These cases were attributed to sexually transmitted HAV and justified some outbreaks among MSM that have been described in Denmark, Sweden, the United Kingdom and the United States. Since the 1980s, when an important decrease in HA incidence due to socio-economic improvements was evident, a peak in the incidence of HAV was noticed in males from 20 to 39 years old. Bearing in mind that vaccinated travellers still represent a small amount, it is crucial to promote this prophylaxis measure among physicians and this at-risk population. Ĭonsidering prophylaxis for travellers in several countries, many recommendations and guidelines have been issued emphasising the importance of a correct information and prophylaxis for this at-risk group. įew prevalence studies with contrasting and inconclusive data have been published regarding anti-HAV positivity and history of travel. The risk increases among young children visiting friends and relatives that accounted for a large proportion of cases and should be prioritised for vaccination. ![]() Ī population-based study performed showed that the highest risk was associated with travel to East Africa followed by the Middle East, India and neighbouring countries. Īlthough the risk of infection may have slightly decreased in recent years, the incidence rate for non-protected travellers is estimated to be 3 cases per 1000 travellers per month of stay in developing countries. The risk is varied and depends on the endemicity of visited countries and on the adherence of hygienic practices. Travel is still one of the most important risk factors for HAV infection despite the improvement of socio-economic level considering the last decades. In terms of HA endemicity, it is important to point out that exportation of food that cannot be sterilised, from countries of high endemicity to areas with low rates of infection, is a potentially important source of infection. Countries with intermediate levels of HA present increased numbers of susceptible adults and, occasionally, large outbreaks. ![]() In contrast, in developed countries with adequate sanitation and infrastructure, infection rates are low, and outbreaks are infrequent as long as the disease is not introduced into the population from an external source. Therefore, in these areas outbreaks are not frequent, and children develop immunity without ever being symptomatic. In developing countries, with poor sanitary infrastructure, there are high infection rates occurring in childhood, and HA is endemic. ![]() Maternal-foetal transmission has not been described.Īccording to endemicity of hepatitis A (HA) disease, it can occur in three distinct ways. ![]() Other modes of HAV transmission are due to blood transfusion and use of illicit drugs. HAV infection due to consumption of contaminated food or water includes ingesting raw or undercooked foods, namely, shellfish and vegetables, or consumption of meals contaminated by infected food handlers. Regarding person to person contact, the transmission can occur within households, residential institutions and daycare centres, among military personnel and during sexual intercourse. Less commonly, the transmission occurs due to consumption of contaminated food or water. HAV is usually transmitted by the faecal-oral route: primarily through close personal contact or by oral intake after faecal contamination of skin or mucous membranes.
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