Emergence of<i>Salmonella paratyphi A</i>as a Major Cause of Enteric Fever: Need for Early Detection, Preventive Measures, and Effective Vaccines: Table 1

Fangtham, Monthida; Wilde, Henry

doi:10.1111/j.1708-8305.2008.00237.x

Cited by 52 publications

(65 citation statements)

References 47 publications

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“…While less prevalent than typhoid fever, paratyphoid fever occurs in an estimated 5.4 million cases each year (3)(4)(5)(6). Recent reports indicate that paratyphoid A fever is on the rise in areas of endemicity (e.g., South and Southeast Asia, China) and among travelers returning from those areas (3)(4)(5)(6). The emergence of multiple antibiotic-resistant Salmonella strains has increased the health risks posed by these enteric fever infections (7).…”

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confidence: 99%

“…However, infection with Salmonella enterica serovar Paratyphi A (paratyphoid A fever) or Salmonella enterica serovar Paratyphi B (paratyphoid B fever) causes similar clinical manifestations (2). While less prevalent than typhoid fever, paratyphoid fever occurs in an estimated 5.4 million cases each year (3)(4)(5)(6). Recent reports indicate that paratyphoid A fever is on the rise in areas of endemicity (e.g., South and Southeast Asia, China) and among travelers returning from those areas (3)(4)(5)(6).…”

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confidence: 99%

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Live Oral Salmonella enterica Serovar Typhi Vaccines Ty21a and CVD 909 Induce Opsonophagocytic Functional Antibodies in Humans That Cross-React withS. Paratyphi A andS. Paratyphi B

Wahid

Zafar

McArthur

et al. 2014

Clin. Vaccine Immunol.

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S almonella enterica serovar Typhi (S. Typhi), a human-restricted pathogen, is the causative agent of typhoid fever, the most prevalent form of enteric fever, resulting in an estimated 21.7 million cases and 200,000 deaths per year worldwide (1). However, infection with Salmonella enterica serovar Paratyphi A (paratyphoid A fever) or Salmonella enterica serovar Paratyphi B (paratyphoid B fever) causes similar clinical manifestations (2). While less prevalent than typhoid fever, paratyphoid fever occurs in an estimated 5.4 million cases each year (3-6). Recent reports indicate that paratyphoid A fever is on the rise in areas of endemicity (e.g., South and Southeast Asia, China) and among travelers returning from those areas (3-6). The emergence of multiple antibiotic-resistant Salmonella strains has increased the health risks posed by these enteric fever infections (7).Currently, two licensed vaccines against typhoid fever are available worldwide, parenteral Vi polysaccharide (Vi) and oral live attenuated Ty21a. Nevertheless, each of these vaccines exhibits limitations that have fostered the development of a new generation of vaccines, including both of the engineered live oral typhoid vaccines (e.g., CVD 908-htrA [⌬aroC ⌬aroD ⌬htrA] and CVD 909 [CVD 908-htrA further engineered to constitutively express Vi]) (8) and the M01ZH09 (⌬aroC ⌬ssaV) (9) and Vi carrier protein conjugate vaccines (10). There are, however, no available licensed vaccines against S. Paratyphi A or B.Whole-genome comparative analysis has revealed a high degree of homology among S. Typhi, S. Paratyphi A, and S. Paratyphi B at the DNA level, suggesting the theoretical potential for vaccines against S. Typhi to offer some degree of cross-protection against S. Paratyphi A and S. Paratyphi B (11,12). Vi-based vaccines cannot confer cross-protection, since neither S. Paratyphi A nor S. Paratyphi B expresses Vi antigen. In contrast, large-scale field trials of the efficacy of the oral Ty21a vaccine have documented a moderate level of cross-protection against S. Paratyphi B but not against S. Paratyphi A (13-15). Therefore, the development of an effective vaccine against S. Paratyphi A has emerged as a public health priority (16).We and others have extensively studied the induction of S. Typhi-specific humoral and cellular immune responses (cell-mediated immunity [CMI]) following immunization with Ty21a and other live oral typhoid vaccines in humans (9,(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28) and have also begun to explore the cross-reactive immune responses elicited by the S. Typhi live oral vaccines against S. Paratyphi A and S. Paratyphi B that might explain the observed cross-protection and its serovar limitations (29,30).The capacity of oral typhoid vaccines to induce humoral responses has been well documented, but information on the functional capacity of the induced antibodies has been sparse except for a few reports on specific antibody-enhanced phagocytosis and intracellular killing. In the 1980s, Tagliabue et al. reported that the Ig...

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confidence: 99%

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confidence: 99%

Live Oral Salmonella enterica Serovar Typhi Vaccines Ty21a and CVD 909 Induce Opsonophagocytic Functional Antibodies in Humans That Cross-React withS. Paratyphi A andS. Paratyphi B

Wahid

Zafar

McArthur

et al. 2014

Clin. Vaccine Immunol.

