Bunyaviruses represent the largest group of RNA viruses, and are the causative agent of a variety of febrile and hemorrhagic illnesses. Originally characterized as a single serotype in Africa, the number of described bunyaviruses now exceeds over 500, with its presence detected around the world. These predominantly tri-segmented, single-stranded RNA viruses are transmitted primarily through arthropod and rodent vectors, and can infect a wide variety of animal and plants. Although encoding for a small number of proteins, these viruses can inflict potentially fatal disease outcomes, and have even developed strategies to suppress the innate antiviral immune mechanisms of the infected host. This short review will attempt to provide an overall description of the order Bunyavirales, describing the mechanisms behind their infection, replication and their evasion of the host immune response. Furthermore, the historical context of these virus will be presented, starting from their original discovery almost 80 years ago, to the most recent research pertaining to viral replication and host immune response.

Henipaviruses are single-stranded RNA viruses that have been shown to be virulent in several species including humans, pigs, horses, and rodents. Isolated nearly 30 years ago, these viruses have been shown to be of particular concern to public health, as at least two members (Nipah and Hendra viruses) are highly virulent, as well as zoonotic, and are thus classified as BSL4 pathogens. Although only 5 members of this genus have been isolated and characterized, metagenomics analysis using animal fluids and tissues has demonstrated the existence of other novel henipaviruses, suggesting a far greater degree of phylogenetic diversity than currently known. Using a variety of molecular biology techniques, it has been shown that these viruses exhibit varying degrees of tropism, on a species, organ/tissue, and cellular level. This review will attempt to provide a general overview of our current understanding of henipaviruses, with particular emphasis on viral tropism.