Cryptosporidiosis infections spike during summer swim season



Outbreaks of cryptosporidiosis increased in the United States by an average of 13% each year between 2009 and 2017, based on data from the Centers for Disease Control and Prevention.

In a study published in the CDC’s Morbidity and Mortality Weekly Report, researchers reviewed data from 444 reported outbreaks submitted to the CDC’s National Outbreak Reporting System totaling 7,465 cases, including 287 hospitalizations and one death.

The outbreaks during this period were most commonly associated with pools and water parks (35%), exposure to cattle (15%), and child care settings (13%). Another 3% of outbreaks were associated with drinking unpasteurized milk or apple cider. An outbreak was defined as two or more cases linked to a common source.

The profuse, watery diarrhea associated with infection from the cryptosporidium parasite can last for 3 weeks in healthy individuals and can cause life-threatening malnutrition in the immunocompromised, wrote Radhika Gharpure, DVM, of the CDC’s National Center for Emerging and Zoonotic Infectious Diseases, and colleagues.

The overall number of outbreaks peaked during July and August each year; the number associated with pools and water parks peaked between June and August, the number associated with cattle peaked between March and May, and the number associated with child care settings peaked between July and September.

The results were limited by several factors including likely underestimation of the number of outbreaks, the use of multipathogen testing panels that could have inflated the number of outbreaks, and the variation in the ability of jurisdictions to detect, investigate, and report outbreaks, the researchers noted. CryptoNet, a molecularly-based surveillance system, has shown potential to track disease transmission, they said.

However, primary prevention is important to prevent the spread of disease, and strategies include refraining from swimming when one has diarrhea and for 2 weeks after resolution of diarrhea, not sending children to child care when they have diarrhea, and washing hands thoroughly after contact with animals, the researchers said.

“If a cryptosporidiosis outbreak occurs, substantial decontamination measures are needed, including hyperchlorinating public treated recreational water venues (e.g., swimming pools at a hotel, apartment complex, or water park) and using hydrogen peroxide to disinfect surfaces in child care settings to inactivate Cryptosporidium oocysts,” they emphasized.

The researchers had no financial conflicts to disclose.

SOURCE: Gharpure R et al. MMWR. 2019 June 28. 68:568-72.

Next Article: