Descrição
To understand the situation of water contamination with Cryptosporidium spp. and Giardia spp. in the northern
region of Portugal, we have established a long-term program aimed at pinpointing the sources of surface water and environmental
contamination, working with the water-supply industry. Here, we describe the results obtained with raw water
samples collected in rivers of the 5 hydrographical basins. A total of 283 samples were analyzed using the Method 1623
EPA, USA. Genetic characterization was performed by PCR and sequencing of genes 18S rRNA of Cryptosporidium spp.
and b-giardin of Giardia spp. Infectious stages of the protozoa were detected in 72.8% (206 of 283) of the water samples,
with 15.2% (43 of 283) positive for Giardia duodenalis cysts, 9.5% (27 of 283) positive for Cryptosporidium spp. oocysts,
and 48.1% (136 of 283) samples positive for both parasites. The most common zoonotic species found were G. duodenalis
assemblages A-I, A-II, B, and E genotypes, and Cryptosporidium parvum, Cryptosporidium andersoni, Cryptosporidium
hominis, and Cryptosporidium muris. These results suggest that cryptosporidiosis and giardiasis are important public health
issues in northern Portugal. To the authors’ knowledge, this is the first report evaluating the concentration of environmental
stages of Cryptosporidium and Giardia in raw water samples in the northern region of Portugal.
; Moreira, Maria João 
