Coltiviruses and Seadornaviruses

Abstract Coltiviruses and seadornaviruses are members of family Reoviridae , which encompasses alongside genera Coltivirus and Seadornavirus 13 other genera of viruses that can infect mammals, birds, aquatic animals, reptiles, insects, plants, fungi and protists. Coltiviruses are transmitted by hard ticks of the family Ixodidae , whereas seadornaviruses are mosquito‐borne. These viruses can infect humans, following the bite of adult‐infected female ticks or mosquitoes, causing febrile illnesses and are occasionally responsible for encephalitis. Coltiviruses are principally endemic in the northwestern parts of the USA and Canada and were also reported in European countries, including France and Germany. Antibodies to coltiviruses have also been identified from patients in the former Czechoslovakia and in South Korea. Seadornaviruses are principally endemic in the south east of Asia, although recent data showed that there has been an expansion of their distribution northwards, reaching the north‐western Chinese borders. Key concepts: Coltiviruses are transmitted by adult female tick (family Ixodidae ) bite and have animal reservoirs. Coltiviruses can infect humans causing febrile illnesses and can cause encephalitis in rare cases. Seadornaviruses are transmitted by mosquitoes and no animal reservoir is known to date. Seadornaviruses can infect animals and humans causing febrile illnesses and were reported to be responsible for cases of encephalitis. Coltiviruses show an evolutionary relationship to the turreted mycoreoviruses, aquareoviruses and orthoreoviruses. Seadornaviruses show an evolutionary relationship to the nonturreted rotaviruses. Coltiviruses seem to represent a missing link between turreted and nonturreted members of family Reoviridae. Differential diagnostic serological and molecular assays for coltiviruses and seadornaviruses are available. Structure of the viral particles of Banna virus shows striking similarities to that of the rotaviruses.