Survival of Actinobacillus pleuropneumoniae outside the pig.

Transmission of Actinobacillus pleuropneumoniae is primarily thought to be via direct transfer of mucus from pig to pig. For transfer between farms, the organism may need to persist in the wet or dried state to be carried on an inanimate surface. The survival of A. pleuropneumoniae was investigated under controlled laboratory conditions. In aqueous suspension, survival was improved by the presence of NaCl and mucin; it was prolonged at lower temperature. In dry state, it survived best on a hydrophobic surface either under desiccated conditions or saturated humidity. Detectable viability was maintained for 3-4 days. When frozen, A. pleuropneumoniae survived for more than 17 weeks at -20 °C, but the viability declined to 0.01% during that time. Survival at -70 °C was effective for long term storage. Results obtained from this investigation would be applicable for sampling method, transport techniques, epidemiological study, and biosecurity implementation.

One world--one health: the threat of emerging swine diseases. An Asian perspective.

Owing to the expanding globalization, the trans-boundary spread of an epizootic can easily result from uncontrolled animal movements and human traffic. Foot and mouth disease (FMD) is a major trans-boundary disease in most Asian countries. Its sporadic re-emergence suggests that collaborative FMD control strategies should be uniformly implemented in endemic countries to ensure the overall national herd vaccination coverage, biocontainment when outbreaks occur, and strict biosecurity control of animal movement between countries. Sustained commitments from governments, cooperative diplomatic relationships, and public awareness campaigns are critical to FMD control, to ensure collaboration among veterinarians, traders and farmers throughout Southeast Asia (SEA). Recently, highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) and porcine epidemic diarrhoea (PED) spread from China to Southeast Asian countries, causing major economic losses. Foot and mouth disease, HP-PRRS, and PED currently remain endemic and may continue to sporadically re-emerge, owing to inadequate public health management and/or biosecurity failures. Therefore, the risk factors must be identified to better understand the epidemiology of these diseases in an effort to develop effective control measures. International coordination through the establishment of a collaborative network supported by the World Organization for Animal Health (OIE) and the Food and Agriculture Organization (FAO) should be implemented to prevent trans-boundary transmission among countries. This review discusses trans-boundary swine diseases of particular importance to SEA, including FMD, HP-PRRS and PED, with a primary focus on major factors contributing to the spread of these diseases and important control measures, reflecting the impact of globalization on disease control and surveillance.

Actinobacillus pleuropneumoniae in Thai pig herds. Prevalence of serum antibodies and relation to performance.

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.