Original article from: The New York Times posted on September 26, 2014.
Paul Duprex, PhD
Director of Cell and Tissue Imaging Core; Professor of Microbiology
BSc, The Institute for Animal Health, Pirbright and The Queen’s University of Belfast, United Kingdom
PhD, The Queen’s University of Belfast, United Kingdom
Viral pathogenesis and attenuation are two sides of the one coin and paramyxoviruses represent an important family of respiratory pathogens which permit us to study the molecular basis of each. Some paramyxoviruses infect only a single species whereas others have a wide host range and have a significant zoonotic potential making them attractive viruses to examine the barriers to cross-species infection.
Measles virus is the prototypic morbillivirus which, in spite of huge progress in recent years, causes a vaccine-preventable disease leading to the death of many children in the developing world every year. The virus is incredibly infectious and over 95% of a population must be vaccinated to halt transmission. Although no longer endemic in large swaths of the developed world, importations lead to localized spread in unvaccinated individuals.
The virus is highly lymphotropic, although it can infect neurons, endothelial and epithelial cells in vitro and in vivo. Mumps virus (MuV) is a closely related rubulavirus which is highly neurotropic. Although it has been over 75 years since MuV was identified as the etiological agent of the disease, virtually nothing is known about the molecular basis of virus neurotropism and neurovirulence and molecular markers of attenuation have not been identified.
A number of insufficiently attenuated vaccine strains have caused aseptic meningitis and other serious adverse events in recipients which has led to withdrawal of mumps vaccines, public resistance to vaccination, and, in some countries, complete cessation of national vaccination programs for MuV. Although nearly eliminated from most developed countries by the turn of the century, MuV has recently reemerged as an important public health issue with outbreaks occurring in highly vaccinated populations in the United States and the United Kingdom. MV and MuV are restricted to humans whereas canine distemper virus (CDV) infects a wide range of species, from dogs to lions.