A two-year monitoring of Cryptosporidium spp. oocysts and Giardia spp. cysts in freshwater and seawater: A complementary strategy for measuring sanitary patterns of recreational tropical coastal areas from Brazil

Abstract

Primary contact recreation is an important transmission route of gastroenteric protozoa such as Cryptosporidium and Giardia. However, data on the environmental epidemiology of both protozoa in Brazilian coastal areas still need to be available. The main goal of this study was to perform environmental monitoring and quantify the concentration of Cryptosporidium oocysts and Giardia cysts on the main beaches of the state of Paraná, Brazil, as a complementary tool for measuring the sanitary quality of bathing waters for two years. A total of 144 water samples were harvested monthly for two years from Guaratuba, Caiobá and Matinhos beaches (72 samples of seawater and 72 of freshwater) to search for pathogenic protozoa. Protozoa were concentrated by the membrane filtration technique and visualized by direct immunofluorescence assay (IFA). All positive samples by IFA were submitted for DNA extraction for PCR analysis. Fecal indicator bacteria (FIB) were enumerated by conventional microbiological techniques. Both protozoa were detected on all beaches during the two-year monitoring period. At least one protozoa were detected in 58.3% (n = 14) months of sampling, totaling 24 positive samples. Guaratuba was the most contaminated beach followed by Caiobá and Matinhos. Giardia spp. was detected in 15, Cryptosporidium spp. in seven and both parasites in two samples. Giardia DNA was confirmed on two beaches, and Cryptosporidium was detected for the first time through molecular assays in a coastal area of Brazil. An essential impact of FIB was observed in the first year and a reduction in contamination rates in the second year of monitoring. This is the first study conducted in the country in different environments that composes coastal areas to monitor together parasitological and microbiological quality for extended periods. The monitoring of coastal waters can guide environmental agencies aiming to improve the sanitary quality of beaches and safeguard public health.