WASHINGTON, United States (AFP) — An experimental drug treatment can help monkeys survive an otherwise deadly infection with a tropical virus called Marburg, which is similar to Ebola, researchers said yesterday.

The findings in the journal Science Translational Medicine show the potential for a similar drug treatment against Ebola, the deadly haemorrhagic virus that is sweeping across West Africa in the largest outbreak to date.

There is no available drug or vaccine for Ebola, which has killed 1,350 people and infected 2,473 since March in Sierra Leone, Nigeria, Guinea and Liberia.

Marburg is from the same family as the Ebola virus and also causes severe bleeding, fever, vomiting and diarrhoea.

Fatality rates range from 25 per cent to 80 per cent, and like Ebola, it is transmitted via contact with bodily fluids.

The study tested a Marburg virus drug, made by Canada’s Tekmira Pharmaceuticals, on 16 monkeys.

One group was given the treatment 30-45 minutes after exposure to a lethal dose of the Angola strain of Marburg virus. Other groups were treated one, two and three days following the infection.

“All treated animals in all four studies survived,” said lead author Thomas Geisbert, professor of microbiology and immunology at the University of Texas Medical Branch at Galveston.

The control group included monkeys that were sickened with Marburg virus but were not given the treatment. They all died, beginning one week after they were infected.

The discovery that the treatment worked even three days into the monkeys’ infections shows “real world utility of this technology,” Geisbert told reporters.

Researchers are hopeful that such a treatment could be useful because symptoms of Marburg virus begin showing themselves around that time.

Ebola, too, usually becomes symptomatic within two to 10 days of infection, though the incubation period can last as long as 21 days.

The researchers published a study in The Lancet in 2010 that showed the same technology could be used to create a treatment that would completely protect rhesus monkeys against Ebola.

“This technology may have potential for combating Ebola,” Geisbert said.

The drug works by interfering with how Ebola grows once it penetrates the cells of the body.

In Monrovia, Liberia, violence erupted in an Ebola quarantine zone in Liberia’s capital yesterday as authorities struggled to contain the epidemic, with new suspected cases in Asia sparking fears of it spreading beyond Africa.

Four residents were injured in Monrovia’s West Point slum when soldiers opened fire and used tear gas on crowds as they tried to evacuate a state official and her family from the quarantined quarter.

The crackdown in Liberia comes as authorities around the world are scrambling to stem the worst-ever outbreak of Ebola, with the latest official toll jumping 106 in two days to 1,350 dead.

Liberia, with 576 deaths from 972 diagnosed cases, is the worst hit of the four affected west African countries, with the numbers of deaths and infections rising dramatically.

Ninety-five people died there in a surge of deaths over the weekend, the World Health Organisation said, while only nine died in Sierra Leone and two in Guinea, where the outbreak began.

Liberian President Ellen Johnson Sirleaf quarantined West Point and Dolo Town, to the east of the capital, and imposed a night-time curfew as part of new drastic measures to fight the disease.

From its initial outbreak in Guinea the virus spread to Liberia, Sierra Leone and Nigeria, overwhelming inadequate public health services already battling common deadly diseases such as malaria.

Straining the situation even further, several top officials leading the fight have lost their lives to the disease.

“We have been unable to control the spread due to continued denials, cultural burying practices, disregard for the advice of health workers and disrespect for the warnings by the government,” Sirleaf said.