decision making in surveillance, prevention and control. Main findings. These parasitic zoonoses are distributed in areas of extreme poverty in the central and southern highlands of Peru. Fascioliasis seropositivity was found to be higher than for echinococcosis and cysticercosis. In addition, sociodemographic characteristics and lifestyle habits influence the transmission of these zoonoses. Implications. An active search for these zoonoses should be carried out in other risk areas with similar epidemiological characteristics to determine the prevalence of each of these zoonoses and implement multisectoral prevention and control programs. . To determine seropositivity to anti-IgG antibodies against Echinococcus granulosus, Fasciola hepatica and Taenia solium cysticercus infection and to describe the characteristics of the infected patients in 13 regions of the Peruvian highlands between 2016 and 2019.

MATERIALS AND METHODS.

Cross-sectional, observational study, in which we analyzed 7811 epidemiological records of laboratory-based surveillance of parasitic zoonoses from 2016 to 2019. Diagnosis was established by detecting IgG type anti-E. granulosus, F. hepatica and T. solium cysticercus antibodies using native antigens by enzyme-linked immunosorbent assay (ELISA) and Immunoblot. We evaluated the difference in the frequency of the cases according to identified characteristics using Pearson's chi-square test and Fisher's exact test.

RESULTS.

Seropositivity was 7.9% for fascioliasis, 4.9% for cystic echinococcosis, and 2.3% for T. solium cysticercus. These rates were higher in Cerro de Pasco for cystic echinococcosis (24.5%), in Ayacucho for T. solium cysticercus (4.5%) and in Puno for fascioliasis (40.6%). Regarding the sociodemographic characteristics, we found a statistically significant difference in the frequency of cases for all zoonoses according to age group, occupation, and region of residence. We also found a difference with the consumption of vegetables in emollients, and between clinical-epidemiological characteristics and having a family history of parasitic zoonoses.

CONCLUSIONS.

From the 7811 samples, we found that these parasitic zoonoses are distributed in 13 regions of the Peruvian highlands, and represent a major health problem, with frequencies that change according to different characteristics.

Seroprevalence of Anti-Echinococcus granulosus Antibodies and Risk Factors for Infection in Blood Donors from Western Romania

Cystic echinococcosis is a worldwide-distributed zoonotic parasitic disease. This cross-sectional study aimed to assess the seroprevalence and risk factors potentially associated with Echinococcus granulosus in healthy blood donors from Timis County, an endemic region in Western Romania. Serum samples were collected from 1347 Romanian blood donors. Serologic tests to determine the presence of anti-Echinococcus antibodies were performed using an anti-Echinococcus-ELISA immunoassay. Anti-Echinococcus antibodies were detected in 38 blood donors, indicating an overall seroprevalence of 2.8%. The seropositivity rate was 3.7% in females and 3.1% in blood donors residing in urban areas. The highest seropositivity was found in the age group of 31-40 years (3.6%). There were no significant differences between Echinococcus seropositivity and gender, area of residence, age, contact with dogs, or raising sheep. This serologic survey evaluated for the first time the presence of Echinococcus antibodies in healthy blood donors from Western Romania and the potential risk factors associated with echinococcosis. Our results suggest that this zoonotic infection might evolve asymptomatically in apparently healthy individuals. Further studies should be conducted in the general population to estimate the true extent of human echinococcosis and its risk factors.

Comparison of Isoenzyme Pattern of Echinococcus granulosus sensu stricto (G1-G3) and E. canadensis (G6/G7) Protoscoleces

Background

Different genotypes of Echinococcus granulosus sensu lato (s.l.) infect humans and ungulate animals, causing cystic echinococcosis. Simultaneous isoenzyme, as well as molecular characterizations of this parasite, has not yet been investigated in Iran. The present study aimed to evaluate the isoenzyme pattern of the E. granulosus sensu stricto (s.s.) and E. canadensis genotypes in Iran.

