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Rift Valley Fever virus (RVFV) is a zoonotic mosquito-borne virus that belongs to the Phenuiviridae family. Infections in animal herds cause abortion storms, high mortality rates in neonates, and mild to severe symptoms. Infected animals can also transmit the virus to people, particularly people who live or work in close contact with livestock. There is currently an ongoing effort to produce safe and efficacious veterinary vaccines against RVFV in livestock to protect against both primary infection in animals and zoonotic infections in people. To test the efficacy of these vaccines it is essential to have a reliable challenge model in relevant target species, including ruminants. In this study we evaluated three routes of inoculation (intranasal, intradermal and a combination of routes) in Holstein cattle using an infectious dose of 107 pfu/ml and a virus strain from the 2006–2007 outbreak in Kenya and Sudan. Our results demonstrated that all routes of inoculation were effective at producing viremia in all animals; however, the intranasal route induced the highest levels and longest duration of viremia, the most noticeable clinical signs, and the most widespread infection of tissues. We therefore recommend using the intranasal inoculation for future vaccine and challenge studies.

Rift Valley fever virus (RVFV) is a zoonotic arbovirus of the Phenuiviridae family. Infection causes abortions in pregnant animals, high mortality in neonate animals, and mild to severe symptoms in both people and animals. There is currently an ongoing effort to produce safe and efficacious veterinary vaccines against RVFV in livestock to protect against both primary infection in animals and zoonotic infections in people. To test the efficacy of these vaccines, it is essential to have a reliable challenge model in relevant target species, including ruminants. We evaluated two goat breeds (Nubian and LaMancha), three routes of inoculation (intranasal, mosquito-primed subcutaneous, and subcutaneous) using an infectious dose of 107 pfu/mL, a virus strain from the 2006&ndash, 2007 Kenyan/Sudan outbreak and compared the effect of using virus stocks produced in either mammalian or mosquito cells. Our results demonstrated that the highest and longest viremia titers were achieved in Nubian goats. The Nubian breed was also efficient at producing clinical signs, consistent viremia (peak viremia: 1.2 &times, 103&ndash, 1.0 &times, 105 pfu/mL serum), nasal and oral shedding of viral RNA (1.5 &times, 101&ndash, 8 &times, 106 genome copies/swab), a systemic infection of tissues, and robust antibody responses regardless of the inoculation route. The Nubian goat breed and a needle-free intranasal inoculation technique could both be utilized in future vaccine and challenge studies. These studies are important for preventing the spread and outbreak of zoonotic viruses like RVFV and are supported by the Canadian-led BSL4ZNet network.

Zika virus (ZIKV) is an emerging pathogen causally associated with serious sequelae in fetuses, inducing fetal microcephaly and other neurodevelopment defects. ZIKV is primarily transmitted by mosquitoes, but can persist in human semen and sperm, and sexual transmission has been documented. Moreover, exposure of type-I interferon knockout mice to ZIKV results in severe damage to the testes, epididymis and sperm. Candidate ZIKV vaccines have shown protective efficacy in preclinical studies carried out in animal models, and several vaccines have entered clinical trials. Here, we report that administration of a synthetic DNA vaccine encoding ZIKV pre-membrane and envelope (prME) completely protects mice against ZIKV-associated damage to the testes and sperm and prevents viral persistence in the testes following challenge with a contemporary strain of ZIKV. These data suggest that DNA vaccination merits further investigation as a potential means to reduce ZIKV persistence in the male reproductive tract., Zika virus (ZIKV) can persist in human semen and sperm, which can result in sexual transmission. Here, Griffin et al. show that a DNA vaccine, expressing ZIKV pre-membrane and envelope proteins, protects mice from infection-associated damage to testes and sperm, and prevents viral persistence in testes.