Nutcracker syndrome unveiled by severe Typhoid fever: A rare case report

Typhoid fever, caused by Salmonella Typhi, is a severe bacterial infection prevalent in developing countries, and can result in life-threatening complications if untreated. Nutcracker Syndrome is a rare vascular disorder involving compression of the left renal vein between the aorta and the superior mesenteric artery. It can lead to various symptoms and poses diagnostic and management challenges. We present a case study of a patient diagnosed with typhoid fever in a Unit of Critical Emergency Care. Coincidentally, the evaluation through CT-scan revealed the presence of Nutcracker Syndrome. This report underscores the incidental discovery of Nutcracker Syndrome during the assessment of a patient with typhoid fever in a critical emergency care setting.

Typhoid Fever Presenting with Ileal Perforation and Gastric Perforation

Typhoid fever is caused by Salmonella typhi and Salmonella paratyphi. It is a disease of developing countries and is seen among people of low socio-economic status. Patients can develop complications like typhoid intestinal perforation which is associated with higher mortality. A 15-year-old female presented to the emergency pediatric unit with fever, abdominal pain and abdominal distension. She was septic, in respiratory distress, and had marked generalized abdominal tenderness with guarding. An assessment of generalized peritonitis secondary to typhoid intestinal perforation was made. She had exploratory laparotomy with intra-operative findings of ileal perforation and gastric perforation. She had repair of the intestinal and gastric perforations. Our patient presented late with concurrent use of NSAIDs and overwhelming sepsis which likely contributed to the gastric perforation as this is not a usual finding in patients with typhoid intestinal perforation. Gastric perforation is an unusual finding in patients with typhoid intestinal perforation. Typhoid fever and its complications can be easily prevented by the provision of safe water, proper facilities for sanitation, and practicing good hygiene.

Typhoid and Non-Typhoid Salmonellosis Related Mortality in Iran, National Data from the Ministry of Health

Background

Despite the declining trend, salmonellosis is still an important preventable cause of death in Iran and the world, especially in certain age and occupational subgroups, and the need for preventive measures, especially raising awareness of at-risk groups, is necessary.

Methods

Data were obtained from the Ministry of Health covering the years 2013 to 2019. The data were then stratified by year, season, month, and province of death as well as sex, age group, belonging to rural vs. urban communities and cause of death and were then analyzed using SPSS to report differences in age, sex, seasonal patterns, and spatial distribution.

Results

Non-typhoid salmonellosis (NTS) and typhoid were recorded as the cause of 800 and 32 deaths, respectively, with the highest number in 2015 and 2013. Septicemia was the cause of 87.3% of deaths due to NTS, whereas typhoid was the cause of 62.5% of its respective cases. The highest percentage of death related to both occurred in spring (P<0.001). NTS mortality rates were higher in the 70-80 and 80-90 age groups, while typhoid mortality was greatest in the under 10 yr age group. NTS mortality was higher in urban while typhoid mortality was higher in rural areas (P<0.001). Most deaths occurred in Ardabil, Sistan and Baluchistan and Khorasan Razavi provinces and Sistan and Baluchistan, West Azerbaijan and Khorasan Razavi related to NTS and typhoid, respectively.

Conclusion

Salmonella remains a preventable cause of death, especially among the elderly and children, the data gathered in this study provides important information for priority setting in specific subpopulations and food safety policy.

Typhoid fever, complicated by syncope due to relative bradycardia: A case report

In a United Nations (UN) staff member headquarters in South Sudan, we present a rare typhoid fever complicated by syncope due to relative bradycardia. A 25-year-old male presented to our hospital with a high fever, diarrhea, and no vomiting. He had no substantial medical background. He was diagnosed with an unspecified digestive disorder and received initial treatment. Two syncope episodes were recorded in the Level 1 hospital. He was referred to our hospital at the 30th hour and the third fainting occurred. Electrocardiogram showed bradycardia with a heart rate of 40 beats/min. The atropine test was negative; the initial diagnosis was sinus sickness syndrome. Microbiology tests later suggested typhoid infection. Then, the diagnosis changed to relative bradycardia caused by Salmonella typhi; and he was orally treated with the third-generation Quinolone antibiotic. He significantly improved and got discharged on the seventh day. In conclusion, typhoid remains a real and present threat to UN staff and civilians in South Sudan.

Cost-effectiveness analysis of typhoid conjugate vaccines in an outbreak setting: a modeling study

BACKGROUND

Several prolonged typhoid fever epidemics have been reported since 2010 throughout eastern and southern Africa, including Malawi, caused by multidrug-resistant Salmonella Typhi. The World Health Organization recommends the use of typhoid conjugate vaccines (TCVs) in outbreak settings; however, current data are limited on how and when TCVs might be introduced in response to outbreaks.

METHODOLOGY

We developed a stochastic model of typhoid transmission fitted to data from Queen Elizabeth Central Hospital in Blantyre, Malawi from January 1996 to February 2015. We used the model to evaluate the cost-effectiveness of vaccination strategies over a 10-year time horizon in three scenarios: (1) when an outbreak is likely to occur; (2) when an outbreak is unlikely to occur within the next ten years; and (3) when an outbreak has already occurred and is unlikely to occur again. We considered three vaccination strategies compared to the status quo of no vaccination: (a) preventative routine vaccination at 9 months of age; (b) preventative routine vaccination plus a catch-up campaign to 15 years of age; and (c) reactive vaccination with a catch-up campaign to age 15 (for Scenario 1). We also explored variations in outbreak definitions, delays in implementation of reactive vaccination, and the timing of preventive vaccination relative to the outbreak.

RESULTS

Assuming an outbreak occurs within 10 years, we estimated that the various vaccination strategies would prevent a median of 15-60% of disability-adjusted life-years (DALYs). Reactive vaccination was the preferred strategy for WTP values of $0-300 per DALY averted. For WTP values > $300, introduction of preventative routine TCV immunization with a catch-up campaign was the preferred strategy. Routine vaccination with a catch-up campaign was cost-effective for WTP values above $890 per DALY averted if no outbreak occurs and > $140 per DALY averted if implemented after the outbreak has already occurred.

CONCLUSIONS

Countries for which the spread of antimicrobial resistance is likely to lead to outbreaks of typhoid fever should consider TCV introduction. Reactive vaccination can be a cost-effective strategy, but only if delays in vaccine deployment are minimal; otherwise, introduction of preventive routine immunization with a catch-up campaign is the preferred strategy.

Travel-associated extensively drug-resistant typhoid fever: a case series to inform management in non-endemic regions

BACKGROUND

Extensively drug-resistant (XDR) typhoid fever is a threat to travelers to Pakistan. We describe a multicontinental case series of travel-acquired XDR typhoid fever to demonstrate the global spread of the problem and encourage preventive interventions as well as appropriate empiric antimicrobial use.

METHODS

Cases were extracted from the GeoSentinel database, microbiologic laboratory records of two large hospitals in Toronto, Canada, and by invitation to TropNet sites. All isolates were confirmed XDR Salmonella enterica serovar Typhi (Salmonella typhi), with resistance to ampicillin, ceftriaxone, ciprofloxacin and trimethoprim-sulfamethoxazole.

RESULTS

Seventeen cases were identified in Canada (10), USA (2), Spain (2), Italy (1), Australia (1) and Norway (1). Patients under 18 years represented 71% (12/17) of cases, and all patients travelled to Pakistan to visit friends or relatives. Only one patient is known to have been vaccinated. Predominant symptoms were fever, abdominal pain, vomiting and diarrhoea. Antimicrobial therapy was started on Day 1 of presentation in 75% (12/16) of patients, and transition to a carbapenem or azithromycin occurred a median of 2 days after blood culture was drawn. Antimicrobial susceptibilities were consistent with the XDR S. typhi phenotype, and whole genome sequencing on three isolates confirmed their belonging to the XDR variant of the H58 clade.

CONCLUSIONS

XDR typhoid fever is a particular risk for travelers to Pakistan, and empiric use of a carbapenem or azithromycin should be considered. Pre-travel typhoid vaccination and counseling are necessary and urgent interventions, especially for visiting friends and relatives travelers. Ongoing sentinel surveillance of XDR typhoid fever is needed to understand changing epidemiology.

