Given the importance of hepatitis in international communities, understanding the exposure rate in some careers would not only contribute to global prevention, but also highlight their importance as possible risk factors. In the current study, for the first time, the seroprevalence of hepatitis E and A viruses was investigated among Shiraz municipal district street sweepers, the largest city in the south of Iran.
Previous studies reported that the seroprevalence of HAV among adults (around 30 years old) in Iran and Fars province was over 82.6% (19) and 99% (6), respectively, which was much similar to our study that revealed a 100% rate among street sweepers.
As the second step, this study showed that 16.1% of the investigated cases were posetive for anti-HEV Ab. The primary idea has suspected a higher rate, more significant than the normal population, due to common route of transmission (fecal-oral) and exposure of this particular group to sewage, contaminated water, and poor occupational hygiene, especially when eating and drinking at work. A study carried out by Asaei et al. in Shiraz reported the sero-prevalence of 13.4% for total anti-HEV among the healthy population (20). Recently, it has been reported that 10.4% (26/151) of HIV infected patients in Fars Province were positive for anti-HEV Ab(20).
Sweeping and collecting garbage are among the careers in which the spread of oral-fecal infection is more common. A recent study in India indicated a higher concentration of fecal pollution, as marked by E.coli detection, at the end of the daily work activities (21). Another study on sweepers has indicated that they are at high risk of infection with Toxocara infection. Therefore, oral-fecal contamination by several microorganisms circulating among humans in this way is common in the mentioned group (22). In Egypt, parasitic infestations including Entameba histolytica and Hymenolepis nana were also detected more significantly in stool analysis street sweepers than university employees (23). The findings of Kretchy et al. revealed that solid waste collectors should be provided with proper protective measures and sanitation facilities, and they should be trained on hygienic behaviors to prevent oral-fecal contamination by food/water-borne contaminants (24) .
In the case of HEV, few studies have been evaluated to determine its sero-prevalence among street sweepers or waste collectors. In 2003, Vadiya et al. showed that 56.5% of sewage workers were anti-HEV IgG positive; this is significantly higher exposure rate than the relevant normal population. Therefore, a career with direct contact with sewage or sewage-contaminated materials can be considered a risk factor (25). In addition, a study by Farshadpour et al. has shown a significant difference between the prevalence of HEV antibodies and the living place (26). Meanwhile, the study of Saffar et al. in 2009 revealed that the most significant relationship between seroprevalence of this virus and living place was in rural areas (27). In our study, 16.4% of street sweepers lived in rural areas, and 14.3% of those who lived in rural areas were HEV seropositive. However, no significant association was found.
In a noble finding, the study revealed that 6.7% of seropositive and 8.2% of seronegative individuals were aware of hepatitis vaccination although no significant association was reported. On the other hand, 0.6% of seronegative and none of the seropositive street sweepers were aware of the treatment of hepatitis with no statistically significant association (20). Vaidya and Asaei's studies revealed that the seroprevalence of anti-HEV IgG is directly related to age in sewage collectors, which is in accordance with our results. The seroprevalence of anti-HEV IgG in street sweepers was 4.5% in the age range of 20 to 30 years, 10.1% in 31 to 40 years, 17.4% in 41 to 50 years, and 36.7% in sweepers over 50 years, which indicates a significant relationship between aging and increase in anti-HEV seropositivity among the sweepers (12, 24) .
Also, in Vaidya’s study, a significant increase of anti-HEV IgG was reported in those in contact with urban garbage for more than 5 years (67.6%) compared to those who had worked for less than 5 years (38.9%)(25). In the present study, the anti-HEV IgG seroprevalence was 16.9% among people with 5 or over 5 years of working, while this figure was 13% in people with less working duration; however, no statistically significant relationship was observed between the HEV seroprevalence and the working duration.
Although sanitation such as hand washing has been recommended in most articles as an effective way for public health (28, 29), we did not find a relationship between the seroprevalence of HEV and hand washing. The present study also confirmed that 17.1% of street sweepers who washed their hands with soap and water and 15.8% of those who used only water to wash their hands and faces were positive for anti-HEV IgG. However, it is clearly indicated that sanitation status makes this population more vulnerable to infection by food/waterborne microorganisms, as demonstrated previously(24).
Also, 16.7% of street sweepers who washed their hands and face more than 2 times during and after work and 18.3% of those who did so fewer than 2 times were positive, respectively. However, no significant relationship was found between the sero-prevalence of anti-HEV and the number and method of washing hands and faces. On the other hand, Dahiya et al. pointed out the importance of using mask to prevent HEV infection which is transmitted through the mouth (30). In the present study, 14.9% of street sweepers who always used mask during sweeping and 19.4% of those who rarely did so were HEV seropositive. However, no significant difference was found between the seroprevalence of anti-HEV and wearing face mask .
Tha absence of molecular assays to find the status of virus genome among the individuals and non-sweeper men in the control group was a limitation of the present study. In conclusion, although our results showed that 100% and 16.1% of street sweepers were positive for anti-HAV and HEV IgG Ab respectively, which was slightly higher than the normal population. However, it does not seem that garbage collecting/sweeping career is significant risk factors of HAV and HEV infection.