Figure 4. Distribution of anti-HEV IgG in blood donors according to age group. A) in January 2011; B) in March 2012; C) groups 2011 and 2012 combined. doi:10.1371/journal.pone.0048125.g004 methods we found a very similar result for the two tests. If this result was related to the genotype of the circulating HEV or to a specific immune status in the Burkinabe population remained to be assessed. The seroprevalence of anti-HEV IgG among Ouagadougou blood donors (19.1%, CI95 [13–24%]) was higher than those reported for Italy (2.6%), Germany (2.1%) and California (1.2%) but was close to that found in the south of France (16.6%) [47–49]. The seroprevalence of HEV found in this study was similar to those observed in Tunisia (22%), Burundi (14%), Singapore (14.5%) and South Africa (15.3%) [50–52]. The anti-HEV seroprevalence in our group of pregnant women (11.6%, CI95 [7.1–16.2%]) from the Burkina Faso plateau region of which Ouagadougou is the center, was lower than those found in most of these other countries but was comparable to those found in pregnant women in Tunisia (12.1%) and Turkey (12.6%) [53,54]. Low prevalences (1–5%) have been reported for countries with low HEV endemicity, such as the United States or those in Hepatitis A and E Viruses in Ouagadougou Northern Europe [55,13]. The HEV seroprevalence among pregnant women (11.6%) was slightly lower than that of either men or women blood donors (17.6% and 23.4%, respectively). Other studies of pregnant women reported similar patterns in Gabon (10–20%). These findings may be related to differences in socioeconomic status of the pregnant women, but we did not record any such data in our study [56]. We found the highest anti- HEV seroprevalence in the ,25 years of age group (Figure 4C), which has been reported to be at high risk for HEV infection worldwide [13,57,58]. Nevertheless, in endemic areas, childhood hepatitis E infections are frequent than childhood hepatitis A infections. HEV is an infection of young adults, with the peak incidence between the ages of 15 and 35 years [59,60]. Our study was limited to this age class and we did not examine the seroprevalence in children. As HEV infection is particularly serious during pregnancy, our findings indicate that HEV awareness needs to be increased. The distribution of IgG anti- HEV seropositivity among blood donors according to age group showed a significant increase for the age group .36 years, from about 0% in 2011 to 26.4% in 2012. This absence found in the first sampling period in 2011 was quite unusual but could be due to sampling hazard or to HEV being introduced only recently. The 2012 data were more in accordance with those obtained in China by Li et al. in 2006 [61], showing that the seroprevalence of HEV could be related to both age and the level of endemicity or dietary exposure factors. Recent studies in France indicate that HEV higher seropreva- lence may be associated with dietary habits, and particularly with consumption of pork or rabbit meat [14,16,20,49]. Despite presence of rabbit breeding in rural areas of Bukina-Faso, little is known about rabbit meat consumption in large cities. In Ouagadougou, pork from locally-bred pigs is found in local fast- foods (grilled pork vending outlets) and is widely consumed by the population. As shown recently, the nature of processing affects the prevalence of HEV in the pork production chain in Europe [62]. Thus, complementary studies addressing eating habits and the serology of exposed population would be the logical continuation of the present study. Several studies have shown that low socioeconomic status, poor hygiene, lack of sewers, and un- derdeveloped health care facilities constitute the main transmission risk factors for HAV and HEV [32,63,64]. Conclusions Despite being limited to a small subset of the Ouagadougou population, our findings emphasize the need to establish a national HAV and HEV surveillance program consisting. This program should include additional sero-epidemiological surveys to track changes in the epidemiology of these viruses, and especially factors for their persistence, and the role of eating habits and food processing methods in the spread of these infections. Data from such a program could be used as the basis for designing an HAV vaccination campaign and to enhance HEV surveillance. In addition, HEV infection should not be considered rare and its presence should be actively investigated, especially in pregnant women given that HEV infection adds significant health risks to pregnancy. Additional studies are needed to detail the incidence and severity of this illness in pregnant women in Burkina Faso. Finally, addressing the public health problems associated with the enteric transmission of viral hepatitis in developing countries will require implementing stronger measures to prevent fecal contamination of food and water. PLOS ONE | www.plosone.org 5 October 2012 | Volume 7 | Issue 10 | e48125