The family Bunyaviridae contains five genera:  Bunyavirus, Phlebovirus, Nairovirus, and Hantavirus, and Tospovirus. One of the largest viral families with over 300 viruses, the Bunyaviruses have presented a significant challenge to taxonomists.  The viruses have similar morphological features.  Ranging g form 80 to 120 nm in size the viral particles are spherical or pleomorphic.  They are enveloped viruses with a single stranded RNA  genome of mostly negative polarity that is divided into three segments.  Currently molecular genomic features and proteins are used to define the Bunyavirus genera and antigenic data  are used to separate the viruses within each genus.
 
The Bunyavirus Genus
    Named after the Bunyamwera virus ((Bunyamwera, locality in Uganda), Almost all of the over 150 viruses in this family are transmitted by mosquitos but have a wide variety of vertebrate hosts.  Within this genus, the California Serogroup Viruses are those that most commonly affect humans.  Causing a   febrile type illnesses that can range from encephalitis to flu-like syndromes, La Crosse virus,  Tahyna virus and snowshoe hare viruses have been most extensively studied.

The Hantavirus Genus
    The hantaviruses (named after the Hantaan virus) are enzootic viruses of wild rodents that cause persistent infections in their natural hosts.  Associated with hemorrhagic fevers and spread through the inhalation of aerosolized viral particles from fecal material, the viruses of this group have  been increasingly the subject of accelerated  research..  Viruses such as the Hantaan, the Sin Nombre Virus (the Four Corner's Virus), Prospect Hill, Puumala, and Seoul viruses  are found in this genus.

The Nairovirus Genus
    The Nairoviruses are tick borne viruses which are subdivided into several serogroups.  Crimean-Congo hemorrhagic fever virus is the most medically significant  member of this genus and the best studied representative.

The Phlebovirus Genus
    The Phlebovirus genus comprises over 50 viruses which are transmitted by mosquitoes or phlebotomine flies.  Rift Valley fever virus and sandfly fever virus are the most medically important agents which have been the greatest focus of study.

The Tospovirus Genus
    The tospoviruses are the only members of the family that infect plants rather than animals.  Transmitted by thrips, the viruses have only recently been recognized as Bunyaviruses.