Veterinarija ir Zootechnika

Infectious laryngotracheitis (ILT) is a respiratory viral infection, particularly common in adult chickens. The disease widely distributed in several countries causes severe economic losses. ILT virus (ILTV) is a double-stranded DNA which belongs to Alphaherpesvirinae subfamily of Herpesviridae family. Infected and latently carrier chickens are sources of ILTV infection, while the aerosol is the main route of the virus transmission. The acute epizootic form of ILT is characterized by a sudden onset, a rapid spread, and a high mortality rate with severe conjunctivitis, dyspnoea, gasping, coughing, expectoration of blood mixed with mucus, and drop in egg production. However, chickens in the mild enzootic form show less signs with a morbidity rate up to 5% and a mortality rate between 0.1% and 2%. The most characteristic post-mortem lesions are haemorrhagic tracheitis with the presence of a yellow cheesy plug in the respiratory tract. Despite diagnostics of signs and lesions, the confirmation of ILTV infection occurs via conventional isolation, detection of the virus in the affected tissues, as well as using recent molecular techniques. Prevention of ILTV infection depends on some key lines, including biosecurity measures and vaccination. Both live attenuated and recombinant vaccines are used for the prevention and control of ILTV infection. Therefore, the present review focuses on susceptibility, transmission, clinical picture, diagnosis, differential diagnosis, immune response, and prevention and control.

Pigeons are highly susceptible to Newcastle disease virus (NDV) infection, which causes economic losses in terms of increased mortalities, immunosuppression, vaccination costs, and probable trade restrictions. NDV belongs to the avian paramyxovirus serotype 1 (APMV-1). The antigenic variant of APMV-1 is termed as pigeon paramyxovirus type 1 (PPMV-1), which is classified in the genus Avulavirus of the subfamily Paramyxovirinae and family Paramyxoviridae. Infections of pigeons with PPMV-1 have been detected since the 1930s, and the virus is still circulating in many countries until now. Domestic, feral, and racing pigeons, doves, and exotic birds are susceptible to PPMV-1 infection. The virus is rapidly spreading between birds through the horizontal route. Infected pigeons may show circling, ataxia, torticollis, head and neck tremors and twisting, leg and wing paralysis, greenish diarrhea, respiratory signs, and polyuria. Some pigeons could be infected with PPMV-1 without apparent signs, and they act as reservoirs for other domestic or free-living birds. The diagnosis of suspected PPMV-1 cases is based mainly on the isolation and identification of the virus, serological detection of specific antibodies, and molecular characterization of the virus. Adoption of strict biosecurity measures as well as vaccination using traditional live or inactivated NDV or even the specific PPMV-1 vaccines are the gold standard methods for preventing pigeons from such infection. Therefore, this review article was designed to focus on PPMV-1 infection regarding the virus characteristics, epidemiology, diagnosis, human infection, and control.