The ISAKOS subclassification of Rockwood type III AC joint dislocations in a stable type A and an unstable type B is not clinically relevant.

PURPOSE: The treatment of Rockwood type III AC joint dislocations has been debated for decades. In 2014, the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) Upper Extremity Committee suggested a subclassification of the injury into type A, considered stable and best treated nonsurgically, and type B, considered unstable and best treated surgically. Type B is defined by the presence of scapular dyskinesis and overriding of the clavicle to the acromion on a modified lateral radiograph. The objective of the study was to investigate if this subclassification is clinically relevant. METHODS: This was a prospective cohort study. Inclusion criteria were patients aged 18-60 years with acute AC joint dislocation and a baseline Zanca radiograph with an increase in the CC distance of >25% compared to the uninjured side. All patients were treated nonsurgically with 3 months of home-based training and with the option of delayed surgical intervention. Patients were assessed at baseline and at follow-ups 6 weeks, 3 months, 6 months and 1 year after the injury. At the 6-week follow-up, patients were graded as stable and unstable according to the ISAKOS criteria. Outcomes were the Western Ontario Shoulder Instability Index (WOSI) and referral for surgery. RESULTS: At 6 weeks of follow-up, 20 patients were classified as stable type A and 69 were classified as unstable type B. The ISAKOS subclassification was not clinically relevant, but patients graded as stable had statistically significantly better WOSI scores at 6 months compared to the unstable group (p = 0.03) but not at 3 months or 1 year. Nine patients (9.5%), all from the unstable group, were referred for surgery. No patients from the stable group underwent surgery (n.s). CONCLUSION: The ISAKOS subclassification of Rockwood type III in a stable type A and an unstable type B is not clinically applicable. LEVEL OF EVIDENCE: Level II.

Patient-reported, clinical and radiological factors associated with the result after non-surgical management of acute AC joint dislocation Rockwood type III and V.

PURPOSE: The treatment of Rockwood type III and V acromioclavicular (AC) joint dislocations is controversial, and an individualized treatment algorithm is yet to be developed. The objective of this study was to investigate the association of demographical, clinical, patient-reported and radiological variables with the Western Ontario Shoulder Instability Index (WOSI) score and risk of surgery. METHODS: Inclusion criteria for this prospective cohort study were patients aged 18-60 with an acute AC joint dislocation with >25% increase in the coracoclavicular distance on bilateral Zanca radiographs. Patients were treated non-surgically with 3 months of home-based training and the option of delayed surgical intervention. The outcomes were the WOSI score and surgery yes/no. Demographical, clinical, patient-reported (WOSI and Shoulder Pain and Disability Index [SPADI]) and radiological variables were collected at baseline and 6 weeks after the injury and investigated for association with the outcomes at 3 months, 6 months and 1 year. RESULTS: Ninety-five patients with Rockwood type III/V AC joint dislocation were included. Pre-injury participation in overhead/collision sports was a risk factor for surgery with an odds ratio of 5 (p = 0.03). Reduced range of motion (ROM) at baseline was associated with reduced WOSI scores and increased risk of surgery. At 6 weeks, reduced ROM, increased SPADI and increased pain during cross-over were associated with the outcomes. Radiological measurements were not correlated with the result. At the 6 weeks follow-up, patients eventually requiring surgery could be detected with a sensitivity of 100% and a specificity of 94% based on a SPADI score of >30 and a ROM ≤ 140° in shoulder flexion or abduction. CONCLUSION: ROM was the only variable consistently associated with both WOSI and risk of surgery. Six weeks after the injury, it was possible to detect patients in need of surgery based on ROM and SPADI with a sensitivity of 100% and a specificity of 94%. LEVEL OF EVIDENCE: Level II.

Parallel Sequencing Reveals Campylobacter spp. in Commercial Meat Chickens Less than 8 Days Old.

