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Abstract Background Microsporidia is a large group of eukaryotic obligate intracellular spore-forming parasites, of which 17 species can cause microsporidiosis in humans. Most human-infecting microsporidians belong to the genera Enterocytozoon and Encephalitozoon. To date, only five microsporidian species, including Encephalitozoon-like, have been found in hard ticks (Ixodidae) using microscopic methods, but no sequence data are available for them. Furthermore, no widespread screening for microsporidian-infected ticks based on DNA analysis has been carried out to date. Thus, in this study, we applied a recently developed DNA metabarcoding method for efficient microsporidian DNA identification to assess the role of ticks as potential vectors of microsporidian species causing diseases in humans. Methods In total, 1070 (493 juvenile and 577 adult) unfed host-seeking Ixodes ricinus ticks collected at urban parks in the city of Poznan, Poland, and 94 engorged tick females fed on dogs and cats were screened for microsporidian DNA. Microsporidians were detected by PCR amplification and sequencing of the hypervariable V5 region of 18S rRNA gene (18S profiling) using the microsporidian-specific primer set. Tick species were identified morphologically and confirmed by amplification and sequencing of the shortened fragment of cytochrome c oxidase subunit I gene (mini-COI). Results All collected ticks were unambiguously assigned to I. ricinus. Potentially zoonotic Encephalitozoon intestinalis was identified in three fed ticks (3.2%) collected from three different dogs. In eight unfed host-seeking ticks (0.8%), including three males (1.1%), two females (0.7%) and three nymphs (0.7%), the new microsporidian sequence representing a species belonging to the genus Endoreticulatus was identified. Conclusions The lack of zoonotic microsporidians in host-seeking ticks suggests that I. ricinus is not involved in transmission of human-infecting microsporidians. Moreover, a very low occurrence of the other microsporidian species in both fed and host-seeking ticks implies that mechanisms exist to defend ticks against infection with these parasites. Graphical abstract

An intensive, long-term monitoring study was conducted of a variety of ecologically diverse group of free-ranging, captive and domestic livestock birds for characterizing the potential input of human-infectious microsporidian spores from avian hosts. Results demonstrated that waterborne microsporidian spores of species that infect people could originate from common waterfowl, which usually occur in huge numbers and have unlimited access to surface waters, including water used for production of drinking water.

A study is conducted to demonstrate that fresh food produce sold at the retail level can contain potentially viable microsporidian spores of human virulent species. These species represents a threat of food borne infection.

Abstract??Human microsporidiosis, a serious disease of immunocompetent and immunosuppressed people, can be due to zoonotic transmission of microsporidian spores. A survey utilizing chromotrope 2R stain and fluorescent in situ hybridization techniques for testing feces from 193 captive mammals demonstrated that 3 animals (1.6%) shedEncephalitozoon bieneusispores. These include two critically endangered species (i.e., black lemurs,Eulemur macaco flavifrons; and Visayan warty pig,Sus cebifrons negrinus) and a threatened species (mongoose lemur,Eulemur mongoz). The concentration of spores varied from 2.7???105to 5.7???105/g of feces, and all infections were asymptomatic. The study demonstrates thatE. bieneusispores can originate from captive animals, which is of particular epidemiologic importance because the close containment of zoological gardens can facilitate pathogen spread to other animals and also to people such as zoo personnel and visitors. [ABSTRACT FROM AUTHOR]