Incidence Of Shigellosis Research Articles

Twenty-five years of sentinel laboratory-based surveillance of shigellosis in a high-income country endemic for the disease, Israel, 1998 to 2022.

BackgroundShigella is a leading cause of moderate-to-severe diarrhoea worldwide and diarrhoeal deaths in children in low- and-middle-income countries.AimWe investigated trends and characteristics of shigellosis and antimicrobial resistance of Shigella sonnei in Israel.MethodsWe analysed data generated by the Sentinel Laboratory-Based Surveillance Network for Enteric Pathogens that systematically collects data on detection of Shigella at sentinel laboratories, along with the characterisation of the isolates at the Shigella National Reference Laboratory. Trends in the shigellosis incidence were assessed using Joinpoint regression and interrupted time-series analyses.ResultsThe average incidence of culture-confirmed shigellosis in Israel declined from 114 per 100,000 population (95% confidence interval (CI): 112-115) 1998-2004 to 80 per 100,000 population (95% CI: 79-82) 2005-2011. This rate remained stable 2012-2019, being 18-32 times higher than that reported from the United States or European high-income countries. After decreasing to its lowest values during the COVID-19 pandemic years (19/100,000 in 2020 and 5/100,000 in 2021), the incidence of culture-confirmed shigellosis increased to 39 per 100,000 population in 2022. Shigella sonnei is the most common serogroup, responsible for a cyclic occurrence of propagated epidemics, and the proportion of Shigella flexneri has decreased. Simultaneous resistance of S. sonnei to ceftriaxone, ampicillin and sulphamethoxazole-trimethoprim increased from 8.5% (34/402) in 2020 to 92.0% (801/876) in 2022.ConclusionsThese findings reinforce the need for continuous laboratory-based surveillance and inform the primary and secondary prevention strategies for shigellosis in Israel and other endemic high-income countries or communities.

IgG Serum Antibodies to Shigella sonnei Lipopolysaccharide Are Inversely Associated with the Incidence of Culture-Proven S. sonnei Shigellosis in Israeli Children and Adolescents.

Shigella is a leading cause of moderate-to-severe diarrhea globally, with young children most affected. The burden of shigellosis drops increasingly with age, inferring the acquisition of natural immunity. We tested the hypothesis that IgG antibodies elicited against Shigella O-specific polysaccharide (O-SP) are correlates of age-acquired immunity. We examined levels and determinants of serum IgG to S. sonnei LPS and the association with the incidence of S. sonnei shigellosis in Israeli children and adolescents. We analyzed 1096 serum samples from 0- to 19-year-olds collected in 2008-2015 for IgG anti-S. sonnei LPS levels by ELISA. Corresponding age-specific incidences of culture-proven S. sonnei shigellosis from 2008 to 2015 were obtained. We compared ecologically IgG levels, prevalence above a proposed protective threshold, and S. sonnei shigellosis incidence. In a multivariable analysis model, children aged 1-4, 5-14, and 15-19 years were 6.71, 27.68, and 48.62 times more likely to have IgG anti-S. sonnei LPS above the threshold than those aged < 1 year, respectively (p < 0.001). Infants 0-3 months old had relatively high IgG anti-S. sonnei LPS levels of maternal origin that dropped thereafter. Children of low socioeconomic status had a 2.73 times higher likelihood of having IgG anti-S. sonnei LPS above the threshold (p < 0.001). A significant inverse correlation between age-specific IgG anti-S. sonnei LPS levels and S. sonnei shigellosis incidence was observed (Spearman rho= -0.76, p = 0.028). The study results support anti-S. sonnei LPS antibodies as correlates of protection that can inform Shigella vaccine development.

