News & Information About Ebola

Tag: zaire

1995 Outbreak Summary

315 cases with 254 deaths occurred in 1995 when Ebola broke out in the Kitwit area of the Democratic Republic of Congo which was known as Zaire at the time.  The outbreak was one of the largest since the first documented outbreak in 1976 when Zaire witnessed 318 cases of the virus.

The source of infection was traced to a single index patient who fell ill on the 6th of January 1995 and died in a local hospital on the 13th of the same month. This resulted in direct infections of his family members and a secondary wave of at least 10 infections in his extended family. It is assumed that the index patient contracted the infection from a natural reservoir since no prior contact with an Ebola carrier was found.

Several deaths occurred in the initial village and nearby villages where the cause of death was noted as dysentery. It is thought that several of these cases were in fact the result of the virus but were not recognized as such until much later in May when it was confirmed. It is very likely that at least a portion of these cases formed part of the initial transmission chain for the outbreak.

May 1995 saw the involvement of international partners and health organizations in an effort to contain the outbreak. The last case was documented in June 1995 however at least one asymptomatic case appears to have occurred after the last reported case. Officials attributed the successful containment to patient isolation, contact tracing and education. The outbreak occurred 21 years after the first documented outbreak raising significant awareness about the disease and the potential for the virus to have a widespread impact beyond the original scope of understanding. The similarity in case counts and mortality rates between the two outbreaks confirmed that the virus remained a serious threat.

List of Historical Outbreaks

Ebola was first isolated in 1976 during the first recorded outbreak in the Democratic Republic of Congo known as Zaire at the time. The West African outbreak of 2014 is the largest since it was isolated. The virus was named Ebola after a river near the village where the first documented case occurred.

The below table shows previous outbreaks of Ebola including the strain and the mortality rate per outbreak. The mortality rate of the Reston strain is far lower than other strains. It is widely believed that the Reston strain could be utilised and patents to this affect are already in the public domain.

Year Country Strain Cases Deaths CFR
1976 Zaire EBOV 318 280 88.00%
1976 Sudan SUDV 284 151 53.00%
1976 England SUDV 1 0 0.00%
1977 Zaire EBOV 1 1 100.00%
1979 Sudan SUDV 34 22 65.00%
1989–1990 Philippines RESTV 3 0 0.00%
1990 United States RESTV 4 0 0.00%
1994 Gabon EBOV 52 31 60.00%
1994 Côte d’Ivoire TAFV 1 0 0.00%
1995 Zaire EBOV 315 254 81.00%
1996 Gabon EBOV 37 21 57.00%
1996 South Africa EBOV 2 1 50.00%
1996–1997 Gabon EBOV 60 45 75.00%
2000–2001 Uganda SUDV 425 224 53.00%
2001–2002 Gabon EBOV 122 96 79.00%
2002–2003 Republic of the Congo EBOV 143 128 90.00%
2003 Republic of the Congo EBOV 35 29 83.00%
2004 Sudan SUDV 17 7 41.00%
2004 Russia EBOV 1 1 100.00%
2007 Democratic Republic of the Congo EBOV 264 187 71.00%
2007–2008 Uganda BDBV 149 37 25.00%
2008 Philippines RESTV 6 0 0.00%
2008–2009 Democratic Republic of the Congo EBOV 32 14 45.00%
2012 Uganda SUDV 24 17 71.00%
2012 Democratic Republic of the Congo BDBV 77 36 47.00%

Limited studies have concluded that the virus may be considerably older. A study observing RNA mutations placed the potential early strains of the virus at around 800 years old. Ebola outbreaks have traditionally been limited to small villages and residents have been observed implementing isolation of the sick without the intervention of Western medicine.

The plague of Athens ending 430 B.C. has been compared to an ancient Ebola virus. Historical accounts of the plague cite symptoms similar to Ebola most notably an “empty cough” which is not consistent with other possible diseases including small pox and measles. There is insufficient evidence to fully understand the exact cause of the plague.

Ebola may have existed for thousands of years without human knowledge. Prior to the 2014 outbreak, the virus was considered likely to burn out quickly due to low incubation periods and sudden deterioration of an infected individual to death.  The 2014 strain appears to have a slightly longer incubation period which has given rise to the suspicion it has mutated.

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