Document Type : Original Article


1 Department of Pathobiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

2 Department of Internal Medicine and Clinical Pathology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran


Giardia duodenalis is a zoonotic protozoan infecting various vertebrates such as humans and domestic animals. The aim of this study was to determine the frequency and genotypes of G. duodenalis using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in dogs of Urmia, Iran. Overall, 246 stool specimens were collected from 100 pet, 49 stray, and 97 shelter dogs in the Urmia, Iran. Totally, seven samples (2.48%) were microscopically positive in terms of Giardia cyst. The PCR-RFLP analysis revealed that three (1.21%) and two (0.83%) samples have the C and D genotypes, respectively. In addition, two samples (0.83%) were belonged to the AI sub-group. A significant association was determined between the frequency of Giardia infection and life style, age, and stool form of dogs. The findings of the study showed the high frequency of Giardia infection in stray dogs and the dogs under one-year-old. Furthermore, the C and D genotypes of G. duodenalis were predominant in dogs of Urmia, Iran.


  1. Read CM, Monis PT, Thompson RC. Discrimination of all genotypes of Giardia duodenalis at the glutamate dehydrogenase locus using PCR-RFLP. Infect Genet Evol 2004; 4(2): 125-130.
  2. Fazaeli A, Kohansal MH, Spotin A, et al. Infection rate and genetic diversity of Giardia duodenalis assemblage C in Iranian stray dogs, targeting the glutamate dehydrogenase gene. Vet World 2021; 14(2): 419-425.
  3. Horlock-Roberts K, Reaume C, Dayer G, et al. Drug-free approach to study the unusual cell cycle of Giardia intestinalis. mSphere 2017; 2(5): e00384-16. doi: 10.1128/mSphere.00384-16.
  4. Berrilli F, D’Alfonso R, Giangaspero A, et al. Giardia duodenalis genotypes and Cryptosporidium species in humans and domestic animals in Côte d’Ivoire: occurrence and evidence for environmental contamination. Trans R Soc Trop Med Hyg 2012; 106(3): 191-195.
  5. de Lucio A, Bailo B, Aguilera M, et al. No molecular epidemiological evidence supporting household transmission of zoonotic Giardia duodenalis and Cryptosporidium from pet dogs and cats in the province of Álava, Northern Spain. Acta Trop 2017; 170: 48-56.
  6. Monis PT, Andrews RH, Mayrhofer G, et al. Genetic diversity within the morphological species Giardia intestinalis and its relationship to host origin. Infect Genet Evol 2003; 3(1): 29-38.
  7. Xiao L, Fayer R. Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission. Int J Parasitol 2008; 38(11): 1239-1255.
  8. Monis PT, Thompson RC. Cryptosporidium and Giardia-zoonoses: fact or fiction? Infect Genet Evol 2003; 3(4): 233-244.
  9. Thompson RC. Giardiasis as a re-emerging infectious disease and its zoonotic potential. Int J Parasitol 2000; 30(12-13): 1259-1267.
  10. Olson ME, O’Handley RM, Ralston BJ, et al. Update on Cryptosporidium and Giardia infections in cattle. Trends Parasitol 2004; 20(4): 185-191.
  11. Arani AS, Alaghehbandan R, Akhlaghi L, et al. Prevalence of intestinal parasites in a population in south of Tehran, Iran. Rev Inst Med Trop Sao Paulo 2008; 50(3): 145-149.
  12. Mohammed Mahdy AK, Surin J, Wan KL, et al. Giardia intestinalis genotypes: Risk factors and correlation with clinical symptoms. Acta Trop 2009; 112(1): 67-70.
  13. Fallah E, Nahavandi KH, Jamali R, et al. Molecular identification of Giardia duodenalis isolates from human and animal reservoirs by PCR-RFLP. J Biol Sci 2008; 8(5): 896-901.
  14. Hazrati Tappeh K, Manafi G, Asgharzadeh M, et al. Incidence of Giardia lamblia subspecies by PCR-RFLP in stool specimens of hospitalized children at Urmia Mutahhari hospital, West Azerbaijan province, Iran. Iran J Parasitol 2014; 9(4):541-547.
