Enteric Fever (Typhoid/Paratyphoid) ✅

Humans are the only hosts of these pathogens, which spread person-to-person or via contaminated food and water. Paratyphoid fever is milder than typhoid fever. Salmonella typhi has an incubation period of 14 to 21 days. 30% of the cases become chronic carriers due to persistent gallbladder infection.In the UK, most typhoid/paratyphoid cases are imported after travel, especially from South Asia. 🧠 Diagnosis rule: Fever after travel + compatible symptoms = think enteric fever. Confirm with blood culture; use stool culture mainly for later diagnosis, carriage and public health clearance.

🌡️ About

• Enteric fever is the umbrella term for typhoid fever and paratyphoid fever.
• Typhoid fever: caused by Salmonella enterica serovar Typhi.
• Paratyphoid fever: caused by Salmonella enterica serovars Paratyphi A, B or C.
• It is a systemic infection and may be life-threatening without prompt antibiotic treatment.

🦠 Aetiology

• Transmission: Faeco-oral (contaminated food/water).
• Children aged 1–5 yrs particularly vulnerable.
• Gallbladder = reservoir in chronic carriers.
• Pathology: Peyer’s patches in ileum → swelling, ulceration → intestinal bleeding/perforation in severe cases.

🔬 Key Microbiology

• Gram-negative, motile, facultative anaerobic rod.
• Non-lactose fermenter → pale colonies on MacConkey agar.
• Oxidase-negative and catalase-positive.
• Survives exposure to bile; chronic carriage may occur in the biliary tract.

🩺 Clinical Presentation

• Incubation:variable 7–14 days (typhoid); shorter in paratyphoid.
• Week 1: Dry cough, malaise, headache, stepwise fever (> 38°C for 3 days), constipation/diarrhoea, relative bradycardia 🚨.
• Week 2: Rose spots (trunk), splenomegaly, hepatomegaly, lymphadenopathy, epistaxis, persistent bradycardia.
• Week 3: Complications – bowel haemorrhage, perforation, toxaemia, cholecystitis, osteomyelitis (esp. sickle cell), myocarditis, nephritis, meningitis, pneumonia.
• Week 4: Recovery (if untreated), but some → prolonged illness or carrier state.
• Paratyphoid: Shorter, milder, rash more prominent, intestinal complications less common.

⚠️ Clinical clue: Relative bradycardia + low WCC despite fever. 🧒 Sickle cell children → high risk of Salmonella osteomyelitis.

🧪 Investigations

• FBC: Low WCC, raised AST/ALT.
• Blood cultures: Before antibiotics. Positive in 1st–2nd week.
• Stool cultures: Positive from 2nd week onward.
• Urine cultures: May also be positive.
• Widal test: Obsolete/unreliable.

⚠️ Clinical clue: Fever after travel to an endemic area + abdominal symptoms ± relative bradycardia should trigger consideration of enteric fever. 🧒 Children with sickle cell disease are at increased risk of Salmonella osteomyelitis.

💊 Management: Involve ID early for contact tracing

• Initial approach: assess severity, hydrate, correct electrolyte disturbance, culture blood and stool and urine.
• Infection control: strict hand hygiene, enteric precautions, local isolation guidance, especially if diarrhoea is present.
• Antibiotics: choice depends on severity, travel origin, pregnancy status, resistance risk and susceptibility results.
• Uncomplicated disease: oral azithromycin or ciprofloxacin may be used, but ciprofloxacin should only be used when susceptibility is likely or confirmed.
• Severe disease, vomiting, complications or inability to tolerate oral therapy: admit and use IV therapy such as ceftriaxone, guided by Microbiology / Infectious Diseases.
• Resistant or XDR typhoid risk: specialist advice is essential; treatment may require alternative IV therapy depending on susceptibility and travel history.
• Chronic carriage: manage with specialist and public health input; prolonged antibiotics may be required and biliary disease/gallstones should be considered.
• Public health: typhoid and paratyphoid are notifiable diseases. Notify UKHSA Health Protection Team. Public health follow-up/contact risk assessment,
• Food handlers and other risk groups: exclusion and clearance testing should be directed by the Health Protection Team. Where clearance is required, this usually involves 3 negative faecal samples starting at least 1 week after completing antibiotics and taken at least 48 hours apart.

🧠 UK antibiotic rule of thumb: Uncomplicated = oral azithromycin 1 g PO stat, then 500 mg PO once daily to complete a 7-day total course. Complicated / vomiting / septic = IV ceftriaxone 2g OD IV initially then switch Azithromycin unless XDR risk. XDR risk and severe = meropenem + azithromycin . Ciprofloxacin = only if susceptibility confirmed Ciprofloxacin 500 mg PO BD for 7 days may be used.. Avoid ciprofloxacin in pregnancy

🛡️ Prevention

• Check destination-specific advice using NaTHNaC / TravelHealthPro before travel.
• Vaccination is recommended for travellers to some endemic areas, but it is not fully protective.
• Available UK vaccine options include injectable Vi polysaccharide vaccine and live oral Ty21a vaccine.
• Safe food, clean water and strict hand hygiene remain essential.