Hepatitis A is a viral disease. It affects the liver and is transmitted through contaminated food and drink, or even through direct contact with infected people. It is an acute infectious disease caused by an RNA virus belonging to the genus Heparnavirus of the Picornaviridae family (HAV). Together with other viruses such as HBV which causes hepatitis B and HCV which causes hepatitis C, it attacks the liver cells.
Health authorities believe that hepatitis A is widespread throughout the world, and that it occurs from time to time also in an epidemic, and not only sporadic, form. It is transmitted more easily where there are poor sanitary conditions, such as in developing countries. But also in Southern Italy, where it is endemic. It generally spreads more rapidly among children, and is often asymptomatic. Many adults today are unaware that they have been infected with it. It is believed to be a disease that does not become chronic, unlike hepatitis B and C. Hepatitis A: everything you need to know
To get to know everything you need to know in a nutshell, the Ministry of Health has created a series of Faqs, in which it offers all the answers you would like to have when you don’t know what you are or might have to do with. What is hepatitis A
Hepatitis A is an acute infectious disease affecting the liver. It is caused by an RNA virus. How hepatitis A
is transmitted Infection is generally transmitted via the fecal-oral route, through the ingestion of contaminated food or water. But also through contact with infected people. In fact, human-to-human transmission through direct contact is frequent. An infected subject eliminates the virus, and consequently is contagious, from 7-10 days before the onset of symptoms to a week later.Symptoms of hepatitis A
The disease often develops asymptomatically, especially when the infection is contracted in childhood. The symptoms, when present, appear after an incubation period of 15-50 days: there may be inappetence, general malaise, fever, nausea and vomiting. After a few days, jaundice appears, when the skin becomes yellow in color, as do the sclerae (the white part of the eye) and mucous membranes. This is due to the increased concentration of bilirubin in the blood as a result of impaired liver function.
The disease generally has a benign evolution, albeit with a prolonged course (lasts from 2 to 10 weeks). Sometimes, especially in adult subjects suffering from concomitant pathologies, severe forms and fulminant forms due to hepatic insufficiency have been observed. How widespread is hepatitis A
Hepatitis A is present throughout the world in both sporadic and epidemic forms. Each year there are an estimated 1.4 million cases of hepatitis A (HAV), with a higher frequency in the countries of the southern hemisphere. But it is also widespread in Southern Italy, often caused by the consumption of (raw) seafood or other contaminated foods.
Traditionally 3 geographic categories of endemicity related to the prevalence of HAV are described:
– Highly endemic areas, which have poor sanitation conditions;
– Areas with intermediate endemicity, which include developing countries with varying sanitation conditions;
– Low endemic areas, which include industrialized countries with good sanitary conditions.
In countries where the infection is endemic, children are predominantly affected. Generally, even though they contract the infection, the little ones do not show evident symptoms. Since the disease induces permanent immunity, in these areas, adolescents and adults are immune and constitute a barrier to the spread of the infection, thus hindering the occurrence of epidemics.
In countries with intermediate and low endemicity, the infection mainly affects adolescents and adults, who, not having contracted the disease in childhood, are not immune; the population is therefore susceptible and epidemic outbreaks can occur.
Italy, thanks to the improvements in hygienic and socio-economic conditions, is a country with medium-low endemicity. The incidence of the disease shows a decreasing trend, falling below the threshold of 1 case per 100,000 inhabitants.
However, over the years, epidemic outbreaks have occurred linked to the consumption of polluted foods (in 1992, 1994, 1997, 2013) and / or to risk behaviors (2016). What are the risk factors for hepatitis A
Several factors can intervene in the transmission of the infection. The most common risk factors are:
– Consumption of polluted foods, such as raw or insufficiently cooked seafood, berries, vegetables.
– Use of contaminated water.
– Poor hygiene, especially when preparing food.
– Travel to endemic areas.
– Close contact with an infected person.
