Objectives: Giardiasis is one of the human parasitic diseases by a flagellate protozoan
named Giardia lamblia. This parasite is one of the most common organisms causing diarrhea in
humans and a common gastrointestinal parasite in vertebrates. The purpose of this investigation was
to determine the molecular epidemiology of Giardia lamblia (G. lamblia) by PCR-RFLP method in
the Mazandaran Province and to investigate the possible relationship between parasite genotype and
Methods: In this study, 50 stool samples were collected from human cases of G. lamblia. referred to
health centers in Sari, Babol, Nowshahr cities. The samples were examined by formalin-ether concentration
procedure. DNA extraction was carried out on samples containing adequate Giardia
cysts, and then PCR-RFLP was done on glutamate dehydrogenase (gdh) marker.
Results: In these patients, the most common signs were abdominal pain (42.9%), and diarrhea
(47.6%); and least marked common sign was malaise (4.7%). Of all 21 isolates, 9 samples (42.8%)
were found as genotype mixed AII and BIII, 6 samples (28.6%) belonged to genotype BIII and 6
(28.6%) were of genotype AII. Additionally, there was a significant correlation between AII genotype
and clinical symptoms (P <0.05). According to the statistical tests, there was a significant relationship
between abdominal pain and the intensity of infection (P<0.05).
Conclusion: However, genotype AII and mixed AII and BIII genotypes were more common, respectively.
The relatively high prevalence of mixed infection of these genotypes indicated the potential
of zoonotic source of giardiasis among patients in Mazandaran Province.