Bordetella avium is a gram negative, nonfermentative, strictly aerobic, motile bacterium from the genus Bordetella which has been isolated from patients with respiratory disease (cystic fibrosis). B. avium has a global distribution. The disease in birds is called bordetellosis, and is largely associated with confined spaces and multi-aged flocks where management practices are sub optimal. In most infections, mortality is typically low but morbidity is very high.
Who can get Bordetella avium ?
Although birds of all ages are susceptible, prevalence is highest in younger birds 1–6 weeks old. It is thought that birds who reach 5–6 weeks of age become relatively resistant to the clinical disease bordetellosis, yet, they can remain carriers among the flock. In addition, much of the transmission is thought to relate to management practices and outbreaks are often associated with confined spaces.
Although less common, B. avium can also transmit to wildlife species where prevalence is still being evaluated. It has been suggested that wildlife species act mainly as a reservoir and it is unclear if B. avium acts as part of the normal flora in wild bird populations or is a causative agent of disease. Despite the fact that wild birds are commonly asymptomatic, Bordetellosis has been reported in a variety of wild birds including parrot finches, partridges, and cockatiels. As the severity of disease increases the most common comorbidity associated with Bordetella avium is a secondary infection with E. coli. B. avium is also thought to decrease an individual’s ability to clear secondary organisms from the trachea which allows them to set up an infection.
Transmission of Bordetella avium
Cockatiels also have been shown to develop the disease but it has not yet been studied to determine how the disease presents in these birds. The pathogenesis of B. avium is through fimbrial attachment to the respiratory epithelium and release of a variety of virulence factors, leading to respiratory symptoms, such as sneezing, ocular and nasal discharge, and inflammation.
Signs and Symptoms of Bordetella avium
Environmental contamination is an important route of infection for B. avium. B. avium can survive in the environment less than 2 days at higher temperatures (40 °C), up to a month with low temperature (10 °C) and humidity (32-58%), and up to 6 months in feed, water and damp litter. Good bio-security protocols, thorough cleaning, and excellent practices are the best methods for controlling outbreaks. Optimal temperature, humidity, and control of ammonia and dust are critical to reduce B.avium growth in the environment and reduce irritants to the tracheal epithelium. Most common disinfectants used do kill B. avium, and thorough cleaning includes removal of litter and other fomites between flocks, disinfection of the cage and flushing of water lines with disinfectants, and fumigation with methyl-bromide or formaldehyde. Foot baths, preventing contact with wild birds. For infected flocks, increasing ventilation and reaching optimal temperature are key. It has been reported that niacin or 0.016% oxy-halogen added to water lines given early in life reduces the severity of bordetellosis.