Comparison of model predictions of typhoid conjugate vaccine public health impact and cost-effectiveness

Models are useful to inform policy decisions on typhoid conjugate vaccine (TCV) deployment in endemic settings. However, methodological choices can influence model-predicted outcomes. To provide robust estimates for the potential public health impact of TCVs that account for structural model differences, we compared four dynamic and one static mathematical model of typhoid transmission and vaccine impact. All models were fitted to a common dataset of age-specific typhoid fever cases in Kolkata, India. We evaluated three TCV strategies: no vaccination, routine vaccination at 9 months of age, and routine vaccination at 9 months with a one-time catch-up campaign (ages 9 months to 15 years). The primary outcome was the predicted percent reduction in symptomatic typhoid cases over 10 years after vaccine introduction. For three models with economic analyses (Models A-C), we also compared the incremental cost-effectiveness ratios (ICERs), calculated as the incremental cost (US$) per disability-adjusted life-year (DALY) averted. Routine vaccination was predicted to reduce symptomatic cases by 10-46 % over a 10-year time horizon under an optimistic scenario (95 % initial vaccine efficacy and 19-year mean duration of protection), and by 2-16 % under a pessimistic scenario (82 % initial efficacy and 6-year mean protection). Adding a catch-up campaign predicted a reduction in incidence of 36-90 % and 6-35 % in the optimistic and pessimistic scenarios, respectively. Vaccine impact was predicted to decrease as the relative contribution of chronic carriers to transmission increased. Models A-C all predicted routine vaccination with or without a catch-up campaign to be cost-effective compared to no vaccination, with ICERs varying from $95-789 per DALY averted; two models predicted the ICER of routine vaccination alone to be greater than with the addition of catch-up campaign. Despite differences in model-predicted vaccine impact and cost-effectiveness, routine vaccination plus a catch-up campaign is likely to be impactful and cost-effective in high incidence settings such as Kolkata.

Obstructing Salmonella typhi's virulence in eukaryotic cells through design of its SipB protein antagonists

Objective

Typhoid fever, a disease caused by Salmonella typhi, is a leading cause of morbidity and mortality, particularly in developing nations. The evolution of resistance mechanisms to existing antibiotics has necessitated a search for newer drug candidates. This study used computer aided drug design techniques to design novel antibiotics that function by antagonizing SipB, an effector protein of the bacterium that is responsible for its pathogenicity and virulence in eukaryotic host cells.

Methods

A data set of 32 bioactive molecules with established antibacterial activity against S. typhi was retrieved from the PubChem data base; optimized through a DFT approach in Spartan 14 software; and further subjected to QSAR modeling in BIOVIA-Accelrys Material Studio. The validated model (R² = 0.80, R² _Adj = 0.78, Q² _LOO = 0.74, R² _pred = 0.54, lack of fit = 0.07) revealed the dominant influence of MATS6c and E3p descriptors on the observed antibacterial activity of the compounds. Information from the model was used to optimize the structures of selected lead compounds in the data set, thus leading to the design of a highly potent set of novel analogues denoted D-1, D-2 and D-3.

Results

The predicted MIC values of D-1, D-2 and D-3 were 1.03, 0.73 and 0.30 μg/mL, respectively. Furthermore, molecular docking studies on these novel ligands against the active sites of SipB revealed binding energy values of -8.0, -7.7 and -7.7 kcal/mol for D-1, D-2 and D-3, respectively. These values were better than the -7.0 kcal/mol recorded for ciprofloxacin, the reference antibiotic used herein for quality assurance. In addition, drug-likeness and ADMET evaluation of the designed compounds revealed that they are orally bioavailable and exhibit excellent pharmacokinetic and toxicological profiles.

Conclusion

The current findings may provide a roadmap for the discovery of more potent antibiotics against S. typhi.

Molecular diagnostics and next-generation sequencing reveal real etiological characteristics of invasive Salmonella infection in febrile illness in Freetown, Sierra Leone

Invasive Salmonella infection, which can cause typhoid/paratyphoid fever and invasive non-typhoidal salmonellosis, is a public health burden in Africa. Accurate diagnosis and etiological characterization are required to conduct prevalence and risk estimations for Salmonella infection; however, the utilization of optimal techniques and surveillance data are still insufficient. In this study, we performed a laboratory-based survey in Freetown, which is the biggest city in Sierra Leone with a high burden of typhoid fever, by using blood culture and molecular methods but not the Widal test, to estimate the prevalence and aetiology of invasive Salmonella infection among fever patients. We found a very low prevalence of typhoid fever in patients with fever during the investigation period, and this prevalence was clearly overestimated by the Widal test. Genome sequencing of the S. Typhi isolate from this work revealed that the strain carried multiple antibiotic resistance genes, and an epidemic clone that has existed in West Africa for years was also detected in Sierra Leone. By using metagenomic sequencing, one patient with invasive non-typhoidal salmonellosis was identified as having bacterial co-infections. Our data highlight that Salmonella surveillance based on accurate laboratory diagnosis and genome sequencing needs to be strengthened to provide a better estimation of the real epidemics and enable potential risk assessment by etiological analysis in Africa. Even in a laboratory with only basic equipment, it is possible to conduct next-generation sequencing for pathogen discovery in bloodstream infections and to determine the etiological characteristics of pathogene without complex combinations of laboratory methods.

Hotspots sequences of gyrA, gyrB, parC, and parE genes encoded for fluoroquinolones resistance from local Salmonella Typhi strains in Jakarta

Background

Infection of Salmonella enterica subsp. enterica serovar Typhi is the primary etiology of typhoid fever globally and is common in many developing countries, especially those with dense populations and poor environmental sanitation. Antibiotic fluoroquinolones were used for the treatment in the 1980s due to the resistance to the first-line antibiotics. However, many cases of treatment failure of fluoroquinolones in typhoidal patients have been reported from numerous countries in Asia, Europe, Africa, and America. Mutations in quinolone resistance determining regions (QRDR) genes, gyrA, gyrB, parC, and parE, are found in fluoroquinolone-resistant Salmonella Typhi. Contrast reports came from the S. Typhi isolates in Indonesia, mainly Jakarta and the surroundings, obtained from patients with typhoid fever, with good sensitivity to the fluoroquinolones, i.e., nalidixic acid, ciprofloxacin, moxifloxacin, and levofloxacin. The present study, therefore, aimed to identify the hotspot sequences of gyrA, gyrB, parC, and parE genes of the local S. Typhi strains based on their susceptibility to fluoroquinolones from patients with typhoid fever in Jakarta and its satellite cities.

Results

A total of 28 isolates were identified as S. Typhi. All isolates were susceptible to nalidixic acid, levofloxacin, and moxifloxacin. Twenty-seven isolates (96.4%) were susceptible to ciprofloxacin, with one isolate (3.6%) being intermediate. The hotspot sequences of gyrA, gyrB, parC, and parE genes from all isolates were identical to the fluoroquinolone-sensitive reference sequence Salmonella enterica subsp. enterica serovar Typhi Ty2 (NCBI GenBank AE014613.1), including the isolate with intermediate susceptibility. The mutation was not found, and amino acid deduced from all hotspots in susceptible and intermediate isolates showed no replacement in all reported codons.

Conclusions

This study showed that the local S. Typhi strains from Jakarta and surroundings were susceptible to fluoroquinolones (nalidixic acid, ciprofloxacin, levofloxacin, and moxifloxacin), and the hotspot sequences of the gyrA, gyrB, parC, and parE genes were all identical to the reference sequence. Thus, the hotspot sequences of the gyrA, gyrB, parC, and parE genes seemingly were conserved in Jakarta’s local S. Typhi strains and could be considered wild type. The phenotypic susceptibility was consistent with the genotypic characteristic without non-synonymous mutations associated with drug resistance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02666-z.

Clinical profiles and antimicrobial resistance patterns of invasive Salmonella infections in children in China

Invasive Salmonella infections result in a significant burden of disease including morbidity, mortality, and financial cost in many countries. Besides typhoid fever, the clinical impact of non-typhoid Salmonella infections is increasingly recognized with the improvement of laboratory detection capacity and techniques. A retrospective multicenter study was conducted to analyze the clinical profiles and antimicrobial resistance patterns of invasive Salmonella infections in hospitalized children in China during 2016–2018. A total of 130 children with invasive Salmonella infections were included with the median age of 12 months (range: 1–144 months). Seventy-nine percent of cases occurred between May and October. Pneumonia was the most common comorbidity in 33 (25.4%) patients. Meningitis and septic arthritis caused by nontyphoidal Salmonella (NTS) infections occurred in 12 (9.2%) patients and 5 (3.8%) patients. Patients < 12 months (OR: 16.04) and with septic shock (OR: 23.4), vomit (OR: 13.33), convulsion (OR: 15.86), C-reactive protein (CRP) ≥ 40 g/L (OR: 5.56), and a higher level of procalcitonin (PCT) (OR: 1.05) on admission were statistically associated to an increased risk of developing meningitis. Compared to 114 patients with NTS infections, 16 patients with typhoid fever presented with higher levels of CRP and PCT (P < 0.05). The rates of resistance to ampicillin, sulfamethoxazole/trimethoprim, ciprofloxacin, and ceftriaxone among Salmonella Typhi and NTS isolates were 50% vs 57.3%, 9.1% vs 24.8%, 0% vs 11.2%, and 0% vs 9.9%, respectively. NTS has been the major cause of invasive Salmonella infections in Chinese children and can result in severe diseases. Antimicrobial resistance among NTS was more common.

