Genetic diversity of Toxoplasma gondii isolates obtained from free-living wild birds rescued in Southeastern Brazil.

W.M.F Rêgo,J.G.L Costa,R.C.A Baraviera,R.E.N Lopes,G.L Bessa,R.W.A Vitor,L.V Pinto,J.A.G Silveira

doi:10.1016/j.ijppaw.2018.11.001

Abstract

Recent studies carried out in Brazil have shown that strains from the same Toxoplasma gondii genotype can infect humans, domestic animals (dogs and cats) and animals slaughtered for human consumption (pigs, sheep, goats, and chickens), suggesting a common infection route. However, little is known about the importance of free-living wild birds within this epidemiological context. The objective of this work was to isolate, genotype, and evaluate the virulence for mice of new isolates of T. gondii obtained from free-living wild birds from the state of Minas Gerais, Southeastern Brazil. From August 2016 to June 2017, T. gondii was isolated from the hearts and brains collected from 6 out of 45 free-living wild birds, namely, a roadside hawk (Rupornis magnirostris), a campo flicker (Colaptes campestris), a southern caracara (Caracara plancus) and a tropical screech-owl (Megascops choliba), all rescued in Belo Horizonte. One isolate was obtained from a toco toucan (Ramphastos toco), rescued in Cristiano Otoni, and another was obtained from southern caracara, rescued in Santa Luzia. Five different genotypes were identified by PCR-RFLP. A unique genotype was shared in two different isolates obtained from a southern caracara and a toco toucan. This genotype has never been previously described in any other host or place. Three isolates were classified as of intermediary virulence and three isolates as avirulent for mice. The combined analysis of alleles ROP18/ROP5 (a serine/threonine kinase, and a polymorphic pseudokinase, respectively) was effective in determining the virulence of five of all the isolates with the exception of that from R. magnirostris. Atypical isolates of T. gondii obtained from free-living wild birds rescued in the state of Minas Gerais share the same genotypes of strains that infect humans, domestic animals, and animals slaughtered for human consumption.

Highlights

Toxoplasma gondii is an apicomplexan protozoan capable of causing neurological disturbances in the fetus, newborns, and in immunodeficient patients, mainly those with acquired immunodeficiency syndrome (AIDS)
Toxoplasma gondii has been isolated from humans, domestic animals, and animals slaughtered for human consumption in the state of Minas Gerais
The isolates were designated TgWildBrMG 1 to TgWildBrMG 6

Summary

Introduction

Toxoplasma gondii is an apicomplexan protozoan capable of causing neurological disturbances in the fetus, newborns, and in immunodeficient patients, mainly those with acquired immunodeficiency syndrome (AIDS). Bioassay to obtain new isolates of T. gondii is a current methodology, frequently used in the study of toxoplasmosis (Murata et al, 2018). This method is sensitive and allows obtaining viable parasites which can be used in subsequent biological studies. Such studies using freeliving wild birds are still scarce (Yai et al, 2008, 2009; Vitaliano et al, 2014). Little is known about the isolates of T. gondii that infect freeliving wild animals. This lack of information has a direct impact on understanding the biological and genotypic characteristics of T. gondii isolates present in the wild environment

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