1. Morens DM, Folkers GK, Fauci AS (2004) The challenge of emerging and re-emerging infectious diseases. Nature430: 242–249. [PubMed]
2. Holmes EC (2013) What can we predict about viral evolution and emergence?Curr Opin Virol3: 180–184. doi: 10.1016/j.coviro.2012.12.003[PMC free article][PubMed]
3. Zinsstag J, Schelling E, Waltner-Toews D, Tanner M (2011) From "one medicine" to "one health" and systemic approaches to health and well-being. Prev Vet Med101: 148–156. doi: 10.1016/j.prevetmed.2010.07.003[PMC free article][PubMed]
4. Parkes MW, Bienen L, Breilh J, Hsu L-N, McDonald M, et al. (2005) All Hands on Deck: Transdisciplinary Approaches to Emerging Infectious Disease. EcoHealth2: 258–272.
5. Lefebvre A, Fiet C, Belpois-Duchamp C, Tiv M, Astruc K, et al. (2014) Case fatality rates of Ebola virus diseases: a meta-analysis of World Health Organization data. Med Mal Infect44: 412–416. doi: 10.1016/j.medmal.2014.08.005[PubMed]
6. Gonzalez JP, Nakoune E, Slenczka W, Vidal P, Morvan JM (2000) Ebola and Marburg virus antibody prevalence in selected populations of the Central African Republic. Microbes Infect2: 39–44. [PubMed]
7. Leroy EM, Baize S, Volchkov VE, Fisher-Hoch SP, Georges-Courbot MC, et al. (2000) Human asymptomatic Ebola infection and strong inflammatory response. Lancet355: 2210–2215. [PubMed]
8. Goeijenbier M, van Kampen JJ, Reusken CB, Koopmans MP, van Gorp EC (2014) Ebola virus disease: a review on epidemiology, symptoms, treatment and pathogenesis. Neth J Med72: 442–448. [PubMed]
9. Becquart P, Wauquier N, Mahlakoiv T, Nkoghe D, Padilla C, et al. (2010) High prevalence of both humoral and cellular immunity to Zaire ebolavirus among rural populations in Gabon. PLoS One5: e9126 doi: 10.1371/journal.pone.0009126[PMC free article][PubMed]
10. Bellan SE, Pulliam JR, Dushoff J, Meyers LA (2014) Ebola control: effect of asymptomatic infection and acquired immunity. Lancet384: 1499–1500. doi: 10.1016/S0140-6736(14)61839-0[PMC free article][PubMed]
11. Leroy EM, Kumulungui B, Pourrut X, Rouquet P, Hassanin A, et al. (2005) Fruit bats as reservoirs of Ebola virus. Nature438: 575–576. [PubMed]
12. Leroy EM, Epelboin A, Mondonge V, Pourrut X, Gonzalez JP, et al. (2009) Human Ebola outbreak resulting from direct exposure to fruit bats in Luebo, Democratic Republic of Congo, 2007. Vector Borne Zoonotic Dis9: 723–728. doi: 10.1089/vbz.2008.0167[PubMed]
13. Leroy EM, Rouquet P, Formenty P, Souquiere S, Kilbourne A, et al. (2004) Multiple Ebola virus transmission events and rapid decline of central African wildlife. Science303: 387–390. [PubMed]
14. Rouquet P, Froment JM, Bermejo M, Kilbourn A, Karesh W, et al. (2005) Wild animal mortality monitoring and human Ebola outbreaks, Gabon and Republic of Congo, 2001–2003. Emerg Infect Dis11: 283–290. [PMC free article][PubMed]
15. Bermejo M, Rodriguez-Teijeiro JD, Illera G, Barroso A, Vila C, et al. (2006) Ebola outbreak killed 5000 gorillas. Science314: 1564 [PubMed]
16. Lahm SA, Kombila M, Swanepoel R, Barnes RF (2007) Morbidity and mortality of wild animals in relation to outbreaks of Ebola haemorrhagic fever in Gabon, 1994–2003. Trans R Soc Trop Med Hyg101: 64–78. [PubMed]
17. Pourrut X, Kumulungui B, Wittmann T, Moussavou G, Delicat A, et al. (2005) The natural history of Ebola virus in Africa. Microbes Infect7: 1005–1014. [PubMed]
