Rachel Chalmers has been Director of the national Cryptosporidium Reference Unit (Swansea, Public Health Wales) since January 2000, providing the national reference service including laboratory testing and investigation of outbreaks of cryptosporidiosis. Current research includes detecting and genotyping protozoa in clinical, food, water and environmental samples, assessing public health risks from different sources, investigating the long-term health effects of infection, and developing new methods for detection in food samples. She is an advisor to the WHO in food and waterborne diseases caused by protozoan parasites.
Rachel has co-authored over 150 scientific papers and articles. She led the production of guidance for the investigation of Cryptosporidium cases linked to swimming pools in 2011, and the PWTAG swimming pool survey for Cryptosporidium oocysts in 2017. In 2013 she was made Honorary Professor in Swansea Medical School.