Genomic surveillance for comprehensive Shigella management

In The Lancet Infectious Diseases, Giannoula S Tansarli and colleagues 1 Tansarli GS Long DR Waalkes A et al. Genomic reconstruction and directed interventions in a multidrug-resistant Shigellosis outbreak in Seattle, WA, USA: a genomic surveillance study. Lancet Infect Dis. 2023; (published online Jan 30.)https://doi.org/10.1016/S1473-3099(22)00879-9 Google Scholar have reported their whole-genome sequencing (WGS)-based analyses of sustained shigellosis in Seattle, WA, USA, and have revealed the contemporaneous emergence of Shigella sonnei and Shigella flexneri, likely introduced from abroad. Interestingly, of the 171 isolates identified in patients, the investigators show a predominance of S flexneri (112 [66%]) over S sonnei (55 [32%]) and cite similar observations from Australia and the UK. Historically, S sonnei has been predominant in high-income countries (HICs), particularly among men who have sex with men (MSM) whereas S flexneri predominates in low-income to middle-income countries (LMICs), where children are disproportionately affected. In parallel, of the 171 patients, Tansarli and colleagues reported that 78 (46%) patients were MSM, and 88 (52%) were people experiencing homelessness (PEH) and accentuated the incidence of shigellosis among PEH in HICs. Genomic reconstruction and directed interventions in a multidrug-resistant Shigellosis outbreak in Seattle, WA, USA: a genomic surveillance studyAn outbreak in Seattle was driven by parallel emergence of multidrug-resistant strains involving international transmission networks and domestic transmission between at-risk populations. Genomic analysis elucidated not only outbreak origin, but directed optimal approaches to testing, treatment, and public health response. Rapid diagnostics combined with detailed knowledge of local epidemiology can enable high rates of appropriate empirical therapy even in multidrug-resistant infection. Full-Text PDF

Shigellosis in Poland in 2018-2019.

The purpose of this study is evaluation of the epidemiological situation of shigellosis in Poland in years 2018-2019, comparing to previous years. The evaluation of epidemiological situation of shigellosis in Poland was based on analysis of data from epidemiological surveillance collected in questionnaires and sent to the Department of Epidemiology of Infectious Diseases and Surveillance NIPH NIH-NRI by sanitary stations. Once a case was reported on a ZLK-1 and/or ZLB-1 form to the appropriate State Sanitary Inspector, an epidemiological investigation was conducted by collecting additional information from medical records and from the patient interview. Data from the "Infectious Diseases and Poisonings" bulletins years 2012-2019 was also used as well as data from shigellosis outbreaks acquired through ROE system - registry created for outbreak data gathering. In Poland in years 2018-2019 a total of 321 cases of shigellosis was reported. Incidence per 100,000 was 0.74 in 2018, which was considerably more than in previous years, and in 2019 was 0.10 - similarly as two years before. The most cases belonged to the 25-34 and 35-44 age groups, and the least cases to the 0-4 age group. Majority of them were women. Percentage of hospitalizations was 27% in described period. Regarding to previous years, in 2018 decrease of hospitalizations was noted. Imported cases were 54.8% of all with predominance of imports from Albania. Twenty eight percent of infections were caused by S. sonnei species. In discussed years 10 outbreaks were registered with 246 people ill, including two large outbreaks (77 and 150 cases). August was the month with the highest number of cases (217 cases, 67.6% of all), 62.2% of them were imported. Increase in number of cases and incidence of shigellosis in Poland in 2018 was caused by occurrence of two large epidemic outbreaks. Because of high percentage of imported cases, traveling to shigellosis endemic countries is currently the main risk factor for contracting the disease. This indicates the need for education for those who travel to endemic areas.

Changing epidemiology of shigellosis in Taiwan, 2010-2019: an emerging threat to HIV-infected patients and men who have sex with men

ABSTRACT Shigellosis appears to increase in certain at-risk populations in developed countries. Based on the nationwide surveillance, the annual incidence of shigellosis in Taiwan (1999-2019) was 0.38-5.77 cases per 100,000 people. Indigenous shigellosis has mostly affected men who have sex with men (MSM) and people living with HIV (PLWH) since 2015. In this retrospective study, compared with those diagnosed before 2015, indigenous cases diagnosed during 2015–2019 mostly occurred in male adults (96.0% vs 47.1%, P < 0.001), with a longer hospital stay (median 5.0 vs 3.5 days, P = 0.029) and different coinfections. The predominant strains in 2015 and 2016 were ciprofloxacin-resistant Shigella sonnei and azithromycin non-susceptible Shigella flexneri (S. flexneri) 3a, which had been replaced by ciprofloxacin-resistant S. flexneri 2a since 2018. Notably, six indigenous cases were caused by cefotaxime-resistant S. flexneri. Inappropriate use of empiric antibiotic treatment was common. In conclusion, there is an ongoing spread of ciprofloxacin-resistant shigellosis among PLWH and MSM and cefotaxime-resistant S. flexneri is an emerging threat in Taiwan.

