Bleach preserves viability
One in ten deaths of children under 5 years old globally is due to diarrheal disease and this disproportionally affects children in developing countries. A study funded through the Bill and Melinda Gates Foundation (Kotloff et al., 2013) showed that the pathogen Cryptosporidium parvum was the second most prevalent cause of diarrheal disease and a significant source of childhood mortality. Research into Cryptosporidium therapies was identified as a key priority to reduce the worldwide burden of diarrheal disease.
A significant roadblock in the development of a therapy is the lack of a cryopreservation strategy for Cryptosporidium. Instead, the parasite must be maintained through constant propagation in calves, mice, and pigs. However, a recent study in Nature Communications (Jaskiewicz et al., 2018) made a significant advance by developing a protocol enabling cryopreservation of viable, infectious oocysts-- something which had been unsuccessfully attempted for the past 30 years.
The researchers made two important findings to develop this protocol. First, oocysts have a thick outer wall that must be permeabilized with bleach before CPAs are added. Second, once the inner sporozoites were dehydrated they could be frozen via ultrafast cooling (only slow freezing had been attempted previously). Importantly, after thawing the cryopreserved oocysts, they were able to establish infections in a mouse model, bringing researchers one step closer to an effective therapeutic agent. -Dr. Kate Franz