Occurrence of Aviadenovirus in chickens from the poultry industry of Minas Gerais

C.G. Pereira,A.M. Gomes,B.M. Santos,M. Resende,S.Y. Marin,J.S. Resende,N.R.S. Martins

doi:10.1590/1678-41625899

Abstract

The occurrence of Aviadenovirus (FAdV) was investigated in chickens from the poultry industry of Minas Gerais state, Brazil. The investigation was conducted due to the scarcity of recent data in the country and its description in neighboring countries. For this purpose, livers were collected from layer chicks (n=25), older layers (n=25), broilers (n=300), and livers (n=25) and stool (n=25) samples from broiler breeders, representing the major poultry regions of the state. FAdV DNA was demonstrated using a previously described PCR protocol for amplifying part of the hexon gene encoding sequence. FAdV was found in layer chicks (36%), widespread (100%) in older layers, and with regional differences in broilers (24-86%). Although all broiler breeder stools were negative, FAdV DNA was detected in livers (16%, 4/25) of stool-negative birds. In order to obtain additional information on the circulation of the infection, livers of subsistence chickens collected from one poultry intensive region, were evaluated (n = 12), with FAdV being detected in all samples. FAdV was found in young and old layers, broilers, broiler breeders and free-range chickens, and results suggest the circulation of FAdV among different types of chickens. The detection in older layer chickens may indicate an extended risk of horizontal transmission in regions of Minas Gerais with mixed activity of egg and meat type chickens and poor biosecurity strategies. The infection in breeders may indicate vertical transmission and the continuous production of infected progenies. The hexon-gene-targeted PCR amplicon sequences aligned with FAdV of species D of Aviadenovirus. Results indicate the necessity for biosecurity, especially for breeders, separating flocks according to origin, age and health status, which will be an advantage regarding any pathogen.

Highlights

Aviadenovirus are members of Adenoviridade genus which includes seven adenovirus geese and hawk virus species designated A, B, C, D and E
The polymerase chain reaction (PCR) protocol used in this study enabled the detection of the target genomic segment in the total DNA diluted up to 10-9 on the positive FAdV Phelps strain used as control
Two FAdV isolate sequences encoding for the hexon protein including the L1 loop region were analyzed and strains were grouped into the D species of Aviadenovirus, together with a previously described serotype 11 in Brazil

Summary

Introduction

Aviadenovirus are members of Adenoviridade genus which includes seven adenovirus geese and hawk virus species designated A, B, C, D and E. In Gallus gallus domesticus, the prototype is FAdV (Fowl Adenovirus type 1), and may further be characterized into 13 serotypes (International...,). Adenoviruses have worldwide distribution and appear to be ubiquitous in the poultry population (Adair and Fitzgerald, 2008). A feature of the FAdV epidemiology is the unusually large number of serotypes that can be isolated on a farm. It is not uncommon to isolate two or more serotypes from the same bird (Hess et al, 1999), suggesting that there is little cross-protection among serotypes (Adair and Fitzgerald, 2008). Poultry industry, which primarily affects broiler chickens at 3-6 weeks of age and is characterized by sudden onset and high mortality (Abdul-Aziz and Hasan, 1995). A FAdV investigation in 28 poultry vaccines, 26 live and 2 inactivated, was published recently (Barrios et al, 2011), and found FAdV

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