Quail fever (paratyphoid) - Symptoms, Causes, Treatment & Prevention

Overview

Quail fever, also known as paratyphoid or Salmonella Paratyphi infection, is a bacterial illness caused by the Gram‑negative rods Salmonella enterica serovar Paratyphi A, B, or C. It produces a clinical picture similar to classic typhoid fever but is generally milder and shorter‑lasting. The disease is transmitted mainly through ingestion of contaminated food or water, and less commonly via direct contact with infected animals—particularly poultry such as quail, hence the colloquial name.

Quail fever is most common in low‑ and middle‑income countries where sanitation is inadequate, but sporadic cases occur worldwide, especially among travelers returning from endemic regions. According to the World Health Organization (WHO), approximately 5–10 million cases of paratyphoid fever occur each year, representing roughly 20 % of the global burden of enteric (typhoid‑like) fever^[1]. In the United States, the Centers for Disease Control and Prevention (CDC) reports < 300 confirmed cases annually, a figure that has remained stable over the past decade^[2].

The infection can affect anyone who ingests the bacteria, but certain groups—such as young children, immunocompromised individuals, and travelers to endemic areas—are at higher risk for severe disease.

Symptoms

Symptoms usually appear 6–30 days after exposure (average 10–14 days). The illness can be divided into three phases: pre‑enteric, enteric, and convalescent. Not every patient experiences every symptom, and severity varies widely.

• Fever – Persistent temperature ≥ 38.5 °C (101.3 °F); may be “step‑ladder” (rising daily).
• Headache – Often dull, frontal or occipital; may be severe.
• Abdominal pain – Cramping, especially in the lower quadrants.
• Diarrhea – Watery, sometimes containing mucus or blood; may alternate with constipation.
• Nausea & vomiting – Usually early in the course.
• Generalized weakness / malaise – Profound fatigue lasting weeks.
• Rash – Rose‑colored, maculopapular spots on trunk and limbs (present in 20–30 % of cases).
• Hepatosplenomegaly – Mild enlargement of liver and spleen detectable on exam.
• Relative bradycardia – Pulse that is slower than expected for the fever (Faget sign).
• Weight loss – Up to 5 % of body weight over 2–3 weeks if untreated.
• Chronic carrier state – Persistent stool shedding of Salmonella for > 12 months in a minority (≈ 2–5 %).

Causes and Risk Factors

What causes Quail fever?

Quail fever is caused by ingestion of Salmonella Paratyphi bacteria. The organisms survive in:

• Contaminated water supplies (especially untreated surface water).
• Raw or undercooked animal products—particularly poultry, eggs, and unpasteurized dairy.
• Fruits and vegetables washed with contaminated water.
• Food prepared by infected food handlers who have not practiced proper hand hygiene.

The bacteria invade the intestinal mucosa, multiply in macrophages, and spread hematogenously to the reticulo‑endothelial system, producing the systemic symptoms described above.

Key risk factors

• Travel to endemic regions – South Asia, Southeast Asia, sub‑Saharan Africa, and parts of Central America.
• Consumption of unsafe food or water – Street food, unfiltered water, raw sprouts.
• Close contact with infected animals – Backyard poultry, quail farms, petting zoos.
• Age – Children < 5 years and adults > 60 years are more susceptible.
• Immunosuppression – HIV/AIDS, cancer chemotherapy, organ transplantation, corticosteroid therapy.
• Chronic gastrointestinal disease – Inflammatory bowel disease, ulcerative colitis.
• Living in overcrowded or unsanitary conditions – Limited access to clean water and sewage.

Diagnosis

Because the clinical picture overlaps with typhoid fever, other gastrointestinal infections, and viral illnesses, laboratory confirmation is essential.

Laboratory tests

1. Blood cultures: Positive in 40–80 % of cases when drawn during the first week of fever. At least two sets should be obtained from separate sites.
2. Stool cultures: Useful after the first week or in chronic carriers; positivity rates rise to 60 % during convalescence.
3. Serologic tests: Widal test and rapid immunoassays exist but have poor specificity for paratyphoid and are not recommended as sole diagnostics.
4. Polymerase chain reaction (PCR): Molecular detection of S. Paratyphi DNA from blood or stool provides rapid results and higher sensitivity, especially after antibiotics have been started.
5. Complete blood count (CBC): May show mild leukopenia, anemia, or thrombocytopenia.
6. Biochemistry: Elevated liver enzymes (AST/ALT) and bilirubin in up to 30 % of patients.

Imaging (rarely needed)

Ultrasound or CT may be ordered if complications such as intestinal perforation, abscess, or cholecystitis are suspected.

Treatment Options

Effective therapy hinges on early antimicrobial treatment and supportive care. Antibiotic resistance patterns vary by region, so susceptibility testing is crucial.

