Challenges and Opportunities for Typhoid Fever Control: A Call for Coordinated Action.

The burden of enteric fever caused by Salmonella enterica serovars Typhi and Paratyphi is substantial and has high impact in toddlers and young children. This burden is relatively well documented in Asia, and this supplement provides new data on the substantial burden in several sub-Saharan African countries. Challenges in standardized surveillance and imperfect diagnostic tools have resulted in patchy local disease data, which are not well acknowledged or integrated into local country evidence and health awareness for decision making. There is a need to strengthen diagnostics for the generation of burden data in country. Furthermore, the guidelines and training for treatment of enteric fever cases in Africa are sorely needed to help mitigate the inappropriate use of antimicrobial treatment. Classic water safety and access to sanitation development remain powerful tools for the control of typhoid fever, yet the huge economic costs and long timelines are unlikely to provide a short- to middle-term solution. Emerging threats, including multidrug resistance and increasing urbanization in regions such as sub-Saharan Africa, warrant focused attention to shorter-term interventions including immunization, and must include vaccine strategies with the new typhoid conjugate vaccines.

Environmental enteric dysfunction: pathogenesis, diagnosis, and clinical consequences.

Stunting is common in young children in developing countries, and is associated with increased morbidity, developmental delays, and mortality. Its complex pathogenesis likely involves poor intrauterine and postnatal nutrition, exposure to microbes, and the metabolic consequences of repeated infections. Acquired enteropathy affecting both gut structure and function likely plays a significant role in this outcome, especially in the first few months of life, and serve as a precursor to later interactions of infection and malnutrition. However, the lack of validated clinical diagnostic criteria has limited the ability to study its role, identify causative factors, and determine cost-effective interventions. This review addresses these issues through a historical approach, and provides recommendations to define and validate a working clinical diagnosis and to guide critical research in this area to effectively proceed. Prevention of early gut functional changes and inflammation may preclude or mitigate the later adverse vicious cycle of malnutrition and infection.

Use of the lactulose to mannitol ratio to evaluate childhood environmental enteric dysfunction: a systematic review.

Childhood gut dysfunction (enteropathy) is common in resource-poor environments. Stunting is its presumed major consequence. Identification of biomarkers of gut dysfunction could identify the presence of, and, ideally, assess interventions for, enteropathy. Classically, enteropathy has been identified histopathologically. However, less invasive assays may be more sensitive for detecting earlier perturbations reflecting specific functional derangements. The most commonly used test has been the urinary lactulose to mannitol ratio (L:M), which primarily assesses gut leakiness, and which also measures absorption. We systematically reviewed the L:M literature published from 2000 to 2010 pertinent to children in developing country settings, and identified 25 relevant publications representing heterogeneous studies. We conclude that the L:M test has many attributes, including reflecting 2 physiologic processes (absorption and permeability) and likely correlation with growth failure consequent to child gut dysfunction. However, improved test technical performance, data reporting, and correlation with host phenotypes are needed to maximize the utility of this test.

Tuberculosis serodiagnosis in a predominantly HIV-infected population of hospitalized patients with cough, Botswana, 2002.

A sensitive and accurate tuberculosis (TB) serodiagnostic test would aid in the control of TB, but results of current tests are relatively unreliable for persons infected with human immunodeficiency virus (HIV). We evaluated a new prototype immunochromatographic strip test and 5 commercially available serodiagnostic TB tests in a prospective study comprised of 465 consecutively enrolled patients with suspected TB from 2 hospitals in Botswana. Consenting adults underwent HIV testing, >/=2 sputum smears and cultures, and mycobacterial blood culture. Patients were defined as having TB on the basis of any positive smear or culture. Between January and September 2002, 465 of 498 consecutive patients consented to enrollment. A total of 384 patients (83%) were infected with HIV, and 175 (38%) had TB; the mycobacterial blood culture was the sole source of diagnosis for 26 patients (15%) with TB. Among the tests evaluated, the sensitivity was 0%-63%, the specificity was 39%-99%, the positive predictive value was 0%-39%, and the negative predictive value was 63%-65%. We conclude that the serodiagnostic tests evaluated in this study lacked sufficient sensitivity as sole tests for TB in this population.