– Sexual transmission (especially with oral-genital practices). How
contagion can be avoided Contagion can be avoided by respecting the hygiene rules generally used for the prevention of fecal-oral diseases:
– Do not consume raw seafood. Cooking is the only effective measure to eliminate or inactivate the hepatitis A virus from bivalve molluscs or other contaminated fresh produce such as fruit and vegetables.
– Wash the vegetables thoroughly before consuming them.
– Wash and peel the fruit.
– Do not drink well water.
– Carefully take care of personal hygiene, especially of the hands: wash your hands after using the bathroom, after changing a diaper, before preparing food, before eating, etc.
– Be scrupulously clean when handling food and drinks.
– Consult the vaccination centers present in the region, authorized for international prophylaxis, for advice on vaccinations before leaving for areas with poor sanitation or endemic conditions.
– In case of stay in countries with poor sanitary conditions, eat only cooked foods, in particular vegetables and seafood, drink only bottled water and do not consume ice (if you do not know the exact origin of the water with which it was prepared).
– Practicing safe sexual relations. Which foods are most at risk of transmitting hepatitis A
By studying the origin of outbreaks, the European Food Safety Agency (EFSA) and the European Center for Disease Control (ECDC) have identified multiple types of foods that can be vehicles for infection. Among these, the most frequently involved are: fish and fish-based products, crustaceans, molluscs and products containing molluscs, vegetables, juices, dried tomatoes, berries, strawberries, frozen mixed berries. How plant foods are contaminated with the hepatitis A virus
The most frequent source of contamination of plants is constituted by contaminated water used for irrigation and / or fertigation. Through water, viruses are deposited preferably on the external surface of plants and it is not yet clear whether there is an internalization mechanism. At the moment, scientific data is available only for onions which demonstrate, through experimental tests, the transport of viruses through the roots. Washing with drinking water is effective in reducing viral concentration
. Washing can reduce the viral concentration but not eliminate it. Washing is therefore not sufficient to protect against the infection of the virus. What treatments guarantee the elimination of the virus
The hepatitis A virus survives in low temperatures and resists freezing. Instead, it is sensitive to heat. The virus is inactivated with treatment at 60 ° C for about 1 hour, boiling for 5 minutes, with dry heat (180 ° C for 1 hour), with treatment in an autoclave, ultraviolet radiation, formalin and chlorine. There is a vaccine against hepatitis A
Yes, there is an effective and well tolerated vaccine. The vaccine is prepared using virus strains grown on diploid cells (belonging to the fibroblast line) and inactivated with formaldehyde. The vaccine must be stored in the refrigerator and is administered intramuscularly.
Protection is achieved 14-21 days after the first dose; a second dose 6/12 months after the first prolongs its protective efficacy, providing protection for a period of 10-20 years. In Italy you can find both the monovalent vaccine, in pediatric and adult formulations, and the combined vaccine (associated with hepatitis B vaccine).
Vaccination is recommended in subjects at risk:
– subjects who live in places where there are epidemic outbreaks;
– subjects who have to go for vacation or work to countries where the disease is endemic (Central or South America, Mexico, Asia-Japan excluded, Africa and Eastern Europe);
– family members, or those who have close contacts with people suffering from the disease;
– subjects suffering from chronic liver disease;
– substance consumers;
– subjects who work in research laboratories where contagion is possible;
– males having sex with males (MSM) What to do if you have been exposed to risk of hepatitis A
If you have been exposed to the risk of infection with the hepatitis A virus, both active prophylaxis (with vaccination) can be implemented which is passive (through the administration of gamma globulin -Ig).
The hepatitis A vaccine is effective in preventing disease even after contact with the virus, as long as it is given within 14 days after exposure.
Passive protection can be obtained with the use of Ig, prepared from plasma pools of adult subjects.
The efficacy of Ig, especially if administered more than 14 days after exposure to risk, is controversial; often their action manifests itself, not preventing the infection from occurring, but making it more mild and sub-clinical.
