Abstract. Quick and cost-effective serologic assays, such as those based on enzyme-linked immunosorbent assay (ELISA) technology, are useful for screening animal populations for infectious diseases. Recombinant protein G is described as an almost universal ELISA conjugate for the detection of antibodies from a wide range of animal species. However, there is limited data documenting the ability of protein G to bind immunoglobulin (Ig) from many captive and free-ranging nondomestic hoofstock (Order Artiodactyla, e.g., elk, antelope, bison). Protein G binding to Ig from 11 species within this taxonomic order (addax, antelope, bison, bontebok, elk, impala, kudu/nyala, muntjac, oryx, sheep, and white-tailed deer) and 2 control species (bovine and chicken) was assessed. A serum Ig enrichment protocol, using high-performance liquid chromatography (HPLC), was optimized in bovids (Bos taurus) and then applied to the other study species. Binding assays were performed by adding protein G to microtiter wells coated with titrated dilutions of enriched artiodactyl Ig. Optical densities were measured and binding curves generated. Differences in protein G binding were observed, both within and among species, as well as within taxonomic families. Significant intraspecies binding variation was observed for 7 species tested (antelope, oryx, sheep, muntjac, impala, bontebok, and addax). No statistically significant intraspecies differences in protein G binding were found for Ig from bison, elk, kudu/nyala, whitetailed deer, plus control species (cattle and chicken). Binding of protein G to Ig from impala, muntjac, and elk was statistically different from the positive control (cattle), with muntjac binding curves statistically comparable with the negative control (chicken). For the other 7 species tested, binding curves illustrated the ability of protein G to bind Ig as well as, or better than, the positive control. These findings expand the list of animal species whose Ig is capable of being detected using recombinant protein G, with the caveat that protein G does not bind Ig uniformly in closely related species. It is concluded that recombinant protein G conjugates may serve as useful reagents for serodiagnosis by ELISA in nondomestic hoofstock, although different assay interpretation algorithms and assay protocols may need to be developed on a per species basis for maximum diagnostic effectiveness.Detection, control, and management of infectious diseases in captive and free-ranging nondomestic ruminant hoofstock species (Order Artiodactyla) often prove challenging. These species, such as okapi, impala, and bontebok, are not often handled, and as a result, samples for diagnostic analysis are infrequently collected. An additional hindrance to disease surveillance is the lack of validated diagnostic assays for these valuable, and in some cases, endangered species.Reliable, cost-effective, and noninvasive diagnostics are needed to maximize the value of diagnostic samples when they can be collected. In particular, for diseases eliciti...

Abstract. An investigation was conducted for Mycobacterium avium ss paratuberculosis infections in a research herd of llamas and alpacas. Herd culture-negative status was established over a 23-month period by screening any individuals with any signs compatible with paratuberculosis (n ϭ 1), high serology values (n ϭ 8), or other health and research related reasons (n ϭ 24). There were no M. avium ss paratuberculosis isolates from radiometric cultures of multiple tissue and fecal samples from these individuals and no known sources of exposure. Paratuberculosis is uncommon in North American llamas and alpacas: only 5 cases were identified after an extensive search of the Veterinary Medical Data Base, diagnostic laboratory records, publication databases, and personal communications. Therefore, serum samples from llamas (n ϭ 84) and alpacas (n ϭ 16) in the culture-negative herd were used to obtain preliminary estimates of test specificity for 3 enzyme-linked immunoassays (ELISAs) and an agar gel immunodiffusion (AGID) assay kit for detecting serum antibodies to M. avium ss paratuberculosis in South American camelids. The ELISAs were modifications of established bovine assays for antibody detection. With provisional cutoffs, ELISA-A had 52 false positives (specificity 48%), ELISA-B had 8 false positives (specificity 92%), ELISA-C had two false positives (specificity 98%), and the AGID had 0 false positives (specificity 100%). The range of ELISA values for culture-positive llamas and alpacas (n ϭ 10) from other herds overlapped the range of values for culture-negative llamas and alpacas. The accuracy of the ELISAs may be improved by using age-and sex-specific cutoffs because uninfected male llamas and alpacas that were older than 1 year had higher values for some tests. These tests can be used for either llamas or alpacas; the protein-G conjugate ELISA (ELISA-B) may be useful for multispecies applications. These assays are best used for rapid presumptive diagnoses of llamas and alpacas with diarrhea and weight loss and as a screening tool for herds known to be exposed to infection. All seropositive results should be confirmed with culture.Recent reports have demonstrated that paratuberculosis is a potential health risk for South American camelids. 2,13 An ongoing outbreak in Australian alpacas (Lama paca) 13 has illustrated that, as in bovine herds, 8 when paratuberculosis is introduced into a previously unexposed herd, much of the herd can become infected prior to any animals showing clinical signs of disease. North American llamas (Lama glama) have been reported with culture-confirmed infections. 2 Because llamas and alpacas constitute a significant industry worldwide and because the value of individual animals can be substantial, paratuberculosis could cause severe economic losses if the disease becomes Received for publication September 29, 1998. established in the industry. Because llama and alpaca importations and animal transfers among herds are important to the genetic and economic health of the llama and a...

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