By Dr Eddy Bajrovic*
Hear the words ‘hepatitis’ and ‘international travel’ together and it’s likely Hepatitis A is being discussed.
Hep A is not only spread directly from person to person, but also through food, beverages and everyday items that have been contaminated with the virus, making it one of the most persistent risks for travellers visiting any developing countries – even those staying for just a couple of weeks in better quality accommodation.
In Australia, almost all cases of Hep A are among returned travellers or from outbreaks linked to imported foods, such as frozen berries.
On the other hand, the B and C strains of hepatitis, which are transmitted in infected blood and body fluids, are common here. For Aussie travellers, infection from hepatitis B, C or the rarer fourth ‘D’ strain are usually the result of unprotected sex with an infected person, needle sharing, or via contaminated equipment used during an emergency medical procedure, acupuncture, body piercing or tattooing.
But, travellers who visit Travelvax Australia’s clinics are often surprised to hear that there’s a fifth strain of the liver disease – hepatitis E.
Like hepatitis A, Hep E is also spread by the faecal-oral route, usually when sewage contaminates water or food, particularly raw shellfish. Large-scale epidemics periodically occur in Asia, the Middle East, Africa, and Central America, especially after floods and other natural disasters.
‘E’ strain may be much more common
Hep E could be far more pervasive than previously thought, a recent US study suggests.
Researchers at the Johns Hopkins Bloomberg School of Public Health in Baltimore used a new-generation hepatitis E ‘assay’ or test to retest 1000 blood samples originally taken in the year 2000 for a study into Hep E in rural Bangladesh. Back then the assays used were far less sensitive and detected the virus in only 27% of the 1000 volunteers.
However, a highly sensitive assay developed in China was used to again test the same 1000 samples recently and found 47% had antibodies to Hep E – almost double the original figure.
The World Health Organisation (WHO) had estimated the number of new Hep E infections worldwide each year at 20 million, with around 1-in-100 resulting in death.
However, given the US study, it seems the worldwide incidence of the virus may have been significantly underestimated.
Pregnant woman at highest risk
One group is far more susceptible to severe illness and death from Hep E than any other – pregnant women.
The E strain is fatal for between 15-30% of mothers-to-be in their third trimester. Tragically, even if the mother survives, it’s common for the foetus to die.
It’s not known why pregnant women are at higher risk of severe outcomes.
The high mortality rate is not seen in the other hepatitis viruses and at least one study has suggested that a fall in the number of protective T-cells that occurs during pregnancy may play a role, along with hormonal changes and other factors.
For some, Hep E may be severe
In countries where it is endemic, Hep E is most common in children. Like Hep A, it often goes undetected because there may be no obvious signs that the child is infected.
Young adults aged 15–40 are most likely to have the usual symptoms, which include jaundice, loss of appetite, a tender liver, abdominal pain and tenderness, nausea, vomiting, fatigue and fever, which can last for up to 2 weeks.
In most people, hepatitis E disappears without treatment and with no long-term effects. However, people with weakened immune systems, such as those with leukaemia and post-organ transplant patients, may develop a chronic form of the disease which can quickly lead to cirrhosis and permanent liver damage.
While there are highly effective vaccines for hepatitis A and hepatitis B, no vaccine is currently available for hepatitis E in Australia, although one was recently approved for use in China.
Protecting your most precious cargo
The new findings on the likely actual burden of Hep E around the world shouldn’t stop pregnant women travelling overseas where and when it’s safe for them to do so.
Most airlines permit mothers-to-be to travel up until week 36. Like Hep E, malaria also poses a risk of severe illness for pregnant women and they shouldn’t travel to destinations where or when the mosquito-borne disease may be a significant risk.
However, the study does highlight just how important it is for pregnant female travellers to:
– Not drink untreated water. If sealed, reputable bottled water isn’t available, treating tap water by boiling or chlorinating will kill both hepatitis viruses.
– Choose safe food and beverages options. (While Hep E is usually transmitted in via drinking water, food-borne transmission may occur from raw shellfish, and uncooked or undercooked meat from infected animals – particularly deer and pigs.)
– Observe strict personal hygiene. Hand washing after using the toilet and before eating.
Avoiding hepatitis in all its forms is important for every traveller – none more so than those carrying precious cargo.
* Dr Bajrovic is the Medical Director of Travelvax Australia.
Read more about travelling during pregnancy.
For more advice on vaccines and medications for your destination, call Travelvax Australia’s free travel health advisory service on 1300 360 164. You can also make an appointment for a one-stop pre-travel medical consultation with a team of medical professionals experienced in travel medicine at your nearest clinic.