Immunohistochemical and serological aspects of Toxoplasma gondii infection in Neotropical primates

Abstract

Toxoplasmosis, a disease caused by the intracellular coccidian Toxoplasma gondii that infects most warm-blooded vertebrates, is widely distributed and fatal for primates, which are peculiarly susceptible for unknown reason(s). Owing to the increasing number of Neotropical mammal deaths where in T. gondii were detected in analyzed tissues, the present immunohistochemical study analyzed the distribution patterns of immunostainings related to this parasite on primates necropsied at the Laboratório de Patologia Animal of Universidade de Passo Fundo (UPF), between the years of 2000 and 2014. Furthermore, a serological survey for the disease was conducted for 21 primates from the UPF Zoo, Rio Grande do Sul, Brazil, belonging to genera Sapajus and Alouatta. In a immunohistochemical test performed using streptavidin-biotin-peroxidase, 26.53% positivity was detected in 98 primates. Immunostainings revealed that infection differed among the lung (76.92%), liver (58.33%), heart (50%), brain (42.30%), and kidney (23.07%) tissues. Serology performed through indirect hemagglutination showed reactivity in 85.7% of the animals, all belonging to Sapajus sp., while the three primates that did not show reactivity (14.3%) belonged to Alouatta sp.

Pathology and epidemiology of fatal toxoplasmosis in free-ranging marmosets (Callithrix spp.) from the Brazilian atlantic forest

“…Pathological findings of fatal toxoplasmosis in this study were characterized by a multifocal random necrotizing hepatitis, associated with random lipidosis; interstitial pneumonia rich in alveolar foamy macrophages and fibrin deposition; necrotizing myocarditis; and necrotizing splenitis. These findings are compatible with lesions previously described in cases of NWP lethal infections [1][2][3][4][5][6]14]. Necrotizing lesions are an important feature in T. gondii infection and are caused by the direct rupture of the cells by the tachyzoite forms during replication and exit from the host cell, leading to cell death and necrosis surrounded by an acute inflammatory response [15].…”

“…YF in susceptible NWP is characterized by a midzonal to massive necrotizing hepatitis with coagulative necrosis, scarce inflammatory cells, and apoptotic hepatocytes, which are traditionally called Councilman-Rocha Lima bodies [23][24][25][26]. Animals infected with toxoplasmosis, usually develop a multifocal random necrotizing hepatitis with lytic necrosis, variable inflammatory infiltrate and intralesional zoites, as was observed in our cases [1][2][3][4][5][6]. Importantly, in agreement with histopathological findings, no infected marmoset from this study was co-infected with YFV, based on negative RT-qPCR and IHC testing for YFV performed at the official diagnostic laboratory.…”

“…Neotropical primates (New World Primates; NWP) are highly susceptible to toxoplasmosis [1][2][3]. In captive NWP, toxoplasmosis is characterized by a hyperacute to acute, systemic disease with difficult treatment approach, that evolves quickly to death, being sometimes associated with outbreaks with high lethality [1][2][3][4][5][6][7]. There are differences in susceptibility between NWP species, with capuchins being considered more resistant than other neotropical species [2,6].…”

Infectious diseases of neotropical primates

“…Pathological findings are represented by random necrotizing lesions in many organs (Fig. 8), especially at liver, lungs, spleen, and brain, associated with intralesional tachyzoites, that are better observed by IHC (71,116,155,177,183). Another important feature of the T. gondii infection in NWP is the severe pulmonary edema and hemorrhage, in some cases associated with diffuse alveolar damage, characterized by alveolar hyaline membrane (144,177).…”