A study of typhoid fever in five Asian countries: disease burden and implications for controls

Safety and immunogenicity of conjugate vaccine for typhoid (Vi-DT): Finding from an observer-blind, active-controlled, randomized, non-inferiority, phase III clinical trial among healthy volunteers

Typhoid fever is a significant public health concern with most of the sufferers between 15 and 25 y of age in Nepal. We undertook this study to demonstrate Vi polysaccharide conjugated with diphtheria toxoid (Vi-DT) conjugate vaccine which is non-inferior to Typbar typhoid conjugate vaccine, a Vi polysaccharide vaccine conjugated with tetanus toxoid (Vi-TT) with a focus on the adult population from Dhulikhel Hospital which was one of the total four sites in Nepal. In this study, we assigned the eligible participants in 1:1:1:1 ratio by block randomization, and stratified into three age groups (6 months to less than 2 y, 2 y to less than 18 y, and 18 y to 45 y), allotted to Group A, B, C, and D. Group A, B, and C received 25 μg (0.5 mL) of Vi-DT study vaccine and participants in Group D received 25 μg (0.5 mL) Vi-TT vaccine. We descriptively analyzed safety in all the participants receiving one dose of the investigational vaccine. The anti-Vi-IgG seroconversion rate in Vi-DT recipients was 99.71% (97.5% CI 98.04-99.96; 344 of 345 participants) and 99.13% (94.27-99.87; 114 of 115) in Vi-TT recipients which indicates that Vi-DT vaccine is non-inferior to Vi-TT vaccine. In safety aspect, 16.81% of total subject had at least one solicited adverse reaction and 22.61% of the Vi-TT participants experienced at least one solicited adverse reaction with most of them being local adverse reactions. None of the enrolled participants reported serious adverse events. Our study shows that a single dose of the Vi-DT vaccine is immunogenic, safe to administer and non-inferior to the Vi-TT vaccine four weeks after vaccination.

Clinical characteristics of enteric fever and performance of TUBEX TF IgM test in Indonesian hospitals

BACKGROUND

Accurate diagnosis of enteric fever is challenging, particularly in low- and middle-income countries, due to the overlap of clinical and laboratory features with other pathogens. To better understand the difficulties in enteric fever diagnosis, we evaluated the characteristics of patients clinically diagnosed with enteric fever and the real-world performance of TUBEX TF, one of the most used tests in Indonesia.

METHODOLOGY/PRINCIPAL FINDINGS

Patients were recruited through the AFIRE (Etiology of Acute Febrile Illness Requiring Hospitalization) study at eight Indonesian hospitals. Blood culture was performed for all patients, and TUBEX TF was performed for suspected enteric cases. Salmonella PCR and ELISA tests were performed at a reference lab. Sensitivity and specificity of TUBEX TF and IgM and IgG anti-S. Typhi ELISA were determined. Of 301 patients clinically diagnosed with enteric fever, 50 (16.6%) were confirmed by blood culture and/or PCR. Confirmed cases were mostly school-aged children presenting with fever, anorexia, dizziness and/or abdominal pain with normal leukocyte count or leukopenia. TUBEX TF demonstrated a sensitivity of 97.6% to 70.7% and specificity of 38.3% to 67.2% at cutoffs of 4 and 6, respectively. Acute IgG demonstrated the best sensitivity and specificity, at 90.7% and 82.7%, respectively, and the best ROC characteristics.

CONCLUSIONS/SIGNIFICANCE

A substantial proportion of enteric fever was misdiagnosed at all study hospitals, likely due to the overlap of clinical characteristics and lab parameters with those of other common pathogens. The TUBEX TF rapid serological assay demonstrated suboptimal performance in our setting and tended to over-diagnose enteric fever. The role of IgG from acute specimens for identification of enteric fever cases merits additional consideration.

The origins of haplotype 58 (H58) Salmonella enterica serovar Typhi

Antimicrobial resistance (AMR) poses a serious threat to the clinical management of typhoid fever. AMR in Salmonella Typhi (S. Typhi) is commonly associated with the H58 lineage, a lineage that arose comparatively recently before becoming globally disseminated. To better understand when and how H58 emerged and became dominant, we performed detailed phylogenetic analyses on contemporary genome sequences from S. Typhi isolated in the period spanning the emergence. Our dataset, which contains the earliest described H58 S. Typhi organism, indicates that ancestral H58 organisms were already multi-drug resistant (MDR). These organisms emerged spontaneously in India in 1987 and became radially distributed throughout South Asia and then globally in the ensuing years. These early organisms were associated with a single long branch, possessing mutations associated with increased bile tolerance, suggesting that the first H58 organism was generated during chronic carriage. The subsequent use of fluoroquinolones led to several independent mutations in gyrA. The ability of H58 to acquire and maintain AMR genes continues to pose a threat, as extensively drug-resistant (XDR; MDR plus resistance to ciprofloxacin and third generation cephalosporins) variants, have emerged recently in this lineage. Understanding where and how H58 S. Typhi originated and became successful is key to understand how AMR drives successful lineages of bacterial pathogens. Additionally, these data can inform optimal targeting of typhoid conjugate vaccines (TCVs) for reducing the potential for emergence and the impact of new drug-resistant variants. Emphasis should also be placed upon the prospective identification and treatment of chronic carriers to prevent the emergence of new drug resistant variants with the ability to spread efficiently.

Tackling salmonellosis: A comprehensive exploration of risks factors, impacts, and solutions

Salmonellosis, caused by Salmonella species, is one of the most common foodborne illnesses worldwide with an estimated 93.8 million cases and about 155,00 fatalities. In both industrialized and developing nations, Salmonellosis has been reported to be one of the most prevalent foodborne zoonoses and is linked with arrays of illness syndromes such as acute and chronic enteritis, and septicaemia. The two major and most common Salmonella species implicated in both warm-blooded and cold-blooded animals are Salmonella bongori and Salmonella enterica. To date, more than 2400 S. enterica serovars which affect both humans and animals have been identified. Salmonella is further classified into serotypes based on three primary antigenic determinants: somatic (O), flagella (H), and capsular (K). The capacity of nearly all Salmonella species to infect, multiply, and survive in human host cells with the aid of their pathogenic and virulence arsenals makes them deadly and important public health pathogens. Primarily, food-producing animals such as poultry, swine, cattle, and their products have been identified as important sources of salmonellosis. Additionally, raw fruits and vegetables are among other food types that have been linked to the spread of Salmonella spp. Based on the clinical manifestation of human salmonellosis, Salmonella strains can be categorized as either non-typhoidal Salmonella (NTS) and typhoidal Salmonella. The detection of aseptically collected Salmonella in necropsies, environmental samples, feedstuffs, rectal swabs, and food products serves as the basis for diagnosis. In developing nations, typhoid fever due to Salmonella Typhi typically results in the death of 5%-30% of those affected. The World Health Organization (WHO) calculated that there are between 16 and 17 million typhoid cases worldwide each year, with scaring 600,000 deaths as a result. The contagiousness of a Salmonella outbreak depends on the bacterial strain, serovar, growth environment, and host susceptibility. Risk factors for Salmonella infection include a variety of foods; for example, contaminated chicken, beef, and pork. Globally, there is a growing incidence and emergence of life-threatening clinical cases, especially due to multidrug-resistant (MDR) Salmonella spp, including strains exhibiting resistance to important antimicrobials such as beta-lactams, fluoroquinolones, and third-generation cephalosporins. In extreme cases, especially in situations involving very difficult-to-treat strains, death usually results. The severity of the infections resulting from Salmonella pathogens is dependent on the serovar type, host susceptibility, the type of bacterial strains, and growth environment. This review therefore aims to detail the nomenclature, etiology, history, pathogenesis, reservoir, clinical manifestations, diagnosis, epidemiology, transmission, risk factors, antimicrobial resistance, public health importance, economic impact, treatment, and control of salmonellosis.

Safety and immunogenicity of Vi-diphtheria toxoid typhoid conjugate vaccine among children below 2 years: a systematic review and meta-analysis

Background

The Vi-diphtheria toxoid typhoid conjugate vaccine (Vi-DT) has shown promising results in preventing typhoid fever in children under 2 years of age. However, a thorough assessment of its safety and immunogenicity is required to inform vaccination strategies. This systematic review and meta-analysis aimed to determine the safety and immunogenicity of Vi-DT in children below 2 years.

Methods

We systematically searched multiple databases, including PubMed, Web of Science, and Scopus, for relevant studies published up to September 2023. We included studies reporting on the safety and immunogenicity outcomes of Vi-DT compared to the control or Vi-tetanus toxoid conjugated vaccine (Vi-TT) in children below 2 years. We applied a random-effects model for meta-analysis using RevMan 5.4. We expressed the results as risk ratio (RR) with a 95% confidence interval (95%CI).

Results

In this analysis, five studies were selected, encompassing 1,292 children under 2 years who received the Vi-DT vaccine. No significant difference in immediate reactions was observed within 30 min post-vaccination between Vi-DT and control groups (RR: 0.99 [95% CI: 0.19, 5.26]), nor between Vi-DT and Vi-TT groups. For solicited adverse events within 4 weeks, the VI-DT group showed no significant increase in adverse events compared to control (RR: 0.93 [95% CI: 0.78, 1.12]) or Vi-TT (RR: 0.86 [95% CI: 0.69, 1.07]). Similarly, within 7 days post-vaccination, risk ratios indicated no significant differences in adverse events between the groups. The 4-week seroconversion rate was significantly higher in the Vi-DT group compared to the control (RR: 1.99 [95% CI: 1.07, 3.69]), but no difference was found between Vi-DT and Vi-TT. Adverse events associated with typhoid conjugate vaccines were predominantly non-serious, including fever and injection site reactions. Serious adverse events were rare but included conditions like pneumonia and gastroenteritis.

