Abstract: Infections of the central nervous system that are caused by more than one organism are on the rise. Dual or triple infections are diagnosed more commonly, and new tests are being developed to target this matter and diagnose multiple coinfection simultaneously.
We present 2 cases of West Nile virus encephalitis, both with a concomitant rickettsial disease (typhus and ehrlichiosis) as well as syphilis in one case and positive serology for St. Louis encephalitis in another. Cross-reactivity with West Nile virus was thought to be the reason for the positivity of the St. Louis virus; but for the other tests, it was felt that they were true positive, as suggested by clinical findings.
Suspicion for these coinfections can help with better diagnosis and management and hopefully reduce morbidity and mortality.