Risk Factors For Sporadic Infections Research Articles

Risk factors for sporadic hepatitis A infection: A systematic review and meta-analysis

Hepatitis A virus (HAV) is responsible for common acute viral hepatitis worldwide. Improvement in sanitation and use of efficient vaccines have reduced HAV incidence in developed countries. However, naive adult population are most susceptible to severe outcomes, and high endemic areas persist in developing regions. The transmission of HAV through the fecal-oral route is established. However, considering evolving consumption habits and global market exchange of food, investigations on risk factors associated with HAV infection are needed. Thus, a systematic review and a meta-analysis of case-control, cohort and transversal studies was performed to determine the main risk factors associated with sporadic HAV infection. Relevant scientific articles were identified through systematic literature search and subjected to a methodological quality assessment. Mixed-effects meta-analyses models were adjusted by population type to appropriate data partitions. HAV infections are defined by serological testing. The quality assessment stage selected 78 studies investigating risk factors for sporadic infections with hepatitis A conducted between 1985 and 2013. This meta-analysis confirmed that HAV infections are mostly related to inter-human transmissions, either due to contact with an ill person, through oral-anal sex practice, or lack of personal hygiene. Travel to endemic countries, occupational exposure such as working in child daycare, and exposure to wastewater were associated with HAV infection. As HAV can persist in the environment, it was not surprising that consumption of untreated drinking water, shellfish consumed raw, and crop products were risk factors. Food contamination could be due to the use of contaminated water (fruits, vegetables) or originate from infected food handlers at every point of the food chain (from picking to serving). Eating or drinking outside were associated with HAV infection. A lack of recent case-control studies was identified, with only three studies eligible between 2011 and 2017. Case-control studies required a more precise definition of risk factors such as type of crop product, and storing/preparation information (e.g. washed, frozen). The frequency of consumption or duration of environmental exposure could also better inform relationship between exposure and risk of infection. In a context of epidemiological change of HAV, international travel and trade of foods, future case-control studies are needed and should focus on populations at risk of severe infections and acute cases.

Risk factors for sporadic toxoplasmosis: A systematic review and meta-analysis

Toxoplasmosis is considered as the most prevalent parasitic zoonotic infection worldwide. The parasitic cycle is mostly known, but the relative contribution of different sources and pathways of transmission was not previously studied by a meta-analysis. A systematic review and a meta-analysis of case-control, cohort, and cross-sectional studies were performed to determine the main risk factors associated with sporadic Toxoplasma infection. Suitable scientific articles were identified through a systematic literature search and subjected to a methodological quality assessment. Mixed-effects meta-analysis models were adjusted by population type – children, mixed population, and pregnant women – to appropriate data partitions. 187 primary studies passed the quality assessment stage, investigating risk factors for sporadic infection with Toxoplasma gondii conducted between 1983 and 2016. Cases were defined by serology.The meta-analysis of Toxoplasma sporadic infections revealed the significance of transmission by environmental factors such as contact with soil and contact with animals, in particular cats. The consumption of raw or undercooked meat and unwashed vegetables significantly increased the odds of acquiring the disease. Shellfish and raw milk were identified as significant sources of toxoplasmosis. Almost all meat categories were identified as risk factors: pork, poultry, beef, processed meat, lamb, and game meat. Contaminated drinking water may play a role in the acquisition of infection. Moreover, the lack of hygiene in preparing food was identified as a risk factor. A significant risk factor for pregnant women is traveling abroad. Lastly, blood transfusion (in pregnant women) and immunocompromised conditions were found associated with positive serology. The broad definition of exposures and the use of serology for the case definition are the main limitations for the interpretation of the results of this meta-analysis. The transmission pathways require further investigations using longitudinal studies and subtyping approaches.