Conclusion

This meta-analysis highlights Vi-DT safety and immunogenicity in six to 24-month-old children. The findings support the use of this Vi-DT to expand typhoid vaccination in endemic regions, in line with WHO's strategy.

Shifting targets: typhoid's transformation from an environmental to a vaccine-preventable disease, 1940-2019

160 years after the discovery of its waterborne transmission and 120 years after the development of the first-generation of vaccines, typhoid fever remains a major health threat globally. In this Historical Review, we use WHO's Institutional Repository for Information Sharing to examine changes in typhoid control policy from January, 1940, to December, 2019. We used a mixed-methods approach in the analysis of infection control priorities, combining semi-inductive thematic coding with historical analysis to show major thematic shifts in typhoid control policy, away from water, sanitation, and hygiene (WASH)-based control towards vaccine-based interventions concurrent with declining attention to the disease. Documentary analysis shows that, although international planners never officially disavowed WASH and low-income countries persistently lobbied for WASH, vaccines emerged as a permanent stopgap while meaningful support of sustained WASH strengthening lost momentum-with serious, long-term ramifications for typhoid control.

Clinical and antimicrobial susceptibility profile of typhoid fever in children in the era of antibiotic resistance

Enteric fever remains a significant public health problem in low- and middle-income countries with further challenges from emerging antimicrobial resistance. Our prospective study evaluated the current clinical and antimicrobial susceptibility profile of enteric fever in 88 children and compared it to previously established literature. Enteric fever usually presents with nonspecific signs and symptoms, with predominant respiratory complaints. A paradigm shift in the antimicrobial sensitivity pattern has been noted, with increasing resistance for first-line antibiotics and older antibiotics such as ampicillin, cotrimoxazole, and chloramphenicol showing good sensitivity. Thus, the introduction of the latter merits consideration.

Tracking the shift in enteric fever trends and evolving antibiotic sensitivity patterns

Objective

This study aims to examine the frequency of Salmonella Paratyphi found in blood cultures and evaluate the antibiotic susceptibility pattern of Salmonella isolates to different antibiotics. Additionally, the study aims to assess the paradigm shift in the trend of enteric fever caused by Salmonella Typhi (S. Typhi) to Salmonella Paratyphi(S. Paratyphi) .

Study Design

Retrospective study.

Participant

The study enrolled patients aged 12 years and above diagnosed with enteric fever (positive blood culture) and admitted to Peelamedu Samanaidu Govindasamy Naidu (PSG) Hospital.

Interventions

The study analyzed demographic and antibiotic susceptibility profiles of Salmonella isolates collected from 106 enteric fever patients in the hospital between 2010 and 2022. The susceptibility profiles of Salmonella isolates to multiple antibiotics were assessed.

Results

There were 106 participants, and 95 (89.62%) of them had enteric fever linked to Salmonella Typhi, while only 11 (10.38%) had enteric fever linked to Salmonella Paratyphi A. From 2010 to 2022, the study discovered a general decline in the prevalence of enteric fever caused by Salmonella species. But between 2014 and 2022, the incidence of enteric fever linked to S. Typhi rapidly increased. Azithromycin (100% , n = 106) and ceftriaxone (99% , n = 105) were highly effective against the Salmonella isolates, whereas nalidixic acid was resisted by 3 isolates (4.72%, n = 3).

Conclusion

The study observed a higher incidence of Salmonella Typhi in comparison to Paratyphi A and a greater susceptibility of males to enteric fever.

Funding

None declared.

Salmonella Subcutaneous Abscess: A Rare Complication Post Salmonella Gastroenteritis

Salmonella is a gram-negative bacilli bacterium that can infect and colonize humans, causing a wide range of clinical manifestations. The most common manifestation is gastroenteritis, usually after ingestion of undercooked and ill-prepared food, particularly in developing countries. Indonesia is among those reported to have a high incidence of Salmonella infection. Uncommonly, extraintestinal manifestations can affect distant body sites, either during or after the episode of bacteremia. This case report presents a rare case of a healthy 19-year-old female who developed an atypical chest wall abscess colonized by Salmonella in the context of experiencing gastroenteritis three weeks prior on her return from Bali, Indonesia. This case highlights the indolent course associated with a Salmonella chest wall abscess with a discussion of the current literature and management.

Salmonella infection among the pediatric population at a tertiary care children's hospital in central Nepal: a retrospective study

Background

Typhoid fever, an infective bacterial disease, is capable of causing fatal systemic infection in humans, and in an era of antimicrobial resistance, it has become of public health importance. This study aimed to investigate the laboratory diagnosis of Salmonella bloodstream infection, its serotype, antimicrobial resistance pattern, and seasonal variation at a tertiary care children's hospital.

Methods

We undertook a retrospective, cross-sectional study by reviewing hospital-based laboratory records of patients whose blood culture samples were submitted from the outpatient department to the laboratory of a tertiary care children's hospital in Kathmandu, Nepal, from January 2017 to January 2019.

Results

Among the total blood culture samples obtained (n = 39,771), bacterial isolates (n = 1,055, 2.65%) belonged either to the Genus Enterobacteriaceae or Genus Acinetobacter. Altogether (n = 91, 8.63%), isolates were positive for Salmonella spp., which were further identified as Salmonella enterica subsp. enterica ser. Typhi (n = 79, 7.49%), Salmonella enterica subsp. enterica ser. Paratyphi A (n = 11, 1.04%), and Salmonella enterica subsp. enterica ser. Paratyphi B (n = 1, 0.1%). The median age of patients was 6  years (IQR: 4-9), with male and female patients constituting (n = 53, 58.24%; OR, 1.0; 95% CI, 0.60-1.67) and (n = 38, 41.76%; OR, 0.98; 95% CI, 0.49-2.05) cases, respectively. The disease was observed throughout the year, with a high prevalence toward the spring season (March-May). An antibiogram showed resistance more toward nalidixic acid with S. Typhi, comprising half the isolates (n = 52, 65.82%; p = 0.11). Resistance toward β-lactams with β-lactamase inhibitors (amoxicillin/clavulanate; 1.27%) was seen in a single isolate of S. Typhi. The multidrug resistance pattern was not pronounced. The multiple antibiotic resistance (MAR) index was in the range between 0.14 and 0.22 in S. Typhi and 0.22 and 0.23 in S. Paratyphi.

Conclusion

Salmonella Typhi was the predominant ser. Infection was common among children between 1 and 5 years of age, showing male predominance and with the spring season contributing to a fairly higher number of cases. Antimicrobial susceptibility testing of S. Typhi showed more resistance toward nalidixic acid, with only a single isolate resistant to β-lactamase inhibitors (amoxicillin/clavulanate). Alarming multidrug resistance patterns were not observed. The MAR index in this study indicates the importance of the judicious use of antimicrobials and hospital infection prevention and control practices.

South Asian Transplant Infectious Disease Guidelines for Solid Organ Transplant Candidates, Recipients, and Donors

These guidelines discuss the epidemiology, screening, diagnosis, posttransplant prophylaxis, monitoring, and management of endemic infections in solid organ transplant (SOT) candidates, recipients, and donors in South Asia. The guidelines also provide recommendations for SOT recipients traveling to this region. These guidelines are based on literature review and expert opinion by transplant physicians, surgeons, and infectious diseases specialists, mostly from South Asian countries (India, Pakistan, Bangladesh, Nepal, and Sri Lanka) as well as transplant experts from other countries. These guidelines cover relevant endemic bacterial infections (tuberculosis, leptospirosis, melioidosis, typhoid, scrub typhus), viral infections (hepatitis A, B, C, D, and E; rabies; and the arboviruses including dengue, chikungunya, Zika, Japanese encephalitis), endemic fungal infections (mucormycosis, histoplasmosis, talaromycosis, sporotrichosis), and endemic parasitic infections (malaria, leishmaniasis, toxoplasmosis, cryptosporidiosis, strongyloidiasis, and filariasis) as well as travelers' diarrhea and vaccination for SOT candidates and recipients including travelers visiting this region. These guidelines are intended to be an overview of each topic; more detailed reviews are being published as a special supplement in the Indian Journal of Transplantation .

Population structure and antimicrobial resistance patterns of Salmonella Typhi and Paratyphi A amid a phased municipal vaccination campaign in Navi Mumbai, India

We performed whole-genome sequencing of 174 Salmonella Typhi and 54 Salmonella Paratyphi A isolates collected through prospective surveillance in the context of a phased typhoid conjugate vaccine introduction in Navi Mumbai, India. We investigate the temporal and geographical patterns of emergence and spread of antimicrobial resistance. We evaluated the relationship between the spatial distance between households and genetic clustering of isolates. Most isolates were non-susceptible to fluoroquinolones, with nearly 20% containing ≥3 quinolone resistance-determining region mutations. Two H58 isolates carried an IncX3 plasmid containing blaSHV-12, associated with ceftriaxone resistance, suggesting that the ceftriaxone-resistant isolates from India independently evolved on multiple occasions. Among S. Typhi, we identified two main clades circulating (2.2 and 4.3.1 [H58]); 2.2 isolates were closely related following a single introduction around 2007, whereas H58 isolates had been introduced multiple times to the city. Increasing geographic distance between isolates was strongly associated with genetic clustering (odds ratio [OR] = 0.72 per km; 95% credible interval [CrI]: 0.66-0.79). This effect was seen for distances up to 5 km (OR = 0.65 per km; 95% CrI: 0.59-0.73) but not seen for distances beyond 5 km (OR = 1.02 per km; 95% CrI: 0.83-1.26). There was a non-significant reduction in odds of clustering for pairs of isolates in vaccination communities compared with non-vaccination communities or mixed pairs compared with non-vaccination communities. Our findings indicate that S. Typhi was repeatedly introduced into Navi Mumbai and then spread locally, with strong evidence of spatial genetic clustering. In addition to vaccination, local interventions to improve water and sanitation will be critical to interrupt transmission. IMPORTANCE Enteric fever remains a major public health concern in many low- and middle-income countries, as antimicrobial resistance (AMR) continues to emerge. Geographical patterns of typhoidal Salmonella spread, critical to monitoring AMR and planning interventions, are poorly understood. We performed whole-genome sequencing of S. Typhi and S. Paratyphi A isolates collected in Navi Mumbai, India before and after a typhoid conjugate vaccine introduction. From timed phylogenies, we found two dominant circulating lineages of S. Typhi in Navi Mumbai-lineage 2.2, which expanded following a single introduction a decade prior, and 4.3.1 (H58), which had been introduced repeatedly from other parts of India, frequently containing "triple mutations" conferring high-level ciprofloxacin resistance. Using Bayesian hierarchical statistical models, we found that spatial distance between cases was strongly associated with genetic clustering at a fine scale (<5 km). Together, these findings suggest that antimicrobial-resistant S. Typhi frequently flows between cities and then spreads highly locally, which may inform surveillance and prevention strategies.

