Infectious laryngotracheitis: a review

Abstract

Infectious laryngotracheitis (ILT) herpesvirus continues to cause outbreaks of respiratory disease in chickens world-wide. Sporadic cases of ILT occur in all classes of birds, including hobby/show/game chickens, broilers, heavy breeders, and commercial laying hens. These epornitics of ILT tend to occur where there are large populations of naïve, unvaccinated birds, i.e., in concentrated areas of broiler production. ILT virus can be transmitted through (a) chickens with acute upper respiratory tract disease, (b) latently infected "carrier" fowls, and (c) fomites and contaminated persons. Chicken flocks which are endemic infected with ILT virus occur only in some regions of countries or even in particular multiple-age production farms. In these cases modified live vaccines are actually used, even though these biological products, as well as wild ILTV strains, can establish latent infections. In the case of heavy breeders and laying hens, which are typically vaccinated against ILT, sporadic cases are often related to errors in vaccine application and to biosecurity failures

Epidemiology of Avian Infectious Laryngotracheitis with Special Focus to South America: an update

“…In the first half of 2005, four cases of laryngotracheitis were recorded (http://www.midiatecavipec.com/avicultura/ avicultura020908.htm). ILTV was also reported in Uruguay, Colombia and Chile (Hidalgo, 2003;Back & Leão, 2003).…”

Diagnosis of a naturally occurring dual infection of layer chickens with fowlpox virus and gallid herpesvirus 1 (infectious laryngotracheitis virus)

“…ILT is controlled by vaccination, and there are two types of vaccines used commercially: the chicken embryo origin (CEO) vaccines, such as the SA2 vaccine; and the tissue culture origin vaccines (TCO), such as the A20 vaccine. However, the CEO vaccines may demonstrate residual virulence that can cause conjunctivitis and mortality in young birds, and is recommended for use in older birds or as a booster after vaccination with TCO vaccines (Guy et al, 1991;Hidalgo, 2003;Sellers et al, 2004). Restriction fragment length polymorphism (RFLP) of amplified segments of the thymidine kinase (TK) gene (Neff et al, 2008) and glycoprotein genes (Kirkpatrick et al, 2006) has been used to differentiate field isolates from vaccine strains.…”

Esophagitis and Pharyngitis Associated with Avian Infectious Laryngotracheitis in Backyard Chickens: Two Cases

“…This is the 264 first time that ILTV is detected by PCR and/or by IHC in the upper digestive tract of a 265 bird, in association with compatible microscopic lesions, thus confirming that the virus, 266 under certain conditions, could not only infect, but also replicate in and damage other 267 types of cells than the conjunctival and respiratory epitheliums. 268 269 14 Atypical lesions in the esophagus and pharynx with concomitant typical ILT lesions in 270 the larynx of these birds could raise the hypothesis that they were co-infected by two 271 different viruses, ILTV (as demonstrated by PCR and sequencing in case 1) and another 272 herpesvirus that could have been undetected by the precedent methods. In fact, other 273…”

“…Infectious laryngotracheitis (ILT) was first recognized as a disease in the 1920's and was 42 associated with clinical signs of the upper respiratory tract in chickens. The infectious 43 laryngotracheitis virus (ILTV) is classified in the Herpesviridae family of the 44 Alphaherpesvirinae subfamily, genus Iltovirus and identified as Gallid herpesvirus 1 45 (GaHV-1) (14,18). Chicken is the natural primary host of this virus, which has also been 46 reported in pheasant, partridge, young turkey and peafowl (7,19).…”