Clinical and epidemiological investigation of human infection with zoonotic parasite Trypanosoma dionisii in China.

Background: Trypanosomiasis continues to pose a global threat to human health, with human infection mainly caused by Trypanosoma brucei and Trypanosoma cruzi.

Methods: We present a 30-year-old pregnant woman with persistent high fever from Shandong Province, China. High-throughput sequencing revealed the presence of Trypanosoma dionisii in blood. We conducted an analysis of the patient's clinical, epidemiological, and virological data.

Results: The patients exhibited fever, shortness of breath, chest tightness, accompanied by change in liver function and inflammatory response. She made a full recovery without any long-term effects. T. dionisii was detected in blood collected 23 days after onset of illness. The 18S rRNA gene sequence showed close similarity to T. dionisii found in bats from Japan, while the gGAPDH gene was closely related to T. dionisii from bats in Mengyin County, Shandong Province. Phylogenetic analysis demonstrated the current T. dionisii belongs to clade B within its species group. Positive anti-Trypanosoma IgG antibody was detected from the patient on Day 23, 66 and 122 after disease onset, as well as the cord blood and serum from the newborn. Retrospective screening of wild small mammals captured from Shandong Province revealed a prevalence rate of 0.54% (7/1304) for T. dionisii; specifically among 0.81% (5/620) of Apodemus agrarius, and 0.46% (2/438) of Mus musculus.

Conclusions: The confirmation of human infection with T. dionisii underscores its potential as a zoonotic pathogen, while the widespread presence of this parasite in rodent and bat species emphasizes the emerging threat it poses to human health.