Krzysztof Adamczyk

Lameness in poultry is a significant issue in modern meat production that adversely affects both animal welfare and economic outcomes due to poor leg health, reduced locomotor function, increased feed conversion ratios, and poor performance. Fast-growing broilers are particularly susceptible to lameness, with Staphylococcus being a major bacterial cause of skeletal infections. The aim of this study was to identify Staphylococcus species isolated from skeletal lesions in broiler chickens and to characterize the factors that facilitate such infections. Bacterial strains were isolated from 25 commercial broiler flocks in eastern Poland. The median prevalence of Staphylococcus in birds per flock was 60%. In total, 47% of the examined chickens and 88% of the examined flocks tested positive for Staphylococcus. The main bone sites affected by staphylococci were the femur (56.7%), femoral head (necrosis) (34.3%), hock joints (9.0%), femoral head (transient necrosis) (9.0%), tibiotarsus (7.5%), foot pads (dermatitis) (3.0%), and stifle (knee) joints (1.5%). Of all 93 Staphylococcus strains, 59% (55/93) were isolated from the femora. Twelve staphylococcal species were identified, all coagulase-negative, where Staphylococcus cohnii (24.7%) was the most prevalent species, followed by S. epidermidis (16.1%), S. hominis (15.1%), S. lentus (10.8%), S. saprophyticus (9.7%), S. chromogenes (8.6%), S. arlettae (4.3%), S. sciuri (4.3%), S. haemolyticus (2.2%), S. xylosus (2.2%), S. carnosus (1.1%), and S. gallinarum (1.1%). Eleven and six different staphylococcal species were implicated in the pathogenesis of femoral and tibiotarsal lesions, respectively. More than one Staphylococcus species was isolated from 47.8% of all Staphylococcus-positive chickens. Nearly all (97.8%) of coagulase-negative staphylococci isolates had biofilm-forming ability, but most of them were categorized as weak biofilm producers. The highest biofilm production was observed in the strains that caused femoral head osteonecrosis and footpad dermatitis. Staphylococcus chromogenes, S. lentus, and S. epidermidis exhibited the highest DNase and/or gelatinase activity. Despite the low prevalence of certain adhesin genes, the eno gene encoding laminin-binding protein was highly represented in staphylococci (75.3%). The study highlights the complex nature of coagulase-negative staphylococcal infections in poultry and underscores the need for further research into their virulence mechanisms and control strategies.

Background: Pigeon Rotavirus A (RVA) infection has been confirmed in pigeons in the last decade as a cause of Young Pigeon Disease (YPD). Although YPD has been known for many years to date, no studies have been conducted to track the spread of RVA infection in pigeons during the racing season. The presented research aims to determine the course of RVA infection during the flights of young racing pigeons in the summer season, in one of the districts in the Mazovian Voivodeship in Poland. Results: Faecal samples of pigeons collected from transport baskets in vehicles transporting pigeons to the starting point were tested. The quantitative RT-PCR (qRT-PCR) was used to detect the genetic material of RVA. Samples taken during 6 flights were analysed. The study showed a percentage increase in infections up to the fourth flight of pigeons, and then their decrease. With Cq values below 20, breeders did not participate in the next flight and/or reported disease in the flock. With positive Cq values of 20 to 30, clinical signs of disease were not reported. Of the 76 breeders participating in the races, at least one positive result was found in 46 (60.5%). Including the occurrence of the disease during the racing season was reported by 11 breeders (14.4%). The main clinical signs in sick pigeons were vomiting, diarrhea and stowed crop. The tested pigeons were not vaccinated against RVA. Conclusions: During training and racing of pigeons, it is not possible to avoid exposing them to pathogens, including RVA, regardless of whether pigeons from different breeders are placed in the same baskets or are in separate baskets. However, after four flights the number of new cases of the disease decreases which indicates the development of immunity. The qRT-PCR test is useful in the diagnosis and differentiation of clinical (Cq below 20) and subclinical RVA infections in racing pigeons.

Introduction: Although the presence of rotaviruses in pigeon samples has been reported since the 1980s, its importance as an aetiological agent of the “classical” young pigeon disease (YPD) was not proven until 2020, when the Henle–Koch postulates were confirmed for pigeon-type rotavirus A (RVA) genotype G18P(17). Material and Methods: From 2011 to 2020, archived liver samples from 117 pigeons submitted by 74 individual lofts were tested for the presence of pigeon-type RVA using a VP6-specific RT-qPCR test. For four positive racing pigeons, a more detailed necropsy and histopathological analysis was performed. Results: Indicators of an acute RVA infection were found in 24 out of 117 (20.5%) samples tested, the earliest in 2014. Necropsies of the four selected RVA-positive pigeons showed changes mainly in the liver, spleen and kidneys similar to those described by other researchers. The histopathological examination revealed mainly hyperaemia and necrosis in the liver, as well as mononuclear cell infiltrates in these organs. Conclusion: Pigeon-type RVA is also a cause of YPD in Poland and is a serious challenge for racing pigeon breeders and veterinarians, especially during the training and flights of young pigeons.