HONG KONG (Reuters) - Ignorance is fuelling the spread of hepatitis B in Asia, where patients are failing to get proper treatment and not enough is done to reduce transmission of the virus from mother to child, an expert said.

The 10th leading cause of death worldwide, chronic hepatitis B affects 360 million people globally.

Of these, 281 million are in Asia, and one out of every four of them will die from either cirrhosis — scarring of the liver — or liver cancer later in life.

Symptoms such as jaundice, fatigue, abdominal pain, loss of appetite, nausea and joint pain may not surface in 30 percent of cases, and they are even less common in children.

As such, many people usually don't know they are infected until it is too late, and those who do have little impetus to get treated or have regular check-ups, according to the results of a survey carried out in 10 places in Asia this year.

"Ignorance helps the transmission of the disease and the survey finds this ignorance results in people giving up on the chance of proper treatment ... they don't think it's important to be treated because they don't have symptoms," said Nancy Leung, an expert on the disease and associate professor at the Chinese University's department of medicine and therapeutics.

The survey covered 1,500 people diagnosed with chronic hepatitis B in China, Hong Kong, South Korea, Malaysia, the Philippines, Indonesia, Singapore, Taiwan, Thailand and Vietnam and who were taking anti-viral drugs to suppress the virus.

Although 77 percent of them said they knew "an average or a great deal" about the disease, substantial numbers of them (36 and 27 percent, respectively) were unaware that the main routes of transmission were from mother-to-child and through sex.

Overwhelming numbers mistook hepatitis B for hepatitis A, with 73 percent in China, 70 percent in the Philippines and 63 percent in Singapore thinking that "eating infected food" was the major cause.

Thirty-eight percent did not know how they came to be infected. In China and the Philippines, 53 percent and 46 percent thought they caught the virus from food.

In Indonesia and Vietnam, 57 percent and 44 percent cited "poor health" as the cause.

Highlighting the seriousness of the disease, Leung said 10 percent of Hong Kong's seven million strong population, or 700,000 people, suffer from chronic hepatitis B. And despite the city's advanced health care system, only a fraction of patients are getting adequate care.

"In Hong Kong, less than 10 percent of patients with chronic hepatitis B are being treated, only 20 percent are being properly monitored and assessed," Leung said.

Almost all chronic hepatitis B sufferers were infected before they were born or when they were very young.

In Hong Kong, 60 percent of sufferers are believed to have been infected by their mothers, while 40 percent were infected when they were very young, usually through blood contact with infected playmates via open sores and small breaks in the skin.

"Infections in adulthood would in all likelihood not be chronic, they would be cured," said Leung, referring to the intense immune response such an infection would trigger in an adult, who would be able to get rid of the virus completely.

Conversely, in an infant or a very young child, they are very often unable to flush out the virus, and it remains in their livers, multiplying and then creating havoc over time.