Enteric Fever: Diagnostic Challenges and the Importance of Early Intervention

Enteric fever is a systemic infection caused by highly virulent Salmonella enterica serovars: Typhi and Paratyphi. Diagnosis of enteric fever is challenging due to a wide variety of clinical features which overlap with other febrile illnesses. The current diagnostic methods are limited because of the suboptimal sensitivity of conventional tests like blood culture in detecting organisms and the invasive nature of bone marrow culture. It emphasizes the need to develop improved and more reliable diagnostic modalities. The rising rates of multidrug-resistant Salmonella strains call for an accurate understanding of the current management of the disease. Proper public health measures and large-scale immunization programs will help reduce the burden of the disease. A comprehensive surveillance system can help detect the chronic carrier state and is crucial in understanding antibiotic susceptibility patterns. We conducted an all-language literature search on Medline, Cochrane, Embase, and Google Scholar till May 2022. The following search words and medical subject headings (MeSH) were used: "enteric fever," "Salmonella Typhi," "multidrug-resistant Salmonella," chronic carrier state," "Salmonella detection, "and "typhoid vaccine." We reviewed the literature on clinical features, pathophysiology, new diagnostic tests, and interventions to prevent the disease. This article explores enteric fever and its various clinical features and addresses the emerging threat of multidrug resistance. It focuses on novel methods for diagnosis and prevention strategies, including vaccines and the use of surveillance systems employed across different parts of the world.

Burden of Typhoid and Paratyphoid Fever in India

BACKGROUND

In 2017, more than half the cases of typhoid fever worldwide were projected to have occurred in India. In the absence of contemporary population-based data, it is unclear whether declining trends of hospitalization for typhoid in India reflect increased antibiotic treatment or a true reduction in infection.

METHODS

From 2017 through 2020, we conducted weekly surveillance for acute febrile illness and measured the incidence of typhoid fever (as confirmed on blood culture) in a prospective cohort of children between the ages of 6 months and 14 years at three urban sites and one rural site in India. At an additional urban site and five rural sites, we combined blood-culture testing of hospitalized patients who had a fever with survey data regarding health care use to estimate incidence in the community.

RESULTS

A total of 24,062 children who were enrolled in four cohorts contributed 46,959 child-years of observation. Among these children, 299 culture-confirmed typhoid cases were recorded, with an incidence per 100,000 child-years of 576 to 1173 cases in urban sites and 35 in rural Pune. The estimated incidence of typhoid fever from hospital surveillance ranged from 12 to 1622 cases per 100,000 child-years among children between the ages of 6 months and 14 years and from 108 to 970 cases per 100,000 person-years among those who were 15 years of age or older. Salmonella enterica serovar Paratyphi was isolated from 33 children, for an overall incidence of 68 cases per 100,000 child-years after adjustment for age.

CONCLUSIONS

The incidence of typhoid fever in urban India remains high, with generally lower estimates of incidence in most rural areas. (Funded by the Bill and Melinda Gates Foundation; NSSEFI Clinical Trials Registry of India number, CTRI/2017/09/009719; ISRCTN registry number, ISRCTN72938224.).

Vi polysaccharide and conjugated vaccines afford similar early, IgM or IgG-independent control of infection but boosting with conjugated Vi vaccines sustains the efficacy of immune responses

Introduction

Vaccination with Vi capsular polysaccharide (Vi-PS) or protein-Vi typhoid conjugate vaccine (TCV) can protect adults against Salmonella Typhi infections. TCVs offer better protection than Vi-PS in infants and may offer better protection in adults. Potential reasons for why TCV may be superior in adults are not fully understood.

Methods and results

Here, we immunized wild-type (WT) mice and mice deficient in IgG or IgM with Vi-PS or TCVs (Vi conjugated to tetanus toxoid or CRM197) for up to seven months, with and without subsequent challenge with Vi-expressing Salmonella Typhimurium. Unexpectedly, IgM or IgG alone were similarly able to reduce bacterial burdens in tissues, and this was observed in response to conjugated or unconjugated Vi vaccines and was independent of antibody being of high affinity. Only in the longer-term after immunization (>5 months) were differences observed in tissue bacterial burdens of mice immunized with Vi-PS or TCV. These differences related to the maintenance of antibody responses at higher levels in mice boosted with TCV, with the rate of fall in IgG titres induced to Vi-PS being greater than for TCV.

Discussion

Therefore, Vi-specific IgM or IgG are independently capable of protecting from infection and any superior protection from vaccination with TCV in adults may relate to responses being able to persist better rather than from differences in the antibody isotypes induced. These findings suggest that enhancing our understanding of how responses to vaccines are maintained may inform on how to maximize protection afforded by conjugate vaccines against encapsulated pathogens such as S. Typhi.

A multicenter, single-blind, randomized, phase-2/3 study to evaluate immunogenicity and safety of a single intramuscular dose of biological E's Vi-capsular polysaccharide-CRM197 conjugate typhoid vaccine (TyphiBEVTM) in healthy infants, children, and adults in comparison with a licensed comparator

The current scenario of typhoid fever warrants early prevention with typhoid conjugate vaccines in susceptible populations to provide lifelong protection. We conducted a multicenter, single-blind, randomized, Phase 2/3 study to assess the immunogenicity and safety of Biological E’s Typhoid Vi-CRM₁₉₇ conjugate vaccine (TyphiBEV^TM) compared to Vi-TT conjugate vaccine manufactured by Bharat Biotech International Limited (Typbar-TCV; licensed comparator) in healthy infants, children, and adults from India. The study’s primary objective was to assess the non-inferiority of TyphiBEV^TM in terms of the difference in the proportion of subjects seroconverted with a seroconversion threshold value of ≥2.0 µg/mL against Typbar-TCV. A total of 622 healthy subjects (311 each in both vaccine groups) were randomized and received the single dose of the study vaccine. The TyphiBEV^TM group demonstrated noninferiority compared to the Typbar-TCV group at Day 42. The lower 2-sided 95% confidence interval limit of the group difference was −.34%, which met the non-inferiority criteria of ≥10.0%. The geometric mean concentration (24.79 µg/mL vs. 26.58 µg/mL) and proportion of subjects who achieved ≥4-fold increase in antiVi IgG antibody concentrations (96.95% vs. 97.64%) at Day 42 were comparable between the TyphiBEV^TM and Typbar-TCV vaccine groups. No apparent difference was observed in the safety profile between both vaccine groups. All adverse events reported were mild or moderate in intensity in all age subsets. This data demonstrates that TyphiBEV^TM is non-inferior to TypbarTCV in terms of immunogenicity, and the overall safety and reactogenicity in healthy infants, children, and adults studied from India was comparable.

Clinical Features, Antimicrobial Resistance, and Serogroups of Nontyphoidal Salmonella Isolated From Infants Less Than 3 Months Old in the Recent Decade

BACKGROUND

Antibiotic treatment is indicated for infants with nontyphoidal Salmonella (NTS) enterocolitis. However, whether antimicrobial resistance (AMR) is a problem among young infants is unknown. This study investigated the characteristics of NTS infections in young infants.

METHODS

Infants less than 3 months old with NTS infections were enrolled and grouped into 2 cohorts (diagnosed 2010-2015 or 2016-2021). Salmonella isolated from blood or cerebrospinal fluid was defined as invasive NTS (iNTS). The clinical features, AMR and serogroups were compared between cohorts.

RESULTS

In total, 102 young infants had NTS infections, 6.9% of which were iNTS. Infants with iNTS infections were younger, hospitalized longer, and received longer antibiotic courses. More than half of cases of iNTS were resistant to ciprofloxacin, ceftriaxone and greater than or equal to 3 antibiotics. iNTS was mainly observed in Salmonella groups C2 and E. Over the past decade, group B (44%), group E (26%) and group C2 (16%) have been the most common serogroups. NTS significantly increased AMR to ciprofloxacin, ceftriaxone and trimethoprim-sulfamethoxazole, and greater than or equal to 3 antibiotics. Both multidrug resistance and extensive drug resistance in NTS also significantly increased.

CONCLUSIONS

The serogroups varied with time, and the main causes of iNTS, groups C2 and E, increased over the past decade. The prevalence of AMR also increased, especially for iNTS. Given the low iNTS rate and high AMR, routine antibiotic use among infants with NTS infections between 1 and 3 months old should be reconsidered. Further large-scale research is required to formulate therapeutic strategies.

