Overview
Enteric fever is a systemic infection caused by Salmonella enterica serovars Typhi and Paratyphi, collectively referred to as typhoid and paratyphoid fever. It is characterized by sustained high fever, abdominal pain and a range of systemic symptoms.
Explanation
Salmonella Typhi and Paratyphi are human-adapted Gram-negative bacilli transmitted via ingestion of food or water contaminated with feces from infected individuals or carriers. After surviving gastric acid, the bacteria invade intestinal epithelial cells, are taken up by macrophages and spread to the reticuloendothelial system via the bloodstream. Their ability to survive within phagocytic cells leads to a prolonged bacteremia and systemic manifestations. The incubation period ranges from 6 to 30 days. Patients present with stepwise fever, malaise, headache, abdominal discomfort, constipation or diarrhea, and sometimes faint, rose-colored skin spots. Without treatment, serious complications such as intestinal hemorrhage, perforation, encephalopathy and septic shock can occur. Diagnosis relies on isolation of the organism from blood, bone marrow or stool cultures; serologic tests like the Widal test lack specificity. Effective therapy includes fluoroquinolones, third-generation cephalosporins or azithromycin, but multidrug-resistant strains require careful selection. Chronic carriage, often in the gallbladder, can persist after infection and contribute to transmission. Preventive measures include vaccination with Vi polysaccharide or conjugate vaccines and live attenuated oral formulations, along with improved sanitation and food hygiene.
Clinical presentation and control
Enteric fever remains endemic in many regions of South Asia, sub-Saharan Africa and parts of Latin America where access to clean water is limited. Travelers from industrialized countries may acquire infection when visiting endemic areas. Typhoid fever accounts for most cases, but paratyphoid fever due to serovars Paratyphi A, B and C often produces similar but milder illness. Historically, asymptomatic carriers like “Typhoid Mary” were sources of outbreaks. Public health efforts focus on identification and treatment of cases, vaccination campaigns in high-incidence areas, and infrastructure improvements to reduce fecal contamination. Surveillance and antimicrobial stewardship are critical to detect emerging resistance and guide therapy.
Enteric fever encompasses typhoid and paratyphoid fever caused by human-restricted Salmonella enterica serovars. Awareness of its transmission routes, clinical features and control strategies is vital for clinicians and public health authorities.
Related Terms: Salmonella Typhi, Paratyphi, Typhoid fever, Carrier, Vaccination