CDC update on Ebola
The Centers for Disease Control and Prevention have taken the unusual step of revamping their main website in response to the significant outbreak of Ebola Hemorrhagic Fever in central Africa. Traditionally, outbreaks of this disease have had epidemiologists worried when they occur, but fortunately the severity of the disease also means that it outbreaks have been contained rapidly, and the number of deaths historically have not been high with at most a few hundred deaths. The mortality in all outbreaks however has been high, with up to a 90% fatality rate in a 2003 outbreak in the Dem. Republic of the Congo. Currently, no treatment or preventative vaccine exists for Ebola virus.
The current outbreak is historic in its severity; as of late September, an outbreak in West Africa has affected over 6000 people with about a 50% death rate. The origin of this and previous outbreaks is similar, with the virus moving from its native reservoir in bats to non-human primates, and then to humans. Outbreaks in human populations then occur when human to human transmission occurs with high frequency. The CDC estimates that this number of cases will continue to rise, with potentially 21,000 cases by the end of September, and estimates from the World Health Organization are similar in scope.
To curtail this rise in cases, immediate measures need to be instituted, primarily consisting of ensuring that sick individuals are cared for in equipped Ebola Treatment Units, or if full, in home/community settings with appropriate infection control procedures in place including safe burial procedures. The CDC currently has over 700 staff members actively working on the epidemic at labs in the US, and have deployed almost 100 specialists to offer assistance in the affected region. Part of their work oversees is to assist with screening measures to prevent the epidemic from spreading to other regions, and ensuring that medical and humanitarian resources can reach the affected areas. For US citizens, a non-essential travel alert for this region has been issued.
Public health investigators think that the current outbreak is so severe for a variety of reasons. Seasonal climate variation has potentially created an environment where the virus flourishes in its animal reservoir, or perhaps facilitates transfer from the bat to other transient animal carriers. Development into the jungle has eased the movement of people into regions where the virus is natively found, making animal-human transmission easier. Additionally, political turmoil makes it more difficult for health officials to rapidly respond when an outbreak occurs, and the current outbreak region spreads over several political jurisdictions. Together, these factors have combined for a perfect storm enabling a much greater outbreak than previously seen. The good news in all of this is that there is an international response to the outbreak, and the likelihood of the epidemic spreading to the United States remains very small, even when patients are brought to the US for treatment.