Browsing by Author "Thébault, Anne"
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- Risk factors for sporadic campylobacteriosis: a systematic review and meta-analysisPublication . Fravalo, Philippe; Kooh, Pauline; Mughini-Gras, Lapo; David, Julie; Thébault, Anne; Cadavez, Vasco; Gonzales-Barron, UrsulaCampylobacter spp. is an important causative agent of diarrheal illness worldwide. The disease is frequently associated with foodborne transmission, but other routes of exposure are increasingly recognized. A systematic review and meta-analysis of case-control studies were performed to determine the main risk factors associated with sporadic campylobacteriosis. Suitable scientific articles published up to March 2017 were identified through a systematic literature search and subject to methodological quality assessment. From each study, odds ratios (OR) as measures of association were extracted or calculated, as well as study characteristics such as study population, design, type of model used and risk factor categorization. Mixed-effects meta-analytical models were adjusted by population type to appropriate data partitions. From 4453 identified references, the quality assessment stage was passed by 71 case-control studies focusing on sporadic campylobacteriosis. The eligible studies were conducted between 1981 and 2012 and provided 1336 ORs for meta-analysis. The meta-analysis identified international travel (pooled OR=4.626), recent use of gastric antacids (pooled OR=2.911), occupational exposure to animals/carcasses (pooled OR=3.022), and food consumption (in particular raw or undercooked eggs, poultry, beef, and dairy) as the main risks factors for sporadic campylobacteriosis in the mixed population. In the child population, the main risk factors concerned environmental/animal transmission routes (e.g. drinking untreated water (pooled OR=3.261), exposure to recreational water (pooled OR=3.156), exposure to farm/rural environment (pooled OR=3.128), contact with farm animals (pooled OR=2.747), person-to-person transmission (pooled OR=2.736) and consumption of raw milk (pooled OR =2.603). The results of this meta-analysis highlight the importance of overlooked routes and vehicles of transmission (environment, animal contact, and other food vehicles) of Campylobacter that should be explored in dedicated studies.
- Risk factors for sporadic cryptosporidiosis: a systematic review and meta-analysisPublication . Kooh, Pauline; Thébault, Anne; Cadavez, Vasco; Gonzales-Barron, Ursula; Villena, IsabelleCryptosporidium spp. is an important cause of gastrointestinal disease worldwide, responsible for 69 million cases of illness in 2016. Information on the sources and transmission pathways of human cryptosporidiosis results mainly from outbreak investigations. A systematic review and a meta-analysis of case-control and cohort studies were performed to determine the main risk factors associated with sporadic cryptosporidiosis. Suitable scientific articles were identified through a systematic literature search and subjected to a methodological quality assessment. From each study, odds ratio (OR) measures were extracted or calculated, as well as study characteristics such as population type, design, type of model and risk factor hierarchy. Mixed-effects meta-analysis models were adjusted by population type to appropriate data partitions. From 1985 identified references, the quality assessment stage was passed by 57 cohort and case-control studies focusing on sporadic cryptosporidiosis. The eligible studies were conducted between 1983 and 2016 and provided 568 OR categorized for meta-analysis. This meta-analysis identified travel, immunocompromising conditions, contact with infected humans, waterborne transmission (contact with recreational waters, wastewater, and consumption of untreated drinking water), contact with animals and food consumption as the relevant risk factors for sporadic cryptosporidiosis. With regards to food exposures, consumption of meat, dairy products (raw milk) and dishes consumed outside home were found significantly associated with cryptosporidiosis. The consumption of poorly washed fruits and vegetables significantly increases ORs. This meta-analysis reveals that some potential sources of Cryptosporidium such as shellfish or vegetables are under-investigated. Future case-control studies for sporadic cryptosporidiosis should include population at risk, and investigate other potential sources in relation to the genotype and the subtype of Cryptosporidium spp.
- Risk factors for sporadic giardiasis: a systematic review and meta-analysis: meta-analysis of risk factors associated with sporadic giardiasisPublication . Thébault, Anne; Favennec, Loic; Kooh, Pauline; Cadavez, Vasco; Gonzales-Barron, Ursula; Villena, IsabelleGiardia duodenalis is an important source of gastroenteritis worldwide. Endemic cases have been described in developing and industrialized countries. We analyzed risk factors for sporadic giardiasis by a systematic review and a meta-analysis of the literature. From 72 studies, contact with an infected person, lack of personal hygiene, and attending a child daycare center were identified as risk factors in children and adults. Feco-oral transmission was significantly associated with exposure to human sewage/waste water, untreated drinking water and recreational waters. Travel abroad was a risk factor in industrialized countries. No handwashing before eating or preparing food, eating unwashed vegetables, or composite food were significant risk factors. Breastfeeding was a protective factor in developing countries. Interestingly, contact with pets was found as a significant risk factor in children in this meta-analysis. This could be explored in future studies with the comparison of the Giardia assemblage isolated from humans and pets. In the future, it would be interesting to investigate more precisely the type of water, vegetable, and whenever possible the method of preparation/treatment. Environmental and epidemiological investigations of specific risk factors by assemblages and types of Giardia spp. should be further studied. Finally, host factors in relationship with the severity and sequelae of giardiasis deserve future research.
