Case fatality rate and length of hospital stay among patients with typhoid intestinal perforation in developing countries: a systematic literature review

Defunctioning ileostomy for typhoid ileal perforations: Out of the frying pan into the fire?

Typhoid ileal perforation (TIP) is a common surgical emergency in low-middle income countries (LMICs). Its high surgical morbidity and mortality is due to its often late presentation or diagnosis, the patient's malnutrition, severe peritoneal contamination and unavailability of intensive care in most peripheral hospitals. This prompted the philosophy of minimizing the crisis by avoiding any repair or anastomosis, limiting the surgery in these physiologically compromised patients and performing only a temporary defunctioning ileostomy (DI) which could then be closed 10-12 weeks later.

Typhoid intestinal perforation in Francophone Africa, a scoping review

Typhoid intestinal perforation (TIP) is a leading cause of peritonitis and indication for emergency surgery in Africa, with reported mortality rates up to 30% in pediatric patients. Currently, data on TIP in Western databases are primarily from countries that speak English, likely due to non-English publication and citation biases. Despite the high burden of infectious diseases in Francophone Africa, data from these countries regarding TIP remain limited. This study aims to highlight the incidence and morbidity of TIP in Francophone African countries using an extended search algorithm. We conducted a scoping review using the PubMed, EMBASE, and SCOPUS databases with the keywords "peritonitis", "non-traumatic ileal perforation", and "typhoid" in Francophone African countries. Additionally, we contacted surgeons in Africa and concurrently used citation chasing to obtain data not found in western databases. In total, 32 studies from 12 countries were identified and included in this review. A total of 22 publications were in French. Patient median age was 20 years and TIP caused a median of 35% of acute peritonitis cases. Mortality rates ranged from 6-37% (median: 16%). Rate of complications ranged from 15-92% (median: 46%). Ileostomy creation as a treatment for TIP varied between hospitals (0-79%), with the highest rates reported in Niger. In Francophone Africa, TIP is associated with high morbidity and mortality, most commonly in children and young adults. Interventions, including improved sanitation and the introduction of typhoid conjugate vaccines into routine vaccination programs, have the potential to significantly decrease typhoid fever and its complications.

Asymptomatic Salmonella Myocarditis: A Case Report of a Rare Entity

Enteric fever typically displays symptoms like high fever, abdominal pain, constipation, and headaches, primarily affecting the digestive system. While it is commonly seen as a gastrointestinal infection, it can also lead to rare but significant cardiovascular issues. There have been only a few reported cases of enteric fever causing heart manifestations. We present a case of a young male with enteric fever-induced myocarditis, which, due to its rarity, can be challenging to diagnose and is essentially a diagnosis of exclusion. Cardiac MRI (CMR) is crucial for diagnosis, supported by ECG, echocardiograms, and troponin levels. The treatment involves standard approaches for cardiomyopathy, including angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, and diuretics. However, our patient presented as a case of asymptomatic myocarditis and fully recovered with treatment without any long-lasting heart problems. Our study aims to contribute to the limited body of knowledge on heart-related complications of enteric fever, raising awareness among clinicians of such presentations in enteric fever cases.

Typhoid fever

Typhoid fever is an invasive bacterial disease associated with bloodstream infection that causes a high burden of disease in Africa and Asia. Typhoid primarily affects individuals ranging from infants through to young adults. The causative organism, Salmonella enterica subsp. enterica serovar Typhi is transmitted via the faecal-oral route, crossing the intestinal epithelium and disseminating to systemic and intracellular sites, causing an undifferentiated febrile illness. Blood culture remains the practical reference standard for diagnosis of typhoid fever, where culture testing is available, but novel diagnostic modalities are an important priority under investigation. Since 2017, remarkable progress has been made in defining the global burden of both typhoid fever and antimicrobial resistance; in understanding disease pathogenesis and immunological protection through the use of controlled human infection; and in advancing effective vaccination programmes through strategic multipartner collaboration and targeted clinical trials in multiple high-incidence priority settings. This Primer thus offers a timely update of progress and perspective on future priorities for the global scientific community.

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 .

Use of onsite typhoid IgG/IgM combo test as rapid diagnostic test for typhoid fever

Background

The incidence of typhoid fever is increasing in Egypt. The Widal test is the evaluation most widely used in Egypt for diagnosis, but it has many drawbacks; therefore, new diagnostic tools are needed. Our aim was to evaluate the diagnostic accuracy of the onsite typhoid IgG/IgM combo rapid test in diagnosing typhoid fever.

Method

Blood specimens were collected from 90 patients (of all ages) who presented with fever of more than 4 days’ duration. The OnSite Combo test and the Widal test were performed for all patients.

Results

The OnSite Combo test results were positive in approximately 24% of all patients; the Widal test results were positive in 18.9%; and typhoid was diagnosed through blood culture in 32.2%. The OnSite Combo test had 72.4% sensitivity, 98.4% specificity, a positive predictive value of 95.5%, and a negative predictive value of 88.2%. In contrast, the Widal test had 51.7% sensitivity, 69.7% specificity, a positive predictive value of 88.2%, and a negative predictive value of 80.8%.

Conclusions

The onsite combo test was more efficacious than the Widal test in diagnosing typhoid fever.

Mimics of Crohn's Disease

Crohn's disease is a chronic inflammatory disease that can affect any portion of the gastrointestinal tract. Associated symptoms can vary based on the severity of disease, extent of involvement, presence of extraintestinal manifestations, and development of complications. Diagnosis is based on a constellation of findings. Many diseases can mimic Crohn's disease and lead to diagnostic conundrums. These include entities associated with the gastrointestinal luminal tract, vascular disease, autoimmune processes, various infections, malignancies and complications, drug- or treatment-induced conditions, and genetic diseases. Careful consideration of possible causes is necessary to establish the correct diagnosis.

