Actinobacillus pleuropneumoniaein Thai Pig Herds. Prevalence of Serum Antibodies and Relation to Performance

Abstract

The aim of the study was to investigate the prevalence of Actinobacillus pleuropneumoniae infections in market weight pigs in Thailand. ELISA systems employing purified lipopolysaccharide antigens were used to detect antibodies in 549 serum samples collected from pigs of 22 herds. Relevant cut-off values were established from three herds defined seronegative. Serum antibodies were detected to all serotypes except serotype 10. Almost 60% of the samples were seropositive to at least one serotype and 45% of the pigs were seropositive to more than one serotype. Antibodies to the cross-reacting serotypes 1, 9 or 11 were found in 29% of the pigs. Other common serotypes included the cross-reacting serotypes 3, 6 or 8 (26% seropositive pigs) and serotype 5a (also 26%). Antibodies to serotypes 2, 5b and 12 were low in prevalence (<10%). Three herds were regarded to be seronegative and six to have a low pathogen load with respect to the prevalence of seropositive pigs. The remaining 13 herds had a high incidence of pigs with antibodies to A. pleuropneumoniae, dominated by serotypes 1-9-11 and 5a (n = 6), serotypes 3-6-8, and 5a (n = 4) or 1-9-11, 3-6-8, 5a and 4-7 (n = 3). A low pathogen load with respect to A. pleuropneumoniae, as well as small herd size and age-segregated rearing, tended to improve the performance of growers.

Risk Factors for Mortality in Grow‐finishing Pigs in Belgium

“…The mortality percentage was significantly higher in case of a longer duration of the fattening period. It is possible that the pathogen load, impairing the growth of the pigs, was higher in groups that needed more time to reach slaughter weight (Harris and Alexander, 1999; Assavacheep et al., 2003). In addition, it may also be due to the fact that the pigs are for a longer period at risk to die in case of a longer fattening period.…”

Infección por Actinobacillus pleuropneumoniae en un modelo murino = Actinobacillus pleuropneumoniae infection in a murine model

“…La pleuroneumonía porcina es una de las enfermedades respiratorias más importantes en la industria porcina (Williams et al, 2000, Huerta et al, 2004, presentando un cuadro agudo en cerdos, que suelen morir debido a una neumonía hemorrágica necrótica; sin embargo, el impacto económico de la enfermedad se centra más en la disminución de la tasa de crecimiento de los cerdos enfermos crónicos. Enfermedad la cual ha sido estimada en ratones logrando hasta un 33,6% (Taylor 2002;Assavacheep et al, 2003).…”

“…Los determinantes antigénicos del LPS de esta bacteria son también específicos de serotipo, aunque existen suficientes similitudes entre los epítopos como para provocar la existencia de reacciones cruzadas dentro de la especie e incluso con otras (Fenwick y Osburn, 1986; Rodríguez Barbosa et al, 1995). 7 La actividad biológica de la endotoxina de A. pleuropneumoniae es similar a la de otras bacterias Gram negativas. El LPS purificado es capaz de inducir una reacción dérmica de tipo Schwartzman y una respuesta blastogénica de linfocitos sanguíneos periféricos; además, coagula el lisado de amebocitos del cangrejo Limulus polyphemus, es pirogénico y letal para los embriones de pollo (Fenwick y Osburn, 1986;) y activa la vía alternativa del complemento (Inzana, 1991).…”