Waterborne Outbreaks Research Articles

Modeling the health impact of wastewater contamination events in drinking water networks

Pathogen intrusion in drinking water systems can pose severe health risks. To better prepare in planning and responding to such events, computational models that capture the intrusion and health impact dynamics are needed. This study presents a novel benchmark testbed that integrates current knowledge on pathogen transport and fate in chlorinated systems and can assess infection risk from contamination events. The model considers organic matter degradation, chlorine decay mechanisms, pathogen inactivation kinetics, as well as stochastic water demands.We studied modeling of wastewater intrusion events that can occur anywhere within a chlorinated and non-chlorinated network. We applied the Quantitative Microbial Risk Assessment framework focusing on three pathogens: enterovirus, Campylobacter, and Cryptosporidium, and their respective dose-response models. Synthetic household-level water demand time series were used to model the individual water consumption timing and calculate the infection risk (exposure via ingestion).Model outcomes indicate that while chlorination aids mitigation, larger contaminations can still lead to infections due to chlorine resistance (for Cryptosporidium) and chlorine depletion at the contamination point. In our example scenarios, chlorine-susceptible pathogens infected of the downstream population, while chlorine-resistant ones infected the entire downstream population. Enterovirus infection risk is higher, despite the concentrations in the contamination source being lower, due to the lower susceptibility to chlorine than Campylobacter. In non-chlorinated networks, the modeled wastewater contamination events led to infection risk in the total population, depending on the contamination location. Hydraulic uncertainty had a limited influence on infection risk. Furthermore, Campylobacter’s infection risk is more sensitive to the initial concentration in the contamination source whereas enterovirus infection risk to the inactivation rate. The model further indicates that the time window for effective mitigation of the magnitude of a waterborne outbreak is short (within hours).

Wastewater-based intestinal protozoa monitoring in Shanghai, China.

Intestinal protozoa Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi have been implicated in serious waterborne outbreaks worldwide. Wastewater-based epidemiology (WBE) is a promising approach for evaluating the disease prevalence in a catchment population in that it monitors the contamination level of the intestinal pathogens in wastewater. We collected 48 urban wastewater samples (24 from influents and 24 from effluents) from the Yangpu Wastewater Treatment Plant (YPWTP) in Shanghai, China. We identified Cryptosporidium spp., G. duodenalis, and E. bieneusi by nested polymerase chain reaction (PCR) amplification. Cryptosporidium hominis and subtype IdA14 were identified in two samples by analyzing the sequences of small subunit ribosomal RNA (SSU rRNA) and 60-kDa glycoprotein (gp60) genes, respectively. The G. duodenalis sub-assemblage AII (n = 8) and assemblage C (n = 4) in 12 samples were determined by analyzing triosephosphate isomerase (tpi) gene sequences. The E. bieneusi genotype A was identified in one sample by analyzing the sequence of the internal transcribed spacer (ITS) region of the rRNA gene. These findings suggest that improving wastewater treatment and monitoring the virility of pathogens in effluents is critical. We observed similar prevalence and genotypes/subtypes of the three intestinal protozoa in our wastewater samples as those reported in previous studies, providing evidence that WBE can be used as an effective epidemic management tool.IMPORTANCECryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi are common intestinal protozoa causing diarrhea. The infective oocysts, cysts, and spores released in feces can survive in different environments, including multiple types of water bodies. Humans can acquire these intestinal protozoan infections via the fecal-oral route as in waterborne transmission. Wastewater-based epidemiology can rapidly and reliably detect and monitor the emergence and spread of waterborne diseases. We detected Cryptosporidium spp., G. duodenalis, and E. bieneusi in a wastewater treatment plant in Shanghai, China, reflecting the occurrence and genetic characterizations of the three intestinal pathogens from community members served by the wastewater treatment plant.

Measuring preparedness to infectious diseases among people exposed to climate disasters in Cabo Delgado, Mozambique: a cross-sectional study

IntroductionClimate change is contributing to increase the frequency and severity of climate disasters in Mozambique, leading, since 2019, to extensive damage to infrastructure and displacement 1.3 million people. Aim of this study is to evaluate baseline preparedness to vector-borne and water-borne infections among households and internally displaced people exposed to climate disasters in Mozambique.MethodsThis was a cross-sectional, community-based survey assessing the preparedness to infectious diseases outbreaks among people exposed to climate disasters in six districts in Mozambique. Structured form was delivered via face-to-face between October 15th and November 7th, 2022. Study outcome was defined as a seven-point score of preparedness to infectious disease outbreaks. Multivariable analysis of the score was conducted using Conway-Maxwell-Poisson regression.ResultsThis study included 2,140 households and 11,239 people, with IDPs accounting for 30% of them. Overall, 1,186 (55.4%) households were overcrowded. Median score of preparedness was 3 points (IQR 2–4). At multivariable analyses, districts with low preparedness were Montepuez and Mueda. Higher preparedness was associated with family planning (p < 0.0001), access to primary education for all children living in the household (p < 0.001) and possession of a birth certificate for all children aged < 5y (p < 0.0001), while preparedness was heterogeneous among the districts (p < 0.05). Households composed by IDPs were not associated with a lower preparedness score.ConclusionsIn climate-vulnerable communities in Mozambique, households practicing family planning, providing access to primary education and birth certificate for all children were less vulnerable to water-borne and vector-borne infectious disease outbreaks. Being family planning and childcare primarily performed by women, our findings can inform policymakers and practitioners on the importance of addressing women to mitigate the impact of climate disasters and reduce the risk of infectious disease outbreaks.

Waterborne Cryptosporidium species and Giardia duodenalis in resources of MENA: A systematic review and meta-analysis.

This review explores our understanding of Cryptosporidium species and Giardia duodenalis distribution in Middle East and North African (MENA) water resources. Results emphasize that Cryptosporidium species (sp.) and G. duodenalis (oo)cysts are present in distinct categories of water in ten MENA countries. Cryptosporidium sp. proportional prevalence in the MENA region was 24.5% (95% CI 16.3-33.8), while G. duodenalis prevalence was 37.7% (95% CI 21.9-55.1). Raw wastewater and surface water were the water categories most significantly impacted. Both parasites were reported in the various types of MENA drinking waters. The most frequent species/genotypes reported were C. hominis, C. parvum, and G. duodenalis assemblage A. Despite the high prevalence of (oo)cysts reported, we should consider the absence of waterborne outbreaks. This indicates significant underestimation and underreporting of both parasites in MENA. Stakeholders should apply water contamination legislation to eradicate Cryptosporidium sp. and G. duodenalis (oo)cysts from water resources/categories.

Machine learning and explainable artificial intelligence for the prevention of waterborne cryptosporidiosis and giardiosis

Cryptosporidium and Giardia are important parasitic protozoa due to their zoonotic potential and impact on human health, and have often caused waterborne outbreaks of disease. Detection of (oo)cysts in water matrices is challenging and extremely costly, thus only few countries have legislated for regular monitoring of drinking water for their presence. Several attempts have been made trying to investigate the association between the presence of such (oo)cysts in waters with other biotic or abiotic factors, with inconclusive findings. In this regard, the aim of this study was the development of an holistic approach leveraging Machine Learning (ML) and eXplainable Artificial Intelligence (XAI) techniques, in order to provide empirical evidence related to the presence and prediction of Cryptosporidium oocysts and Giardia cysts in water samples. To meet this objective, we initially modelled the complex relationship between Cryptosporidium and Giardia (oo)cysts and a set of parasitological, microbiological, physicochemical and meteorological parameters via a model-agnostic meta-learner algorithm that provides flexibility regarding the selection of the ML model executing the fitting task. Based on this generic approach, a set of four well-known ML candidates were, empirically, evaluated in terms of their predictive capabilities. Then, the best-performed algorithms, were further examined through XAI techniques for gaining meaningful insights related to the explainability and interpretability of the derived solutions. The findings reveal that the Random Forest achieves the highest prediction performance when the objective is the prediction of both contamination and contamination intensity with Cryptosporidium oocysts in a given water sample, with meteorological/physicochemical and microbiological markers being informative, respectively. For the prediction of contamination with Giardia, the eXtreme Gradient Boosting with physicochemical parameters was the most efficient algorithm, while, the Support Vector Regression that takes into consideration both microbiological and meteorological markers was more efficient for evaluating the contamination intensity with cysts. The results of the study designate that the adoption of ML and XAI approaches can be considered as a valuable tool for unveiling the complicated correlation of the presence and contamination intensity with these zoonotic parasites that could constitute, in turn, a basis for the development of monitoring platforms and early warning systems for the prevention of waterborne disease outbreaks.

Food and Drinking Water as Sources of Pathogenic Protozoans: An Update

This narrative review was aimed at collecting updated knowledge on the risk factors, illnesses caused, and measures for the prevention of protozoan infections transmitted by food and drinking water. Reports screened dated from 2019 to the present and regarded global prevalence in food handlers, occurrence in food and drinking water, impact on human health, and recently reported outbreaks and cases of severe infections attributable to the dietary route. Cryptosporidium spp., Cyclospora cayetanensis, Entamoeba histolytica, and Cystoisospora belli were the protozoans most frequently involved in recently reported waterborne and foodborne outbreaks and cases. Blastocystis hominis was reported to be the most widespread intestinal protozoan in humans, and two case reports indicated its pathogenic potential. Dientamoeba fragilis, Endolimax nana, and Pentatrichomonas hominis are also frequent but still require further investigation on their ability to cause illness. A progressive improvement in surveillance of protozoan infections and infection sources took place in developed countries where the implementation of reporting systems and the application of molecular diagnostic methods led to an enhanced capacity to identify epidemiological links and improve the prevention of foodborne and waterborne protozoan infections.

Diverse genotypes of norovirus genogroup I and II contamination in environmental water in Thailand during the COVID-19 outbreak from 2020 to 2022

Noroviruses (NoVs) are the most significant viral pathogens associated with waterborne and foodborne outbreaks of nonbacterial acute gastroenteritis in humans worldwide. This study aimed to investigate the prevalence and diversity of NoVs contaminated in the environmental water in Chiang Mai, Thailand. A total of 600 environmental water samples were collected from ten sampling sites in Chiang Mai from July 2020 to December 2022. The presence of NoV genogroups I (GI), GII, and GIV were examined using real-time RT-PCR assay. The genotype of the virus was determined by nucleotide sequencing and phylogenetic analysis. The results showed that NoV GI and GII were detected at 8.5% (51/600) and 11.7% (70/600) of the samples tested, respectively. However, NoV GIV was not detected in this study. NoV circulated throughout the year, with a higher detection rate during the winter season. Six NoV GI genotypes (GI.1-GI.6) and eight NoV GII genotypes (GII.2, GII.3, GII.7, GII.8, GII.10, GII.13, GII.17, and GII.21) were identified. Among 121 NoV strains detected, GII.17 was the most predominant genotype (24.8%, 30 strains), followed by GII.2 (21.5%, 26 strains), GI.3 (17.4%, 21 strains), and GI.4 (16.5%, 20 strains). Notably, NoV GII.3, GII.7, GII.8, and GII.10 were detected for the first time in water samples in this area. This study provides insight into the occurrence and seasonal pattern of NoV along with novel findings of NoV strains in environmental water in Thailand during the COVID-19 outbreak. Our findings emphasize the importance of further surveillance studies to monitor viral contamination in environmental water.

