Evaluation of respiratory route as a viable portal of entry for Salmonella in poultry

Abstract

With increasing reports of Salmonella infection, we are forced to question whether the fecal-oral route is the major route of infection and consider the possibility that airborne Salmonella infections might have a major unappreciated role.

In ovo Administration of Defined Lactic Acid Bacteria Previously Isolated From Adult Hens Induced Variations in the Cecae Microbiota Structure and Enterobacteriaceae Colonization on a Virulent Escherichia coli Horizontal Infection Model in Broiler Chickens

“…Several studies have indicated that this method does not alter hatchability, improves intestinal health, and favors microbial diversity ( 3 – 5 ). Furthermore, in ovo delivery of probiotics may have a significant impact in commercial poultry because hatching cabinets represent one of the first potential sources of pathogenic enterobacteria ( 6 , 7 ). Avian pathogenic Escherichia coli (APEC) may also penetrate the shell ( 8 ) or can be vertically transferred ( 9 ), causing significant mortality during the first week ( 10 ).…”

Respiratory and Gut Microbiota in Commercial Turkey Flocks with Disparate Weight Gain Trajectories Display Differential Compositional Dynamics

“…In other poultry, different respiratory sites are known to house distinct bacterial communities that develop with age (26,27,31,32), but the contribution of these communities to poultry health is largely unknown. Of particular interest is the microbiota of the upper respiratory system (the nasal cavity and the trachea), as these sites are among the first points of contact for airborne bacteria, including aerosolized fecal bacteria (33). Understanding how upper respiratory microbiota develops alongside gastrointestinal microbiota is critical to the development of effective interventions against transmission of performance-inhibiting microorganisms and to improve poultry health and productivity.…”

A critical assessment of the cellular defences of the avian respiratory system: are birds in general and poultry in particular relatively more susceptible to pulmonary infections/afflictions?

“…According to Linder & Sisson (1994) and Corley et al (2012), in the mammalian lung most pathogens and particulates are trapped before they reach the alveoli, thus the arrangement of the airways constitutes a non-specific defence system. Kallapura et al (2014) observed that infections of the avian respiratory system predominantly occur in the caudal air sacs because inhaled air loaded with foreign matter flows directly to the caudal air sacs (Fig. 3A,E).…”

“…In pulmonary attacks, pathogens may disseminate from there to other parts of the body (Bosch et al, 2013;Koppen et al, 2015;Hakansson, Orihuela & Bogaert, 2018). In chickens (Gallus gallus variant domesticus), Kallapura et al (2014) observed that the respiratory tract may have been underestimated as a portal of entry of Salmonella infections. For gas exchange by passive diffusion, the BGB of lungs of birds is exceptionally thin Maina, 1989Maina, , 1993Maina, , 2005Maina & West, 2005): the BGB considerably exposes the body to attacks and injuries by pathogens and foreign agents (Hendrickson & Matthay, 2013;Clementi et al, 2021).…”

“…Regarding the avian respiratory system, Mutua, Muya & Gicheru (2016) speculated that its remarkably complex morphology (McLelland, 1989;Maina, 2005Maina, , 2022Powell, 2014) and elaborate airflow dynamics (Scheid, 1979;Banzett et al, 1987Banzett et al, , 1991Kuethe, 1988;Wang et al, 1988Wang et al, , 1992Maina & Africa, 2000;Maina, Singh & Moss, 2009) would increase the possibility that pathogens and particulates are deposited along the intricate avian airway (bronchial) system. Kallapura et al (2014) conjectured that the architecture of the avian respiratory system is an important contributor to susceptibility and resistance to infectious agents. Van Alstine & Arp (1988) and Fagerland & Arp (1993a) attributed the lack of well-organised bronchus-associated lymphoid tissue (BALT) in the cranial part of the avian lung and its presence at the orifices of the distal secondary bronchi, especially in species such as chicken and turkey (Meleagris gallopavo), to the airflow pattern in the avian lung, where inspired air travels directly to the caudal part of the respiratory system, bypassing some of the airways (Scheid, 1979;Van Alstine & Arp, 1988;McLelland, 1989;Fagerland & Arp, 1993a,b).…”