Methods

A total of 32 (8 humans and 24 animals) cystic echinococcosis cysts were isolated from Shiraz, Tehran, Ilam, and Birjand from May 2018 to December 2020. The DNAs were extracted and their genotypes were determined by molecular methods. Enzymes were extracted from the cysts and subjected to polyacrylamide gel electrophoresis. The activities of glucose-6-phosphate sehydrogenase (G6PD), malate dehydrogenase (MDH), malic enzyme (ME), nucleoside hydrolyse 1 (NH1), and isocitrate dehydrogenase (ICD) were examined in the cyst samples using isoenzyme method and compared it with the genotyping findings.

Results

DNA sequence analysis of the samples showed that the specimens contained 75% E. granulosus s.s. (G1) and 25% E. canadensis (G6) genotypes. The isoenzyme pattern of ICD in both genotypes produced a six-band pattern with different relative factors. The G6PD also produced two bands with different relative migrations in both genotypes. The MDH and NH1 systems revealed a two-band pattern, while only one band was generated in the ME enzyme in the E. granulosus s.s. genotype. In the E. canadensis, the MDH and NH1 enzymes showed one band, and the ME enzyme represented a two-band pattern.

Conclusion

Our findings suggest that E. granulosus s.s. and E. canadensis genotypes have entirely different isoenzyme patterns for NH1, G6PD, MDH, and ME.

Comparison of Isoenzyme Pattern of Echinococcus granulosus sensu stricto (G1-G3) and E. canadensis (G6/G7) Protoscoleces

Background

Different genotypes of Echinococcus granulosus sensu lato (s.l.) infect humans and ungulate animals, causing cystic echinococcosis. Simultaneous isoenzyme, as well as molecular characterizations of this parasite, has not yet been investigated in Iran. The present study aimed to evaluate the isoenzyme pattern of the E. granulosus sensu stricto (s.s.) and E. canadensis genotypes in Iran.

Methods

A total of 32 (8 humans and 24 animals) cystic echinococcosis cysts were isolated from Shiraz, Tehran, Ilam, and Birjand from May 2018 to December 2020. The DNAs were extracted and their genotypes were determined by molecular methods. Enzymes were extracted from the cysts and subjected to polyacrylamide gel electrophoresis. The activities of glucose-6-phosphate sehydrogenase (G6PD), malate dehydrogenase (MDH), malic enzyme (ME), nucleoside hydrolyse 1 (NH1), and isocitrate dehydrogenase (ICD) were examined in the cyst samples using isoenzyme method and compared it with the genotyping findings.

Results

DNA sequence analysis of the samples showed that the specimens contained 75% E. granulosus s.s. (G1) and 25% E. canadensis (G6) genotypes. The isoenzyme pattern of ICD in both genotypes produced a six-band pattern with different relative factors. The G6PD also produced two bands with different relative migrations in both genotypes. The MDH and NH1 systems revealed a two-band pattern, while only one band was generated in the ME enzyme in the E. granulosus s.s. genotype. In the E. canadensis, the MDH and NH1 enzymes showed one band, and the ME enzyme represented a two-band pattern.

Conclusion

Our findings suggest that E. granulosus s.s. and E. canadensis genotypes have entirely different isoenzyme patterns for NH1, G6PD, MDH, and ME.

How climate, landscape, and economic changes increase the exposure of Echinococcus Spp

BACKGROUND

Echinococcosis is a global enzootic disease influenced by different biological and environmental factors and causes a heavy financial burden on sick families and governments. Currently, government subsidies for the treatment of patients with echinococcosis are only a fixed number despite patients' finical income or cost of treatment, and health authorities are demanded to supply an annual summary of only endemic data. The risk to people in urban areas or non-endemic is increasing with climate, landscape, and lifestyle changes.

METHODS

We conducted retrospective descriptive research on inpatients with human echinococcosis (HE) in Lanzhou hospitals and analyzed the healthcare expenditure on inpatient treatment and examined the financial inequalities relating to different levels of gross domestic product. The livestock losses were also estimated by infection ratio. The occurrence records of Echinococcus spp. composed of hospitalized patients and dogs infected in the Gansu province were collected for Ecological niche modeling (ENM) to estimate the current suitable spatial distribution for the parasite in Gansu province. Then, we imported the resulting current niche model into future global Shared Socioeconomic Pathways scenarios for estimation of future suitable habitat areas.

