Molecular detection and characterization of infectious laryngotracheitis virus (Gallid herpesvirus-1) from clinical samples of commercial poultry flocks in India

Abstract

Although the existence of infectious laryngotracheitis virus (ILTV) in India was first reported in 1964, no reports are available regarding its molecular detection and characterization. The present study was aimed to detect and characterize ILTV from recent respiratory disease complex (RDC) outbreaks of commercial poultry flocks in different parts of the country by using envelope glycoprotein G gene (US4 gene) based PCR and sequencing. A total of thirty two flocks with a history of RDC were investigated. Overall, all the strains/breeds of birds and all ages of birds are equally susceptible and depending on the severity, the clinical signs and gross lesions were varied. Out of 32 flocks investigated 10 were found positive for ILTV infection by PCR. The phylogenetic analyses of eight representative sequences in the present study deciphered that Indian ILT viruses are closely related to chicken embryo origin vaccine strains of Italy, USA, China and Brazil.

Infectious Laryngotracheitis in Layer Birds from Tamil Nadu, India

“…After these initial reports, the disease was not reported from India for about more than 35 years. In recent years, the existence of this viral pathogen was confirmed through various studies especially in Namakkal district of Tamil Nadu state of India where a major share of poultry population of the country is maintained for commercial purpose (Srinivasan et al, 2012;Gowthaman et al, 2014;Puvarajan et al, 2014;Sivaseelan et al, 2014).…”

“…A hot and humid climatic condition prevails in the study area of Namakkal district round the year. The disease cases were reported all round the year, especially, in summer and winter followed by rainy season in the present report, very similar to the study, where the disease has been reported in the same agro-climatic zone throughout the year viz., winter, spring, summer and even in rainy season (Gowthaman et al, 2014). However, in another study, seroprevalence was reported higher in winter (24%) compared to rainy (16%) and summer (12%) seasons in the neighbouring country Bangladesh (Uddin et al, 2014).…”

“…The disease was first reported in India in 1964 (Singh et al, 1964) and subsequently, by many earlier reports (Panda and Singh, 1967;Ahmed et al, 1969). Presently, the disease status has gained momentum as evidenced by recent reports Infectious Laryngotracheitis in Layer Birds from Tamil Nadu, India (Srinivasan et al, 2012;Gowthaman et al, 2014;Sivaseelan et al, 2014) especially in the Namakkal district of Tamil Nadu state of India. The Namakkal is popularly known for commercial poultry production in India.…”

Infectious laryngotracheitis: Etiology, epidemiology, pathobiology, and advances in diagnosis and control – a comprehensive review

“…Yellow caseous exudates (cheesy plug) also observed in primary bronchi when the lesions extend deeply (OIE 2014). In the acute form, yellow caseous diphtheritic membranes adherent to the larynx and mucosa of the upper trachea with or without haemorrhages are commonly noticed (Gowthaman et al 2014). The membrane also forms obstructive plugs in the larynx and syrinx regions leading to suffocation and death.…”

“…Apart from tracheal involvement, conjunctivitis is characterized by edema and congestion with increased ocular discharge (Hinshaw et al 1931;Kirkpatrick et al 2006). The inflammatory response in nares is characterized by heterophilic exudates (Gowthaman et al 2014). The involvement of lungs and air sacs are rare.…”