Rapid immunochromatographic tests for the diagnosis of chronic Chagas disease in at-risk populations: A systematic review and meta-analysis

Background Despite of a high disease burden, mainly in Latin America, Chagas disease (CD) is underdiagnosed and undertreated. Rapid diagnostic tests (RDTs) might improve the access to diagnosis. The aim of this study is to review the accuracy of commercially available RDTs used in field conditions for the diagnosis of chronic CD in populations at risk, in endemic and non-endemic countries. Methods/Principal findings We undertook a comprehensive search of the following databases: PubMed, SCOPUS, LILACS (last up-date on the 01st July, 2017), without language or date limits. Non-electronic sources have been also searched. This review included clinical studies with cohort recruitment of individuals at risk of T. cruzi exposure, without age limits; adequate reference standards for the diagnosis of CD. We excluded case-control studies and those testing RDTs during acute CD. Data on test accuracies were pooled through a bivariate random-effects model. Only one index test was evaluated separately. Geographical area, commercial brand, disease prevalence, study size, and risk of bias were explored as possible source of heterogeneity. Values of sensitivity and specificity were computed to obtain summary positive/negative likelihood ratios, and summary diagnostic odds ratio. Ten studies were included on six different immunochromatographic RDTs. The pooled sensitivity and specificity of the RDTs resulted 96.6% (95% CI 91.3–98.7%) and 99.3% (95% CI 98.4–99.7%), respectively. Test accuracy was particularly good in endemic areas (98.07%/99.03% of sensitivity/specificity, respectively). One test (Stat-Pak) showed an overall sensitivity of 97% (95% CI 87.6–99.3) and specificity of 99.4% (95% CI 98.6–99.8). Conclusions/Significance RDTs demonstrated to be sufficiently accurate to recommend their use for screening in endemic areas, even as stand-alone tests. This approach might increase the accessibility to the diagnosis. However, an additional confirmatory test in case of positive result remains a prudent approach

StrongNet: An International Network to Improve Diagnostics and Access to Treatment for Strongyloidiasis Control

Strongyloidiasis is a disease caused by an infection with a soil-transmitted helminth that affects, according to largely varying estimates, between 30 million and 370 million people worldwide [1,2]. Not officially listed as a neglected tropical disease (NTD), strongyloidiasis stands out as particularly overlooked [3]. Indeed, there is a paucity of research and public health efforts pertaining to strongyloidiasis. Hence, clinical, diagnostic, epidemiologic, treatment, and control aspects are not adequately addressed to allow for an effective management of the disease, both in clinical medicine and in public health programs [4]. The manifold signs and symptoms caused by Strongyloides stercoralis infection, coupled with the helminth’s unique potential to cause lifelong, persistent infection, make strongyloidiasis relevant beyond tropical and subtropical geographic regions, where, however, most of the disease burden is concentrated. Indeed, strongyloidiasis is acquired through contact with contaminated soil, and the infection is, thus, primarily transmitted in areas with poor sanitation, inadequate access to clean water, and lack of hygiene

Strongyloides stercoralis: a plea for action.

This paper argues that enough is now known on this neglected parasite to justify starting specific control measures

Strongyloides stercoralis: a plea for action

More than one century later, the key issues regarding this parasite (subsequently renamed Strongyloides stercoralis) are essentially the same, and although researchers have recently given more attention to this infection, systematic action plans still lag behind. There is widespread agreement in the scientific community that its prevalence is largely underestimated [2]. The current estimate of 30 to 100 million infected persons in the world dates back to review articles published between 1989 and 1996 [3], [4], and is cited by most subsequent papers. These figures were mostly based on surveys aimed at defining the prevalence of parasitic infections, without using adequate diagnostic techniques for S. stercoralis. For example, Kato-Katz, a technique that is commonly used in surveys aiming to assess intestinal helminth infections [5], is poorly sensitive for this parasite. Larvae of S. stercoralis in stool are often scanty, and therefore they are most often missed by this technique that examines a small amount of faeces (between 20 and 50 mg, depending on the template). Larvae can be detected by this technique only occasionally, when the larval output is particularly high [6]. More reliable prevalence estimates have been made by geographically confined surveys, using alternative faecal-based diagnostic methods that are much more sensitive such as Baermann or Koga agar plate culture [7], [8]. Serology (ELISA or IFAT) is even more sensitive, but its specificity is less well defined. Problems of cross-reactivity seem to arise especially in areas where other nematodes, particularly filariae, are also endemic. New and promising tools such as serologic methods based on recombinant antigens or PCR are also available in some referral centers. However, the optimal diagnostic strategy, both for epidemiological surveys and for individual diagnosis and screening, has yet to be defined and certainly deserves further researc

African Trypanosomiasis Gambiense, Italy

African trypanosomiasis caused by Trypanosoma brucei gambiense has not been reported in Italy. We report 2 cases diagnosed in the summer of 2004. Theses cases suggest an increased risk for expatriates working in trypanosomiasis-endemic countries. Travel medicine clinics should be increasingly aware of this potentially fatal disease

