title: Characterization and management of asymptomatic Mycobacterium infections at the Zebrafish International Resource Center.
abstract: The Zebrafish International Resource Center (ZIRC) supplies wildtype, mutant, and transgenic zebrafish (Danio rerio) to the international research community. In 2005, the ZIRC halted shipment of adult Tübingen (TU) zebrafish, a popular wildtype line, after diagnosis of asymptomatic  Mycobacterium chelonae infections in a high proportion of the TU stock. Mycobacterium presents a zoonotic risk to fish handlers. In addition, the presence of underlying chronic disease in a model organism is unacceptable. The TU stock was depopulated and replaced by a new import  of TU with the intent of reducing disease prevalence. In the current study, we sampled the new population of TU and fish of the AB, Tupfel long-fin (TL), TAB5 and TAB14 (2 AB × TU hybrid lines), and wildtype-in-Kalkutta (WIK) lines for histologic evaluation and acid-fast staining and  compared the prevalence of subclinical mycobacteriosis between these lines. Although prevalence in the new TU stock was lower than that of the original TU stock, asymptomatic infections with Mycobacterium remained high (10%) in the new TU stock held in 20-gal tanks. The prevalence was similar  (10%) in the TAB5 line compared with other wildtype lines held in similar conditions. Prevalence of infections in TU can be minimized by husbandry adjustments, including tank size, population density, and cleaning method. Application of these findings has allowed us to decrease mycobacteriosis  in TU zebrafish and resume shipment of TU adults to the research community.
authors.affiliation: Zebrafish International Resource Center, University of Oregon, Eugene, OR, USA. katy@zebrafish.org
authors.forename: Katrina N
authors.initials: KN
authors.lastname: Murray
authors.forename: Justin
authors.initials: J
authors.lastname: Bauer
authors.forename: Ari
authors.initials: A
authors.lastname: Tallen
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Matthews
authors.forename: Monte
authors.initials: M
authors.lastname: Westerfield
authors.forename: Zoltan M
authors.initials: ZM
authors.lastname: Varga
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D000830:Animals, Laboratory; D058070:Asymptomatic Diseases / Q000453:epidemiology*; D005393:Fish Diseases / Q000453:epidemiology* / Q000382:microbiology*; D007756:Laboratory Animal Science / Q000379:methods; D009164:Mycobacterium Infections / Q000453:epidemiology / Q000662:veterinary*; D016926:Mycobacterium chelonae; D015995:Prevalence; D012499:Sanitation / Q000379:methods; D013045:Species Specificity; D015027:Zebrafish