ABSTRACT
Infectious bronchitis virus (IBV) is a leading cause of economic losses within the poultry industry, affecting both meat-type birds and layers. The highly contagious viral disease caused by Avian coronavirus was first described in the 1930s and still remains a global problem for the poultry industry. Infection by Avian coronavirus causes respiratory disease, nephritis, decreased egg production depending on the viral pathotype and the age of the affected flocks. Live attenuated and inactivated vaccines are used to control the disease, but poor cross-protection between different serotypes complicates control efforts. IBV exists in a wide variety of genetically distinct types and new variants are identified relatively frequently. As the emergence of new IBV variants may impede the efficacy of the vaccines, monitoring the prevalence and genetic characteristics of IBV is of utmost importance. Currently, a phylogeny-based classification system defined by Valastro and coworkers is used for the classification of IBV strains. At present, IBV strains are divided into 8 genotypes (GI-GVIII) and 39 distinct lineages (GI-1 to GI-31, GII-1, GII-2, GIII-1, GIV-1, GV-1, GVI-1, GVII-1 and GVIII-1) and a huge number of unclassified inter-lineage recombinants. Most IBV lineages are confined to specific geographic regions, and some countries report the circulation of unique lineages. In contrast, the GI-1, GI-13, GI-16 and GI-19 lineages are widely distributed. The aim of this review is to summarize the most recent knowledge about the distribution of the genetic groups of Avian coronavirus.
ABSTRACT
In this study, avian coronavirus infectious bronchitis virus (IBV), infectious laryngotracheitis virus (ILTV), avian metapneumovirus (AMPV), and avian reovirus (ARV) were evaluated in broiler and layer flocks. For this purpose, tracheal swabs from 48 broiler and 45 layer flocks with respiratory signs were inoculated SPF embryonated chicken eggs for virus isolation. The viruses were identified by real-time PCR. Results showed that the most common virus in both broiler and layer farms was IBV with incidence rates of 58.33% and 46.67%, respectively. ILTV, AMPV, and ARV incidences in the samples were found to be 22.22%, 13.33%, and 4.44% in layer flocks while 2.08%, 8.33%, and 20.83% in broilers, respectively. The numbers of IBV+AMPV and IBV+ARV coinfections were 5 (11.11%) and 1 (2.22%) in layers, whereas, 1 (2.08%) and 5 (10.42%) broilers, respectively. In addition, 2 broiler flocks (4.17%) had triple infection with IBV, AMPV, and ARV. ILTV was detected always alone from the samples of layer and broiler flocks. Sequencing of S1 gene of selected IBV TR/L45 and TR/B42 isolates showed similarities with IS/1494/06 (HM131453) at the rates of 98.98% and 99.69%, respectively, while TR/L37, TR/L38, and TR/L39 isolates were identical to 4/91 (KF377577) vaccine strain at the rates of 99.01%, 99.01%, and 98.76%, respectively. Sequencing analysis of the ICP4 and TK genes of ILTV isolates revealed that they were all field strains with low virulence. The present data represent actual information on the genotypes of IBV and ILTV circulating in poultry flocks in Turkiye.
ABSTRACT
Poultry enteritis is an important multifactorial disease. Avian coronavirus (ACV) is one of many viruses related to enteric diseases and infectious bronchitis. Aim of this study was to find out the occurrence of ACV in enteritis affected broiler, molecular detection, phylogenetic analysis of avian corona virus and to examine intestine and liver for gross and microscopic lesions. Dead poultry birds (N=604) affected with enteritis were examined for presence of ACV. Intestinal samples of four birds were pooled to make one biological sample enteric ACV as the causative agent of enteritis in commercial poultry sector in and around four major districts of Rajasthan by RT-PCR. Molecular characterization was carried out by partial gene sequencing. Liver and intestine were examined grossly during post-mortem and by histopathology. Out of 151 pooled samples tested 51 (35.10%) were found positive for ACV. Prevalence of enteric ACV was highest in Ajmer (45.94%) and lowest in Dungarpur (23.07%) districts. 0-1 weeks age chicken flocks were found more susceptible for enteric ACV with 33.80% prevalence. Comparison of ACV sequence of this study revealed nucleotide (nt) identities from 99.44% among themselves, 99.44% with ACV from abroad. The amino acid (aa) identities of ACV of this study among themselves and with abroad sequences was 47.06 to 100%. Further severe congestion in intestine and necrotic patches on liver were recorded. Histopathology showed severe villous atrophy, congestion and cystic glands in sub-mucosa in intestine and severe congestion and haemorrhages along with infiltration of inflammatory cells in liver parenchyma.
ABSTRACT
Invasive species are a growing concern with increasing global connectivity. Feral pigeons (Columba livia) are widespread and invasive, thus their effective control is of keen international interest. The COVID-19 pandemic has offered an unprecedented opportunity to investigate the impact of a nation-wide Circuit Breaker (restricted human activities) in Singapore on first, the abundance of the feral pigeons and three urban commensals-the Javan myna (Acridotheres javanicus), common myna (A. tristis), and house crow (Corvus splendens) in different food source types;and second, the activity budgets of feral pigeons. A significant and progressive decline in feral pigeon abundance was observed in open food centres and feeding hotspots after the Circuit Breaker was implemented. While the house crow and common myna were less affected, the Javan myna abundance increased moderately at refuse collection centres during the Circuit Breaker and decreased significantly in green spaces after the Circuit Breaker. Changes in food abundance could also predict changes in feral pigeon abundance and its effect was greatest in feeding hotspots. A greater proportion of feral pigeons was observed foraging and moving with a smaller proportion seen resting with probable consequences on their reproductive capacity. Our study also cautions against drawing inferences on biological responses due to similar social restrictions without careful consideration of other ecological factors, like average flock size and time of the day, which also affected the proportion of pigeons foraging on natural versus anthropogenic food. In summary, our results advocate a food limitation approach to control the feral pigeon populations.