Transmission of so-called rabbit fever through the food chain is unlikely, according to a risk assessment by a German institute.
Francisella tularensis is a highly virulent bacterial pathogen that causes tularemia, also known as rabbit fever. The Bundesinstitut für Risikobewertung (BfR) said 41 cases were reported in the country in 2016 and 34 in 2015. In Europe, there were between 500 and 1,000 cases annually during 2003-2011.
The reason behind the review by the German institute was a previous, small tularemia outbreak after people ate contaminated food. Infections are mainly due to direct contact with infected animals or with insects like ticks and mosquitos, but contaminated food and water occasionally cause tularemia outbreaks.
The BfR assessed the health risks of Francisella tularensis in foods of plant and animal origin, taking into account resistance of the pathogen during processing of raw food materials. It survives in acidic environments and at low temperatures but is sensitive to heat and pressure.
The BfR said as with other foodborne pathogens, the risk of transmission via foods can be minimized by taking precautionary hygiene measures.
“In the field of food production, this includes avoiding the introduction of fecal contaminants and infected corpses into the production chain and performing decontamination measures during the production process,” said the agency.
“Consumers can protect themselves by following the general rules of kitchen hygiene when handling raw meat and, for example, always cooking meat thoroughly before consumption, in particular in the case of cut meat of hares and wild rabbits.”
The agency added that risk of contracting tularemia primarily affects people with high exposure to infected animals like hunters, people working in forests and gardens, or those who travel to regions where the disease is endemic.
In the United States, naturally occurring infections have been reported from all states except Hawaii. The country reported 230 cases in 2016, the latest year for which data is available.
Symptoms may include sudden fever, chills, headaches, diarrhea, joint pain and a dry cough. Symptoms usually appear three to five days after exposure to the bacteria, but can take as long as 14 days, according to the Centers for Disease Control and Prevention (CDC).
Francisella tularensis is very infectious and a small number of the microscopic organisms, as few as 10, can cause disease.
The ninth international conference on tularemia is scheduled for Oct 16-19 this year in Montreal.
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