Microbial and Parasitic Contamination of Vegetables in Developing Countries and Their Food Safety Guidelines

The safety of humans is of paramount importance in the vegetable production chain. Evidence of microbial and parasitic contamination of these products poses a great threat to consumers. This is an emerging issue the world is battling, and it is still in the process of unravelling. However, one of the contributing factors responsible for the rapid spread of these pathogens to millions of people among other factors is the distribution of food in our food systems. The purpose of this study was to draw the attention of producers, retailers, consumers, and various stakeholders to the occurrence and potential hazard of these organisms, their contamination origin, and food safety protocols. Among the food system, vegetables play a major role, and their consumption has increased as they form a larger portion of daily diets. This urge for healthy diets coupled with changing dietary habits and human population explosion has therefore accelerated their production. This has resulted in parasitic and microbial contamination gaining grounds in salad vegetables, and as such, a wide range of microbes such as Escherichia coli O157: H7, Listeria monocytogenes, Salmonella spp., Shigella, and Staphylococcus, and parasites such as Giardia lamblia, Entamoeba coli, Entamoeba histolytica, Cystoisospora belli, Toxoplasma gondii, Trichuris trichiura, and Ascaris lumbricoides have been isolated from them. Therefore, major routes for salad vegetable contamination and prevention methods have been pointed out in this review article. The topic of protective countermeasures will also be covered here in this review. Notwithstanding, several control measures have been reported to be effective and efficient in removing or eliminating pathogens, including treatment of irrigation water and fertilizers, use of disinfectants like vinegar and saltwater, irradiation, ozone, and bacteriophages. Though consumption of vegetables and salads is encouraged due to their nutritional advantage, appropriate systems should be put in place to ensure their safety.

Spatiotemporal and Seasonal Trends of Class A and B Notifiable Infectious Diseases in China: A Retrospective Analysis (Preprint)

BACKGROUND

China is the most populous country globally and has made significant achievements in the control of infectious diseases over the last decades. The 2003 SARS epidemic triggered the initiation of the China Information System for Disease Control and Prevention (CISDCP). Since then, numerous studies have investigated the epidemiological features and trends of individual infectious diseases in China; however, few considered the changing spatiotemporal trends and seasonality of these infectious diseases over time.

OBJECTIVE

This study aims to systematically review the spatiotemporal trends and seasonal characteristics of class A and class B notifiable infectious diseases in China during 2005-2020.

METHODS

We extracted the incidence and mortality data of 8 types (27 diseases) of notifiable infectious diseases from the CISDCP. We used the Mann-Kendall and Sen's methods to investigate the diseases' temporal trends, Moran I statistic for their geographical distribution, and circular distribution analysis for their seasonality.

RESULTS

Between January 2005 and December 2020, 51,028,733 incident cases and 261,851 attributable deaths were recorded. Pertussis (P=.03), dengue fever (P=.01), brucellosis (P=.001), scarlet fever (P=.02), AIDS (P<.001), syphilis (P<.001), hepatitis C (P<.001) and hepatitis E (P=.04) exhibited significant upward trends. Furthermore, measles (P<.001), bacillary and amebic dysentery (P<.001), malaria (P=.04), dengue fever (P=.006), brucellosis (P=.03), and tuberculosis (P=.003) exhibited significant seasonal patterns. We observed marked disease burden-related geographic disparities and heterogeneities. Notably, high-risk areas for various infectious diseases have remained relatively unchanged since 2005. In particular, hemorrhagic fever and brucellosis were largely concentrated in Northeast China; neonatal tetanus, typhoid and paratyphoid, Japanese encephalitis, leptospirosis, and AIDS in Southwest China; BAD in North China; schistosomiasis in Central China; anthrax, tuberculosis, and hepatitis A in Northwest China; rabies in South China; and gonorrhea in East China. However, the geographical distribution of syphilis, scarlet fever, and hepatitis E drifted from coastal to inland provinces during 2005-2020.

CONCLUSIONS

The overall infectious disease burden in China is declining; however, hepatitis C and E, bacterial infections, and sexually transmitted infections continue to multiply, many of which have spread from coastal to inland provinces.

The characteristics of bacteremia among patients with acute febrile illness requiring hospitalization in Indonesia

Blood culturing remains the "gold standard" for bloodstream infection (BSI) diagnosis, but the method is inaccessible to many developing countries due to high costs and insufficient resources. To better understand the utility of blood cultures among patients in Indonesia, a country where blood cultures are not routinely performed, we evaluated data from a previous cohort study that included blood cultures for all participants. An acute febrile illness study was conducted from July 2013 to June 2016 at eight major hospitals in seven provincial capitals in Indonesia. All participants presented with a fever, and two-sided aerobic blood cultures were performed within 48 hours of hospital admission. Positive cultures were further assessed for antimicrobial resistance (AMR) patterns. Specimens from participants with negative culture results were screened by advanced molecular and serological methods for evidence of causal pathogens. Blood cultures were performed for 1,459 of 1,464 participants, and the 70.6% (1,030) participants that were negative by dengue NS1 antigen test were included in further analysis. Bacteremia was observed in 8.9% (92) participants, with the most frequent pathogens being Salmonella enterica serovar Typhi (41) and Paratyphi A (10), Escherichia coli (14), and Staphylococcus aureus (10). Two S. Paratyphi A cases had evidence of AMR, and several E. coli cases were multidrug resistant (42.9%, 6/14) or monoresistant (14.3%, 2/14). Culture contamination was observed in 3.6% (37) cases. Molecular and serological assays identified etiological agents in participants having negative cultures, with 23.1% to 90% of cases being missed by blood cultures. Blood cultures are a valuable diagnostic tool for hospitalized patients presenting with fever. In Indonesia, pre-screening patients for the most common viral infections, such as dengue, influenza, and chikungunya viruses, would maximize the benefit to the patient while also conserving resources. Blood cultures should also be supplemented with advanced laboratory tests when available.

Immune non-interference and safety study of Vi-DT typhoid conjugate vaccine with a measles, mumps and rubella containing vaccine in 9-15 months old Nepalese infants

BACKGROUND

Typhoid fever is a common disease in developing countries especially in the Indian subcontinent and Africa. The available typhoid conjugate vaccines (TCV) have been found to be highly immunogenic in infants and children less than 2 years of age. Many countries are planning to adopt TCV in their routine EPI programs around 9 months of age when measles containing vaccines are given. Therefore, Vi-DT TCV was tested in 9-15 months aged healthy infants in Nepal to demonstrate non-interference with a measles containing vaccine.

METHODS

This was a randomized, open label, phase III study to assess the immune non-interference, safety, and reactogenicity of Vi-DT typhoid conjugate vaccine when given concomitantly with measles, mumps and rubella (MMR) vaccine. A total of 360 participants aged 9-15 months were enrolled and randomized equally into Vi-DT + MMR (180 participants) or MMR alone (180 participants) group and were evaluated for immunogenicity and safety 28 days post vaccination.

RESULTS

Using the immunogenicity set, difference between proportions (95% CI) of the Vi-DT + MMR group vs MMR alone group were -2.73% (-8.85, 3.38), -3.19% (-11.25, 4.88) and 2.91% (-3.36, 9.18) for sero-positivity rate of anti-measles, anti-mumps and anti- rubella, respectively. Only the lower bound of the range in difference of the proportions for sero-positivity rate of anti-mumps did not satisfy the non-inferiority criteria as it was above the -10% limit, which may not be of clinical significance. These results were confirmed in the per protocol set. There were no safety concerns reported from the study and both Vi-DT + MMR and MMR alone groups were comparable in terms of solicited and unsolicited adverse events .

CONCLUSIONS

Results indicated that there is non-interference of MMR vaccine with Vi-DT and Vi-DT conjugate vaccine could be considered as an addition to the EPI schedule among children at risk of contracting typhoid.

Salmonellacidal antibody response to Salmonella enterica serovar Typhi in enteric fever and after vaccination with Vi capsular polysaccharide

OBJECTIVES

Serum salmonellacidal (bactericidal) antibody could be used to detect functional capacity of antibody in patients with enteric fever and after typhoid vaccination.

METHODS

Salmonellacidal antibody response was measured by colorimetric serum salmonellacidal assay from 70 acute and 11 convalescence sera of patients infected with Salmonella Typhi and Paratyphi A and also from 15 control and 6 Vi capsular polysaccharide vaccinated volunteer's sera.

RESULTS

Sera from patients with typhoid and paratyphoid A showed significant (p < 0.05) levels of salmonellacidal antibody titer (549.9 ± 108.5 and 528.7 ± 187.3) compared with control (0.133 ± 0.1). Moreover, this titer increased significantly (p <0.05) in sera collected between 7 and 10 days and between 11 and 25 days of fever (titer 535.7 ± 119.2 and 794.6 ± 235.6) compared with sera collected from patients with fever for less than 7 days (136.4 ± 52.7). The mean titer significantly (p < 0.05) decreased to 5.5 ± 2.1 after 6-8 weeks onset of illness. Although, very low salmonellacidal titers (2.5 ± 1.5 and 2.3 ± 1.5) were detected after Vi CPS vaccine among the human volunteers, but mean titer was raised 15-fold from pre- to postvaccinated sera (0.166-2.5).

CONCLUSION

The serum salmonellacidal antibody by colorimetric salmonellacidal assay could be used to detect acute typhoidal cases and also to monitor immune response of typhoid vaccine.

Incidence of typhoid and paratyphoid fever in Bangladesh, Nepal, and Pakistan: results of the Surveillance for Enteric Fever in Asia Project

BACKGROUND

Precise enteric fever disease burden data are needed to inform prevention and control measures, including the use of newly available typhoid vaccines. We established the Surveillance for Enteric Fever in Asia Project (SEAP) to inform these strategies.

