Random Analytics: Ebola 2014 (to 9 Jun 2014)

by Shane Granger

The latest outbreak of Ebola which had been on the decline in early May has now returned with a vengeance. According to the latest update from the World Health Organisation (Regional Office for Africa) there have been 437-clinical cases and 232 fatalities. Guinea has borne the brunt of the disease with 344-clinical cases (215-deaths), the second impacted country Liberia has had 12-clinical cases (11-deaths) and newly impacted country of Sierra Leone has had 81-cases (6-deaths). These numbers are still likely to change.

According to my notes, this outbreak is now the worst on record in terms of case numbers, extending beyond the 425-cases (224-deaths) experienced during the Ebola Sudan outbreak in Uganda back in 2000-2001. Another two grim milestones is that this is the first Ebola outbreak to cross a land border and the first outbreak to impact on three separate countries.

Here are four charts/infographics looking at the most recent outbreak.

Ebola Virus Disease Outbreak (Guinea Prefectures 2014)

01 - Ebola_GuineaOutbreak_140609

***** Please note that this infographic of the EVD was updated with public source information to 1200hrs 9 June 2014 (EST) *****

From the World Health Organisation Regional Office for Africa. Ebola virus disease, West Africa (Situation as of 5 June 2014). Excerpt:

Guinea

Between 2 and 3 June 2014, 11 new cases (8 confirmed, 1 probable and 2 suspected) and 3 new deaths were reported from Conakry (7 new cases and 1 death), Guéckédou (2 new cases and 1 death), Telimele (1 new case and 0 death) and Boffa (1 new case and 1 death). This brings the cumulative total number of cases and deaths attributable to EVD in Guinea to 344 (laboratory confirmed 207, probable 81 and suspected 56) including 215 deaths.

The geographical distribution of these cases and deaths is as follows: Conakry (65 cases and 27 deaths; Gueckedou, 193 cases and 143 deaths; Macenta, 44 cases and 26 deaths; Dabola, 4 cases and 4 deaths; Kissidougou, 7 cases and 5 deaths; Dinguiraye, 1 case and 1 death; Telimele, 23 cases and 5 deaths; and Boffa, 7 cases and 4 deaths. In terms of isolation, 31 patients are currently hospitalized (6 in Conakry, 9 in Guéckédou, 15 in Telimele and 1 in Boffa).

Sierra Leone

Between 2 and 5 June 2014, 9 new suspected cases were reported bringing the total number of EVD clinical cases to 81 (31 confirmed, 3 probable, and 47 suspected) including 6 deaths. Kailahun district is the epicentre of the outbreak in Sierra Leone. Eleven (11) cases are currently in isolation at Kenema Hospital. The number of contacts currently being followed-up is 30. Community resistance is hindering the identification and follow-up of contacts.

Notes: The map graphic was taken from Wikipedia (then amended).

Ebola across Africa

02 - Ebola_AcrossAfrica_140609

***** Please note that this infographic of the EVD was updated with public source information to 1200hrs 9 June 2014 (EST). EBOV = Ebola Zaire, SUDV = Ebola Sudan, BDBV = Ebola Bundibugyo and TAFV = Ebola Ivory Coast *****

The Ebola across Africa infographic details the country specific outbreaks of the EVD since it was first discovered in 1976 (with a 1972 retrospective case from Zaire included). As the map shows the bulk of the outbreaks have occurred within central Africa and the most deadly, Ebola Zaire causing the most cases in the Democratic Republic of Congo (formally Zaire). The most recent outbreak has actually occurred in West Africa, originating from Guinea and is a new isolate of Ebola Zaire (Gueckedou and Kissidougou).

As an additional point of interest I have also added the Health Expenditure per capita for each country in 2012 $USD (source: World Bank).

Notes: The 1976 – 2004 outbreaks of Ebola Sudan occurred in the bottom half of Sudan (now South Sudan). Zaire was renamed the Democratic Republic of Congo in 1997.

Ebola (Top 10 Outbreaks by Case Numbers)

03 - Ebola_Top10OutbreaksByCaseNo_140609

***** Please note that this infographic of the EVD was updated with public source information to 1200hrs 9 June 2014 (EST) *****

The next chart displays the top 10 outbreaks in order of case numbers and each horizontal bar is filled with the flag of the country where the outbreak occurred. With clinical cases reaching 344 in Guinea, 81 in Sierra Leone and 12 in Liberia the EBOV17 coded outbreak has now become largest (437) based on case numbers. The second largest outbreak (SUDV4) was of Ebola Sudan in Uganda (2000) when 425 became infected and 224 died. The recent outbreak is the first to migrate across international land borders. The only other recording of an EVD that jumped borders prior to this outbreak was the 10th worst outbreak (EBOV8) when a doctor caught the disease in Gabon and subsequently took an international flight to South Africa where he became ill and infected other health workers.

Notes: EBV outbreaks in order from lowest to highest. 10th: EBOV8 (Gabon/South Africa), 9th: EBOV9 (Gabon), 8th: EBOV11 (Republic of Congo), 7th: BDBV01 (Uganda), , 6th: EBOV15 (Democratic Republic of Congo), 5th: SUDV1 (technically Sudan but would now be South Sudan), 4th: EBOV6 (Zaire but now the DRC), 3rd: EBOV2 (Zaire but now the DRC), 2nd: SUDV4 (Uganda) and the current, now deadliest outbreak EBOV17 (Guinea/Liberia/Sierra Leone).

Ebola (Cases by Classification and Year)

04 - Ebola_CasesbyClassYear_140609

***** Please note that this infographic of the EVD was updated with public source information to 1200hrs 9 June 2014 (EST) *****

The final chart shows cases by classification (Ebola Zaire, Sudan, Bundibugyo, Reston and Ivory Coast) by year and then split into those recovered or those deceased (following in a red variant). As you can see the initial outbreak in 1976 of the both Ebola Zaire and Ebola Sudan was the most significant year with 603 cases and 431 deaths (a combined Case Fatality Rate of 71.5%). With up to 437 clinical cases so far the 2014 Ebola Zaire outbreak is now the second worst in terms of case numbers.

Notes: Several years had just one case. They are 1972 (a retrospective fatality of Ebola Zaire in Zaire), 1977 (a single case of Ebola Zaire in Zaire), 1988 (an accidental infection of Ebola Zaire in Porton Down, UK) and 2011 (a single fatality of Ebola Sudan in Uganda). The 2014 numbers are currently provisional.

Key Facts: (source: Fact Sheet 103, WHO, last updated March 2014)

  • The Ebola virus causes Ebola virus disease (EVD; formerly known as Ebola haemorrhagic fever) in humans;
  • EVD outbreaks have a case fatality rate of up to 90%;
  • EVD outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests;
  • The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission;
  • Fruit bats of the Pteropodidae family are considered to be the natural host of the Ebola virus;
  • No specific treatment or vaccine is available for use in people or animals.

Acknowledgements: Data for this infographic was sourced from official reports from the World Health Organisation. I have also utilised resources from the CDC, CIDRAP, H5N1, Virology Down Under and National Geographic.

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