Strongyloidiasis is frequently under diagnosed since many infections remain asymptomatic and conventional diagnostic tests based on parasitological examination are not sufficiently sensitive. Serology is useful but is still only available in reference laboratories. The need for improved diagnostic tests in terms of sensitivity and specificity is clear, particularly in immunocompromised patients or candidates to immunosuppressive treatments. This review aims to evaluate both conventional and novel techniques for the diagnosis of strongyloidiasis as well as available cure markers for this parasitic infection. The search strategy was based on the data-base sources MEDLINE, Cochrane Library Register for systematic review, EmBase, Global Health and LILACS and was limited in the search string to articles published from 1960 to August 2012 and to English, Spanish, French, Portuguese and German languages. Case reports, case series and animal studies were excluded. 2003 potentially relevant citations were selected for retrieval, of which 1649 were selected for review of the 143 were eligible for final inclusion. Sensitivity of microscopic-based techniques is not good enough, particularly in chronic infections. Furthermore, techniques such as Baermann or agar plate culture are cumbersome and time-consuming and several specimens should be collected on different days to improve the detection rate. Serology is a useful tool but it might overestimate the prevalence of disease due to cross-reactivity with other nematode infections and its difficulty distinguishing recent from past (and cured) infections. To evaluate treatment efficacy is still a major concern because direct parasitological methods might overestimate it and the serology has not yet been well evaluated; even if there is a decline in antibody titres after treatment, it is slow and it needs to be done at 6 to 12 months after treatment which can cause a substantial loss to follow-up in a clinical trial. Strongyloidiasis is a parasitic infection that can occur in any place of the world. It is not easy to diagnose because the conventional tests are not good enough, especially in individuals that do not present any symptoms of the disease. This is of particular importance in immunocompromised patients, because the disease can spread causing a disseminated disease which can be fatal. In this study, authors review both conventional and novel techniques for the diagnosis of strongyloidiasis. Parasitological examinations based on the detection of the parasite in faeces are the most common techniques used until now in the majority of laboratories. However, they have some disadvantages because most of the best techniques are cumbersome and time consuming and several stool samples have to be collected to improve the diagnosis. New techniques such as the serology which is performed through a blood test are becoming available, but they have still some problems; the test sometimes does not accurately differentiate strongyloidiasis from other helminthic diseases. Another major problem in this disease is to evaluate if patient is cured after the treatment. Parasitological methods can fail to detect treatment failure, and serology has not yet been well evaluated in this context.

Few studies have assessed the burden of Chagas disease in non-endemic countries and most of them are based on prevalence estimates from Latin American (LA) countries that likely differ from the prevalence in migrants living in Europe. The aim of this study was to systematically review the existing data informing current understanding of the prevalence of Chagas disease in LA migrants living in European countries. We conducted a systematic review and meta-analysis of studies reporting prevalence of Chagas disease in European countries belonging to the European Union (EU) before 2004 in accordance with the MOOSE guidelines and based on the database sources MEDLINE and Global Health. No restrictions were placed on study date, study design or language of publication. The pooled prevalence was estimated using random effect models based on DerSimonian & Laird method. We identified 18 studies conducted in five European countries. The random effect pooled prevalence was 4.2% (95%CI:2.2-6.7%); and the heterogeneity of Chagas disease prevalence among studies was high (I2 = 97%,p<0.001). Migrants from Bolivia had the highest prevalence of Chagas disease (18.1%, 95%CI:13.9–22.7%). Prevalence of Chagas in LA migrants living in Europe is high, particularly in migrants from Bolivia and Paraguay. Data are highly heterogeneous dependent upon country of origin and within studies of migrants from the same country of origin. Country-specific prevalence differs from the estimates available from LA countries. Our meta-analysis provides prevalence estimates of Chagas disease that should be used to estimate the burden of disease in European countries. Chagas disease is emerging in European countries due to the migration flows from Latin-American endemic countries to Europe, particularly to southern countries. Some studies have evaluated the prevalence of this disease in several European countries although these estimates are based on national population prevalence rates from countries of origin and the estimated size of the corresponding migrant population. The objective of this study is to review the studies about the prevalence of Chagas disease in Latin American migrants living in European countries. Our meta-analysis provides prevalence estimates of Chagas disease that should be used to estimate the burden of disease in European countries. This accurate data about country specific prevalence of Chagas disease could be used to evaluate the cost-effectiveness of screening programmes and also could help policy makers to design health interventions concerning Chagas disease.

Strongyloidiasis is commonly a clinically unapparent, chronic infection, but immuno suppressed subjects can develop fatal disease. We carried out a review of literature on hyperinfection syndrome (HS) and disseminated strongyloidiasis (DS), in order to describe the most challenging aspects of severe strongyloidiasis.

