Wednesday, 22 October 2014

Ebola Virus

Ebola virus disease is a rare fetal and severe infectious disease that could lead to death if untreated. Its formal name was ebola hemorrhage fever. This infection was first identified in 1976 in Sudan and Democratic Republic of Congo.

Ebola Virus (Photo credit: Flickr)

Epidemiology:

The first two outbreaks of ebola virus disease were started in 1976. The third and current (2014) outbreak is considered as the most complex and devastating one. Nearly more than 9000 cases of EVD has been reported to CDC and more than 4000 patients have been died.

Affected counties:

This current outbreak has targeted several African countries including;
  • Guinea
  • Nigeria
  • Liberia
  • Sierra Leon
  • Senegal.

The most affected country is Liberia as maximum number of EVD cases has been reported from this country.  Now World Health Organization (WHO) has given Ebola Free Status to Niegeria (October, 2014).   

Microbiology of Ebola Virus:

Ebola virus belongs to Filovirdiea family and comprises of five species namely;
  1. Zaire ebola virus
  2. Reston ebola virus
  3. Sudan ebola virus
  4. Tair forest ebola virus
  5. Budibugo ebola virus

The most notorious specie that has targeted humans in recent outbreak (2014 ebloa virus outbreak) is Zaire.
It is believed that bats are most appropriate and suitable host of ebola virus. It should be remembered that ebola virus disease was spread from animals to humans.

Sign and symptoms:

The incubation period of ebola virus is 2 to 21 days but average period is 8 to 10 days.
According to WHO, Patients suffering from ebola infection could experience following sign and symptoms;
  • Fever
  • Headache
  • Sore throat
  • Vomiting
  • Stomach pain
  • Muscle pain
  • Rashes
  • Diarrhea
  • Bleeding and etc.

Transmission:

Since there is no treatment or therapy that is approved by U.S Food and Drug Administration (FDA) so major emphasis should be done to prevent this infection by blocking its transmission in humans  either from animals to human transmission or human to human transmission. Ebola virus can transmit via direct contact with;
  • Blood
  • Body secretions
  • Different fluids of body
  • Surface
  • Materials (contaminated clothing)

Diagnosis:

It is difficult to diagnose patients suffering from ebola virus as there are other diseases in which patients also experience same type of sign and symptoms. Following tests are being used to diagnose this infection.
  • Reverse transcriptase polymerase chain reaction (RT PCR)
  • ELISA
  • Electron microscopy
  • Antigen capture detection test
  • Serum neutralizing test
  • Virus isolation by culture test

In order to detect any abnormality in liver following tests can also be done;
  • ALT
  • AST
  • Bilirubin
  • SGOT/SGPT.

Treatment:

Currently there is FDA approved treatment available to treat and manage this dangerous infection but efforts are being made to discover such chemical molecules that could treat and prevent its risk to humans. Patients usually receive only supportive treatment which includes;
  • IV administration of fluids such as electrolytes;
  • Antibiotics to treat any infection;
  • Drugs to maintain blood pressure;
  • Normalizing oxygen status.

Vaccination:

There is no vaccination to prevent this devastating disease currently but researchers are attempting to initiate clinical trials by using some drugs.

References:
  1. World Health Organization (WHO), Ebola Virus, http://www.who.int/mediacentre/factsheets/fs103/en/, (Accessed on 22-10-2014)
  2. Center for Disease Control and Prevention (CDC), Ebola Virus, http://www.cdc.gov/vhf/ebola/about.html, (Accessed on 22-10-2014)
  3. Kuhn, Jens H.; Becker, Stephan; Ebihara, Hideki; Geisbert, Thomas W.; Johnson, Karl M.; Kawaoka, Yoshihiro; Lipkin, W. Ian; Negredo, Ana I et al. (2010)."Proposal for a revised taxonomy of the family Filoviridae: Classification, names of taxa and viruses, and virus abbreviations". Archives of Virology 155 (12): 2083–103
  4. Bowen, E. T. W.; Lloyd, G.; Harris, W. J.; Platt, G. S.; Baskerville, A.; Vella, E. E. (1977). "Viral haemorrhagic fever in southern Sudan and northern Zaire. Preliminary studies on the aetiological agent". Lancet 309 (8011): 571–3
  5. Klenk, H-D; Feldmann, H (editor) (2004). Ebola and Marburg Viruses: Molecular and Cellular Biology. Horizon Bioscience.
  6. Jenkins, G. M.; Rambaut, A; Pybus, O. G.; Holmes, E. C. (2002). "Rates of molecular evolution in RNA viruses: A quantitative phylogenetic analysis". Journal of Molecular Evolution 54 (2): 156–65 

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