A Significant Decrease in the Incidence of Shigellosis in Israel during COVID-19 Pandemic.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes COVID-19 and is mostly person-to-person transmitted through respiratory droplets. The implications of the strategies implemented to prevent COVID-19 transmission on other infectious diseases are unclear. We aimed to appraise trends in the incidence of salmonellosis, shigellosis and campylobacteriosis in Israel during COVID-19 pandemic. Positive stool samples for Salmonella, Shigella and Campylobacter are reported on a monthly basis to the Israel Center for Disease Control from sentinel laboratories, within the framework of a surveillance network of bacterial culture-proven enteric diseases. Age-adjusted incidence rates per 100,000 of shigellosis, salmonellosis and campylobacteriosis were calculated. Mean rates before and after the local onset of COVID-19 pandemic in Israel were compared and Relative Risk Reduction (RRR) was calculated. Joinpoint was used to evaluate secular trends. The mean age-adjusted incidence rate of shigellosis in March–July 2020 was lower than the rate observed in March–July 2018–2019 (RRR = 86.6%), but also decreased for salmonellosis (RRR = 33.0%) and campylobacteriosis (RRR = 30.0%). Using Joinpoint we have shown that the decrease observed for shigellosis was significantly sharper (Annual Percent Change (APC) = −77.7) between February 2020 and May 2020 than for salmonellosis (APC = −14.0) between July 2019 and April 2020 and for campylobacteriosis (APC = −1.1) between January 2018 and July 2020. The preventive measures applied to reduce transmission of COVID-19, including social distancing and hand washing, were ecologically associated with a decreased risk of bacterial enteric diseases in Israel. The association was strongest for shigellosis, a disease that is mostly person-to-person transmitted, as compared to salmonellosis and campylobacteriosis which are mostly foodborne transmitted.

Features of the Incidence of Shigellosis in the Karachay-Cherkess Republic in 2005–2019

Introduction: In the Karachay-Cherkess Republic (KCR), dysentery and salmonellosis rank high in the etiological structure of intestinal infections and arose interest in studying the incidence of shigellosis in the republic. Our objective was to analyze the incidence of bacillary dysentery, to study Shigella landscape in the territory of the KCR in 2005–2019, and to compare the findings with similar variables in other regions of the Russian Federation. Materials and methods: We analyzed data of the Center for Hygiene and Epidemiology in the Karachay-Cherkess Republic on the incidence of shigellosis and Shigella isolates obtained from human stool samples in the KCR in 2005–2019 and compared them with available results of similar studies conducted in other parts of the country. Results: When analyzing the curves of the incidence of dysentery in the KCR and the Russian Federation, we found that they were asynchronous. In the KCR, the curve rose twice (in 2005–2006 and 2011–2014), while in the Russian Federation, the incidence rates demonstrated a gradual decrease. Over the whole observation period, only in 2018–2019 the incidence of shigellosis in Karachay-Cherkessia was 1.3–1.8 times lower than in the country as a whole. We also established that, in contrast to the Russian Federation, Shigella sonnei represented by the biochemical variant IIg prevailed in the structure of shigellosis in the republic. The analysis of the relationship between the number of detected samples of dairy products of poor microbial quality and the incidence rate of Sonne dysentery showed that those two variables did not always correlate. Molecular genotyping of Shigella sonnei strains by pulsed-field gel electrophoresis (PFGE) allowed us to assume the imported nature of the pathogen. The import could have occurred during the Hajj to Mecca and Medina of KCR residents in 2012. Conclusion: Shigella sonnei strains differing in the presence of tetracycline and chloramphenicol (levomycetin) resistance determinants are circulating in Karachay-Cherkessia. No bacteria resistant to ciprofloxacin were isolated in the republic in 2005–2019.