18. Wittmann TJ, Biek R, Hassanin A, Rouquet P, Reed P, et al. (2007) Isolates of Zaire ebolavirus from wild apes reveal genetic lineage and recombinants. Proc Natl Acad Sci USA104: 17123–17127. [PMC free article][PubMed]
19. Graham RL, Baric RS (2010) Recombination, reservoirs, and the modular spike: mechanisms of coronavirus cross-species transmission. J Virol84: 3134–3146. doi: 10.1128/JVI.01394-09[PMC free article][PubMed]
20. Worobey M, Han GZ, Rambaut A (2014) A synchronized global sweep of the internal genes of modern avian influenza virus. Nature508: 254–257. doi: 10.1038/nature13016[PMC free article][PubMed]
21. Shaman J, Goldstein E, Lipsitch M (2011) Absolute humidity and pandemic versus epidemic influenza. Am J Epidemiol173: 127–135. doi: 10.1093/aje/kwq347[PMC free article][PubMed]
22. Roche B, Drake JM, Brown J, Stallknecht DE, Bedford T, et al. (2014) Adaptive evolution and environmental durability jointly structure phylodynamic patterns in avian influenza viruses. PLoS Biol12: e1001931 doi: 10.1371/journal.pbio.1001931[PMC free article][PubMed]
23. Imai M, Watanabe T, Hatta M, Das SC, Ozawa M, et al. (2012) Experimental adaptation of an influenza H5 HA confers respiratory droplet transmission to a reassortant H5 HA/H1N1 virus in ferrets. Nature486: 420–428. doi: 10.1038/nature10831[PMC free article][PubMed]
24. Smith GJ, Vijaykrishna D, Bahl J, Lycett SJ, Worobey M, et al. (2009) Origins and evolutionary genomics of the 2009 swine-origin H1N1 influenza A epidemic. Nature459: 1122–1125. doi: 10.1038/nature08182[PubMed]
25. Lau SK, Woo PC, Li KS, Huang Y, Tsoi HW, et al. (2005) Severe acute respiratory syndrome coronavirus-like virus in Chinese horseshoe bats. Proc Natl Acad Sci USA102: 14040–14045. [PMC free article][PubMed]
26. Li W, Shi Z, Yu M, Ren W, Smith C, et al. (2005) Bats are natural reservoirs of SARS-like coronaviruses. Science310: 676–679. [PubMed]
27. Lloyd-Smith JO, Schreiber SJ, Kopp PE, Getz WM (2005) Superspreading and the effect of individual variation on disease emergence. Nature438: 355–359.5. [PubMed]
28. Qu XX, Hao P, Song XJ, Jiang SM, Liu YX, et al. (2005) Identification of two critical amino acid residues of the severe acute respiratory syndrome coronavirus spike protein for its variation in zoonotic tropism transition via a double substitution strategy. J Biol Chem280: 29588–29595. [PubMed]
29. Kan B, Wang M, Jing H, Xu H, Jiang X, et al. (2005) Molecular evolution analysis and geographic investigation of severe acute respiratory syndrome coronavirus-like virus in palm civets at an animal market and on farms. J Virol79: 11892–11900. [PMC free article][PubMed]
30. Song HD, Tu CC, Zhang GW, Wang SY, Zheng K, et al. (2005) Cross-host evolution of severe acute respiratory syndrome coronavirus in palm civet and human. Proc Natl Acad Sci U S A102: 2430–2435. [PMC free article][PubMed]
31. Wang LF, Eaton BT (2007) Bats, civets and the emergence of SARS. Curr Top Microbiol Immunol315: 325–344. [PubMed]
32. Plowright RK, Eby P, Hudson PJ, Smith IL, Westcott D, et al. (2015) Ecological dynamics of emerging bat virus spillover. Proc Biol Sci282: 20142124 doi: 10.1098/rspb.2014.2124[PMC free article][PubMed]
33. Yates TL, Mills JN, Parmenter CA, Ksiazek TG, Parmenter RR, et al. (2002) The ecology and evolutionary history of an emergent disease: hantavirus pulmonary syndrome. Bioscience52: 989–998.
