Donated blood from a man who ate pork in France has infected a six-year-old boy with a form of hepatitis that is rare in Australia.
It is the first confirmed case of the hepatitis E virus being transferred through blood donated in Australia.
Hepatitis E, also known as HEV, has been known to cause cirrhosis, or permanent liver damage in liver transplant patients.
Most people recover within six weeks, and many won't have any symptoms, but HEV can be severe for pregnant women and people with pre-existing liver conditions or compromised immune systems.
The boy contracted the virus from donated plasma used during a liver transplant operation in 2014 but it was not detected until early 2015 – about six months later.
The Australian Red Cross Blood Service tested archived samples of all 18 blood donations the boy received and discovered one of them was positive.
It emerged that before giving blood, the donor – who had no symptoms – had eaten pork in the south of France, which is known to have prevalence of HEV.
The boy was treated with an antiviral medication called Ribavirin for three months. After this time his liver enzyme levels returned to normal and the virus could no longer be detected.
The case has been documented in a Medical Journal of Australia report co-written by staff from the Australian Red Cross Blood Service, PathWest Laboratory, Princess Margaret Hospital for Children in Perth, and the Victorian Infectious Diseases Reference Laboratory in Melbourne.
"...While the risk in Australia is low compared with other countries, we report the first confirmed Australian case of transmission by transfusion," wrote the authors, lead by the blood service's Veronica Hoad.
"Chronic infection can occur in immunocompromised individuals and may lead to cirrhosis; however, early recognition and treatment generally results in viral clearance.
"Clinicians should remain alert to the possibility of HEV infection."
The blood service has launched a large national HEV prevalence study in blood donors to determine whether they need to change their risk management protocols. A preliminary study has revealed HEV was present at a rate of about 1 in 14,799 Australian donations, the authors reported.
It is typically found in developing countries, in the faeces of infected people and animals and is spread by eating or drinking contaminated food or water. It can be contracted by eating undercooked meat, particularly pork liver, venison and wild boar.
The first known outbreak of Hep E in Australia was in 2013 and 2014 when 17 people fell ill after eating pork liver pate at the same NSW restaurant.
There were 41 notified cases nationally in both 2015 and 2016, government surveillance data shows, and 14 cases so far in 2017. Most reported cases involved an Australian contracting HEV overseas.
However, the authors of the report wrote the true infection burdon in Australian "remains unknown," as many infected don't have symptoms.
A spokesman for the Blood Service said Australia's blood supply continued to be one of the safest in the world. He said there had been no other blood donor transmissions of HEV since this first reported case.
"This is due to the low prevalence of hepatitis E in the Australian population combined with our strict donor eligibility guidelines," the spokesman said.
"In the wake of this incident, the Blood Service reviewed all available evidence and concluded that the ongoing risk to the blood supply remains very low, and does not warrant the introduction of any further testing of donated blood."