Alcelaphine herpesvirus 2

Alcelaphine herpesvirus 2 is a type of rhadinovirus that is believed to be responsible for causing hartebeest infections of malignant catarrhal fever [cite book | last = Fauquet | first = C | authorlink = | coauthors = J. Maniloff, U. Desselberger, L.A. Ball | title = Virus Taxonomy: Classification and Nomenclature of Viruses : Eighth Report of the International Committee on the Taxonomy of Viruses | publisher = Academic Press | date = 2005 | location = | pages = | url = | doi = | id = | isbn = 0122499514 ] .

Clinical Definition

Distantly related to human herpes, this virus type is comprised of a series of double strand sequences of up to 100 gene segements, aligned along a long chromosome surrounded by terminal DNA segments. The effect of the virus is to casue nasal discharge, a high fever, filmed over eyes, failures of the lymphatic system, inflammation of various mucus membranes, and occasioanly necrosis of the upper digestive system. Very advanced cases show signs of decay of the nervous system. Occasionally, lesions, arthritis, and digestive problems such as diarrhea have been observed. [Adams, S.W., and Mutt, LM. 1990. Characterization of envelope proteins of alcelaphine herpesvirus 1 & 2. Journal of. Virology, 64:3382-3390.]

Etiology

The agent of MCF in hartebeests, it's related to other variants that strike down antelopes. It was isolated in 1960 and is believed to be carried as reservoirs by goats, sheep, and other domestic animals. There are variants that have affected deer, gnu, and other captive species in zoos around the world.

Range

All species of African wildebeest and hartbeest can be infected or at least carry this virus. [Katz, J 991. Molecular diagnosis of alcelaphine herpesvirus (malignant catarrhal fever) infections by nested amplification of viral DNA in bovine blood buffy coat specimens. Journal of Vetenary. Diagnostic. Investigation., 3:193-198.] There is no direct evidence that other African wild variants like addax can be hosts, but research is ongoing [T. Vikoren, H. Li, A. Lillehaug, C. M. Jonassen, I. Bockerman, and K. Handeland MALIGNANT CATARRHAL FEVER IN FREE-RANGING CERVIDS ASSOCIATED WITH OVHV-2 AND CPHV-2 DNA J. Wildl. Dis., October 1, 2006; 42(4): 797 - 807] . The alcelaphine antelope affecting form is primarily found in Africa, in the natural habitat of wildebeest, hartebeest, and topi [ cite journal|title=Malignant Catarrhal Fever-Like Disease in Barbary Red Deer (Cervus elaphus barbarus) Naturally Infected with a Virus Resembling Alcelaphine Herpesvirus 2{dagger}|journal=Journal of Clinical Microbiology|date=|first=Robert|last=Klieforth|coauthors=Gabriel Maalouf, Ilse Stalis, Karen Terio|volume=40|issue=9|pages=3381-3390|id= |url=http://jcm.asm.org/cgi/content/abstract/40/9/3381|format=|accessdate=2008-09-15 ] . It has also occurred in zoos and wild animal parks that also kept wildebeest. The increasing popularity in North America of wild animal parks may spread it's range further.

Transmission, clinical effects, and morbidity

Alcelaphine herpesvirus 2 is primarily transmitted by nasal emissions, by contact with water, flood, feces, or close contact. It can be destroyed by prolonged exposure to sunlight, but has a very long incubation period and thus may have a long period of time to infect other animals. There are three forms usually seen. The first a nasal form with fever, nasal inflammation and digestive problems that is very mild and only lasts a few days. The second is a more severe form that involves fever, diarrhea, heavy nasal discharge, and lymph system failure, with a morbidity of 28 percent. The so-called "head and eye" form is the most lethal and serious form, which results in all known effects and central nervous system damage, predated by nervous shakes and eventually muscular failure. Morbidity in some cases is as high as 90 percent.

Vaccination

As the primary infected strains of animals are wild and free range animals, vaccination programs have been largely ineffective.

References