  15. Itagaki T, Kinoshita S, Aoki M, et al. Genotyping of Giardia intestinalis from domestic and wild animals in Japan using glutamete dehydrogenase gene sequencing Vet Parasitol 2005; 133(4): 283-287.
  16. Wielinga CM, Thompson RC. Comparative evaluation of Giardia duodenalis sequence data. Parasitology 2007; 134(Pt 12): 1795-1821.
  17. Plutzer J, Ongerth J, Karanis P. Giardia taxonomy, phylogeny and epidemiology: Facts and open questions. Int J Hyg Environ Health 2010; 213(5): 321-333.
  18. Kohansal MH, Fazaeli A, Nourian A, et al. Dogs’ gastrointestinal parasites and their association with public health in Iran. J Vet Res 2017; 61(2): 189-195.
  19. Sarvi S, Daryani A, Sharif M, et al. Zoonotic intestinal parasites of carnivores: A systematic review in Iran. Vet World 2018. 11(1): 58-65.
  20. Homayouni MM, Razavi SM, Shaddel M, et al. Prevalence and molecular characterization of Cryptosporidium spp. and Giardia intestinalis in household dogs and cats from Shiraz, Southwestern Iran. Vet Ital 2019; 55(4): 311-318.
  21. Yakhchali M, Hosseini A. Prevalence and ectoparasites fauna of sheep and goats flocks in Urmia suburb, Iran. Vet Arh 2006; 76(5): 431-442.
  22. Luchtel DL, Lawrence WP, DeWalle FB. Electron microscopy of Giardia lamblia Appl Environ Microbiol 1980; 40(4): 821-832.
  23. Bertrand I, Albertini L, Schwartzbrod J. Comparison of two target genes for detection and genotyping of Giardia lamblia in human feces by PCR and PCR-restriction fragment length polymorphism. J Clin Microbiol 2005; 43(12): 5940-5944.
  24. Malekifard F, Ahmadpour M. Molecular detection and identification of Giardia duodenalis in cattle of Urmia, northwest of Iran. Vet Res Forum 2018; 9(1): 81-85.
  25. Mirzaei M. Prevalence of stray dogs with intestinal protozoan parasites. Am J Anim Vet Sci 2010; 5(2): 86-90.
  26. Garedaghi Y, Karimi B. Prevalence of intestinal protozoan parasites in stray dogs of Tabriz city, Iran. Indian J Fundam Appl Life Sci 2014; 4(2): 20-24.
  27. Silva MS, Uzêda RS, Costa KS, et al. Detection of Hammondia heydorni and related coccidia (Neospora caninum and Toxoplasma gondii) in goats slaughtered in Bahia, Brazil. Vet Parasitol 2009; 162(1-2): 156-159.
  28. Tseng YC, Ho GD, Chen T TW, et al. Prevalence and genotype of Giardia duodenalis from faecal samples of stray dogs in Hualien city of eastern Taiwan. Trop Biomed 2014; 31(2): 305-311.
  29. Qi M, Dong H, Wang R, et al. Infection rate and genetic diversity of Giardia duodenalis in pet and stray dogs in Henan Province, China. Parasitol Int 2016; 65(2): 159-162.
  30. Upjohn M, Cobb C, Monger J, et al. Prevalence, molecular typing and risk factor analysis for Giardia duodenalis infections in dogs in a central London rescue shelter. Vet Parasitol 2010; 172(3-4): 341-346.
  31. Uiterwijk M, Nijsse R, Kooyman FNJ, et al. Host factors associated with Giardia duodenalis infection in dogs across multiple diagnostic tests. Parasit Vectors 2019; 12(1): 556. doi: 10.1186/s13071-019-3810-3
  32. Shin JC, Reyes AW, Kim SH, et al. Molecular detection of Giardia intestinalis from stray dogs in animal shelters of Gyeongsangbuk-do (Province) and Daejeon, Korea. Korean J Parasitol 2015; 53(4): 477-481.
