RESUMO
Toxoplasma gondii is a zoonotic parasite which can infect almost all warm-blooded animals. Toxoplasma gondii isolates from Brazil have greater genetic diversity with a predominance of virulent and atypical genotypes, compared with the Northern Hemisphere. Considering that previous studies have demonstrated a high seroprevalence of T. gondii antibodies in animals from Fernando de Noronha Island, the aim of this study was to isolate, genetically characterize, and determine mouse virulence of isolates of T. gondii from livestock from this Brazilian island. Two T. gondii isolates were obtained by mouse bioassay from brain from one sheep and one pig. Genotyping was performed by PCR-RFLP using 10 genetic markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22- 8, c29-2, PK1, L358, and Apico) and an atypical genotype of T. gondii (ToxoDB #146) was identified for both isolates. Genotyping of four ROP loci indicated different alleles for ROP16 and mouse virulence analysis revealed different profiles (intermediate and low virulence). This is the first report of this genotype being described in a pig and a sheep.
Assuntos
Toxoplasma/genética , Toxoplasma/isolamento & purificação , Toxoplasmose Animal/parasitologia , Animais , Brasil , Variação Genética , Genótipo , Ilhas , Camundongos , Proteínas de Protozoários/genética , Ovinos , Suínos , Toxoplasma/classificação , Virulência/genéticaRESUMO
BACKGROUND: Toxoplasma gondii is a zoonotic parasite of global importance. The outcome of infection in humans can depend on a number of factors including the infecting stage of the parasite, inoculating dose and virulence of the infecting strain. Molecular epidemiological studies have demonstrated an abundance of atypical strains of T. gondii in South America, many of which have been associated with more severe sequelae of infection. The aim of this study was to compare the virulence of T. gondii strains isolated in the Caribbean to a virulent Brazilian strain and an avirulent European strain. METHODS: One hundred and twenty Swiss CD-1 mice were split into 8 groups of 15 mice and each group was inoculated with 200 tachyzoites of one of 8 isolates, comprising ToxoDB genotypes #1, #141, #265, #13, #3 and #6. Five mice per group were euthanized at day 8 post-inoculation (p.i.) and parasite burden was determined in heart, lungs and eyes using quantitative PCR. Lungs and brain were also examined by histopathology and immunohistochemistry. The remaining 10 mice per group were part of a survival experiment to assess virulence. DNA was extracted from tachyzoites of each of the 8 T. gondii isolates and genotyped at four ROP gene loci, including ROP5, ROP16, ROP17 and ROP18 to look for association with markers of virulence. RESULTS: Infection with ToxoDB genotype #13 from the Caribbean resulted in 100% of mice being euthanized which was comparative to infection with the virulent Brazilian strain (ToxoDB genotype #6). Significantly higher parasite burdens were recorded in the lungs and eyes of mice infected with ToxoDB genotypes #13 and #6. Genotyping of ROP loci revealed that the virulent Caribbean isolates had a different ROP18/ROP5 allelic profile (3/1) to the virulent Brazilian isolate (1/3); however, the avirulent Caribbean isolate (ToxoDB genotype #1) had the same ROP18/ROP5 profile as the avirulent European isolate (ToxoDB #3) (both 2/2). Caribbean isolates of intermediate virulence (ToxoDB #141 and #265) all had the same ROP18/ROP5 allelic profile (2/2). CONCLUSIONS: Isolates from the Caribbean with ToxoDB genotype #13 were acutely virulent for mice and comparable to a known virulent Brazilian isolate. The ROP protein allelic profile of the virulent Caribbean and Brazilian isolates differed indicating that perhaps other factors are involved in predicting virulence. Understanding virulence is important for predicting disease outcome in humans and may also aid vaccine design as well as drug discovery.
Assuntos
Proteínas de Protozoários/genética , Toxoplasma/patogenicidade , Toxoplasmose/parasitologia , Alelos , Animais , Brasil , Região do Caribe , Europa (Continente) , Feminino , Genótipo , Humanos , Camundongos , Proteínas Serina-Treonina Quinases/genética , Toxoplasma/genética , VirulênciaRESUMO
The aim of the present study was to detect Toxoplasma gondii DNA in raw milk samples of goats and sheep of local breeds from the semi-arid region of the states of Pernambuco and Paraíba, Northeastern Brazil. Serum and milk samples were collected from 243 animals (186 goats and 57 sheep). The Indirect fluorescent antibody test (IFAT) was used to search for anti-T. gondii IgG antibodies with a cutoff of 64. Subsequently, the raw milk samples were subjected to DNA extraction and PCR to detect DNA of T. gondii. The IFAT results showed a 6.58% (16/243) positivity when all the samples were considered and a positivity of 15.78% (9/57) and 3.76% (7/186) for goats and sheep samples, respectively. The PCR assay detected T. gondii DNA in 2.06% (5/243) of all the samples tested. All the PCR positive samples were from goats. This result shows the importance of adopting measures of flock's sanitary management and avoiding the consumption of raw milk may constitute a potential risk to the health of milk consumers in this region.