Role of nucleic acid amplification assays in monitoring treatment response in chagas disease: Usefulness in clinical trials

Chagas disease has become a global health problem due to migration of infected people out of Latin America to non-endemic countries. For more than 40 years, only the nitroimidazole compounds Benznidazole and Nifurtimox, have been used for specific treatment of Trypanosoma cruzi infection with disappointing results, specially due to the long duration of treatment and adverse events in the chronic phase. In the last years, ergosterol inhibitors have been also proposed for specific treatment. Different randomized clinical trials were performed for evaluating their treatment efficacy and safety. One of the greatest concerns in clinical trials is to provide an early surrogate biomarker of response to trypanocidal chemotherapy. Serological response is slow and the classical parasitological tests have poor sensitivity and are time-consuming. Nowadays, PCR is the most helpful tool for assessing treatment response in a short period of time. Different protocols of PCR have been developed, being quantitative real time PCR based on amplification of repetitive satellite or minicircle DNA sequences plus an internal amplification standard, the mostly employed strategies in clinical trials. Standardized protocols and the use of an external quality assessment ensure adequate technical procedures and reliable data. Clinical trials have shown a significant reduction in parasite loads, reaching undetectable DNA levels in bloodstream after specific treatment, however events of treatment failure have also been reported. Treatment failure could be due to inadequate penetrance of the drugs into the affected tissues, to the presence of primary or secondary drug resistance of the infecting strains as well as to the existence of dormant parasite variants reluctant to drug action. The early diagnosis of drug resistance would improve clinical management of Chagas disease patients, allowing dictating alternative therapies with a combination of existing drugs or new anti-T. cruzi agents. The aim of this review was to describe the usefulness of detecting T.cruzi DNA by means of real time PCR assays, as surrogate biomarker in clinical trials for evaluating new drugs for CD or new regimens of available drugs and the possibility to detect treatment failure.Fil: Sulleiro Igual, Elena. Universidad Autónoma de Barcelona. Hospital Vall D' Hebron; EspañaFil: Muñoz Calderon, Arturo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Schijman, Alejandro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin

Profilaxi de la malària en viatgers

Profilaxi de malària; Medicina del viatger; AntipalúdicsProfilaxis de malaria; Medicina del viajero; antipalúdicosMalaria prophylaxis; Traveler medicine; AntimalarialsLa malària representa la primera causa infecciosa de risc de complicacions greus i mort en viatgers internacionals. En el nostre àmbit, la majoria de casos de malària en viatgers correspon a persones que no han realitzat una quimiopro!laxi adequada i/o les estratègies per evitar la picada de mosquits no han funcionat. El col·lectiu més afectat són els immigrants que es desplacen temporalment als seus països d’origen per visitar familiars i amics, per la qual cosa cal insistir, especialment en aquest grup, a adoptar mesures de prevenció especí!ques. És molt important que les persones que han de viatjar a àrees de paludisme endèmic facin una consulta mèdica entre 4-8 setmanes prèvies al viatge. En aquesta consulta, es valorarà el risc de contraure malària i s’assessorarà segons cada cas, tenint en compte les característiques personals, l’itinerari, la durada i el tipus de viatge. Es donaran indicacions sobre les mesures de protecció personal: repel·lents, roba especí!ca i ús de mosquiteres, entre d’altres. També caldrà valorar la indicació de quimiopro!laxi amb fàrmacs. Actualment, els fàrmacs disponibles en el nostre àmbit són atovaquona/proguanil, me"oquina, doxiciclina i cloroquina. A més, s’hauran de tenir en compte situacions especials com l’embaràs i/o la immunosupressió

Approach to amoebic colitis: Epidemiological, clinical and diagnostic considerations in a non-endemic context (Barcelona, 2007-2017)

