Treatment of Platynosomiasis in Callitrichids using the Biotherapeutic Platynosomum sp. 30cH and Ultrasound Monitoring

Background: Platynosomum sp. infection in non-human primates (NHPs) leads to a chronic and progressive disease that affects the bile ducts and liver, often resulting in death. Diagnosis is challenging due to nonspecific clinical signs, making ultrasonography an essential diagnostic tool to detect hepatic parenchyma and bile duct alterations caused by parasitism. The severity of lesions is believed to be associated with the duration of the infection and the parasitic load. The aim was to evaluate the effectiveness of the medicine Platynosomum sp. 30cH in treating platynosomiasis in Callithrix spp. , monitored through ultrasonographic imaging. Methods: Thirty-six Callithrix spp. individuals under human care were selected based on ultrasonographic findings suggestive of biliary system parasitism, with or without associated hepatic lesions. Ethical approval was obtained from CEUA (no. 57/2021) and SISBIO (No.78874–1). The ultrasonographic examinations were performed using a Logic E device (GE HealthCare, United States) equipped with a linear 10 to 22 MHz probe. Animals were positioned supine after a 4-hour fasting period, and anesthesia was induced with isoflurane. Parameters assessed included the size, shape, echotexture, and echogenicity of the liver; size, content, and wall thickness of the gallbladder; and bile duct characteristics. The biotherapeutic was administered daily (10 globules/1 L of drinking water). Serial ultrasonographic examinations were conducted at 30, 60, and 90 days to classify the severity of parasitism. Results: After 30 days, 24 of 36 individuals had biliary alterations: 13 absent, 18 mild, 1 moderate, and 4 severe. At 60 days, one animal died of natural causes; among 35 individuals, 15 had alterations: 20 absent, 7 mild, 1 moderate, and 8 severe. By 90 days, 11 of 35 individuals exhibited alterations: 24 absent, 7 mild, 1 moderate, and 3 severe. Hepatic lesions remained stable, except for one animal, which progressed to fibrosis. Conclusions: The Platynosomum sp. 30cH showed effectiveness in managing platynosomiasis in NHPs, as demonstrated by ultrasonographic monitoring.