ORIGINAL PAPER Molecular epidemiology and multilocus sequence analysis of potentially zoonotic Giardia spp. from humans and dogs in Jamaica Mellesia F. Lee 1,4 & Paul Cadogan 2 & Sarah Eytle 2 & Sonia Copeland 3 & Julia Walochnik 4 & John F. Lindo 1 Received: 15 June 2016 /Accepted: 18 October 2016 # Springer-Verlag Berlin Heidelberg 2016 Abstract 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 re- vealed 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 identi- fied at a rate of 15.8 % (3/19) and 29.5 % (13/44) in humans and dogs, respectively. The predominance of a single circulat- ing assemblage among both humans and dogs in Jamaica suggests possible zoonotic transmission of Giardia infections. Keywords Giardia . Dogs . Humans . Jamaica . Zoonotic transmission . Assemblages Introduction Giardia duodenalis (synonyms G. lamblia and G. intestinalis) is one of the most common intestinal parasites worldwide and an important cause of waterborne and foodborne infections in humans (Adam 2001; Adams et al. 2004). Giardia infections are re-emerging with just under 200 million symptomatic cases and up to 500,000 new cases per year (Pires et al. 2015). They are a common cause of diarrhea in developing countries and poor communities in the developed world (Pires et al. 2015). The global distribution of the parasite is attribut- able to its resilient infectious cysts, which can persist for long periods in harsh environmental conditions (Feng and Xiao 2011). Infection by Giardia is initiated when cysts are ingested from contaminated water, food, or direct fecal–oral contact (Thompson and Monis 2012). After ingestion, excystment triggers release of motile trophozoites in the small intestine and encystation in the large intestine (Thompson and Monis 2012). However, in symptomatic hosts with diarrhea, there is no encystment and trophozoites are excreted which die soon after passage (Thompson and Monis 2012). Giardia isolated from mammals has been divided into host- specific assemblages (A-H) which have been proposed as separate species (Thompson and Monis 2004). Assemblages A, referred to as G. duodenalis, and assemblage B, referred to as G. enterica, are zoonotic having a broad host range and infect predominantly humans, dogs, and cats (McGlade et al. 2003; Paz e Silva et al. 2012). Unlike A and B, assemblages C and D have strong host specificities and are most commonly found in dogs, foxes, and other canines; assemblage E in live- stock (cattle, sheep, pigs) and assemblages F and G are com- monly found in cats and rodents, while H was identified in seals and gulls (Adam 2001; Feng and Xiao 2011). Initially, allozyme along with phylogenetic analysis resulted in sub- clustering within assemblages A and B, namely, A-I, A-II, * John F. Lindo john.lindo@uwimona.edu.jm 1 Department of Microbiology, University of the West Indies, Mona, Kingston 7, Jamaica 2 Jamaica Veterinary Medical Association, Kingston, Jamaica 3 Ministry of Health, Kingston, Jamaica 4 Institute of Specific Prophylaxis and Tropical Medicine, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria Parasitol Res DOI 10.1007/s00436-016-5304-y