Diagnostic Methods, Results and Discussion of Neurological Defects and Death Caused by Human Boca Virus and Respiratory Tract Reactivations or Reinfections in Two Adults

Although it is rare, particularly in adults, human bocavirus 1 (HBoV1) of the Parvoviridae family causes mild fatal respiratory tract infections in young children due to broad immunity. Although they are uncommon, HBoV1 reinfections or reactivations that cause casualties may go undiagnosed. We report uncommon diagnostic features of HBoV1 respiratory tract infection in two young adults, one immunosuppressed and the other previously healthy. In respiratory samples from both patients, HBoV1 DNA loads were extremely high. Although the immunocompromised patient had previously shown HBoV1-specific high-avidity IgG and weak IgM positivity nine months prior to the respiratory symptoms, the patient was also HBoV1 DNA-positive in blood, stool, and a colon sample. Similar to the previously healthy patient, the CSF fluid showed a sero conversion associated with HBoV1 IgG of high avidity and very weak IgM in serum, indicating preexisting immunity. Additionally, this patient showed high HBoV2 cross-reactivity. Given their ages and the molecular and serological findings, it is suggested that both patients had aberrant HBoV1 reinfection or reactivation, which led to neurological impairments and mortality.