Review and analysis of knowledge, tools, and implementation gaps for the control of cryptosporidiosis in livestock

Cryptosporidiosis, the disease caused by infection with Cryptosporidium spp., is an important threat to both human and veterinary health; some Cryptosporidium species, particularly Cryptosporidium parvum , being zoonotic. The most usual manifestation of cryptosporidiosis is acute diarrhoeal disease, but respiratory disease due to Cryptosporidium baileyi infection can also occur in poultry. In other livestock, particularly young ruminants in which C. parvum is the most clinically relevant species, this can have an important impact. Although the mortality rate is generally low, morbidity can be considerable and can result in significant economic losses due to veterinary costs and reduced productivity. Considerable efforts have therefore been directed towards developing tools for combating cryptosporidiosis in livestock. Although diagnostic tools have improved in the past decades, treatments and prevention have not advanced at a commensurate pace. The two mainly available pharmaceutical treatments for livestock are shown to have some effect on reducing diarrhoea and oocyst shedding, but have limited therapeutic windows and restrictions on use. A recently introduced vaccine provides protection to calves by raising antibodies against C. parvum in pregnant cows, which are transferred to their calves via colostrum. It is only for use in cattle and not available globally. With both the available pharmaceutical treatments and the vaccine, oocyst shedding is not eliminated, thus environmental contamination remains a source of infection for animals and people. This means that on-farm operations, including biosecurity measures and management of slurry and manure, should be used in combination with pharmaceutical treatment and vaccination. However, the efficacy of such measures needs further investigation. This review is based on the recently updated DISCONTOOLS analysis, which identifies knowledge gaps and advances the development and implementation of new tools for controlling cryptosporidiosis in livestock. While vaccination and treatment have important roles, appropriate farm management, especially good farm hygiene, as well as handling and treatment of manure, remains a vital component for reducing the risk of cryptosporidiosis.