Effectiveness of typhoid conjugate vaccine in Zimbabwe used in response to an outbreak among children and young adults: A matched case control study

BACKGROUND

Zimbabwe suffers from regular outbreaks of typhoid fever (TF), worse since 2017. Most cases were in Harare and a vaccination campaign with Typhoid Conjugate Vaccine (TCV) was conducted in March 2019. The vaccine effectiveness (VE) was assessed against culture-confirmed S. Typhi in children six months to 15 years and in individuals six months to 45 years in Harare.

METHODS

A matched case-control study was conducted in three urban suburbs of Harare targeted by the TCV vaccination campaign. Suspected TF cases were enrolled prospectively in four health facilities and were matched to facility (1:1) and community (1:5) controls.

FINDINGS

Of 504 suspected cases from July 2019 to March 2020, 148 laboratory-confirmed TF cases and 153 controls confirmed-negative were identified. One hundred and five (47 aged six months to 15 years) cases were age, sex, and residence matched with 105 facility-based controls while 96 cases were matched 1:5 by age, sex, and immediate-neighbour with 229 community controls. The adjusted VE against confirmed TF was 75% (95%CI: 1-94, p = 0.049) compared to facility controls, and 84% (95%CI: 57-94, p < 0.001) compared to community controls in individuals six months to 15 years. The adjusted VE against confirmed TF was 46% (95%CI: 26-77, p = 0.153) compared to facility controls, and 67% (95%CI: 35-83, p = 0.002) compared to community controls six months to 45 years old.

INTERPRETATION

This study confirms that one vaccine dose of TCV is effective to control TF in children between six months and 15 years old in an African setting.

A Phase 3, Multicenter, Randomized, Controlled Trial to Evaluate Immune Equivalence and Safety of Multidose and Single-dose Formulations of Vi-DT Typhoid Conjugate Vaccine in Healthy Filipino Individuals 6 Months to 45 Years of Age

Trial Design

Phase 3, randomized, controlled, multicenter, equivalence trial.

Methods

Recruitment of participants occurred between 04Februray2020 and 15July2020 at four centers in the Philippines: University of the East - Ramon Magsaysay Memorial Medical Center Inc., Quezon City; University of Philippines Manila - National Institute of Health, Ermita Manila; Asian Hospital and Medical Center, Metro Manila, Philippines Study; and Medical Research Unit, Tropical Disease Foundation, Makati City, Metro Manila, Philippines.

Participants

1800 adults and children 6-months to 45-years of age.

Interventions

Participants received a single injection of multidose (MD) or single dose (SD) Vi-DT as test vaccines or meningococcal conjugate vaccine as a comparator.

Objective

To evaluate immune equivalence of SD and MD formulations of Vi-DT, and to assess the safety of both formulations compared with comparator vaccine.

Outcome Measurement

Blood draw for immunogenicity was performed at baseline prior to vaccine receipt and at four weeks after vaccination for a subset of participants to determine anti-Vi IgG geometric mean titers (GMT) and seroconversion rates. The primary outcome was comparison of anti Vi-IgG seroconversion and GMT between the two formulations of Vi-DT at 4 weeks following vaccine administration. Immune equivalence of MD and SD formulations was confirmed when the two-tailed 95% confidence interval (CI) of the GMT ratio is within [0.67, 1.5] at a two-sided significance level of 0.05. All participants were followed for safety events for six months after vaccine administration.

Randomization

Participants were randomized to receive SD Vi-DT, MD Vi-DT, or meningococcal conjugate vaccines in 2.5:2.5:1 allocation ratio.

Blinding

Study participants and observers were blinded to treatment assignment.

Findings

Immune equivalence of SD (n=252) and MD (n=247) formulations was confirmed by anti-Vi IgG GMT ratio of 1.14 (95%CI: 0.91, 1.43) with respective GMTs in the MD and SD groups of 640.62 IU/mL (95%CI: 546.39, 751.11) and 562.57 IU/mL (95%CI: 478.80, 661.00) (p=0.259). Similarly, anti-Vi IgG seroconversion rate difference between the two formulations of ‒0.43% (95%CI: -4.42, 3.56) confirmed immune equivalence with corresponding seroconversion rates of 98.38% (95%CI: 95.91, 99.37) and 98.81% (95%CI: 96.56, 99.59) in MD and SD Vi-DT formulations, respectively (p=0.722). Both formulations of Vi-DT had a satisfactory safety profile - all five serious adverse events reported during the study were unrelated to the investigational product.

Interpretation

The MD and SD formulations of Vi-DT elicited robust and equivalent immune responses following one dose vaccination, and both formulations demonstrated a favorable safety profile.

Trial Registration

ClinicalTrials.gov: NCT04204096.

Funding

This study was funded by the Bill & Melinda Gates Foundation (OPP 1115556).

Genomic epidemiology of Salmonella Typhi in Central Division, Fiji, 2012 to 2016

BACKGROUND

Typhoid fever is endemic in some Pacific Island Countries including Fiji and Samoa yet genomic surveillance is not routine in such settings. Previous studies suggested imports of the global H58 clade of Salmonella enterica var Typhi (Salmonella Typhi) contribute to disease in these countries which, given the MDR potential of H58, does not auger well for treatment. The objective of the study was to define the genomic epidemiology of Salmonella Typhi in Fiji.

METHODS

Genomic sequencing approaches were implemented to study the distribution of 255 Salmonella Typhi isolates from the Central Division of Fiji. We augmented epidemiological surveillance and Bayesian phylogenomic approaches with a multi-year typhoid case-control study to define geospatial patterns among typhoid cases.

FINDINGS

Genomic analyses showed Salmonella Typhi from Fiji resolved into 2 non-H58 genotypes with isolates from the two dominant ethnic groups, the Indigenous (iTaukei) and non-iTaukei genetically indistinguishable. Low rates of international importation of clones was observed and overall, there were very low levels an antibiotic resistance within the endemic Fijian typhoid genotypes. Genomic epidemiological investigations were able to identify previously unlinked case clusters. Bayesian phylodynamic analyses suggested that genomic variation within the larger endemic Salmonella Typhi genotype expanded at discreet times, then contracted.

INTERPRETATION

Cyclones and flooding drove 'waves' of typhoid outbreaks in Fiji which, through population aggregation, poor sanitation and water safety, and then mobility of the population, spread clones more widely. Minimal international importations of new typhoid clones suggest that targeted local intervention strategies may be useful in controlling endemic typhoid infection. These findings add to our understanding of typhoid transmission networks in an endemic island country with broad implications, particularly across Pacific Island Countries.

FUNDING

This work was supported by the Coalition Against Typhoid through the Bill and Melinda Gates Foundation [grant number OPP1017518], the Victorian Government, the National Health and Medical Research Council Australia, the Australian Research Council, and the Fiji Ministry of Health and Medical Services.

Prevention of typhoid by Vi conjugate vaccine and achievable improvements in household WASH: Evidence from a cluster-randomized trial in Dhaka, Bangladesh

BACKGROUND

Typhoid fever contributes to approximately 135,000 deaths annually. Achievable improvements in household water-hygiene-sanitation (WASH) combined with vaccination using typhoid conjugate vaccines (TCVs) may be an effective preventive strategy. However, little is known about how improved WASH and vaccination interact to lower the risk of typhoid.

METHODS

61,654 urban Bangladeshi children aged 9 months to <16 years, residing in 150 clusters with a baseline population of 205,760 residents, were randomized 1: 1 by cluster to Vi-tetanus toxoid TCV or Japanese Encephalitis (JE) vaccine. Surveillance for blood culture-confirmed typhoid fever was conducted over two years. Existing household WASH status was assessed at baseline as Better or Not Better using previously validated criteria. The reduction in typhoid risk among all residents associated with living in TCV clusters, Better WASH households, or both was evaluated using mixed-effects Poisson regression models.

