Molecular Detection and Distribution of Giardia duodenalis and Cryptosporidium spp. Infections in Wild and Domestic Animals in Portugal

Abstract

Enteric protozoan parasites Giardia duodenalis, Cryptosporidium spp., and, to a lesser extent, the ciliate Balantioides coli are responsible for severe human and animal intestinal disorders globally. However, limited information is available on the occurrence and epidemiology of these parasites in domestic, but especially wild species in Portugal. To fill this gap of knowledge, we have investigated G. duodenalis, Cryptosporidium spp., and B. coli occurrence, distribution, genetic diversity, and zoonotic potential by analyzing 756 fecal samples from several wild carnivores (n = 288), wild ungulates (n = 242), and domestic species (n = 226) collected across different areas of mainland Portugal. Overall, infection rates were 16.1% (122/756; 95% CI: 13.59–18.96) for G. duodenalis and 2.7% (20/756; CI: 1.62–4.06) for Cryptosporidium spp., while no ungulate sample analyzed yielded positive results for B. coli. Giardia duodenalis was found across a wide range of hosts and sampling areas, being most prevalent in the Iberian lynx (26.7%), the Iberian wolf (24.0%), and the domestic dog (23.9%). Cryptosporidium spp. was only identified in wild boar (8.4%), red fox (3.4%), Iberian lynx (3.3%), red deer (3.1%), and Iberian wolf (2.5%). Sequence analysis of G. duodenalis determined zoonotic assemblage A (subassemblage AI) in one roe deer sample, canine-specific assemblages C and D in Iberian wolf, red fox, and domestic dog, and ungulate-specific assemblage E in wild boar, sheep, cattle, and horse. Six Cryptosporidium species were identified: C. scrofarum in wild boar, C. canis in the Iberian wolf and red fox, C. ubiquitum in red deer and wild boar, C. felis in the Iberian lynx, and both C. ryanae and C. occultus in red deer. Giardia duodenalis and Cryptosporidium spp. coinfections were observed in 0.7% (5/756) of the samples. This is the first, most comprehensive, and largest molecular-based epidemiology study of its kind carried out in Portugal, covering a wide range of wild and domestic hosts and sampling areas. The detection of zoonotic Cryptosporidium spp. and G. duodenalis subassemblage AI demonstrates the role of wild and domestic host species in the transmission of these agents while representing a potential source of environmental contamination for other animals and humans.

Detection and Molecular Diversity of Cryptosporidium spp. and Giardia duodenalis in the Endangered Iberian Lynx (Lynx pardinus), Spain

“…In Europe, at least 11 Cryptosporidium species (C. alticolis, C. andersoni, C. bovis, C. canis, C. ditrichi, C. erinacei, C. felis, C. hominis, C. parvum, C. suis, and C. ubiquitum) and four genotypes (mink genotype, muskrat genotype, skunk genotype, and vole genotype) have been identified in 18 free-living carnivore species belonging to 12 genera and six families in the last 20 years (Table 1). The skunk genotype (24.2%, 32/132), C. canis (18.9%, 25/132), and C. ditrichi (16.7%, 22/132) were the most prevalent Cryptosporidium genetic variants found, whereas the red fox (n = 770) and the raccoon (n = 165) were the most investigated carnivore host species (Table 1) [14][15][16][17][18][19][20][21][22][23][24][25]. There are nine validated Giardia species in various vertebrates, namely G. agilis in amphibians; G. ardeae and G. psittaci in birds; G. cricetidarum, G. microti, G. muris, and G. paramelis in rodents; G varani in reptiles; and G. duodenalis in mammals including humans [13].…”

A Thorny Tale of Parasites: Screening for Enteric Protozoan Parasites in Hedgehogs from Portugal

“…Transmission occurs by ingesting resistant cysts (Blastocystis sp., B. coli, and G. duodenalis) or oocysts (Cryptosporidium spp.) [5][6][7][8]. Infection can be direct (human-to-human, animal-to-human) or indirect when exposed to contaminated water and food [8].…”

“…[5][6][7][8]. Infection can be direct (human-to-human, animal-to-human) or indirect when exposed to contaminated water and food [8]. Common symptoms and clinical signs of enteric protozoa found in humans and animals are acute diarrhea, abdominal pain, malabsorption, dehydration, anorexia, and weight loss [5,7,9,10].…”

“…Pigs are considered the main reservoirs, but other species, such as camels, cattle, donkeys, sheep, and goats, have been proposed as potential reservoirs [3,18]. Worldwide prevalence in humans typically does not exceed 1% [8]. The parasite has a direct life cycle, with a vegetative form, trophozoites, residing in the host intestine, and a resting cyst that is released into the environment in feces [18].…”

“…Its life cycle consists of two stages: a fecally-orally transmitted cyst and a disease-causing trophozoite [26]. G. duodenalis is categorized into eight distinct assemblages (genotypes A-H), distinguished by host specificity and genetic variations [8,25]. Assemblages A and B specifically infect humans, and certain sub-genotypes exhibit zoonotic potential [25].…”