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We assessed the bacterial agents found in 8–12-wk-old post-weaning pigs with arthritis. The bodies of 178 post-weaning pigs from 90 farms (average of 2 pigs/farm) with recurrent problems of lameness and swollen joints in a high-density breeding area were submitted for autopsy and sampled for further bacterial investigation. The most common articular gross lesions and histopathologic findings were serofibrinous (95 of 178; 53%) or serous (65 of 178; 37%) arthritis; suppurative lesions were less frequent (18 of 178; 10%). In 133 of 178 (74.7%) cases, a bacterial agent was detected in joints. Mycoplasma hyorhinis was the most common bacterium detected (82 of 133; 61.6%). Haemophilus parasuis and Streptococcus spp. were observed in 27 of 133 (20.3%) and 24 of 133 (18.0%) cases, respectively. Other bacteria in the 113 cases, considered less important, in order of their low frequency, were Mycoplasma spp. (13; 9.8%), Trueperella pyogenes (11; 8.2%), Mycoplasma hyosynoviae (4; 3.0%), Staphylococcus spp. (3; 2.2%), Escherichia coli (2; 1.5%), and Actinobacillus spp. (2; 1.5%). Our results highlight the primary role of M. hyorhinis compared to other microorganisms involved in young pigs with arthritis. [ABSTRACT FROM AUTHOR]

Haemophilus parasuis is an economically important swine pathogen with 15 recognized serovars. An enzyme-linked immunosorbent assay (ELISA) was developed that detects serum antibodies to the oligopeptide permease A (OppA) polypeptide membrane protein present in the reference strains for 13 of the H. parasuis serovars. Using the OppA-ELISA, H. parasuis serologic profiles were assessed on 2 swine farms, with seroconversion defined as an OppA-ELISA sample-to-positive (S/P) ratio ≥0.5. Ten gilts from each farm were vaccinated for H. parasuis using either a live avirulent culture vaccine (farm 1) or an inactivated autogenous vaccine (farm 2). Seroconversion occurred in 100% of farm 1 gilts and 90% of farm 2 gilts, with a mean S/P ratio (MSPR) of 3.36 and 1.43, respectively. The OppA-ELISA MSPRs were determined for 2 piglets, 1 male and 1 female, randomly selected from 10 first-parity (P1), 10 second-parity (P2), and 10 third-parity (P3) litters farrowed by respective vaccinated gilts on each farm. On both farms, postfarrowing MSPRs and rate of seropositivity were highest in P1 versus P2 and P3 dams. Parity 1 piglets had higher MSPRs and rates of seropositivity versus later parities, with the difference being significant (P < 0.05) on farm 2. Polymerase chain reaction analysis of nasal swabs indicated that 100% of farm 1 piglets and 47–84%, depending on parity, of farm 2 piglets were H. parasuis–colonized at weaning. The results indicated that H. parasuis vaccination of gilts will not maintain serologic responses in the OppA-ELISA over their reproductive lifetimes, and that maternally derived antibodies do not prevent H. parasuis colonization of piglets. [ABSTRACT FROM AUTHOR]

Haemophilus parasuis is a recognized pathogen in domestic pigs; the pathogen has been also isolated from healthy wild boar (Sus scrofa). In the current report, a case of fatal H. parasuis infection in a wild boar piglet from central Spain is described. The affected animal presented severe pneumonic lesions, inflammation in tarsal joints with presence of fibrinous deposits, and epidural hemorrhage in the atlanto-occipital joint. Pure growth of H. parasuis was obtained from lungs and tarsal joints. The current case illustrates the susceptibility of wild boar to this agent. The gross pathology results were similar to that described in domestic pigs, but there were no fibrinous deposits on serosal surfaces. [ABSTRACT FROM PUBLISHER]

The article presents a study that investigates the efficacy of polymerase chain reaction amplification of the 16S ribosomal (r)RNA and the putative hemolysin gene operon, hhdBA, in detecting pigs with Glässer disease in Australia. Researchers examined and studied 140 pigs that are positive of Haemophilus parasuis by taking swab samples from their tonsil, lungs, nasal cavity and trachea. Moreover, they found that 30 pigs are positive of the disease.

The article describes the development of a nested polymerase chain reaction (nPCR) assay to determine the presence of a gene encoding a bacteriophage Mu-like portal protein, gp29, in 15 reference strains and 31 field isolates of Haemophilus parasuis. It cites the utilization of specific primers and notes that most of the virulent reference strains and field isolates tested harbored the gene. The results suggest the nPCR technique's potential as a tool for epidemiological studies of H. parasuis.

The article presents a study which cultured nasal swabs from pigs preweaned and sick weaned pigs on a farm in Queensland for the presence of Haemophilus (H.) parasuis. Findings revealed that most of the isolates of genotype 1 did not amplify in the species-specific conventional polymerase chain reaction (PCR) number 1 (cPCR1) based on the 16s ribosomal ribonucleic acid (rRNA) gene. The researchers also found false-negative reactions in the recognized PCR tests for H. parasuis.