Common viral and bacterial avian respiratory infections: an updated review

Abstract

Many pathogens that cause chronic diseases in birds use the respiratory tract as a primary route of infection, and respiratory disorders are the main leading source of financial losses in the poultry business. Respiratory infections are a serious problem facing the poultry sector, causing severe economic losses. Avian influenza virus, Newcastle disease virus, infectious bronchitis virus, and avian pneumovirus are particularly serious viral respiratory pathogens. Mycoplasma gallisepticum, Staphylococcus, Bordetella avium, Pasteurella multocida, Riemerella anatipestifer, Chlamydophila psittaci, and Escherichia coli have been identified as the most serious bacterial respiratory pathogens in poultry. This review gives an updated summary, incorporating the latest data, about the evidence for the circulation of widespread, economically important poultry respiratory pathogens, with special reference to possible methods for the control and prevention of these pathogens.

Keywords: avian respiratory pathogen; clinicopathological characteristic; disease control; poultry; vaccine.

Graphical abstract

Figure 1

Most common avian respiratory tract infections caused by viruses and bacteria.

Figure 2

Infectious bronchitis syndrome and its clinical signs and pathognomonic postmortem lesions of different forms (respiratory, renal, and reproductive).

Figure 3

The transmission of avian Mycoplasma, by both vertical route from infected chickens to its progeny, and horizontal route from infected chickens to susceptible chickens.

Figure 4

Avian chlamydiosis host range (pigeons, ducks, turkey, chickens, and psittacine birds) with its zoonotic importance.

Figure 5

Clinical and pathological forms of Escherichia coli infection in poultry including air sac infection, septicemic and localized infections.

Figure 6

Clinicopathological forms of infectious coryza. This disease is characterized by high morbidity but low mortalities with upper respiratory tract signs including (nasal discharge, swelling in infraorbital sinus, catarrhal sinusitis, facial edema, lacrimation, tracheitis) with an adverse impact on egg production including lowering the egg production up to 40% and in some cases, diarrhea was recorded.