RESULTS

Between 2000 to 2020, 625 hospitalized HE patients (51% men and 49% women) were identified, and 48.32 ± 15.62 years old. The average cost of hospitalization expenses per case of HE in Gansu Province was ￥24,370.2 with an increasing trend during the study period and was negative with different counties' corresponding gross domestic product (GDP). The trend of livestock losses was similar to the average cost of hospitalization expenses from 2015 to 2017. The three factors with the strongest correlation to echinococcosis infection probability were (1) global land cover (GLC, 56.6%), (2) annual precipitation (Bio12, 21.2%), and (3) mean temperature of the Wettest Quarter (Bio12, 8.5% of variations). We obtained a robust model that provides detail on the distribution of suitable areas for Echinococcus spp. including areas that have not been reported for the parasite. An increasing tendency was observed in the highly suitable areas of Echinococcus spp. indicating that environmental changes would affect the distributions.

CONCLUSION

This study may help in the development of policies for at-risk populations in geographically defined areas and monitor improvements in HE control strategies by allowing targeted allocation of resources, including spatial analyses of expenditure and the identification of non-endemic areas or risk for these parasites, and a better comprehension of the role of the environment in clarifying the transmission dynamics of Echinococcus spp. Raising healthcare workers' and travelers' disease awareness and preventive health habits is an urgent agenda. Due to unpredictable future land cover types, prediction of the future with only climatic variables involved needs to be treated cautiously.

Mathematical modelling of echinococcosis in human, dogs and sheep with intervention

In this study, a model for the spread of cyst echinococcosis with interventions is formulated. The disease-free and endemic equilibrium points of the model are calculated. The control reproduction number Rc for the model is derived, and the global dynamics are established by the values of Rc. The disease-free equilibrium is globally asymptotically stable if and only if Rc<1. For Rc>1, using Volterra-Lyapunov stable matrices, it is proven that the endemic equilibrium is globally asymptotically stable. Sensitivity analysis to identify the most influential parameters in the dynamics of CE is carried out. To establish the long-term behaviour of the disease, numerical simulations are performed. The impact of control strategies is investigated. It is shown that, whenever vaccination of sheep is carried out solely or in combination with cleaning or disinfecting of the environment, cyst echinococcosis can be wiped out.

Meta-analysis of the prevalence of bovine cystic echinococcosis in China during decade

BACKGROUND

Cystic echinococcosis (CE) is a zoonotic parasitic disease caused by Echinococcus granulosus sensu lato (E. granulosus s.l.) larvae. It is mainly prevalent in western agricultural and pastoral areas in China, seriously affecting the development of public health and animal husbandry.

METHODS

This study conducted a systematic evaluation and meta-analysis of bovine CE in China in the past 10 years (2011-2020). Five databases (PubMed, ScienceDirect, CNKI, Wanfang Data, VIP Chinese Journal Database) were used to collect the relevant references, and finally 77 published articles were obtained.

RESULTS

The total prevalence of bovine CE was estimated to be 9.62% during decade, and decreased year by year after reaching its peak in 2014 (18.75%). The highest E. granulosus s.l. infection rate was found in Qinghai province (14.79%). The infection rate of cattle >4 years old (15.84%) was significantly higher than that of other age groups, and cattle raised by grazing was significantly higher than that of other methods (17.00%). In the groups of geographical and climatic factors, the prevalence of CE was higher in regions with high-altitude (20.76%), cold (20.76%) and rainy areas (11.33%).

CONCLUSION

This study found that old age and grazing were two important factors for the high incidence of bovine CE. The prevalence of CE is higher in low temperature, rainy and high altitude areas, where may be more suitable for the survival of E. granulosus s.l. eggs.