Effects of El Niño/La Niña on the Number of Imported Shigellosis Cases in the Republic of Korea, 2004-2017.

Shigellosis is a major diarrheal disease in low- and middle-income countries. Although the incidence of such diseases in South and Southeast Asia has been associated with climate fluctuations linked to the El Niño–Southern Oscillation (ENSO), the impact of ENSO on shigellosis infections remains unknown. Data reported to being infected with shigellosis while traveling abroad from 2004 to 2017 were obtained from the Korea Centers for Disease Control and Prevention. We investigated the relationship between the Oceanic Niño Index (ONI) and Indian Ocean Dipole Mode Index and the relative risk of shigellosis in outbound travelers using distributed lag linear and non-linear models. From 2004 to 2017, 87.1% of imported shigellosis was infected in South and Southeast Asian countries. The relative risk of imported shigellosis infection in outbound travelers increased as the ONI decreased. In the association with the five-month cumulative ONI, the relative risk of infection continuously increased as the La Niña index gained strength. Climate fluctuations associated with the La Niña phenomenon in South and Southeast Asian countries can lead to issues in sanitation and water safety. Our findings suggest that the decreasing trend in the ONI is associated with an increased incidence of shigellosis in these countries.

Feasibility of containing shigellosis in Hubei Province, China: a modelling study

BackgroundThe transmission features and the feasibility of containing shigellosis remain unclear among a population-based study in China.MethodsA population–based Susceptible – Exposed – Infectious / Asymptomatic – Recovered (SEIAR) model was built including decreasing the infectious period (DIP) or isolation of shigellosis cases. We analyzed the distribution of the reported shigellosis cases in Hubei Province, China from January 2005 to December 2017, and divided the time series into several stages according to the heterogeneity of reported incidence during the period. In each stage, an epidemic season was selected for the modelling and assessing the effectiveness of DIP and case isolation.ResultsA total of 130,770 shigellosis cases were reported in Hubei Province. The median of Reff was 1.13 (range: 0.86–1.21), 1.10 (range: 0.91–1.13), 1.09 (range: 0.92–1.92), and 1.03 (range: 0.94–1.22) in 2005–2006 season, 2010–2011 season, 2013–2014 season, and 2016–2017 season, respectively. The reported incidence decreased significantly (trend χ2 = 8260.41, P < 0.001) among four stages. The incidence of shigellosis decreased sharply when DIP implemented in three scenarios (γ = 0.1, 0.1429, 0.3333) and when proportion of case isolation increased.ConclusionsYear heterogeneity of reported shigellosis incidence exists in Hubei Province. It is feasible to contain the transmission by implementing DIP and case isolation.

Sex differences in shigellosis incidence rates: analysis of national data from nine countries using meta-analytic method.

Sex differences in the incidence of infectious diseases can provide insight to the biological mechanism of infection, disease susceptibility, severity and vaccine development. The consistency of age-specific sex differences in the incidence rates (IRs) of shigellosis is unclear. National data on cases of shigellosis by sex, age group and calendar year were obtained from nine countries, for a period of 6-25 years. The male to female incidence rate ratios (RR) were calculated by country, years and age group. For each age group, meta-analytic methods were used for computing pooled incidence RRs by country and years. Meta-regression was performed to estimate the contribution of age, country and time period to the differences in the male : female RRs. In the age groups <1, 1-4, 5-9 and 10-14, there were excess IRs in males. The pooled incidence RRs (with 95% CI) were 1.21 (1.14-1.28), 1.17 (1.12-1.22), 1.04 (1.00-1.09) and 1.09 (1.01-1.18), respectively. In young adults, there was excess IR in females with RR = 0.80 (0.72-0.9). In middle aged and older adults, there was a slight excess in males with RR = 1.01 (0.89-1.15) and RR = 1.18 (1.09-1.28), respectively. In the meta-regression, age was the only variable that significantly contributed to the variation in the RRs. The higher IRs in male infants and young children does not appear to be related to behavioral factors and genetic and hormonal factors could be important. In the older age groups, the higher rates in adult females may be due to behavioral factors.

