Infectious Diseases
Infectious diseases remain a significant health burden in the UAE despite the country’s advanced healthcare infrastructure. The UAE’s position as a global travel and business hub, its large expatriate workforce from endemic regions, and its climate create unique infectious disease challenges. Common conditions include tuberculosis (particularly among migrant workers from South and Southeast Asia), viral hepatitis, gastrointestinal infections, and emerging threats like MERS-CoV. The DOH (UAE) examination tests your knowledge of common infectious diseases, their transmission, clinical presentation, treatment, and crucially — the infection prevention measures that protect both patients and healthcare workers.
🟢 Lite — Quick Review (1h–1d)
Rapid summary for last-minute revision before your exam.
Key Infectious Diseases in UAE — Quick Reference:
| Disease | Transmission | Key Features | Treatment |
|---|---|---|---|
| Tuberculosis | Airborne | Chronic cough >3 wks, night sweats, weight loss, haemoptysis | RIPE (Rifampicin, Isoniazid, Pyrazinamide, Ethambutol) |
| Hepatitis B | Blood, sexual | Jaundice, fatigue, dark urine; chronic → cirrhosis | Antivirals (entecavir, tenofovir) |
| Hepatitis C | Blood | Often asymptomatic initially; chronic liver disease | Direct-acting antivirals (DAAs) |
| HIV/AIDS | Blood, sexual, perinatal | Opportunistic infections; weight loss; lymphadenopathy | ART (antiretroviral therapy) |
| Dengue | Mosquito (Aedes) | Fever, severe headache, retro-orbital pain, rash | Supportive care |
| MERS-CoV | Droplet/contact | Severe pneumonia; high mortality; camel exposure | Supportive; ribavirin + interferon (controversial) |
| Typhoid | Food/water | Stepwise fever, rose spots, hepatosplenomegaly | Ceftriaxone, azithromycin |
Standard and Transmission-Based Precautions — Know Which to Apply:
- Standard precautions for ALL patients (hand hygiene, PPE based on risk, sharps safety)
- Contact precautions: MRSA, VRE, C. difficile, norovirus, scabies
- Droplet precautions: Influenza, COVID-19, pertussis, meningococcus, mumps, rubella
- Airborne precautions: TB, measles, varicella, disseminated zoster
⚡ Exam Tip: When a patient with confirmed or suspected TB is admitted to a UAE hospital, they must be placed in an Airborne Infection Isolation Room (AIIR — negative pressure room). Staff entering the room must wear an N95 respirator (fit-tested), gown, and gloves. The door must remain closed at all times.
🟡 Standard — Regular Study (2d–2mo)
Standard content for students with a few days to months.
1. Tuberculosis — A Persistent Threat
TB Epidemiology in UAE:
- UAE has low overall TB incidence, but cases among migrant workers (especially from India, Pakistan, Bangladesh, Philippines) are higher
- Active TB screening is mandatory for residency visa applicants in the UAE
- Latent TB infection (LTBI) is common in migrant populations
Active TB Diagnosis:
- Symptoms: Chronic cough (>3 weeks), haemoptysis, night sweats, fever, weight loss, anorexia
- Chest X-ray: Upper lobe cavitation, hilar lymphadenopathy
- Sputum smear microscopy: Acid-fast bacilli (AFB) — requires 3 consecutive early morning samples
- GeneXpert MTB/RIF: Rapid molecular test; also detects rifampicin resistance
- Culture: Gold standard; takes 2–6 weeks; allows full sensitivity testing
TB Treatment — Standard Regimen (RIPE):
- Rifampicin (R): Red/orange body fluids; hepatotoxic; induces CYP450 (many drug interactions)
- Isoniazid (I): Hepatotoxic; peripheral neuropathy (prevent with pyridoxine/vitamin B6); drug-induced lupus
- Pyrazinamide (P): Hepatotoxic; hyperuricaemia (gout)
- Ethambutol (E): Optic neuritis (red-green colour blindness — check vision before starting)
- Duration: 6 months (2 months intensive phase with all 4; 4 months continuation phase with rifampicin + isoniazid)
Drug-Resistant TB:
- MDR-TB: Resistant to R and I — requires longer, more toxic regimens (fluoroquinolones, injectables)
- XDR-TB: Resistant to R, I, fluoroquinolones, and injectables — very limited treatment options
- DOT (Directly Observed Therapy) is mandatory in UAE for all TB patients
Infection Control for TB:
- AIIR (negative pressure) isolation
- N95 respirators for staff
- Patient wears surgical mask when outside the room
- Ultraviolet germicidal irradiation (UVGI) in some facilities
- Visitors minimised; must wear N95
2. Viral Hepatitis
Hepatitis B:
- Transmission: Blood, sexual contact, perinatal (mother to child)
- Incubation: 6 weeks to 6 months
- Acute: Jaundice, fatigue, anorexia, nausea, right upper quadrant pain; most adults recover fully
- Chronic infection (>6 months): Develops in ~5% of adults; risk of cirrhosis and hepatocellular carcinoma
- Prevention: Hepatitis B vaccine (part of UAE national immunisation schedule); HBIG for needle-stick exposure
