Pandora of Ebola virus: are we ready?

Abstract

On 23 March 2014, the ministry of health of Guineanotified WHO of a rapidly spreading outbreak of Ebolavirus disease (EVD) in south-eastern forested areas, and4 days later, the disease was confirmed to be transmitted toConakry, the Capital of Guinea. The disease also rapidlyspread to Liberia, Nigeria and Sierra Leone. As of 27 July2014, the cumulative number of confirmed (909), probable(276) and suspect (138) EVD cases in the above fourcountries reached 1,323, including 729 deaths (with thedeath rate of 55.1 %) (http://www.who.int/csr/don/2014_07_31_ebola/en/). This is the largest outbreak of EVD untilnow and the first time the disease detected in West Africa.EVD, previously known as Ebola haemorrhagic fever, isa severe, often fatal illness, with very high case fatality rateof up to 90 %. The previous EVD outbreaks in Uganda(epidemic from October of 2000 to February of 2001) andin Gabon and the Republic of the Congo (outbreak fromDecember of 2001 to March of 2002) were also persistedfor several months. The outbreak of EVD in West Africaseemed out of control although WHO has coordinated withdifferent organizations and countries for containing thisdisease [1]. For the last four months, the EVD epidemic hasspread to the nearby countries and new cases and newdeaths were reported almost every day. Until 6 August2014, there were 14 outbreaks of EVD and three singlecase reports in the world, resulting in 4,178 cases ofinfection and 2,564 deaths, with death rate from 41 %–88 %(excluding the single case report, Fig. 1).Ebola was first reported in 1976 when there were out-breaks in Sudan and Democratic Republic of Congo [2, 3].The genus Ebolavirus belongs to the Filoviridae family(filovirus), which also includes genus Marburgvirus andgenus Cuevavirus. There are five distinct species in thegenus Ebolavirus, including Bundibugyo ebolavirus; Zaireebolavirus; Sudan ebolavirus; Reston ebolavirus; and Tai¨Forest ebolavirus. The first three species have been asso-ciated with large EVD outbreaks in Africa, whereas thelatter two have not. Samples taken from patients of thisoutbreak have been confirmed to be caused by a strain ofebolavirus closely related (98 %) to the Zaire one. Theebolavirus should be operated under biosafety level IVlaboratory. Even in this high-level containment laboratory,there were still accidentally laboratory-acquired infectionsreported [4, 5].Fruit bats are believed to be the natural hosts of Ebolavirus [6]. The wild animals (monkeys or apes) could becontracted the virus from contacting with bat saliva orfaeces. Humans could be transmitted from contacting withinfected bats or wild animals. The EVD can be transmittedfrom person to person by direct contact. More and moreevidence showed that pigs might be the host of ebolavirus[7, 8]. From the distribution of fruit bats (http://www.who.int/csr/disease/ebola/en/#), the potential riskregion of EVD not only is limited to Africa but alsoincludes wide range of America, southern Asia and part ofAustralia.Since there is no effective antiviral drugs and specificvaccine for treating and preventing EVD, we all need toprepare for early recognition of EVD and special pre-ventive countermeasures should be taken for the suspectedpatients. Rapid and specific screening assays should bedeveloped for early diagnosis of EVD; however, the clin-ical doctors should pay close attention to the suspectedpatients, especially for those with travel history in theepidemic regions. Hospitals need to prepare to protect