Covid-19 control measures alter transmission patterns of Cryptosporidium hominis in New Zealand

Covid-19 nonpharmaceutical interventions have been effective control measures for a range of respiratory illnesses throughout the world. These measures, which include isolation, strict border controls, social distancing and improved hygiene also have effects on other human pathogens, including parasitic diseases of the gut such as cryptosporidiosis.

Cryptosporidium infections in humans are mostly caused by two species: C. hominis, which is primarily transmitted from human-to-human, and C. parvum, which is mainly derived from animals, particularly livestock. New Zealand's initial Covid-19 control measures began in March 2020, with a nationwide lockdown period of more than 7 weeks. By monitoring Cryptosporidium species and subtype families in human cases of cryptosporidiosis before and after the introduction of Covid-19 control measures, IDReC researchers have found C. hominis infections were completely absent after the first months of 2020 and remained so until the beginning of 2021. Meanwhile, C. parvum followed its typical transmission pattern and continued to be widely reported.

These results suggest that isolation during the initial lockdown period interrupted human-to-human transmission of cryptosporidiosis caused by C. hominis, leaving only the primarily zoonotic transmission pathway used by C. parvum. We are looking forward to reporting our ongoing monitoring of Cryptosporidium species and subtypes, particularly as border restrictions ease.


Access to the full article, recently published in Parasitology can be found here


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