Outbreak of waterborne acute diarrheal disease in a South District village of Tripura: A public health emergency in the Northeast region of India

Food and waterborne outbreaks are a neglected public health problem in India. However, it is important to identify the source of infection and the causative pathogen to curb the outbreak quickly and minimize mortality and morbidity. A retrospective descriptive study was conducted with a line list of 130 diarrheal cases. Epidemiological investigation and laboratory investigation were done. Data were collected from hospital case report forms as well as interviewed affected cases. A case of acute diarrheal disease was reported among the people in the village with abdominal pain, vomiting, and diarrhea from December 31, 2022 to January 3, 2023. Out of a total of 130 recorded cases, 33 stool samples were collected and were positive for Enteroaggregative Escherichia coli, Shigella flexneri 3a, and Shigella sonnei by cultural and molecular tests. The presumptive fecal pollution indicator assay indicated high coliform counts in the water samples (most probable number [MPN]-05) and the presence of Escherichia coli. The identified pathogens showed susceptibility to gentamicin and meropenem. People who used public drinking water were found to be infected with acute diarrheal disease (ADD). Quick identification of the causative pathogens and their antimicrobial resistance pattern helped correct antibiotic prescriptions and quick recovery of the patients without any deaths. Thus, a timely implementation of food and waterborne outbreak investigation is crucial to saving lives and preventing the spread of infection.

Development and evaluation of test methods for the detection and enumeration of opportunistic waterborne pathogens from the hospital environment

Many Gram-negative bacteria other than Pseudomonas aeruginosa have been implicated in waterborne outbreaks, but standardized laboratory detection methods for these organisms have not been established. This study aimed to establish laboratory testing methodologies for six waterborne pathogens: Acinetobacter spp., Burkholderia spp., Cupriavidus spp., Delftia acidovorans, Elizabethkingia spp. and Stenotrophomonas maltophilia. Water samples were spiked by UK Health Security Agency laboratories and sent to the Glasgow Royal Infirmary laboratory for analysis. Water samples were spiked with either a pure culture of target organism or the target organism in water containing normal background flora, to ensure that the methodology could identify organisms from a mixed culture. Volumes of 100mL were filtered under negative pressure on to culture media and incubated at 30°C and 37°C. The incubation time was 7 days, with plates read on days 2, 5 and 7. Further identification of colonies was undertaken using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Optimal recovery of organisms was obtained by culturing water samples on tryptic soy agar, chocolate bacitracin agar and pseudomonas selective agar. The optimal temperature for isolation was 30°C. The optimal incubation time was 5 days, and MALDI-TOF MS identified all test species reliably. The methodology described was able to detect the six tested waterborne pathogens reliably, and can be utilized by laboratories involved in testing water samples during outbreak investigations.

A rare waterborne outbreak of Bacillus paranthracis in Shandong province, China, 2020: epidemiologic survey, genomic insights, and virulence characteristics

ABSTRACT Bacillus paranthracis, a Gram-positive conditional pathogen of Bacillus cereus group species, is capable of causing foodborne and waterborne illnesses, leading to intestinal diseases in humans characterized by diarrhoea and vomiting. However, documented cases of B. paranthracis infection outbreaks are rare in the world, and the genomic background of outbreak strains is seldom characterized. This study retrospectively analyzed strains obtained from an outbreak in schools, as well as from water systems in peri-urban areas, China, in 2020. In total, 28 B. cereus group isolates were retrieved, comprising 6 from stool samples and 22 from water samples. Epidemiological and phylogenetic investigations indicated that the B. paranthracis isolate from drinking water as the causative agent of the outbreak. The genomic comparison revealed a high degree of consistency among 8 outbreak-related strains in terms of antimicrobial resistance gene profiles, virulence gene profiles, genomic content, and multilocus sequence typing (MLST). The strains related to the outbreak show highly similar genomic ring diagrams and close phylogenetic relationships. Additionally, this study shed light on the pathogenic potential and complexity of B. cereus group through its diversity in virulence genes and mice infection model. The findings highlight the usefulness of B. paranthracis genomes in understanding genetic diversity within specific environments and in tracing the source of pathogens during outbreak situations, thereby enabling targeted infection control interventions.