The diagnosis of Strongyloides stercoralis (S. stercoralis) infection is hampered by the suboptimal sensitivity of fecal-based tests. Serological methods are believed to be more sensitive, although assessing their accuracy is difficult because of the lack of sensitivity of a fecal-based reference (“gold”) standard. The sensitivity and specificity of 5 serologic tests for S. stercoralis (in-house IFAT, NIE-ELISA and NIE-LIPS and the commercially available Bordier-ELISA and IVD-ELISA) were assessed on 399 cryopreserved serum samples. Accuracy was measured using fecal results as the primary reference standard, but also using a composite reference standard (based on a combination of tests). According to the latter standard, the most sensitive test was IFAT, with 94.6% sensitivity (91.2–96.9), followed by IVD-ELISA (92.3%, 87.7–96.9). The most specific test was NIE-LIPS, with specificity 99.6% (98.9–100), followed by IVD-ELISA (97.4%, 95.5–99.3). NIE-LIPS did not cross-react with any of the specimens from subjects with other parasitic infections. NIE-LIPS and the two commercial ELISAs approach 100% specificity at a cut off level that maintains ≥70% sensitivity. NIE-LIPS is the most accurate serologic test for the diagnosis of S. stercoralis infection. IFAT and each of the ELISA tests are sufficiently accurate, above a given cut off, for diagnosis, prevalence studies and inclusion in clinical trials. The diagnosis of Strongyloides stercoralis infection is usually made by finding larvae of the parasite in the feces. The larval output is orders of magnitude lower than, say, the egg output of Ancylostoma duodenale, therefore the sensitivity of conventional techniques is poor. Sensitivity is enhanced by specific techniques, but the infection can still be missed. Several serologic methods (Strongyloides antibody detection in blood) are considered more sensitive, but they have been assessed so far with fecal tests as the gold standard, which is obviously unsatisfactory considering, precisely, their suboptimal sensitivity. Using a bank of sera from patients surely infected, not infected or doubtful, we assessed the accuracy of five different serologic tests also using a composite reference standard, obtained by combining the results of different tests. The recently developed NIE-LIPS resulted virtually 100% specific, with sensitivity >80%. Two commercially available ELISA tests were also highly specific above a given cut-off. Cross reactions with other parasitic infections were rarer than in previous studies. In conclusion, serologic tests are accurate tools, both for diagnostic purposes and for prevalence studies. Whether or not they can also be reliable markers of cure is currently under study.

Coordinating resources to assess and improve health status of migrants from Latin America (COHEMI) project study group, European Commission, Health Cooperation Work Programme, FP7 (GA-261495),

Global migration from regions where strongyloidiasis and schistosomiasis are endemic to non-endemic countries has increased the potential individual and public health effect of these parasitic diseases. We aimed to estimate the prevalence of these infections among migrants to establish which groups are at highest risk and who could benefit from screening. We did a systematic review and meta-analysis of strongyloidiasis and schistosomiasis prevalence among migrants born in endemic countries. Original studies that included data for the prevalence of Strongyloides or Schistosoma antibodies in serum or the prevalence of larvae or eggs in stool or urine samples among migrants originating from countries endemic for these parasites and arriving or living in host countries with low endemicity-specifically the USA, Canada, Australia, New Zealand, Israel, and 23 western European countries-were eligible for inclusion. Pooled estimates of the prevalence of strongyloidiasis and schistosomiasis by stool or urine microscopy for larvae or eggs or serum antibodies were calculated with a random-effects model. Heterogeneity was explored by stratification by age, region of origin, migrant class, period of study, and type of serological antigen used. 88 studies were included. Pooled strongyloidiasis seroprevalence was 12·2% (95% CI 9·0-15·9%; I2 96%) and stool-based prevalence was 1·8% (1·2-2·6%; 98%). Migrants from east Asia and the Pacific (17·3% [95% CI 4·1-37·0]), sub-Saharan Africa (14·6% [7·1-24·2]), and Latin America and the Caribbean (11·4% [7·8-15·7]) had the highest seroprevalence. Pooled schistosomiasis seroprevalence was 18·4% (95% CI 13·1-24·5; I2 97%) and stool-based prevalence was 0·9% (0·2-1·9; 99%). Sub-Saharan African migrants had the highest seroprevalence (24·1·% [95% CI 16·4-32·7]). Strongyloidiasis affects migrants from all global regions, whereas schistosomiasis is focused in specific regions and most common among sub-Saharan African migrants. Serological prevalence estimates were several times higher than stool estimates for both parasites. These data can be used to inform screening decisions for migrants and support the use of serological screening, which is more sensitive and easier than stool testing. None.