Tina Mikuletič, Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana

Tina Mikuletič1, Gašper Markelj2,3, Marko Kolenc1, Simona Ivančan2,4, Irena Šest1, Mojca Rožič2,5, Maruša Debeljak2,6, Tina Triglav1,2 1 Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia 2 Faculty of Medicine, University of Ljubljana, Vrazov Trg 2, 1000 Ljubljana, Slovenia 3 Department of Allergology, Rheumatology and Clinical Immunology, University Children's Hospital, University Medical Center Ljubljana (UMC), 1000 Ljubljana, Slovenia 4 Department of Haematology and Oncology, University Children's Hospital, University Medical Centre Ljubljana (UMC), 1000 Ljubljana, Slovenia 5 Department of Infectious Diseases, University Medical Centre Ljubljana (UMC), 1000 Ljubljana, Slovenia 6 Institute of Special Laboratory Diagnostic, University Children's Hospital, University Medical Centre Ljubljana (UMC), 1000 Ljubljana, Slovenia

Epidemiology, Evolution, and Diversity

A 1-month-old male infant was admitted due to inappetence and weight loss. Symptoms resolved in a few days with supportive therapy. Rotavirus was detected in a stool sample using syndrome-based multiplex real-time RT-PCR. Due to his clinical features, Chediak-Higashi syndrome was suspected and genetically confirmed. Stool sample remained rotavirus-positive one week later without clinical symptoms. He remained asymptomatic on prophylactic therapy with polyclonal immunoglobulins, control stool sample at 3 months of age was negative for rotavirus and other common gastrointestinal pathogens. At 5 months of age, the child tested positive for rotavirus again with mild gastrointestinal symptoms during conditioning for haematopoietic stem cell transplantation (HSCT). He remained mildly symptomatic in first few weeks with successful myeloid engraftment 3 weeks post HSCT. Later, severe stool loss developed with occasional vomiting, without systemic features. Several control stool samples were sent to the laboratory at 7-14 day intervals, all of which tested positive for rotavirus only, with low ct values indicating a high viral load. In addition, rotavirus particles were observed in all control stool samples under transmission electron microscopy, indicating that the infectious viruses were still actively replicating. In the absence of other Graft-versus-host disease features, immunosuppressive therapy was slowly decreased. Stool loss improved with the introduction of nitazoxanide and with first signs of cellular immunity reconstitution.
The rotavirus genotype was determined in the first seven stool samples. Preliminary results indicate the presence of G3P[8] genotype in all tested samples, with the first two samples possibly indicating a mixed genotype.