Immunogenicity and efficacy of Schmallenberg virus envelope glycoprotein subunit vaccines

The Schmallenberg virus (SBV) is an orthobunyavirus that causes abortions, stillbirths, and congenital defects in pregnant sheep and cattle. Inactivated or live attenuated vaccines have been developed in endemic countries, but there is still interest in the development of SBV vaccines that would allow Differentiating Infected from Vaccinated Animals (DIVA). Therefore, an attempt was made to develop novel DIVA-compatible SBV vaccines using SBV glycoproteins expressed in baculovirus. All vaccines and phosphate buffered saline (PBS) controls were prepared with adjuvant and administered subcutaneously to cattle at 6 month of age. The first trial included 2 groups of animals vaccinated with either carboxyl-terminus glycoprotein (Gc) or PBS and boosted after 2 weeks. In the second trial, 3 groups of cattle were administered either Gc, Gc and amino-terminus glycoprotein (Gn), or PBS with a booster vaccination after 3 weeks. The animals were challenged with SBV 9 days after the booster vaccination in the first study, and 3 weeks after the booster vaccination in the second study. Using a SBV Gc-specific enzyme-linked immunosorbent assay, antibodies were first detected in serum samples 14 days after the first vaccination in both trials, and peaked on days 7 and 9 after the booster in the first and second trials, respectively. Low titers of neutralizing antibodies were detected in serum from only 3/6 and 2/4 animals in the first and second trial, respectively, at 14 days after the first vaccination. The titers increased 2 to 3-fold after the booster vaccination. SBV-specific RNA was detected in the serum and selective tissues in all animals after SBV challenge independent of vaccination status. The SBV candidate vaccines neither prevented viremia nor conferred protection against SBV infection.

Schmallenberg (SVB): una nueva enfermedad en rumiantes / Schmallenberg (SVB): A New Disease in Ruminants / Schmallenberg (SVB): uma nova doença em ruminantes

La enfermedad de Schmallenberg (SBV) es una enfermedad viral emergente producida por un Orthobunyavirus que fue detectado por primera vez en bovinos a finales del 2011 en Alemania. Este afectaba de igual forma a ovinos y caprinos, y particularmente en estas especies generaba malformaciones congénitas en fetos de hembras preñadas, al igual que fiebre y baja en la producción de leche. Hoy en día, esta enfermedad ya se encuentra distribuida en varios países de Europa, y se sabe que en su transmisión están implicados vectores culicoides y mosquitos que, para las especies afectadas, desempeñan un papel importante en su epidemiología. Por otra parte, se ha establecido que la SBV no se puede considerar una zoonosis, ya que hasta el momento no hay suficientes evidencias científicas que demuestren lo contrario.

Schmallenberg (SBV) is an emerging viral disease caused by an Orthobunyavirus that was first detected in cattle at the end of 2011 in Germany. If similarly affected sheep and goats, which particularly generated congenital malformations in fetuses of pregnant females of these species, as well as fever and low milk production. Nowadays, this disease is already distributed in several European countries, and it is known that culicoides vectors and mosquitoes-which play an important role in the epidemiology for the affected species- are involved in the transmission of the disease. On the other hand, it has been established that SBV cannot be considered a zoonosis, seeing as so far there is not enough scientific evidence to prove otherwise.

A doença de Schmallenberg (SBV) é uma doença viral emergente produzida por um Orthobunyavirus que foi detectado por primeira vez em bovinos a finais de 2011 em Alemanha. Este afetava de igual forma a ovinos e caprinos, o que gerava particularmente nestas espécies malformações congênitas em fetos de fêmeas prenhas, igualmente que febre e baixa na produção de leite. Hoje em dia, esta doença já se encontra distribuída em vários países de Europa, e se sabe que na transmissão da doença estão implicados vetores culicoides e mosquitos que, para as espécies afetadas, desempenham um papel importante em sua epidemiologia. Por outra parte, foi estabelecido que a SBV não pode ser considerada uma zoonose, já que até o momento não há suficientes evidências científicas que demonstrem o contrário.

Schmallenberg virus (SBV): aprendizajes y lecciones / Schmallenberg virus (SVB): learnings and lessons

En agosto de 2011 se produce en Europa un brote de una enfermedad desconocida en diferentes granjas de ganado vacuno en la localidad de Schmallenberg. Se realiza el alerta epidemiológico, y se comienza a seguir la evolución de la enfermedad. Para el desarrollo del trabajo se hace el seguimiento y análisis de la información producida por la Red PROMED de la International Society for Infectious Diseases. Del seguimiento se obtiene que en el término de 7 meses, 8 países reportan 3323 establecimientos con brotes de esta enfermedad afectando animales de diferentes especies; se diagnostica un nuevo virus que se lo denomina Schmallenberg. Con la definición de esta nueva enfermedad que por el momento no afecta a humanos se producen recomendaciones que hacen al virus, a la transmisión, al control y a la vigilancia epidemiológica.