Pediatric Amazonian Toxoplasmosis Caused by Atypical Strains in French Guiana, 2002-2017

Amazonian toxoplasmosis is a recently described form of Toxoplasma gondii infection, characterized by severe clinical and biological features and involvement of atypical genetic strains circulating through a forest-based cycle. Though mostly reported in French Guiana since 1998, this disease is probably under-diagnosed in other areas of South America. Few data are available on its specific features in children.

We retrospectively included all children seen in Cayenne between 2002 and 2017, diagnosed with acute toxoplasmosis due to an atypical strain. Clinical and biological features and risk factors of Amazonian toxoplasmosis were recorded.

Eleven children met the inclusion criteria. The main clinical features were fever, lymphadenopathy, hepatomegaly and splenomegaly, as reported in adults. Less expected signs such as rhinorrhea, pharyngitis and maculopapular rash were also frequent. Cutaneous signs were associated with the involvement of a genetically atypical strain. Respiratory involvement was rare but associated with respiratory distress. Outcome was always favorable. Treatment by pyrimethamine/sulfadiazine or trimethoprim/sulfamethoxazole was always justified, efficient and well tolerated. Genetic analysis suggested the involvement of wild mammals in disease transmission, and strain-dependent virulence as one of the prognostic risk factors.

As in adults, pediatric Amazonian toxoplasmosis requires a systematic treatment. Symptoms such as skin rash, rhinorrhea and pharyngitis should not be mistaken for viral infections, when associated with lymphadenopathy or fever. Pediatricians working in South America should be familiar with these clinical presentations and with the different risk factors of Amazonian toxoplasmosis.