FILOVIRIDAE FAMILY

Filoviridae family consists of viruses generally known as Filoviruses. Filoviruses have a ss(-)RNA genome. They are enveloped viruses because they have envelope. Viruses in this family are pleomorphic in nature, and thus have varying shapes.  They actually appear in very long and thread-like structure. The length of Filoviruses can be above 10,000 nm in size due to the variability of the pathogen; and they measure about 80 nm in diameter. But the normal length of Filoviruses is between 800-1000 nm. The Filoviridae family is comprised of only two genera of viruses viz: Marburgvirus and Ebolavirus, both of which cause haemorrhagic fevers in humans. The viruses in each of these genera can generally be called Marburg virus and Ebola virus as the case may be; and they are usually named according to the geographic region where they cause a disease outbreak. Marburg virus is the causative agent of Marburg disease, a type of haemorrhagic fever generally known as Marburg haemorrhagic fever (MHF). And Marburg virus is only a single-type virus i.e. it is the only virus in the genus Marburgvirus.

MHF has an incubation period of 5-10 days; and the disease only occurs in Africa. Maculopapular rash, nausea, vomiting, chest pain, diarrhea, abdominal pain and massive haemorrhagic and multiple organ dysfunction or failure are some of the clinical symptoms of the disease. Marburg virus infects humans and other primates; and human-to-human transmission of the disease is possible. Ebola virus is the causative agent of ebola disease, a severe haemorrhagic fever that occurs in parts of Africa and the Philippines. There are four subtypes of ebola virus that have been recognized to infect humans; and these are: Zaire ebolavirus (ZEBOV), Sudan ebolavirus (SEBOV), Cote d’Ivoire ebolavirus (CIEBOV) and Reston ebola virus (which occurs only in the Philippines). ZEBOV, SEBOV and CIEBOV infect humans while CIEBOV infect monkeys in the Philippines.

The incubation period of ebola disease is 2-21 days; and the disease is characterized clinically by high fever, joint pains, muscle aches, sore throat, diarrhea, headache and vomiting. A maculopapular rash which appears all over the body; and severe internal and external bleeding is also associated with ebolavirus infection. Filoviruses (i.e. viruses in the Filoviridae family) are primate-borne viruses that are usually transmitted to humans who come in contact with excreta or body secretions of the animals or primates that serve as natural host for these viruses. Filoviruses are of biosafety and biosecurity concern because of the bioterrorism threat they pose; and thus viruses in the Filoviridae family are classified as biosafety level 4 (BSL-4) pathogens.

SELECTED REFERENCES

Acheson N.H (2011). Fundamentals of Molecular Virology. Second edition. John Wiley and Sons Limited, West Sussex, United Kingdom.

Ahmad K (2002). Norwalk-like virus attacks troops in Afghanistan. Lancet Infect Dis, 2:391.

Alan J. Cann (2005). Principles of Molecular Virology. 4th edition. Elsevier Academic Press,   Burlington, MA, USA.

Alba R, Bosch A and Chillon M (2005). Gutless adenovirus: last-generation adenovirus for gene therapy. Gene Ther, Suppl 12:S18-S27.

Alberts B, Bray D, Johnson A, Lewis J, Raff M, Roberts K and Walter P (1998). Essential Cell Biology: An Introduction to the Molecular Biology of the Cell. Third edition. Garland Publishing Inc., New York.

Balows A, Hausler W, Herrmann K.L, Isenberg H.D and Shadomy H.J (1991). Manual of clinical microbiology. 5th ed. American Society of Microbiology Press, USA.

Barrett   J.T (1998).  Microbiology and Immunology Concepts.  Philadelphia,   PA: Lippincott-Raven Publishers. USA.

Leave a Reply

Your email address will not be published. Required fields are marked *