The Burden of Typhoid Fever in Sub-Saharan Africa: A Perspective

While typhoid fever has largely been eliminated in high-income regions which have developed modern water, sanitation, and hygiene facilities, it remains a significant public health burden resulting in morbidity and mortality among millions of individuals in resource-constrained settings. Prevention and control efforts are needed that integrate several high-impact interventions targeting facilities and infrastructure, including those addressing improvements in sanitation, access to safe water, and planned urbanization, together with parallel efforts directed at effective strategies for use of typhoid conjugate vaccines (TCV). The use of TCVs is a critical tool with the potential of having a rapid impact on typhoid fever disease burden; their introduction will also serve as an important strategy to combat evolving antimicrobial resistance to currently available typhoid fever treatments. Well-designed epidemiological surveillance studies play a critical role in establishing the need for, and monitoring the impact of, typhoid fever control and prevention strategies implemented by public health authorities. Here, we present a perspective based on a narrative review of the impact of typhoid fever on morbidity and mortality in sub-Saharan Africa and discuss ongoing surveillance activities and the role of vaccination in prevention and control efforts.

Diagnostic bias during the COVID-19. A rare case report of salmonella typhi

Introduction

In poor countries, due to the limited resources, mostly they prescribe medications without proper diagnosis. The aim of this report is to show diagnostic bias of COVID-19 case.

Case presentation

A 17-year-old male patient was presented to the Hospital with a fever up to 39 °C associated with rigor, sweating, generalized body pain, myalgia, fatigue, loss of appetite, headache, and multiple joint pain with no swelling and redness. The vital signs were steady on physical examination, except temperature which was 39 °C. The chest was clear, and the pulse rate was 90 beats per minute. The heart rate relative bradycardia and lungs were normal. Both a PCR test for COVID-19, and a viral assay ELISA were negative. After further investigations, the culture findings revealed the strong development of Gram-negative coccobacilli (Salmonella serotype Typhi) bacteria under the microscope, which was confirmed by using VITEK 2 to identify it. and treated with ciprofloxacin tab, two times per day for five days and amikacin ampule 500 mg IV every 24 hours for 10 days.

Discussion

Fever is a well-known sign of COVID-19 infection which has been observed in 83%–98% of patients with COVID19. As a result, it may be difficult to tell the difference between COVID-19 and other febrile infections, causing delays in diagnosis and treatment and may blind the physician from considering other febrile illnesses.

Conclusion

Physicians should construct more comprehensive differential diagnoses for people who experience fever, headache, or myalgia symptoms that are linked to a pandemic. COVID-19.

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Differential diagnosis of patients with persistent Covid-19 sign should be considered.

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lack awareness of typhoid fever can lead to diagnostic bias during the COVID-19.

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Direct medical history and exposure can help clinicians to investigate of illnesses.

Clinicoepidemiological Observations of Enteric Fever in Infants: Experiences From a Tertiary Care Pediatric Hospital in North India

Background

There is a lack of evident data to explain the true scenario of age-specific enteric fever in India. The current study aimed to evaluate the burden and disease pattern of enteric fever among infants in a tertiary care pediatric hospital.

Methods

A prospective laboratory-based surveillance was conducted from April 2018 to January 2020 at a children’s hospital in North India, under the Surveillance for Enteric Fever in India study. The study included children <1 year of age in whom Salmonella serovar Typhi/Salmonella serovar Paratyphi grew in cultures from blood or sterile body fluid. The key outcome measures included disease spectrum and clinical presentation.

Results

Of the 10 737 blood cultures from infants, 26 were positive for S. Typhi or S. Paratyphi. The majority of cases occurred in infants aged 6–12 months, with the youngest being 1 month old. Fever with abdominal pain and diarrhea were the common symptoms, with 46% of infants requiring inpatient care. All of the isolates were susceptible to ceftriaxone. Third-generation cephalosporins were used as the first-line therapy for hospitalized infants. The average duration of fever was 8.6 days. The overall case-fatality rate among infants with enteric fever was 7.4%.

Conclusions

Enteric fever is a major contributor to disease and death among children. Robust surveillance studies are required to understand the true disease burden.

Ileal Perforation and Enteric Fever: Implications for Burden of Disease Estimation

Background

Ileal perforation occurs in about 1% of enteric fevers as a complication, with a case fatality risk (CFR) of 20%–30% in the early 1990s that decreased to 15.4% in 2011 in South East Asia. We report nontraumatic ileal perforations and its associated CFR from a 2-year prospective enteric fever surveillance across India.

Methods

The Surveillance for Enteric Fever in India (SEFI) project established a multitiered surveillance system for enteric fever between December 2017 and March 2020. Nontraumatic ileal perforations were surveilled at 8 tertiary care and 6 secondary care hospitals and classified according to etiology.

Results

Of the 158 nontraumatic ileal perforation cases identified,126 were consented and enrolled. Enteric fever (34.7%), tuberculosis (19.0%), malignancy (5.8%), and perforation of Meckel diverticulum (4.9%) were the common etiology. In those with enteric fever ileal perforation, the CFR was 7.1%.

Conclusions

Enteric fever remains the most common cause of nontraumatic ileal perforation in India, followed by tuberculosis. Better modalities of establishing etiology are required to classify the illness, and frame management guidelines and preventive measures. CFR data are critical for comprehensive disease burden estimation and policymaking.

Intestinal Perforations Associated With a High Mortality and Frequent Complications During an Epidemic of Multidrug-resistant Typhoid Fever in Blantyre, Malawi

Background

Typhoid fever remains a major source of morbidity and mortality in low-income settings. Its most feared complication is intestinal perforation. However, due to the paucity of diagnostic facilities in typhoid-endemic settings, including microbiology, histopathology, and radiology, the etiology of intestinal perforation is frequently assumed but rarely confirmed. This poses a challenge for accurately estimating burden of disease.

Methods

We recruited a prospective cohort of patients with confirmed intestinal perforation in 2016 and performed enhanced microbiological investigations (blood and tissue culture, plus tissue polymerase chain reaction [PCR] for Salmonella Typhi). In addition, we used a Poisson generalized linear model to estimate excess perforations attributed to the typhoid epidemic, using temporal trends in S. Typhi bloodstream infection and perforated abdominal viscus at Queen Elizabeth Central Hospital from 2008–2017.

Results

We recruited 23 patients with intraoperative findings consistent with intestinal perforation. 50% (11/22) of patients recruited were culture or PCR positive for S. Typhi. Case fatality rate from typhoid-associated intestinal perforation was substantial at 18% (2/11). Our statistical model estimates that culture-confirmed cases of typhoid fever lead to an excess of 0.046 perforations per clinical typhoid fever case (95% CI, .03–.06). We therefore estimate that typhoid fever accounts for 43% of all bowel perforation during the period of enhanced surveillance.

