Arbovirus infections

Arboviruses (arthropod-borne viruses) represent a large group of medically and veterinary important RNA viruses circulating between vertebrate hosts and arthropod vectors. The latter include hard ticks or dipteran insects such as mosquitoes, black flies, sandflies, and biting midges. An exception is the transmission of African swine fever virus, a DNA virus, by soft ticks.  All other arboviruses are RNA viruses belonging to the Flaviviridae, Togaviridae, Bunyavirales, Reoviridae, or Rhabdoviridae. Over 500 virus species have been designated as arboviruses.  

Globally, the medically most relevant mosquito-borne arboviruses are dengue (four serotypes), Zika, chikungunya, yellow fever, West Nile, and Japanese encephalitis viruses, which all belong to the Flaviviridae with the exception of chikungunya virus (Togaviridae). Important tick-borne viruses are tick-borne encephalitis virus/Powassan virus and Crimean-Congo hemorrhagic fever virus. Blue tongue virus transmitted by biting midges, vesicular stomatitis virus transmitted by black flies, and the mosquito-borne Rift Valley fever virus primarily infect sheep and cattle, while the latter two viruses are also pathogenic for humans.     

Arbovirus-vector-host interactions can be highly species specific. Importantly, both the arthropod vector and the vertebrate host need to be productively infected with an arbovirus to maintain its transmission cycle. The vertebrate host uses its innate and adaptive immune systems to sense and respond to an arbovirus infection while the arthropod vector is utilizing its innate immune pathways and RNA interference mechanism. Arboviruses must have developed unique strategies to cope with the immune responses in both cellular environments. 
 
Current climate change scenarios forecast a further expansion of the tropical regions around the world going hand-in-hand with the continuous spread of vector-borne diseases including arboviruses. Due to expanding human trade and traffic, arboviruses that were largely unaccounted for as long as they remained in their sylvatic transmission cycles may suddenly enter urban transmission cycles and cause novel disease outbreaks among human or animal populations.   

Only about a handful of vaccines are readily available to prevent human infections with arboviruses such as yellow fever virus, Japanese encephalitis virus, or tick-borne encephalitis virus. Thus, arbovirus control primarily relies on vector control measures. In regard to mosquito control, these typically involve the use of insecticide treated bednets and window curtains, as well as residual insecticide applications. Novel mosquito control strategies are based on genetic population control, and the generation of genetically engineered mosquitoes that are refractory to arboviruses.      

This brief introduction illustrates the diversity of arboviruses and the wide range of aspects on arbovirus research. In this Special Collection, we invite all authors to submit their novel work on arbovirus research with emphasis given to the following topics:       

• Emerging arboviruses
• Arbovirus-vector-host interactions
• Molecular biology of arboviruses
• Arboviral pathogenicity 
• Novel arbovirus control strategies