Evaluation of Loop-Mediated Isothermal Amplification (LAMP) in Urine Samples for the Diagnosis of Imported Schistosomiasis.

Migratory flows and international travel are triggering an increase in imported cases of schistosomiasis in non-endemic countries. The present study aims to evaluate the effectiveness of the LAMP technique on patients' urine samples for the diagnosis of imported schistosomiasis in a non-endemic area in comparison to a commercial immunochromatographic test and microscopic examination of feces and urine. A prospective observational study was conducted in sub-Saharan migrants attending the Tropical Medicine Unit, Almería, Spain. For schistosomiasis diagnosis, serum samples were tested using an immunochromatographic test (Schistosoma ICT IgG-IgM). Stool and urine samples were examined by microcopy. Urine samples were evaluated by combining three LAMP assays for the specific detection of Schistosoma mansoni, S. haematobium, and for the genus Schistosoma. To evaluate the diagnostic accuracy, a latent class analysis (LCA) was performed. In total, 115 patients were included (92.2% male; median age: 28.3 years). Of these, 21 patients (18.3%) were diagnosed with schistosomiasis confirmed by microscopy, with S. haematobium being the most frequent species identified (18/115; 15.7%). The Schistosoma ICT IgG-IgM test result was 100% positive and Schistosoma-LAMP was 61.9% positive, reaching as high as 72.2% for S. haematobium. The sensitivity and specificity estimated by LCA, respectively, were: 92% and 76% for Schistosoma ICT IgG-IgM, 68% and 44% for Schistosoma-LAMP, and 46% and 97% for microscopy. In conclusion, the Schistosoma-LAMP technique presented a higher sensitivity than microscopy for the diagnosis of imported urinary schistosomiasis, which could improve the diagnosis of active infection, both in referral centers and in centers with limited experience or scarce resources and infrastructure.

Estimation of parasitaemia in imported falciparum malaria using the results of a combined rapid diagnostic test. No big help from haematological parameters.

BACKGROUND: Microscopy continues to be the mainstay for the evaluation of parasitaemia in malaria but requires laboratory support and microbiological experience. Other fast and simple methods are necessary. METHODS: A retrospective observational study of imported malaria treated from July-2007 to December-2020 was carried out to evaluate the association between the degree of parasitaemia and both rapid diagnostic tests (RDT) reactivity patterns and haematological parameters. Plasmodium falciparum monoinfections diagnosed by peripheral blood smear and/or polymerase chain reaction (PCR),which also had a positive RDT result in the same blood sample, were included in the study. RESULTS: A total of 273 patients were included. Most of them were male (n = 256; 93.8%) and visiting friends and relatives (VFR) travellers (n = 252; 92.3%). Patients with plasmodial lactate dehydrogenase (pLDH) or aldolase and histidine-rich protein 2 (HRP-2) co-reactivity (Pan/Pf pattern) had a parasitaemia range between 0 and 37% while those with just HRP-2 reactivity (P. falciparum pattern) had ranges between 0 and 1%. Not a single case of P. falciparum pattern was found for parasitaemia ranges greater than 1%, showing a negative predictive value of 100% for high parasitaemia. All the correlations between haematological parameters and parasitaemia resulted to be weak, with a maximum rho coefficient of -0.35 for lymphocytes and platelets, and of 0.40 for neutrophils-to-lymphocytes count ratio. Multivariate predictive models were constructed reflecting a poor predictive capacity. CONCLUSIONS: The reactivity pattern of RDT allows a rapid semi-quantitative assessment of P. falciparum parasitaemia in travellers with imported malaria, discriminating patients with lower parasite loads. Haematological parameters were not able to estimate parasitaemia with sufficient precision.

Geographical Influence on Morphometric Variability of Genetically "Pure" Schistosoma haematobium Eggs from Sub-Saharan Migrants in Spain.