METHODS

From September, 2016, to September, 2019, we conducted prospective clinical surveillance for Salmonella enterica serotype Typhi (S Typhi) and Paratyphi (S Paratyphi) A, B, and C at health facilities in predetermined catchment areas in Dhaka, Bangladesh; Kathmandu and Kavrepalanchok, Nepal; and Karachi, Pakistan. Patients eligible for inclusion were outpatients with 3 or more consecutive days of fever in the last 7 days; inpatients with suspected or confirmed enteric fever; patients with blood culture-confirmed enteric fever from the hospital laboratories not captured by inpatient or outpatient enrolment and cases from the laboratory network; and patients with non-traumatic ileal perforation under surgical care. We used a hybrid surveillance model, pairing facility-based blood culture surveillance with community surveys of health-care use. Blood cultures were performed for enrolled patients. We calculated overall and age-specific typhoid and paratyphoid incidence estimates for each study site. Adjusted estimates accounted for the sensitivity of blood culture, the proportion of eligible individuals who consented and provided blood, the probability of care-seeking at a study facility, and the influence of wealth and education on care-seeking. We additionally calculated incidence of hospitalisation due to typhoid and paratyphoid.

FINDINGS

A total of 34 747 patients were enrolled across 23 facilitates (six tertiary hospitals, surgical wards of two additional hospitals, and 15 laboratory network sites) during the study period. Of the 34 303 blood cultures performed on enrolled patients, 8705 (26%) were positive for typhoidal Salmonella. Adjusted incidence rates of enteric fever considered patients in the six tertiary hospitals. Adjusted incidence of S Typhi, expressed per 100 000 person-years, was 913 (95% CI 765-1095) in Dhaka. In Nepal, the adjusted typhoid incidence rates were 330 (230-480) in Kathmandu and 268 (202-362) in Kavrepalanchok. In Pakistan, the adjusted incidence rates per hospital site were 176 (144-216) and 103 (85-126). The adjusted incidence rates of paratyphoid (of which all included cases were due to S Paratyphi A) were 128 (107-154) in Bangladesh, 46 (34-62) and 81 (56-118) in the Nepal sites, and 23 (19-29) and 1 (1-1) in the Pakistan sites. Adjusted incidence of hospitalisation was high across sites, and overall, 2804 (32%) of 8705 patients with blood culture-confirmed enteric fever were hospitalised.

INTERPRETATION

Across diverse communities in three south Asian countries, adjusted incidence exceeded the threshold for "high burden" of enteric fever (100 per 100 000 person-years). Incidence was highest among children, although age patterns differed across sites. The substantial disease burden identified highlights the need for control measures, including improvements to water and sanitation infrastructure and the implementation of typhoid vaccines.

FUNDING

Bill & Melinda Gates Foundation.

Etiology of acute febrile illnesses in Southern China: Findings from a two-year sentinel surveillance project, 2017–2019

Background

Southern China is at risk for arborvirus disease transmission, including Zika virus and dengue. Patients often present to clinical care with non-specific acute febrile illnesses (AFI). To better describe the etiology of AFI, we implemented a two-year AFI surveillance project at five sentinel hospitals in Yunnan and Guangdong Provinces.

Methods

Between June 2017 and August 2019, we enrolled patients between 2 and 65 years of age presenting at one sentinel hospital in Mengla County, Yunnan, and four in Jiangmen City, Guangdong, with symptoms of AFI (acute onset of fever ≥ 37.5°C within the past 7 days) without respiratory symptoms or diarrhea. Demographic, epidemiologic, and clinical information was obtained and entered into a web-based AFI surveillance database. A custom TaqMan Array card (TAC) was used to test patients’ whole blood specimens for 27 different pathogens using real-time polymerase chain reaction assays.

Results

During the two-year project period, 836 patients were enrolled; 443 patients from Mengla County and 393 patients from Jiangmen City. The median age was 33 years [range: 2–65], and most were hospitalized [641, 77%]. Of 796 patients with valid TAC results, 341 (43%) were positive for at least one of the 10 unique pathogens detected. This included 205 (26%) patients positive for dengue virus, 60 (8%) for Orientia tsutsugamushi, and 42 (5%) for Coxiella burnetii. Ten patients (1%) in Jiangmen City tested positive for malaria, 8 of whom reported recent travel outside of China. TAC results were negative for 455 (57%) patients. None of the patients had a positive TAC detection for Zika virus.

Conclusions

The project detected variability in the etiology of AFI in Southern China and highlighted the importance of differential diagnosis. Dengue, O. tsutsugamushi, and C. burnetii were the most frequently identified pathogens among enrolled AFI patients. As a non-notifiable disease, the frequent detection of C. burnetii is noteworthy and warrants additional investigation. The project provided a framework for routine surveillance for persons presenting with AFI.

Association of water, sanitation, hygiene and food practices with enteric fever in a paediatric cohort in North India

BACKGROUND

Our aim was to assess the association of water, sanitation and hygiene (WASH) and food practices with culture-confirmed enteric fever in children <15 years of age.

METHODS

We followed a cohort of 6000 children from an urban low socioeconomic neighbourhood in South Delhi for 2 years to estimate burden of culture-confirmed enteric fever. Risk ratios (RRs) were estimated to study the association between WASH practices and enteric fever. We assessed the microbiological quality of drinking water and conducted geospatial analysis to evaluate the distribution of enteric fever cases around households with contaminated drinking water.

RESULTS

A total of 5916 children in 3123 households completed survey. Piped water (82%) was the major source of household drinking water. One-third (32%) of the households treated water before consumption. Almost all households had sanitary toilets (99.9%) and 16% used shared toilets. Consumption of food from street vendors and unnamed ice creams more than once a week was observed in children from 12.7% and 38.4% households, respectively. Eighty culture-confirmed enteric fever cases were reported. The risk of enteric fever was 71% higher in children belonging to households having food from outside once a week or more (RR 1.71, 95% CI 1.00 to 2.94). The RR for enteric fever in children living in households with availability of safe drinking water was 0.75 (95% CI 0.45 to 1.26). We found that 14.8% of the households had presence of coliforms or Escherichia coli in their household drinking water. The odds of having a case of enteric fever within a 5 and 25 m buffer zone around households with contaminated drinking water were 4.07 (95% CI 0.81 to 20.5) and 1.44 (95% CI 0.69 to 3.00), respectively.

CONCLUSION

In addition to WASH practices, optimal food hygiene may have a role in urban low socioeconomic population to control enteric fever.

TRIAL REGISTRATION NUMBER

CTRI/2017/09/009719.

Risk Factors Associated with Extensively Drug-Resistant Typhoid in an Outbreak Setting of Lyari Town Karachi, Pakistan

Typhoid fever is endemic in Pakistan, with high annual incidence rates. An outbreak of extensively drug-resistant typhoid fever that first started in the Hyderabad District, Sindh Province, in November 2016 immediately spread to the entire province. We conducted an age-matched case-control study to assess the risk factors of typhoid fever in an outbreak setting of Lyari Town, Karachi. We enrolled 82 patients with blood culture-confirmed Salmonella typhi between August 2019 to December 2019, and 82 age-matched hospital and 164 age-matched community control subjects. In a matched conditional logistic regression model, consumption of meals outside the home more than once per month was associated significantly with developing culture-confirmed typhoid fever compared with no consumption of food outside the home (odds ratio, 4.11). Hygiene of the environment in which food is prepared, practices of adult food handlers, access to clean water, and food legislation play significant roles in the spread of typhoid fever.

Toward Typhoid Fever Elimination

Salmonella enterica serotype Typhi (S Typhi) causes typhoid fever and is responsible for an estimated 9 million cases and 110,000 deaths globally per annum. Typhoid fever is endemic in areas where water, sanitation, and hygiene (WaSH) infrastructure is poor. Serious complications develop in approximately 10%-15% of patients if left untreated, and this is driven by inadequate diagnostic methods and the high burden of antibiotic-resistant strains, complicating clinical management and ultimately prognosis. Asymptomatic chronic carriers, in addition to acutely infected patients, contribute to continued transmission through the shedding of the organism in the feces. The high morbidity and mortality of typhoid fever in low- and middle-income countries reinforce the need for an integrated control approach, which may ultimately lead to elimination of the disease in the 21^st century. Here we discuss the challenges faced in pursuit of typhoid fever elimination.

One Health Paradigm to Confront Zoonotic Health Threats: A Pakistan Prospective

The emergence and re-emergence of zoonotic diseases significantly impact human health, particularly those who live in impoverished areas and have close contact with domestic or wild animals. Nearly 75% of zoonotic diseases are transmitted directly from animals to humans or indirectly via vector/agent interactions between animals and humans. Growing populations, globalization, urbanization, and the interaction of the environment with humans and livestock all play roles in the emergence and spread of zoonotic diseases. "One Health" is a multidisciplinary concept aimed at improving human, animal, and environmental health, but this concept is not widely accepted in developing countries. In Pakistan, environmental, human, and animal health are severely affected due to a lack of sufficient resources. This review article provides an overview of the most common zoonotic diseases found in Pakistan and emphasizes the importance of the "One Health" concept in managing these diseases. Given the current situation, interdisciplinary research efforts are required to implement and sustain effective and long-term control measures in animal, human, and environmental health surveillance and accurate diagnostic methods.

