Resumen de Occurrence of Cryptosporidium oocysts and Giardia cysts in water from irrigation channels in Catalonia (NE Spain)

Mercedes Gracenea Zugarramurdi, M. S. Gómez López, C. M. Ramírez

• español

  Se aportan los primeros datos conocidos en España referentes a la detección de ooquistes de Cryptosporidium spp. y quistes de Giardia spp. en canales de riego cuya agua es utilizada tanto para fines agrícolas como de consumo humano. Se tomaron muestras de 10 l en 11 puntos de muestreo de 3 canales y los quistes de Giardia por tinción con mertiolato-yodo-formol (MIF). Cryptosporidium estuvo presente en los tres canales prospectados y Giardia en dos, Urgell y Aragón-Cataluña. La prevalencia fue de 18,4% (10/54) para Cryptosporidium y de 15,6% (5/32) para Giardia. Las muestras positivas para Cryptosporidium fueron más frecuentes en invierno (22,2%; 4/18) que en primavera-verano (20%; 3/15) y otoño (14,3%;

  3/21). La positividad de Giardia fue muy similar: primavera-verano (20%; 2/10), otoño (18,1%; 2/11) e invierno (9%; 1/11). La concentración de Cryptosporidium osciló entre 3 y 82 ooquistes/l y la de Giardia entre 2 y 5 quistes/l. El tratamiento del agua basado únicamente en la cloración para desinfección no inactiva los ooquistes de Cryptosporidium ni los quistes de Giardia, resultando un riesgo para los consumidores de riego, Pinyana, Aragón-Cataluña y Urgell. Las muestras se procesaron por concentración y separación inmunomagnética, identificándose los ooquistes de Cryptosporidium mediante la tinción de Ziehl-Neelsen

• English

  Data regarding the detection of Cryptosporidium oocysts and Giardia cysts in the irrigation channels which water is used for both agricultural purposes and for drinking water, are reported for the first time in Spain. Samples of 10 litres were taken at 11 sample sites of 3 irrigation channels, Pinyana, Aragón-Cataluña and Urgell. Water samples were processed by concentration and immunomagnetic separation. Oocysts were identified by using the Ziehl-Neelsen staining modified technique and cysts were stained with merthiolatiodine- formol (MIF). Cryptosporidium oocysts were detected in all three channels prospected. Giardia cysts were present only in two, the Urgell and Aragón-Cataluña channels. Prevalence in the total samples analyzed was 18.4% (10/54) for Cryptosporidium and 15.6% (5/32) for Giardia. The positive samples of Cryptosporidium were more frequent in winter (22.2%, 4/18) than in spring-summer (20%; 3/15) and autumn (14.3%; 3/21). Giardia positive samples were similar in spring-summer (20%; 2/10), autumn (18.1%; 2/11) and in winter (9%; 1/11). The more frequent oocyst concentration was around 7 oocysts/l (3-82 oocysts/l). The concentration of Giardia cysts was lower, in a range of 2-5cysts/l. Treatment relying only on chlorination for disinfection of water will not effectively neutralize Cryptosporidium oocysts and Giardia cysts, thus resulting in a risk for consumers