The Dekagram: 18th August 2025

This week we bring news from the gastric coalface; Dr Russell Wilcox examines a recent decision on appeal relating to a sickness claim. The judgment makes for illuminating reading, not least for the exploration of the parties’ expert evidence, and the pivotal role played by the microbiologists’ respective experience in the central issue in the case.

Appeal Dismissed in Diarrhoea Case where Careful Stool Probing  Proved Decisive

In the recent case of Rawson v TUI UK Ltd [2025] EWHC, Mr Justice Cavanagh dealt with an appeal against judgment in a so-called travellers’ diarrhoea case. The legal principles to be applied in such cases are well established, and are summarised in paragraph 6 of Cavanagh J’s judgment, following the well-known authority of Wood v TUI Travel PLC t/a First Choice [2017] EWCA Civ 11; [2018] QB 927. They were not in dispute. What was in dispute, and was explored in great detail, was the expert evidence concerning the pathogenic origin of Ms Rawson’s illness. This involved the court below, and Cavanagh J on appeal, considering the expert evidence of two distinguished microbiologists at a level of granularity which was as illuminating as it was uncommon.

The key facts of the case are set out in short order in paragraph 4 of Cavanagh J’s judgment:

“At about 5 pm on 11 July, the Appellant fell ill with diarrhoea and vomiting.”

This was three days into her holiday. Elsewhere (paragraph 35), she was described as having “explosive diarrhoea”:

“She continued to feel unwell for the rest of the holiday, though she was able to participate in a number of excursions after she had first felt unwell. She suffered bouts of diarrhoea six or seven times a day for the remainder of her holiday.”

The judge goes on:

“After the Appellant’s return, she continued to suffer from diarrhoea, and was diagnosed with gastroenteritis. She has since been diagnosed with Post Infective Irritable Bowel Syndrome and has suffered from anxiety, stress and discomfort as a result. It was the Appellant’s case that this resulted from an infection that was caused by a pathogen in contaminated food or drink that she consumed at the hotel.”

The Appellant’s primary argument was that the cause of her illness was the acquisition of the pathogen cyclospora. Significantly, stool samples were analysed by two separate laboratories back in the UK: a regional Public Health England Laboratory, and the National Parasitology Reference Laboratory. The first concluded that cyclospora oocytes (eggs) were present in the Appellant’s stool; whereas the second, nine days later, found no such indication. The central battle ground in the trial therefore, was whether or not the Appellant had established to the relevant standard that cyclospora had been detected. Cyclospora is found in some locations in Mexico, but rarely, if ever, in the UK, such that a finding on that issue in favour of the Appellant would have put paid to the Respondent’s contention that the Appellant had suffered from illness before she left the UK. It was also significant that cyclospora is (or may be) a food-borne pathogen, and it was conceded by the Respondent that had it been found present it was highly likely that the trial judge would have found in favour of the Appellant (paragraph 13).

The Appellant’s alternative case was that, even if it was concluded that her illness was not caused by cyclospora, the court could be satisfied that “her illness was caused by another pathogen or pathogens that had been consumed in food or drink when staying at the hotel. The Appellant further contended that the food hygiene standards at the hotel were inadequate”.

At trial, HHJ Murdoch sitting in the County Court at Leicester found that the Appellant and her partner “gave straightforward, honest, evidence” (paragraphs 7 and 34). This was not “one of those cases in which a claimant is alleged to have fabricated or exaggerated the symptoms.” (paragraph 7). Notwithstanding that, the judge found that the Appellant’s claim failed, primarily in light of his analysis of the expert microbial evidence, in respect of which he preferred that of the Respondent’s expert Dr Grant, Clinical Director of the Hospital for Tropical Diseases: the institution housing the national reference laboratory.

The Appellant had relied on the expert evidence of Professor Threlfall. Threlfall had given evidence that “testing for cyclospora is notoriously difficult” and that negative results don’t necessarily invalidate positive findings.

“The sample tested by the reference laboratory was reported as normal, no action. It should be realised that testing for cyclospora is notoriously difficult. At the time of the claimant’s illness, the most common method for testing for the presence of cyclospora was concentrate microscopy, where the presence of only a small number of oocytes or even a single oocyte is regarded as indicative of cyclosporiasis [the disease caused by cyclospora]. The test undertaken by the reference laboratory and referred to by the solicitors for the defendant were similarly concentrate microscopy. Thus, a negative result as recorded by the reference laboratory is not necessarily absolutely confirmatory evidence of what has been described as a false positive.” (quoted at paragraph 45).

Professor Threlfall also suggested that the second stool sample, tested by the national reference laboratory, could have deteriorated prior to being tested (paragraph 46), though he later accepted that there were no academic papers to support that theory (paragraph 49). He maintained however that it was “extremely likely that the microbiological cause of the Appellant’s illness was an infection of cyclospora.” (paragraph 44).

