“Serotherapy” had been utilized extensively before commercial vaccines became available in Europe by some European practitioners to control and prevent PMWS; however, the literature reports of this technique are limited to abstracts describing uncontrolled field studies. In those trials, serum was typically obtained from healthy pigs in a group of pigs on the farm that went through PMWS 2-3 months prior. Recipient pigs were then treated by subcutaneous (Ferreira et al., 2001) or intraperitoneal (Waddilove and Marco, 2002) injection of convalescent serum. With both protocols, a significant reduction of clinical disease and mortality was observed. Sick animals treated with serum had a significantly increased survival rate in Spain (48%) and in England (58%) compared with normal survival of below 10% on both farms (Waddilove and Marco, 2002). The overall herd mortality rate of growing pigs in three trials was reduced from 15-18% in untreated pigs to 2-5% in treated pigs (Ferreira et al., 2001).
A controlled study tested efficacy of serotherapy at minimizing PCV2-associated disease and lesions (Halbur et al., 2005). Serum from experimentally-infected pigs in the acute and convalescent stages of infection was used. In addition, serum from pigs with high levels of anti-PCV2 maternal antibodies was also used. These three serotherapy treatments were compared to a group that was vaccinated with an experimental PCV1-2 chimeric vaccine. All pigs were necropsied at 21 DPI. The group vaccinated with the chimeric vaccine had significantly (P < 0.05) lower levels of viremia than all other groups and four of the seven pigs in this group remained PCV2 negative by PCR for the duration of the project. Under the conditions of this study, neither the acute- or convalescent-serotherapy were effective practices for preventing PCV2 infection and PCV2-associated lesions. The apparent success of serotherapy reported in European field trials remains unexplained. The experimental PCV1-2 chimeric vaccine appears to be effective, safe, and superior to serotherapy in reducing PCV2 infection and viremia (Halbur et al., 2005).
Ferreira D, Sansot B, Laval A: Attempt to use serotherapy to control mortality in PMWS. In: Proc Conf ssDNA Viruses, St. Malo, France. p. 144, 2001
Halbur PG, Opriessnig T, Thomas P: Best practices for control of PCV2-associated diseases. In: Proc Swine Disease Conf Swine Pract, Ames, Iowa. 13:98-107, 2005
Waddilove AEJ, Marco E: Assessing serotherapeutic control of PMWS in the field. In: Proc Intern Pig Vet Soc Conf, Ames, Iowa, 17:204, 2002