KA-2024-BHM-000008 - [2025] EWHC 2093 (KB)

The judge’s conclusions on the cyclospora issue

The judge preferred Dr Bowling’s evidence to that of Professor Bjarnason, because the judge took the view that Professor Bjarnason had a tendency to express views on matters that were outside his area of expertise. The judge accepted Dr Bowling’s view that, if the Appellant had a cyclospora infection, she was and remained symptomatic. However, the gastroenterologists deferred to the microbiologists on the cyclospora issue, and so the views of the gastroenterologists did not determine the cyclospora issue (or the causation issue).

The judge preferred the evidence of Dr Gant to that of Professor Threlfall. He observed that Professor Threlfall accepted that Dr Gant has greater experience for testing for cyclospora oocytes. Dr Gant’s laboratory (the national reference laboratory) has the expertise and Professor Threlfall’s does not. Dr Gant’s evidence on the testing process was more cogent. He was right, and Professor Threlfall, was wrong, when Dr Gant said that there was no antibody for the oocytes and that they fluoresced naturally, and Professor Threlfall said that there was an antibody, and also when Dr Grant said that the oocytes did not deteriorate rapidly over time, and Professor Threlfall said that they did. Professor Threlfall’s suggested explanation for the different results, that the oocytes had disappeared from the stool sample between tests, was therefore not accepted. Both microbiology experts made clear that the identification of cyclospora oocytes was not easy, and they could readily be confused with other pathogens, such as yeast. The purpose of the national reference laboratory was to check that the initial findings of the regional laboratory were correct, and they had done their job and had concluded that they were not correct.

The judge said that he would have required extremely cogent evidence to persuade him that the national reference laboratory had got it wrong, and there was no such evidence.

For these reasons, the judge found on the balance on probabilities that the Appellant did not have cyclospora in her stool sample and so there was no direct evidence of the presence of cyclospora. The judge concluded that the Appellant’s symptoms were caused by another pathogen.