- Treatment: Oral antivirals (entecavir, tenofovir) — suppress but rarely cure; lifelong therapy often needed
Hepatitis C:
- Transmission: Primarily blood (IV drug use, contaminated medical equipment, tattooing)
- Incubation: 2 weeks to 6 months
- Often asymptomatic; 15–30% spontaneously clear; 70–85% develop chronic infection
- Chronic: Slow progression to cirrhosis (20–30% over 20–30 years)
- Diagnosis: Anti-HCV antibodies → HCV RNA PCR to confirm
- Treatment: Direct-acting antivirals (DAAs) — sofosbuvir/ledipasvir, glecaprevir/pibrentasvir — cure rates >95% in 8–12 weeks with minimal side effects
Hepatitis A and E:
- Fecal-oral transmission (contaminated food/water)
- Self-limiting in healthy individuals
- Hepatitis E: Particularly dangerous in pregnant women (fulminant hepatic failure)
3. HIV/AIDS in the UAE
Epidemiology:
- Low prevalence in UAE general population
- Mandatory screening for residency visa applicants
- Key affected populations: MSM, sex workers, people who inject drugs
Transmission:
- Unprotected sexual intercourse (most common)
- Blood and blood products (now rare with screening)
- Vertical (mother to child) — preventable with ART
- IV drug use (shared needles)
Opportunistic Infections — Key Ones:
| Infection | CD4 Count | Presentation | Treatment |
|---|---|---|---|
| Pneumocystis jirovecii pneumonia (PJP) | <200 | Subacute dyspnoea, non-productive cough, hypoxaemia | Trimethoprim-sulfamethoxazole (TMP-SMX) |
| Oesophageal candidiasis | <200 | Odynophagia, white oral plaques | Fluconazole |
| Toxoplasmosis | <100 | Headache, confusion, focal neurological deficits | Pyrimethamine + sulfadiazine |
| Cryptococcal meningitis | <100 | Headache, fever, meningism | Amphotericin + flucytosine |
UAE Context:
- ART is freely available to HIV-positive individuals in UAE
- Discrimination against PLHIV is illegal; confidentiality is paramount
- PrEP (pre-exposure prophylaxis) available for high-risk individuals
- PEP (post-exposure prophylaxis): Available for healthcare workers (occupational) and general population (non-occupational) after high-risk exposure
🔴 Extended — Deep Study (3m+)
Comprehensive coverage for students on a longer study timeline.
4. Antibiotic Resistance — A UAE and Global Priority
Key Resistant Organisms in UAE:
| Organism | Resistant to | Implications |
|---|---|---|
| MRSA | Methicillin (and most beta-lactams) | Contact precautions; vancomycin or linezolid |
| ESBL producers | Cephalosporins, penicillins | Carbapenems |
| CRE | Carbapenems | Very limited options; colistin, tigecycline, ceftazidime-avibactam |
| VRE | Vancomycin | Linezolid, daptomycin |
| C. difficile | Fluoroquinolones, clindamycin (trigger) | Metronidazole or vancomycin (oral); stop offending antibiotic |
Antibiotic Stewardship:
- All UAE hospitals have Antimicrobial Stewardship Programmes (ASPs)
- Key elements: Formulary restriction, pre-authorisation, de-escalation based on culture results, IV to oral conversion, automatic stop dates
5. Food-Borne and Water-Borne Diseases
Cholera:
- Vibrio cholerae; contaminated water/seafood
- Profuse watery “rice-water” diarrhoea; rapid dehydration; can be fatal without treatment
- Treatment: ORS (oral rehydration solution) or IV fluids; doxycycline or azithromycin
Salmonella (Non-typhoidal):
- Poultry, eggs; self-limiting gastroenteritis
- Treatment: Supportive; antibiotics only in severe cases or immunocompromised
Typhoid Fever (Salmonella typhi):
- Endemic in South Asia; import cases in UAE
- Stepwise fever, rose spots (trunk), relative bradycardia, splenomegaly
- Diagnosis: Blood culture (most sensitive), Widal test (less reliable)
- Treatment: Ceftriaxone or azithromycin
6. Parasitic Diseases
Malaria (in returning travellers):
- Plasmodium falciparum (most dangerous), P. vivax, P. ovale, P. malariae
- Fever pattern: P. vivax/ovale = tertian (every 48h); P. malariae = quartan (every 72h); P. falciparum = irregular
- P. falciparum: Can cause cerebral malaria, renal failure, severe anaemia — medical emergency
- Treatment: Artemether-lumefantrine (uncomplicated); IV artesunate (severe/critical)
- UAE: No local malaria transmission; all cases are imported
Leishmaniasis:
- Sandfly bite; endemic in Middle East
- Cutaneous: Skin ulcers (oriental sore)
- Visceral (Kala-azar): Fever, hepatosplenomegaly, pancytopenia — requires pentavalent antimonials
Exam Watch: A returning traveller from a malaria-endemic country who presents with fever and flu-like symptoms should be tested for malaria with thick and thin blood smears. In a critically ill patient, do not wait for results — start empirical antimalarial treatment if malaria is strongly suspected. In the UAE, notify the Dubai Health Authority (DHA) or relevant public health authority for all suspected notifiable infectious diseases.
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