Amoebic colitis; Non-endemic; BarcelonaColitis amèbica; No-endèmic; BarcelonaColitis Amebiana; No-endémico; BarcelonaBACKGROUND: Amoebic colitis is the most frequent clinical manifestation of invasive intestinal infection due to Entamoeba histolytica and a common cause of diarrhoea worldwide. Since higher transmission rates are usually related to poor health and exposure to unhygienic conditions, cases reported in Europe usually involve immigrants and international travellers. The goal of this study was to characterise both the clinical and the epidemiological features of a European population diagnosed with amoebic colitis and then to evaluate the diagnostic tools and therapeutic options applied. METHODS AND RESULTS: This was a retrospective observational study in which data from all patients diagnosed with amoebic colitis attending at the International Health Units of two tertiary referral hospitals, Germans Trias i Pujol University Hospital (Badalona, North Barcelona Metropolitan Area) and Vall d'Hebron University Hospital (Barcelona city) between 2007 and 2017 were analysed. During the study period 50 patients were diagnosed with amoebic colitis. Thirty-six (72%) were men, and immigrants accounted for 46% of all cases. Antecedents of any international travel were reported for 28 (56%), the most frequent destinations having been the Indian subcontinent, South and Central America and sub-Saharan Africa. Preexisting pathological conditions or any kind of immunosuppression were identified in 29 (58%) patients; of these, 13 (26%) had HIV infection-all of them men who have sex with men-and 5 (10%) had inflammatory bowel disease. Diarrhoea, abdominal pain and dysentery were the most frequently recorded symptoms of invasive amoebae. Diagnosis was made through microbiological study in 45 (90%) and/or histological identification of amoebae in colon biopsies in 10 (20%). After treatment with metronidazole (82%) or tinidazole (8%), all patients had good outcomes. Post-acute intraluminal treatment was indicated in 28 (56%). CONCLUSIONS: Amoebic colitis should be suspected in patients with diarrhoea and compatible epidemiological risk factors (immigration, travelling abroad or men who have sex with men), especially if some degree of immunosuppression concurs. These risk factors must be taken into account in any diagnostic approach to inflammatory bowel disease (IBD), and active searches for stool parasites should be performed in such cases to rule out misdiagnosis or simultaneous amoebic infection. Treatment should include intraluminal anti-amoebic treatment in order to avoid relapse and prevent further spread of the disease

Sentinel surveillance of imported dengue via travellers to Europe 2012 to 2014: TropNet data from the DengueTools Research Initiative

Dengue; Vigilància; ImportacióDengue; Vigilancia; ImportaciónDengue; Surveillance; ImportationWe describe the epidemiological pattern and genetic characteristics of 242 acute dengue infections imported to Europe by returning travellers from 2012 to 2014. The overall geographical pattern of imported dengue (South-east Asia > Americas > western Pacific region > Africa) remained stable compared with 1999 to 2010. We isolated the majority of dengue virus genotypes and epidemic lineages causing outbreaks and epidemics in Asia, America and Africa during the study period. Travellers acted as sentinels for four unusual dengue outbreaks (Madeira, 2012–13; Luanda, 2013; Dar es Salaam, 2014; Tokyo, 2014). We were able to characterise dengue viruses imported from regions where currently no virological surveillance data are available. Up to 36% of travellers infected with dengue while travelling returned during the acute phase of the infection (up to 7 days after symptom onset) or became symptomatic after returning to Europe, and 58% of the patients with acute dengue infection were viraemic when seeking medical care. Epidemiological and virological data from dengue-infected international travellers can add an important layer to global surveillance efforts. A considerable number of dengue-infected travellers are viraemic after arrival back home, which poses a risk for dengue introduction and autochthonous transmission in European regions where suitable mosquito vectors are prevalent

Epidemiology of congenital Chagas disease 6 years after implementation of a public health surveillance system, Catalonia, 2010 to 2015

Chagas disease; Trypanosoma cruzi; CongenitalMalaltia de Chagas; Trypanosoma cruzi; CongènitEnfermedad de Chagas; Trypanosoma cruzi; CongénitoBackgroundChagas disease is endemic in Latin America and affects 8 million people worldwide. In 2010, Catalonia introduced systematic public health surveillance to detect and treat congenital Chagas disease.AimThe objective was to evaluate the health outcomes of the congenital Chagas disease screening programme during the first 6 years (2010-2015) after its introduction in Catalonia.MethodsIn a surveillance system, we screened pregnant women and newborns and other children of positive mothers, and treated Chagas-positive newborns and children. Diagnosis was confirmed for pregnant women and children with two positive serological tests and for newborns with microhaematocrit and/or PCR at birth or serology at age 9 months.ResultsFrom 2010 to 2015, the estimated screening coverage rate increased from 68.4% to 88.6%. In this period, 33,469 pregnant women were tested for Trypanosoma cruzi and 937 positive cases were diagnosed. The overall prevalence was 2.8 cases per 100 pregnancies per year (15.8 in Bolivian women). We followed 82.8% of newborns until serological testing at age 9-12 months and 28 were diagnosed with Chagas disease (congenital transmission rate: 4.17%). Of 518 siblings, 178 (34.3%) were tested and 14 (7.8%) were positive for T. cruzi. Having other children with Chagas disease and the heart clinical form of Chagas disease were maternal risk factors associated with congenital T. cruzi infection (p < 0.05).ConclusionThe increased screening coverage rate indicates consolidation of the programme in Catalonia. The rate of Chagas disease congenital transmission in Catalonia is in accordance with the range in non-endemic countries