- Risk factors for sporadic hepatitis A infection: a systematic review and meta-analysisPublication . Thébault, Anne; Roque-Afonso, Anne Marie; Kooh, Pauline; Cadavez, Vasco; Gonzales-Barron, Ursula; Pavio, NicoleHepatitis 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 hepatitis E infection: a systematic review and meta-analysisPublication . Pavio, Nicole; Kooh, Pauline; Cadavez, Vasco; Gonzales-Barron, Ursula; Thébault, AnneHepatitis E virus (HEV) is one of the main causes of viral hepatitis infection worldwide. Sources of contamination can vary greatly according to geographical regions and HEV genotypes. HEV is endemic and responsible for large waterborne epidemics involving human HEV-1 or HEV-2 genotypes in regions with limited sanitation, in contrast to industrialized countries, where HEV is mainly a foodborne zoonosis involving HEV-3 and HEV-4 zoonotic genotypes. Limited data on HEV source attribution are available, and all possible sources and transmission pathways of HEV are not fully identified. A systematic review and a meta-analysis of case-control and cohort studies (including transversal studies) were performed to determine the main risk factors associated with sporadic hepatitis E infection. Suitable scientific articles were identified through a systematic literature search and subjected to a methodological quality assessment. From each study, odds-ratio (OR) measures were extracted/calculated, as well as study characteristics such as population type, design, and risk factor hierarchy. Mixed-effects meta-analyses models were adjusted by population type to appropriate data partitions. Seventy-seven cohort and case-control studies conducted between 1986 and 2016 and investigating risk factors in mixed population, susceptible population, and pregnant women, were included in this meta-analysis. Hepatitis E cases were defined with serological exams and differentiated whenever the serological exam is associated or not with symptoms. This meta-analysis identified the parenteral pathway (blood transfusion, tattooing or IV injection, dialysis or hemodialysis), and routes of infection related to contaminated water, animal contact (occupational exposure) and consumption of foods as relevant risk factors for hepatitis E infection. With regards to the role of food, as suspected and sometimes proven in several studies, pig meat, pork sausages, and game meat are identified as significant risk factors for HEV, in particular undercooked pig meat, or meat preparations containing pig liver. In addition, consumption of shellfish (oysters and mussels), in which HEV can accumulate when water is environmentally contaminated (from animal or human origin), is also associated with the detection of anti-HEV antibodies. The results of this meta-analysis show that symptomatic and infected cases share the most explainable risk factors, and are in agreement with recent studies conducted in Europe. This meta-analysis reveals that some sources such as consumption of insufficiently treated water, shellfish, or vegetables are under-investigated. Future case-control studies should include population at risk but under-investigated, such as transplant recipients, pregnant women and children, and investigate other potential sources of HEV.
- Risk factors for sporadic infections caused by Shiga toxin-producing Escherichia coli: a systematic review and meta-analysisPublication . Augustin, Jean Christophe; Kooh, Pauline; Mughini-Gras, Lapo; Guillier, Laurent; Thébault, Anne; Audiat-Perrin, Frédérique; Cadavez, Vasco; Gonzales-Barron, Ursula; Sanaa, MoezShiga 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 listeriosis: a systematic review and meta-analysisPublication . Leclercq, Alexandre; Kooh, Pauline; Augustin, Jean Christophe; Guillier, Laurent; Thébault, Anne; Cadavez, Vasco; Gonzales-Barron, Ursula; Sanaa, MoezListeriosis is a major public health concern associated with high hospitalization and mortality rates. The objective of this work was to summarize evidence on the associations between risk factors and sporadic cases by meta-analysing outcomes from currently published case-control studies. Suitable scientific articles were identified through systematic literature search, and subjected to a methodological quality assessment. From each study, odds-ratio (OR) measures as well as study characteristics such as population type, design, type of model and risk factor hierarchy were extracted. Mixed-effects meta-analysis models were adjusted by population type to appropriate data partitions. Twelve primary studies investigating sporadic listeriosis conducted between 1985 and 2013 passed through a quality assessment stage. These studies provided 226 OR considered for meta-analysis. According to the meta-analysis, the main risk factor for acquiring listeriosis is suffering from an immunocompromising disease. In relation to the food exposures, this meta-analysis confirmed known risk factors such as consumption of RTE dairy, seafood and processed meat and underlined new food vehicles as fruits and vegetables, recently involved in outbreaks. There were not enough data to appraise travel, animal-contact and person-to-person as transmission pathways for listeriosis. These results will allow refining the case-control studies in the aim of improving risk factors characterisation for listeriosis in the susceptible population.
