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BackgroundInfluenza A virus in swine (IAV‐S) causes an acute respiratory disease of swine which results in great economic losses in pig production. Major control strategies include the use of killed vaccines (KV) in breeding females to confer passive immunity to their offspring. A bivalent H1N1 and H3N2 NS1‐truncated live attenuated IAV‐S vaccine have recently become available, which showed promising results in young pigs.ObjectiveThe aim of this study was to investigate the effect of an intranasal vaccination of newborn pigs with or without maternally derived antibodies (MDA) on virus shedding (via nasal swabs tested by virus isolation).MethodsThe study was performed as intratracheal challenge experiments with either a heterologous H1N2 or H3N2 viruses.Results and conclusionThe results of this study showed a significant decrease in the incidence and duration of shedding viable virus for vaccinated newborn piglets with or without MDA, providing strong evidence that intranasal vaccination is overcoming passively acquired maternal immunity. This study indicates that intranasal vaccination with a truncated NS1 live attenuated IAV‐S vaccine of newborn piglets with maternal antibodies can be a valuable tool for reducing the prevalence of heterologous H1N2 and H3N2 IAV‐S in pig herds.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen of swine. Due to genetic variation between the European and the US genotype as well as within both genotypes detection of PRRSV is a diagnostic challenge. This paper reports on a ring test to compare different established reverse transcriptase polymerase chain reaction methods applied routinely in 16 different laboratories in Germany. Three different sets of samples were sent to the laboratories which were to be analysed as follows: (i) basis package: detection of PRRS (yes/no); (ii) differentiation package I: differentiation of EU and US genotypes; and (iii) differentiation package II: differentiation of EU field isolates and EU vaccine strain. A total of 80% of the samples of the basic package were analysed correctly, the analysis of the differentiation package I revealed 61.82% correctly tested samples and the two laboratories that analysed the differentiation package II showed only one correct result. The ring test showed that the majority of incorrect diagnoses were false-negative results.

Background Influenza A virus in swine ( IAV ‐S) causes an acute respiratory disease of swine which results in great economic losses. A bivalent H1N1 and H3N2, NS 1‐truncated live‐attenuated IAV ‐S vaccine ( LAIV , Ingelvac Provenza ™ ) has recently become available. Objective Reduction of shedding during an outbreak in the nursery or finisher is an important parameter from an epidemiological control strategy; therefore, a laboratory efficacy study was conducted to evaluate nasal virus shedding when vaccinated pigs were challenged with either heterologous H1N2 or H3N2 strains 12 weeks post‐vaccination. Methods Between 1 and 5 days of age, pigs born to IAV ‐S seronegative dams were intranasally administered 1 mL of vaccine or saline. At 30 days post‐vaccination, pigs were weaned and randomized into two different challenge groups consisting of vaccinated pigs and control pigs commingled within pens for the two challenge groups. At 85 days post‐vaccination, pigs in the first group were challenged with A/Swine/North Carolina/001169/2006 H1N2 challenge strain, and the second group was challenged with A/Swine/Nebraska/97901‐10/2008 H3N2. Nasal swabs were collected daily for five days and tested by virus isolation. Results and conclusion This study showed significant reduction in nasal virus shedding with regard to both frequency and duration. A 1 mL intranasal dose of Ingelvac Provenza ™ given as early as 1 day of age showed protection for at least 12 weeks later as evidenced by the reduction of shedding live, viable virus after challenge with either a heterologous H1N2 strain or a heterologous H3N2 strain.

ObjectiveThe study aimed at investigating the occurrence of antibodies against the porcine pathogens Mycoplasma hyopneumoniae (M. hyo) and PRRS virus (PRRSV) in the serum of pigs aged 10 to 25 weeks and kept under field conditions in Germany. MethodologyAs part of a broad clinical trial comparing the efficacy of two M. hyo vaccines, serological investigations took place in 40 animals of the negative control group (subdivided into 2 subgroups of 20 animals each). As the case with the remainder of the control group, these animals had previously received a single administration of 2 ml isotonic saline deep intramuscularly in the neck at approximately 3 weeks of age. Blood samples were taken at the piglets' entry into the fattening unit (week 10 of age), in the middle of the fattening period (week 17 of age) and at the end of the fattening period (week 25 of age). Employing ELISA technology, the samples were investigated for both M. hyo and PRRSV antibodies. The pigs were not vaccinated against PRRSV. ResultsThe serological investigations revealed that at the first 2 sampling time points (10 and 17 weeks of age, respectively) no antibodies against M. hyo were present in the serum of the piglets. Only at 25 weeks of age M. hyo antibodies could be detected in 70% of the animals in subgroup 1 and in 75% of the animals in subgroup 2. On the contrary antibodies against PRRS virus were detected in the majority of the animals at all three sampling time points. Thus at 10 weeks of age 100% of the piglets tested positive for PRRS virus antibodies . Seven weeks later, the serum of all 20 animals in subgroup 1 and of 95% of the piglets in subgroup 2 contained antibodies against PRRS virus. The situation was similar at 25 weeks of age with 85% of pigs in subgroup 1 having antibodies against PRRS virus and 100% of animals in subgroup 2. ConclusionsThe serological results obtained in the negative control animals provide evidence that the herd was infected with Mycoplasma hyopneumoniae and that this infection occurred rather late in the fattening period, i.e. at around week 20 of age. Infection with PRRS virus was demonstrated already at the first investigation time point at 10 weeks of age. This is a common finding in swine production, which is known to favour subsequent infection with other porcine pathogens. Abstracts -Poster presentations at 11 th ICPD 275Acta vet. scand. Suppl. 98 -2003