Campylobacter from contaminated poultry meat is a major source of human gastroenteritis worldwide. To date, attempts to control this zoonotic infection with on-farm biosecurity measures have been inconsistent in outcome. A cornerstone of these efforts has been the detection of chicken infection with microbiological culture, where Campylobacter is generally not detectable until birds are at least 21 days old. Using parallel sequence-based bacterial 16S profiling analysis and targeted sequencing of the porA gene, Campylobacter was identified at very low levels in all commercial flocks at less than 8 days old that were tested from the United Kingdom, Switzerland, and France. These young chicks exhibited a much greater diversity of porA types than older birds testing positive for Campylobacter by culture or quantitative PCR (qPCR). This suggests that as the bacteria multiply sufficiently to be detected by culture methods, one or two variants, as indicated by porA type, dominate the infection. The findings that (i) most young chicks carry some Campylobacter and (ii) not all flocks become Campylobacter positive by culture suggest that efforts to control infection, and therefore avoid contamination of poultry meat, should concentrate on how to limit Campylobacter to low levels by the prevention of the overgrowth of single strains. IMPORTANCE Our results demonstrate the presence of Campylobacter DNA among fecal samples from a range of commercially reared meat chicks that are less than 8 days of age, consistent across 3 European countries. The recently developed, sensitive detection method indicates that infection occurs on commercial farms much earlier and more widely than previously thought, which opens up new opportunities to control Campylobacter contamination at the start of the food chain and reduce the unacceptably high levels of human disease.

Airway exposure to multi-walled carbon nanotubes disrupts the female reproductive cycle without affecting pregnancy outcomes in mice.

BACKGROUND: The use of multiwalled carbon nanotubes (MWCNT) is increasing due to a growing use in a variety of products across several industries. Thus, occupational exposure is also of increasing concern, particularly since airway exposure to MWCNTs can induce sustained pulmonary acute phase response and inflammation in experimental animals, which may affect female reproduction. This proof-of-principle study therefore aimed to investigate if lung exposure by intratracheal instillation of the MWCNT NM-400 would affect the estrous cycle and reproductive function in female mice. RESULTS: Estrous cycle regularity was investigated by comparing vaginal smears before and after exposure to 67 µg of NM-400, whereas reproductive function was analyzed by measuring time to delivery of litters after instillation of 2, 18 or 67 µg of NM-400. Compared to normal estrous cycling determined prior to exposure, exposure to MWCNT significantly prolonged the estrous cycle during which exposure took place, but significantly shortened the estrous cycle immediately after the exposed cycle. No consistent effects were seen on time to delivery of litter or other gestational or litter parameters, such as litter size, sex ratio, implantations and implantation loss. CONCLUSION: Lung exposure to MWCNT interfered with estrous cycling. Effects caused by MWCNTs depended on the time of exposure: the estrous stage was particularly sensitive to exposure, as animals exposed during this stage showed a higher incidence of irregular cycling after exposure. Our data indicates that MWCNT exposure may interfere with events leading to ovulation.

Biomechanical and neuromuscular characteristics in patients with traumatic anterior shoulder instability undergoing arthroscopic Bankart repair: a clinical prospective cohort study protocol.

INTRODUCTION: Traumatic shoulder dislocation is a common shoulder injury, especially among the young and active population. More than 95% of dislocations are anterior, in which the humeral head is forced beyond the anterior glenoid rim. The injury leads to increased joint laxity and recurrence rates are high. There is evidence that the shoulder biomechanics and neuromuscular control change following dislocation, but the existing literature is scarce, and it remains to be established if and how these parameters are useful in the clinical setting. The aim of this exploratory prospective cohort study is to investigate biomechanical and neuromuscular outcomes in patients with traumatic anterior shoulder instability undergoing arthroscopic Bankart repair, to test the hypothesis that examinations of these characteristics are applicable in the clinical setting to assess shoulder instability. METHODS AND ANALYSIS: This is a prospective multicentre cohort study with repeated measures of 30 patients undergoing arthroscopic Bankart repair. With carefully selected and completely non-invasive examination methods, we will investigate biomechanical and neuromuscular outcomes in the affected shoulders once presurgically and twice post surgically at 6 and 12 months. Patients' contralateral shoulders are investigated once to establish a preinjury level. ETHICS AND DISSEMINATION: The study was approved by the Capital Region Ethics Committee (journal-no: H-21027799) and the Capital Region Knowledge Center for Data Reviews (journal-no: P-2021-842) before patient recruitment began. The study results will be published in international peer-reviewed journals, online and in other relevant media, presented at medical conventions and disseminated to clinicians and patients as appropriate. TRIAL REGISTRATION NUMBER: NCT05250388.

Control charts for identifying systematic errors using control sera to detect antibody to Salmonella in an indirect ELISA.

