A severe outbreak of Streptococcus equi subspecies zooepidemicus (SEZ) has been reported in Italy, linked to the consumption of unpasteurized dairy products. The outbreak was first identified in early 2023, with cases rapidly increasing and spreading across the country. In this article, we delve into the details of this outbreak, exploring the origins of the SEZ bacteria, the impact on affected individuals, and the measures taken to contain and control the spread of the disease. This incident of early release of a highly infectious disease from unpasteurized dairy product consumption highlights the continued importance of food safety and public health measures in the prevention and management of emerging infectious diseases.
A recent early release article reported a large outbreak of the bacterium Streptococcus equi subspecies zooepidemicus in Italy. The bacterium, which can infect domestic animals, pets, and wildlife, sporadically infects humans causing a range of clinical manifestations from meningitis to sepsis. In this outbreak, 18 hospitalized patients in the province of Pescara were infected with S. equi subsp. zooepidemicus from November 2021 to February 2022. The patients had a wide range of clinical manifestations, including septicemia, pharyngitis, arthritis, uveitis, and endocarditis. Five patients died from severe meningitis, and most cases were accompanied by more than one additional localized bacterial site.
The task force, consisting of physicians, veterinarians, epidemiologists, scientists, microbiologists, and communication experts, conducted an active investigation of S. equi subsp. zooepidemicus cases, which identified 37 outbreak cases over a seven-month period. Epidemiologic and laboratory analysis established that consuming unpasteurized fresh cheese produced from infected milk cows was responsible for human infections. The strain isolated from the milk of a cow with mastitis, which belonged to the same operator whose products tested positive, was also identified as ST61 and clustered with other strains isolated from human patients and raw milk products, indicating a zoonotic infection source.
Local authorities established measures to limit and prevent the spread of S. equi subsp. zooepidemicus, including the recall of all dairy products from the market and local dealers, destruction of ripening cheeses, and required pasteurization of milk intended for cheese production. The researchers found strong genomic correlation between strains isolated from case-patients, unpasteurized milk, and dairy products, and milk from infected cows, indicating a zoonotic infection source.
The outbreak in Italy was the largest and most severe outbreak associated with the consumption of unpasteurized fresh cheese reported to date. The study suggests that S. equi subsp. zooepidemicus is a possible zoonotic pathogen with virulence in humans. The One Health interdisciplinary approach used in this study was crucial for managing this outbreak, and further research is needed to gain insights into the bacterium’s pathogenic characteristics responsible for outbreaks. Early diagnosis and identification of bacteria by using molecular methodologies will improve medical treatment outcomes, enable timely epidemiologic disease surveillance, and prevent the spread of life-threatening infections.
As we wrap up our coverage on the severe Streptococcus equi Subspecies zooepidemicus outbreak in Italy, one thing becomes clear: food safety remains a crucial issue that demands our attention. The consumption of unpasteurized dairy products is not only a health hazard, but it also poses a significant threat to public health. While outbreaks like these are not uncommon, they serve as a stark reminder of the importance of proper food handling and regulation. The emergence of infectious diseases is a global health threat, and we must take every step necessary to prevent their spread. We hope that our coverage of this outbreak serves as a wake-up call to all regarding food safety measures and the importance of preventive measures in protecting public health.