Conclusions

The morbidity and mortality associated with typhoid abdominal perforations are high. By placing clinical outcome data from a cohort in the context of longitudinal surgical registers and bacteremia data, we describe a valuable approach to adjusting estimates of the burden of typhoid fever.

Burden of Ileal Perforations Among Surgical Patients Admitted in Tertiary Care Hospitals of Three Asian countries: Surveillance of Enteric Fever in Asia Project (SEAP), September 2016-September 2019

Background

Typhoid fever is caused by Salmonella enterica subspecies enterica serovar Typhi (S. Typhi) and can lead to systemic illness and complications. We aimed to characterize typhoid-related ileal perforation in the context of the population-based Surveillance of Enteric Fever in Asia Project (SEAP) in Bangladesh, Nepal and Pakistan.

Methods

Between September 2016 and September 2019, all cases of nontraumatic ileal perforation with a clinical diagnosis of typhoid were enrolled from 4 tertiary care hospitals in Karachi, 2 pediatric hospitals in Bangladesh, and 2 hospitals in Nepal. Sociodemographic data were collected from patients or their caregivers, and clinical and outcome data were retrieved from medical records. Tissue samples were collected for histopathology and blood cultures where available.

Results

Of the 249 enrolled cases, 2 from Bangladesh, 5 from Nepal and 242 from Pakistan. In Pakistan, most of the cases were in the 0–15 (117/242; 48%) and 16–30 (89/242; 37%) age groups. In all countries, males were most affected: Pakistan 74.9% (180/242), Nepal 80% (4/5), and Bangladesh 100% (2/2). Blood culture was done on 76 cases; 8 (11%) were positive for S. Typhi, and all were extensively drug resistant (XDR) S. Typhi. Tissue cultures was done on 86 patients; 3 (3%) were positive for S. Typhi, and all were XDR S. Typhi, out of 86 samples tested for histopathology 4 (5%) revealed ileal perforation with necrosis. Culture or histopathology confirmed total 15 (11%) enteric fever cases with ileal perforation are similar to the clinically diagnosed cases. There were 16/242 (7%) deaths from Pakistan. Cases of ileal perforation who survived were more likely to have sought care before visiting the sentinel hospital (P = .009), visited any hospital for treatment (P = .013) compared to those who survived.

Conclusions

Although surveillance differed substantially by country, one reason for the higher number of ileal perforation cases in Pakistan could be the circulation of XDR strain of S. Typhi in Karachi.

Gastrointestinal and Hepatobiliary Complications of Extensively Drug-Resistant Typhoid at a Tertiary Care Hospital in Pakistan

INTRODUCTION

Typhoid fever is a major health problem in developing countries. Extensively drug-resistant (XDR) typhoid is an emerging threat to world health. The objectives of this study were to report our blood culture proven patients having XDR typhoid and compare the rate of gastrointestinal (GI) and hepatobiliary manifestations and complications of antimicrobial sensitive and resistant strains.

MATERIALS AND METHODS

This prospective observational study was carried out at a tertiary care hospital in Pakistan, from January 2019 till August 2020 on all consecutive blood culture proven patients of Salmonella typhi. A total of 57 cases of Salmonella were identified, of which 10 were nonresistant, seven multi drug-resistant (MDR), 39 extensively drug-resistant (XDR), and one was extended-spectrum beta lactamase (ESBL) positive. Alarmingly, one of the S. typhi isolate in addition to the first line drugs, was also resistant to azithromycin. Patients were treated with antibiotics according to antimicrobial susceptibility of the Salmonella in accordance with the World Health Organization (WHO) and Medical Microbiology and Infectious Diseases Society of Pakistan (MMIDSP) guidelines and GI and hepatobiliary complications were recorded.

RESULTS

Overall rate of complications was low. Some 10% (1/10) with nonresistant typhoid, 14% (1/7) with MDR, and 15% (6/39) of our patients with XDR typhoid fever had abdominal tenderness (p=0.95). None of the patients had GI bleeding, abdominal abscess, or peritonitis. Some 20% (2/10) patients with nonresistant typhoid, 29% (2/7) with MDR, and 18% (7/39) with XDR typhoid developed acute hepatitis, with greater than three times elevation of liver transaminases. There was no statistically significant difference in the occurrence of hepatitis between these groups (p=0.98). Interestingly, one of our patients with XDR typhoid also developed cholestatic hepatitis.

CONCLUSION

There is no significant difference in GI and hepatobiliary complications amongst antimicrobial sensitive and resistant strains of typhoid. However, emergence of resistant strains calls for focus on prevention and judicious use of antimicrobials.

A Multicenter Cost-of-Illness and Long-term Socioeconomic Follow-up Study in the Severe Typhoid Fever in Africa Program: Study Protocol

Background

There are limited data on typhoid fever cost of illness (COI) and economic impact from Africa. Health economic data are essential for measuring the cost-effectiveness of vaccination or other disease control interventions. Here, we describe the protocol and methods for conducting the health economic studies under the Severe Typhoid Fever in Africa (SETA) program.

Methods

The SETA health economic studies will rely on the platform for SETA typhoid surveillance in 4 African countries—Burkina Faso, Ethiopia, Ghana, and Madagascar. A COI and long-term socioeconomic study (LT-SES) will be its components. The COI will be assessed among blood culture–positive typhoid fever cases, blood culture–negative clinically suspected cases (clinical cases), and typhoid fever cases with pathognomonic gastrointestinal perforations (special cases). Repeated surveys using pretested questionnaires will be used to measure out-of-pocket expenses, quality of life, and the long-term socioeconomic impact. The cost of resources consumed for diagnosis and treatment will be collected at health facilities.

Results

Results from these studies will be published in peer-reviewed journals and presented at scientific conferences to make the data available to the wider health economics and public health research communities.

Conclusions

The health economic data will be analyzed to estimate the average cost per case, the quality of life at different stages of illness, financial stress due to illness, and the burden on the family due to caregiving during illness. The data generated are expected to be used in economic analysis and policy making on typhoid control interventions in sub-Saharan Africa.