In response, Dr Grant testified that regional laboratories lack experience with exotic pathogens, explaining:

“Because laboratory technicians around the UK are not highly experienced in detecting cyclospora, UK public health authorities have designated a national reference laboratory in each country. The National Reference Laboratory for England is the Hospital for Tropical Diseases, where staff have specific experience and training in identifying the organism. The stool sample provided by the claimant was, on the balance of probabilities, one of those false positives; the local lab thought they had seen it but the more experienced lab did not identify cyclospora.” (quoted at paragraph 47.)

In cross-examination, Professor Threlfall conceded that testing at the national reference laboratory was the gold standard, and that he would defer to Dr Grant’s testing experience (paragraph 30).

A particular point relied upon on appeal, was when, during cross-examination, and after extensive questioning on Public Health England protocols, Dr Grant appeared to concede that the case might be described as probable cyclospora infection:

“So it’s epidemiological, it’s to do with pragmatism, limited resources, and it allows for definition to be put in place, and it’s probable and you’re right that’s how it is. So for the court that is what the particular specimen or this particular case might be described as.” (quoted in paragraph 50)

Re-examination, however, allowed Dr Grant to clarify that remark by emphasizing that what he was saying was that on the papers there was a probable finding of cyclospora oocytes, but not once a full examination of all the features of the case were taken into account (paragraph 51).

HHJ Murdoch gave a number of reasons for preferring Dr Grant’s evidence, these included: his superior expertise in cyclospora testing, the national reference laboratory’s specific role in verifying regional findings, and his more cogent technical explanations regarding antibody presence and oocyte degradation theories (paragraph 54). HHJ Murdoch concluded 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.” (paragraph 55).

HHJ Murdoch also rejected the Appellant’s secondary argument which was advanced on the basis that she had consumed nothing outside of the hotel before developing symptoms, such that any pathogen must have come from hotel sources. As anyone familiar with these types of claims will be aware, such arguments are particularly challenging in the absence of evidence of contemporaneous “outbreaks”, showing that other guests suffered similar symptoms. In this case, such evidence was lacking (paragraphs 57-64). At paragraph 80, it is observed:

“The judge regarded a more important issue to be that there was no evidence of a more generalised outbreak of food poisoning at the time of the Appellant’s illness, as the judge would have expected there to be, if her illness had been caused by food poisoning. The judge accepted Mr Pennock’s point that the Respondent’s records cannot be complete, because they can only record complaints that are made to the Respondent’s representatives on site, and that the hotel records can only record complaints made to them… Nonetheless, these factors were always present and yet there were records in other months of illness at the hotel, but not such records for the period when the Appellant was at the hotel. There had been complaints of illness to the Respondent’s representatives at the hotel in the period from 1-8 July (this was a typo, in fact the period was 1-8 June), and then again from 8 August onwards, with a peak on 17 August, when six guests complained of gastric illness. The hotel’s doctor did not record any complaints of gastric illness between 14 June and 8 August and then there two peaks later in August which reflected the Respondent’s record.”

HHJ Murdoch ultimately resolved the causation issue on burden of proof principles, stating:

“…it is not for the defendant to prove what the source was, it is for the claimant to prove that it is the food and the drink, something that she has consumed, and in my judgment… the claimant has failed to do so.”

The Appellant sought to raise thirteen grounds of appeal. These included contentions that the trial judge misunderstood the laboratory evidence, failed to understand or place proper weight on Dr Gant’s supposed concession in cross-examination, and failed to consider evidence supporting the contention that there had been food poisoning at the hotel (paragraph 86 ff).

None of these grounds, however, found favour with Mr Justice Cavanagh. Reiterating the well-established jurisprudence governing when an appeal court should interfere with findings of fact at first instance, he placed reliance, in particular, on the dicta of  Coulson LJ in Wheeldon Bros Waste Ltd v Millennium Insurance Co Ltd [2018] EWCA Civ 2403; [2019] 4 WLR 56. He found both that there were “ample grounds for the judge’s conclusion that the Appellant’s illness was not caused by the cyclospora pathogen” (paragraph 120) and that the trial judge did “not misunderstand the evidence” (paragraph120).To the contrary, he described HHJ Murdoch’s determination as “a careful and impressive judgment which addressed all of the main issues in the case..”. (paragraph 140)

“The irreducible fact” Cavanagh J concluded, “is that the judge accepted the expert evidence of the Respondent’s key witness and preferred it over the evidence of the Appellant’s key expert witness.” (paragraph 140) In consequence, it being a rolled up hearing in which he had, in substance undertaken a full review of the evidence, whilst he granted permission to appeal, he nonetheless dismissed that appeal.

About the Author

Dr Russell Wilcox was called to the Bar in 2000, and before joining chambers enjoyed an illustrious career in academia. He was an associate member of McNair Chambers in Qatar, where he worked on a number of large-scale cross-jurisdictional commercial disputes and on international arbitral proceedings, and acted as disclosure counsel in Athenasios Sophocleus & Others v Secretaries of State for Foreign and Commonwealth Affairs and Defence, relating to the actions of the Colonial Administration in Cyprus during the Cyprus Emergency of 1956 to 1959. He now accepts the full range of work undertaken by the travel team at Deka Chambers.