On the other hand, Giardia was detected by PCR in samples S2
and S12 (Table 3). Sequences from these samples corresponded to
Giardia duodenalis genotypes B and AI respectively. Its presence in
washing coarse solids suggests that the purification process is
being effective for removing this parasite, which is then collected
in the ATAD sludge outflow. The G. duodenalis genotype B found in
S2 correspond to a genotypewhich produces intestinal infection in
humans with a high prevalence in Spain (Goñi et al., 2010); while
genotype AI (S12) has not been found in our country affecting
humans, but pets and livestock (Gómez-Muñoz et al. (2012)). The
DNA sequences for the two identified Giardia isolates have been
deposited in the Genetic sequence database at the National Center
for Biotechnical Information (NCBI) under accession numbers
KC525960 and KC525961. It is important to note that the detection
of DNA of Giardia not imply the presence of viable cysts, so further
study would be necessary to determine this aspect to ensure the
safe reuse of sludge in agriculture.