Surgical Infections in Low- and Middle-Income Countries: A Global Assessment of the Burden and Management Needs

Background: The burden of surgical infections in low- and middle-income countries (LMICs) remains poorly defined compared with high-income countries. Although there are common infections necessitating surgery prevalent across the world, such as appendicitis and peptic ulcer disease, other conditions are more localized geographically. To date, comprehensive assessment of the burden of surgically treatable infections or sequelae of surgical infections in LMICs is lacking. Methods: We reviewed the literature to define the burden of surgical infections in LMICs and characterize the needs and challenges of addressing this issue. Results: Surgical infections comprise a broad range of diseases including intra-abdominal, skin and soft tissue, and healthcare-associated infections and other infectious processes. Treatment of surgical infections requires a functional surgical ecosystem, microbiology services, and appropriate and effective antimicrobial therapy. Systems must be developed and maintained to evaluate screening, prevention, and treatment strategies. Solutions and interventions are proposed focusing on reducing the burden of disease, improving surveillance, strengthening antibiotic stewardship, and enhancing the management of surgical infections. Conclusions: Surgical infections constitute a large burden of disease globally. Challenges to management in LMICs include a shortage of trained personnel and material resources. The increasing rate of antimicrobial drug resistance, likely related to antibiotic misuse, adds to the challenges. Development of surveillance, infection prevention, and antimicrobial stewardship programs are initial steps forward. Education is critical and should begin early in training, be an active process, and be sustained through regular programs.

Generating the Evidence for Typhoid Vaccine Introduction: Considerations for Global Disease Burden Estimates and Vaccine Testing Through Human Challenge

Typhoid fever has had a major impact on human populations, with the causative pathogen Salmonella enterica serovar Typhi implicated in many outbreaks through history. The current burden of disease is estimated at 11-18 million infections annually, with the majority of infections located in Africa and South Asia. Data that have been used to estimate burden are limited to a small number of blood-culture surveillance studies, largely from densely populated urban centers. Extrapolating these data to estimate disease burden within and across countries highlights the lack of precision in global figures. A number of approaches have been developed, characterizing different geographical areas by water-based risk factors for typhoid infection or broader measures of health and development to more accurately extrapolate incidence. Recognition of the substantial disease burden is essential for policy-makers considering vaccine introduction. Typhoid vaccines have been in development for >100 years. The Vi polysaccharide (ViPS) and Ty21a vaccines have had a World Health Organization (WHO) recommendation for programmatic use in countries with high burden for 10 years, with 1 ViPS vaccine also having WHO prequalification. Despite this, uptake and introduction of these vaccines has been minimal. The development of a controlled human infection model (CHIM) enabled the accelerated testing of the newly WHO-prequalified ViPS-tetanus toxoid protein conjugate vaccine, providing efficacy estimates for the vaccine, prior to larger field trials. There is an urgency to the global control of enteric fever due to the escalating problem of antimicrobial resistance. With more accurate burden of disease estimates and a vaccine showing efficacy in CHIM, that control is now a possibility.

Social and Economic Burden Associated With Typhoid Fever in Kathmandu and Surrounding Areas: A Qualitative Study

Typhoid fever is a significant contributor to infectious disease mortality and morbidity in low- and middle-income countries, particularly in South Asia. With increasing antimicrobial resistance, commonly used treatments are less effective and risks increase for complications and hospitalizations. During an episode of typhoid fever, households experience multiple social and economic costs that are often undocumented. In the current study, qualitative interview data from Kathmandu and surrounding areas provide important insights into the challenges that affect those who contract typhoid fever and their caregivers, families, and communities, as well as insight into prevention and treatment options for health providers and outreach workers. When considering typhoid fever cases confirmed by blood culture, our data reveal delays in healthcare access, financial and time costs burden on households, and the need to increase health literacy. These data also illustrate the impact of limited laboratory diagnostic equipment and tools on healthcare providers' abilities to distinguish typhoid fever from other febrile conditions and treatment challenges associated with antimicrobial resistance. In light of these findings, there is an urgent need to identify and implement effective preventive measures including vaccination policies and programs focused on at-risk populations and endemic regions such as Nepal.

Typhoid fever outbreak in the Democratic Republic of Congo: Case control and ecological study

During 2011 a large outbreak of typhoid fever affected an estimated 1430 people in Kikwit, Democratic Republic of Congo. The outbreak started in military camps in the city but then spread to the general population. This paper reports the results of an ecological analysis and a case-control study undertaken to examine water and other possible transmission pathways. Attack rates were determined for health areas and risk ratios were estimated with respect to spatial exposures. Approximately 15 months after the outbreak, demographic, environmental and exposure data were collected for 320 cases and 640 controls residing in the worst affected areas, using a structured interview questionnaire. Unadjusted and adjusted odds ratios were estimated. Complete data were available for 956 respondents. Residents of areas with water supplied via gravity on the mains network were at much greater risk of disease acquisition (risk ratio = 6.20, 95%CI 3.39–11.35) than residents of areas not supplied by this mains network. In the case control study, typhoid was found to be associated with ever using tap water from the municipal supply (OR = 4.29, 95% CI 2.20–8.38). Visible urine or faeces in the latrine was also associated with increased risk of typhoid and having chosen a water source because it is protected was negatively associated. Knowledge that washing hands can prevent typhoid fever, and stated habit of handwashing habits before cooking or after toileting was associated with increased risk of disease. However, observed associations between handwashing or plate-sharing with disease risk could very likely be due to recall bias. This outbreak of typhoid fever was strongly associated with drinking water from the municipal drinking water supply, based on the descriptive and analytic epidemiology and the finding of high levels of faecal contamination of drinking water. Future outbreaks of potentially waterborne disease need an integrated response that includes epidemiology and environmental microbiology during early stages of the outbreak.