This study evaluated the preparation of Shewhart's control charts using the concept of rational subgroups for monitoring the Salmonella antibody ELISA used for surveillance of Danish pig herds. Control charts were prepared for a buffer control sample, a negative serum sample and a positive serum sample. The quality control variables were the natural logarithm (In) of the uncalibrated optical density (OD) for the buffer control sample and the negative serum sample, and the calibrated OD (OD%) for the positive serum sample. Testing round (run) within laboratory robot was chosen as the subgroup, and separate control charts were prepared for five robots. The control limits were set at six times the standard deviation for In(OD) and three times the standard deviation for OD%. Evaluation based on a number of sensitising rules for control charts produced from historical data showed that use of the control charts could reveal systematic analytical errors.

Postweaning multisystemic wasting syndrome in Danish pig herds: productivity, clinical signs and pathology.

A case-control study of 74 herds with postweaning multisystemic wasting syndrome (pmws) and 74 matched control herds was carried out. In the case herds the mortality rates of weaner and finisher pigs were 11.2 and 5.2 per cent respectively, compared with 3.1 and 3.2 per cent in the control herds. In most case herds, pmws developed within the first four weeks after weaning. Wasting, diarrhoea and respiratory signs were observed in 10 per cent of the weaner pigs (7 to 30 kg) in the case herds compared with 7 per cent in the control herds. The average daily gains of the weaner pigs and finisher pigs were 36 g and 52 g less in the case herds than in the control herds. By examining three weaner pigs from each herd the pmws diagnosis was confirmed by histopathology and immunohistochemistry in 78 per cent of the case herds, but at least one pmws-positive weaner pig was found in 19 of the control herds. The prevalence of pmws-positive pigs among illthriven weaner pigs was 45 per cent (101/222) in the case herds, and 12 per cent (27/222) in the control herds. Specific gross pathological findings were associated with a positive pmws diagnosis; pigs with heavy, rubber-like lungs, atonic intestines, and enlarged bronchial and inguinal lymph nodes, had a 0.7 probability of a positive pmws diagnosis by laboratory examinations. However, for illthriven pigs, this probability of having pmws was equal in the case herds and the control herds.

Demonstrating freedom from disease using multiple complex data sources 2: case study--classical swine fever in Denmark.

A method for quantitative evaluation of surveillance for disease freedom has been presented in the accompanying paper (Martin et al., 2007). This paper presents an application of the methods, using as an example surveillance for classical swine fever (CSF) in Denmark in 2005. A scenario tree model is presented for the abattoir-based serology component of the Danish CSF surveillance system, in which blood samples are collected in an ad hoc abattoir sampling process, from adult pigs originating in breeding herds in Denmark. The model incorporates effects of targeting (differential risk of seropositivity) associated with age and location (county), and disease clustering within herds. A surveillance time period of one month was used in the analysis. Records for the year 2005 were analysed, representing 25,332 samples from 3528 herds; all were negative for CSF-specific antibodies. Design prevalences of 0.1-1% of herds and 5% of animals within an infected herd were used. The estimated mean surveillance system component (SSC) sensitivities (probability that the SSC would give a positive outcome given the animals processed and that the country is infected at the design prevalences) per month were 0.18, 0.63 and 0.86, for among-herd design prevalences of 0.001, 0.005 and 0.01. The probabilities that the population was free from CSF at each of these design prevalences, after a year of accumulated negative surveillance data, were 0.91, 1.00 and 1.00. Targeting adults and herds from South Jutland was estimated to give approximately 1.9, 1.6 and 1.4 times the surveillance sensitivity of a proportionally representative sampling program for these three among-herd design prevalences.

Risk factors for Actinobacillus pleuropneumoniae serotype 2 infection in Danish genetic specific pathogen-free pig herds.

Between 1994 and 1998, 297 genetic specific pathogen-free (spf) pig herds participated in a monthly clinical and serological monitoring programme for infection with Actinobacillus pleuropneumoniae serotype 2 (ap-2). The average annual herd-level incidence was 3.4 per cent but there was a significant decreasing trend. A risk index, summing up the exposure from ap-2-infected neighbouring pigs within a 3 km radius, was derived from a geographical information system. A survival analysis indicates that the risk of ap-2 infection increased in proportion to the risk index, suggesting that local spread of ap-2 from infected neighbours was a significant factor. However, herd-specific purchase policies were not apparently associated with the risk of ap-2 infection.

