Ebola activity heats up as West Africa's rainy season begins

In its weekly epidemiologic profile of the outbreak today, the World Health Organization (WHO) said Ebola activity in Guinea and Sierra Leone has become more intense and widespread since May 10, when the region saw cases hit a 10-month low.

Last week the two countries reported 25 new lab-confirmed cases, 13 in Guinea and 12 in Sierra Leone. The number is up from 12 reported the week before.

Overall, the total of confirmed, probable, and suspected cases in the two countries and Liberia—which is now Ebola free—has risen to 27,145, including 11,147 deaths, the WHO said.

No health worker infections were reported, keeping the total at 869, 507 of them fatal.

Concerns over unknown transmission chains

The WHO said several of the new cases are from unknown sources in areas that haven't reported any confirmed cases in several weeks. It said rigorous contact tracing, active case finding, and infection prevention and control are needed to break transmission chains and get cases down to zero, but the onset of rainy season will make field operations more difficult in the weeks and months ahead.

Guinea's 13 cases were reported in four districts, with 7 in Forecariah district, an area that borders Sierra Leone. Other cases were in Boke (1), Dubraka (4), and Fria (1) districts. Boke borders Guinea-Bissau, and the western district of Dubreka borders Conakry, the country's capital.

The cases in Boke and Dubreka are from known contacts, but the case in Fria district came from an unknown transmission source, and responders investigating the illness met active and passive resistance in both Fria and Telimele districts. Earlier this week, a United Nations official in Guinea warned that continued violence and resistance is a threat to battling the disease and called for calm.

Threat to childbearing survivors

Sierra Leone's 12 cases were reported from 3 districts, with 8 of them in the densely populated Kaffu Bullom chiefdom in Port Loko district. The WHO said most of those cases are linked to a single case that was imported from Kambia district, an area just north of Port Loko on the border with Guinea.

Meanwhile, the country's Kambia district reported its first case in 2 weeks, and so far investigators haven't been able to find a link to a previous case, and they suspect that an active transmission chain has been smoldering undetected in the area for several weeks. The WHO said responders have reported several recent community resistance incidents in Kambia district.

Three of Sierra Leone's cases were in Freetown, and so far initial investigations haven't linked any of them to any known transmission chains. One involved a stillborn child who tested positive for the disease. The mother's test was negative, though serologic tests suggested she had been exposed to the virus.

The WHO said the case underscores the need for pregnancy and births to be closely monitored in women who survive their Ebola infections.

Repurposed drugs for Ebola

Researchers who used molecular screening to test about 2,600 drugs approved for other indications for possible use against the Zaire Ebola virus strain found that 80 had some action against the virus. Zaire is the subtype circulating in West Africa's outbreak countries.

The team, led mainly by researchers from the US Army Medical Research Institute of Infectious Diseases (USAMRIID) and Horizon Discovery, Inc., based in Cambridge, Mass., published its findings today in Science Translational Medicine.

They used an in vitro infection assay for their first screening, and the drugs that showed some activity had several different mechanisms of action and ranged from estrogen receptor modulators to antidepressants.

Their screening with an in vivo murine Ebola virus infection model confirmed that several drugs might help protect against the virus, including bepridil and sertraline. The researchers concluded that, because the drugs are already approved, they could quickly advance to clinical trials and might be useful for battling Ebola.

See also:

June 3 WHO Ebola situation update

Jun 3 Sci Transl Med abstract

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