There was a large outbreak of typhoid fever in Kikwit, DRC, in late 2011. The outbreak started in military camps in the city but then spread to the general population. Multiple investigations were undertaken to understand how the disease spread. The worst affected areas of the city were mapped and compared to the water network. In early 2013, demographic and exposure data were collected for 320 cases and 640 controls residing in the worst affected areas, using a structured interview questionnaire to try to better understand individual risk factors. Residents of areas with water supplied via a gravity fed network were about six times more likely to have been ill with typhoid fever than residents of areas not supplied by the mains network. The most important individual risk factor was ever using tap water. Visible urine or faeces increased risk of getting typhoid but having chosen a water source because it is protected was linked to lower risk. Not handwashing and regularly sharing plates of food were also linked to less illness, but these findings may be especially subject to recall bias. The water network was also found to be heavily contaminated, including with faecal bacteria of human origin in multiple microbiological studies. Spatial, microbiological and case-control studies all implicate the water supplies in Kikwit to be unsafe and linked to spread of typhoid fever in 2011. Improvements to the mains water network in Kikwit are urgently needed to prevent future typhoid fever outbreaks.

Typhoid fever: clinical presentation and associated factors in febrile patients visiting Shashemene Referral Hospital, southern Ethiopia

Objective

Although typhoid fever is a major public health problem in Ethiopia, data is not available in the study area. Therefore, this study aimed to determine the prevalence, clinical presentation at the time of diagnosis and associated factors of typhoid fever among febrile patients visiting Shashemene Referral Hospital, southern Ethiopia. A cross-sectional study was conducted from January 1, 2016, to October 30, 2016. Socio-demographic and clinical data were collected using a structured questionnaire. A blood sample was collected and inoculated into Tryptic soy broth.

Results

A total of 421 adult febrile patients suspected of typhoid fever were included in the study. Of these, the overall prevalence of culture-confirmed typhoid fever was 5.0% (21/421). The prevalence of typhoid fever was significantly associated with rural residence (8.4%). As compared to the urban resident, the rural resident was 3.6 times more likely found to have culture-confirmed typhoid fever. The prevalence of typhoid fever was significantly associated with those patients whose water source was spring 7 (12.3%) and river 7 (13.2%). All of those study participants who used treated water were culture negative. Fever for ≥ 5 days, abdominal pain, and skin rash independently predicted blood culture-confirmed typhoid fever.

Case Fatality Rate of Enteric Fever in Endemic Countries: A Systematic Review and Meta-analysis

Enteric fever is a febrile illness, occurring mostly in Asia and Africa, which can present as a severe and possibly fatal disease. Currently, a case fatality rate (CFR) of 1% is assumed when evaluating the global burden of enteric fever. Until now, no meta-analysis has been conducted to summarize mortality from enteric fever. Therefore, we conducted a systematic review and meta-analysis to aggregate all available evidence. We estimated an overall CFR of 2.49% (95% confidence interval, 1.65%-3.75%; n = 44), and a CFR in hospitalized patients of 4.45% (2.85%-6.88%; n = 21 of 44). There was considerably heterogeneity in estimates of the CFR from individual studies. Neither age nor antimicrobial resistance were significant prognostic factors, but limited data were available for these analyses. The combined estimate of the CFR for enteric fever is higher than previously estimated, and the evaluation of prognostic factors, including antimicrobial resistance, urgently requires more data.

Activation of coagulation and endothelium with concurrent impairment of anticoagulant mechanisms in patients with typhoid fever

OBJECTIVES

Typhoid fever caused by Salmonella Typhi remains a major burden worldwide. Gastrointestinal bleeding can be seen in up to 10 percent of patients and may be fatal. The coagulopathy, which may be the driver of this severe complication in patients with typhoid fever, however is ill defined. The aim of this study was to evaluate the activation of coagulation, anticoagulation, and fibrinolysis in patients with acute typhoid fever.

METHODS

Parameters of coagulation and fibrinolysis were measured in 28 hospitalized patients with culture-confirmed or PCR-confirmed typhoid fever and compared to 38 age- and sex-matched healthy volunteers.

RESULTS

Patients demonstrated activation of the coagulation system, as reflected by elevated in vitro thrombin generation and high plasma levels of fibrinogen, D-dimer and prothrombin fragment F1 + 2 in concert with consumption of coagulation factors resulting in a prolonged prothrombin-time and activated-partial-thromboplastin-time. Concurrently, the anticoagulant proteins, protein C and antithrombin, were significantly lower in comparison to healthy controls. Patients also demonstrated evidence of activation and inhibition of fibrinolysis and a marked activation of endothelial cells. The extent of coagulation activation was associated with the course of the disease, repeated testing during convalescence showed a return toward normal values.

CONCLUSIONS

Activation of coagulation is an important clinical feature of typhoid fever and is associated with severity of disease.

Clinical profile, antibiotic susceptibility pattern of bacterial isolates and factors associated with complications in culture-proven typhoid patients admitted to an urban hospital in Bangladesh

OBJECTIVES

Typhoid fever is one of the major causes of morbidity and mortality in typhoid endemic countries like Bangladesh. However, data on the clinical and microbiological profile as well as factors associated with complications of typhoid in Bangladesh are scarce. We intended to characterise the clinical and microbiological profile of culture-proven typhoid fever and to identify factors associated with complications.

METHODOLOGY

Retrospective analysis of clinical data from 431 patients with culture-confirmed typhoid fever admitted to Dhaka hospital of International Centre for Diarrhoeal Disease Research, Bangladesh, between January 2010 and December 2014. Clinical and microbiological profiles of the patients including age, sex, and duration of illness prior to hospital admission, haematological parameters and the antimicrobial resistance profile of the infecting isolate, duration of hospital stay and defervescence time were examined by logistic regression to identify the factors associated with complications.

RESULT

About one of three patients were children under 5 years, and 21.5% of them were severely malnourished. During hospitalisation, 17.4% patients developed complications; mainly encephalopathy (6.7%), ileus (6.5%) and pneumonia (3.5%). Among culture-positive cases, 28.3% isolates showed multidrug resistant (MDR) and more than 90% of isolates were resistant to nalidixic acid and had intermediate sensitivity to ciprofloxacin. Five isolates were resistant to azithromycin; all isolates were sensitive to cefixime and ceftriaxone. Complication was independently associated with duration of fever before admission (adjusted odds ratio: 0.85; 95% CI: 0.074-0.97; P < 0.05), thrombocytopenia on admission (AOR: 2.84; 95% CI: 01.06-7.57; P < 0.05), duration of hospital stay (AOR: 1.34; 95% CI: 1.15-1.57; P < 0.01) and defervescence time (AOR: 0.83; 95% CI: 0.70-0.99; P < 0.05).

