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Infectious bronchitis virus (IBV) is a great economic burden both for productive losses and costs of the control strategies. Many different vaccination protocols are applied in the same region and even in consecutive cycles on the same farm in order to find the perfect balance between costs and benefits. In Northern Italy, the usual second vaccination is more and more often moved up to the chick's first d of life. The second strain administration together with the common Mass priming by spray at the hatchery allows saving money and time and reducing animal stress. The present work compared the different vaccine strains (Mass-like or B48, and 1/96) kinetics both in field conditions and in a 21-day-long experimental trial in broilers, monitoring the viral replication by upper respiratory tract swabbing and vaccine specific real time reverse transcription PCR (RT-PCR) quantification. In both field and experimental conditions, titers for all the vaccines showed an increasing trend in the first 2 wk and then a decrease, though still remaining detectable during the whole monitored period. IBV field strain and avian Metapneumovirus (aMPV) presence also was also investigated by RT-PCR and sequencing, and by multiplex real-time RT-PCR, respectively, revealing a consistency in the pathogen introduction timing at around 30 d, in correspondence with the vaccine titer's main decrease. These findings suggest the need for an accurate knowledge of live vaccine kinetics, whose replication can compete with the other pathogen one, providing additional protection to be added to what is conferred by the adaptive immune response.

Infectious bronchitis (IB) control has a strong impact on poultry farming, because of the necessary epidemiological knowledge for planning the best strategy, the optimal strain association, the priming and boosting interventions. Broiler farming is even more problematic given the short and intense productive cycle, which requires an early onset of protection against most of the infectious threats, possibly with limited respiratory post-vaccination reactions that would have a direct impact on the bird health and productivity. For this purpose, gel vaccination has been proposed as a new approach for infectious bronchitis virus (IBV) control and vaccine intake, kinetics and compatibility of combined strains administered by gel have been analyzed in this study. After gel vaccination with single and combined 1/96 and B-48 strains on 4 groups of commercial broilers, a 21-d-long experimental trial has been conducted to monitor the vaccine safety by clinical assessment and vaccine kinetics by strain-specific real-time RT-PCR on choanal cleft swabs. The vaccine strains administered by gel were safe and negligible respiratory signs were detected, even when combined. Vaccine titers were compared among groups and within the same group among a 10-bird pooled sample and 10 swabs from individually sampled birds. 1/96 strain early reached high titers in all animals, while B-48 presence was less constant even though it was detected in almost all birds before the trial end. The individual and pooled sample comparison revealed a partial overestimation of vaccine titers in the pooled samples and the loss of the prevalence data, although the trend portrayed by the pooled swabs closely followed the individual ones.

One hundred and six Clostridium perfringens field strains, isolated from diseased turkeys in Italy between 2006 and 2015, were toxinotyped by polymerase chain reaction. Strains were derived from intestines (87), livers (17) and subcutaneous tissues (2). In addition to the four major toxins, strains were also screened for NetB toxin, enterotoxin and beta2 toxin encoding genes. The intestinal gross lesions of turkeys with enteric disorders were statistically studied with respect to the presence of C. perfringens beta2 toxin encoding gene and coccidia in the gut. All the isolates belonged to the toxinotype A and were netB negative. Enterotoxin (cpe) and beta2 toxin (cpb2) encoding genes were detected in two (2.63%) and 76 (71.69%) strains, respectively. Toxinotype results agree with the few published reports concerning the genetic characterization of C. perfringens of turkey origin. On the contrary, the presence of netB and cpb2 genes differs from the results of a previous study where these genes were detected respectively in 6.6% and in 0.5% of the tested strains. Necrotic enteritis in turkeys was not statistically correlated either to the presence of cpb2 gene, or to the synergistic effect operated by coccidia, even though a high percentage of birds with these protozoa in the gut showed necrotic enteritis lesions (64.29%).