Prevalence of Giardia spp. in young dogs using a combination of two diagnostic methods

In this study, prevalence of the protozoan parasites from the genus Giardia spp, with zoonotic potential and worldwide dissemination, was accessed in young dogs, which are reported as having higher prevalence rates. With that purpose, 49 animals from the Grupo de Intervenção Cinotécnico of the Guarda Nacional Republicana (Portuguese Gendarmerie Canine Unit) were chosen. They were housed individually in areas with a high number of kennels (up to 100), with ages ragging from newborns to 10 years old. Dogs were divided in four groups, according their age: under 6 months (n = 16), 6-12 months (n = 6), 12-18 months (n = 13) and 18-24 months (n = 14), comprising 22 females and 27 males. Fecal samples were collected from every animal and all were submitted to two different diagnostic tests, a passive flotation technique with a ZnSO4 solution and a detection of fecal antigen using a commercially available ELISA test (Witness® Giardia - Zoetis). From the 49 samples, 5 (10.2%) were considered positive with ZnSO4 flotation technique and 6 (12.24%) with the Witness® Giardia test. When considering the combination of both tests, 5 animals (10.2%) were considered positive. Of these, 3 (60%) were from the group under 6 months old, 1 (20%) from the 6-12 months and 1 from the 18-24 (20%) months. Within each group, in the under 6 months group 18.75% (n = 16) were considered positive, 16.67% in the 6-12 month group (n = 6), 0% in the 12-18 month group (n=13) and 7.14% in 18-24 month group (n = 14). None of the animals had clinical signs and no significant differences were found when comparing prevalence according to age, breed or gender. A combination of fecal flotation and antigen ELISA tests have good sensitivity and are easy to perform in practice and, therefore, could be a good choice to perform a diagnostic and small animal veterinarians should have this possible diagnostic in mind when in the present of clinical signs, particularly in young dogs.