Occurrence of viral and bacterial pathogens in South American camelids in representative German flocks

Christian Menge^1*Stefanie A Barth¹Eva-Maria Bartl²Christian Berens¹Christa Ewers³Carsten Heydel³Hannah Hümmelchen²Heike Uta Köhler¹Patricia König⁴Alina Leisen²Svenja Mamerow¹Falk Melzer⁵Katja Mertens-Scholz⁵Ulrich Methner⁵Aung Zaw Moe³Dennis Rubbenstroth⁶Christiane Schnee¹Christian Seyboldt⁵Lisa Ulrich²Kerstin Wernike⁶Hermann Willems⁷Henrik W. Wagner²

• ¹Friedrich-Loeffler-Institut, Institute of Molecular Pathogenesis, Jena, Germany
• ²Veterinary Clinic for Reproductive Medicine and Neonatology, Justus Liebig University, Giessen, Germany
• ³Institute of Hygiene and Infectious Diseases of Animals, Justus Liebig University, Giessen, Germany
• ⁴Friedrich-Loeffler-Institut, Institute of Diagnostic Virology, Greifswald-Insel Riems, Germany
• ⁵Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Jena, Germany
• ⁶Friedrich-Loeffler-Institut, Institute of Diagnostic Virology, Greifswald - Insel Riems, Germany
• ⁷Clinic for Swine - Herd Medicine and Molecular Diagnostics, Justus Liebig University, Giessen, Germany

Rapidly growing populations of South American camelids (SAC), introduced to Europe as non-indigenous species, have increased contacts at the livestock and human interfaces. This study assessed the occurrence of epizootic and zoonotic viral and bacterial pathogens of prime importance on ten farms, selected to mirror the diversity of German SAC holdings in size and animal use. Farms were visited four times at approximately six-months intervals, with 20 animals sampled per visit, resulting in 739 blood and 723 fecal samples from 449 animals (292 alpacas, 156 llamas, one huarizo). Wherever possible, diagnostic methods applied followed national or international recommendations. Antibodies against Schmallenberg virus were detected in 54.6% of animals. Only three animals showed reactivity against Borna disease Virus 1 and one against bovine viral diarrhea virus (BVDV) 1. All animals tested negative for BVDV-2, border disease virus and bovine herpesvirus 1. Thirty-six samples from 30 SAC yielded a non-negative, presumably false-positive results for antibodies against the Mycobacterium tuberculosis complex. Ten samples from six animals were non-negative in an iELISA for brucellae antibodies, but all tested negative by Complement Fixation Test. Coxiella burnetii-specific antibodies were detected in three individuals from two different flocks, and a single fecal sample tested PCR-positive for C. burnetii. Chlamydiaceae-specific antibodies were found in 9 of 10 flocks and in 13.6% of the animals, with chlamydial fecal shedding observed in 8 of 10 flocks and in 29.6% of the animals. The animal positivity rate for Candidatus Mycoplasma haemolamae was 31.6%. Mycobacterium avium subsp. paratuberculosis was isolated from 0.34% and C. difficile from 2.7% of the animals. While Salmonella Typhimurium was found in only 1 of 719 fecal samples, thermotolerant Campylobacter (16 C. jejuni and 7 C. coli) were isolated from 4.8% of the animals. The overall rate of stx-positive samples, indicative of Shiga toxin-producing Escherichia coli (STEC) shedding, was 32.4%. Based on these detection rates, SAC do not appear to pose a greater risk of infection than other German livestock species at present. However, SAC represent a novel reservoir host that could disturb established and monitored indigenous epizootic transmission networks including those of enteric and abortifacient zoonotic agents.