Classical and molecular detection methods in aquatic environmental virology for waterborne diseases outbreaks

Classical and molecular detection methods in aquatic environmental virology for waterborne diseases outbreaks

Surveillance of Waterborne Disease Outbreaks Associated with Drinking Water - United States, 2015-2020.

Public health agencies in U.S. states, territories, and freely associated states investigate and voluntarily report waterborne disease outbreaks to CDC through the National Outbreak Reporting System (NORS). This report summarizes NORS drinking water outbreak epidemiologic, laboratory, and environmental data, including data for both public and private drinking water systems. The report presents outbreak-contributing factors (i.e., practices and factors that lead to outbreaks) and, for the first time, categorizes outbreaks as biofilm pathogen or enteric illness associated. 2015-2020. CDC launched NORS in 2009 as a web-based platform into which public health departments voluntarily enter outbreak information. Through NORS, CDC collects reports of enteric disease outbreaks caused by bacterial, viral, parasitic, chemical, toxin, and unknown agents as well as foodborne and waterborne outbreaks of nonenteric disease. Data provided by NORS users, when known, for drinking water outbreaks include 1) the number of cases, hospitalizations, and deaths; 2) the etiologic agent (confirmed or suspected); 3) the implicated type of water system (e.g., community or individual or private); 4) the setting of exposure (e.g., hospital or health care facility; hotel, motel, lodge, or inn; or private residence); and 5) relevant epidemiologic and environmental data needed to describe the outbreak and characterize contributing factors. During 2015-2020, public health officials from 28 states voluntarily reported 214 outbreaks associated with drinking water and 454 contributing factor types. The reported etiologies included 187 (87%) biofilm associated, 24 (11%) enteric illness associated, two (1%) unknown, and one (<1%) chemical or toxin. A total of 172 (80%) outbreaks were linked to water from public water systems, 22 (10%) to unknown water systems, 17 (8%) to individual or private systems, and two (0.9%) to other systems; one (0.5%) system type was not reported. Drinking water-associated outbreaks resulted in at least 2,140 cases of illness, 563 hospitalizations (26% of cases), and 88 deaths (4% of cases). Individual or private water systems were implicated in 944 (43%) cases, 52 (9%) hospitalizations, and 14 (16%) deaths.Enteric illness-associated pathogens were implicated in 1,299 (61%) of all illnesses, and 10 (2%) hospitalizations. No deaths were reported. Among these illnesses, three pathogens (norovirus, Shigella, and Campylobacter) or multiple etiologies including these pathogens resulted in 1,225 (94%) cases. The drinking water source was identified most often (n = 34; 7%) as the contributing factor in enteric disease outbreaks. When water source (e.g., groundwater) was known (n = 14), wells were identified in 13 (93%) of enteric disease outbreaks.Most biofilm-related outbreak reports implicated Legionella (n = 184; 98%); two nontuberculous mycobacteria (NTM) (1%) and one Pseudomonas (0.5%) outbreaks comprised the remaining. Legionella-associated outbreaks generally increased over the study period (14 in 2015, 31 in 2016, 30 in 2017, 34 in 2018, 33 in 2019, and 18 in 2020). The Legionella-associated outbreaks resulted in 786 (37%) of all illnesses, 544 (97%) hospitalizations, and 86 (98%) of all deaths. Legionella also was the outbreak etiology in 160 (92%) public water system outbreaks. Outbreak reports cited the premise or point of use location most frequently as the contributing factor for Legionella and other biofilm-associated pathogen outbreaks (n = 287; 63%). Legionella was reported to NORS in 2015 and 2019 as the cause of three outbreaks in private residences (2). The observed range of biofilm and enteric drinking water pathogen contributing factors illustrate the complexity of drinking water-related disease prevention and the need for water source-to-tap prevention strategies. Legionella-associated outbreaks have increased in number over time and were the leading cause of reported drinking water outbreaks, including hospitalizations and deaths. Enteric illness outbreaks primarily linked to wells represented approximately half the cases during this reporting period. This report enhances CDC efforts to estimate the U.S. illness and health care cost impacts of waterborne disease, which revealed that biofilm-related pathogens, NTM, and Legionella have emerged as the predominant causes of hospitalizations and deaths from waterborne- and drinking water-associated disease. Public health departments, regulators, and drinking water partners can use these findings to identify emerging waterborne disease threats, guide outbreak response and prevention programs, and support drinking water regulatory efforts.

