In 2006 five Asian Elephants were imported to Taronga Zoo, Australia, from Thailand. Pre-import tuberculosis screening and initial post-arrival screening was by trunk wash (TW). In April 2009 the Elephant TB Stat-Pak® (SP, Chembio) was used to screen the elephants. A 15.5-year-old pregnant cow was reactive. TW frequency for this cow was increased to every three months. TW culture and PCR remained negative on all elephants. In February 2010 this cow reacted on the Dual Path Platform Vet®TB test™ (DPP, Chembio). All other elephants were non-reactive. With concern about the effect of anti-tuberculous drugs on her foetus and ongoing negative TWs, screening continued every three months and treatment was not initiated.
The cow gave birth on November 2, 2010. A routine TW on November 24, 2010, was culture positive for M. tuberculosis. Although previous shedding could not be ruled out, reactivation of latent infection due to parturition was suspected. Enhanced infection control, repeat staff screening, and staff education sessions were implemented.
Treatment with isoniazid, pyrazinamide, rifampicin, and ethambutol commenced. The isolate was susceptible to these drugs and genotyped as a Beijing strain. Retrospective serum from Thailand (2004) and Australia (2006) were positive on SP and DPP.
TW, SP, and DPP screening frequency increased to monthly for the positive cow. Monthly serum chemistry indicated drug-induced hepatitis. Drug pharmacokinetics were conducted to ensure therapeutic levels were achieved. TW and blood-collection training of the infant calf was initiated. For all other elephants, TW and SP screening increased to every three months.
We thank the Taronga elephant team, hospital staff, Michele Miller, Susan Mikota, Konstantin Lyashchenko, and the many others who were involved and provided assistance.