'1 in 5 chance' Ebola will spread to the US by the end of September

Date: Sep-10-2014Writing in the journal PLOS Currents: Outbreaks, a team of experts claim it is likely that Ebola will make its way to the US, estimating there is a 20% chance this could occur by the end of this month. However, US health care is expected to halt transmission, limiting outbreaks to isolated cases.

The researchers suggest Ebola could spread beyond Africa via the international travel hubs in Nigeria.

The World Health Organization (WHO) report that 1,841 people in West African nations have died from Ebola during the current outbreak, with a total of 3,685 confirmed or suspected cases. A recent report in the journal Science (not connected to the PLOS report) estimated that the epidemic will reach 10,000 cases by the end of September.

The virus is transmitted via contact with the bodily fluids of an infected person, and it can take up to 21 days after infection for symptoms to appear. These symptoms include fever, muscle weakness and sore throat, and later vomiting, rash and bleeding.

There is no clinically available vaccine for Ebola. However, earlier this week, Medical News Today reported on the development of a vaccine capable of generating long-term immunity against Ebola in monkeys, which is now entering phase 1 clinical trials in humans.

Analysis compares international travel patterns with rate of transmission

In the new analysis, researchers compared international travel patterns with estimates on the rate of transmission to calculate the speed at which Ebola might spread to different regions of the globe.

The report says that the disease is initially expected to spread to currently unaffected African countries.

Although there is not a high level of international travel between some of the affected countries - such as Liberia and Sierra Leone - the researchers suggest Ebola could spread beyond Africa via Nigeria. This is because Nigeria, where the outbreak has also spread, has many international travel links. An estimated 6,000 passengers fly from Nigeria to the US every week.

"We would assume that the US would have sufficient capacity to test people and treat them," says co-author Ira Longini, PhD, a professor of biostatistics in the University of Florida colleges of Medicine and Public Health and Health Professions. "We would not expect any real transmission in the US."

The researchers say that as the outbreak affects more metropolitan areas with international airports - such as Dakar, the capital of Senegal, where Ebola has spread to in the past week - it becomes more likely that people who do not know they are infected with the virus will spread Ebola to other countries and continents.

The assumption that preventing international air travel would halt the outbreak is also challenged in the report, which demonstrates that in reality, such measures would have little effect. Reducing air travel by as much as 80% would only temporarily prevent the spread of Ebola, the report claims.

Ira Longini explains:

"Studies have shown the quarantining of entire villages and countries is highly ineffective, and this analysis shows that yet again. Surveillance and containment, which includes the isolation of cases and quarantine of close contacts, is the only intervention strategy that works that is available."

The current risk of the virus spreading to additional countries is described by Longini and colleagues as "moderate," but these risks will grow as the virus continues to defy containment.

In other Ebola-related news, WHO recently reported that the Ebola outbreak in the Democratic Republic of Congo is "distinct and independent" from the strains circulating in West Africa.

Written by David McNamee

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Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.