Prevalence and antimicrobial susceptibility level of typhoid fever in Ethiopia: A systematic review and meta-analysis

Typhoid fever continues to be a health challenge in low-and middle-income countries where access to clean water and sanitation infrastructure is scarce. The non-confirmatory diagnostic method continues to hinder effective diagnosis and treatment, ensuring in a high antimicrobial resistance. This systematic review and meta-analysis aimed to estimate the pooled prevalence and antimicrobial susceptibility level of typhoid fever in Ethiopia. The review was designed based on the condition-context-population review approach. Fifteen eligible articles were identified from PubMed, Google Scholar, and Science Direct databases. Risk of bias and quality of studies were assessed using the Joanna Briggs Institute's appraisal criteria. Heterogeneity was assessed using Cochran's Q test and I2 statistics. The review protocol was registered in PROSPERO (registration number CRD42021224478). The estimated pooled prevalence of typhoid fever from blood and stool culture diagnosis was 3% (95% CI: 2%-4%, p < 0.01) (I2  = 82.25) and Widal test examination 33% (95% CI: 22%-44%) (I2  = 99.14). The sub-group analyses identified a lower detection of typhoid fever of 2% (95% CI: 1%-3%) among febrile patients compared to typhoid suspected cases of 6% (95% CI: 2%-9%). The stool culture test identified was twofold higher, value of 4% (95% CI: 2%-7%) salmonella S. Typhi infection than blood culture test of 2% (95% CI: 1%-4%). The antimicrobial susceptibility of salmonella S. Typhi for antibiotics was 94%, 80% and 65% for ceftriaxone, ciprofloxacin, and gentamycin respectively. Low susceptibility of salmonella S. Typhi isolates against nalidixic acid 22% (95% CI: 2%-46%) and chloramphenicol 11% (95% CI: 2%-20%) were observed. The diagnosis of typhoid fever was under or overestimated depending on the diagnostic modality. The Widal test which identified as nonreliable has long been used in Ethiopia for the diagnosis of salmonella S. Typhi causing high diagnosis uncertainties. Antimicrobial susceptibility of salmonella S. Typhi was low for most nationally recommended antibiotics. Ethiopian Food and Drug Authority must strengthen its continued monitoring and enhanced national antimicrobial surveillance system using the best available state-of-the-art technology and or tools to inform the rising resistance of salmonella S. Typhi towards the prescription of standard antibiotics. Finally, it is crucial to develop an evidence-based clinical decision-making support system for the diagnosis, empiric treatment and prevention of antimicrobial resistance.

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

BACKGROUND

Typhoid fever is a notifiable disease within Australia. Although studies in endemic regions give an indication of acquisition risk, many countries lack reliable data, and little is known of the absolute or relative risk in Australian travellers. By combining notified case data with travel statistics provided by the Australian Bureau of Statistics, the aim of this study was to give an indication of risk for typhoid acquisition among Australian travellers.

METHODS

Australian typhoid notifications between 1st January 2010 and 30th June 2017 were grouped by country of acquisition and age category (<15 or ≥15 years). Australian travel data were used to inform time at risk and incidence rate of Australian typhoid notifications pertaining to country and region of acquisition. Salmonella Paratyphi infections, though notifiable, were excluded as the focus was vaccine preventable illness. Data from New South Wales and Victoria were used to examine the incidence in those acquiring infection in their country of birth (COB) against travellers who did not.

RESULTS

Nine hundred twenty-three cases of typhoid were notified over the period of review, 96% of which were acquired overseas. The greatest determinant of risk was travel destination, with countries in south Asia associated with highest crude incidence rate (252 per 100 000 person-years), particularly Bangladesh. Younger age and immigrants returning to their COB were generally associated with higher risk of acquisition.

CONCLUSIONS

The risk of typhoid fever in Australian travellers to endemic regions is considerable. Immigrants returning to their COB appear to be at higher risk and it is likely that this risk extends to their traveling dependents. These findings help clinicians and public health officials to plan and advise pre-travel vaccination strategies with at-risk individuals and groups. Additional sociodemographic data collection with Australian typhoid notifications would enhance the surveillance of differing international travel risk groups leaving Australia.

Raised Amylase/Lipase levels in Enteric Fever: Prognostic marker or a sign of Pancreatitis? - Case Report

Enteric fever is a commonly diagnosed entity in developing nations. Mostly uneventful, it can sometimes manifest with a plethora of complications, including gastrointestinal hemorrhage, intestinal perforation, peritonitis, encephalopathy, and pancreatitis. We are discussing a case of enteric fever with the presentation in the form of bleeding per rectum. The patient's raised amylase and lipase levels confused the scenario as it could not be decided whether this rise was due to enteric fever or its possible but rare complication, pancreatitis. There was no radiological or clinical evidence of pancreatitis; hence the rise in the amylase and lipase levels was due to enteric fever only and not pancreatitis. Serial titers showed declining enzyme values with the improvement of patient condition. A correlation of amylase and lipase levels with enteric fever and the use of serial amylase and lipase levels as a prognostic marker for enteric fever are proposed hereby, hence, proposed.

Incidence of Enteric Fever in a Pediatric Cohort in North India: Comparison with Estimates from 20 Years Earlier

BACKGROUND

An earlier cohort in 1995-1996 showed a very high burden of typhoid in Delhi. Our aim was to estimate the current overall and age-specific incidence of culture-confirmed enteric fever among children aged 6 months to 15 years in Delhi.

METHODS

We enrolled a cohort of 6000 children aged 6 months to <14 years in South Delhi and followed them up weekly for 24 months or until 15 completed years of child age, whichever was earlier. Blood culture to confirm enteric fever was done in children with ≥3 consecutive days of fever.

RESULTS

We recorded a total of 14 650 episodes of fever in the 11 510 person-years (PY) of follow-up. A total of 81 fever episodes were positive for enteric fever. The incidence (95% confidence interval) of all enteric fever was 703.7 (560.5-874.7) per 100 000 PY. The incidences of typhoid and paratyphoid fevers were 608.1 (95% confidence interval, 481.1-768.7) and 111.7 (59.5-191.1) per 100 000 PY, respectively, highest among children aged 10-15 years.

CONCLUSIONS

Despite a 35% reduction in incidence compared with the 1995-1996 cohort, our study suggested a substantial burden of enteric fever in the population. Continued efforts to improve water, sanitation, and hygiene parameters along with implementation of novel vaccination strategies and disease surveillance can help achieve the goal of disease elimination.

Geographic Pattern of Typhoid Fever in India: A Model-Based Estimate of Cohort and Surveillance Data

Background

Typhoid fever remains a major public health problem in India. Recently, the Surveillance for Enteric Fever in India program completed a multisite surveillance study. However, data on subnational variation in typhoid fever are needed to guide the introduction of the new typhoid conjugate vaccine in India.

Methods

We applied a geospatial statistical model to estimate typhoid fever incidence across India, using data from 4 cohort studies and 6 hybrid surveillance sites from October 2017 to March 2020. We collected geocoded data from the Demographic and Health Survey in India as predictors of typhoid fever incidence. We used a log linear regression model to predict a primary outcome of typhoid incidence.

Results

We estimated a national incidence of typhoid fever in India of 360 cases (95% confidence interval [CI], 297–494) per 100 000 person-years, with an annual estimate of 4.5 million cases (95% CI, 3.7–6.1 million) and 8930 deaths (95% CI, 7360–12 260), assuming a 0.2% case-fatality rate. We found substantial geographic variation of typhoid incidence across the country, with higher incidence in southwestern states and urban centers in the north.

Conclusions

There is a large burden of typhoid fever in India with substantial heterogeneity across the country, with higher burden in urban centers.

Factors Predicting Blood Culture Positivity in Children With Enteric Fever

BACKGROUND

Blood culture, despite low sensitivity, is the gold standard for enteric fever diagnosis. Understanding predictors of blood culture positivity may help design strategies to optimize enteric fever diagnosis.

METHODS

A cohort of 6760 children aged 0.5-15 years was followed for 3 years for enteric fever with blood cultures in an automated system, for fevers >3 days. Factors affecting test positivity in fevers and participant-level predictors for culture refusals were analyzed using regression models.

RESULTS

Overall, 6097 suspected typhoid/paratyphoid fever (STF) episodes were reported, of which 5703 (93.5%) STFs had sampling for blood cultures, with 394 (6.5%) refusals. Salmonella enterica serovar Typhi/Paratyphi positivity was culture-confirmed in 3.8% (218/5703) of STF episodes. Older children (odds ratio [OR], 1.96 [95% CI, 1.39-2.77]), larger blood volume inoculated (OR, 2.82 [95% CI, 1.71-4.66]), higher temperatures during fever (OR, 3.77 [95% CI, 2.89-4.91]), and fevers diagnosed as suspected typhoid or acute undifferentiated fever (OR, 6.06 [95% CI, 3.11-11.78]) had a higher probability of culture positivity. Antibiotics before culture did not decrease culture positivity. Blood culture refusals were higher for children from wealthier households or with milder illness.

CONCLUSIONS

Performing blood cultures in older children with fever, especially those fevers with toxic presentation and increasing blood volume for inoculation are strategies to improve enteric fever detection in surveillance settings.

Typhoid in India: An Age-old Problem With an Existing Solution

Enteric fever continues to impact millions of people who lack adequate access to clean water and sanitation. The typhoid and paratyphoid fever burden in South Asia is broadly acknowledged, but current estimates of incidence, severity, and cost of illness from India are lacking. This supplement addresses this gap in our knowledge, presenting findings from two years of surveillance, conducted at multiple sites between October 2017 and February 2020, in the Surveillance for Enteric Fever in India (SEFI) network. Results provide contemporaneous evidence of high disease burden and cost of illness—the latter borne largely by patients in the absence of universal healthcare coverage in India. Against a backdrop of immediate priorities in the COVID-19 pandemic, these data are a reminder that typhoid, though often forgotten, remains a public health problem in India. Typhoid conjugate vaccines, produced by multiple Indian manufacturers, and recommended for use in high burden settings, ensure that the tools to tackle typhoid are an immediately available solution to this public health problem.

