Bunyaviruses: Hantavirus and others

The Bunyaviridae family is the largest family of RNA viruses with more than 350 named isolates. Viruses in the family are divided into five genera (Orthobunyavirus, Phlebovirus, Nairovirus, Hantavirus, and Tospovirus) on the basis of serological, molecular, antigenic, and structural characteristics. The Bunyaviridae are a unique group of viruses whose members are able to infect invertebrates, vertebrates, and plants, and they can be found worldwide. Multiple members are significant pathogens with the ability to cause severe disease in humans, such as encephalitis, hepatitis, or hemorrhagic fever. Most bunyaviruses are spread through sylvatic transmission cycles between susceptible vertebrate hosts and hematophagous arthropods, including ticks, mosquitoes, and phlebotomine flies. Unique are the members of the Hantavirus genus, in that they are not infecting insect vectors but are maintained in nature through persistent infection of rodents. Human and animal pathogenic bunyaviruses can be found in four of the five genera, with tospoviruses being plant pathogens. The large family of bunyaviruses is a pool not only for many emerging and reemerging viruses, such as Rift Valley fever virus, Crimean-Congo hemorrhagic fever virus, and the hantaviruses, but also for recently emerged pathogens, such as the newly identified severe fever with thrombocytopenia syndrome and Heartland, Shuni, and Schmallenberg viruses. This chapter will discuss the most important human pathogens of the Orthobunyavirus, Phlebovirus, Nairovirus, and Hantavirus genera.