RESULTS

The adjusted reduced risk of typhoid among all residents living in the clusters assigned to TCV was 55% (95% confidence interval (CI): 43%,65%; p < 0.001), and that of living in Better WASH households, regardless of cluster, was 37% (95%CI: 24%,48%; p < 0.001). The highest risk of typhoid was observed in persons living in households with Not Better WASH in the JE clusters. In comparison with these persons, those living in households with Better WASH in the TCV clusters had an adjusted reduced risk of 71% (95%CI: 59%, 80%; p < 0.001).

CONCLUSION

Implementation of TCV programs combined with achievable and culturally acceptable household WASH practices were independently associated with a significant reduction in typhoid risk.

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.

Paediatric enteric fever in Brussels: a case series over 16 years

Enteric fever (EF) is a major public health problem and a witness of the global health disparities. It is caused by Salmonella enterica serovar Typhi (Salmonella ser. Typhi) and Salmonella enterica serovar Paratyphi A, B, C (Salmonella ser. Paratyphi) and is estimated to infect 12-26 million persons yearly. Paediatric data on enteric fever in Europe are scarce. A case series of EF was analysed to describe the clinical presentation, laboratory characteristics and diagnostic challenges identified in a paediatric population in Brussels. We performed a retrospective study of all lab-confirmed cases of enteric fever in children aged 0-15 years at two Brussels teaching hospitals, between January 2005 and December 2020. We reviewed age, gender, travel history, consultations before diagnosis, hospitalisation duration, clinical symptoms and laboratory findings. There were 34 positive isolates of S. typhi and S. paratyphi: 31 patients had positive blood culture, 1 patient had positive bone aspirate and 2 patients had positive stool culture (one was excluded for missing data). There were 20 girls (60%). Median age was 3.5 years (range 5 months to 14 years). Travel to EF endemic areas was present in 55% of patients. Diagnosis was delayed in 80% of children. Eosinopenia was present in 93% of the cohort. The patients had not received any preventive travel education or vaccination.  Conlusion: Enteric fever poses diagnostic challenges to clinicians. Eosinopenia in a febrile patient coming from the tropics should raise suspicion of EF. Travellers to endemic areas should be better educated about EF risks, and typhoid fever vaccination must be promoted. What is Known: • Enteric fever is a global public health problem and includes typhoid and paratyphoid fever. • Typhoid fever is vaccine preventable disease. Paratyphoid fever is not vaccine preventable. What is New: • Enteric fever diagnosis is very challenging in non-endemic settings, and a large proportion of patients may develop serious complications if they receive delayed management. Occurrence of small family clusters is possible and mandates education and monitoring of the families of enteric fever affected children. • We report that the widest majority of our enteric fever affected patients (69%) had aneosinophilia (zero eosinophil count), and almost all patients (93%) had eosinopaenia (less than 50 eosinophil count) during their bacteriaemic phase.

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.

Sepsis and disseminated intravascular coagulation are rare complications of typhoid fever: A case report

INTRODUCTION

and importance: Typhoid fever is an infection caused by Salmonella typhi. The common complications are intestinal perforation and typhoid encephalopathy. Cases of typhoid fever with sepsis and/or disseminated intravascular coagulation (DIC) are rarely reported, even though typhoid fever is endemic in Indonesia.

CASE PRESENTATION

A 4-year-old male referral case from a district hospital was experiencing fever, decrease of consciousness and massive bleeding from his gastrointestinal tract and nose. Investigation revealed results from the IgM typhoid test using Tubex®TF, with the score of +8. PELOD 2 score was 10, and PSOFA was 5. DIC score was 7. Based on these findings, the patient was diagnosed with typhoid fever, with DIC and sepsis being the complication of the typhoid fever.

CLINICAL DISCUSSION

DIC is mostly a subclinical event, and severe bleeding complications found in typhoid fever are uncommon, although DIC scores which indicate an imbalance of coagulation and fibrinolysis are markedly elevated in patients with typhoid. DIC can be a part of multi-organ dysfunction due to sepsis syndrome. Acute infection can also result in systemic activation of coagulation.

CONCLUSION

Sepsis and DIC are rare complications of typhoid fever. Typhoid fever can be presented with profound bleeding manifestation other than gastrointestinal bleeding, since it is a common symptom of typhoid fever. Further research should be conducted to postulate association between typhoid fever and DIC.

Travel vaccines throughout history

Vaccinations are an important component of travel medicine. Beyond protection of travelers, vaccines are administered to prevent the importation of vaccine-preventable diseases at home and at destination. Proof of immunization to travel dates back to the first smallpox vaccine, developed by Edward Jenner in 1796. However, it took one century to generate the next vaccines against cholera, rabies, and typhoid fever. During the 20th century the armamentarium of vaccines used in travelers largely expanded with yellow fever, poliomyelitis, tetravalent meningococcal, and hepatitis A vaccines. The International Certificate of Inoculation and Vaccination was implemented in 1933. Currently there are vaccines administered to travelers following risk assessment, but also vaccines required according to the 2005 International Health Regulations and vaccines required at certain countries. Finally, within less than one year after the declaration of the coronavirus disease 2019 (COVID-19) pandemic, the first COVID-19 vaccines were launched and approved for emergency use to control the pandemic. Despite practical and ethical challenges, COVID-19 vaccine verifications have been widely used since spring 2021 in many activities, including international travel. In this article, we review the course of development of travel vaccines focusing on those for which a proof of vaccination has been or is required.

Prevalence and awareness of mode of transmission of typhoid fever in patients diagnosed with Salmonella typhi and paratyphi infections at the Saint Elisabeth General Hospital Shisong, Bui Division, Cameroon

Introduction

typhoid fever is a systemic infectious disease caused by the bacteria Salmonella enterica subspecies (typhi). It is a major cause of morbidity and mortality worldwide. This cross-sectional descriptive study aimed at determining the prevalence and awareness of the mode of transmission of Salmonella typhi among patients at the Saint Elisabeth General Hospital Shisong of Cameroon.

Methods

the study carried out from March 1^st, 2017 to May 31^st, 2017 recruited patients who presented at the hospital with clinical signs and symptoms of typhoid fever and who had lab requests for stool culture requested by the resident physician. The prevalence of Salmonella typhi infections among the patients and the proportion of patients with adequate knowledge on the mode of transmission of Salmonella typhi were estimated at a 95% CI. Data were analyzed using Epi info7.1.3.3.

Results

out of the 172 patients recruited for the studies, 52 (30.1%) were diagnosed with Salmonella typhi, 59.6% of which were male. Also, 3 (5.8%) were diagnosed with Salmonella paratyphoid A. A positive correlation between knowledge on the mode of transmission of Salmonella typhi and the level of education was established, showing that 92% of participants with a higher level of education indicating that typhoid fever can be contracted through consumption of contaminated water.

Conclusion

high prevalence of typhoid fever was observed in our study. The unawareness of the patients on typhoid fever and its contraction through contaminated water and food was positively correlated to the level of educations of the patients. These findings, therefore, suggest a public health challenge faced by inhabitants in this region where typhoid fever remains endemic. Scarcity of potable water, improper drainage systems, and problems of unsanitary toilets in Cameroon require urgent intervention.

Strategies for formulation of effervescent granules of an herbal product for the management of typhoid fever

Herbal medicines are currently being adopted as alternatives to orthodox medicines for the management of drug-resistant and emerging multidrug-resistant microbial strains of various diseases, including typhoid fever. A herbal decoction, MA 001, manufactured by the Centre for Plant Medicine Research (CPMR), has been used for the treatment of typhoid fever for at least two decades in Ghana with desirable outcomes. MA 001 is formulated from Citrus aurantifolia, Spondias mombin, Latana camara, Bidens pilosa, Trema occidentalis, Psidium guajava, Morinda lucida, Vernonia amygdalina, Persea americana, Paulina pinnatta, Momordia charantia and Cnestis ferruguinea medicinal plants. The low palatability and compliance to treatment due to the bulky nature of the decoction poses challenges in its optimum use. This study sought to design and formulate the therapeutic components of the aqueous herbal decoction of MA 001 into an optimal solid dosage form of effervescent granules to improve the delivery of MA 001 as well as increase patient compliance and convenience of product handling. The methods involved pre-formulation studies on the suitability of effervescent vehicles, formulation and evaluation of effervescent granules for drug excipient interactions using high performance liquid chromatography analysis. The findings indicate that the effervescent granules were suitable for use in the delivery of the therapeutic constituents for the treatment of typhoid fever as done with the decoction due to minimal herbal extract-excipient interaction.

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.