Serosurvey of Cystic Echinococcosis and Related Risk Factors for Infection in Fars Province, Southern Iran: A Population-Based Study

Cystic echinococcosis (CE) is a common zoonotic infection in all provinces of Iran, especially in areas where people live on agriculture and animal husbandry. The current cross-sectional population-based study is aimed at determining the seroprevalence of CE in Kavar County, Fars province, southern Iran. Blood samples were collected from 1500 individuals (749 males and 751 females). Anti-hydatid cyst antibodies were detected, using a recombinant B8/1 antigen of Echinococcus graunlosus in an ELISA system. Multivariate logistic regression analysis was used to find out the independent risk factor for CE seropositivity. Anti-hydatid cyst antibodies were detected in the sera of 131 out of 1500 participants, corresponding to a seroprevalence rate of 8.73%. With a statistically significant difference ( $p<0.05$ ), the seroprevalence of hydatid cyst in males and females was 5% and 7%, respectively. Differences in the seropositivity of hydatid cysts were also statistically significant by occupation ( $p<0.05$ ). The seroprevalence of hydatid cyst was significantly higher in the age group of 35-45 years than in other age groups ( $p<0.05$ ). Multivariate logistic regression showed that only age was associated with seropositivity to CE ( $\text{OR}=2.23$ , 95% CI: 1.33-3.72). Moreover, there was a statistically significant association between seropositivity to hydatid cysts and underlying diseases such as hypertension ( $p=0.049$ ) and fatty liver ( $p=0.048$ ). The findings of this study indicate that the seroprevalence rate of CE is relatively high in the Fars province, southern Iran, and this high rate of infection is mainly linked to people’s jobs and lifestyles.

Global Prevalence of Echinococcosis in Goats: A Systematic Review and Meta-Analysis

Echinococcosis is a foodborne parasitic zoonosis caused by the larvae of Echinococcus. This disease can affect goats and other mammals. In this study, a systematic review and meta-analysis for echinococcosis in global goats were performed based on the following five databases (China National Knowledge Infrastructure [CNKI], VIP Chinese Journal Database, Wanfang Data, PubMed, and ScienceDirect). In total, 108,197 samples were collected. The global prevalence of echinococcosis in goats was identified to be 10.85% (3217/108,197). The prevalence of echinococcosis in goats was 6.16% (1369/22,208) and 13.27% (874/5932) in South America and Africa, respectively. The prevalence of echinococcosis in goats before 2010 (9.76%; 112/713) was significantly higher than that from 2010 to 2014 (1.44%; 45/32,145) or after 2014 (2.95%; 154/3889). The prevalence of echinococcosis in goats aged <12 months (4.48%; 70/2911) was higher than that in goats aged ≥12 months (2.88%; 36/819). We also investigated the effects of geographical factors and climates on the prevalence of echinococcosis in goats. The results showed that the prevalence of echinococcosis was higher in the areas with high altitude and cold climate. This meta-analysis indicated that echinococcosis was ubiquitous in goats. Thus, we should improve the feeding conditions for goats, and strengthen the control measures of echinococcosis epidemic in goats, with the aims of reducing the economic losses of animal husbandry and providing protection for humans in the aspects of food security and health.

Three cases of brain hydatidosis in North Khorasan, Iran

Cystic hydatidosis is a serious public health problem in Iran. Although cysts can develop in almost all organs and the brain cysts are very rare. Here, we present 3 confirmed cases of brain hydatidosis and the patients who underwent successful surgery. Pathological examinations demonstrated the presence of cystic hydatidosis.

Risk Mapping and Spatial Modeling of Human Cystic Echinococcosis in Iran from 2009 to 2018: A GIS-Based Survey

BACKGROUND

Cystic echinococcosis (CE) is one of the most important parasitic infections in subgroup seven common neglected diseases of humans and animals. It is in the list of 18 neglected tropical diseases of the WHO. We aimed to analyze the situation of the disease in Iran using Geographical Information System (GIS) and satellite data analysis.

