Ebola Virus Outbreak, 2014

Dr. Md. Shakeel WaezAsst. Professor (Medicine)

Chittagong Medical College

Epidemiology

• Ebola first appeared in 1976.

• 2 simultaneous outbreaks in Nzara, Sudan and in Yambuku, Democratic Republic of Congo.

• The latter was in a village situated near the Ebola River, from which the disease takes its name.

• Formerly known as Ebola haemorrhagic fever.

History

The disease typically occurs in outbreaks in tropical regions of Sub-Saharan Africa

The countries which suffered frequent Ebola outbreaks includes Democratic Republic of Congo, Sudan, Gabon, Ivory coast, Uganda.

The largest outbreak is the ongoing 2014 West Africa Ebola outbreak, which is affecting Guinea, Sierra Leone, Liberia, and Nigeria.

Geographic distribution

Epidemiological determinants

Ebola virus is a zoonotic Pathogen. Genus: Ebola virus

Family: Filoviradae

Order: MononegaviratesFig. Ebola virus

Genus ebola virus comprises 5 distinct species: Bundibugyo ebolavirus (BDBV)

Zaire ebolavirus (EBOV)

Reston ebolavirus (RESTV)

Sudan ebolavirus (SUDV)

Taï Forest ebolavirus (TAFV).

BDBV, EBOV, and SUDV have been associated with large EVD outbreaks in Africa, whereas RESTV and TAFV have not.

Host Factors

Natural Hosts:

• Not known yet definitely.

• In Africa, fruit bats are considered most likely natural hosts for Ebola virus. As a result, the geographic distribution of Ebola viruses may overlap with the range of the fruit bats.

Fig. Fruit bat

Animal to human transmission:

Saliva of fruit bats contains the virus Land mammals and non human primates get infected by eating half eaten fruits Human get infected when they come in close contact with infected animals

Mode of Transmission

Human to human transmission:

Direct contact with blood, secretion, organs or other body fluids of infected people.

Indirect contact with environments contaminated with such fluids.

Health care workers have frequently been infected while treating patients with EVD.

Mode of Transmission

Human to human transmission

Year Country Cases Death

1976 Congo 318 280

1995 Congo 315 254

2000 Uganda 425 224

2003 Congo 143 128

2007 Congo & Uganda

413 224

2012 Congo 57 28

Major Ebola Outbreaks

Country Cases Death

Guinea 735 415

Liberia 1192 672

Nigeria 17 6

Sierraleone 913 410

Total 2757 1504

2014 Outbreak (Updated 20/08/2014)