CONCLUSION

The high prevalence of typhoid fever among under-five children and complications among hospitalised patients are matters of concern. Sensitivity of Salmonella Typhi to ceftriaxone and cefixime was better than to other conventional antibiotics. Shorter duration of fever and thrombocytopenia on admission can be considered as early signs of complications.

The Typhoid Vaccine Acceleration Consortium (TyVAC): Vaccine effectiveness study designs: Accelerating the introduction of typhoid conjugate vaccines and reducing the global burden of enteric fever. Report from a meeting held on 26-27 October 2016, Oxford, UK

Typhoid fever is estimated to cause between 11.9-26.9 million infections globally each year with 129,000-216,510 deaths. Access to improved water sources have reduced disease incidence in parts of the world but the use of efficacious vaccines is seen as an important public health tool for countries with a high disease burden. A new generation of Vi typhoid conjugate vaccines (TCVs), licensed for use in young children and expected to provide longer lasting protection than previous vaccines, are now available. The WHO Strategic Advisory Group of Experts on Immunization (SAGE) has convened a working group to review the evidence on TCVs and produce an updated WHO position paper for all typhoid vaccines in 2018 that will inform Gavi, the Vaccine Alliance's future vaccine investment strategies for TCVs. The Typhoid Vaccine Acceleration Consortium (TyVAC) has been formed through a $36.9 million funding program from the Bill & Melinda Gates Foundation to accelerate the introduction of TCVs into Gavi-eligible countries. In October 2016, a meeting was held to initiate planning of TCV effectiveness studies that will provide the data required by policy makers and stakeholders to support decisions on TCV use in countries with a high typhoid burden. Discussion topics included (1) the latest evidence and data gaps in typhoid epidemiology; (2) WHO and Gavi methods and data requirements; (3) data on TCV efficacy; (4) cost effectiveness analysis for TCVs from mathematical models; (5) TCV delivery and effectiveness study design. Specifically, participants were asked to comment on study design in 3 sites for which population-based typhoid surveillance is underway. The conclusion of the meeting was that country-level decision making would best be informed by the respective selected sites in Africa and Asia vaccinating children aged from 9-months to 15-years-old, employing either an individual or cluster randomized design with design influenced by population characteristics, transmission dynamics, and statistical considerations.

Typhoid intestinal perforation in developing countries: Still unavoidable deaths?

Typhoid fever is a public health challenge mostly concentrated in impoverished, overcrowded areas of the developing world, with lack of safe drinking and sanitation. The most serious complication is typhoid intestinal perforation (TIP), observed in 0.8% to 39%, with a striking rate difference between high-income and low-middle-income countries. Although the mortality rate consequent to TIP in resource-poor countries is improved in the last decades, it is still fluctuating from 5% to 80%, due to surgical- and not surgical-related constraints. Huge economic costs and long timelines are required to provide a short- to middle-term solution to the lack of safe water and sanitation. Inherent limitations of the currently available diagnostic tools may lead to under-evaluation as well as over-evaluation of the disease, with consequent delayed treatment or inappropriate, excessive antibiotic use, hence increasing the likelihood of bacterial resistance. There is a need for immunization programs in populations at greatest risk, especially in sub-Saharan Africa. Uniform surgical strategies and guidelines, on the basis of sound or prospective surgical studies and adapted to the local realities, are still lacking. Major drawbacks of the surgical treatment are the frequent delays to surgery, either for late diagnosis or for difficult transports, and the unavailable appropriate intensive care units in most peripheral facilities. As a consequence, poor patient’s conditions at presentation, severe peritoneal contamination and unsuitable postoperative care are the foremost determinant of surgical morbidity and mortality.

Prevalence of Salmonella Excretion in Stool: A Community Survey in 2 Sites, Guinea-Bissau and Senegal

BACKGROUND

Chronic and convalescent carriers play an important role in the transmission and endemicity of many communicable diseases. A high incidence of Salmonella enterica serovar Typhi and invasive nontyphoidal Salmonella (NTS) infection has been reported in parts of sub-Saharan Africa, yet the prevalence of Salmonella excretion in the general population is unknown.

METHODS

Stool specimens were collected from a random sample of households in 2 populations in West Africa: Bissau, Guinea-Bissau, and Dakar, Senegal. Stool was cultured to detect presence of Salmonella, and antimicrobial susceptibility testing was performed on the isolated organisms.

RESULTS

Stool was cultured from 1077 and 1359 individuals from Guinea-Bissau and Senegal, respectively. Salmonella Typhi was not isolated from stool samples at either site. Prevalence of NTS in stool samples was 24.1 (95% confidence interval [CI], 16.5-35.1; n = 26/1077) per 1000 population in Guinea-Bissau and 10.3 (95% CI, 6.1-17.2; n = 14/1359) per 1000 population in Senegal.

CONCLUSIONS

Evidence of NTS excretion in stool in both study populations indicates a possible NTS transmission route in these settings.

The unrecognized burden of typhoid fever

INTRODUCTION

Typhoid fever (TF), caused by Salmonella enterica serovar Typhi, is the most common cause of enteric fever, responsible for an estimated 129,000 deaths and more than 11 million cases annually. Although several reviews have provided global and regional TF disease burden estimates, major gaps in our understanding of TF epidemiology remain. Areas covered: We provide an overview of the gaps in current estimates of TF disease burden and offer suggestions for addressing them, so that affected communities can receive the full potential of disease prevention offered by vaccination and water, sanitation, and hygiene interventions. Expert commentary: Current disease burden estimates for TF do not capture cases from certain host populations, nor those with atypical presentations of TF, which may lead to substantial underestimation of TF cases and deaths. These knowledge gaps pose major obstacles to the informed use of current and new generation typhoid vaccines.

