Most common diagnoses and antibiotics used in South American Camelid patients at a university clinic in Austria

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TL;DR

This retrospective study of 634 South American Camelid patients at a university clinic in Austria (2005–2019) found that digestive tract disorders and castrations were the most common reasons for antibiotic use, with cefquinome (EMA Category B) being the most frequently applied substance. Over time, the proportion of EMA Category D (first-line) antibiotics increased to over 50% of annual use by 2017, but Category B use did not decrease, likely due to complex cases. The findings highlight the need for antimicrobial stewardship and further pharmacokinetic research in these minor species.

Full summary

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**Background:** The popularity of South American Camelids (SACs) in Europe is rising, with an estimated 10,000 llamas and alpacas in Austria. Despite their increasing numbers, evidence-based data on common diseases and antibiotic use in SACs is limited. In the EU, SACs are classified as farmed game, and no antibiotics are approved for them, requiring off-label use under food-producing animal rules. The European Medicines Agency (EMA) categorizes antibiotics from A (avoid) to D (prudence) to guide prudent use and reduce antimicrobial resistance (AMR). This study aimed to retrospectively evaluate which diseases led to antibiotic treatment in SACs at the University Clinic for Ruminants (UCR) in Vienna, Austria, from 2005 to 2019, and to assess the most frequently used antibiotic substances.

**Methods:** All SAC patient records from January 1, 2005, to December 31, 2019, were extracted from the animal hospital information system (AHIS). Only animals with diagnoses related to antibiotic treatment were included. Diagnoses were classified using the Health Monitoring (GMON) coding system, with additional categories for SAC-specific diseases. Antibiotic substances were categorized per EMA classification (A–D). Data analysis was performed using R (dplyr, ggplot2, reshape2). The term 'application' refers to an individual dose; 'treatment course' refers to a series of applications for a single disease episode.

**Key Results:** A total of 634 SAC patients were treated at the UCR over 15 years. Of these, 204 medical cases in 202 alpacas and 139 cases in 136 llamas received antibiotics. Five animals were treated twice. The number of alpaca patients requiring antibiotics increased from 0 in 2005 to 33 in 2019. The most frequent indications for antibiotic use were digestive tract disorders (82 treatment courses) and castrations (79 treatment courses). By number of applications (N=1,466), the most commonly used substances were cefquinome (347 applications, 23.7%), benzylpenicillin/streptomycin (286, 19.5%), amoxicillin/clavulanic acid (251, 17.1%), and ampicillin (205, 14.0%). Cefquinome (EMA Category B) was most frequently used for digestive tract diseases and cria diseases. From 2017 onwards, EMA Category D antibiotics made up more than 50% of annual antibiotic use in milligrams. Category B antibiotics ranged from 0% in 2005–2006 to a maximum of 11.1% in 2015. The majority of applications were intramuscular (69.3%), followed by subcutaneous (14.0%).

**Clinical Implications:** This study provides a comprehensive overview of antibiotic use in SACs over 15 years, highlighting that digestive tract disorders (especially dental disease and suspected Clostridium perfringens enterotoxemia) and castrations are the most common reasons for antibiotic therapy. The increasing use of EMA Category D antibiotics over time suggests a shift toward more prudent prescribing, but the persistent use of Category B antibiotics (e.g., cefquinome) in complex cases (e.g., crias with high mortality, severe dental disease) underscores the challenge of balancing clinical need with antimicrobial stewardship. The authors emphasize the importance of bacteriological culture and sensitivity testing, especially when using Category B antibiotics, and the need for further pharmacokinetic and clinical trials in SACs to optimize treatment protocols. The findings are relevant to One Health, as reducing Category B antibiotic use in animals is critical to preserving their efficacy in human medicine.