Circulation of third-generation cephalosporin resistant Salmonella Typhi in Mumbai, India

We report the persistent circulation of third-generation cephalosporin resistant Salmonella Typhi in Mumbai, linked to the acquisition and maintenance of a previously characterized IncX3 plasmid carrying the ESBL gene bla_SHV-12 and the fluoroquinolone resistance gene qnrB7 in the genetic context of a triple mutant also associated with fluoroquinolone resistance.

Salmonella Typhi stool shedding by enteric fever patients and asymptomatic chronic carriers in an endemic urban setting

The burden of Salmonella Typhi shedding in stool and its contribution to transmission in endemic settings is unknown. During passive surveillance S. Typhi shedding was seen during convalescence in 332 bacteremic typhoid patients although none persisted at one-year follow-up. Anti-Vi-IgG titres were measured in age-stratified cohort of serosurveillance participants. Systematic stool sampling of 303 participants with high anti-Vi-IgG titres identified one asymptomatic carrier shedding. These findings suggest ongoing S. Typhi transmission in this setting is more likely to occur from acute convalescent cases although better approaches are needed to identify true chronic carriers in the community to enable typhoid elimination.

Typhoid conjugate vaccine in Africa and Asia: Status of clinical evaluation and vaccine introduction

The disease burden of typhoid fever remains high in endemic areas in Asia and Africa, especially in children. Recent clinical trials conducted by the Typhoid Vaccine Acceleration Consortium show typhoid conjugate vaccine (TCV) to be safe, immunogenic, and efficacious at preventing blood culture-confirmed typhoid fever in African and Asian children. Pakistan, Liberia, and Zimbabwe recently introduced TCV through campaigns and routine childhood immunizations, providing protection for this vulnerable population. It is essential to continue this momentum while simultaneously filling data gaps - including typhoid complications - to inform decision-making on TCV introduction. A multidisciplinary approach including surveillance, water, sanitation, and hygiene investments, and large-scale TCV introduction is needed to decrease the burden and mortality of typhoid fever.

Five years of GenoTyphi: updates to the global Salmonella Typhi genotyping framework

In 2016, a whole-genome sequence (WGS)-based genotyping framework (GenoTyphi) was developed and provided a phylogenetically informative nomenclature for lineages of Salmonella Typhi, the etiological agent of typhoid fever. Subsequent surveillance studies have revealed additional epidemiologically important subpopulations, which require the definition of new genotypes and extension of associated software to facilitate the detection of antimicrobial resistance (AMR) mutations. Analysis of 4632 WGS provide an updated overview of the global S Typhi population structure and genotyping framework, revealing the widespread nature of haplotype 58 ([H58] 4.3.1) genotypes and the diverse range of genotypes carrying AMR mutations.

Prospects of future typhoid and paratyphoid vaccines in endemic countries

Low- and middle-income countries face a high burden of typhoid and paratyphoid fever due to poor water quality and inadequate sanitation. The World Health Organization (WHO) recommends the use of typhoid conjugate vaccines (TCV) in endemic settings and Gavi, the Vaccine Alliance, supports TCV introduction. There are currently two WHO-prequalified TCVs with Typbar TCV® introduced in Pakistan, Liberia, and Zimbabwe. Countries should assess disease burden and consider introduction of TCV for programmatic use. Several paratyphoid vaccine candidates are in early stages of development. An effective bivalent vaccine would be the most efficient way to control typhoid and paratyphoid fever.

A multi-centre, post-marketing surveillance study of Vi polysaccharide-tetanus toxoid conjugate vaccine (Typbar TCV®) in India

A typhoid Vi capsular-polysaccharide tetanus toxoid conjugate vaccine (Typbar-TCV®) was recommended by the World Health Organization for use in children >6 months of age. The present post-marketing surveillance study was intended to assess the clinical safety of approximately 11 million doses of TCV sold till 2019 in a diverse age range Indian population. Both active and passive post-marketing surveillance studies were conducted at multiple centers. Active surveillance was performed in two periods, Period-I: February to October 2016, Period-II: April 2017 to October 2018. In Period-II, the Brighton Collaboration Criteria adverse event case definitions were used. Passive surveillance was performed from February 2016 to December 2019 through voluntary reporting by pediatricians across India. During the active surveillance, 1147 adverse events were reported among 4,991 (23.0%) subjects in Period-I, and 596 adverse events among 3898 (21.3%) subjects in Period-II. The most frequent adverse events were fever (9.2% and 12.02%in Periods I and II, respectively), pain at the injection site (8.3% and 7.33%), and swelling (4.0% and 1.93%). No serious adverse events (SAEs) were reported during either Period. Passive surveillance revealed 235 adverse events, including 25 SAEs requiring hospitalization, of which two were due to typhoid fever. All the events mentioned above occurred within one week of vaccination, and all the subjects have recovered from AEs with medications. All reported adverse events resolved with no clinical sequelae. Observations in this study are consistent with the pre-licensure studies with no additional safety signals detected, confirming that Typbar-TCV® is safe.

Abbreviations: AE: Adverse event; LMIC: low- and middle-income countries; PMS: Post-marketing surveillance; SAE: Serious adverse event; TCV: Vi-polysaccharide tetanus –toxoid conjugate vaccine (Typbar-TCV®)

Genomic surveillance reveals international circulation and local transmission of Salmonella enterica serovars Typhi and Paratyphi A in Taiwan

BACKGROUND/PURPOSE

Morbidity and mortality from typhoid and paratyphoid fever remain an important problem for public health authorities in developing countries. In countries with lower incidences, most cases occur in travelers who visit regions in which typhoid and paratyphoid fever are highly endemic. The aim was to evaluate the source and transmission dynamics of typhoid and paratyphoid fever in Taiwan by using genomic analysis.

METHODS

During 2012-2019, 15 clinical isolates of Salmonella Typhi and S. Paratyphi A were collected. Demographic and clinical information of the infections were analyzed. We performed whole genome sequencing and evolutionary analysis on these isolates.

RESULTS

Clinical and microbiological data from 7 S. Typhi and 8 S. Paratyphi A isolates in Taiwan showed epidemiological and bacterial genomic link to the infection in South and Southeast Asia. The Taiwanese typhoidal isolates also share highly similar genomes with those collected from UK, indicating global circulation of the typhoidal clones. Local transmission of the imported but indigenized international clones was observed. Mutations occurring at gyrA 83 aa, including S83Y and S83F, were identified in the ciprofloxacin-resistant strains.

CONCLUSION

Due to the advance of global transportation and communication, the transmission mode of infectious disease has been modified. Domestic typhoid and paratyphoid fever caused by international resistant clones can occur in low-incidence countries. Genome analysis showed that the indigenous clone originally imported from other countries has been circulating in Taiwan for over a decade.

Surface-enhanced Raman spectroscopy for comparison of serum samples of typhoid and tuberculosis patients of different stages

BACKGROUND

Surface-enhanced Raman spectroscopy (SERS) is a reliable tool for the identification and differentiation of two different human pathological conditions sharing the same symptomology, typhoid and tuberculosis (TB).

OBJECTIVES

To explore the potential of surface-enhanced Raman spectroscopy for differentiation of two different diseases showing the same symptoms and analysis by principal component analysis (PCA) and partial least square discriminate analysis (PLS-DA).

METHODS

Serum samples of clinically diagnosed typhoid and tuberculosis infected individuals were analyzed and differentiated by SERS using silver nanoparticles (Ag NPs) as a SERS substrate. For this purpose, the collected serum samples were analyzed under the SERS instrument and unique SERS spectra of typhoid and tuberculosis were compared showing notable spectral differences in protein, lipid and carbohydrates features. Different stages of the diseased class of typhoid (Early acute and late acute stage) and tuberculosis (Pulmonary and extra-pulmonary stage) were compared with each other and with healthy human serum samples, which were significantly separated. Moreover, SERS data was analyzed using multivariate data analysis techniques including principal component analysis (PCA) and partial least square discriminate analysis (PLS-DA) and differences were so prominent to observe.

RESULTS

SERS Spectral data of typhoid and tuberculosis showed clear differences and were significantly separated using PCA. SERS spectral data of both stages of typhoid and tuberculosis were separated according to 1st principle component. Moreover, by analyzing data using partial least square discriminate analysis, differentiation of two disease classes were considered more valid with a 100% value of sensitivity, specificity and accuracy.

CONCLUSION

SERS can be employed for identification and comparison of two different human pathological conditions sharing same symptomology.

Safety and immunogenicity of Vi-typhoid conjugate vaccine co-administration with routine 9-month vaccination in Burkina Faso: A randomized controlled phase 2 trial

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This is the first study on the co-administration of typhoid conjugate vaccine (TCV) in West Africa.

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Co-administration of TCV with routine vaccines in a typhoid-endemic country was successful.

