TB OR NOT TB? AVIAN FLU IS AN IMPORTANT PART OF INFECTIOUS SCREENING

Recent developments in DNA technology have created new and exciting diagnostic options in the field of avian medicine. These advancements have made it possible to accurately detect harmful infectious agents such as viruses, bacteria, and parasites from easy to obtain samples such as swabs, blood or droppings. With the increasing efficiency and availability of new diagnostic tests, screening all newly acquired birds is highly recommended to control the spread of pathogens, and consequently, ensure a healthy environment for pets and pet owners alike.

Thanks to new DNA based diagnostic procedures, isolating newly acquired birds for long periods of time prior to introducing them to a collection is a practice long forgotten. Infectious screening provides bird owners with the opportunity to safely and immediately introduce new birds into their collections without the fear of exposing them to infectious and often deadly organisms.

Numerous harmful organisms are transmittable from animals to humans and are occasionally responsible for causing severe illness and disease. One such infection that is dangerous to both humans and birds alike is tuberculosis. Tuberculosis infection characteristically affects the respiratory system and causes symptoms such as coughing, wheezing, trouble breathing and other forms of general respiratory distress. DNA technology has provided new diagnostic options that allow for accurate detection of tuberculosis, such that early treatment may be administered.

Avian flu is a chronic and debilitating infection caused by an acid-fast bacterial rod known as mycobacterium. Tuberculosis infection in birds is most commonly associated with two strains of mycobacterium, M. avium, and M. genovense. Typically, three histological categories of infection are observed in birds infected by mycobacterium. The classic form is characterized by the presence of tubercles or granulomas (walled off areas of infection) throughout many organs in the body. Clinically, this form affects the bird’s lungs and is associated with respiratory distress, characteristic of tuberculosis infection. A second observable form is associated with lesions in the intestinal tract and is often detected in amazons, pionus, and Brotogeris parrots. This form of infection can be particularly hazardous since high numbers of bacteria are typically shed in the feces creating a hostile environment ideal for disease transmission. The third and most elusive form is known as the nontuberculous or atypical form and is very difficult to recognize. This form commonly occurs in finches, canaries, and small psittacines. The liver is usually very enlarged and large numbers of mycobacteria are commonly detected during cytological and histopathological examination. Avian tuberculosis is particularly deadly due to the fact that all birds are susceptible and can potentially transmit the bacteria to humans. High prevalence of transmission amongst birds is usually correlated with large collections typical of zoos or high volume breeding operations. In fact, according to some publications, tuberculosis infection accounts for nearly 15 % of all avian deaths in zoological parks containing mixed species. In most instances, mycobacteria are spread by food and water contamination by feces.

Previously, diagnosis of tuberculosis in living birds has been extremely difficult relying on x-rays, endoscopy, and staining for acid-fast bacteria in the feces, which is not specific. Fortunately, contemporary advancements in DNA diagnostics have produced new and superior techniques that enable accurate and specific pathogenic detection. Recenty, HealthGene Laboratory has taken diagnosis of Mycobacterium to the next level through the introduction of a new PCR based assay that allows for sensitive and timely detection of two strains of mycobacterium most commonly associated with avian tuberculosis (M. genovense and M. avium). HealthGene’s preliminary laboratory results have shown a 3% positive infection rate from initial samples submitted. Furthermore, in some cases, independent government laboratories have confirmed positive results. Tuberculosis screening is also part of HealthGene’s Health Awareness Program aimed at promoting a pathogen-free environment for pet owners. Test requirements are 0.1-0.3 ml of whole blood (EDTA tube) and a fecal sample. Test code: A118 - Avian Tuberculosis.