24 cases have been reported in England and Scotland in June and July, of which 21 were associated with travel to Mexico, it said.
Cases have been on the Riviera Maya coast of Mexico, including Cancun, Playa del Carmen and Sian Ka’an, suggesting the source may be a food product distributed to several hotels, said the agency.
PHE recommended patients returning from Mexico with diarrhoea are tested for cyclospora.
PHE on cyclospora
Most cyclospora cases in England and Wales are reported between weeks 23 and 33 (in June and July) so an increase is not unusual.
However, in previous years on average one case per year has been associated with travel to Mexico, so in this regard, the findings are unusual.
Cyclospora cayetanensis is a coccidian protozoan parasite that infects humans and other primates.
There may be substantial under reporting of cyclospora cases, because not all patients are tested and not all positives are reported by laboratories, said PHE.
The organisms are also difficult to spot and recognise in unstained wet films or concentrates.
Foods previously involved include soft fruits such as raspberries and salad products such as coriander, basil and lettuce.
US action and import alert
There is an outbreak of cyclospora in Texas with more than 203 cases, and large outbreaks in Texas in 2013 and 2014 were associated with Mexican salad products.
The Texas Department of State Health Services (DSHS) recommends washing fresh produce, but it may not entirely eliminate risk because Cyclospora can be difficult to wash off. Cooking will kill the parasite.
The US Food and Drug Administration (FDA) has banned some cilantro from Mexico after an investigation found toilet paper and faeces in fields where it is grown.
Shipments of fresh cilantro from April 1 through August 31 can be detained, unless it is from a firm listed on the Green List, according to an import alert.
Multi-ingredient processed foods which have cilantro as an ingredient are not covered and neither is product processed in other ways besides being cut or chopped (e.g., dried).
FDA, the Mexican regulatory authorities for farms, packing houses and processors, Servicio Nacional de Sanidad, Inocuida y Calidad Agroalimentaria (SENASICA) and the Comision Federal para la Proteccion contra Riesgos Sanitarios (COFEPRIS), investigated farms and packing houses in Mexico.
From 2013 to 2015, the agencies inspected 11 farms and packing houses that produce cilantro in the state of Puebla, five of them linked to the US C. cayetanensis illnesses, and found ‘objectionable’ conditions at eight of them, including five linked through traceback to US illnesses.
Findings included human feces and toilet paper found in growing fields and around facilities; inadequately maintained and supplied toilet and hand washing facilities or a complete lack of them; and water used for washing cilantro vulnerable to contamination from sewage/septic systems.
FDA has found firms producing cilantro in Puebla often do business under multiple names, addresses, and registration numbers, and some declare suppliers to be outside of Puebla but have been sourcing cilantro, at least in part, from the state.
Texas focus on 2013 outbreak
Meanwhile, a study has been published looking at 2013 multistate outbreaks of cyclospora with a focus on the investigation in Texas.
The 2013 multistate outbreaks contributed to the largest annual number of reported US cases of
cyclosporiasis since 1997.
Of the 631 cases reported in the multistate outbreaks, Texas reported the greatest number 270 (43%).
More than 70 clusters were identified, four of which were further investigated and Cilantro was found to be the vehicle of infection.
Traceback investigations converged on three suppliers in Puebla, Mexico.
Restaurant-associated illnesses in Iowa and Nebraska during June 2013 were linked to a pre-packaged salad mix from a supplier in Guanajuato.
This means there were at least two US outbreaks of cyclosporiasis associated with different food vehicles from different regions of Mexico during summer 2013.
“The outbreaks of cyclosporiasis in 2013 underscore the need for molecular subtyping to complement evidence from epidemiological investigations, potentially assisting in identifying the number of outbreaks in a given season and suggesting links between clusters, and facilitating source tracking,” said the researchers.
“The specific challenges posed by Cyclospora include under-detection of cases, lack of subtyping methods to link cases to each other or to specific food items, and the absence of practical tools to detect the organism in food and potential sources of contamination in the environment (e.g. soil and insanitary irrigation water).”