Risk factors for sporadic infections caused by Shiga toxin-producing Escherichia coli: a systematic review and meta-analysis

Shiga toxin-producing Escherichia coli (STEC) are an important cause of foodborne disease associated with clinical outcomes ranging from mild intestinal discomfort to haemolytic uremic syndrome, including end-stage renal disease and death. The objective of this study was to synthetize evidence on risk factors for sporadic STEC infection by meta-analysing outcomes from available case-control studies. Suitable scientific articles were identified through a systematic literature search, and assessed for methodological quality. From each study, odds ratios (OR) were extracted along with study characteristics such as the population, design, statistical model used and risk factor hierarchy. Mixed-effects meta-analytical models were adjusted by population type to appropriate data partitions. The quality assessment stage was passed by 29 studies investigating sporadic STEC infection conducted between 1986 and 2013. These studies provided 493 ORs for meta-analysis. The main risk factors for STEC infection were foreign travel, contact with ill people, farm animals or their environment, food consumption and exposure to untreated drinking water. Concerning food exposures, this meta-analysis confirmed known risk factors, such as consumption of beef (especially when undercooked) and other meats (barbecued meat, donner kebab meat and meat casseroles), processed meat, ready-to-eat meat, composite foods, and raw milk consumption by children. Newly identified food vehicles were chicken and fish. Produce (fruits/vegetables) was not associated with sporadic STEC infection.

Risk Factors for Sporadic Infection With Campylobacter Spp. Among Children in Israel: A Case-control Study.

Campylobacter spp. has been identified as one of the leading causes of bacterial gastroenteritis in the world. In recent years, an increase in the incidence of campylobacteriosis in several countries, including Israel, was demonstrated. The incidence rate of campylobacteriosis in Israel increased from 22.3 per 100,000 in 1997 to 77.4 per 100,000 in 2009. The aim of this study was to explore risk factors for sporadic infection with Campylobacter among young children in Israel. A matched case-control study was performed to investigate risk factors for sporadic Campylobacter infection among 113 affected children of 1-5 years of age and 113 age-matched, gender-matched and neighborhood-matched controls. Information about exposure to potential risk factors was obtained via telephone interview and was evaluated by conditional logistic regression analysis. In the multivariable model, for each additional chicken meal consumed during the week before the onset of illness, the odds for Campylobacter infection increased by 32% [adjusted matched odds ratios (aMOR): 1.32; 95% confidence interval (CI): 1.01-1.72; P = 0.04], whereas consumption of fruits and vegetables decreased the odds for Campylobacter infection by 97% (aMOR: 0.03; 95% CI: 0.00-0.28; P < 0.01), and for each additional child living in the household, the odds for infection decreased by 48% (aMOR: 0.52; 95% CI: 0.33-0.83; P < 0.01). Using diaper increased the odds for campylobacteriosis (aMOR: 7.36; 95% CI: 1.66-32.70; P < 0.01). Interventions that focus on proper handling of chicken and chicken products, hand washing and encouraging consumption of fruits and vegetables could help in controlling Campylobacter infections.

Risk factors for sporadic Salmonella Birkenhead infection in Queensland and northern New South Wales: A case control study

Salmonella Birkenhead is one of the most commonly notified causes of gastroenteritis in southern Queensland and northern New South Wales. It is notified infrequently in other areas of Australia. This limited geographical distribution suggests a possible environmental source. A case control study was conducted to explore risk factors for sporadic infection with Salmonella Birkenhead and to inform interventions to reduce the incidence of human infection.

Risk factors for sporadic giardiasis: a case-control study in southwestern England.

To investigate risk factors for sporadic infection with Giardia lamblia acquired in the United Kingdom, we conducted a matched case-control study in southwest England in 1998 and 1999. Response rates to a postal questionnaire were 84% (232/276) for cases and 69% (574/828) for controls. In multivariable analysis, swallowing water while swimming (p<0.0001, odds ratio [OR] 6.2, 95% confidence intervals [CI] 2.3 to 16.6), recreational fresh water contact (p=0.001, OR 5.5, 95% CI 1.9 to 15.9), drinking treated tap water (p<0.0001, OR 1.3, 95% CI 1.1 to 1.5 for each additional glass per day), and eating lettuce (pç=0.01, OR 2.2, 95% CI 1.2 to 4.3) had positive and independent associations with infection. Although case-control studies are prone to bias and the risk of Giardia infection is minimized by water treatment processes, the possibility that treated tap water is a source of sporadic giardiasis warrants further investigation.

