Giardia spp. are the causative agents of intestinal infections in a wide variety of mammals including humans and companion animals. Dogs may be reservoirs of zoonotic Giardia spp.; however, the potential for transmission between dogs and humans in Jamaica has not been studied. Conventional PCR was used to screen 285 human and 225 dog stool samples for Giardia targeting the SSU rDNA gene followed by multilocus sequencing of the triosephosphate isomerase (tpi), glutamate dehydrogenase (gdh), and β-giardin (bg) genes. Prevalence of human infections based on PCR was 6.7 % (19/285) and canine infections 19.6 % (44/225). Nested PCR conducted on all 63 positive samples revealed the exclusive presence of assemblage A in both humans and dogs. Sub-assemblage A-II was responsible for 79.0 % (15/19) and 70.5 % (31/44) of the infections in humans and dogs, respectively, while sub-assemblage A-I was identified at a rate of 15.8 % (3/19) and 29.5 % (13/44) in humans and dogs, respectively. The predominance of a single circulating assemblage among both humans and dogs in Jamaica suggests possible zoonotic transmission of Giardia infections.

Canine and feline hookworms are important causes of skin infections in humans including creeping eruption or cutaneous larva migrans. Further, Ancylostoma caninum has been shown to cause intestinal infections in humans resulting in eosinophilic enteritis. To determine the prevalence of Ancylostoma species in dogs and possible intestinal exposure of humans in Jamaica, stool samples from both species were screened using PCR targeting the internal transcribed spacer (ITS-1), 5,8S and ITS-2 region of the ribosomal DNA genes. The prevalence of hookworm infections in dogs based on PCR was 60.9% (78/128). DNA sequencing revealed that A. caninum accounted for 88.2% (30/34) and A. braziliense for 11.8% (4/34) of infections in dogs. Further, DNA of A. caninum targeting the same gene fragment was identified in 22.1% (17/77) of stool samples from patients presenting at hospital with the gastrointestinal symptoms. This report of molecular identification of A. caninum DNA in human stools provide further support that intestinal infection with this parasite may be underreported in endemic areas.