Differential Diagnosis for CNS Infection after Rhesus Macaque Exposure

Single Most Likely Diagnosis

• Herpes B Virus (Macacine Herpesvirus 1): This is the most likely diagnosis due to its prevalence in rhesus macaques and its ability to cause severe CNS infections in humans after exposure, typically through bites or scratches.

Other Likely Diagnoses

• Rabies: Although less common, rabies is a consideration in any animal bite or scratch, including those from rhesus macaques, and can lead to CNS infection if not promptly treated.
• Simian Immunodeficiency Virus (SIV): While SIV itself does not directly cause CNS infections, it can lead to immunosuppression, making the individual more susceptible to opportunistic infections that affect the CNS.

Do Not Miss Diagnoses

• B Virus and Rabies Co-infection: The possibility of co-infection with both B virus and rabies, although rare, is critical not to miss due to the high mortality rate associated with both diseases if left untreated.
• Prion Diseases: Although extremely rare, prion diseases (like Creutzfeldt-Jakob disease) could theoretically be transmitted through exposure to infected tissue, making them crucial not to overlook due to their fatal outcome.

Rare Diagnoses

• Simian Foamy Virus (SFV): SFV can infect humans but is rarely associated with disease. However, its potential to cause CNS symptoms in rare cases makes it a consideration in the differential diagnosis.
• Cercopithecine Herpesvirus 2: Another herpesvirus found in non-human primates, which could potentially cause CNS infections in humans, although such cases are exceedingly rare and not well-documented.