Blocking enzyme-linked immunosorbent assay for detection of antibodies against Actinobacillus pleuropneumoniae serotype 6 in pig serum.

A blocking enzyme-linked immunosorbent assay (ELISA) detecting antibodies against Actinobacillus pleuropneumoniae (Ap) serotype 6 was developed. The blocking ELISA was based on the inhibition of a polyclonal antibody raised against Ap serotype 6. Purified lipopolysaccharide from Ap serotype 6 was used as antigen. The blocking ELISA was tested against sera from pigs experimentally infected with the 12 serotypes of Ap biotype 1. Cross-reaction with serotypes 3 and 8 but not with other serotypes was observed. The sensitivity and specificity of the test on a herd level were evaluated with sera from herds naturally infected with serotypes 2, 6, 8 or 12 and with sera from herds free of infection with any Ap serotype. The blocking ELISA showed a high herd sensitivity (1.00 (0.79-1.00)) and specificity (0.97 (0.93-0.99)).

Evaluation and application of ribotyping for epidemiological studies of Actinobacillus pleuropneumoniae in Denmark.

The aim of the present study was to evaluate ribotyping as an epidemiological tool for Actinobacillus pleuropneumoniae and apply the method in studies of A. pleuropneumoniae infections in Danish pig herds. The evaluation of ribotyping was based on the 13 international reference strains and 106 epidemiologically unrelated Danish field strains representing the nine serotypes of biotype 1 (1, 2, 5A/B, 6, 7, 8, 10, 12, and K2:O7) and one serotype 14 of biotype 2. Enzymes CfoI and HindIII were chosen for generation of ribotype patterns. Ribotyping of the reference strains resulted in 10 CfoI types and 11 HindIII types. Ribotyping of the Danish strains resulted in 17 different CfoI ribotypes and 24 different HindIII ribotypes. Combining HindIII- and CfoI-ribotyping divided the Danish strains into 26 different types. The stability, reproducibility and typability of ribotype patterns were good, and the discriminatory power was between 0.85-0.89. The relatively low discriminatory power was caused by four predominant types, containing 61% of the isolates. The typing system was applied in studies of routes of infection of specific pathogen-free (SPF) pig herds and included 112 strains of A. pleuropneumoniae. Airborne transmission from neighboring conventional pig farms was investigated in 12 cases of infected SPF herds. Transmission via vehicles transporting pigs between SPF herds was investigated in nine cases while transmission by trading of pigs between SPF herds was investigated in two cases. Serotype 2 was isolated from all SPF herds included in this study, except one, emphasizing the high prevalence of this serotype in Denmark. By ribotyping, airborne transmission was indicated in five of 12 cases, transmission via pig transporting vehicle was indicated in six of nine cases, and transmission via trading was indicated in one of two cases. In many cases findings of predominant ribotypes made interpretations of suspected routes of transmission difficult. The relationship of strains based on ribotypes was calculated using Dices coefficient and clustered by UPGMA. HindIII ribotypes of serotype 2 strains were closely related, though only showing 43% similarity to HindIII ribotypes of remaining serotypes.

Mycoplasma hyopneumoniae infection in pigs: duration of the disease and evaluation of four diagnostic assays.

200 SPF pigs were infected by aerosol with Mycoplasma hyopneumoniae and the development of clinical signs, serological and pathological reactions were studied. Mean time to onset of coughing was 13 days. A mean delay of 9 days was observed from onset of coughing until seroconversion against M. hyopneumoniae as measured by ELISA. At an individual level, the sensitivity for this ELISA was estimated to 98-100% and the specificity to 93-100%. Pasteurella multocida was isolated from the majority of the lungs 4 weeks post inoculation with M. hyopneumoniae and the lung lesions in pigs were significantly larger when P. multocida was present as compared to pigs with M. hyopneumoniae alone. An evaluation of cultivation, immunofluorescence, ELISA and polymerase chain reaction for demonstration of M. hyopneumoniae in lungs showed that all four methods have a high sensitivity in the acute stages of pneumonia. In the later stages the sensitivity of cultivation was superior to the other methods. No differences in specificity were observed between the methods. The antigen-ELISA OD values and the immunofluorescence scores revealed a strong positive correlation. Nasal swabs were additionally used for demonstration of M. hyopneumoniae and the polymerase chain reaction was found superior to the other methods.

Application of enzyme-linked immunosorbent assay for the surveillance of Mycoplasma hyopneumoniae infection in pigs.

