A Model of Superinfection of Virus-Infected Zebrafish Larvae: Increased Susceptibility to Bacteria Associated With Neutrophil Death.

Enhanced susceptibility to bacterial infection in the days following an acute virus infection such as flu is a major clinical problem. Mouse models have provided major advances in understanding viral-bacterial superinfections, yet interactions of the anti-viral and anti-bacterial responses remain elusive. Here, we have exploited the transparency of zebrafish to study how viral infections can pave the way for bacterial co-infections.

Chikungunya Virus Overcomes Polyamine Depletion by Mutation of nsP1 and the Opal Stop Codon To Confer Enhanced Replication and Fitness.

Polyamines, which are small positively charge molecules present in all cells, play important roles in the replication of DNA and RNA viruses. Chikungunya virus (CHIKV) relies on polyamines for translation of the viral genome upon viral entry, and pharmacological depletion of polyamines limits viral replication. However, the potential development of antiviral resistance necessitates a better understanding of how polyamines function and can be targeted via compounds that alter polyamine levels.

Imaging of viral neuroinvasion in the zebrafish reveals that Sindbis and chikungunya viruses favour different entry routes.

Alphaviruses, such as chikungunya virus (CHIKV) and Sindbis virus (SINV), are vector-borne pathogens that cause acute illnesses in humans and are sometimes associated with neuropathies, especially in infants and elderly patients. Little is known about their mechanism of entry into the central nervous system (CNS), even for SINV, which has been used extensively as a model for viral encephalopathies. We previously established a CHIKV infection model in the optically transparent zebrafish larva; here we describe a new SINV infection model in this host.

Interferon-Induced Spermidine-Spermine Acetyltransferase and Polyamine Depletion Restrict Zika and Chikungunya Viruses.

Polyamines are small, positively charged molecules derived from ornithine and synthesized through an intricately regulated enzymatic pathway. Within cells, they are abundant and play several roles in diverse processes. We find that polyamines are required for the life cycle of the RNA viruses chikungunya virus (CHIKV) and Zika virus (ZIKV).

The antiviral innate immune response in fish: evolution and conservation of the IFN system.

Innate immunity constitutes the first line of the host defense after pathogen invasion. Viruses trigger the expression of interferons (IFNs). These master antiviral cytokines induce in turn a large number of interferon-stimulated genes, which possess diverse effector and regulatory functions.