Research Article
Volume 16 Issue 8 - 2020
Characterization of the Virulence of three Chronic Strains of Toxoplasma gondii according to Survival, Histopathology Detection Studies
María A Vethencourt1*, Misael Chinchilla1, Idalia Valerio1,2, Jose E Bolaños1, Cristal López2, Gloriana Loaiza2, Laura Valerio1 and Jimmy Ramírez1
1Basic Research Laboratory, University of Medical Sciences, San Jose, Costa Rica
2Faculty of Microbiology, University of Medical Sciences, San Jose, Costa Rica
*Corresponding Author: María A Vethencourt, Basic Research Laboratory, University of Medical Sciences, San Jose, Costa Rica.
Received: June 15, 2020; Published: July 17, 2020


The objective of this work is to characterize the virulence of three chronic Toxoplasma gondii strains, isolated in Costa Rica and characterized molecularly by PCR-RFLP previously, according to survival and histopathology in tissues of Swiss CD-1 mice. Ten (10) mice (5 female and 5 male) were infected orally with serial dilutions of brain tissue cysts from previously infected mice. Three chronic strains of T. gondii, previously molecularly characterized, came from the domestic cat (Felis catus, TFC-1; A), to "caucel" (popular name) (Leopardus wiedii, TLW-1; B) and from white mice, (Bos taurus, TBT-1;D) fed beef. Mice were euthanized on day 30 of the experiment. Virulence based on survival was recorded and the organs of the mice were histologically studied. The fixed tissues were processed by routine methods and stained with Harry's hematoxylin-eosin (H and E). The areas of consolidation (CA), the presence of tachyzoites (Tq) or tissue cysts (Q) were estimated by mm3 of tissue analyzed. Strain D, characterized as a variant of Type I, was the most virulent. Strain A, less virulent, characterized as a type I variant, but different from strain D, was the one that manifested a greater number of cysts in the brain in the lowest dilution of the inoculum, despite having manifested a very high tissue inflammatory response in the lung, observed by a higher proportion of AC/mm3 and Tq/mm3 present in this tissue. The highest mortality was observed in female mice compared to males infected with any of the analyzed chronic strains, in the most concentrated infectious doses. So, considering that the responsiveness of the mice in this experiment is the same, the difference lies in the genotype of the chronic strain of T. gondii, on the one hand, and in the dose of the inoculum on the other. The characterization of these strains are necessary for future epidemiological studies in toxoplasmosis.

Keywords: Toxoplasma gondii; Chronic Strains; Virulence; Survival; Histopathology; Costa Rica


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Citation: María A Vethencourt., et al. “Characterization of the Virulence of three Chronic Strains of Toxoplasma gondii according to Survival, Histopathology Detection Studies”. EC Microbiology 16.8 (2020): 28-43.

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