Toxoplasmosis in a free-ranging hairy dwarf porcupine (Sphiggurus spinosus) with a potential novel genotype.

Abstract

Toxoplasmosis is a zoonotic disease caused by the ubiquitous coccidia Toxoplasma gondii. Rodents play an important role in maintaining its life cycle, as they are one of the main diet sources for felids (wild and domestic), the unique definitive hosts. However, reports of toxoplasmosis in porcupines (Order Rodentia) are uncommon, with gaps concerning its pathophysiology. South America is the continent with the greatest genetic diversity of rodents and T. gondii. A free-ranging hairy dwarf porcupine was admitted to a wildlife rescue centre with a history of trauma. During rehabilitation, the animal presented neurological symptoms (sporadic episodes of hind limbs paresis) and died 5 months later. The main findings during necropsy were brain congestion and severe incisor overgrowth associated with maxillary perforation. The histopathological exam showed moderate encephalitis, with variable-sized round cysts, positive for PAS stain and immunohistochemistry for T. gondii. Additionally, two cysts were observed in the medulla of the adrenal gland. Molecular techniques were performed to characterize the parasite load by qPCR (Cq = 30) and the genotype by PCR-RFLP with 11 markers, which revealed a potential new genotype. This case adds to the body of knowledge in comparative pathology of Neotropical Rodentia and reports a new potential genotype circulating in South America.