The pathogenesis of Type 2 highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) in 10-week old swine in the United States was investigated. rJXwn06, rescued from an infectious clone of Chinese HP-PRRSV, replicated in swine with at least 100-fold increased kinetics over U.S. strain VR-2332. rJXwn06 caused significant weight loss, exacerbated disease due to bacterial sepsis and more severe histopathological lung lesions in pigs exposed to HP-PRRSV than to those infected with VR-2332. Novel findings include identification of bacterial species present, the degree of thymic atrophy seen, and the inclusion of contact animals that highlighted the ability of HP-PRRSV to rapidly transmit between animals. Furthermore, comprehensive detailed cytokine analysis of serum, bronchoalveolar lavage fluid, and tracheobronchial lymph node tissue homogenate revealed a striking elevation in levels of cytokines associated with both innate and adaptive immunity in HP-PRRSV infected swine, and showed that contact swine differed in the degree of cytokine response. © 2012.
Guo, B., Lager, K. M., Henningson, J. N., Miller, L. C., Schlink, S. N., Kappes, M. A., … Faaberg, K. S. (2013). Experimental infection of United States swine with a Chinese highly pathogenic strain of porcine reproductive and respiratory syndrome virus. Virology, 435(2), 372–384. https://doi.org/10.1016/j.virol.2012.09.013