Vaccination of influenza a virus decreases transmission rates in pigs

Romagosa, Anna; Allerson, Matt; Gramer, Marie; Joo, Han Soo; Deen, John; Detmer, Susan; Torremorell, Montserrat

Transmission experiments and mathematical models have been used to quantify vaccine-induced reduction in the spread of Mycoplasma hyopneumoniae, pseudorabies virus, classical swine fever, Actinobacillus pleuropneumoniae, encephalomyocarditis virus (EMCV), foot and mouth disease (FMDV), porcine reproductive and respiratory syndrome virus (PRRSV), hepatitis E virus, and porcine circovirus type 2 (PCV-2) in pigs [15] [16] [17] [18] [19] [20] [21] [22] [23] . In order to quantify transmission of a pathogen, a key parameter is the reproduction ratio (R) of the infection which is defined as the average number of secondary cases caused by an infectious individual in a population during its entire infectious period [24, 25] . When R is greater than 1, an infection can spread in a population but if R is less than 1, the infection will die out within a population. The estimation of R can provide important information about the potential for transmission of infection, the dynamics of infection at the population level, and the impact of disease control strategies [15, 26, 27] .