Peñuelas, MarinaCarmena, DavidGuzmán Herrador, Bernardo RPalau Miguel, MargaritaSaravia Campelli, GabrielaGarcía Álvarez, Rosa MaríaGuerrero-Vadillo, MaríaDashti, AlejandroKöster, Pamela CarolinaGuevara Alemany, EsperanzaSimón Soria, FernandoFuentes Corripio, IsabelVarela Martinez, Maria del CarmenSierra Moros, María JoséWorking group for the National Surveillance Network2024-10-112024-10-112024-07Euro Surveill. 2024 Jul;29(28):2300733.1025-496Xhttps://hdl.handle.net/20.500.12105/25086Background: By mid-September 2023, several event notifications related to cryptosporidiosis had been identified from different regions in Spain. Therefore, a request for urgent notification of cryptosporidiosis cases to the National Surveillance Network was launched. Aim: We aimed at assessing the extent of the increase in cases, the epidemiological characteristics and the transmission modes and compared to previous years. Methods: We analysed data on case notifications, outbreak reports and genotypes focusing on June-October 2023 and compared the results to 2016-2022. Results: In 2023, 4,061 cryptosporidiosis cases were notified in Spain, which is an increase compared to 2016-2022. The cumulative incidence was 8.3 cases per 100,000 inhabitants in 2023, sixfold higher than the median of 1.4 cases per 100,000 inhabitants 2016-2022. Almost 80% of the cases were notified between June and October. The largest outbreaks were related to contaminated drinking water or swimming pools. was the most common species in the characterised samples (115/122), and the IfA12G1R5 subtype, previously unusual in Spain, was detected from 76 (62.3%) of the 122 characterised samples. Conclusions: A substantial increase in cryptosporidiosis cases was observed in 2023. Strengthening surveillance of is essential for prevention of cases, to better understand trends and subtypes circulating and the impact of adverse meteorological events.engVoRhttp://creativecommons.org/licenses/by/4.0/CryptosporidiumSpainIncreaseOutbreakSurveillanceWaterborne infectionAdolescentAdultChildChild, PreschoolCryptosporidiosisCryptosporidiumDisease NotificationDisease OutbreaksDrinking WaterFecesFemaleGenotypeHumansIncidenceInfantInfant, NewbornMaleMiddle AgedPopulation SurveillanceSpainSwimming PoolsYoung AdultAttribution 4.0 International389946032928230073310.2807/1560-7917.ES.2024.29.28.23007331560-7917Euro surveillance : bulletin Européen sur les maladies transmissibles = European communicable disease bulletinopen access