Schistosome eggs play a key role in schistosomiasis diagnosis and research. The aim of this work is to morphogenetically study the eggs of Schistosoma haematobium found in sub-Saharan migrants present in Spain, analyzing their morphometric variation in relation to the geographical origin of the parasite (Mali, Mauritania and Senegal). Only eggs considered "pure" S. haematobium by genetic characterization (rDNA ITS-2 and mtDNA cox1) have been used. A total of 162 eggs obtained from 20 migrants from Mali, Mauritania and Senegal were included in the study. Analyses were made by the Computer Image Analysis System (CIAS). Following a previously standardized methodology, seventeen measurements were carried out on each egg. The morphometric analysis of the three morphotypes detected (round, elongated and spindle) and the biometric variations in relation to the country of origin of the parasite on the egg phenotype were carried out by canonical variate analysis. Mahalanobis distances, when all egg measurements were analyzed, showed differences between: (i) Mali-Mauritania, Mali-Senegal and Mauritania-Senegal in the round morphotype; (ii) Mali-Mauritania and Mauritania-Senegal in the elongated morphotype; and (iii) Mauritania-Senegal in the spindle morphotype. Mahalanobis distances, when spine variables were analyzed, showed differences between Mali-Senegal in the round morphotype. In conclusion, this is the first phenotypic study performed on individually genotyped "pure" S. haematobium eggs, allowing the assessment of the intraspecific morphological variations associated with the geographical origin of the schistosome eggs.

Accuracy of Three Serological Techniques for the Diagnosis of Imported Schistosomiasis in Real Clinical Practice: Not All in the Same Boat.

Schistosomiasis is a neglected tropical disease despite of being a major public health problem affecting nearly 240 million people in the world. Due to the migratory flow from endemic countries to Western countries, an increasing number of cases is being diagnosed in non-endemic areas, generally in migrants or people visiting these areas. Serology is the recommended method for screening and diagnosis of schistosomiasis in migrants from endemic regions. However, serological techniques have a highly variable sensitivity. The aim of this study was to evaluate retrospectively the sensitivity of three different serological tests used in real clinical practice for the screening and diagnosis of imported schistosomiasis in sub-Saharan migrant patients, using the detection of schistosome eggs in urine, faeces or tissues as the gold standard. We evaluated three different serological techniques in 405 sub-Saharan patients with confirmed schistosomiasis treated between 2004 and 2022: an enzyme-linked immunosorbent assay (ELISA), an indirect haemagglutination assay (IHA) and an immunochromatographic test (ICT). The overall sensitivity values obtained with the different techniques were: 44.4% for IHA, 71.2% for ELISA and 94.7% for ICT, respectively. According to species, ICT showed the highest sensitivity (S. haematobium: 94%, S. mansoni: 93.3%; and S. intercalatum/guineensis: 100%). In conclusion, our study shows that Schistosoma ICT has the best performance in real clinical practice, when compared to ELISA and IHA, in both S. mansoni and S. haematobium infections.

Misleading eosinophil counts in migration-associated malaria: do not miss hidden helminthic co-infections.

BACKGROUND: Lower eosinophil counts observed during acute malaria episodes could hide helminth-related eosinophilia. METHOD: Retrospective observational study with sub-Saharan migrants with imported malaria from May-2007 to May-2020. Absolute eosinophil count was determined upon diagnosis at hospital admission and at least once after clearance of parasitemia. Helminthic co-infections were investigated by searching for stool and urine parasites, serology for Strongyloides spp. and Schistosoma spp., and Knott and/or saponin tests for blood microfilariae. RESULTS: A total of 259 patients were included. Most of them were male (n = 237; 91.5%) and VFR travelers (n = 241; 93.1%). 131 patients (50.6%) were diagnosed with probable schistosomiasis, 15 (5.8%) with confirmed schistosomiasis, 16 (6.2%) with strongyloidiasis, 4 (1.6%) with soil-transmitted helminthiasis, and 4 (1.6%) with filariasis (Mansonella perstans). Prevalence of eosinophilia increased from 2.7% on admission to 32.5% during outpatient follow-up. Eosinophilia did not appear until several weeks after hospital discharge in up to 24% of the confirmed helminthic co-infections and in 61.1% of patients with probable schistosomiasis. Eosinophilia was associated with confirmed schistosomiasis and mansonellosis while 56.2% and 75% of cases with strongyloidiasis and soil-transmitted worms did not present eosinophilia at any time, respectively. CONCLUSIONS: Regardless of the absence of eosinophilia, patients hospitalized because of acute imported malaria might benefit from the screening of the main parasitic diseases, allowing for earlier diagnosis and treatment.