A retrospective study on the influence of siblings' relatedness in Bolivian patients with chronic Chagas disease

Brotherhood; Cardiomyopathy; Chagas diseaseGermandat; Cardiomiopatia; Malaltia de chagasHermandad; Cardiomiopatía; Enfermedad de chagasBACKGROUND: Chagas disease is a protozoan infection caused by Trypanosoma cruzi. The disease has a chronic course in which 20-30% of the patients would develop progressive damage to the cardiovascular system and the gastrointestinal tube. We are still unable to predict who will develop end-organ damage but there are some acquired and genetic risk factors already known. RESULTS: We reviewed data from 833 patients with serologically confirmed Chagas disease in this retrospective study. Patients were classified as siblings or non-siblings (controls) and the results of pre-treatment blood PCR assay, end-organ damage (cardiac and/or gastrointestinal), and the presence of delayed type hypersensitivity (DTH) skin involvement in patients treated with benznidazole were analyzed. Siblings were grouped by family and we randomly generated groups of 2 or 3 persons with the remaining controls. We classified the results of each variable as concordant or discordant and compared the concordance in these results among the sibling groups with that among control groups. We identified 71 groups of siblings and randomly generated 299 groups of non-related patients. Pre-treatment blood PCR concordance was significantly higher (19%) among siblings compared to controls (P = 0.02), probably due to a higher frequency in pre-treatment positive results. No other statistically significant differences were found. CONCLUSIONS: A significant difference was found in the concordance of pre-treatment blood PCR for T. cruzi among siblings compared to non-related controls

Immune reactivity to Trypanosoma cruzi chimeric proteins for Chagas disease diagnosis in immigrants living in a non-endemic setting

Chagas disease; Chimeric antigens; Trypanosoma cruziMalaltia de Chagas; Antígens quimèrics; Trypanosoma cruziEnfermedad de Chagas; Antígenos quiméricos; Trypanosoma cruziBACKGROUND: Chronic Chagas Disease (CD) diagnosis is based on serological methods employing crude, semipurified or recombinant antigens, which may result in low sensitivity or cross-reactivity. To reduce these restrictions, we developed a strategy involving use of molecules containing repetitive fragments of Trypanosoma cruzi conserved proteins. Diagnostic performance of IBMP-8.1 and IBMP-8.4 chimeric antigens (Molecular Biology Institute of Paraná - IBMP in Portuguese acronym) was assessed to diagnose T. cruzi-infected and non-infected immigrants living in Barcelona (Spain), a non-endemic setting for Chagas disease. METHODS: Reactivity of IBMP-8.1 and IBMP-8.4 was assessed using an in-house automated ELISA with 347 positive and 331 negative individuals to Chagas disease. Antigenic cross-reactivity was measured with sera samples from pregnant women with Toxoplasma gondii (n = 98) and Zika virus (n = 75) antibodies. RESULTS: The area under the curve values was 1 and 0.99 for the IBMP-8.1 and IBMP-8.4 proteins, respectively, demonstrating excellent diagnostic accuracy. The reactivity index was higher for IBMP-8.1 than IBMP-8.4 in positive samples and no significant difference in reactivity index was observed in negative samples. Sensitivity ranged from 99.4% for IBMP-8.1 to 99.1% for IBMP-8.4 and was not statistically different. Specificity for IBMP-8.1 reached 100 and 99.7% for IBMP-8.4, both nearly 100% accurate. No antigenic cross-reactivity was observed and reactivity index was similar to that for negative Chagas disease individuals. CONCLUSIONS: Our results showed an outstanding performance of IBMP-8.1 and IBMP-8.4 chimeric antigens by ELISA and suggest both chimeric antigens could also be used for Chagas disease diagnosis in immigrants living in non-endemic settings

Human Trypanosoma cruzi chronic infection leads to individual level steady-state parasitemia: Implications for drug-trial optimization in Chagas disease