Epidemiological characteristics and transmissibility of shigellosis in Hubei Province, China, 2005 \u2013 2017

BackgroundShigellosis is one of the main diarrhea diseases in developing countries. However, the transmissibility of shigellosis remains unclear.MethodsWe used the dataset of shigellosis cases reported between January 2005 and December 2017, from Hubei Province, China. A mathematical model was developed based on the natural history and the transmission mechanism of the disease. By fitting the data using the model, transmission relative rate from person to person (b) and from reservoir to person (bw), and the effective reproduction number (Reff) were estimated. To simulate the contribution of b and bw during the transmission, we performed a “knock-out” simulation in four scenarios: A) b = 0 and bw = 0; B) b = 0; C) bw = 0; D) control (no intervention).ResultsA total of 130,770 shigellosis cases were reported in Hubei province, among which 13 cases were dead. The median annual incidence was 19.96 per 100,000 persons (range: 5.99 per 100,000 persons – 29.47 per 100,000 persons) with a decreased trend (trend χ2 = 25,470.27, P < 0.001). The mean values of b and bw were 0.0898 (95% confidence interval [CI]: 0.0851–0.0946) and 1.1264 × 10− 9 (95% CI: 4.1123 × 10− 10–1.8416 × 10− 9), respectively. The “knock-out” simulation showed that the number of cases simulated by scenario A was almost the same as scenario B, and scenario C was almost the same as scenario D. The mean value of Reff of shigellosis was 1.19 (95% CI: 1.13–1.25) and decreased slightly with a Linear model until it decreased to an epidemic threshold of 0.99 (95% CI: 0.65–1.34) in 2029.ConclusionsThe incidence of shigellosis is still in high level. The transmissibility of the disease is low in Hubei Province. The transmission would be interrupted in the year of 2029.

Disparities in Shigellosis Incidence by Census Tract Poverty, Crowding, and Race/Ethnicity in the United States, FoodNet, 2004-2014.

Background Shigella causes an estimated 500 000 enteric illnesses in the United States annually, but the association with socioeconomic factors is unclear.MethodsWe examined possible epidemiologic associations between shigellosis and poverty using 2004–2014 Foodborne Diseases Active Surveillance Network (FoodNet) data. Shigella cases (n = 21 246) were geocoded, linked to Census tract data from the American Community Survey, and categorized into 4 poverty and 4 crowding strata. For each stratum, we calculated incidence by sex, age, race/ethnicity, and FoodNet site. Using negative binomial regression, we estimated incidence rate ratios (IRRs) comparing the highest to lowest stratum.ResultsAnnual FoodNet Shigella incidence per 100 000 population was higher among children <5 years old (19.0), blacks (7.2), and Hispanics (5.6) and was associated with Census tract poverty (incidence rate ratio [IRR], 3.6; 95% confidence interval [CI], 3.5–3.8) and household crowding (IRR, 1.8; 95% CI, 1.7–1.9). The association with poverty was strongest among children and persisted regardless of sex, race/ethnicity, or geographic location. After controlling for demographic variables, the association between shigellosis and poverty remained significant (IRR, 2.3; 95% CI, 2.0–2.6).ConclusionsIn the United States, Shigella infections are epidemiologically associated with poverty, and increased incidence rates are observed among young children, blacks, and Hispanics.

Epidemiologic features of shigellosis and associated climatic factors in Taiwan.