Live Attenuated Human Salmonella Vaccine Candidates: Tracking the Pathogen in Natural Infection and Stimulation of Host Immunity

Salmonellosis, caused by members of the genus Salmonella, is responsible for considerable global morbidity and mortality in both animals and humans. In this review, we will discuss the pathogenesis of Salmonella enterica serovar Typhi and Salmonella enterica serovar Typhimurium, focusing on human Salmonella infections. We will trace the path of Salmonella through the body, including host entry sites, tissues and organs affected, and mechanisms involved in both pathogenesis and stimulation of host immunity. Careful consideration of the natural progression of disease provides an important context in which attenuated live oral vaccines can be rationally designed and developed. With this in mind, we will describe a series of attenuated live oral vaccines that have been successfully tested in clinical trials and demonstrated to be both safe and highly immunogenic. The attenuation strategies summarized in this review offer important insights into further development of attenuated vaccines against other Salmonella for which live oral candidates are currently unavailable.

Typhoid perforation: Post-operative Intensive Care Unit care and outcome

BACKGROUND

Typhoid perforation ileitis is a serious complication of typhoid fever, a common and unfortunate health problem in a resource-poor country like Nigeria. Following bowel perforation, treatment is usually by simple closure or bowel resection and anastomosis after adequate aggressive fluid resuscitation and electrolyte correction. Postoperatively, some of these patients do require management in Intensive Care Unit (ICU) on account of sepsis or septic shock and to improve survival.

PATIENTS AND METHODS

This is a prospective observational study in which 67 consecutive patients who had exploratory laparotomy for typhoid perforation between August 2009 and October 2012 in the main operating theatre of the University College Hospital, Ibadan, were studied. The attending anaesthetists had the freedom of choosing the appropriate anaesthetic drugs depending on the patients' clinical condition. The reason for admission into the ICU, the types of organ support required and outcomes were recorded.

RESULTS

Twenty-five patients (37.3%) out of 67 required critical care. Reasons for admission among others included poor respiratory effort, hypotension, septic shock and delayed recovery from anaesthesia. Twenty-one patients (84%) required mechanical ventilation with a mean duration of 2.14 days (range 1-5 days). Fourteen patients required ionotropic support and the length of ICU stay ranged from 1 to 15 days (mean 4.32 days). Nineteen patients (76%) were successfully managed and discharged to the ward while 24% (6 patients) mortality rate was recorded.

CONCLUSION

This study showed high rate of post-operative ICU admission in patients with typhoid perforation with a high demand for critical care involving mechanical ventilation and ionotropic support. In centres that manage patients presenting with typhoid ileitis and perforation, post-operative critical care should be available.

Salmonella Bacteremia Among Children in Central and Northwest Nigeria, 2008-2015

BACKGROUND

Etiologic agents of childhood bacteremia remain poorly defined in Nigeria. The absence of such data promotes indiscriminate use of antibiotics and delays implementation of appropriate preventive strategies.

METHODS

We established diagnostic laboratories for bacteremia surveillance at regional sites in central and northwest Nigeria. Acutely ill children aged <5 years with clinically suspected bacteremia were evaluated at rural and urban clinical facilities in the Federal Capital Territory, central region and in Kano, northwest Nigeria. Blood was cultured using the automated Bactec incubator system.

RESULTS

Between September 2008 and April 2015, we screened 10,133 children. Clinically significant bacteremia was detected in 609 of 4051 (15%) in the northwest and 457 of 6082 (7.5%) in the central region. Across both regions, Salmonella species account for 24%-59.8% of bacteremias and are the commonest cause of childhood bacteremia, with a predominance of Salmonella enterica serovar Typhi. The prevalence of resistance to ampicillin, chloramphenicol, and cotrimoxazole was 38.11%, with regional differences in susceptibility to different antibiotics but high prevalence of resistance to readily available oral antibiotics.

CONCLUSIONS

Salmonella Typhi is the leading cause of childhood bacteremia in central Nigeria. Expanded surveillance is planned to define the dynamics of transmission. The high prevalence of multidrug-resistant strains calls for improvement in environmental sanitation in the long term and vaccination in the short term.

Which cause of diffuse peritonitis is the deadliest in the tropics? A retrospective analysis of 305 cases from the South-West Region of Cameroon

Background

Acute diffuse peritonitis is a common surgical emergency worldwide and a major contributor to non-trauma related death toll. Its causes vary widely and are correlated with mortality. Community acquired peritonitis seems to play a major role and is frequently related to hollow viscus perforation. Data on the outcome of peritonitis in the tropics are scarce. The aim of this study is to analyze the impact of tropic latitude causes of diffuse peritonitis on morbidity and mortality.

Methods

We retrospectively reviewed the records of 305 patients operated on for a diffuse peritonitis in two regional hospitals in the South-West Region of Cameroon over a 7 years period. The contributions of various causes of peritonitis to morbidity and mortality were analyzed.

Results

The diagnosis of diffuse peritonitis was suggested on clinical ground only in more than 93 % of cases. The most common causes of diffuse peritonitis included peptic ulcer perforation (n = 69), complications of acute appendicitis (n = 53) and spontaneous perforations of the terminal ileum (n = 43). A total of 142 complications were recorded in 96 patients (31.5 % complication rate). The most common complications included wound dehiscence, sepsis, prolonged paralytic ileus and multi-organ failure. Patients with typhoid perforation of the terminal ileum carried a significantly higher risk of developing a complication (p = 0.002). The overall mortality rate was 15.1 %. The most common cause of death was septic shock. Differential analysis of mortality of various causes of peritonitis indicated that the highest contributors to death toll were typhoid perforation of terminal ileum (34.7 % of deaths), post-operative peritonitis (19.5 %) and peptic ulcer perforation (15.2 %).

Conclusion

The diagnosis of diffuse peritonitis can still rely on clinical assessment alone in the absence of sophisticated imaging tools. Peptic ulcer and typhoid perforations are still major contributors to death toll. Patients presenting with these conditions require specific attention and prevention policies must be reinforced.

Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment

BACKGROUND

No access to safe water is an important risk factor for typhoid fever, yet risk-level heterogeneity is unaccounted for in previous global burden estimates. Since WHO has recommended risk-based use of typhoid polysaccharide vaccine, we revisited the burden of typhoid fever in low-income and middle-income countries (LMICs) after adjusting for water-related risk.

METHODS

We estimated the typhoid disease burden from studies done in LMICs based on blood-culture-confirmed incidence rates applied to the 2010 population, after correcting for operational issues related to surveillance, limitations of diagnostic tests, and water-related risk. We derived incidence estimates, correction factors, and mortality estimates from systematic literature reviews. We did scenario analyses for risk factors, diagnostic sensitivity, and case fatality rates, accounting for the uncertainty in these estimates and we compared them with previous disease burden estimates.