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TCV was safely co-administered at nine months with yellow fever and measles-rubella vaccines.

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Single-dose TCV was immunogenic in 9-month-old children.

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There was no safety signal related to TCV vaccination or co-administration.

Objectives

In 2017, the World Health Organisation (WHO) pre-qualified a single-dose typhoid conjugate vaccine (TCV) and identified TCV co-administration studies as a research priority. Accordingly, we tested co-administration of Typbar TCV® (Bharat Biotech International) with measles-rubella (MR) and yellow fever (YF) vaccines.

Methods

We conducted a randomized, double-blind, and controlled, phase 2 trial in Ouagadougou, Burkina Faso. Healthy children aged 9–11 months were randomized 1:1 to receive TCV (Group 1) or control vaccine (inactivated polio vaccine (IPV), Group 2). Vaccines were administered intramuscularly with routine MR and YF vaccines. Safety was assessed by (1) local and systemic reactions on days 0, 3, and 7; (2) unsolicited adverse events within 28 days; and (3) serious adverse events (SAEs) within six months after immunization.

Results

We enrolled, randomized, and vaccinated 100 eligible children (49 Group 1 and 51 Group 2). Safety outcomes occurred with similar frequency in both groups: local/solicited reactions (Group 1: 1/49, Group 2: 3/50), systemic/solicited reactions (Group 1: 4/49, Group 2: 9/50), unsolicited adverse events (Group 1: 26/49, Group 2: 33/51), and SAEs (Group 1: 2/49, Group 2: 3/51). TCV conferred robust immunogenicity without interference with MR or YF vaccines.

Conclusion

TCV can be safely co-administered with MR and YF vaccines to children at the 9-month vaccination visit.

Salmonella Typhi acquires diverse plasmids from other Enterobacteriaceae to develop cephalosporin resistance

Background

Recent reports have established the emergence and dissemination of extensively drug resistant (XDR) H58 Salmonella Typhi clone in Pakistan. In India where typhoid fever is endemic, only sporadic cases of ceftriaxone resistant S. Typhi are reported. This study aimed at elucidating the phylogenetic evolutionary framework of ceftriaxone resistant S. Typhi isolates from India to predict their potential dissemination.

Methods

Five ceftriaxone resistant S. Typhi isolates from three tertiary care hospitals in India were sequenced on an Ion Torrent Personal Genome Machine (PGM). A core genome single-nucleotide-polymorphism (SNP) based phylogeny of the isolates in comparison to the global collection of MDR and XDR S. Typhi isolates was built. Two of five isolates were additionally sequenced using Oxford Nanopore MinION to completely characterize the plasmid and understand its transmission dynamics within Enterobacteriaceae.

Results

Comparative genomic analysis and detailed plasmid characterization indicate that while in Pakistan (4.3.1 lineage I) the XDR trait is associated with bla_CTX-M-15 gene on IncY plasmid, in India (4.3.1 lineage II), the ceftriaxone resistance is due to short term persistence of resistance plasmids such as IncX3 (bla_SHV-12) or IncN (bla_TEM-1B + bla_DHA-1).

Conclusion

Considering the selection pressure exerted by the extensive use of ceftriaxone in India, there are potential risks for the occurrence of plasmid transmission events in the predominant H58 lineages. Therefore, continuous monitoring of S. Typhi lineages carrying plasmid-mediated cephalosporin resistant genes is vital not just for India but also globally.

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S. Typhi to develop cephalosporin resistance by acquiring diverse plasmids from other Enterobacteriaceae.

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Independent acquisition of drug-resistant plasmids such as IncX3 and IncN with genes encoding beta-lactamases in H58 lineage II of S. Typhi.

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A short-term persistence of drug-resistant plasmids in H58 lineage II can be the reason for the sporadic cases cephalosporin resistant S. Typhi in India.

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Plasmid acquisition and maintenance of cephalosporin resistant S. Typhi appears to be specific to the phylogenetic lineage.

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Critical strategies in monitoring and control of cephalosporin resistant S. Typhi is needed to tackle further public health crisis.

Surface-enhanced Raman spectroscopy analysis of serum samples of typhoid patients of different stages

BACKGROUND

Surface-enhanced Raman spectroscopy (SERS) of body fluids is considered a quick, simple and easy to use method for the diagnosis of disease.

OBJECTIVES

To evaluate rapid, reliable, and non-destructive SERS-based diagnostic tool with multivariate data analysis including principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) for classification of different stages of typhoid on the basis of characteristic SERS spectral features.

METHODS

SERS has been used for analysis of serum samples of different stages of typhoid including early acute stage and late acute stage in comparison with healthy samples, in order to investigate capability of this technique for diagnosis of typhoid. SERS spectral features associated with the biochemical changes taking place during the development of the typhoid fever were analyzed and identified.

RESULTS

The value of area under the receiver operating characteristics (AUROC) for early acute stage versus healthy is 0.87 and that for healthy versus late acute stage is 0.52. PLS-DA classifier model gives values of 100 % for accuracy, sensitivity and specificity, respectively for the SERS spectral data sets of healthy versus early acute stage. Moreover, this classifier model gives values of 91 %, 89 % and 97 % for accuracy, sensitivity and specificity, respectively for the SERS spectral data sets of healthy versus late acute stage.

CONCLUSIONS

Based on preliminary work it is concluded that SERS has potential to diagnose various stages of typhoid fever including early acute and late acute stage in comparison with healthy samples.

Post typhoid fever neuroretinitis with serous retinal detachment and choroidal involvement-A case report

Purpose

To report post typhoid fever neuroretinitis with Serous Retinal Detachment and choroidal involvement.

Observation

Patients with diminished vision post typhoid fever can present with neuroretinitis with serous retinal detachment.

Conclusion and importance

With help from noninvasive imaging such as optical coherence tomography angiography(OCTA) and Deep Range Imaging(DRI), we were able to conclude choroidal involvement – which has not been discussed in literatures yet.OCTA and choroidal thicknessboth served as agood indicators for monitoring the response of treatment in this case.

Extensively drug-resistant Salmonella Typhi in a patient returning from Pakistan, complicated by relapse with meropenem monotherapy

In developing countries, typhoid fever is a common cause of febrile illness accompanied by abdominal pain and weakness. It is caused by Salmonella enterica serovar Typhi. Humans are the only known reservoir of infection, and typhoid fever is common in regions where access to clean water and sanitation is limited. The antimicrobials of choice for a case of typhoid fever acquired outside Pakistan are third generation cephalosporins. Lately, cases of extensively drug-resistant (XDR) Salmonella Typhi have been reported in people with a travel history to Pakistan. We present a case of XDR typhoid fever which relapsed after treatment with meropenem.

[Etiological survey and traceability analysis of five cases of typhoid fever during the same period in Yantai city]

Objective: To analyze the etiological characteristics and molecular epidemiological correlation of five cases of typhoid fever during the same period in yantai city. Methods: Six S. Typhis strains were isolated from 5 typhoid patients and epidemiological samples in Yantai city in 2018. The onset time of the cases were from May 26, 2018 to July 24, 2018, distributed in Shuidao Town of Muping District, Dengzhou Street of Penglai District, Donglai Street of Longkou District, Wenhua Street of Muping District and Fulaishan Street of zhifu District. S. Typhis strains were analyzed by conventional bacterial isolation method and XbaⅠ/BlnⅠ double-enzyme digestion pulse-field gel electrophoresis (PFGE). Meanwhile, ViaB virulence gene detection and 27 common antibiotics sensitivity tests were conducted to study the etiology of S. Typhis. Results: Six strains of S. Typhi were isolated from 5 patients and the domestic egg of one patient, which were divided into 4 PFGE patterns by PFGE-XbaⅠ and PFGE-BlnⅠ and among which 3 strains had the same PFGE patterns.One multi-drug resistant strain (foreign patient), one single-drug resistant strain (patient with a history of provincial retention), and one completely sensitive strain were detected. The three strains of the same PFGE pattern exhibit the same drug-sensitive phenotype which were intermediate against aminoglycosides and quinolones and susceptibility against the other antibiotics.All of the strains carried the ViaB virulence factor except the strain from the foreign patient. Conclusion: Local S. Typhi is susceptibility or intermediate against antibiotics commonly used in clinic.Sporadic cases of typhoid fever and typhoid imported infections still need attention.

A rare case of septic arthritis of the knee caused by Salmonella typhi with preexisting typhoid fever in a healthy, immunocompetent child - A case report

Introduction

Septic arthritis is a rapid and progressive infection caused by invasion of bacteria into the synovial joint. Disease of the joint causedby Salmonella spp in healthy children is an unusual event, with an estimated incidence of 0.1 to 0.2% of septic arthritis cases among children. The incidence of knee septic arthritis caused by Salmonella typhi with preexisting typhoid fever is very rare.

