Survey of infectious laryngotracheitis outbreak in layer hens and differential diagnosis with other respiratory pathogens

Abstract

Trachea, lung, and conjunctive samples from 51 commercial layer farms from Bastos region, São Paulo, Brazil, were submitted to nested-PCR and virus isolation in SPF chicken embryos for ILT diagnosis. This region experienced an outbreak characterized by respiratory signs, decrease in egg production and increased mortality. Out of the 51 tested field samples, 23 were positive for ILT by nested-PCR, 22 were positive after the virus isolation, and 24 were positive when both techniques were used. Newcastle disease virus, Avian pneumovirus, or Mycoplasma gallisepticum were not detected. Infectious bronchitis virus was detected in one farm and Mycoplasma synoviae was detected in eight farms. The high incidence of infectious laryngotracheitis virus (ILTV) detection, the high correlation between the observed clinical signs and the ILTV detection, and the results of differential diagnosis demonstrated that ILTV was the causative agent of the outbreak of respiratory disease observed in Bastos region, São Paulo, Brazil.

Histopathology in diagnosis of broiler chicken and layer diseases – review of cases 1999-2010

“…Additionally, in the present study a few cases of ILT were noted, occasionally in layers, but some authors emphasize that these cases are more frequent (Chacón et al 2007); however, in the cited paper a definitive diagnosis was based on PCR or ELISA. There are some reports from the literature which indicate a highly comparable specific between the histopathology and PCR or immunofluorescence test in the diagnosis of ILT (Goodwin et al 1991, Humberd et al 2002.…”

“…Generally, lesions in the upper respiratory tract including inflammatory process were diagnosed as nonspecific tracheitis and, according to the literature, were commonly found in poultry in Poland and world-wide (Radkowski et al 1996, Chacón et al 2007). Additionally, in the present study a few cases of ILT were noted, occasionally in layers, but some authors emphasize that these cases are more frequent (Chacón et al 2007); however, in the cited paper a definitive diagnosis was based on PCR or ELISA.…”

“…For many years traditional virus isolation has been considered a gold standard for ILT diagnosis; however, it is a long-term and expensive method for routine diagnostics. Recent note that expedited histopathology and molecular detection have become the new gold standards for ILT diagnosis, since they both allow for a more rapid and effective approach (Humberd et al 2002, Chacón et al 2007). The mean age of affected birds was similar to data in the literature (Koncicki and Minta 2011a).…”

Occurrence of infectious Laryngotracheitis Virus (ILTV) in 2009-2013 in the State of São Paulo - Brazil

“…This is suggested by the detection of ILTV in uncommon organs and indicates that the pathogenesis of the disease is not well understood. Several studies using molecular techniques, such as PCR for detection of ILTV (Chacón et al, 2007;Chacón & Ferreira, 2008;Clavijo & Nagy, 1997;Crespo et al, 2007), prove that these techniques are very sensitive and specific. In the present study, a reaction of nested-PCR, oriented to the amplification of part of the gene encoding glycoprotein E, was successfully used to investigate the presence and tissue location of ILTV in layer chickens.…”

“…Molecular techniques, such as polymerase chain reaction (PCR), have been successfully used for the detection of ILTV in respiratory and other organs (Chacón et al, 2007;Oldoni et al, 2009;Rodríguez Avila et al, 2007). Polymerase chain reaction presents high sensitivity and specificity for the detection of ILTV.…”