Serum antigen 85 levels in adjunct testing for active mycobacterial infections in orangutans

A. M. Kilbourn, H. P. Godfrey, R. A. Cook, P. P. Calle, E. J. Bosi, S. I. Bentley-Hibbert, K. Huygen, M. Andau, Michael H Ziccardi, W. B. Karesh

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Diagnosis of active mycobacterial disease in orangutans (Pongo pygmaeus) has been impeded by high levels of non-specific intradermal skin test reactivity to mycobacterial antigens. This may be due in part to cross reactivity between antigens, tuberculin concentrations used or other species-specific factors. Antigen 85 (Ag85) complex proteins are major secretory products of actively growing mycobacteria, and measurement of serum Ag85 could provide a method for determining active mycobacterial infections that was not dependent on host immunity. Serum Ag85 was measured by dot-immunobinding assay using monoclonal anti-Ag85, purified Ag85 standard and enhanced chemiluminescence technology in coded serum samples from 14 captive orangutans from a zoo in Colorado, 15 semi-captive orangutans in Malaysia, and 19 free-ranging wild orangutans in Malaysia. Orangutans from Colorado (USA) were culture negative for Mycobacterium tuberculosis and M. avium, although all had laboratory suspicion or evidence of mycobacterial infection; median serum Ag85 was 10 μU/ml (range, <0.25-630 (μU/ml). Of the semi-captive orangutans, six were skin test reactive and two were culture positive for M. avium on necropsy. Median serum Ag85 for this group was 1,880 μU/ml (0.75-7,000 μU/ml), significantly higher than that of Colorado zoo or free-ranging Malaysian orangutans. Median serum Ag85 in the latter group was 125 μU/ml (range, 0.75-2,500 μU/ml). These data suggest that suggest that additional studies using more specific reagents and more samples from animals of known status are appropriate.

Original languageEnglish (US)
Pages (from-to)65-71
Number of pages7
JournalJournal of Wildlife Diseases
Issue number1
StatePublished - Jan 2001
Externally publishedYes


  • Antigen 85
  • Diagnosis orangutan
  • Mycobacterium tuberculosis
  • Pongo pygmaeus

ASJC Scopus subject areas

  • veterinary(all)


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