Method

We reported a case of 2-years old boy with a history of saddle-type fever 2 weeks prior to right knee pain. Typhoid fever was confirmed by immunoassay test. Knee septic arthritis was established from clinical findings, increased CRP level, ultrasonography, and joint aspiration. Culture of the aspirate subsequently grew Salmonella typhi. This case report had been reported in line with SCARE criteria.

Result

Arthrotomy and debridement were immediately performed.Intravenous piperacillin tazobactam was given for 6 days and replaced by amoxicillin clavulanic acid after the culture and sensitivity test was available. Patient recovered completely 5 months post surgery and showed excellence result with normal range of knee joint motion.

Conclusion

This case report suggests that any episode of joint swelling following preexisting typhoid fever should arise the physician’s awareness toward the possibility of septic arthritis and warrant immediate as well as proper management.

Predictive evaluation of pediatric patients based on their typhoid fever status using linear discriminant model

Epidemiologic studies have established a relationship between pediatric patients and typhoid fever infection. This study was carried out to ascertain if specific hematological measurements of the pediatric patients discriminate between their positive and negative status to typhoid infection and to produce a rule for classifying other pediatric patients. Discriminant analysis was applied to predict the probability of a specific categorical outcome based on several explanatory variables (predictors). This study analyzed the differentiation between two hundred pediatric patients attending Landmark University Medical Centre based on their typhoid fever status. The hematological parameters considered were Packed Cell Volume, White Blood Cell count; Neutrophil, Erythrocyte level, Hemoglobin and Platelet count, Assay of samples were performed using standard procedures. Fisher's Linear Discriminant Method was used for classification of variables in this study. With the use of the Fisher's Linear Discrimination method for classification of the obtained data, a minimum value of -0.0067 was obtained implying that any new pediatric patient with a discriminant score above -0.0067 would be diagnosed to be typhoid negative; otherwise, they would be classified as typhoid positive pediatric patients. The efficiency of this method of classification was tested using two approaches; Retribution estimate approach and leaving-one out approach which showed a prevalence rate of typhoid positive patients at 75.8% and 74.7% respectively. This data analysis hypotheses that typhoid fever is highly endemic amongst our study subjects. A point-of-care diagnosis with a strong positive predictive value, which improves pediatric enteric fever diagnosis, is strongly advocated.

The burden of typhoid fever in Klang Valley, Malaysia, 2011-2015

BACKGROUND

Typhoid fever causes global morbidity and mortality and is a significant health burden, particularly in low- and middle-income countries. The direct fecal-oral route is the main transmission mode, but indirect environmental transmission could occur, particularly in urban settings. This study aimed to investigate the burden and trend of typhoid fever, reporting the coverage system between government and private practice and pattern of multidrug-resistant (MDR) typhoid cases in the urban Klang Valley area from 2011 to 2015.

METHODS

The data from a cross-sectional study retrieved from the e-Notifikasi System, a national reporting system for communicable diseases provided by the Disease Control Division, Ministry of Health Malaysia and secondary data of all the typhoid cases were obtained from the public and private hospitals and laboratories in Klang Valley. Descriptive analysis was performed to examine the sociodemographic characteristics, spatial mapping was conducted to examine trends, and the crude incidence rates of confirmed typhoid cases and percentage of reporting coverage were calculated. Significant differences between MDR and non-MDR Salmonella typhi were determined in the patient's sociodemographic characteristics, which were analyzed using χ2 test. P values < 0.05 were considered statistically significant.

RESULTS

In total, 507 typhoid fever cases were reported in Klang Valley; however, only 265 cases were confirmed by culture tests. The crude incidence rates of confirmed cases were between 0.5 to 0.7 but peaked at 1.42 per 100,000 population in 2015. Most typhoid fever cases were observed among men (55.6%), individuals aged 21 to 30 years (27.6%), Malaysians (86.3%) and individuals of Malay ethnicity (52.1%). The reporting coverage of confirmed cases was 78.9% and non-reporting coverage of unconfirmed typhoid cases was 79.5%. The predictive value positive (PVP) was 89.3, and 7.5% were detected as MDR Salmonella typhi. Statistical significance was found in gender, citizenship and ethnicity regarding MDR Salmonella typhi (p = 0.004, p = 0.008 and p = 0.034, respectively).

CONCLUSIONS

The local transmission of typhoid is still prevalent in the Klang Valley despite rapid urbanization and development in recent years. These findings are essential for policy makers to plan and implement focused and effective preventative activities to curb typhoid infection in urban areas.

Complications and mortality of typhoid fever: A global systematic review and meta-analysis

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Complications and death are considerable among hospitalized patients with typhoid fever.

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Case fatality ratio of typhoid fever was higher in Africa compared to Asia.

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Among studies in Africa, 20% of patients with typhoid intestinal perforation died.

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Delays in care were correlated with increased typhoid case fatality ratio in Asia.

Objectives

Updated estimates of the prevalence of complications and case fatality ratio (CFR) among typhoid fever patients are needed to understand disease burden.

Methods

Articles published in PubMed and Web of Science from 1 January 1980 through 29 January 2020 were systematically reviewed for hospital or community-based non-surgical studies that used cultures of normally sterile sites, and hospital surgical studies of typhoid intestinal perforation (TIP) with intra- or post-operative findings suggestive of typhoid. Prevalence of 21 pre-selected recognized complications of typhoid fever, crude and median (interquartile range) CFR, and pooled CFR estimates using a random effects meta-analysis were calculated.

Results

Of 113 study sites, 106 (93.8%) were located in Asia and Africa, and 84 (74.3%) were non-surgical. Among non-surgical studies, 70 (83.3%) were hospital-based. Of 10,355 confirmed typhoid patients, 2,719 (26.3%) had complications. The pooled CFR estimate among non-surgical patients was 0.9% for the Asia region and 5.4% for the Africa region. Delay in care was significantly correlated with increased CFR in Asia (r = 0.84; p<0.01). Among surgical studies, the median CFR of TIP was 15.5% (6.7–24.1%) per study.

Conclusions

Our findings identify considerable typhoid-associated illness and death that could be averted with prevention measures, including typhoid conjugate vaccine introduction.

In vitro and in vivo anti-salmonella properties of hydroethanolic extract of Detarium microcarpum Guill. & Perr. (Leguminosae) root bark and LC-MS-based phytochemical analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Typhoid fever treatment remains a challenge in endemic countries. Detarium microcarpum is traditionally used to manage typhoid.

AIM OF THE STUDY

The study aims to explore the efficacy of hydroethanolic extract of Detarium microcarpum root bark in rats infected with salmonella.

MATERIAL AND METHODS

The phytochemical profile of the extract was obtained by UHPLC-MS analysis in an attempt of standardization. The in vitro antimicrobial activity was determined using broth dilution method. Salmonella infection was induced by oral administration of S. thyphimurium to immunosuppressed rats. Infected rats were then treated 2 h later with the extract (75, 150 and 300 mg/kg), distilled water (normal and salmonella control) and ciprofloxacin (8 mg/kg) for control. Body weight was monitored and stools were cultured to determine the number of colony-forming units. At the end of treatment, animals were sacrificed, blood and organs were collected for hematological, biochemical and histopathological analyses.

RESULTS

Detarium microcarpum extract as well as the isolated compound (rhinocerotinoic acid) exhibited good antimicrobial activity in vitro with bacteriostatic effects. The plant extract significantly (p < 0.05) inhibited the bacterial development in infected animals with an effective dose (ED₅₀) of 75 mg/kg. In addition, the extract prevented body weight loss, hematological, biochemical and histopathological damages in treated rats.

CONCLUSION

Detarium microcarpum extract possesses antisalmonella properties justifying its traditional use for the typhoid fever management.

Salmonella Typhi and Paratyphi A infections in Cambodian children, 2012-2016

OBJECTIVES

Enteric fever remains an important diagnostic and treatment challenge in febrile children living in the tropics. In the context of a national Salmonella enterica serovar Paratyphi A outbreak, the objective of this retrospective study was to compare features of S. Typhi and S. Paratyphi A infections in Cambodian children.

METHODS

Clinical and laboratory features were reviewed for 192 blood culture-confirmed children with S. Typhi and S. Paratyphi A infections presenting to a paediatric referral hospital in Siem Reap, 2012-2016.

