Case definition:
- a person with diarrhoea and the identification of Cyclospora cayetanensis oocysts in a stool sample (Multiple specimens may be required as cases may not shed sufficient oocysts in stools)
Cause:Cyclospora cayetanensis, a protozoan parasite
Reservoir: Humans
Epidemiology:
- cases are usually associated with travel to Central or South America, the Caribbean islands, Indian subcontinents and South East Asia
- infection occurs worldwide however the parasite is not endemic in the UK. Since 2015, large outbreaks have been reported in the UK from travellers returning from Mexico
Transmission:
- direct person-to-person spread is unlikely
- cyclospora cayetanensis is transmitted by ingesting infective oocysts. Oocysts are excreted in faeces of human hosts in a non-infective form. They must then sporulate (mature) over 7-15 days in the environment to become infective
- ingestion of sporulated oocysts from sources such as drinking water, and fresh foods cause infection
- outbreaks linked to imported fresh berries, herbs and salad leaves have been documented in developed countries
Incubation period: Usually 7 days (range 1-14 days)
Clinical presentation:
- watery diarrhoea which may be prolonged
- other symptoms often include abdominal pain, fatigue, nausea, flatulence, weight loss and loss of appetite. Vomiting, headache and fever may also occur
- some cases may be asymptomatic
Infectivity: Direct person-to-person spread is unlikely
Notes (1):
- immunocompromised cases may remain infected for several months, but treatment will clear infection
- in a cluster/outbreak situation, a travel history should be sought and if none, a detailed food history (including raw fruits, salads, herbs and imported foods) should be undertaken
Reference:
- PHE (2019). Recommendations for the Public Health Management of Gastrointestinal Infections