Epidemiological Investigation of Salmonella enterica Isolates in Children with Diarrhea in Chengdu, China

Background: Children with the immature intestinal immune system are prone to Salmonella infection through the fecal-oral route causing diarrhea. Non-typhoid Salmonella (NTS) is difficult to treat and eliminate due to its zoonosis. Salmonella typhi, including typhoid and paratyphoid A, B, and C, only infect humans and cause invasive infectious diseases. Salmonella typhi infection is serious and requires antibiotic treatment. The bacterial resistance caused by conventional antibacterial drugs brings great difficulties to treatment. Objectives: This study aimed to investigate the epidemiology of S. enterica in children with diarrhea in Chengdu, China. Methods: Fresh stool specimens or rectal swabs from 6656 children aged 1 day to 13 years with diarrhea were collected, cultured, identified, and tested for antimicrobial susceptibility. Analytical Profile index 20E was used for biochemical identification, and the Kirby-Bauer method was used for the bacterial sensitivity test. The whole process was conducted in accordance with the fourth edition of the National Clinical Examination procedures, and the drug sensitivity test was conducted in accordance with the Clinical and Laboratory Standards Institute 2020 guidelines. Results: A total of 649 Salmonella strains were isolated from 6656 children with suspected Salmonella infection, among which the isolation rates of NTS and S. typhi were 8.92% and 0.83%, respectively. The infection rate of S. typhimurium was the highest every year (74.88%). Salmonella infections are on the rise, especially typhimurium, Dublin, Typhi, and London. Paratyphi is unstable, presenting a phenomenon of transition and replacement (the male to female ratio:1.12:1). The infection rate was the lowest within 1 day and 6 months (P < 0.05). Salmonella mainly infected children under 3 years of age, and the positive rate was reported as 88.29%. Within June-September, the infection rate of Salmonella was the highest, with a positive rate of 72.73%. The isolated 649 Salmonella strains had good susceptibility to cefotaxime and ciprofloxacin (87.67% and 79.20%, respectively), almost no susceptibility to ampicillin, and a drug resistance rate of 92.91%. Conclusions: The typhoid and paratyphoid vaccines should be considered together, and vaccines should focus on children under 3 years of age. Antibiotics should be rationally selected according to the drug sensitivity test and disease condition.

Persisting antibody responses to Vi polysaccharide-tetanus toxoid conjugate (Typbar TCV®) vaccine up to 7 years following primary vaccination of children < 2 years of age with, or without, a booster vaccination

BACKGROUND

Serum IgG anti-Vi titers attained by 327 children 6-23 months of age immunized with Vi polysaccharide-tetanus toxoid conjugate vaccine (Typbar TCV®), of whom 193/327 received a booster dose 2 years post-primary vaccination, were previously reported.

METHODS

Anti-Vi IgG in boosted and unboosted children 3, 5, and 7 years post-primary immunization were monitored using three different enzyme-linked immunosorbent assays (ELISAs): Vacczyme™ kit ELISA (all specimens); "Szu" ELISA (all specimens), and National Institute of Biological Standards NIBSC ELISA (subset). Endpoints analyzed included: persisting seroconversion (titer remaining ≥ 4-fold above baseline), geometric mean titer (GMT), geometric mean-fold rise post-vaccination, and percent exhibiting putative protective anti-Vi level (≥2 µg_Szu/ml) using Szu method and National Institutes of Health IgG reference standard. In assessing the persistence of elevated anti-Vi titers stimulated by Typbar-TCV®, four subgroups were compared based on whether or not the initially enrolled children were boosted on day 720 and whether they provided serum on all key timepoints, or if they missed one or more timepoints: i) Among boosted participants, an "All Specimens Cohort" (ASC) comprised 86 children who provided sera on days 42, 720 (booster), 762 (42 days post-booster), 1095, 1825 and 2555, to define kinetics of the Vi antibody response in a fully compliant cohort of boosted children monitored over seven years; ii) Among non-boosted subjects, a compliant All Specimens Cohort of 25 children provided sera on days 0, 42, 720, 1095, 1825, and 2555; iii) Among boosted children, an "Any Available Specimen" (AAS) subgroup consisted of boosted children who provided sera on days 0, 42, and 720 days and also on one or more of days 762, 1095, 1825, or 2555 but not on all those time points; iv) Among the non-boosted subjects, there was also an Any Available Specimen subgroup of 47 children who provided sera on days 0 and 42, of whom 41 subsequently contributed sera on one or more of days 1095, 1825 and 2555.

RESULTS

Vacczyme™ GMTs among boosted ASC children (N = 86) increased significantly on day 762, and remained 32-fold, 14-fold, and 10-fold over baseline at 3, 5 and 7 years; among unboosted ASC children (N = 25), GMTs remained 21-fold, 8-fold and 5-fold over baseline, respectively. Post-primary vaccination, 72% and 44% of unboosted ASC subjects (N = 25) exhibited persisting seroconversion by Vacczyme™ at 5 and 7 years, respectively; the corresponding numbers for ASC boosted subjects were 84% and 71%. Amongst the four sub-groups, boosted subjects showed higher prevalence of persisting seroconversion at most time points with the gap widening by 7th year, though not statistically significant (except 3rd year). Tested by Szu and also NIBSC ELISAs, 92-100% of unboosted ASC children showed persisting seroconversion at 7 years with 100% also exceeding the Szu protective threshold.

CONCLUSION

To extend protection, administering a booster of Typbar TCV® to children ∼5 years after their primary dose, i.e., coinciding with school entry, may be advisable. Typbar TCV® is presently the only WHO pre-qualified Vi conjugate vaccine with reported efficacy, effectiveness, and long-term immunogenicity findings.

The potential roles of pharmacy medication sales data to augment the syndromic surveillance system in response to COVID-19 and preparedness for other future infectious disease outbreaks in Indonesia

BACKGROUND

Indonesia faces a continuous threat from communicable disease outbreaks. The current COVID-19 outbreak, the previous one of SARS, and many other infectious outbreaks encountered in the country warn of the need to develop comprehensive early warning systems to enable timely health responses in the long run. In this article, we argue that over the counter medication sales data at community pharmacies in Indonesia can potentially augment and increase the detection power of the current syndromic surveillance system, particularly in dealing with COVID-19 and other future infectious disease outbreaks in the country.

MAIN BODY

This article discusses the experience of other countries in employing pharmacy medication sales data to serve as potential syndromic surveillance platform and contribute to pandemic responses. We argue why it is worth considering utilising medication sales data from pharmacies in Indonesia to support the current surveillance system which enables the provision of early warnings of disease outbreaks. We then discuss the potential challenges of operationalising these data and suggest a way forward for the development and implementation of the syndromic surveillance system at community pharmacy settings in Indonesia.

CONCLUSION

While there are several challenges in developing a workable system in Indonesia that need to be addressed, introducing a syndromic surveillance system using pharmacy-setting medication sales data is worth investigating in the country.

Massive Gastrointestinal Hemorrhage Secondary to Typhoid Fever

Typhoid fever is caused by Salmonella typhi, a gram-negative organism. The disease usually presents with high-grade fever, abdominal pain, and diarrhea. Gastrointestinal hemorrhage is a frequent complication of the disease. However, adequate treatment with antibiotics has lowered the rate of complications. We present the case of a 21-year-old male who was admitted to the hospital with high-grade fever and per rectal bleeding. A few hours after admission, the patient had episodes of massive per rectal bleeding which resulted in hemodynamic instability. The bleeding was then successfully controlled with endoscopic hemoclipping. Concurrently, his blood culture results showed growth of Salmonella typhi for which antibiotic therapy was initiated, and the patient's condition improved thereafter. This report highlights the rare occurrence of massive lower gastrointestinal bleeding in patients with typhoid fever. It also signifies the use of endoscopic therapy with endoclips for the management of massive lower gastrointestinal bleeding. 

Association of Antibody-Dependent Neutrophil Phagocytosis With Distinct Antibody Glycosylation Profiles Following Typhoid Vaccination

Typhoid Vi-conjugate vaccines (Vi-TCV) have been developed to control typhoid fever in children in endemic regions. Previously, in a human challenge model of typhoid, Vi-TCV was administered prior to deliberate ingestion of Salmonella Typhi by healthy adult volunteers in the UK. Vi-specific antibody-dependent neutrophil phagocytosis (ADNP) was associated with protection against enteric fever in this model, but it is not known if ADNP is induced by vaccination of children. We measured ADNP in a cohort of Nepalese children receiving a Vi-TCV in a field study to investigate whether functional antibody responses were also present in children in an endemic setting. Furthermore, we investigated relationships between the functional antibody measures and other properties of the antibody response, including Vi-IgG and IgA titres, and Fc region glycosylation. Antibody-dependent neutrophil phagocytosis significantly increased in children aged 9 months to 15 years between the day of vaccination and 28 days following administration of Vi-TCV (D28). The magnitude of ADNP was also comparable with the levels of ADNP induced by plasma from vaccinated UK adults. Neither IgG nor IgA antibody titres significantly correlated with ADNP scores at D28; however, increased vaccine-induced ADNP was associated with decreased levels of IgG1 sialylation. These data suggest that vaccination with Vi-TCV produces functional antibody responses in children, which associate with specific glycosylation patterns of the Fc region.

A review of clinical profile, complications and antibiotic susceptibility pattern of extensively drug-resistant (XDR) Salmonella Typhi isolates in children in Karachi

Background

Enteric fever is a systemic infection caused by Salmonella enterica serovar Typhi and Salmonella enterica serovar Paratyphi A, B, and C. There is an emergence of Typhoid fever caused by extensively drug-resistant Salmonella Typhi strain called XDR S.Typhi. This strain is resistant to recommended first-line antibiotics and cephalosporins. WHO estimated 5274 cases of XDR S.Typhi in Karachi from November 2016 to December 2019. This study aims to determine clinical course, complications and response to treatment of XDR S.Typhi among the pediatric population coming to Indus Hospital.

