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The outbreaks of pandemic H1N1 influenza A virus (pdm-like H1N1 2009), detected for the first time in farrow-to-finish farms in Poland, were described. The nasal swabs and lung tissue collected from diseased/dead animals were tested using molecular techniques (RRT-PCR, MRT-PCR, RT-PCR, SSG-PCR, sequencing) and virus isolation. The amplification of the genetic material extracted from the tested samples confirmed the presence of the M1 gene sequence of type A influenza virus. Using MRT-PCRs no products characteristic for HA and NA of any swine influenza virus subtypes were obtained. Using SSG-PCR, products specific for pandemic HA and NA gene fragments were detected. Six new pdm-like H1N1 2009 strains were isolated and characterised. Phylogenetic analysis of the HA and NA genes revealed that they belong to one lineage with the pandemic strain A/California/04/2009 and other human strains, including human strains isolated in Poland in 2011.

The efficacy of toltrazuril treatment was assessed in two experiments in Polish swine herds. Experiment 1 included a toltrazuril treatment group, Group A (n = 410), and untreated control, Group B (n = 386). Time to sale in Group A was 108 days versus 120 days for Group B, with average body weights at sale of 114.2 kg and 108.8 kg, respectively (P < 0.05). In experiment 2, the health status and body weight gain of 238 piglets treated with toltrazuril (Group D) were compared to 235 untreated piglets (Group K). A similar difference was observed in average body weights of slaughtered animals, being on average 104 kg in Group D and 101 kg in Group K (P < 0.01). Animals from Group D were slaughtered 5 days earlier than animals from Group K (day 166 versus day 171). Data from clinical trials suggest treatment of coccidiosis with toltrazuril offering potential for improved animal welfare and yields, however this has remained unproven in field conditions in large swine production facilities. The present study confirms the efficacy of toltrazuril treatment when used in the field and the subsequent positive impact on time to weaning, time to market, and on weight gain at all time points.

In a newly established farrow-to-finish farm (porcine reproductive and respiratory virus [PRRSV]-free, porcine circovirus type 2 [PCV-2]-infected), reproductive failure was seen seven months after population. The conception rate dropped from 89 to 51 per cent, and the abortion rate increased from 0.5 to 11 per cent. The following month, characteristic lesions of postweaning multisystemic wasting syndrome (PMWS) and elevated mortality were observed in weaned pigs. Laboratory examinations confirmed reproductive failure due to PRRSV and PMWS associated with apparent activation of the PCV-2 circulating in the farm. The herd was closed for replacement and a number of measures to improve hygiene, environmental conditions and feeding were applied. The abortion rate returned to preoutbreak levels four months after the beginning of the PRRS outbreak and the conception rate returned to normal four months later. Slower improvement was observed regarding the PMWS outbreak, with PMWS-related losses disappearing nine months after the detection of PMWS. Analysis of seroconversion profiles to PCV-2 and PRRSV during the outbreak and after its control indicated that while PRRSV was eliminated from sows and weaners by the control measures, the time of PCV-2 infection was unchanged and occurred at seven weeks of age during the PMWS outbreak as well as after its elimination. However, the elimination of PMWS from the herd coincided with increased levels of maternally derived antibodies to PCV-2 in one- to five-week-old pigs and faster serological responses to infection with PCV-2.