34. Mills JN (2005) Regulation of rodent-borne viruses in the natural host: implications for human disease. Arch Virol Suppl: 45–57. [PubMed]
35. Ostfeld RS, Canham CD, Oggenfuss K, Winchcombe RJ, Keesing F (2006) Climate, deer, rodents, and acorns as determinants of variation in lyme-disease risk. PLoS Biol4: e145 [PMC free article][PubMed]
36. LoGiudice K, Ostfeld RS, Schmidt KA, Keesing F (2003) The ecology of infectious disease: effects of host diversity and community composition on Lyme disease risk. Proc Natl Acad Sci USA100: 567–571. [PMC free article][PubMed]
37. Schwanz LE, Voordouw MJ, Brisson D, Ostfeld RS (2011) Borrelia burgdorferi has minimal impact on the Lyme disease reservoir host Peromyscus leucopus. Vector Borne Zoonotic Dis11: 117–124. doi: 10.1089/vbz.2009.0215[PubMed]
38. Hersh MH, LaDeau SL, Previtali MA, Ostfeld RS (2014) When is a parasite not a parasite? Effects of larval tick burdens on white-footed mouse survival. Ecology95:1360–1369. [PubMed]
39. Previtali MA., Ostfeld RS, Keesing F, Jolles AE, Hanselmann R, et al. (2012) Relationship between pace of life and immune responses in wild rodents. Oikos121:1483–1492.
The World Health Organization (WHO) has declared Nigeria to be free of Ebola virus transmission.
In the words of WHO, “This is a spectacular success story that shows that Ebola can be contained. The story of how Nigeria ended what many believed to be potentially the most explosive Ebola outbreak imaginable is worth telling in detail. Such a story can help the many other developing countries that are deeply worried by the prospect of an imported Ebola case and eager to improve their preparedness plans. Many wealthy countries, with outstanding health systems, may have something to learn as well.”
On July 23, 2014, the first Ebola case in Nigeria occurred. Of concern at the time was that it occurred in Lagos – a city of 21 million people. The United States Consul General in Nigeria, Jeffrey Hawkins, said it best at the time, “The last thing anyone in the world wants to hear is the 2 words, ‘Ebola’ and ‘Lagos’ in the same sentenc.,” since it bought up the images of an “apocalyptic urban outbreak”.
Fortunately, that never happened and the case study provides a model to other countries (including the United States) on how to contain and eradicate the virus when it first presents itself.
The first Ebola outbreakAccording to WHO, the Ebola virus entered Lagos on July 20th via an infected Liberian air traveller. Before, during, and after the flight he showed symptoms. He vomited during the flight, on arrival and in the private car that drove him to a private hospital. At the hospital, he told staff that he had malaria and denied any contact with an Ebola patient. Later, it was learned that he had visited his Ebola infected sister while she was in a hospital and he also attended her traditional funeral and burial ceremony.
Five days after arriving in Lagos, the man died. Over the coming days, 9 doctors and nurses became infected and 4 of them died. One peace officer who transported the man also died.
The second Ebola outbreakOn August 1st, 2014 , a close contact of the first Ebola case flew to Port Harcourt (Rivers State region) seeking care with a private physician. Subsequently, the doctor developed symptoms on August 10th and died of Ebola on August 23rd.
An investigation undertaken by a team of epidemiologists from the Nigerian Centre for Disease Control (NCDC), the Nigeria Field Epidemiology and Laboratory Training Programme and the State Ministry of Health, assisted by WHO, revealed an alarming number of high-risk and very high-risk exposures for hundreds of people during this exposure.
Fortunately. Dr Rui Vaz, the head of WHO’s country office in Nigeria, visited the Port Harcourt area to assess the situation there and informed the State’s Governor of the potentially explosive situation and made his advice crystal clear: “All required resources must be immediately mobilized to stop this outbreak.”
42 Days Without EbolaSince those two outbreaks, no new Ebola cases have been identified which is 42 days in length (i.e., twice the maximum incubation period for Ebola virus disease).
According to the WHO, the reason Ebola has been contained in Nigeria is due to a number of factors, including strong leadership, effective coordination of the response, first rate virology lab available at Lagos university, and experienced epidemiologists who expedited the early detection of cases and their rapid isolation.
Some key points noted by the WHO were:
- Dr Rui Vaz and the WHO country team of epidemiologists, clinicians, logisticians and administrators identified a number of specific lessons that may be useful for other countries facing their first imported Ebola case or preparing for one. They have also documented a large number of “best practices” for containing an Ebola outbreak quickly.
- The most critical factor is leadership and engagement from the head of state and the Minister of Health.
- Generous allocation of government funds and their quick disbursement helped as well.
- Partnership with the private sector brought in substantial resources to help scale up control measures.
- Health and government officials rallied communities to support containment measures.
- House-to-house information campaigns and messages on local radio stations, in local dialects, were used to explain the level of risk, effective personal preventive measures and the actions being taken for control.
The success of the containment makes it clear that Ebola, along with the other diseases plaguing Nigeria, can be controlled, regardless of the country. Dr Margaret Chan, the WHO Director-General said: