1. PHLS Cryptosporidium Reference Unit, Swansea Public Health Laboratory, Singleton Hospital, Swansea, United Kingdom SA2 8QA1;
2. North Wales Health Authority, Preswylfa, Mold, United Kingdom CH7 1PZ2; and
3. Rhyl Public Health Laboratory, Glan Clwyd District General Hospital, Rhyl, Denbighshire, United Kingdom LL18 5UJ3