Concept of an Active Surveillance System for Q Fever in German Small Ruminants-Conflicts Between Best Practices and Feasibility.

Fenja Winter,Benjamin U Bauer,Martin Ganter,Clara Schoneberg,Martin Runge,Silke F Fischer,Ursula Gerdes,Annika Wolf,Amely Campe,T Louise Prüfer

doi:10.3389/fvets.2021.623786

Abstract

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii. Inhalation of contaminated dust particles or aerosols originating from animals (esp. small ruminants) is the main source of human infection. Hence, an active early warning system for Q fever in German small ruminant livestock was conceptualized to prevent human infections. First, we describe the best practice for establishing this system before evaluating its feasibility, as the combination of both evokes conflicts. Vaginal swabs from all husbandry systems with a focus on reproductive females should pooled and investigated by PCR to detect C. burnetii-shedding animals. Multistage risk-based sampling shall be carried out at the flock level and within-flock level. At the flock level, all flocks that are at risk to transmit the pathogen to the public must be sampled. At the within-flock level, all primi- and multiparous females after lambing must be tested in order to increase the probability of identifying a positive herd. Sampling should be performed during the main lambing period and before migration in residential areas. Furthermore, individual animals should be tested before migration or exhibition to ensure a negative status. If a flock tests positive in at least one individual sample, then flock-specific preventive measures should be implemented. This approach implies huge financial costs (sample testing, action/control measures). Hence, taking the step to develop more feasible and affordable preventive measures, e.g., vaccinating small ruminant flocks, should replace testing wherever justifiable.

Highlights

Infectious AgentCoxiella burnetii is a small, obligate intracellular, pleomorphic Gram-negative bacterium
Because of its high tenacity, C. burnetii can be infectious in raw milk for 90–273 days at 4–6◦C as well as in raw milk products like butter and soft cheese for 42 days at 20◦C
Unspecific flu-like symptoms, hepatitis, or atypical pneumonia are possible consequences of acute Q fever, which may led to hospitalization (6, 7)

Summary

Introduction

Infectious AgentCoxiella burnetii is a small, obligate intracellular, pleomorphic Gram-negative bacterium. Because of its high tenacity, C. burnetii can be infectious in raw milk for 90–273 days at 4–6◦C as well as in raw milk products like butter and soft cheese for 42 days at 20◦C. Humans become infected by inhalation of dust particles or aerosols contaminated with only a few C. burnetii organisms (3, 4). Human infections through consumption of raw milk or raw milk products like butter or soft cheese is possible but rare. Infections with C. burnetii remain subclinical in nearly 50% of patients. Approximately 20% of the patients are at risk of developing chronic fatigue after an infection (Q fever fatigue syndrome, QFS) (8). In

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