Case Report: Visceral Leishmaniasis Falsely Diagnosed as Viral Hepatitis C Without Febrile Symptoms.

Background: Visceral leishmaniasis (VL), also known as kala-azar, is caused by an intracellular parasite transmitted to humans by the bite of a sand fly, and with the source of the infection mainly being dogs. The main features of the disease are irregular fever, weight loss, hepatosplenomegaly and anaemia. Diagnosis relies mainly on bone marrow aspiration tests to find Leishman-Donovan(LD) bodies. And we report the case without febrile symptoms and hepatitis C virus antibody was probably false positive.

Case Presentation: The case was a 74-year-old male residing in Yangquan City, Shanxi Province, a VL endemic area. He presented with generalised malaise, hepatosplenomegaly and scarring pigmentation on the skin as a result of scratching. Laboratory tests showed pancytopenia, positive hepatitis C virus antibody (HCV-Ab), positive direct anti-human globulin test (DAT), positive anti-cardiolipin antibody IgG, IgM (+), and increased immunoglobulin IgG. Symptomatic treatments such as hepatoprotection and blood transfusion were given, but the patient's symptoms still persisted and his spleen and liver further enlarged. Further repeat tests were performed and found to be negative for hepatitis C virus antibodies and antigens. The patient was eventually found to be infected with by rk39 rapid diagnostic test and metagenomic next-generation sequencing(mNGS). And the patient quickly relieved after one course of treatment with sodium stibogluconate.

Conclusion: Patients with VL may cause abnormalities in the immune system, leading to false positives for various antibodies without clear febrile symptoms, resulting in misdiagnosis or delayed diagnosis. It is important to consider VL in cases where there is a significant hepatosplenomegaly with a relevant epidemiological history. If the diagnosis cannot be confirmed through bone marrow aspiration and the patient is not suitable for splenic aspiration, the rk39 test can be used for initial exclusion and further verified through mNGS.