Ebola

Ebola

Ebola virus disease is the name for the human disease which may be caused by any of the four known ebolaviruses. These four viruses are: Bundibugyo virus , Ebola virus , Sudan virus , and Taï Forest virus...

 outbreaks have been restricted to Africa, with the exception of Reston ebolavirus. The International Committee on Taxonomy of Viruses

International Committee on Taxonomy of Viruses

The International Committee on Taxonomy of Viruses is a committee which authorizes and organizes the taxonomic classification of viruses. They have developed a universal taxonomic scheme for viruses and aim to describe all the viruses of living organisms. Members of the committee are considered to...

 currently recognizes four species of the Ebola: Zaire virus (ZEBOV), Sudan ebolavirus (SEBOV), Reston ebolavirus (REBOV), and Cote d'Ivoire ebolavirus (CIEBOV). One additional species or type of Ebola is often recognized by the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) as Bundibugyo ebolavirus or Ebola-Bundibugyo, following the outbreak in Uganda in 2007.

Transmission between natural reservoirs and humans is rare, and outbreaks are often traceable to a single index case where an individual has handled the carcass of a gorilla

Gorilla

Gorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies...

, chimpanzee

Chimpanzee

Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...

, or duiker

Duiker

A duiker is any of about 21 small to medium-sized antelope species from the subfamily Cephalophinae native to Sub-Saharan Africa.Duikers are shy and elusive creatures with a fondness for dense cover; most are forest dwellers and even the species living in more open areas are quick to disappear...

. The virus then spreads person-to-person, especially within families, hospitals, and during some mortuary rituals where contact among individuals becomes more likely. Before outbreaks are confirmed in areas of weak surveillance on the local or regional levels, Ebola is often mistaken for malaria

Malaria

Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

, typhoid fever

Typhoid fever

Typhoid fever, also known as Typhoid, is a common worldwide bacterial disease, transmitted by the ingestion of food or water contaminated with the feces of an infected person, which contain the bacterium Salmonella enterica, serovar Typhi...

, dysentery

Dysentery

Dysentery is an inflammatory disorder of the intestine, especially of the colon, that results in severe diarrhea containing mucus and/or blood in the faeces with fever and abdominal pain. If left untreated, dysentery can be fatal.There are differences between dysentery and normal bloody diarrhoea...

, influenza

Influenza

Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...

, or various bacterial infections

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 which may be endemic to the region. Learning from failed responses, such as that to the 2000 Uganda outbreak, public health measures including the WHO's Global Outbreak and Response Network were instituted in areas at high risk. Field laboratories were established in order to confirm cases, instead of shipping samples to South Africa.

The United States Centers for Disease Control and Prevention

Centers for Disease Control and Prevention

The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...

Special Pathogens Branch charter to study highly infectious viruses, many causing hemorrhagic fevers, has historically endowed it to closely follow Ebola outbreaks. Compiling scientific journals and public health announcements, the following list is from Known Cases and Outbreaks of Ebola Hemorrhagic Fever, in Chronological Order:

Year	Country	Type	Reported human cases	Reported deaths	% Fatality	Description
1976	Zaire (Democratic Republic of Congo)	ZEBOV	318	280	88%	Occurred in Yambuku and surrounding area. Disease was spread by close personal contact and by use of contaminated needles and syringes in hospitals/clinics. This outbreak was the first recognition of the disease.
1976	Sudan	SEBOV	284	151	53%	Occurred in Nzara, Maridi and the surrounding area. Disease was spread mainly through close personal contact within hospitals. Many medical care personnel were infected.
1976	England	SEBOV	1	0	0%	Laboratory infection by accidental stick of contaminated needle.
1977	Zaire	ZEBOV	1	1	100%	Noted retrospectively in the village of Tandala.
1979	Sudan	SEBOV	34	22	65%	Occurred in Nzara, Maridi. Recurrent outbreak at the same site as the 1976 Sudan epidemic.
1989	USA	REBOV	0	0	0%	REBOV was introduced into quarantine facilities in Virginia and Pennsylvania by monkeys imported from the Philippines.
1990	USA	REBOV	4 (asymptomatic)	0	0%	REBOV was introduced once again into quarantine facilities in Virginia and Texas by monkeys imported from the Philippines. Four humans developed antibodies but did not get sick.
1989-1990	Philippines	REBOV	3 (asymptomatic)	0	0%	High mortality among cynomolgus macaques in a primate facility responsible for exporting animals in the USA. Three workers in the animal facility developed antibodies but did not get sick.
1992	Italy	REBOV	0	0	0%	REBOV was introduced into quarantine facilities in Siena by monkeys imported from the same export facility in the Philippines that was involved in the episodes in the United States. No humans were infected.
1994	Gabon	ZEBOV	52	31	60%	Occurred in Mékouka and other gold-mining camps deep in the rain forest. Initially thought to be yellow fever; identified as Ebola hemorrhagic fever in 1995.
1994	Ivory Coast	CIEBOV	1	0	0%	Scientist became ill after conducting an autopsy on a wild chimpanzee in the Tai Forest. The patient was treated in Switzerland.
1995	Democratic Republic of Congo (formerly Zaire)	ZEBOV	315	250	81%	Occurred in Kikwit and surrounding area. Traced to index case-patient who worked in forest adjoining the city. Epidemic spread through families and hospitals.
1996 Jan-Apr	Gabon	ZEBOV	37	21	57%	Occurred in Mayibout area. A chimpanzee found dead in the forest was eaten by people hunting for food. Nineteen people who were involved in the butchery of the animal became ill; other cases occurred in family members.
1996-1997 Jul-Jan	Gabon	ZEBOV	60	45	74%	Occurred in Booué area with transport of patients to Libreville. Index case-patient was a hunter who lived in a forest camp. Disease was spread by close contact with infected persons. A dead chimpanzee found in the forest at the time was determined to be infected.
1996	South Africa	ZEBOV	2	1	50%	A medical professional traveled from Gabon to Johannesburg, South Africa, after having treated Ebola virus-infected patients and thus having been exposed to the virus. He was hospitalized, and a nurse who took care of him became infected and died.
1996	USA	REBOV	0	0	0%	REBOV was introduced into a quarantine facility in Texas by monkeys imported from the Philippines. No human infections were identified.
1996	Philippines	REBOV	0	0	0%	REBOV was identified in a monkey export facility in the Philippines. No human infections were identified.
2000-2001	Uganda	SEBOV	425	224	53%	Occurred in Gulu, Masindi, and Mbarara districts of Uganda. The three most important risks associated with Ebola virus infection were attending funerals of Ebola hemorrhagic fever case-patients, having contact with case-patients in one's family, and providing medical care to Ebola case-patients without using adequate personal protective measures.
2001-2002 Oct-Mar	Gabon	ZEBOV	65	53	82%	Outbreak occurred over the border of Gabon and the Republic of the Congo.
2001-2002 Oct-Mar	Republic of Congo	ZEBOV	57	43	75%	Outbreak occurred over the border of Gabon and the Republic of the Congo. This was the first time that Ebola hemorrhagic fever was reported in the Republic of the Congo.
2002-2003 Dec-Apr	Republic of Congo	ZEBOV	143	128	89%	Outbreak occurred in the districts of Mbomo and Kéllé in Cuvette Ouest Département.
2003 Nov-Dec	Republic of Congo	ZEBOV	35	29	83%	Outbreak occurred in Mbomo and Mbandza villages located in Mbomo district, Cuvette Ouest Département.
2004	Sudan	SEBOV	17	7	41%	Outbreak occurred in Yambio county of southern Sudan. This outbreak was concurrent with an outbreak of measles in the same area, and several suspected EHF cases were later reclassified as measles cases.
2007	Democratic Republic of Congo	ZEBOV	264	187	71%	Outbreak occurred in Kasai Occidental Province. The outbreak was declared over on November 20. Last confirmed case on October 4 and last death on October 10.
2007-2008 Dec-Jan	Uganda	Bundibugyo ebolavirus	149	37	25%	Outbreak occurred in Bundibugyo District in western Uganda. First reported occurrence of a new strain.
2008 Nov	Philippines	REBOV	6 (asymptomatic)	0	0%	First known occurrence of REBOV in pigs. Strain closely similar to earlier strains. Six workers from the pig farm and slaughterhouse developed antibodies but did not become sick.
2008-2009 Dec-Feb	Democratic Republic of Congo	ZEBOV	32	14	47%	Outbreak occurred in the Mweka and Luebo health zones of the Province of Kasai Occidental.