An epidemiological comparative study on diagnosis of rodent leptospirosis in Mazandaran Province, northern Iran

Improvement the expression and purification of Loa22: a lipoprotein with OmpA domain from pathogenic Leptospira serovars

Background and Objectives

One of the highly conserved outer membrane proteins expressed only by pathogenic Leptospires is Loa22. The study aims is to achieve the optimum conditions for high expression of recombinant Loa22 (rLoa22) protein.

Materials and Methods

Complete coding sequence of loa22 gene sub-cloned into a pET32a (+) expression vector. BL21 competent E. coli (pLysS) used as expression host for transformation. The recombinant clones selected on ampicillin plates and subjected to PCR by using pET T7 primers. Then expression conditions optimized by adjusting parameters such as culture media, induction time, temperature, and IPTG concentration.

Results

SDS-PAGE analysis showed that high production of rLoa22 protein obtained when post induction incubation, IPTG concentration, and duration of induction were 37°C, 0.1 M and 5 h in 2×TY medium respectively. The purification of rLoa22 protein under native conditions using Ni-NTA pull-down was optimum in one hour binding at 37°C, five times washing process and elution buffer with a pH 7.4 and a 0.3 M imidazole concentration.

Conclusion

The findings of the study led to high production of pure Loa22 protein, which can form the basis for future investigation on the design of rapid diagnostic tests and more effective vaccine candidates for leptospirosis.

Clinico Epidemiological Study of Human Leptospirosis in Hilly Area of South India-A Population Based Case Control Study

Background

Leptospirosis is the most common zoonotic disease in the world affecting both animals and humans. Environmental, occupational, and sociocultural practices which vary from region to region favors the disease transmission in addition to lacunas in prompt diagnosis and treatment of cases. There are limited data on the seroprevalence of this neglected tropical disease in India. To assess the risk factors associated with Lepospirosis disease.

Materials and Methods

A population-based case control study was conducted in Kodagu district of southern India from January 2022 to March 2022. Of the 74 confirmed cases during the year 2021, 70 cases and 140 age group and gender-matched controls participated in the study. Data were collected by using semi-structured questionnaire containing details of sociodemographic, occupational, and environmental factors. The collected data were coded and exported to STATA (16.1) and analyzed by univariate and multivaiariate logistic regression to identify significant risk factors.

Results

Environmental factors such as flooding or collection of water near the house (adjusted Odds Ratio [aOR] = 4.9, confidence interval [CI]: 1.4-17.0), proximity to an open sewer (aOR = 4.9, CI: 1.2-19.1) and occupational factors such as presence of skin cuts or abrasion during work (aOR = 4, CI: 1.4-11.6), direct contact with mud or water during work (aOR = 9.7, CI: 3.3-27.7), animal farming (aOR = 3.4, CI: 1.0-11.6), presence of rodents in the house (aOR = 4, CI: 1.2-12.6), and presence of rodent habitats like grain storage area (aOR = 3.5, CI: 1.1-11.0) were significantly associated with leptospirosis.

Conclusion

Leptospirosis poses a potential public health problem in the district. Interventions like prompt diagnosis and treatment, sensitization programs, and rodent control measures will significantly control this neglected tropical disease.

Seroepidemiology of leptospirosis in livestock and workers of high-risk occupation in Kurdistan, Iran

BACKGROUND

Leptospirosis is one of the major zoonotic infectious diseases which could cause disease in both animals and humans. Using ELISA is one of the serological tests that could be used in the detection of leptospirosis. Based on the different reports about the prevalence of leptospirosis in different parts of our country, we aimed to investigate the rate of Leptospira spp, among livestock and human in Kurdistan province.

MATERIAL AND METHOD

ELISA assay was performed by ELISA kit (Novatec, Germany) for quantitative detection of anti-Leptospira IgG in human and IgM antibody and total antibodies (IgM and IgG) in serum samples of livestock.

RESULTS

In the present study, the seroprevalence in sheep, goats, and cows was (2/30) 6.7% [95% CI 0.8%,22.1%], (1/31) 3.2% [ 95% CI 0.08%,16.7%] and 0%, respectively. Also, the rate of anti-Leptospira was (1/51) 1.9% [95% CI 0.05%,10.4%] among 51 human participants.

DISCUSSION

the current study, provided some valuable information on the rate of leptospirosis in animal and human participants from west of Iran, which can be useful in terms of monitoring the disease in the area and helping the health care system to control the roots of bacterial transmission.

Impacts of flood on health of Iranian population: Infectious diseases with an emphasis on parasitic infections

Background

Outbreaks of infectious diseases are the major concern after flooding. Flood makes people displacement which would be more complicated with inadequate sanitation. Settling in crowded shelters in absence of clean water and inaccessibility to health care services makes people more vulnerable to get infection. This review aimed to discuss about potential undesirable outcomes of flooding occurred in 2019 in Iran.

Methods

A comprehensive search was carried out in databases including PubMed, Google scholar, Scopus, Science Direct, Iran medex, Magiran and SID (Scientific information database) from 2000 to 2019. All original descriptive articles on flood were concerned. Related articles on flood disturbance were considered. Also, publication of red cross society was considered as only reliable reference in evaluation of consequences of flood occurred in 2019 in Iran.

Results

Flooding in Iran, was started in March 2019 and lasted to April 2019. Flood affected 31 provinces and 140 rivers burst their banks, and southwestern Iran being hit most severely. According the reports of international federation of red cross society, 3800 cities and villages were affected by the floods with 65,000 destroyed houses and 114,000 houses partially damaged. Also 70 hospitals or health care centers with 1200 schools were damaged along with many infrastructures including 159 main roads and 700 bridges.

Conclusions

Considering 365,000 displaced persons and estimation of mentioned damages, it was one of the greatest natural disaster during the last 20 years. Various risk factors in favor of infectious diseases such as overcrowding, disruption of sewage disposal, poor standards of hygiene, poor nutrition, negligible sanitation and human contact among refugees provide suitable conditions for increased incidence of infectious diseases after flooding and also cause epidemics.More attention is needed to provide hygienic situation for people after natural disasters including flood.

Leptospirosis: Increasing importance in developing countries

Leptospirosis is a zoonotic disease caused by the pathogenic helical spirochetes, Leptospira. Symptoms include sudden-onset fever, severe headaches, muscle pain, nausea and chills. Leptospirosis is endemic in developing countries such as Malaysia, India, Sri Lanka, and Brazil where thousands of cases are reported annually. The disease risk factors include the high population of reservoirs, environmental factors, recreational factors, and occupational factors. To end the endemicity of leptospirosis, these factors need to be tackled. The management of leptospirosis needs to be refined. Early diagnosis remains a challenge due to a lack of clinical suspicion among physicians, its non-specific symptoms and a limited availability of rapid point-of-care diagnostic tests. The purpose of this review is to provide insight into the status of leptospirosis in developing countries focusing on the risk factors and to propose methods for the improved management of the disease.

Leptospira infection in rats: A literature review of global prevalence and distribution

Background

The role of rodents in Leptospira epidemiology and transmission is well known worldwide. Rats are known to carry different pathogenic serovars of Leptospira spp. capable of causing disease in humans and animals. Wild rats (Rattus spp.), especially the Norway/brown rat (Rattus norvegicus) and the black rat (R. rattus), are the most important sources of Leptospira infection, as they are abundant in urban and peridomestic environments. In this study, we compiled and summarized available data in the literature on global prevalence of Leptospira exposure and infection in rats, as well as compared the global distribution of Leptospira spp. in rats with respect to prevalence, geographic location, method of detection, diversity of serogroups/serovars, and species of rat.

Methods

We conducted a thorough literature search using PubMed without restrictions on publication date as well as Google Scholar to manually search for other relevant articles. Abstracts were included if they described data pertaining to Leptospira spp. in rats (Rattus spp.) from any geographic region around the world, including reviews. The data extracted from the articles selected included the author(s), year of publication, geographic location, method(s) of detection used, species of rat(s), sample size, prevalence of Leptospira spp. (overall and within each rat species), and information on species, serogroups, and/or serovars of Leptospira spp. detected.

Findings

A thorough search on PubMed retrieved 303 titles. After screening the articles for duplicates and inclusion/exclusion criteria, as well as manual inclusion of relevant articles, 145 articles were included in this review. Leptospira prevalence in rats varied considerably based on geographic location, with some reporting zero prevalence in countries such as Madagascar, Tanzania, and the Faroe Islands, and others reporting as high as >80% prevalence in studies done in Brazil, India, and the Philippines. The top five countries that were reported based on number of articles include India (n = 13), Malaysia (n = 9), Brazil (n = 8), Thailand (n = 7), and France (n = 6). Methods of detecting or isolating Leptospira spp. also varied among studies. Studies among different Rattus species reported a higher Leptospira prevalence in R. norvegicus. The serovar Icterohaemorrhagiae was the most prevalent serovar reported in Rattus spp. worldwide. Additionally, this literature review provided evidence for Leptospira infection in laboratory rodent colonies within controlled environments, implicating the zoonotic potential to laboratory animal caretakers.

Conclusions

Reports on global distribution of Leptospira infection in rats varies widely, with considerably high prevalence reported in many countries. This literature review emphasizes the need for enhanced surveillance programs using standardized methods for assessing Leptospira exposure or infection in rats. This review also demonstrated several weaknesses to the current methods of reporting the prevalence of Leptospira spp. in rats worldwide. As such, this necessitates a call for standardized protocols for the testing and reporting of such studies, especially pertaining to the diagnostic methods used. A deeper understanding of the ecology and epidemiology of Leptospira spp. in rats in urban environments is warranted. It is also pertinent for rat control programs to be proposed in conjunction with increased efforts for public awareness and education regarding leptospirosis transmission and prevention.

The role of rodents in the transmission of many diseases, including leptospirosis, is widely known. Rats abundant in urban and peridomestic environments are the most important reservoirs and sources of Leptospira infection in humans and animals. Leptospirosis is a significant but neglected disease of humans and animals that is increasing in incidence in regions affected by natural disasters. This paper summarizes the global prevalence and distribution of Leptospira infection in rats and will add to the literature that supports research, education, and public awareness regarding leptospirosis transmission and prevention.

Investigation of Risk Factors Associated with Leptospirosis in the North of Iran (2011-2017)

BACKGROUND

The risk factors for infection with leptospirosis in Iran have never been studied. We aimed to determine the risk factors of leptospirosis and the epidemiological pattern of this disease in Golestan Province, Iran during 2011-2017.

STUDY DESIGN

A case-control study.

METHODS

This case-control study was performed on the population of patients diagnosed with leptospirosis. Controls were selected from the residents of Golestan province, northern Iran and were matched with the cases for gender, age group, and place of residence. After coding the data collected in checklists, the analysis was performed in SPSS using independent t-test, logistic regression, contingency tables, and Fisher exact test.

RESULTS

Eighty-seven cases were diagnosed infected with leptospirosis. Most patients were male (69.0%) and residents of rural areas (82.7%). The three leading risk factors for leptospirosis were exposure to stagnant rice paddy water while having a skin scratch/injury (OR=11.21, 95% CI: 3.02, 43.06), washing the face with stagnant rice paddy water (OR=11.33, 95% CI: 5.12, 25.01), and sighting of rats or rat nest in rice paddies (OR=3.30, 95% CI: 1.01, 11.62).

CONCLUSION

For farmers working in stagnant and muddy waters of rice paddies, occupational protection measures such as wearing waterproof boots, gloves, support, and socks can reduce the chance of infection with leptospirosis. Health education of the people with susceptible occupations about the transmission and prevention methods can also play a key role in controlling this disease.

Faunistic Study of the Rodents of North Khorasan Province, North East of Iran, 2011-2013

BACKGROUND

Rodents are one of the most important hosts for some zoonotic diseases and also act as a reservoir of some ectoparasites and endoparasites. They cause damage to the farms and inflict public health. The aim of this study was to investigate the faunal composition of rodent in North Khorasan Province, Northeast of Iran.

METHODS

The sampling was carried out between 2011 to 2013. The specimens were collected using different methods including rodent death and live traps, digging of their burrow, and hand net from 75 different sample sites.

RESULTS

The total number of 396 specimens belonging to 22 species and six families were identified. The results illustrated the high numbers and densities of Meriones persicus (17.68%), Meriones libycus (15.15%), Nesokia indica (7.32%) and Rhombomys opimus (6.82%), as the most important reservoirs for different zoonotic diseases. Moreover, significant number of other rodent species including Mus musculus (15.66%), Apodemus witherbyi (13.89%), A. hyrcanicus (0.25%), Rattus norvegicus (1.01%), Meriones crassus (0.25%), Gerbillus nanus (0.51%), Microtus paradoxus (2.27%), M. transcaspicus (0.76%), Ellobius fuscocapillus (0.25%), Cricetulus migratorius (4.29%), Calomyscus elburzensis (4.29%), C. mystax (1.26%), Spermophilus fulvus (0.25%), Dryomys nitedula (3.54%), Allactaga elater (3.54%), Jaculus blanfordi (0.25%), Meriones zarudnyi (0.25%), M. meridianus (0.51%), and Hystrix indica as hosts for parasites and zoonotic diseases were identified.

