Occurrence and molecular characterization of Enterocytozoon bieneusi in wild and domestic animal species in Portugal

Authors: FIGUEIREDO, ANA - University Of Aveiro (UA); DAHSTI, ALEJANDRO - National Center For Microbiology, The Institute Of Health Carlos Iii; Santin-Duran, Monica; KOSTER, PAMELA - National Center For Microbiology, The Institute Of Health Carlos Iii; TORRES, RITA - University Of Aveiro (UA); FONSECA, CARLOS - University Of Aveiro (UA); MYSTERUD, ATLE - University Of Oslo; CARVALHO, JOAO - University Of Aveiro (UA); SARMENTO, PEDRO - University Of Aveiro (UA); NEVES, NUNO - University Of Aveiro (UA); HIPÓLITO, DÁRIO - University Of Aveiro (UA); PALMEIRA, JOSMAN - University Of Aveiro (UA); TEIXEIRA, DANIELA - University Of Aveiro (UA); LIMA, CÁTIA - University Of Aveiro (UA)

Submitted to: Medical Mycology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2023
Publication Date: 2/6/2023
Citation: Figueiredo, A.M., Dahsti, A., Santin, M., Koster, P.C., Torres, R.T., Fonseca, C., Mysterud, A., Carvalho, J., Sarmento, P., Neves, N., Hipólito, D., Palmeira, J.D., Teixeira, D., Lima, C. 2023. Occurrence and molecular characterization of Enterocytozoon bieneusi in wild and domestic animal species in Portugal. Medical Mycology. 6(12). Article myad018. https://doi.org/10.1093/mmy/myad018.
DOI: https://doi.org/10.1093/mmy/myad018

Interpretive Summary: Enterocytozoon bieneusi is the most frequently reported Microsporidia species in humans and animals representing a global public and veterinary health concern. Despite the well-recognized role of wildlife as reservoirs of zoonotic pathogens, little is still known about the presence and epidemiology of E. bieneusi in wildlife. To fill this gap, a study to investigate occurrence and genetic diversity of E. bieneusi was conducted in wild and domestic mammals from different regions throughout Portugal. A total of 756 faecal samples were collected from 228, 242, and 226 wild carnivores, wild ungulates, and livestock, respectively. Positive samples were identified from five wild animals (Iberian lynx, Iberian wolf, red fox, stone marten, and wild boar) and one livestock host (sheep). Nucleotide sequence analysis identified four genotypes of E. bieneusi, Type IV, Wildboar3, BEB6, and PtEbIX. Three of those genotypes belong to Groups 1 (Type IV and Wildboar3) and 2 (BEB6) that are known to contain genotypes capable of infecting a variety of hosts, including humans, highlighting their public health importance. This study represents the first, largest, and most comprehensive molecular-based epidemiology survey carried out in Portugal in wild and domestic animals to date and the first worldwide identification of E. bieneusi in wolf species. The study showed that wild carnivores and ungulates are reservoirs of zoonotic E. bieneusi genotypes, establishing their role in maintaining the sylvatic cycle of this parasite while representing a potential source of infection for humans and domestic animals. Data expand knowledge on the epidemiology, host range, and molecular diversity of E. bieneusi that will be useful to other scientists, veterinarians, and public health agencies in understanding zoonotic potential and public health importance of this infectious pathogen.

Technical Abstract: The phylum Microsporidia encompasses a diverse group of obligate, intracellular, and spore-forming organisms able to infect a wide range of animal hosts. Among them, Enterocytozoon bieneusi is the most frequently reported species in humans and animals. Despite the well-recognized role of wildlife as reservoirs of zoonotic reservoirs, little is known about the presence and epidemiology of E. bieneusi in wildlife. To fill this gap, we investigated E. bieneusi occurrence and genetic diversity in wild and domestic mammals, through molecular-detection methods, from different regions throughout Portugal. A total of 756 faecal samples were collected from 228, 242, and 226 wild carnivores, wild ungulates, and livestock, respectively. Overall, eight specimens were E. bieneusi-positive (1.1%, 8/756) obtained from five wild (Iberian lynx, Iberian wolf, red fox, stone marten, and wild boar) and one domestic (sheep) hosts. Nucleotide sequence analysis identified four genotypes of E. bieneusi, Type IV, Wildboar3, BEB6, and PtEbIX. Three of those genotypes belong to Groups 1 (Type IV and Wildboar3) and 2 (BEB6) that are known to contain genotypes capable of infecting a variety of hosts, including humans, highlighting their public health importance. PtEbIX belongs to the dog-specific Group 11. This study represents the first, largest and most comprehensive molecular-based epidemiology survey carried out in Portugal in wild and domestic animals to date and the first worldwide identification of E. bieneusi in wolf species. Our study showed that wild carnivores and ungulates are reservoirs of zoonotic genotypes of E. bieneusi, establishing their role in maintaining the sylvatic cycle of this parasite while representing a potential source of infection for humans and domestic animals.