A monoclonal antibody-based blocking enzyme-linked immunosorbent assay (ELISA) was used for serological surveillance of Mycoplasma hyopneumoniae infection in pig herds. A follow-up study was conducted on "herd predictive values" previously reported for this ELISA. Of those herds giving positive results by this ELISA, 42% were subsequently found to be infected, while 100% of herds giving negative results were uninfected. Previous reports recorded positive and negative herd predictive values of 39% and 99.8%, respectively. Among naturally-infected animals, reaction in colostrum was more frequent than in serum, and this difference was most pronounced if the colostrum samples were obtained shortly before or after farrowing. Coughing was found to be the most reliable clinical indicator of infection, but surveillance through clinical herd inspections alone failed to detect 30% of infected herds. The time required for seroconversion following natural exposure to M. hyopneumoniae differed in two herds using different management systems: in one herd antibodies were first detected three weeks post-exposure, while in the other herd antibodies were not detected until five weeks after exposure.

Designing serological surveillance programmes to document freedom from disease with special reference to exotic viral diseases of pigs in Denmark.

Surveillance programmes based on laboratory screening tests are increasingly used to document freedom from disease in order to facilitate trade. The following aspects must be considered when designing such programmes: diseases to be selected; epidemiology of the diseases; unit of analysis (animal or herd); target age group (or target farm type); test characteristics and sample size. Issues related to these aspects are discussed and illustrated using the example of serological surveillance for exotic viral diseases in the pig population of Denmark. Sampling designs based on individual animal samples are compared with herd-based sampling (two-stage sampling). While the latter is likely to require a larger sample size, the increased level of information and the reliability of the results obtained are considered to be worth the expense. Issues related to the development of international standards for declaring freedom from disease are discussed. The authors conclude that international standards are desirable, providing that these standards represent scientifically valid principles.

Vaccination against progressive atrophic rhinitis with a recombinant Pasteurella multocida toxin derivative.

Vaccination against progressive atrophic rhinitis using a purified recombinant derivative of the Pasteurella multocida toxin (PMT), was carried out. Ten pregnant gilts were vaccinated twice with the nontoxic derivative (dO) which apart from a lack of 121 amino acids had an amino acid sequence identical to PMT, while seven gilts were vaccinated with a purified, formaldehyde treated, native PMT and ten gilts served as non-vaccinated controls. The resulting piglets were inoculated intranasally with Bordetella bronchiseptica and toxigenic P. multocida. Among piglets from the nonvaccinated gilts all except one developed clinical atrophic rhinitis and 90% developed severe turbinate atrophy while only a few pigs in the vaccinated groups developed clinical or pathological signs of disease. Gilt colostra from the two vaccinated groups had similar mean anti-PMT titers and the mean titers in the offspring's sera from these groups were nearly identical throughout the study. No pigs born from unvaccinated gilts were seropositive until 8 wk of age (7 wk post-challenge) but 23% became seropositive at slaughter. The infection rate with toxigenic P. multocida in piglets and the total number of P. multocida colonies cultured from nasal swabs were significantly reduced at 5 wk and 8 wk of age in the vaccinated groups, when compared to controls. There was a significantly improved weight gain (greater than 9%) from birth to slaughter in offspring from vaccinated gilts. No significant differences in feed conversion rate or % lean meat were observed among the groups. The study showed the excellent immunoprotective properties of the nontoxic derivative of the PMT molecule.

Evaluation of a monoclonal blocking ELISA and IHA for antibodies to Mycoplasma hyopneumoniae in SPF-pig herds.

A monoclonal blocking enzyme-linked immunosorbent assay (ELISA) and an indirect haemagglutination assay (IHA) were applied to serum samples from 124 specific pathogen-free (SPF) breeding and multiplying herds, which participate in the routine serological surveillance of the Danish SPF programme. Clinical and pathological observations of the herds and microbiological culturing of Mycoplasma hyopneumoniae were used to calculate herd sensitivity, herd specificity and herd predictive values for the two serological assays. The ELISA was superior to the IHA in herd sensitivity and herd specificity, with values of 93 per cent and 96 per cent, respectively, for the ELISA, and 61 per cent and 92 per cent for the IHA. During the six month period of evaluation 2.5 per cent of the herds were infected with M hyopneumoniae each month. At this level the IHA was found to have a positive herd predictive value of 16 per cent, compared with 39 per cent for the ELISA. The negative herd-predictive value on the same level was 99.8 per cent for the ELISA and 98.9 per cent for the IHA. If the assays were applied to a group of herds with a herd prevalence of M hyopneumoniae infection of 30 per cent (as is the case with the production herds in the Danish SPF programme) the predictive value of a positive herd diagnosis would be 91 per cent for the ELISA and 76 per cent for the IHA, and the predictive value of a negative herd diagnosis would be 97 per cent with the ELISA and 85 per cent with the IHA.(ABSTRACT TRUNCATED AT 250 WORDS)

