Browsing by Author "Pavio, Nicole"
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- 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 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.