Toxoplasma gondii

Cabral, Aline Diniz, Su, Chunlei, Soares, Rodrigo Martins, Gennari, Solange Maria, Sperança, arcia Aparecida, Rosa, Adriana Ruckert da, F, Hilda & Pena, atima Jesus, 2021, Occurrence and diversity of Sarcocystidae protozoa in muscle and brain tissues of bats from Sao ˜ Paulo state, Brazil, International Journal for Parasitology: Parasites and Wildlife 14, pp. 91-96 : 93-95

3.2. T. gondii genotyping

Five bat tissues were positive for T. gondii , corresponding to four animals and three different species ( Table 1 ). Two non-archetypal genotypes were elucidated from two different specimens of the Eumops glaucinus insectivorous bat: ToxoDB-RFLP non-archetypal genotypes #6 (type BrI, Africa 1) and #69 (Table 2). An incomplete genotype was obtained from one Molossus molossus bat, with alleles II and I at GRA 6 and Apico markers, respectively.

4. Discussion

In the present study, detection of Sarcocystidae protozoa directly from muscle and brain tissues of bats was successfully performed through PCR amplification of a conserved 18S rRNA encoding sequence common to T. gondii , N. caninum , H. hammondi , N. eptesici , and S. neurona protozoa ( Su et al., 2010).

Except for the samples identified as T. gondii , confirmed as such by other molecular markers, the other candidate sarcocystids found in bats could not be accurately identified because the short 18S rRNA coding segment has little discriminatory value for unequivocal species identification. The identification of sarcocystids, especially within the genus Sarcocystis , must be based on multilocus analyses using barcoding markers as internal transcribed spacers within ribosomal loci, genes within the mitochondrial genome, or in apicoplasts and others ( Gjerde 2013; Kirillova et al., 2018; Cesar et al., 2018).

Nevertheless, 15 alleles were found among the 45 partial 18S sequences that were classified as non- T. gondii organisms and showed similarity of 96.1%–100% with other sarcocystids of cystoisoporinae, toxoplasmatinae, and sarcocystinae subfamilies. The 18S rDNA sequence screening suggests that bats in Brazil can harbour a large variety of Sarcocystidae organisms, even though molecular targets with higher phylogenetic resolution would be necessary to clarify these identities. Studies aiming to identify sarcocystids through molecular analysis employing other molecular markers have enormous potential to identify new species in bats, particularly if associated with morphological studies.

Herein, we report DNA similar to C. canis , S. (Frenkelia) glareoli (in the insectivorous bats M. molossus and Nyctinomops laticaudatus , respectively), and H. hammondi (in the nectarivorous Glossophaga soricina ) for the first time in bats. In addition, DNA similar to N. caninum was found in a G. soricina for the first time. Recently, a DNA fragment corresponding to the ribosomal internal transcribed spacer from N. caninum was also found in four Rhinolophus pusillus insectivorous bats ( Wang et al., 2018). These results show the importance of understanding the epidemiological chain of these protozoa in bats, the second largest globally distributed mammals with major ecological importance. The insectivorous and nectarivorous bats could be infected by Sarcocystidae parasites through ingestion of oocysts present in water, nectar, or mechanically carried by insects; bats could also be infected vertically in the case of T. gondii and N. caninum ( Dubey et al., 1988; Fayer et al., 2015; Donahoe et al., 2015).

Toxoplasma gondii is the most investigated parasite among the Sarcocystidae family due to its connection to human and veterinary health. Despite its high prevalence in humans and warm-blooded animal populations, only a small percentage of infected individuals exhibit clinical symptoms, thus demonstrating variability ( Dubey, 2010; Gilbert et al., 1999). In order to identify factors associated with variable clinical characteristics of toxoplasmosis, genotyping of T. gondii obtained from animals and humans have been performed around the world ( Shwab et al., 2014). Based on several studies, it was not possible to establish a clear relationship between clinical manifestations of toxoplasmosis and genotype variability. However, the T. gondii genotype profile presents differences in geographical and population structures. For example, isolated strains from Europe are predominantly type II; low genetic diversity was also observed in populations in Africa and Asia, where type II, III, and Chinese I are the most prevalent ( Shwab et al., 2014). In Central and South America, presence of higher genetic diversity maybe associated with recurrent infections ( Costa et al., 2018).

In this study, genotyping of T. gondii from two E. glaucinus insectivorous bats from the countryside of S˜ao Paulo revealed non-archetypal genotypes #69 and #6. The T. gondii genotype #69 has been described only in chickens in Brazil. Thus, this is the first report in bats. Genotype #6 (type BrI or Africa 1) is widely distributed across Africa and Brazil and in different host animals, including humans ( Shwab et al., 2014). However, it has been identified to circulate in Chiroptera for the first time. These results corroborate the high genetic variability of T. gondii in Brazil and the importance of bats as natural intermediate host for this zoonotic protozoan. Furthermore, as toxoplasmosis can be the cause of important neurological disease in bats, as described in megachiropteran from Australia ( Sangster et al., 2012), it would be advisable to include T. gondii as a differential diagnosis for neurological syndromes in bats.

The proximity between humans and bats in urban and rural areas is part of a broader scenario of environmental changes. Diseases can emerge as a result of new biological interactions between living species, caused by disturbance of the ecological balance. Habitat fragmentation is a dominant feature of the modern landscape ( Ewers and Didham, 2006), and species response to fragmentation has cascading effects on bat communities. Bats are considered an excellent bioindicator of environmental changes caused by human activities ( Jones et al., 2009).

In the present study, the importance of bats as reservoirs of Sarcocystidae parasites was investigated and it is suggested that the diagnosis of T. gondii should be included as differential for rabies and other neurological syndromes in this group of animals.