The consistent, sporadic transmission of shigellosis in Taiwan necessitates an exploration of risk factors for the occurrence of shigellosis. The purpose of this study was to study the epidemiologic characteristics and the relationship between climatic factors and the incidence of shigellosis in Taiwan. We collected data from cases of shigellosis reported to the Taiwan Centers for Disease Control (Taiwan CDC) from 2001 to 2016. Climatic data were obtained from the Taiwan Central Weather Bureau. The relationships between weather variability and the incidence of shigellosis in Taiwan were determined via Poisson regression analyses. During the 16-year study period, a total of 4171 clinical cases of shigellosis were reported to the Taiwan CDC. Among them, 1926 (46.2%) were classified as confirmed cases. The incidence of shigellosis showed significant seasonality, with the majority of cases occurring in summertime (for oscillation, P < .001). The number of shigellosis cases started to increase when temperatures reached 21°C (r2 = 0.88, P < .001). Similarly, the number of shigellosis cases began to increase at a relative humidity of 70–74% (r2 = 0.75, P < .005). The number of shigellosis cases was positively associated with the mean temperature and relative humidity in the period preceding the infection. In conclusion, the occurrence of shigellosis is significantly associated with increasing temperature and relative humidity in Taiwan. Therefore, these factors could be regarded as warning signals indicating the need to implement preventive measures.

TREATMENT OF SHIGELLOSIS IN PATIENS OF ADVANCED AND SENILE AGE

The brief clinical and epidemiological analysis of incidence of shigellosis among patients of advanced and senile age in the Volgograd region for the period from 2014 to 2017 has shown in the paper. The main approaches to etiopathogenetic and symptomatic treatment of elderly patients with shigellosis have been illustrated in the article.

The Epidemiological Influence of Climatic Factors on Shigellosis Incidence Rates in Korea.

Research has shown the effects of climatic factors on shigellosis; however, no previous study has evaluated climatic effects in regions with a winter seasonality of shigellosis incidence. We examined the effects of temperature and precipitation on shigellosis incidence in Korea from 2002–2010. The incidence of shigellosis was calculated based on data from the Korean Center for Disease Control and Prevention (KCDC, Cheongju, Korea), and a generalized additive model (GAM) was used to analyze the associations between the incidence and climatic factors. The annual incidence rate of shigellosis was 7.9 cases/million persons from 2002–2010. During 2007–2010, high incidence rates and winter seasonality were observed among those aged ≥65 years, but not among lower age groups. Based on the GAM model, the incidence of shigellosis is expected to increase by 13.6% and 2.9% with a temperature increase of 1 °C and a lag of two weeks and with a mean precipitation increase of 1 mm and a lag of five weeks after adjustment for seasonality, respectively. This study suggests that the incidence of shigellosis will increase with global climate change despite the winter seasonality of shigellosis in Korea. Public health action is needed to prevent the increase of shigellosis incidence associated with climate variations.

Shigella infection in children under 5 years old in western French Guiana.

French Guiana, a tropical country, is characterised by a young and multi-ethnic population. Difficulties in accessing safe water sources lead to outbreaks of gastroenteritis. The objectives of this study were (1) to describe the microbiological profile of shigella strains isolated in western French Guiana, including antimicrobial susceptibility and the distribution of strains in terms of species and serotypes and (2) to estimate the incidence of shigellosis in children under 5 years old. A retrospective observational study was conducted of 213 cases of shigellosis diagnosed in the biology department of the hospital centre for western French Guiana between 2000 and 2012 in children under 5 years old. The serogroups (formerly known as species) that predominates in French Guiana was Shigella flexneri. No resistance was observed to fluoroquinolones or to third-generation cephalosporins. The average incidence of shigellosis in children under 5 years old in western French Guiana was estimated at 189.6 cases per 100 000 inhabitants per year. Shigellosis is a public health problem in western French Guiana. These infections suggest the difficulties in accessing safe water sources and the lack of public sanitation. A quadrivalent vaccine containing Shigella sonnei and three serotypes of S. flexneri (S. flexneri 2a, 3a and 6) could provide broad coverage against shigella infections.