Parasitemia; Parasitic diseases; Bloodstream infectionsParasitemia; Enfermedades parasitarias; Infecciones del torrente sanguíneoParasitèmia; Malalties parasitàries; Infeccions del torrent sanguiniCurrently available drugs against Trypanosoma cruzi infection, which causes 12000 deaths annually, have limitations in their efficacy, safety and tolerability. The evaluation of therapeutic responses to available and new compounds is based on parasite detection in the bloodstream but remains challenging because a substantial proportion of infected individuals have undetectable parasitemia even when using diagnostic tools with the highest accuracy. We characterize parasite dynamics which might impact drug efficacy assessments in chronic Chagas by analyzing pre- and post-treatment quantitative-PCR data obtained from blood samples collected regularly over a year. We show that parasitemia remains at a steady-state independently of the diagnostic sensitivity. This steady-state can be probabilistically quantified and robustly predicted at an individual level. Furthermore, individuals can be assigned to categories with distinct parasitological status, allowing a more detailed evaluation of the efficacy outcomes and adjustment for potential biases. Our analysis improves understanding of parasite dynamics and provides a novel background for optimizing future drug efficacy trials in Chagas disease

Risk of Trypanosoma cruzi infection among travellers visiting friends and relatives to continental Latin America

Factors de risc mèdic; Serologia; Malaltia de ChagasFactores de riesgo médicos; Serología; Enfermedad de ChagasMedical risk factors; Serology; Chagas diseaseBackground Chagas disease (CD) is regarded as a possible risk for travellers to endemic areas of continental Latin America (LA). The aim of the study is to determine the risk of Trypanosoma cruzi (TC) infection among travellers to CD endemic areas and to identify risk factors for acquiring TC infection. Methods/Principal finding We designed a multicenter cross-sectional study among travellers in Spain (Badalona, Barcelona and Madrid). All available adults with laboratory confirmed proof of absence of TC infection from January 2012 to December 2015 were contacted. Participants referring a trip to LA after the negative TC screening were offered to participate. We performed a standardized questionnaire of travel related factors and measurement of TC antibodies in serum. A total of 971 participants with baseline negative TC serology were selected from the microbiology records. After excluding participants not meeting inclusion criteria, eighty participants were selected. Sixty three (78.8%) were female, and the median age was 38 (IQR 34–47) years. The reason to travel was visiting friends and relatives in 98.8% of the participants. The median duration of travel was 40 (IQR 30–60) days, with 4911 participants-day of exposure. Seventy seven cases (96.25%) participants had two negative TC serology tests after the travel, two cases (2.5%) had discordant serology results (considered false positive results) and one case was infected before travelling to LA. According to our data, the upper limit of the 95% confidence interval of the incidence rate of TC acquisition in travellers is 0.8 per 1000 participant-days. Conclusions/Significance Among 79 non-CD travellers to TC endemic areas, we found no cases of newly acquired TC infection. The incidence rate of TC acquisition in travellers to endemic countries is less than or equal to 0.8 per 1000 traveller-days.ASM was supported by a postdoctoral grant “Juan Rodés” (JE18/00022) from the Instituto de Salud Carlos III (www.isciii.es) through the Spanish Ministry of economy and competitiveness. The funders had no role in study design data collection and analysis, decision to publish, or preparation of the manuscript

Advances and challenges in automated malaria diagnosis using digital microscopy imaging with artificial intelligence tools: A review

Deep learning; Malaria diagnosis; Microscopic examinationAprenentatge profund; Diagnòstic de malària; Examen microscòpicAprendizaje profundo; Diagnóstico de malaria; Examen microscópicoMalaria is an infectious disease caused by parasites of the genus Plasmodium spp. It is transmitted to humans by the bite of an infected female Anopheles mosquito. It is the most common disease in resource-poor settings, with 241 million malaria cases reported in 2020 according to the World Health Organization. Optical microscopy examination of blood smears is the gold standard technique for malaria diagnosis; however, it is a time-consuming method and a well-trained microscopist is needed to perform the microbiological diagnosis. New techniques based on digital imaging analysis by deep learning and artificial intelligence methods are a challenging alternative tool for the diagnosis of infectious diseases. In particular, systems based on Convolutional Neural Networks for image detection of the malaria parasites emulate the microscopy visualization of an expert. Microscope automation provides a fast and low-cost diagnosis, requiring less supervision. Smartphones are a suitable option for microscopic diagnosis, allowing image capture and software identification of parasites. In addition, image analysis techniques could be a fast and optimal solution for the diagnosis of malaria, tuberculosis, or Neglected Tropical Diseases in endemic areas with low resources. The implementation of automated diagnosis by using smartphone applications and new digital imaging technologies in low-income areas is a challenge to achieve. Moreover, automating the movement of the microscope slide and image autofocusing of the samples by hardware implementation would systemize the procedure. These new diagnostic tools would join the global effort to fight against pandemic malaria and other infectious and poverty-related diseases.The project is funded by the Microbiology Department of Vall d’Hebron Universitary Hospital, the Cooperation Centre of the Universitat Politècnica de Catalunya (CCD-UPC) and the Probitas Foundation