Typhoid and paratyphoid fever: a clinical seminar

Abstract

Rationale for review Enteric fever (EF) caused by Salmonella enterica subspecies enterica serovar Typhi (Salmonella Typhi) & S. Paratyphi (Salmonella Paratyphi) remains an important cause of infectious morbidity and mortality in many low-income countries, and therefore still poses a major infectious risk for travelers to endemic countries. Main findings Although the global burden of EF has decreased over the past two decades, prevalence of EF remains high in Asia and Africa, with the highest prevalence reported from the Indian subcontinent. These statistics are mirrored by data on travel-related EF. Widespread and increasing antimicrobial resistance has narrowed treatment options for travel-related EF. Ceftriaxone and azithromycin-based therapies are commonly used, even with the emergence of extremely drug resistant (XDR) typhoid in Pakistan. Preventive measures among locals and travelers include provision of safe food and water and vaccination. Food and water precautions offer limited protection and the efficacy of Salmonella Typhi vaccines are only moderate signifying the need for travelers to be extra cautious. Recommendations Improvement in the diagnosis of typhoid with high degree of clinical suspicion, better diagnostic assays, early and accurate detection of resistance, therapy with appropriate drugs, improvements in hygiene and sanitation with provision of safe drinking water in endemic areas and vaccination among travellers as well as in the endemic population are keys to controlling typhoid. While typhoid vaccines are recommended for travellers to high risk areas, moderate efficacy and inability to protect against Salmonella Paratyphi are limitations to bear in mind. Improved Salmonella Typhi vaccines and vaccines against Salmonella Paratyphi A are required.

Typhoid fever in travellers: estimating the risk of acquisition by country

“…However, despite limited data suggesting the oral typhoid vaccine may provide cross-protection for Salmonella Paratyphi B (albeit without established effectiveness for either Salmonella Paratyphi A or C), 2 Salmonella Paratyphi currently has no licensed vaccines available. 3 …”

“…The sensitivity of culture is dependent both on the volume of blood collected and prior antibiotic use. 3–5 Bone marrow sampling for culture may increase diagnostic sensitivity, but this is offset by added resource use, procedural risks and patient discomfort which preclude its routine use in the work-up of suspected cases. In most regions of high typhoid endemicity, underdiagnosis related to low rates of presentation to health care, as well as lack of diagnostic testing facilities, making it difficult to accurately measure the burden of typhoid disease on a global scale.…”

Paratyphoid Fever A: Infection and Prevention

“…From the initial infection site in the Peyer's patches, the bacteria access the mesenteric lymph nodes, and finally enter the blood through the output lymphatic vessels. After disseminating to systemic tissues, Salmonella cells replicate in the phagocytes of spleen, liver and bone marrow, resulting in serious lesions (Manesh et al, 2021).…”

Historic and Prehistoric Epidemics: An Overview of Sources Available for the Study of Ancient Pathogens

“…Indeed, epistaxis, and a so-called 'rose spot' rash are clinical symptoms of enteric fever, although they are not the most prominent ones. Age, geography, and the specific causative organism are known to widely influence the signs and complications of enteric fever [160,161].…”