Molecular Characterization of Blastocystis from Animals and Their Caregivers at the Gdańsk Zoo (Poland) and the Assessment of Zoonotic Transmission

Abstract

Blastocystis is a highly genetically diverse gut protist commonly found in humans and various animals. The role of animals in human infection is only partly understood. The aim of this study was to determine the host specificity and possibility of zoonotic transmission of this microorganism. Subtypes of Blastocystis isolated from 201 zoo animals and their 35 caregivers were identified by sequencing of the SSU rRNA gene. Blastocystis was found in 26.86% of animal and 17.14% of human samples. Both mammalian (ST1–ST3, ST5, ST8, ST10, ST13, ST14) and non-mammalian subtypes were detected. Of the subtypes found in non-human primates (ST1, ST2, ST3, and ST13), two subtypes (ST1 and ST3) were also detected in humans. The presence of identical ST1 sequences in three monkeys and their caregiver indicates the possibility of direct transmission of Blastocystis between these animals and humans. Detection of ST5 only in wild boars and peccaries, ST8 only in Marsupial, ST10 and ST14 only in Bovidae, and non-mammalian subtypes in reptiles suggests higher host specificity for these subtypes, and indicates that their transmission between animals and humans is unlikely. Additionally, this was probably the first time that ST5 was found in peccaries, ST2 in patas monkeys, and ST8 in red kangaroos.

Rare Occurrence of Blastocystis in Pet Animals and Their Owners in the Pomeranian Voivodeship in Poland in the Light of Literature Data

“…The Blastocystis nucleotide sequences obtained from the reptiles in this study differed significantly from the human and avian Blastocystis reference sequences from GenBank ( Figure 1 ). A similar pattern was seen in other reptile studies [ 1 , 37 , 80 ].…”

“…All subtypes have been reported in animals, which may suggest that animals could be a source of Blastocystis infection for humans. This seems to be confirmed by the few reports showing not only the presence of the same subtypes of Blastocystis , but also identical or very similar nucleotide sequences of Blastocystis isolated from animals and humans that are in close contact with each other [ 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. It is known that pet animals, such as dogs and cats, can be the source of many parasitic infections for humans, e.g., Toxocara canis / cati , Diphylidium caninum , Giardia intestinalis , Cryptosporidium spp., Sarcocystis spp., or Toxoplasma gondii .…”

Marked genetic diversity within Blastocystis in Australian wildlife revealed using a next generation sequencing–phylogenetic approach

“…Clearly, caution is warranted in making conclusions about an affiliation with a particular animal species in a captive environment, such as in parks, zoos or breeding/production facilities, due to cross transmission events of Blastocystis among species. There are also reports of ST13 in cervids in China, South Korea and UK ( Alfellani et al, 2013 ; Betts et al, 2018 ; Wang et al, 2018 ; Kim et al, 2020 ; Li et al, 2020 ; Chen et al, 2021 , 2022 ) and from primates in Bangladesh, China and Poland ( Li et al, 2019 ; Rudzińska et al, 2021 ; Geng, 2021- unpublished; Li et al, 2022 - unpublished), but none of these studies has provided sequence for >80% of the SSU-rRNA gene. Other key STs recorded in kangaroos and wallabies in previous studies include ST12, in the western grey kangaroo and northern swamp wallaby from zoos ( Parkar et al, 2010 ) and ST16, in red kangaroos from a zoo (Yoshikawa, 2011 - unpublished) (cf.…”

Blastocystis is widely distributed in mammals and aves

“…infection. However, the infection rates vary from 0% to 100% in different localities, such as most nonhuman primates in the three zoos in Hangzhou, Dalian and Suzhou (0%) [12], black-capped capuchin (0%) and rhesus macaque (96.6%) in Qingling Mountains [20], wild chimpanzees in southeast Cameroon (21.9%) [21], gorillas in the Beauval zoo in France (88.9%), common chimpanzees in Senegal (97.9%), gorillas in the Republic of the Congo (100%) [22], rhesus monkeys in Nepal (100%) [23], javan lutung and guereza in Poland (100%) [24]. Something similar was going on in the following four groups.…”