Ebola – a term that sends shivers in everyone’s mind

Uganda is suffering from another Ebola outbreak.  Its fourth since 2000. 

For those that are not familiar with PROMED, you can find postings and listing on the outbreak at ProMED Ebola recent posting .   ProMED is an open source system that permits timely reporting on any disease activity from local to national jurisdictions.  A useful and essential tool in monitoring global disease spread.  About ProMED.  

Ebola was first recognized in Sudan in 1976.  It has surfaced in a number of central African countries stretching from Uganda to the Ivory Coast.  Four distinct subtypes of the virus  have been located.  No natural host has yet been identified, although suspicion remains with fruit bats.  Initial human illness tending to occur through infected monkey meat consumption.  Several occupationally related cases have been related to necropsy of monkeys and to care of infected persons.

The prototypical view of North American or European workers entering an African village wearing space suit type biocontainment units fuels the international fear associated with the illness. 

The dramatic characteristic of the illness being the high mortality rate, predominately due to hemorrhagic fever compounded by limited medical intervention.  Mortality rates of greater than 50% are typical.  The most recent Ugandan outbreaks are suggestive of a less virulent strain with only 20-25% mortality.  While person to person occurs, sustained transmission has not been the norm when good hygienic precautions are put into place.

In total some 2270 persons have been infected, 1625 deaths with a combined mortality of just over 70%.  Ebola has surfaced on about two dozen occasions over the last 35 years, seven of those outbreaks effected more than 100 persons, nine others between 10 and 100. 

The current outbreak has infected 20 patients as of the ProMED posting, with 14 deaths.   Based on the reports, WHO, CDC, and Ugandan Ministry of Health are actively involved in containing the situation.  A simplified science blog posting linked with National Geographic provides a good overview National geographic science blog on Ebola

Ebola may not been the most critical current zoonotic threat, but it does stimulate a fear reaction that is a reminder of the hidden threats that lie waiting in animal species.  As a comparsion, H5N1 (avian influenza) has infected 607 persons total with a 58% fatality rate, SARS (possibly also bats) affected about 8000 people with a 9% fatality rate; rabies (several species including bats) may top zoonotic list with an estimated 55,000 deaths annually and a case fatality of greater than 97%.