Abstract

An investigation into the health of the in situ population of Guam rail was initiated to determine the prevalence of disease issues that could impact the in situ captive and release populations as well as zoological populations. This type of investigation had not been conducted on the in situ population since the repatriation program started in the 1990s. This investigation included a review of pathology records, analysis of the in situ captive diet, and clinical examination of two release populations (n=100) as well as the captive breeding population (n=50). In addition, clinical sampling of local domestic chicken (Gallus gallus) populations (n=50) was performed to determine prevalence of diseases of concern to the rail population. Free-ranging chickens are common on the islands of Guam and Rota where rails are being released.

Mortality records for the in situ captive breeding population from 1994–2003 were reviewed to determine prevalence of disease in the historic population. The in situ captive population diet was collected frozen for nutritional analysis. Diagnostic testing for the rails included complete blood count (CBC), plasma chemistry analysis, plasma protein electrophoresis, Mycobacterium avium complex (MAC) serology, arboviral serology (Eastern equine encephalitis, St. Louis encephalitis, Japanese encephalitis, and West Nile virus), enteric pathogen culture, fecal MAC antigen detection via polymerase chain reaction (PCR), and fecal acid-fast cultures. Diagnostic testing for the domestic chickens included serum arboviral serology (Eastern equine encephalitis, St. Louis encephalitis, Japanese encephalitis, and West Nile virus), enteric pathogen culture, and fecal acid-fast cultures. Findings from the health assessment were reviewed to identify significant pathologic findings; significant disease noted on physical examination, CBC, plasma chemistries, and plasma protein electrophoreses; prevalence of arboviral antibody; prevalence of fecal acid-fast bacteria; and prevalence of enteric pathogens such as Salmonella and Campylobacter.