Disparities in severe shigellosis among adults \u2014 Foodborne diseases active surveillance network, 2002\u20132014

BackgroundShigella causes approximately 500,000 illnesses, 6000 hospitalizations, and 40 deaths in the United States annually, but incidence and populations at risk for severe shigellosis among adults are unclear. This study describes severe shigellosis among US adults.MethodsWe analyzed Foodborne Diseases Active Surveillance Network data for infections caused by Shigella among adults ≥18 years old during 2002–2014. Criteria to define severe shigellosis included hospitalization, bacteremia, or death. We estimated annual incidence of shigellosis per 100,000 among adult populations, and conducted multivariable mixed-effects logistic regression to assess associations between severe shigellosis, demographic factors and Shigella species among adults with shigellosis.ResultsAmong 9968 shigellosis cases, 2764 (28%) were severe. Restricting to cases due to S. sonnei and S. flexneri, median annual incidence of severe shigellosis among adults was 0.56 and highest overall incidence was among black males 18–49 years old (1.58). Among adults with shigellosis, odds of severe disease were higher among males than females aged 18–49 years old (OR [95% CI] = 1.32 [1.15–1.52], p < 0.001) and among males than females with S. flexneri infections (OR [95% CI] =1.39 [1.10–1.75], p = 0.005). The odds of severe shigellosis were higher among blacks than whites (OR [95% CI] = 1.36 [1.22–1.52], p < 0.001).ConclusionsAmong adults, men 18–49 years old, particularly blacks, have the highest incidence of severe shigellosis. Among adults with shigellosis, severe shigellosis was associated with being male in age group 18–49 years, with infections caused by S. flexneri, and with black race. Future research should assess associations between severe shigellosis and sexual practices, antimicrobial resistance, comorbidities, and access to care.

Heavy precipitation as a risk factor for shigellosis among homeless persons during an outbreak — Oregon, 2015–2016

ObjectivesShigella species are the third most common cause of bacterial gastroenteritis in the United States. During a Shigella sonnei outbreak in Oregon from July 2015 through June 2016, Shigella cases spread among homeless persons with onset of the wettest rainy season on record. MethodsWe conducted time series analyses using Poisson regression to determine if a temporal association between precipitation and shigellosis incidence existed. Models were stratified by housing status. ResultsAmong 105 infections identified, 45 (43%) occurred in homeless persons. With increasing precipitation, cases increased among homeless persons (relative risk [RR] = 1.36 per inch of precipitation during the exposure period; 95% confidence interval [CI] = 1.17–1.59), but not among housed persons (RR = 1.04; 95% CI 0.86–1.25). ConclusionsHeavy precipitation likely contributed to shigellosis transmission among homeless persons during this outbreak. When heavy precipitation is forecast, organizations working with homeless persons could consider taking proactive measures to mitigate spread of enteric infections.

The effect of environmental parameters on the incidence of Shigella outbreaks in Yazd province, Iran

Abstract Climate changes have a profound effect on human health, especially when infectious diseases are concerned. Variable factors including temperature, precipitation, and relative humidity directly influence the magnitude and frequency of water-borne pathogen transfers. In this study, we determined the long-term temporal trends and seasonal patterns of shigellosis and evaluated the effects of demographic and climatic factors on its incidence in Yazd province, Iran, during 2012 through 2015. The incidence of shigellosis was highest among patients in the age group of 6–20 years and peaked in every summer of the years studied, especially during August. Furthermore, there was a significant association between climatic variables (such as monthly temperature, humidity, and atmospheric dust) and the incidence of shigellosis. However, contrary to expectations, rainfall did not affect incidence of the disease. The transmission of Shigella to humans is a complex ecological process. Socio-economic factors and lifestyle behaviours need to be addressed in future studies.

Gastroenteritis in Japanese Females Caused by Shigella flexneri without Definite Infection Route: A Case Report and Mini-Review of Literature

In Japan, the incidence of Shigellosis is low at approximately 150 cases per year, with the majority of these being imported, mainly from Asia. Sporadic domestic occurrences are also reported, the majority of which absent epidemiological association. We report a case of gastroenteritis caused by Shigella flexneri in a 60-year-old Japanese female who recovered fully following treatment with levofloxacin. While we were unable to identify the route of infection, we suspected imported frozen marine products that may have been handled or processed in an unsafe manner. Shigellosis should be included in the differential diagnosis when presented with a patient exhibiting symptoms of gastrointestinal infection, even in the absence of a history of travel to an endemic area.