Prevalence, Subtype Distribution and Zoonotic Significance of Blastocystis sp. Isolates from Poultry, Cattle and Pets in Northern Egypt

Abstract

Blastocystis sp. is a widespread enteric protozoan that frequently infects human and animal groups. Despite its burden and zoonotic potential worldwide, epidemiological investigations remain limited in animal groups that come in contact with humans. Therefore, the largest survey ever conducted in North Africa was performed in Egypt with the aim to investigate the prevalence and subtype (ST) distribution of Blastocystis sp. in animals. For this purpose, a total of 889 fecal specimens were collected from chickens (217), cattle (373), dogs (144) and cats (155) from six governorates of northern Egypt. These specimens were then screened for the presence of Blastocystis sp. using a quantitative real-time PCR, followed by subtyping the isolates. The overall prevalence of Blastocystis sp. reached 9.2% (82/889), with the highest infection rates reported in chickens (17.0%) and domestic cattle (11.0%), highlighting an active circulation of the parasite in both animal groups. In contrast, the low prevalence in cats (2.6%) and the absence of the parasite in dogs suggested that pets are not natural hosts of Blastocystis sp. ST10 and ST14 were largely predominant in cattle, confirming that both STs represented cattle-adapted STs. The report of one ST3 and one ST4 isolate in this animal group could be explained by an accidental zoonosis from humans to animals. All but one of the subtyped isolates in poultry belonged to ST7, which was considered as an avian ST. The presence of a remaining isolate of ST14 likely reflected a transient infection from contact between birds and cattle feces. The same environmental contamination was also likely the source of the ST14 infection in three of the four positive cats, with the remaining animals infected by ST3 as the result of human-to-animal transmission. These occurrences and subtyping data, combined with those previously collected in the Egyptian population, implies that poultry could play a significant role as reservoir for zoonotic transmission, which would not be the case for cattle and pets.

Molecular Identification and Subtype Analysis of Blastocystis sp. Isolates from Wild Mussels (Mytilus edulis) in Northern France

“…This proportion of mixed infections in the positive samples analyzed was of the same order of importance for mussels collected at Wimereux (18/34, 52.9%) as for those sampled at Dannes (29/48, 60.4%). High proportions of mixed infections have also been reported in numerous other animal groups, as recently described [5,29,51], definitely related to multiple sources of contamination in their respective environment. The remaining 35 chromatograms reflected single infections in either gills or intestinal tract of mussels from the two sampling points.…”

Molecular characteristics and zoonotic potential of enteric protists in domestic dogs and cats in Egypt

“…On the other side, Blastocystis sp. colonization/infection has been detected at low rates in domestic dogs by conventional microscopy (3.1%) and cats by PCR (2.6%) ( 28 , 38 ), although other surveys failed to identify the presence of the protist using culture and PCR methods ( 38 , 39 ).…”

First Epidemiological Survey on the Prevalence and Subtypes Distribution of the Enteric Parasite Blastocystis sp. in Vietnam

“…STs. To provide insight into the distribution of STs in mixed infections, some specimens were selected based on the qPCR amplification intensity for reanalysis by end-point PCR, using the same primer pair as for qPCR, as previously detailed [ 40 ]. The PCR products obtained and visualized on agarose gel were purified using the NucleoSpin Gel and PCR Clean-up kit (Macherey-Nagel GmbH & Co KG), cloned in the T-vector TA pCR–TOPO 2.1 of the TOPO TA cloning kit (Invitrogen, Carlsbad, CA, USA) following the manufacturer’s protocol, then amplified in One Shot TOP10 Chemically Competent Escherichia coli (Invitrogen).…”