In spite of the introduction of a highly effective vaccine, yellow fever virus still causes recurrent and deadly burst in Africa. The vaccine strain 17D has been attenuated via several passages of the virulent Asibi strain in chicken embryo tissues, in order to reduce its viscero- and neuro-tropism. The safe vaccine strain YF17D is routinely used to study the biology of yellow fever virus and to understand the immunologic properties of one of the best vaccines ever developed.

Zika virus infection is mostly asymptomatic, or can result in a mild illness. However, the recent explosive spread of Zika in the Americas has caused alarm due to the now established link between Zika infection and microcephaly (reduced head size and brain damage) in new-born babies. Although major efforts are being directed towards a Zika vaccine, experimental evidence of antibody cross-reactivity with dengue virus raises concerns over the possibility of antibody-dependent enhancement and disease aggravation. Many unique aspects of Zika virus infection remain elusive, including the link between viral infection and pathogenesis, and what caused such a rapid diffusion of the Asian strains.

Zika virus African strain (MP1751)
Zika virus Asian strain (H/FP/2013)

Thought to be diffused across several European countries, frequent outbreaks of Sindbis virus infections have been reported in Finland and Sweden. Diseases can be mild or asymptomatic, but in a considerable number of cases SINV infection leads to persistent joint manifestations that can continue for months or years or even become chronic.

Besides being a human pathogen, Sindbis virus is also studied as a model alphavirus and to understand the molecular and immune bases of virus-induced arthritogenic diseases.

Semliki Forest virus rarely causes disease in humans. However, it has been widely adopted as a research tool because of its efficient replication and broad host range. Simliki has been used in the development of gene therapy and as a vector for vaccines and anti-cancer agents. Its neurotropism makes it also a vector of choice for gene delivery to neurons.

Besides of its annual come back, influenza virus is feared to be a likely cause of the next viral pandemic. Scientist around the world are constantly monitoring for new viral strains in the human and animal population, and looking for more permanent solutions to this recurrent threat, like a universal flu vaccine. To support their efforts, we have access to both historical and seasonal influenza A (IAV) and B (IBV) strains, including IAV H1N1 A/WSN/1933 and IBV Yamagata B/Phuket/3073/2013 .

Although generally harmless in adults, RSV remains the main cause of viral-induced pneumonia in infants. While widely studied, there are currently no vaccines or antivirals licensed for RSV.

RSV A2 strain

In late 2019, the emergence of a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), caused an outbreak of viral pneumonia (COVID-19) in Wuhan, China. The entire world is experiencing an unprecedented lockdown, and it is very likely that this virus is going to permanently impact our lifestyle and our perception of infectious diseases.

Vaccinia virus is the poxvirus that was used to eradicate Variola virus, or smallpox, a much more aggressive and highly lethal member of the same family. Vaccinia is a large DNA virus that is still used to date as a model poxvirus, and as a vector to design safer and more immunogenic vaccines. Also, its complex network of interaction with cellular proteins makes of vaccinia and invaluable tool to discover new cellular functions and defense mechanisms.

Vaccinia virus Western Reserve

HCMV represents a health risk mostly for immune compromised individual and for transplant patients, however, its widespread presence and the lack of vaccines and well-tolerated therapies make it a priority for antiviral development. At VRS we work with the Merlin strain, which although adapted to grow in tissue culture conditions, still remains one of the most genetically close to clinical isolates.

HCMV Merlin strain