An increase in sporadic and outbreak-associated Salmonella enteritidis infections in Wisconsin: the role of eggs.

In Wisconsin, reported Salmonella enterica serotype enteritidis (SE) infections during 1997 more than doubled compared with the previous 9 years. A case-control study was conducted to determine risk factors for sporadic infections, and results of outbreak investigations were reviewed. Eating raw eggs (matched odds ratio [MOR]=14.5; 95% confidence interval [CI], 1.7-591.6), eating raw or undercooked eggs (MOR=5.8; 95% CI, 1.3-28.0), eating any eggs (MOR=4.2; 95% CI, 1.2-16.2), and dining at a restaurant (MOR=4.7; 95% CI, 1.4-18.4) were associated with infection in the case-control study. For 3 of the 8 outbreaks, a probable source was identified, in each instance, foods containing eggs. Human infections decreased after eggs were diverted from implicated flocks. This epidemic demonstrates the continuing need for quality assurance on egg farms and enhanced education of consumers and commercial food preparers regarding safe handling of eggs.

Risk factors for sporadic infection with Escherichia coli O157:H7

Risk factors for sporadic infection with Escherichia coli O157:H7

Risk Factors for Sporadic Infection With Escherichia coli 0157:H7

Little is known about risk factors for sporadic infection with Escherichia coli O157:H7. In response to a sharp increase in reported cases in New Jersey during July 1994, we conducted a case-control study to identify principal sources of infection and contributing practices. Standardized questionnaires were used to evaluate (1) potential exposures of case patients and matched controls and (2) knowledge, attitudes, and practices of food preparers in case and control households. Patient isolates were subtyped by pulsed-field gel electrophoresis. Patients with E coli O157:H7 infection (N = 23; median age, 9 years; 55% female) were more likely than healthy controls to have eaten a hamburger in the week preceding illness (matched odds ratio, undefined; P < .001); 80% of the hamburgers eaten by ill persons were prepared at home. Food preparers in case households were less likely than those in control households to report washing their hands (odds ratio, 8.5; P < .005) and work surfaces (odds ratio, 10.5; P < .05) after handling raw ground beef. Pulsed-field gel electrophoresis yielded 17 unique subtypes among the 23 patient isolates, indicating multiple sources of infection. Hamburgers prepared at home are an important source of sporadic E coli O157:H7 infections. We estimate that adequate hand washing by food preparers could have prevented 34% of E coli O157:H7 infections in the study population.

Risk factors for sporadic Campylobacter infections: results of a case-control study in southeastern Norway.

In 1989 and 1990, a case-control study designed to identify risk factors for sporadic infections with thermotolerant Campylobacter bacteria was conducted in three counties in southeastern Norway. The investigation was confined to infections which were acquired in Norway. A total of 52 bacteriologically confirmed cases and 103 controls matched by age, sex, and geographic region were interviewed. The following risk factors were found to be independently associated with illness in conditional logistic regression analysis: consumption of sausages at a barbecue (odds ratio [OR] = 7.64; P = 0.005), daily contact with a dog (OR = 4.26; P = 0.024), and eating of poultry which was brought into the house raw (frozen or refrigerated) (OR = 3.20; P = 0.024). The risk associated with consumption of sausages at a barbecue could not be attributed to cross-contamination from poultry products. By univariate analysis, consumption of poultry which was brought raw and frozen was associated with illness (OR = 2.42; P = 0.042), even though freezing substantially reduces the number of viable campylobacters. When poultry consumption was examined by country of origin, eating of poultry produced in Denmark or Sweden was strongly associated with illness (OR = 13.66; P = 0.014), whereas consumption of poultry produced in Norway was not (OR = 1.33; P = 0.41).