Objective: Cryptosporidiosis is a gastrointestinal illness spread via infected people, animals, or contaminated water or food. This article describes a cryptosporidiosis outbreak associated with a swimming pool in Melbourne, Australia in February 2025. Methods: On 13 February, the North Eastern Public Health Unit was simultaneously notified of a complaint of gastroenteritis symptoms by a social group who swam at Pool A on 4 February and of gastroenteritis symptoms among students at School B who attended the same pool on 5 February. An outbreak was declared and an investigation commenced. Communications were sent to 1034 pool patrons and schools that attended the pool in early February to advise of the outbreak, provide safe swimming messages and encourage testing among symptomatic individuals. Interviews with symptomatic individuals were undertaken. An online questionnaire supported active case finding and information-sharing. Local clinicians and laboratories were alerted to the outbreak and healthy swimming messages were promoted at the pool. Results: Cryptosporidiosis was suspected due to the 4–9-day incubation period. Due to initial reports of a high attack rate among the students and concerns about ongoing exposure to current pool users, the pool was immediately closed for hyperchlorination. Subsequent urgent faecal specimen testing confirmed Cryptosporidium. Overall, 16 confirmed and 59 probable cases were identified. The most common symptoms were diarrhoea (56%), abdominal pain (48%) and nausea (45%). Of those who only attended the pool once, the median incubation period was 7 days (range: 4–9 days). No cases were identified after hyperchlorination. Discussion: This pool-associated cryptosporidiosis outbreak demonstrates the importance of rapid outbreak investigation and response, and pre-emptive aquatic environmental control measures to prevent ongoing transmission.

AIMTo produce biologically active recombinant human (rh) ZP proteins in a human cell for use in sperm function tests.

METHODSThe human embryonic kidney cell line 293T was employed to produce rhZP1, rhZP2 and rhZP3 proteins individually and together by co-expression. Presence of these proteins in the culture medium and cell lysate was assessed by Western blotting analysis. The effect of the recombinant proteins on the human AR was assessed.

RESULTSRhZP2 and rhZP3 were secreted into the culture medium, whereas rhZP1 was found only in the cell lysate. Interestingly, when all zona pellucida proteins were co-expressed in the same cells, rhZP1 was also secreted into the culture medium. However, despite the presence of all three ZP proteins in sufficient concentration and evidence of heavy glycosylation on gel electrophoresis, biological activity to induce the AR was not observed.

CONCLUSIONRhZP1, rhZP2 and rhZP3 were successfully expressed in the human embryonic kidney cell line 293T. It appears that an interaction amongst these proteins may be required for release of rhZP1 from the cell. Although this approach is not satisfactory for producing active human ZP proteins, it makes a significant contribution to the understanding of the structural and functional characteristics of the ZP proteins.

Acrosome Reaction ; drug effects ; Blotting, Western ; Cell Line ; Egg Proteins ; analysis ; genetics ; pharmacology ; Embryo, Mammalian ; Female ; Fluorescent Antibody Technique ; Gene Expression ; Glycoside Hydrolases ; metabolism ; Glycosylation ; Humans ; Kidney ; Male ; Membrane Glycoproteins ; analysis ; genetics ; pharmacology ; Receptors, Cell Surface ; analysis ; genetics ; Recombinant Proteins ; analysis ; pharmacology ; Zona Pellucida Glycoproteins