Migration-associated malaria from Africa in southern Spain.

BACKGROUND: The western area of the province of Almeria, sited in southern Spain, has one of the highest immigrant population rates in Spain, mainly dedicated to agricultural work. In recent years, there has been a significant increase in the number of cases of imported malaria associated with migrants from countries belonging to sub-Saharan Africa. The objective of our study is to describe the epidemiological, clinical and analytical characteristics of malaria patients treated in a specialized tropical unit, paying special attention to the differences between VFR and non-VFR migrants and also to the peculiarities of microscopic malaria cases compared to submicroscopic ones. METHODS: Retrospective observational study of migrants over 14 years of age with imported malaria treated from October 2004 to May 2019. Characteristics of VFR and non-VFR migrants were compared. Malaria cases were divided into microscopic malaria (MM) and submicroscopic malaria (SMM). SMM was defined as the presence of a positive malaria PCR test together with a negative direct microscopic examination and a negative rapid diagnostic test (RDT). Microscopic malaria was defined as the presence of a positive RDT and/or a positive smear examination. RESULTS: Three hundred thirty-six cases of malaria were diagnosed, 329 in sub-Saharan immigrants. Of these, 78.1% were VFR migrants, in whom MM predominated (85.2% of cases). In non-VFR migrants, SMM represented 72.2% of the cases. Overall, 239 (72.6%) patients presented MM and 90 (27.4%) SMM. Fever was the most frequent clinical manifestation (64.4%), mainly in the MM group (MM: 81.1% vs SMM: 20.0%; p < 0.01). The most frequent species was P. falciparum. Patients with SMM presented fewer cytopenias and a greater number of coinfections due to soil-transmitted helminths, filarial and intestinal protozoa compared to patients with MM. CONCLUSIONS: Imported malaria in our area is closely related to sub-Saharan migration. VFR migrants are the main risk group, highlighting the need for actions aimed at improving disease prevention measures. On the other hand, almost a third of the cases are due to SMM. This fact could justify its systematic screening, at least for those travelers at greater risk.

Uso directo de identificación cromogénica y antibiograma directo (E-test) sobre muestra clínica para la identificación y estudio de sensibilidad de uropatógenos / Direct use of chromogenic identification and antibiogram (E-test) on clinical samples in order to perform identification and susceptibility tests on urinary pathogens

La obtención rápida y asequible de resultados es prioritaria. Para ello propusimos la realización de identificación y antibiograma sobre muestras de orina directa, mediante placa cromogénica CPS® y E-test (BioMérieux, Francia). Se evaluó la concordancia con los procedimientos standard, estableciendo un protocolo paralelo a la rutina haciendo lecturas de identificación y antibiograma a las 6 y 24 horas sobre 54 muestras clínicas de orina. La identificación concordó en un 88,88% a las 6 horas y en un 100% a las 24. El antibiograma solo detectó errores menores en amoxicilina-clavulánico y cefuroxima en la lectura a las 6 horas. Concluimos que en el caso de infecciones urinarias causadas por bacilos Gram negativos no Pseudomonas spp. la lectura a las 6 h del E-test sobre muestra directa es muy fiable como antibiograma presuntivo y para la detección de BLEE (AU)

Getting fast and affordable laboratory results is a priority. A method for the direct identification and susceptibility testing on direct urine samples by chromogenic plate CPS ® and E-test (BioMérieux, France) is presented. Tests were performed in parallel in order to compare the direct identification and susceptibility results at 6 h and 24 h on 54 samples of urine with the standard procedure. Identification agreement was 88.88% (6 h) and 100% (24 h). Antimicrobial susceptibility testing detected only minor errors in amoxicillin-clavulanate and cefuroxime (6 h). It is concluded that six hours testing is a very reliable susceptibility and extended-spectrum beta-lactamase (ESBL) detection method for urinary tract infection caused by non-Pseudomonas spp Gram negative bacteria (AU)