- Risk factors for sporadic norovirus infection: a systematic review and meta-analysisPublication . Thébault, Anne; David, Julie; Kooh, Pauline; Cadavez, Vasco; Gonzales-Barron, Ursula; Pavio, NicoleNorovirus is responsible for 20% of acute gastroenteritis worldwide. The fecal-oral route of transmission is known, but we proposed a first attempt to identify the relative importance of different sources and vehicles for sporadic cases using meta-analysis models. Case-control and cohort/cross-sectional studies were systematically reviewed and analyzed to assess the main risk factors associated with sporadic norovirus infections. Suitable 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 risk factor categories. The quality assessment stage led to include 14 primary studies conducted between 1993 and 2014. From these, eight studies investigated exposures in children/infants, and eight concerned the mixed population. The meta-analysis confirmed the oro-fecal route for norovirus infections, with the person-to-person transmission (pooled OR=3.002; 95% CI: [2.502 -3.060] in mixed population), and the lack of personal hygiene (pooled OR=2.329; 95% CI: [1.048 -5.169]). The meta-analysis also enlightened the role of indirect transmission through the environment with pathways like untreated drinking water (mixed population), with a pooled OR=2.680 (95% CI: [1.081-6.643]) and farm environment (children population). Indirect transmission also involved the food pathway, which was finally found significant with consumption of seafood (mixed population) (pooled OR=2.270; 95% CI: [1.299-3.968]) and composite food (eating outside/uncooked mixed and young population) (pooled OR=4.541; 95% CI: [3.461-5.958]). These results are coherent with the findings from studies on outbreaks. However, a too broad definition of exposure factors limited the interpretation of results, as occurred with the seafood pathways that combined fish and shellfish. Other factors such as consumption of Food-handled products or the type of drinking water deserveE to be better investigated. Furthermore, better harmonization in case definition and appropriate case-control or cross-sectional studies would allow better addressing sporadic cases risk factors, especially for susceptible populations, such as children, elderly or immunosuppressed persons.
- Risk factors for sporadic salmonellosis: a systematic review and meta-analysisPublication . Guillier, Laurent; Thébault, Anne; Fravalo, Philippe; Mughini-Gras, Lapo; Jourdan-da Silva, Nathalie; David, Julie; Kooh, Pauline; Cadavez, Vasco; Gonzales-Barron, UrsulaNon-typhoidal Salmonella is an important causative agent of diarrheal illness worldwide. A systematic review and meta-analysis of case-control studies were performed to determine the main risk factors associated with sporadic salmonellosis. Suitable scientific articles published up to 2017 were identified through a systematic literature search and subject to methodological quality assessment. From each study, odds ratios (OR) were extracted or calculated, as well as study characteristics such as population type, design, type of model used and risk factor categorization. Mixed-effects meta-analytical models were adjusted by population type to appropriate data partitions. From 3858 identified references, the quality assessment stage was passed by 62 case-control studies focusing on sporadic salmonellosis which provided 1154 ORs for meta-analysis. The meta-analysis identified host-specifics factors, travel, environmental, animal and food exposures as significant risk factors of salmonellosis in the mixed population. For the mixed population, foods significantly associated with salmonellosis were eggs and egg products, composite foods, and meat (pork, red meats other than beef and poultry meats). In the child population, the main risk factors were found for person-to-person transmission, recent use of gastric anti-acids or antibiotics, contact with pets and farm animals, environmental, and food vehicles. Breastfeeding was found to be a protective factor for children. The food vehicles identified in children comprised dairy (milk formula), produce, meat and eggs products. Untreated drinking water was a risk factor for the children and mixed population. The result of the meta-analysis conducted at the international level is very important in the context of increasing international trade in foodstuffs and changes in food consumption patterns.
- Risk factors for sporadic Yersinia enterocolitica infections: a systematic review and meta-analysisPublication . Guillier, Laurent; Fravalo, Philippe; Leclercq, Alexandre; Thébault, Anne; Kooh, Pauline; Cadavez, Vasco; Gonzales-Barron, UrsulaYersinia enterocolotica is an important causative agent of diarrheal illness. A systematic review and meta-analysis of case-control studies were performed to determine the main risk factors associated with sporadic Y. enterocolitica infections. Suitable scientific articles published between 1987 and 2017 were identified through a systematic literature search and subject to methodological quality assessment. From each study, odds ratios (OR) were extracted or calculated, as well as study characteristics such as population type, design, type of model used and risk factor categorization. Mixed-effects meta-analytical models were adjusted by population type to appropriate data partitions. From 807 identified references, the quality assessment stage was passed by 14 case-control studies focusing on sporadic Y. enterocolitica infections which provided 165 ORs for meta-analysis. All studies considered Y. enterocolitica as the cause of sporadic infections and are mainly located in Europe. The meta-analysis identified host-specifics factors, animal and food exposures as significant risk factors. The meta-analysis confirms the predominant role of the pig reservoir. The occupational contact with pigs and the consumption of pork meat are significantly associated with sporadic Y. enterocolitica infections occurrence. The consumption of raw or undercooked pork meat is also a very important risk factor. Untreated drinking water was also identified as risk factor. Further studies with other enteropathogenic Yersinia species, especially Y. pseudotuberculosis, and/or from other continents would help to refine conclusions of the meta-analysis of the risk factors of yersiniosis.