Description of extended pre-harvest pig Salmonella surveillance-and-control programme and its estimated effect on food safety related to pork.

Salmonella in pork can be combated during pre- or post-harvest. For large slaughterhouses, post-harvest measures like decontamination might be cost-effective while this is less likely with small-to-medium sized slaughterhouses. In this study, pre-harvest measures might be more relevant. We describe an extended surveillance-and-control programme for Salmonella in finisher pigs, which, to establish equivalence to the Swedish control programme, is intended for implementation on the Danish island, Bornholm. The effect of the programme on food safety was estimated by analysing Salmonella data from pig carcasses originating from herds that would have qualified for the programme during 2006-2008. Food safety was interpreted as prevalence of Salmonella on carcasses as well as the estimated number of human cases of salmonellosis related to pork produced within the programme. Data from the Danish Salmonella programme were obtained from Bornholm. We used a simulation model developed to estimate the number of human cases based on the prevalence of Salmonella on carcass swabs. Herds are only accepted in the programme if they have one or less seropositive sample within the previous 6 months. In this way, the Salmonella load is kept to a minimum. The programme is not yet in operation and pigs that qualify for the programme are currently mixed at slaughter with those that do not qualify. Therefore, we had to assess the impact on the carcass prevalence indirectly. The prevalence of Salmonella in carcass swabs among qualifying herds was 0.46% for the 3 years as a whole, with 2006 as the year with highest prevalence. According to the simulation the expected number of human cases relating to pork produced within the programme was below 10. When the programme is in operation, an extra effect of separating pigs within the programme from those outside is expected to lower the prevalence of Salmonella even further.

Effect of vaccination of sows with Bordetella bronchiseptica on the incidence of atrophic rhinitis in swine.

Vaccination of pregnant sows with Bordetella bronchiseptica was performed in an SPF herd with clinical atrophic rhinitis. Agglutinins against the organism were induced in serum and colostrum by the vaccination. The antibody titres were generally higher in colostrum than in corresponding serum samples. The frequency at slaughter of turbinate atrophy (+, ++, +++) was lower among pigs from vaccinated sows (11%) than in pigs borne by unvaccinated sows (20%). In the control group a lower daily weight gain was observed in pigs with turbinate atrophy than in pigs with normal noses. The mean daily weight gain in pigs with turbinate atrophy borne by vaccinated sows was slightly lower than in pigs without atrophy of conchae, but the difference was not significant. A specific immunological prophylaxis might be an alternative to antibacterial treatment in herds where atrophic rhinitis is aetiologically related to B. bronchiseptica infection.

Influence of vaccination of sows with Bordetella-Pasteurella vaccines on the occurrence of atrophic rhinitis among their offspring after experimental infection with Bordetella bronchiseptica and toxigenic Pasteurella multocida.

Experimental infections with Bordetella bronchiseptica and a toxigenic strain of Pasteurella multocida were carried out in newborn piglets from 25 sows. Severe progressive atrophic rhinitis corresponding to the natural disease was produced. The effect of vaccination of sows during pregnancy with two vaccines containing antigens from B. bronchiseptica and toxigenic P. multocida on the incidence of nasal lesions in the offspring was studied.

Effect on the incidence of atrophic rhinitis of vaccination of sows with a vaccine containing Pasteurella multocida toxin.

Combined experimental infections with Bordetella bronchiseptica and either a toxigenic or a non-toxic strain of P. multocida were carried out in newborn specific pathogen free piglets born to 25 sows. Pigs inoculated with B. bronchiseptica and toxin-producing P. multocida developed severe progressive atrophic rhinitis corresponding to the natural disease. The effect of vaccination of sows with a toxin-containing P. multocida vaccine on the incidence of nasal lesions in the offspring was studied.