CONCLUSION

The high biodiversity including at least 22 species and six families of rodents were found in North Khorasan Province, some of them were medically important species.

Rodent-borne diseases and their public health importance in Iran

Background

Rodents are reservoirs and hosts for several zoonotic diseases such as plague, leptospirosis, and leishmaniasis. Rapid development of industry and agriculture, as well as climate change throughout the globe, has led to change or increase in occurrence of rodent-borne diseases. Considering the distribution of rodents throughout Iran, the aim of this review is to assess the risk of rodent-borne diseases in Iran.

Methodology/Principal finding

We searched Google Scholar, PubMed, Science Direct, Scientific Information Database (SID), and Magiran databases up to September 2016 to obtain articles reporting occurrence of rodent-borne diseases in Iran and extract information from them. Out of 70 known rodent-borne diseases, 34 were reported in Iran: 17 (50%) parasitic diseases, 13 (38%) bacterial diseases, and 4 (12%) viral diseases. Twenty-one out of 34 diseases were reported from both humans and rodents. Among the diseases reported in the rodents of Iran, plague, leishmaniasis, and hymenolepiasis were the most frequent. The most infected rodents were Rattus norvegicus (16 diseases), Mus musculus (14 diseases), Rattus rattus (13 diseases), Meriones persicus (7 diseases), Apodemus spp. (5 diseases), Tatera indica (4 diseases), Meriones libycus (3 diseases), Rhombomys opimus (3 diseases), Cricetulus migratorius (3 diseases), and Nesokia indica (2 diseases).

Conclusions/Significance

The results of this review indicate the importance of rodent-borne diseases in Iran. Considering notable diversity of rodents and their extensive distribution throughout the country, it is crucial to pay more attention to their role in spreading infectious diseases for better control of the diseases.

This review showed that approximately half of the known rodent-borne diseases have been reported in Iran, half of which were reported both in humans and rodents. Most of the diseases were bacterial and parasitic. Plague, leishmaniasis, and hymenolepiasis were the most frequent diseases among rodent populations. Also, this review showed that among the rodent species, three commensal ones—R. norvegicus, M. musculus, and R. rattus—play an important role in the transmission of diseases to humans in Iran. Considering repeated reports of many of these diseases in humans and rodents, and the notable diversity and extensive distribution of rodents throughout Iran, it is crucial to pay adequate attention to rodents as a source of zoonotic infectious diseases in the country.

Epidemiological Distribution of Rodents as Potent Reservoirs for Infectious Diseases in the Provinces of Mazandaran, Gilan and Golestan, Northern Iran

Rodents are mammals that comprise more than 2000 species and approximately 30 families. There are many morphological and ecological differences among them as variations in their shape, size, weight and habitat. In addition to significant economic losses, rodents have a major role in the dissemination of infectious diseases caused by viruses, bacteria, parasites or other micro-organisms. Rodents are important reservoirs of diseases which have been observed in many cities of Iran provinces especially along Caspian Sea border to Alborz Mountain. The aim of this study is to assess the geographical distribution of rodents in three provinces of northern part of Iran as reservoir of potential endemic infectious diseases. Rodents in 10 major parts of each of the three provinces of Mazandaran, Gilan and Golestan, northern Iran were collected and a total of 404 rodents were trapped alive. They were determined by the key characteristics such as gender, genus, species, different locations and topological situation. Statistical analysis was performed to characterize the study sample and to correlate all variables and parameters. The distribution frequencies of three, five and six genera of rodents were identified in Mazandaran, Gilan and Golestan provinces respectively. The overall distribution frequency of eight genera of rodents in the three provinces were identified as Rattus (R.) norvegicus (67.3%), R. rattus (13.6%), Apodemus sylvaticus (13.9%), Arvicola (1%), Mus musculus (0.3%), Nesokia indica (2.5%), Cricetulus migrates (0.7%) and Rhombomys opimus (0.7%). The results of this study determined the geographic distribution of the rodents in the three northern provinces of Iran. It is indicated the association of various distribution and diversity of rodents with provincial location. The overall distribution frequency of eight genera of rodents was recognized in the above three provinces geographical locations. This study confirms epidemiological distribution of various rodents as potent reservoirs for infectious diseases, such as leptospirosis, salmonellosis, tularemia, leishmaniasis, etc. in the three provinces.