Induction of Arthritis with Mycoplasma hyosynoviae in Pigs: Clinical Response and Re‐isolation of the Organism from Body Fluids and Organs

Abstract

The objective of this investigation was to study the pathogenesis of experimental Mycoplasma hyosynoviae arthritis in pigs. The experimental inoculations were designed to provide information about systemic spread, the persistence of subclinical infection, and the length of time for which the mycoplasma is cultivable from synovial fluids and other tissues. In this article we report on the clinical response to infection and the results obtained from re-isolation attempts.In three inoculation experiments with M. hyosynoviae, clinical arthritis was produced by intravenous and by intranasal exposure as well as by pen-contact in 12 out of 23 exposed pigs. The infection was transmitted from persistent carrier pigs to non-infected pigs by pen-contact. The incubation period until development of clinical arthritis was 4-9 days for all routes of exposure, and the symptoms were of variable severity. In half of the cases the onset was acute and the lameness severe, typically involving the hindlegs and with affected pigs assuming a dog-sitting position. A systemic phase was found in the majority (86 %) of the pigs. However, the infection was in two cases established in the tonsils without detection of a systemic phase. An apparent persistent infection of the tonsils became established in all the pigs.M. hyosynoviae spreads via the blood to different organs from which it could be re-isolated during the acute phase of the infection. In general, M. hyosynoviae was recovered from joints from day 3 until day 21 post-exposure, but longer persistence of viable mycoplasmas in joints or regional lymph nodes in the chronic phases of the infection appeared to have taken place in a few pigs. U.S. Copyright Clearance Center Code Statement: 0931-184X/99/4606-0317 $14.00/0 318 HAGEDORN-OLSEN et al. The aim of this study was to investigate the pathogenesis of M. hyosynoviae arthritis. It was the objective to produce arthritis by intravenous (iv.) and intranasal (in.) inoculation, and by pen-contact exposure to pigs in the acute phase of the infection or by pen-contact exposure to chronic carrier pigs. The experiments were designed to provide information about: (i) the incubation time and the clinical course of the infection; (ii) the systemic spread of the mycoplasma, and (iii) the isolation rates of M. hyosynoviae from joints and tonsils during the assumed acute, subacute and chronic phases of the infection. Materials and MethodsPigs and inoculation material Naturally farrowed crossbred (Yorkshire-Landrace) pigs, originating from six litters from two weanerproduction herds known to be infected with Mycoplasma hyopneumoniae, were used. The pigs were moved directly from the sow at 25-28 days of age to an experimental isolation unit at the Royal Veterinary and Agricultural University, Copenhagen, where there was no contact with other pigs. The pigs were proved free from M. hyosynoviae by 2-4 consecutive cultivations of tonsillar scrapings before they were used for the experiments. The pigs were free from any clinical signs of illness and wer...

Comparison of detection procedures of Mycoplasma hyopneumoniae, Mycoplasma hyosynoviae, and Mycoplasma hyorhinis in lungs, tonsils, and synovial fluid of slaughtered pigs and their distributions in Thailand

“…However, the number of M. hyosynoviae persistent in tonsil did not reflect the infective level in herds that was regardless of the occurrence of joint lesions or arthritis (Nielsen et al 2005). This might be explained by the fact that the pathogen might disappear about 3 weeks post-infection or during chronic stage of arthritis at slaughter (Hagedorn-Olsen et al 1999). Additionally, other prevalent pathogens (Erysipelothrix rhusiopathiae, Streptococcus suis, Actinomyces pyogenes, M. hyorhinis, staphylococci, and Streptococcus spp.)…”

Antibody responses of swine following infection with Mycoplasma hyopneumoniae, M. hyorhinis, M. hyosynoviae and M. flocculare

“…The M. hyosynoviae challenge was performed intravenously (IV) as previously described (Hagedorn-Olsen et al, 1999). Four 14-week-old female CDCD pigs were placed in each of the two challenge groups (Table 1).…”

“…All samples were stored at À20 8C until assayed by PCR. (Strasser et al, 1992); M. hyorhinis (Kobisch, 1983); M. hyosynoviae (Hagedorn-Olsen et al, 1999). c IV and IN-intravenous and intranasal challenge.…”

Two clinical isolates ofMycoplasma hyosynoviaeshowed differing pattern of lameness and pathogen detection in experimentally challenged pigs

“…Upon colonization, M. hyosynoviae can persist in the tonsils and animals may become life-long carriers [217]. Bacteremia occurs in a subset of susceptible pigs, and has been shown to precede clinical disease [7]. Although the disease risk factors are not fully understood, M. hyosynoviae -associated arthritis is often reported to occur upon exposure to environmental stressors such as temperature fluctuation, increased stocking density, and commingling of non-litter mates [15].…”

“…However, the virulence determinants and host pathways that converge to the occurrence of the disease phenotype typically seen in field cases are still not understood [111]. Although M. hyosynoviae -associated disease has been experimentally reproduced before [71218], this study was conducted to determine if distinct clinical isolates could have different disease phenotypes, and which inoculation route and infectious dose combination would be more robust to reproduce them. Additionally, multiple diagnostic specimens were tested for the presence of M. hyosynoviae and induced histological alterations to determine the optimal criteria for clinical diagnosis.…”