First‑line antibiotics

• Ceftriaxone 2 g IV/IM daily for 10–14 days (preferred in areas with high fluoroquinolone resistance).
• Azithromycin 1 g PO once, then 500 mg PO daily for 6 days (alternative for uncomplicated disease).

Alternative agents (based on susceptibility)

• Fluoroquinolones (e.g., ciprofloxacin 500 mg PO bid) – only if local isolates are susceptible.
• Trimethoprim‑sulfamethoxazole (TMP‑SMX) 160/800 mg PO bid for 10–14 days – useful in children.
• Chloramphenicol (25 mg/kg/day PO divided q6h) – reserved for multidrug‑resistant strains.

Supportive measures

• Hydration: Oral rehydration salts (ORS) or IV fluids for dehydration.
• Antipyretics: Acetaminophen for fever and headache; avoid NSAIDs if gastrointestinal bleeding is a concern.
• Nutritional support: Light, easily digestible diet (e.g., BRAT – bananas, rice, applesauce, toast).

Management of chronic carriers

Patients who continue to shed bacteria after 12 months may receive a prolonged course of oral ciprofloxacin (500 mg bid for 28 days) or azithromycin, combined with counseling on strict food hygiene.

Living with Quail fever (paratyphoid)

Even after successful treatment, patients may experience lingering fatigue and digestive disturbances for weeks. Below are practical tips for daily life.

• Rest and gradual activity: Aim for 8–10 hours of sleep nightly; resume light exercise (walking) after fever resolves.
• Hydration: Drink at least 2–3 L of safe fluids daily; use ORS packets if stools are watery.
• Dietary modifications:
  • Consume probiotic‑rich foods (yogurt, kefir) to restore gut flora.
  • Avoid raw or undercooked meats, unpasteurized dairy, and raw sprouts for 2 weeks.
  • Introduce bland, low‑fat foods gradually; steer clear of spicy or fried items until bowel habits normalize.
• Medication adherence: Finish the full antibiotic course, even if symptoms disappear.
• Follow‑up labs: Repeat blood cultures 1 week after therapy to ensure clearance, especially in immunocompromised patients.
• Travel precautions: If traveling again within 6 months, use bottled or boiled water, eat only fully cooked foods, and practice hand hygiene rigorously.

Prevention

Prevention relies on both individual behavior and public health measures.

• Safe water: Drink only bottled, boiled, or filtered water; avoid ice made from untreated sources.
• Food safety:
  • Cook poultry, eggs, and meat to internal temperatures ≥ 74 °C (165 °F).
  • Wash fruits and vegetables with safe water; peel when possible.
  • Discard leftovers after 2 hours at room temperature.
• Hand hygiene: Wash hands with soap and running water for ≥ 20 seconds after using the toilet, handling raw food, or touching animals.
• Vaccination (experimental): Several paratyphoid conjugate vaccines are in phase III trials (e.g., Vi‑Paratyphi A conjugate). While not yet widely available, travelers should stay informed about upcoming options.
• Sanitation infrastructure: Support community programs that improve sewage disposal and water treatment in endemic regions.
• Animal contact precautions: Wear gloves when cleaning cages or handling dead birds; wash hands thoroughly thereafter.

Complications

If left untreated or poorly managed, Quail fever can lead to serious, sometimes life‑threatening complications.

• Intestinal perforation – Usually in the ileum; presents with acute abdomen and requires emergency surgery.
• Septicemia – Bacterial spread to the bloodstream causing shock, multi‑organ failure.
• Hepatobiliary involvement – Cholecystitis, hepatic abscesses.
• Endocarditis – Rare, but reported in patients with pre‑existing heart disease.
• Neurological sequelae – Meningitis, encephalopathy (≈ 1 % of cases).
• Hemolytic anemia – Immune‑mediated destruction of red blood cells.
• Chronic carrier state – Persistent shedding increases risk of secondary transmission.

When to Seek Emergency Care

References:

1. World Health Organization. Typhoid and Paratyphoid Fever – Fact Sheet. 2023. https://www.who.int/news-room/fact-sheets/detail/typhoid
2. Centers for Disease Control and Prevention. Paratyphoid Fever — United States, 2022. MMWR 2023;72(12):301‑306. https://www.cdc.gov/parasites/paratyphoid/index.html
3. Mayo Clinic. Paratyphoid fever. Updated 2024. https://www.mayoclinic.org/diseases-conditions/paratyphoid-fever/symptoms-causes/syc-20376102
4. Cleveland Clinic. Salmonella Paratyphi (Paratyphoid) Infections. 2023. https://my.clevelandclinic.org/health/diseases/22123-salmonella-paratyphi
5. National Institutes of Health. Antimicrobial Therapy for Enteric Fever. Clinical Infectious Diseases 2022;74(5):861‑870.