FINDINGS

The estimated number of typhoid fever cases in LMICs in 2010 after adjusting for water-related risk was 11·9 million (95% CI 9·9-14·7) cases with 129 000 (75 000-208 000) deaths. By comparison, the estimated risk-unadjusted burden was 20·6 million (17·5-24·2) cases and 223 000 (131 000-344 000) deaths. Scenario analyses indicated that the risk-factor adjustment and updated diagnostic test correction factor derived from systematic literature reviews were the drivers of differences between the current estimate and past estimates.

INTERPRETATION

The risk-adjusted typhoid fever burden estimate was more conservative than previous estimates. However, by distinguishing the risk differences, it will allow assessment of the effect at the population level and will facilitate cost-effectiveness calculations for risk-based vaccination strategies for future typhoid conjugate vaccine.

Perforated peptic ulcer

Perforated peptic ulcer is a common emergency condition worldwide, with associated mortality rates of up to 30%. A scarcity of high-quality studies about the condition limits the knowledge base for clinical decision making, but a few published randomised trials are available. Although Helicobacter pylori and use of non-steroidal anti-inflammatory drugs are common causes, demographic differences in age, sex, perforation location, and underlying causes exist between countries, and mortality rates also vary. Clinical prediction rules are used, but accuracy varies with study population. Early surgery, either by laparoscopic or open repair, and proper sepsis management are essential for good outcome. Selected patients can be managed non-operatively or with novel endoscopic approaches, but validation of such methods in trials is needed. Quality of care, sepsis care bundles, and postoperative monitoring need further assessment. Adequate trials with low risk of bias are urgently needed to provide better evidence. We summarise the evidence for perforated peptic ulcer management and identify directions for future clinical research.

Typhoid Intestinal Perforations: Has the Clinical Importance Decreased in Eastern Anatolia for 36 Years?

OBJECTIVE

Typhoid fever (TF) is an important health problem in developing countries, and typhoid intestinal perforation (TIP) is a serious complication of TF. The present report aims to determine the clinical importance of TIPs for the last 36 years in our region, eastern Anatolia.

MATERIALS AND METHODS

The clinical records of 84 surgically treated cases with TIPs were reviewed retrospectively.

RESULTS

When the last 36-year period was sectioned by 6-year periods, the distribution of TIPs was found as 39 (46.4% of total), 31 (36.9%), 7 (8.3%), 4 (4.8%), 2 (2.4%) and 1 (1.2%), respectively. The mean age of the patients was 37.1 years (range: 7-68 years), and 66 patients (78.6%) were male. As a surgical procedure, 34 patients (40.5%) had primary repair, 9 (10.7%) had wedge resection with primary repair, 9 (10.7%) had resection with primary anastomosis, 28 (33.3%) had resection with ileostomy, and 4 (4.8%) had exteriorization. Complications were seen in 71 patients (84.5%), while the mortality rate was 10.7% (9 patients).

CONCLUSION

Although eastern Anatolia is an endemic region for TF, a certain decrease in the incidence of TIPs was found for the last 36 years. Keeping in mind the TIP, patients with TF may improve the prognosis of this serious disease.

The case for a typhoid vaccine probe study and overview of design elements

Recent advances in typhoid vaccine, and consideration of support from Gavi, the Vaccine Alliance, raise the possibility that some endemic countries will introduce typhoid vaccine into public immunization programs. This decision, however, is limited by lack of definitive information on disease burden. We propose use of a vaccine probe study approach. This approach would more clearly assess the total burden of typhoid across different syndromic groups and account for lack of access to care, poor diagnostics, incomplete laboratory testing, lack of mortality and intestinal perforation surveillance, and increasing antibiotic resistance. We propose a cluster randomized trial design using a mass immunization campaign among all age groups, with monitoring over a 4-year period of a variety of outcomes. The primary outcome would be the vaccine preventable disease incidence of prolonged fever hospitalization. Sample size calculations suggest that such a study would be feasible over a reasonable set of assumptions.

Evaluation of TUBEX-TF and OnSite Typhoid IgG/IgM Combo rapid tests to detect Salmonella enterica serovar Typhi infection during a typhoid outbreak in Harare, Zimbabwe

Background

Salmonella enterica serovar Typhi, the causative agent of typhoid, is endemic in most parts of the world especially in Africa. Reliable and rapid diagnosis of the bacterium is therefore critical for confirmation of all suspected typhoid cases. In many parts of Zimbabwe, laboratory capacity to isolate the microorganism by culture method as a way of diagnosis has limitations. In this study, two rapid serological kits, TUBEX-TF and OnSite Typhoid IgG/IgM Combo, were evaluated for possible expeditious diagnosis of Salmonella enterica serovar Typhi infection during a typhoid outbreak in Zimbabwe.

Methods

Blood was collected from patients with clinical signs and symptoms of typhoid in Harare, Zimbabwe during an outbreak. The standard culture method was used to diagnose the disease. Two rapid kits, the TUBEX-TF and OnSite Typhoid IgG/IgM Combo, were also used in parallel to diagnose typhoid according to manufacturers’ instructions. The diagnostic accuracy of the two kits was evaluated using the culture method as the gold standard.

Results

From all the cases diagnosed by the blood culture (n = 136), we enrolled 131 patients for the TUBEX-TF and 136 for the OnSite Typhoid IgG/IgM Combo tests. With the culture method as a reference standard, we found that TUBEX-TF test was 100% sensitive and 94.12% specific, with 63.16% positive and 100% negative predictive values (NPVs) and the OnSite Typhoid IgG/IgM Combo test was 100% sensitive and 94.35% specific, with 63.16% positive and 100% NPVs.

Conclusion

Our results indicated that TUBEX-TF and OnSite Typhoid IgG/IgM Combo rapid tests were useful tools for the rapid diagnosis of Salmonella enterica serovar Typhi infection during typhoid outbreaks in Zimbabwe. The tests performed very well in laboratory evaluations of blood culture-confirmed typhoid cases in Harare, Zimbabwe.