RESULTS

Children with S. Typhi infections were younger, were more likely to have chills and/or diarrhoea, and were more frequently hospitalized than those with S. Paratyphi A infections. Over three quarters (88.3%) of S. Typhi isolates were multidrug-resistant, compared to none of the S. Paratyphi A.

CONCLUSIONS

In this small study of Cambodian children, S. Typhi infections were more severe than S. Paratyphi A infections. Antibiotic resistance limits treatment options for enteric fever in this population.

Changes in some haematological parameters in typhoid fever patients attending Landmark University Medical Center, Omuaran-Nigeria

Background

Typhoid or enteric fever is caused by Salmonella typhi. It is largely a disease of developing nations due to poor standard of hygiene and unavailability of potable water. The most prominent feature of the infection is fever which gradually rises to a high plateau. The prevalence of typhoid fever has been on the increase which is associated with several hematological parameters.

Objectives

This study was carried out to determine the changes in various hematological parameters in our study subjects.

Method

Four Hundred- (400) samples were obtained from volunteer subjects visiting the outpatient department of the Landmark University Medical Center. 200 typhoid positive samples were collected from subjects while 200 typhoid negative blood samples served as controls (From both male and female subjects each). Widal test was carried out as a confirmatory test for typhoid fever and evaluation of the hematological parameters were performed. The hematological parameters considered includes Packed Cell Volume (PCV), White Blood Cell count (WBC), Platelet count (PLT), Lymphocyte (LYMP) their implications on both male and female typhoid fever patients were also determined.

Results

The result showed a significant reduction in the values for PCV, WBC, ESR and HAE concentration in typhoid positive males in comparison to typhoid negative males. In females, a significant decrease was observed in values for PCV, ESR, HAE concentration and PLT in typhoid positive females when compared to typhoid negative females. These parameters when compared showed a significant decrease recorded in PCV, ESR and HAE concentration of the typhoid positive male patients in comparison to typhoid positive female patients.

Conclusion

This study implies that anemia, bone marrow suppression and hemaphagocytosis are likely resulting factors of typhoid fever due to the changes in the hematological parameters. Therefore, these parameters have to be further studied to allow for efficient management of this illness.

Designing a typhoid environmental surveillance study: A simulation model for optimum sampling site allocation

Environmental surveillance can be used for monitoring enteric disease in a population by detecting pathogens, shed by infected people, in sewage. Detection of pathogens depends on many factors: infection rates and shedding in the population, pathogen fate in the sewerage network, and also sampling sites, sample size, and assay sensitivity. This complexity makes the design of sampling strategies challenging, which creates a need for mathematical modeling to guide decision making.

In the present study, a model was developed to simulate pathogen shedding, pathogen transport and fate in the sewerage network, sewage sampling, and detection of the pathogen. The simulation study used Salmonella enterica serovar Typhi (S. Typhi) as the target pathogen and two wards in Kolkata, India as the study area. Five different sampling strategies were evaluated for their sensitivity of detecting S. Typhi, by sampling unit: sewage pumping station, shared toilet, adjacent multiple shared toilets (primary sampling unit), pumping station + shared toilets, pumping station + primary sampling units. Sampling strategies were studied in eight scenarios with different geographic clustering of risk, pathogen loss (decay, leakage), and sensitivity of detection assays. A novel adaptive sampling site allocation method was designed, that updates the locations of sampling sites based on their performance. We then demonstrated how the simulation model can be used to predict the performance of environmental surveillance and how it is improved by optimizing the allocation of sampling sites.

The results are summarized as a decision tree to guide the sampling strategy based on disease incidence, geographic distribution of risk, pathogen loss, and the sensitivity of the detection assay. The adaptive sampling site allocation method consistently outperformed alternatives with fixed site locations in most scenarios. In some cases, the optimum allocation method increased the median sensitivity from 45% to 90% within 20 updates.

A decision support system for multi-target disease diagnosis: A bioinformatics approach

Malaria and typhoid fever are revered for their ability to individually or jointly cause high mortality rate. Both malaria and typhoid fever have similar symptoms and are famous for their co-existence in the human body, hence, causes problem of under-diagnosis when doctors tries to determine the exact disease out of the two diseases. This paper proposes a Bioinformatics Based Decision Support System (BBDSS) for malaria, typhoid and malaria typhoid diagnosis. The system is a hybrid of expert system and global alignment with constant penalty. The architecture of the proposed system takes input diagnosis sequence and benchmark diagnosis sequences through the browser, store these diagnosis sequences in the Knowledge base and set up the IF-THEN rules guiding the diagnosis decisions for malaria, typhoid and malaria typhoid respectively. The matching engine component of the system receives as input the input sequence and applies global alignment technique with constant penalty for the matching between the input sequence and the three benchmark sequences in turns. The global alignment technique with constant penalty applies its pre-defined process to generate optimal alignment and determine the disease condition of the patient through alignment scores comparison for the three benchmark diagnosis sequences. In order to evaluate the proposed system, ANOVA was used to compare the means of the three independent groups (malaria, typhoid and malaria typhoid) to determine whether there is statistical evidence that the associated values on the diagnosis variables means are significantly different. The ANOVA results indicated that the mean of the values on diagnosis variables is significantly different for at least one of the disease status groups. Similarly, multiple comparisons tests was further used to explicitly identify which means were different from one another. The multiple comparisons results showed that there is a statistically significant difference in the values on the diagnosis variables to diagnose the disease conditions between the groups of malaria and malaria typhoid. Conversely, there were no differences between the groups of malaria and typhoid fever as well as between the groups of typhoid fever and malaria typhoid. In order to show mean difference in the diagnosis scores between the orthodox and the proposed diagnosis system, t-test statistics was used. The results of the t-test statistics indicates that the mean values of diagnosis from the orthodox system differ from those of the proposed system. Finally, the evaluation of the proposed diagnosis system is most efficient at providing diagnosis for malaria and malaria typhoid at 97% accuracy.

The first imported case of extensively drug-resistant Salmonella enterica serotype Typhi infection in Taiwan and the antimicrobial therapy

The first imported case of XDR typhoid fever in Taiwan contracted with a bacterial strain, which was most closely related to the bla_CTX-M-15-carrying strains linked to Pakistan. Meropenem, in combination with an antimicrobial with intracellular activity against Salmonella, should be used for the treatment of XDR typhoid fever.

[Laboratory testing and tracing analysis of a typhoid epidemic in Jiangyin city, Jiangsu Province]

To conduct outbreak identification and transmission factor analysis of typhoid epidemic occurred in Xinqiao town, Jiangyin city from June to September 2016. A total of 14 strains of Salmonella typhi isolated from confirmed cases were collected, and 65 external environment samples and 13 food samples related to the outbreak were taken. Real-time PCR was used to detect specific gene of Salmonella typhi in the samples. Conventional method was used to isolate strains. The strains isolated from both the samples and patients in the epidemic were subjected to antimicrobial susceptibility testing and PFGE molecular characteristics. Salmonella typhi strain was isolated from one external sample (well water of a deli processing plant). The results of drug susceptibility showed that 15 strains were resistant to nalidixic acid. A total of 15 strains of Salmonella typhi were divided into 2 molecular patterns by pulsed field gel electrophoresis. The fingerprints of PFGE from the 13 patients and the environmental isolate were completely consistent, and there was one band difference from the other patient isolate. Combined with the epidemiological investigation and laboratory test results, it was determined that the outbreak was caused by genetic clone of the same Salmonella typhi. Food processing plant should be one of the key links.

[Epidemiology profil of fever typhoid in Meknes (Morocco) 2013-2016]

INTRODUCTION

Twenty million cases of typhoid and paratyphoid fever (TF) are observed annually worldwide with more than 200,000deaths. These fevers occur in areas where hygiene is precarious, mainly in developing countries. The objective of this study was to describe epidemiological patterns of TF in Meknes, Morocco in order to improve preventive measures.

METHODS

We conducted a case series study based on data from 2013 to 2016 in the Meknes TF surveillance system. Data collected included socio-demographic variables, place of residence, season, mode of water supply, and food consumed. Diagnosis of TF was confirmed with the Widal test. Data were analyzed with Epi-info version 7 and mapping was done with Qgis version 2.18.1.

RESULTS

Three hundred and twenty-two cases were reported with a male/female sex ratio of 0.9. Average age was 26±20years. Incidence increased from 13 per 100.000inhabitants in 2013 to 8 per 100.000 inhabitants in 2016. Two hundred and seventy-nine (87%) cases occurred in urban areas and 174 (54%) cases developed in summer. One death was recorded.

CONCLUSION

Public awareness campaigns on health education for hygiene are needed. Focus should be placed on transmission by food handlers.