Respiratory Diseases in Pigs

Respiratory diseases cause significant issues in pigs worldwide. Welfare concerns, disease burden, decreased production, and low worker morale can all be effects of swine respiratory diseases. Various infectious and noninfectious agents, alone or in combination, can induce or predispose to respiratory disease in pigs. Viruses and bacteria are the main types of infectious agents affecting the respiratory tract of pigs. Infections of polymicrobial origin are usually termed porcine respiratory disease complex and group disease manifestations of multiviral, multibacterial, or mixed nature. In this chapter, the main diseases affecting the respiratory tract of pigs are briefly described, making emphasis on the basics of etiology, epidemiology, clinical presentation, lesions, treatment, and control for each agent. Viruses such as porcine circovirus type 2, porcine reproductive and respiratory syndrome virus, and influenza A virus and bacteria, namely, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Pasteurella multocida, and Bordetella bronchiseptica, are depicted given their importance in swine health. Other infectious agents and factors potentially affecting the respiratory system of pigs are listed, and readers are encouraged to dig deeper into the understanding of the processes that drive the lack of health of this important body system.