Hepatitis A

Hepatitis A virus, HAV, is an envelope-less RNA virus classified as picornavirus. It was first isolated in 1979. Humans are its only natural host, although several nonhuman primates have been infected under laboratory conditions.

HAV is acquired orally (through fecal-oral transmission), when an uninfected person ingests food or water contaminated with the feces of an infected person, and replicates in the liver. Waterborne outbreaks, although rare, are usually associated with contaminated or inadequately treated water.
After 10-12 days, the virus is present in the blood and is excreted through the biliary system in the feces. Peak titers occur during the two weeks before the onset of illness. Although the virus is present in serum, its concentration is several orders of magnitude lower than in feces. Most infected people no longer excrete virus in the feces by the third week of illness. Children may excrete the virus longer than adults.
The virus can also be transmitted through close physical contact (such as oral-anal sex) with an infected person, while casual contact between people does not spread the virus.
Transmission also occurs indirectly: in fact, there have been many cases of transmission through ingestion of contaminated water or food, especially raw food such as shellfish.

Overall, WHO estimated that 7134 people died of hepatitis A worldwide in 2016 (accounting for 0.5% of mortality due to viral hepatitis). Hepatitis A is widespread throughout the world. In some countries, poor sanitation, malfunctioning sewage systems, and difficult access to potable water are among the main causes of infection. In recent years, there has been an increase in symptomatic transmission of the virus in Western countries and industrialized areas. HAV is common in areas with inadequate sanitation and limited access to clean water. In highly endemic areas (such as parts of Africa and Asia), a large percentage of adults in the population are immune to HAV, and outbreaks of hepatitis A are rare. In areas of intermediate endemicity (such as Central and South America, Eastern Europe, and parts of Asia), childhood transmission is less frequent, more adolescents and adults are susceptible to infection, and outbreaks are more likely. In areas of low endemicity (such as the United States and Western Europe), infection is less common, but the disease occurs among people in high-risk groups, travelers, and as community-based outbreaks. Hepatitis A is among the most common vaccine-preventable infections acquired during travel. Travel-related cases of hepatitis A may occur more for those who live in or visit rural areas, or frequently eat or drink in poor hygiene and overcrowded environments, such as large capital cities.

The incubation period of hepatitis A is about 28 days, but can vary between 15 and 50 days. The clinical course of acute hepatitis A is indistinguishable from that of other types of acute viral hepatitis. The disease typically has a sudden onset of fever, malaise, anorexia, nausea, abdominal discomfort, dark urine, and jaundice. Clinical illness usually lasts no longer than 2 months, although 10% to 15% of people have prolonged or relapsing signs and symptoms for up to 6 months. The virus may be excreted during a relapse. The likelihood of symptomatic illness from HAV infection is directly related to age. In children younger than 6 years of age, most (70%) infections are asymptomatic. In older children and adults, infection is usually symptomatic, with jaundice occurring in more than 70% of patients. Serious clinical manifestations of hepatitis A infection are rare; however, atypical complications may occur, including extrahepatic immunologic, neurologic, hematologic, pancreatic, and renal manifestations. Relapsing hepatitis, cholestatic hepatitis A, autoimmune hepatitis triggering hepatitis A, sub-fulminant hepatitis, and fulminant hepatitis have also been reported. Fulminant hepatitis is the most serious rare complication, with mortality estimates of up to 80%. In the pre-vaccine era, fulminant hepatitis A caused about 100 deaths per year in the United States. The mortality rate for hepatitis A among people of all ages with reported cases was about 0.3% but may have been higher among older people (about 2% among people aged 40 years and older). The most recent case fatality estimates range from 0.3% -0.6% for all ages and up to 1.8% among adults aged> 50 years. Vaccination of high-risk groups and public health measures have significantly reduced the number of overall hepatitis A and fulminant HAV cases. However, hepatitis A causes substantial morbidity.

Blood tests with HAV-specific immunoglobulin G (IgM) antibodies or PCR tests to detect virus RNA are required to confirm the diagnosis of Hepatitis A infection.

There is no specific treatment for hepatitis A. Recovery from symptoms after infection can be slow and may take several weeks.
Medical care aims to maintain clinical well-being, including replacement of fluids lost due to vomiting and diarrhea. Then care is based on treating symptoms and supporting vital functions.

To counter the planetary spread of the hepatitis A virus and possible contagion, the safest course is vaccination. Such vaccination can be carried out on both adults and children. All persons traveling for any purpose, frequency or duration to countries with high or intermediate HAV endemicity should be vaccinated. Many medical experts in International and Travel Medicine believe that all travelers should be educated about the risks of hepatitis A and have the opportunity to vaccinate. In addition to vaccination, dietary behavior can also help reduce the risk for HAV, along with proper hand washing before food handling. Improved sanitation, food safety, and immunization are THE most effective cornerstones for countering hepatitis A infection.

Raw food
Raw food should generally be avoided. Raw fruits or vegetables may be safe if you can peel them yourself or wash them in safe (bottled or disinfected) water. Avoid cut fruit or vegetable dishes. Also avoid fresh sauces or other condiments made from raw fruits or vegetables. Raw meat or seafood can be at high risk of contamination.

Street food
If you consume street food, apply the same rules as other foods; for example, prefer foods cooked directly at the moment.

Tap water
In most low-resource countries, tap water probably should not be drunk, even in cities. This includes ingesting water while showering or brushing your teeth. Brushing teeth with bottled water may be advisable in some areas. Tap water can be disinfected by boiling, filtering or chemically treating it, such as with specific chlorine products. Ice, which was probably made with tap water, should also be avoided.

Freshly squeezed juice
If you washed the fruit in drinking water and squeezed the juice yourself, it can be considered safe. Juice squeezed by unknown hands can be risky. The same goes for popsicles and other treats made from freshly squeezed juice.

A key recommendation for all travelers to high-risk areas is to avoid consumption of raw food and drinks with ice or unpasteurized milk.