Design and evaluation of loop-mediated isothermal amplification for rapid detection of Enterocytozoon bieneusi

Enterocytozoon bieneusi is one of the most prevalent microsporidia species, responsible for more than 90% of human and animal microsporidiosis. Microsporidia species, particularly E. bieneusi, are frequently reported from waterborne and foodborne outbreaks. Therefore, early detection is crucial in clinics and outbreak investigations. This study aimed to design a loop-mediated isothermal amplification (LAMP) for rapid detection of E. bieneusi. Total DNA was extracted from 30 E. bieneusi –positive samples, which had been confirmed with nested PCR. LAMP primers were designed based on the identical fragment of small subunit ribosomal RNA (SSU rRNA) gene. LAMP reactions were performed at 63 °C for 60 min. The sensitivity and specificity of the assay were analyzed and the results of amplification were compared to real-time PCR. Our results showed that the LAMP assay successfully amplified 25/30 (83.3%) samples. The specificity results indicated no false positive with other microorganisms. Furthermore, the LAMP method exhibited a sensitivity (limit of detection, LoD) as low as 34 ag/μL of total DNA. Compared to the LAMP assay, real-time PCR was able to detect all 30 nested PCR-positive samples. Our findings showed that the LAMP assay was able to detect 83.3% of E. bieneusi-positive samples. Although the current assay was not able to detect all nested PCR-positive samples, the lack of need for specific instruments, rapid processes, and high specificity makes LAMP assay a suitable tool for screening.

Norovirus GII.17 Caused Five Outbreaks Linked to Frozen Domestic Bilberries in Finland, 2019.

In March 2019, the Finnish Institute for Health and Welfare and Finnish Food Authority started an outbreak investigation after a notification of food business operators' recall of frozen bilberries due to a norovirus finding. A retrospective search was conducted in the food and waterborne outbreak notification system to identify the notifications linked to norovirus and consumption of bilberries in January-March 2019. Five outbreaks were found in which norovirus GII or GII.17 had been detected in patient samples. A pooled retrospective cohort study was performed for those four in which a questionnaire study had been done. A case was defined as a person with diarrhoea or vomiting within 2 days after consuming a meal studied at one of the outbreak locations. Of 79 participants, 45 (57%) cases were identified. Persons that had consumed foods containing unheated bilberries were three times more likely to get ill than those who had not consumed them (RR 3.1, CI 95% 1.2-8.1, p = 0.02). Norovirus GII.17 was found in 16/17 patient samples sent for further typing. Identical norovirus GII.17 was detected in frozen Finnish bilberries and patient samples. At the berry packaging premises, signs of norovirus GII contamination were found in packaging lines. A new procedure for extracting viral nucleic acid from food and environmental samples was used during the outbreak investigation. Consumption of industrially packed frozen berries as heated would be one of the means to prevent norovirus infections.

