Viral, Fungal & Parasitic Infections MCQ

Viruses and fungi produce a large share of the lesions on the oral mucosa, and several carry infection-control or cancer implications that matter at the chair. The dental jobs here are to recognize the common viral lesions (herpes, zoster, the enteroviral rashes), to spot the oral signs of HIV, to know that HPV is now a leading cause of oropharyngeal cancer, to protect everyone from the bloodborne viruses (hepatitis B and C, HIV) with standard precautions, and to recognize the dangerous fungal infections that strike the immunocompromised, above all mucormycosis.

The Herpesviruses

• Primary HSV-1 infection in a child is herpetic gingivostomatitis: fever, malaise, and crops of painful vesicles and ulcers throughout the mouth (including attached gingiva), often with refusal to eat or drink.
• After the primary infection, HSV-1 lies latent in the trigeminal ganglion. Reactivation (sun, stress, illness) gives recurrent herpes labialis (cold sores), preceded by a tingling prodrome, at the vermilion border of the lip.
• Active herpetic lesions are contagious. Herpetic whitlow is an HSV infection of a finger, a recognized occupational risk that is part of why gloves are mandatory; defer elective treatment when active perioral lesions are present.
• Varicella-zoster virus causes chickenpox (primary) and, on reactivation, shingles (herpes zoster): a painful, unilateral, dermatomal vesicular eruption that can follow a trigeminal branch and involve the oral mucosa, sometimes leaving postherpetic neuralgia. EBV causes mononucleosis and oral hairy leukoplakia, and HHV-8 causes Kaposi sarcoma.

Other Oral Viruses: Coxsackie and HPV

• Coxsackievirus (an enterovirus) causes herpangina, with vesicles and ulcers on the soft palate and posterior oropharynx, and hand-foot-and-mouth disease, with oral ulcers plus a rash on the hands and feet, both common and self-limited in young children.
• Human papillomavirus causes benign oral lesions (squamous papilloma, verruca, condyloma) and, importantly, the high-risk types 16 and 18 are a rising cause of oropharyngeal squamous cell carcinoma, classically at the base of the tongue and tonsils.
• HPV-related oropharyngeal cancer is increasing, particularly in younger patients without the traditional heavy tobacco and alcohol history, and may present as a painless neck lump (a metastatic node).
• The HPV vaccine protects against the high-risk oncogenic types and is a genuine cancer-prevention tool worth discussing with appropriate patients.

Bloodborne Viruses: Hepatitis and HIV

• Hepatitis B and hepatitis C are bloodborne viruses of major occupational concern in dentistry. Hepatitis B is highly transmissible but vaccine-preventable, and hepatitis B vaccination is recommended for dental personnel; hepatitis C has no vaccine. Hepatitis A, by contrast, is spread by the fecal-oral route.
• HIV is transmitted by blood and body fluids (not by casual contact). As CD4 counts fall, opportunistic infections appear, and the mouth is often where the first signs show.
• Oral manifestations that should prompt thinking about HIV include pseudomembranous candidiasis, oral hairy leukoplakia (EBV-driven, non-wipeable, on the lateral tongue), Kaposi sarcoma (a purplish lesion, often on the palate), and severe periodontal disease such as linear gingival erythema or necrotizing periodontitis.
• After a percutaneous exposure (needlestick), the steps are to wash the area, report immediately, and seek occupational evaluation for postexposure assessment; this is exactly why standard precautions and safe sharps handling exist.

Fungal Infections: From Candida to the Deep Mycoses

• Candida albicans is an opportunistic fungus and the most common oral fungal infection; candidiasis (thrush, denture stomatitis, angular cheilitis) is a signal to look for a cause such as antibiotics, steroids, dentures, dry mouth, diabetes, or immunosuppression.
• Mucormycosis (zygomycosis) is a rare but devastating angioinvasive fungal infection seen in diabetic ketoacidosis and the immunocompromised; it can present as palatal necrosis or a black eschar with facial pain and swelling and is a surgical emergency.
• Histoplasmosis and other deep mycoses can produce a chronic oral ulcer that mimics malignancy, particularly in endemic regions or immunocompromised patients, so biopsy and culture matter.
• Recognizing a necrotic palatal lesion in a poorly controlled diabetic, or a chronic non-healing oral ulcer, as a possible deep fungal infection (and referring urgently) is the dentist's key fungal-infection skill beyond everyday candidiasis.

Parasites: A Brief Note

• Oral parasitic disease is uncommon in routine practice, but parasites matter in specific contexts.
• Toxoplasma gondii can reactivate in advanced HIV or other severe immunosuppression, typically causing brain (not oral) disease, and is part of the opportunistic picture in immunocompromised patients.
• Leishmania can cause mucosal (including oral and nasal) ulceration in endemic regions and in travelers, an occasional cause of a chronic oral ulcer to keep in the differential.
• The practical point is to keep parasitic causes in mind for a chronic oral lesion in a patient who is immunocompromised or has relevant travel or residence history, and to refer for diagnosis.