Fungal and viral infections, except superficial or urinary infection with Candida, and endemic parotitis (mumps), are unusual causes of urological symptoms except when the host is immunocompromised or catheterised. Superficial fungal infections are often treated with topical agents whilst invasive disease necessitates treatment with an antifungal drug specific to the mycosis. Candida in the urine is common in hospitalized patients, especially those with diabetes, given antibiotics or catheterised. Viral infections may be transmitted by a variety of routes and managing them often revolves around public health measures including prophylactic vaccination. Acute episodes of viraemia are generally treated with supportive measures and, occasionally specific anti-viral agents. Chronic viral infections, such as Human Immunodeficiency Virus (HIV), may need long-term treatment and some anti-HIV drugs, particularly protease inhibitors, can crystalize out in the urinary tract causing medication-based urolithiasis.