Diagnostic evaluation of people with hypertension in low income country: cohort study of “essential” method of risk stratification

Objectives To explore the predictive power of a risk stratification method for people with hypertension based on “essential” procedures (that is, available in economically less developed areas of the world), comparing it in the same population with the results given by the method suggested by the 1999 World Health Organization-International Society of Hypertension (WHO-ISH) guidelines

Long-Term Outcomes of a Cohort of Hypertensive Subjects in Rural Ecuador

Background: In contrast with the abundance of global epidemiological descriptive data on cardiovascular diseases and their risk factors, information on the outcomes of real populations prospectively followed up in their life and care settings is much rarer, especially in low-income countries.Objectives: This study sought to evaluate the feasibility and the overall results of a hypertension control program, based mainly on a network of community nonprofessional health promoters, in the poor rural region of Borbon (Ecuador).Methods: This is a prospective cohort study describing the results of a program of hypertension diagnosis, treatment and follow-up from 2004 to 2015 in the area, carried out mainly by the health promoters.Results: The number of hypertensive patients identified and followed over the years increased from 1,024 in 2004 to 1,733 in 2015. The percentage of patients with no visits during a year was reduced to <10%, whereas the proportion of hypertensive subjects attending all 4 scheduled annual checks approached and, in some years, exceeded 50%. From 2004 to 2015, the proportion of patients at high or very high cardiovascular risk progressively decreased from 26.6% in 2004 to 17.5% in 2015 (p for trend <0.01), whereas the proportion of hypertensive patients at low or very low risk increased from 30.4% in 2004 to 45.0% in 2015 (p for trend <0.01).Conclusions: In a poor, disadvantaged area, a strategy of control mainly based on the involvement and responsibility of community health promoters (with health professionals as supporters more than direct actors) can achieve adequate follow-up of the population of hypertensive patients and improve their global cardiovascular risk level.HighlightsHypertension is increasingly recognized as a major cause of cardiovascular mortality and morbidity also in low-income countries, but little is known about how to face this common risk factor with limited economic and professional resources, particularly in remote rural areas.In a poor disadvantaged area of the equatorial forest, hypertension diagnosis and control, mainly by nonprofessional local health promoters, can ensure adequate follow-up of the hypertensive population.Over more than 10 years, the global cardiovascular risk has progressively declined.Noncommunicable chronic diseases such as hypertension can be managed by giving local health promoters a pivotal role

Randomized Clinical Trial on Ivermectin versus Thiabendazole for the Treatment of Strongyloidiasis

Strongyloidiasis is the infection caused by the worm Strongyloides stercoralis. Due to its peculiar life cycle Strongyloides may remain indefinitely in the host, if not effectively cured. Although the disease is usually mild, in case of weakening of the host's immune defenses the worm may invade virtually all organs and tissues (disseminated strongyloidiasis, almost invariably fatal). The treatment must then reach the goal of the complete elimination of the parasite. Small size clinical trials showed similar, high efficacy of the two drugs ivermectin (used as a single dose) and thiabendazole (used twice daily for two consecutive days). All trials used as the criterion for cure the absence of larvae in stool exams. The latter however may easily miss the infection, falsely suggesting that the infection has been cured. This trial, using a test detecting specific Strongyloides antibodies as an additional and more sensitive diagnostic tool, confirms previous reports: the two drugs have similar efficacy but ivermectin is better tolerated and is therefore the first choice. However the cure rate was lower than 70% for the standard, single dose. The authors then conclude that a larger, multi center trial is needed to find the optimal dose schedule of ivermectin

Comparison of S. stercoral is Serology Performed on Dried Blood Spotsand on Conventional Serum Samples

Background: Dried blood spots (DBS) are used for epidemiological surveys on infectious diseases in settings where limited resources are available. In fact, DBS can help to overcome logistic difficulties for the collection, transport and storage of biological specimens. Objective: To evaluate the accuracy of Strongyloides stercoralis serology performed on DBS. Methods: A survey was proposed to children attending a school in the village of Borbon, Ecuador, and to their parents/guardians. Each participant gave consent to the collection of both serum and DBS specimens. DBS absorbed on filter papers were analyzed with a commercially available ELISA test for S. stercoralis antibodies, as well as with standard serology. The agreement between the two methods was assessed through the Cohens kappa coefficient. Results: The study sample was composed of 174 children and 61 adults, for a total of 235 serum and 235 DBS samples. The serology was positive in 31/235 (13%) serum samples, and in 27/235 (11%) DBS: 4 samples resulted discordant (positive at standard serology). Cohens kappa coefficient was 0.921 (95% CI 0.845 0.998), indicating a high rate of concordance. Conclusion: DBS are suitable for in field-surveys requiring serological testing for S. stercoralis