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“…Interestingly, our test also detected patients with S. Paratyphi A bacteremia. Paratyphoid fever caused by S. Paratyphi A accounts for up to 1 in 5 cases of enteric fever is some areas of Asia, including Bangladesh (4), and paratyphoid and typhoid fevers can be clinically indistinguishable (4,23). The S. Typhi LPS serotype is defined by the O antigen, determined by the O-specific oligonucleotide and polysaccharides associated with the LPS.…”

Section: Discussionmentioning

confidence: 99%

Development of a Simple, Peripheral-Blood-Based Lateral-Flow Dipstick Assay for Accurate Detection of Patients with Enteric Fever

Khan¹,

Sayeed

Sultana³

et al. 2016

Clin Vaccine Immunol

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e Enteric fever is a systemic infection caused by typhoidal strains of Salmonella enterica and is a significant cause of mortality and morbidity in many parts of the world, especially in resource-limited areas. Unfortunately, currently available diagnostic tests for enteric fever lack sensitivity and/or specificity. No true clinically practical gold standard for diagnosing patients with enteric fever exists. Unfortunately, microbiologic culturing of blood is only 30 to 70% sensitive although 100% specific. Here, we report the development of a lateral-flow immunochromatographic dipstick assay based on the detection of Salmonella enterica serovar Typhi (S. Typhi) lipopolysaccharide (LPS)-specific IgG in lymphocyte culture secretion. We tested the assay using samples from 142 clinically suspected enteric fever patients, 28 healthy individuals residing in a zone where enteric fever is endemic, and 35 patients with other febrile illnesses. In our analysis, the dipstick detected all blood culture-confirmed S. Typhi cases (48/48) and 5 of 6 Salmonella enterica serovar Paratyphi A blood cultured-confirmed cases. The test was negative in all 35 individuals febrile with other illnesses and all 28 healthy controls from the zone of endemicity. The test was positive in 19 of 88 individuals with suspected enteric fever but with negative blood cultures. Thus, the dipstick had a sensitivity of 98% compared to blood culture results and a specificity that ranged from 78 to 100% (95% confidence interval [CI], 70 to 100%), depending on the definition of a true negative. These results suggest that this dipstick assay can be very useful for the detection of enteric fever patients especially in regions of endemicity.

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“…With increasing incidence and more data now available, studies have started to demonstrate an equivalent or even increased rate of complications with paratyphoid infections (Ekdahl et al, 2005;Vollaard et al, 2005;Woods et al, 2006). S. Paratyphi A, B or C may present with either systemic (Lee et al, 2000;Rajagopal et al, 2002;Mohanty et al, 2003) or localised infection (Fangtham et al, 2008). A relapse rate of 8% has been reported with S. Paratyphi A which is increasing in incidence throughout Southeast Asia (Ochiai et al, 2005;Woods et al, 2006;Fangtham et al, 2008) and may be associated with higher rates of complicated disease and outbreaks of infection (Khan et al, 2007;Pandit et al, 2008;Patel et al, 2010).…”

Section: Fig 1 the Variation Of Oral Temperature During Typhoid Infmentioning

confidence: 99%

“…S. Paratyphi A, B or C may present with either systemic (Lee et al, 2000;Rajagopal et al, 2002;Mohanty et al, 2003) or localised infection (Fangtham et al, 2008). A relapse rate of 8% has been reported with S. Paratyphi A which is increasing in incidence throughout Southeast Asia (Ochiai et al, 2005;Woods et al, 2006;Fangtham et al, 2008) and may be associated with higher rates of complicated disease and outbreaks of infection (Khan et al, 2007;Pandit et al, 2008;Patel et al, 2010). S. Paratyphi A and B may present with a non-specific Salmonella gastroenteritis with diarrhoea being a predominant symptom (Thisyakorn et al, 1987;Yang et al, 2010).…”

Section: Fig 1 the Variation Of Oral Temperature During Typhoid Infmentioning

confidence: 99%

Molecular Diagnosis of Enteric Fever: Progress and Perspectives

Zhou¹,

Darton²,

Waddington³

et al. 2012

Salmonella - Distribution, Adaptation, Control Measures and Molecular Technologies

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Emergence ofSalmonella paratyphi Aas a Major Cause of Enteric Fever: Need for Early Detection, Preventive Measures, and Effective Vaccines: Table 1

Cited by 52 publications

References 47 publications

Live Oral Salmonella enterica Serovar Typhi Vaccines Ty21a and CVD 909 Induce Opsonophagocytic Functional Antibodies in Humans That Cross-React withS. Paratyphi A andS. Paratyphi B

Live Oral Salmonella enterica Serovar Typhi Vaccines Ty21a and CVD 909 Induce Opsonophagocytic Functional Antibodies in Humans That Cross-React withS. Paratyphi A andS. Paratyphi B

Development of a Simple, Peripheral-Blood-Based Lateral-Flow Dipstick Assay for Accurate Detection of Patients with Enteric Fever

Molecular Diagnosis of Enteric Fever: Progress and Perspectives

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