An Investigation into the Microbiological Quality of Groundwater in an Industrial Hub in Mid-Hills of Northern India

Frequent water-borne disease outbreaks affecting human health have been reported in district Solan, which is a rapidly industrialing region of Himachal Pradesh, a northern state of India. For ascertaining the cause, microbiological assessment of drinking groundwater sources of the region was undertaken. For this, thermotolerant coliform study and genome typing were undertaken. Multiple tube fermentation technique was employed in selected five sources to detect thermotolerant coliforms during the seasons of monsoon and post-monsoon in the years 2018-19. Thermotolerant coliforms varied in Most Probable Number from 2-34 per 100 ml water indicating contaminated water sources, densities being significantly more in monsoon months (p&lt; 0.05). Four different coliform morphotypes were obtained from all the sources on Eosin Methylene Blue plates. Of these, the only strain, designated as Nalagarh Water Strain (NGW), was recovered from all sources, suggesting its prevalence. Based upon biochemical and morphological attributes, the strain was recognized as Escherichia coli. Conversely, molecular characterization (16S rRNA ribotyping) identified it as Raoultella planticola (GenBank accession No. MK318824). The strain was deposited in a National Culture Collection Centre, National Centre for Microbial Resources, Pune, Maharashtra (India) with deposition accession number MCC 4064 for future utility in public research activities. Microbiological assessment evinced contaminated drinking water sources, probably causing diarrhoeal diseases. 16S rRNA ribotyping assisted in correct identification of the microorganism.

Campylobacteriosis in Finland: Passive Surveillance in 2004-2021 and a Pilot Case-Control Study with Whole-Genome Sequencing in Summer 2022.

Campylobacteriosis causes a significant disease burden in humans worldwide and is the most common type of zoonotic gastroenteritis in Finland. To identify infection sources for domestic Campylobacter infections, we analyzed Campylobacter case data from the Finnish Infectious Disease Register (FIDR) in 2004-2021 and outbreak data from the National Food- and Waterborne Outbreak Register (FWO Register) in 2010-2021, and conducted a pilot case-control study (256 cases and 756 controls) with source attribution and patient sample analysis using whole-genome sequencing (WGS) in July-August 2022. In the FIDR, 41% of the cases lacked information on travel history. Based on the case-control study, we estimated that of all cases, 39% were of domestic origin. Using WGS, 22 clusters of two or more cases were observed among 185 domestic cases, none of which were reported to the FWO register. Based on this case-control study and source attribution, poultry is an important source of campylobacteriosis in Finland. More extensive sampling and comparison of patient, food, animal, and environmental isolates is needed to estimate the significance of other sources. In Finland, campylobacteriosis is more often of domestic origin than FIDR notifications indicate. To identify the domestic cases, travel information should be included in the FIDR notification, and to improve outbreak detection, all domestic patient isolates should be sequenced.

Cryptosporidium and irritable bowel syndrome.

Cryptosporidium is an apicomplexan parasite that causes gastrointestinal disease in a wide variety of hosts and is associated with waterborne outbreaks. Nonetheless, the parasite is underdiagnosed. Cryptosporidium has been proposed as an etiological cause of irritable bowel syndrome (IBS) in several studies. However, the exact mechanism of pathogenesis is unknown, and no direct link has been discovered. This review will discuss several parasite-induced modifications, such as immunological, microbiome, and metabolite modifications, as well as their interactions. To summarize, Cryptosporidium causes low inflammation, dysbiosis, and unbalanced metabolism, which leads to a lack of homeostasis in the intestine in a comparable pattern to postinfectious IBS.

Flood and Dengue: Increased risk of Gestational Pestilences.