METHODS

The data obtained from the Ministry of Health and Medical Education, Tehran, Iran and other related centers from 2009 to 2018 were analyzed using GIS. Then, the spatial distribution maps of the disease were generated, and the hot spots of the disease in Iran were determined using spatial analysis of ArcGIS10.5 software. Geographically weighted regression (GWR) analysis in ArcGIS10.5 was used to correlate the variables affecting the disease including temperature, relative humidity, normalized different vegetation index (NDVI) and incidence of hydatidosis. Data analysis was performed by Linear regression analysis and SPSS 21 software using descriptive statistics and chi-square test.

RESULTS

Zanjan, Khorasan Razavi, North Khorasan, Chaharmahal Bakhtiari, Hamedan, Semnan, and Ardabil provinces were the hot spots of CE. The results of geographical weighted regression analysis showed that in Khorasan Razavi, North Khorasan, Chaharmahal Bakhtiari, Hamedan, Semnan, Ardabil, Zanjan, Qazvin, and Ilam provinces, the highest correlation between temperature, humidity, vegetation density and the incidence of hydatidosis was observed (P<0.001).

CONCLUSION

The use of maps could provide reliable estimates of at-risk populations. Climatic factors of temperature, humidity, NDVI had a greater impact on the probability of hydatidosis. These factors can be an indicator used to predict the presence of disease. Environmental and climatic factors were associated with echinococcosis.

Assessment of the Vaccination Program against Cystic Echinococcosis in Sheep in the Pehuenche Community of Central Chile

Echinococcosis is a neglected zoonosis that uses dogs and sheep as its main hosts in Chile. The Eg95 vaccine against sheep infection has been included in some control programs. Here, we assess the efficacy of the vaccination program in the hyperendemic Alto Biobío commune after 3 years of execution. Fisher’s test and generalized linear models were used in the assessment. The program tried to offer a first dose at 2 months of age, a booster 1 month later, and yearly vaccination. Given logistic difficulties, important delays in vaccination occurred, and most animals did not receive the first booster. Dog deworming was not included in the program. Likely due to the aforementioned factors, the overall frequency of infection was not lower, but the proportion of large (>5 mm) cysts and fertile cysts was smaller after the program. The frequency of infection and/or the number of cysts were lower when the age at first dose was younger and the first booster was administered 1 month after the first dose. The results suggest that vaccination affects both cyst development after the larvae reach the target organs, as well as the development of the protoscolex once the cysts start developing.

Sequence analysis, intra-genotyping variation, and phylogenetic study of nad1 gene in Echinococcus granulosus sensu lato genotypes from intermediate hosts in southwestern Iran

Cystic echinococcosis (CE) is caused by the larval stage of Echinococcus granulosus sensu lato (s. l.). The disease is cosmopolitan, and Iran is a highly endemic area for CE. This parasite exhibits high genetic diversity, which can be related to its life cycle, transmission, and pathogenesis. This study was aimed at determining the phylogenetic relationship and intra-genotyping variation of E. granulosus s.l. in a vast area in the southwest of Iran (SWI). Eighty hydatid cyst isolates of intermediate hosts (i.e., cattle, sheep, goat, buffalo, camel, and human) were collected. The sequence analysis of the nad1 gene exhibited the three genotypes of G1 (n = 70, 87.5%), G3 (n = 8, 10%), and G6/G7 (n = 2, 2.5%). Also, 16, 2, and 1 unique haplotypes were identified for the G1, G3, and G6/G7 genotypes, respectively. According to the phylogenetic tree topology, the nad1 gene similarities were found for some G1 isolates in some vast areas, and the G1 genotype showed a heterogeneous population worldwide. The only SWI G6/G7 haplotype was at a distant position in E. canadensis clade, indicating the notable difference of this haplotype from other isolates from Iran and other countries. The presence of the G6/G7 genotype in the SWI may be due to the transmission of the genotype from other regions or the role of camel/wild boar or other possible hosts in the expansion of this genotype in SWI. The results of the present study can be used in CE control programs, molecular epidemiology, and phylogenetic studies in Iran and other countries for future goals.