  33. Huber F, Bomfim TC, Gomes RS. Comparison between natural infection by Cryptosporidium, Giardia sp. in dogs in two living situations in the West Zone of the municipality of Rio de Janeiro. Vet Parasitol 2005; 130(1-2): 69-72.
  34. Bugg RJ, Robertson ID, Elliot AD, et al. Gastrointestinal parasites of urban dogs in Perth, Western Australia. Vet J 1999; 157(3): 295-301.
  35. Liu J, Lee SE, Song KH. Prevalence of canine giardiosis in South Korea. Res Vet Sci 2008; 84(3): 416-418.
  36. Broglia A, Weitzel T, Harms G, et al. Molecular typing of Giardia duodenalis isolates from German travellers. Parasitol Res 2013; 112(10): 3449-3456.
  37. Štrkolcová G, Maďar M, Hinney B, et al. Dog’s genotype of Giardia duodenalis in human: first evidence in Europe. Acta Parasitol 2015; 60(4): 796-799.
  38. Gelanew T, Lalle M, Hailu A, et al. Molecular characterization of human isolates of Giardia duodenalis from Ethiopia. Acta Trop 2007; 102(2): 92-99.
  39. Feng Y, Xiao L. Zoonotic potential and molecular epidemiology of Giardia species and giardiasis. Clin Microbiol Rev 2011; 24(1): 110-140.
  40. Spotin A, Karamat M, Mahami-Oskouei M, et al. Genetic variability and transcontinental sharing of Giardia duodenalis infrapopulations determined by glutamate dehydrogenase gene. Acta Trop 2018; 177: 146-156.
  41. Monis PT, Mayrhofer G, Andrews RH, et al. Molecular genetic analysis of Giardia intestinalis isolates at the glutamate dehydrogenase locus. Parasitology 1996; 112(Pt 1): 1-12.
  42. Traub RJ, Monis PT, Robertson I, et al. Epidemiological and molecular evidence supports the zoonotic transmission of Giardia among humans and dogs living in the same community. Parasitology 2004; 128(Pt 3): 253-262.
  43. Cacciò SM, Ryan U. Molecular epidemiology of giardiasis. Mol Biochem Parasitol 2008; 160(2): 75-80.
  44. Robertson LJ, Forberg T, Hermansen L, et al. Giardia duodenalis cysts isolated from wild moose and reindeer in Norway: genetic characterization by PCR-RFLP and sequence analysis at two genes. J Wildl Dis 2007; 43(4): 576-585.
  45. Tan L, Wu S, Abdullahi AY, et al. PCR-RFLP method to detect zoonotic and host-specific Giardia duodenalis assemblages in dog fecal samples. Parasitol Res 2016; 115(5): 2045-2050.
  46. Szénási Z, Marton S, Kucsera I, et al. Preliminary investigation of the prevalence and genotype distribution of Giardia intestinalis in dogs in Hungary. Parasitol Res 2007; 101(Suppl 1): 145-152.
  47. Zheng G, Alsarakibi M, Liu Y, et al. Genotyping of Giardia duodenalis isolates from dogs in Guangdong, China based on multi-locus sequence. Korean J Parasitol 2014; 52(3): 299-304.
  48. Souza SL, Gennari SM, Richtzenhain LJ, et al. Molecular identification of Giardia duodenalis isolates from humans, dogs, cats and cattle from the state of São Paulo, Brazil, by sequence analysis of fragments of glutamate dehydrogenase (gdh) coding gene. Vet Parasitol 2007; 149(3-4): 258-264.
  49. Ballweber LR, Xiao L, Bowman DD, et al. Giardiasis in dogs and cats: update on epidemiology and public health significance. Trends Parasitol 2010; 26(4): 180-189.
  50. Adell-Aledón M, Köster PC, de Lucio A, et al. Occurrence and molecular epidemiology of Giardia duodenalis infection in dog populations in eastern Spain. BMC Vet Res 2018; 14:26. doi: 10.1186/s12917-018-1353-z.