TMEM154 and infection: To provide adequate power in the association of TMEM154 E35K polymorphism with the susceptibility for MV infection, it is necessary to evaluate flocks characterized by a “moderate” level of infection (e.g., not all or most sheep should be positive or negative) and a balanced ratio of sheep carrying the genotypes susceptible (EE/EK) and resistant (KK), but such ideal conditions are challenging to find in the field.