Method

We reviewed the records of children who had culture-proven XDR S.Typhi infection at Indus Hospital from July 2017 to December 2018. A pre-designed data abstraction form was used to record information about seasonality, demographic details, clinical features and course, treatment, complications and outcomes of the cases of XDR S.Typhi.

Results

The records of 680 children were reviewed. The median (IQR) age of the patients was 5 (2–8) years. More than half (n = 391, 57.5%) of the patients were males. The outcomes were recorded in 270 (40%) patients. Out of these, 234 (86.7%) children got cured within 14 days, while a delayed response to antibiotics was noted in 32 (11.9%) children. Seventy-six (29%) children recovered on a combination of meropenem and azithromycin, 72 (27%) got cured on azithromycin alone, while 15 (6%) responded to meropenem alone.

Conclusion

Our review indicated that children under 5 years of age were affected more with XDR S.Typhi. Azithromycin alone or in combination with meropenem were effective antibiotics for treating XDR S.Typhi in children.

A genomic snapshot of Salmonella enterica serovar Typhi in Colombia

Little is known about the genetic diversity of Salmonella enterica serovar Typhi (S. Typhi) circulating in Latin America. It has been observed that typhoid fever is still endemic in this part of the world; however, a lack of standardized blood culture surveillance across Latin American makes estimating the true disease burden problematic. The Colombian National Health Service established a surveillance system for tracking bacterial pathogens, including S. Typhi, in 2006. Here, we characterized 77 representative Colombian S. Typhi isolates collected between 1997 and 2018 using pulse field gel electrophoresis (PFGE; the accepted genotyping method in Latin America) and whole genome sequencing (WGS). We found that the main S. Typhi clades circulating in Colombia were clades 2.5 and 3.5. Notably, the sequenced S. Typhi isolates from Colombia were closely related in a global phylogeny. Consequently, these data suggest that these are endemic clades circulating in Colombia. We found that AMR in S. Typhi in Colombia was uncommon, with a small subset of organisms exhibiting mutations associated with reduced susceptibility to fluoroquinolones. This is the first time that S. Typhi isolated from Colombia have been characterized by WGS, and after comparing these data with those generated using PFGE, we conclude that PFGE is unsuitable for tracking S. Typhi clones and mapping transmission. The genetic diversity of pathogens such as S. Typhi is limited in Latin America and should be targeted for future surveillance studies incorporating WGS.

Prevalence and antimicrobial resistance phenotypes of Salmonella species recovered at various stages of broiler operations in Hathazari, Bangladesh

Background and Aim: Dissemination of multidrug-resistant (MDR) Salmonella through food chains has serious health implications, with higher rates of morbidity and mortality. Broiler meat remains a major reservoir of Salmonella contamination. The lack of proper hygiene in local broiler operations has, therefore, prompted this research into the assessment of Salmonella contamination in local shops and associated antimicrobial resistance (AMR) phenotypes. Materials and Methods: A total of 55 broiler samples including skin, meat, and swab samples from chopping and dressing sites were included in the study. The samples were collected from broiler shops in Hathazari, Bangladesh, and screened for the presence of Salmonella strains using culture-based methods. The isolates were biochemically characterized and further tested for AMR to eight common antibiotics using the disk diffusion technique. Results: Salmonella contaminations were identified in 29% (16/55) of the broiler samples. Swab samples collected from the chopping sites appeared to be contaminated in higher proportions (33%) than those collected from the dressing areas (25%). On the other hand, the skin samples (50%) were detected with a higher percentage of contamination than the meat samples (25%). All Salmonella isolates showed resistance toward at least one of the eight antibiotics used. Although none of the isolates was resistant to all antibiotics, 18.75% showed resistance to a maximum of seven antibiotics. Resistance to nalidixic acid was most prevalent (87.5%), followed by sulfamethoxazole-trimethoprim (81.25%), erythromycin (81.25%), tetracycline (75%), streptomycin (56.25%), ampicillin-clavulanic acid (50%), chloramphenicol (43.75%), and cefotaxime (18.75%). The resistance patterns of the isolates were found to be highly diverse. The most frequently observed pattern was the following: Ampicillin-clavulanic acid-sulfamethoxazole-trimethoprim-nalidixic acid-tetracycline-chloramphenicol-streptomycin-erythromycin. Conclusion: The relatively high prevalence of MDR strains in the samples underlies an urgent need for surveillance and control measures concerning hygiene and antibiotic use in local broiler operations.

Salmonella Typhi from Northwest Pakistan: Molecular Strain Typing and Drug Resistance Signature

Objective: To determine the molecular strain typing and drug resistance pattern of Salmonella enterica serovar Typhi prevalent in Northwest Pakistan. Methodology: A total of 2,138 blood samples of suspected typhoid patients from Northwest Pakistan were collected followed by identification of Salmonella Typhi through biochemical, serological, and species-specific fliC-d gene amplification. These isolates were typed by variable-number tandem repeat (VNTR) profiling and investigated for drug resistance. Results: The overall prevalence of Salmonella Typhi was found to be 8.8% (n = 189). Thirty different VNTR strain types of Salmonella Typhi were detected and the most prevalent strain types were T1 and T4, whereas T27 was less prevalent strain. Among the 189 isolates 175 (92.5%) isolates were multidrug resistant, whereas 12 (5.8%) isolates were extensively drug resistant. Resistance to imipenem in Salmonella Typhi was not observed. Most of the isolates have genes encoding for resistance to fluoroquinolones, including gyrA (n = 164), gyrB (n = 160), parC (n = 164), parE (n = 160), ac(6')-ib-cr (n = 163), qnrS (n = 15), and qnrB (n = 3). Similarly, chloramphinicol (cat; n = 147), azithromycin (msrA; n = 3), and co-trimoxazole (dfrA7; n = 145) resistance genes were detected among Salmonella Typhi isolates. Conclusion: In this study, T1 and T4 type Salmonella Typhi strains were predominantly prevalent in Northwest Pakistan. Antibiotic resistance among Salmonella Typhi isolates were observed. Findings of the study would be helpful to devise an appropriate antibiotic policy to control the emergence of drug-resistant Salmonella Typhi in Pakistan.

Exploring willingness to participate in future Human Infection Studies in Lusaka, Zambia: A nested qualitative exploratory study

Human Infection Studies (HIC) involve intentional infection of volunteers with a challenge agent or pathogen with the aim of understanding and developing vaccines as well as understanding the disease pathophysiology in a well-controlled environment. Though Africa carries the highest burden of vaccine-preventable diseases, the region is only now being primed to conduct HIC relevant to its population. Given the imminent introduction of HIC in Zambia, we sought to understand potential participants' willingness to volunteer for such studies. We used a qualitative exploratory approach to understand the potential participants' perceptions on willingness to participate in HIC using the example of typhoid. Healthy adults, recruited using random selection and purposive sampling from higher learning institutions in Lusaka, participated in 15 in-depth interviews (IDIs) and 5 Focus Group Discussions (FGDs) respectively. Participants considered typhoid a serious disease with potential for life-long consequences and death. After sharing audio-visual materials introducing the concepts of HIC, some participants expressed open willingness to participate or alternatively the need to consult parents and professors, and expressed fear of death and illness. Though willing to be quarantined for up to six months, participants expressed concerns regarding separation from family and duties, having insufficient information to decide, inadequate access to care, severe disease, life-long injury or side-effects, death, and vaccine failure. These concerns along with possibility of underlying conditions that compromise individual immunity, competing priorities, parental refusal, and distrust of study or vaccine efficacy could lead to refusal to participate. Reasons for willingness to participate included monetary compensation, altruism and being part of a team that comes up with a vaccine. Though afraid of deliberate typhoid infection, potential participants are willing to consider participation if given adequate information, time to consult trusted persons, compensation and assurance of adequate care.

Challenges and opportunities in setting up a phase III vaccine clinical trial in resource limited settings: Experience from Nepal

Clinical trials are complicated, time-consuming and costly. From the initial screening, informed consent and recruitment of the participants’ to study completion, the sponsor must undertake a wide array of complex and closely monitored operations, complying with international standards for human subject research and local requirements. Conducting these studies in an underdeveloped country, with limited resources, infrastructure, and experience with regulated clinical trials adds to this complexity. The initial site selection, set up and preparatory activities for the clinical trial are crucial to minimizing the risks to both participants and to successful completion during the subsequent study execution.

In this paper, we describe the experience and lessons learned of building clinical trial site capacity in terms of infrastructure and human resource development for a Phase III vaccine clinical trial. We believe that sharing the experience of setting up a clinical trial in a resource-limited country will enable other entities contemplating clinical research in these countries, to prepare and plan ahead, to minimize the impact of barriers, and to contribute to bringing more studies to the countries where people live with the burden of vaccine-preventable, poverty-associated diseases.

A Rare Case of Salmonella meningitis and Hemophagocytic Lymphohistiocytosis

Enteric fever is a common infectious disease of the tropical world. Common age group involved is children aged between 5 and 10 years. In addition to diarrhea, it may lead to extraintestinal infections including aseptic meningitis, hepatitis, cholecystitis, acute abdomen, intestinal perforation, pneumonia, psychosis, and ataxia. Hematologic complications leading to hemophagocytosis have a prevalence of < 1%. Salmonella meningitis has an incidence of 6% with poor prognosis neurological sequelae. We report a rare case of enteric fever that presented with hemophagocytic syndrome and S. meningitis. Response to third-generation cephalosporins is dramatic, eventually giving good prognosis.