Lake Chad Virus

Lake Chad is a shallow, closed basin lake located in Sub-Saharan Africa with four countries (Chad, Cameroon, Niger and Nigeria) surrounding it. The lake has large areas of swamp and reedbeds. It is home to many species of migratory birds. Like the Dutch Wadden Sea, Lake Chad is recognized as a wetland of international significance.

The family Orthomyxoviridae seems to be receiving new family members at an alarming rate. Not long ago it comprised of only three genera: Influenzavirus A, Influenzavirus B and Influenzavirus C. New members are the Isavirus, Thogotoviruses and Quarjaviruses.

The genus Isavirus (Infectious Salmon Anemia Virus) has only one member, which causes severe anemia in multiple farmed fish strains and is a therefore significant commercial problem. Thogotoviruses consist of five different but related viruses: Thogoto virus, Dhori virus, Batken virus, Araguari virus[1] and Jos Virus. Finally, the Quarjaviruses[2] also consist of three separate viruses: Quaranfil virus, Johnston Atol virus and Lake Chad virus.
The hosts of both Thogotoviruses and Quarjaviruses are thought to be ticks, birds and mammals, including humans. Lake Chad Virus was first isolated from a masked weaver bird (Ploceus vitellinus), collected at Lake Chad in 1969.

At the moment, not much is known about these novel viruses but a somewhat crude test revealed that Lake Chad Virus is lethal to newborn mice after these mice were inoculated with the virus.

What we have here then, is a virus that has been isolated from just one species of bird, the masked weaver bird, in a remote area of Africa, Lake Chad. But this expanse of water is also home of many species of migratory birds. Suppose some of these birds are infected with the Lake Chad Virus when they fly back to northern Europe to breed...

[1] Da Silva et al: Araguari virus, a new member of the family Orthomyxoviridae: serologic, ultrastructural, and molecular characterization in American Journal of Tropical Medicine and Hygiene - 2005 
[2] Presti et al: Quaranfil, Johnston Atoll, and Lake Chad viruses are novel members of the family Orthomyxoviridae in Journal of Virology - 2009

No comments:

Post a Comment