Madam Editor, Dengue fever is an acute viral disease caused by an RNA (Ribonucleic Acid) virus transmitted by Aedes mosquitoes. Symptoms can range from asymptomatic fever to life-threatening complications such as haemorrhagic fever and shock (1). Dengue fever is recognized by the (WHO (World Health Organization)) World Health Organization as a serious global public health threat in tropical and subtropical countries. Dengue-endemic regions are home to 2.5 billion people, and 400 million infections occur each year, with mortality rates exceeding 20% in some areas (2). Extremely heavy rains have lately devastated Pakistan, with its most populous metropolis of Karachi witnessing the worst floods in a century. Flooding and inadequate water sanitation have increased the risk of dengue, malaria, and other water-borne disease outbreaks. Determining whether dengue infection during pregnancy is associated with adverse effects on the fetus is important, given that women of reproductive age in dengue-endemic areas are at risk of contracting the disease. Studies have suggested an association between maternal infection during pregnancy and preterm birth, low birth weight, small gestational age births, stillbirth, and miscarriage (3, 4). According to Pouliot SH, et al., high rates of cesarean deliveries (44%) and pre-eclampsia (12%) occurred in women who had dengue infection during pregnancy (5). Even though there are several variants of dengue infection, the study found that the proportion of DENV-4 in pregnant women was higher than in non-pregnant women (6), the reason for which is still unclear. The gestational period involves various anatomical and physiological changes in the female body, such as increased capillary permeability, hemodilution, leukocytosis, thrombocytopenia, etc., which may complicate the assessment of the clinical manifestation of dengue due to opposing effects on the body, such as the contradicting leucocyte concentration, as pregnancy causes leukocytosis, whereas dengue causes leukopenia (6). Though the exact mechanism of the effect of maternal dengue on the fetus is yet to be determined, recent studies have put forward two mechanisms for fetal and neonatal morbidity caused by maternal dengue infection. The first theory is that dengue infection causes hemodynamic changes during pregnancy that could affect the placenta and cause fetal hypoxia, In contrast, the second theory states that dengue infection affects the fetus directly (7). ---Continue

Characteristics and related factors of waterborne and foodborne infectious disease outbreaks before and after the onset of the COVID-19 pandemic (2017-2021) in the Republic of Korea: a descriptive study.

The incidence of waterborne and foodborne infectious diseases (WFIDs) continues to increase annually, attracting significant global attention. This study examined trends in WFID outbreaks in the Republic of Korea over the 5-year period before and during the coronavirus disease 2019 (COVID-19) pandemic and provided foundational data to establish measures for the prevention and control of WFID outbreaks. We analyzed 2,541 WFID outbreaks from 2017 to 2021 (42,805 cases) that were reported through the Integrated Disease Surveillance System of the Korea Disease Control and Prevention Agency. Outbreaks were defined as the occurrence of gastrointestinal symptoms in ≥2 individuals within a group with temporal and regional epidemiological associations. The related factors associated with WFID outbreaks during the observation period were statistically analyzed. The total number of WFID outbreaks significantly decreased in 2020 during the COVID-19 pandemic and increased to the pre-pandemic level in 2021. Different patterns were observed for each pathogen. The incidence of Salmonella outbreaks more than doubled, while norovirus outbreaks decreased significantly. WFID outbreaks in the Republic of Korea showed different patterns before and during the COVID-19 pandemic, influenced by infection control measures and changes in dietary consumption patterns. Outbreaks of some diseases increased, but the infection control measures applied during the pandemic resulted in a significant decrease in the overall number of WFID outbreaks. This highlights the importance of strengthening the management strategies for outbreak prevention through hygiene inspections, long-term monitoring, education, and promotion by conducting multidimensional analyses to understand the complex related factors.

Implementing risk-based approaches to improve drinking water quality in small water supplies in the Nordic region - barriers and solutions.

Small water supplies face similar problems worldwide, regardless of ownership or management type. Non-compliance with water quality regulations is more frequent in small supplies than in large ones, as are waterborne disease outbreaks. The new European Union Drinking Water Directive requires risk-based approach (RBA) to secure water safety as is recommended in the World Health Organization's Guidelines for drinking water quality through 'water safety plans'. This is already in regulation in the Nordic countries, although less used in small supplies. In this research, we explore the challenges, barriers and possible solutions to implementing RBA and improving compliance in small supplies. This was achieved by conducting and analysing interviews with 53 stakeholders from all eight Nordic countries to produce recommendations for action by the different implicated actors. Our findings suggest the centrality of governmental policy, including support for continuous training, provision of simple RBA guidelines and increasing cooperation in the water sector. The Nordic experience reflects global challenges with small water supplies and the trend towards systematic preventive management epitomized in the framework for drinking water safety advocated by the World Health Organization since 2004.