Model Based System Engineering (MBSE) and design assurance process in the context of mitigation of design errors during the development of highly integrated and complex aerospace systems.

Over the years, aircraft and spacecraft designs incorporated highly integrated and/or complex systems that can manage complex scenarios during its operation. In addition to the inherent complexity and/or high level of integration of those systems, the development process applied to aerospace programs is also challenged by other factors: program schedule, budget, multidisciplinary teams, new industry emerging technologies, large number of different processes and procedures that guide the activities along the development life cycle, and others. Given the fact many tasks executed during the development of such systems require human interaction, that yields the introduction of design errors that can contribute to the occurrence of non-desired system behaviors during operation phase. It is already recognized by the civil aviation industry that it is unfeasible to have a deterministic test set to demonstrate that such systems are completely free of such design errors. In that context, a huge effort is applied by the industry, by using qualitative methods to mitigate the occurrence of design errors during the development phases. This paper discusses how MBSE methodology applied together with a design assurance process could prevent such design errors, and presents an analysis showing how some events in aerospace industry where a design error was one of the contributing factors could be avoided.

Serology for visceral leishmaniasis: How trusty is the accuracy reported by the manufacturers?

Timely and accurate diagnosis is one of the strategies for managing visceral leishmaniasis (VL). Given the specificities of this infection, which affects different vulnerable populations, the local assessment of the accuracy of the available diagnostic test is a requirement for the good use of resources. In Brazil, performance data are required for test registration with the National Regulatory Agency (ANVISA), but there are no minimum requirements established for performance evaluation. Here, we compared the accuracy reported in the manufacturer's instructions of commercially available VL-diagnostic tests in Brazil, and the accuracies reported in the scientific literature which were obtained after test commercialization. The tests were identified via the electronic database of ANVISA, and their accuracy was obtained from the manufacturer's instructions. A literature search for test accuracy was performed using two databases. A total of 28 VL diagnostic tests were identified through the ANVISA database. However, only 13 presented performance data in the manufacturer's instructions, with five immunoenzymatic tests, three indirect immunofluorescence tests, one chemiluminescence test, and four rapid tests. For most tests, the manufacturers did not provide the relevant information, such as sample size, reference standards, and study site. The literature review identified accuracy data for only 61.5% of diagnostic tests registered in Brazil. These observations confirmed that there are significant flaws in the process of registering health technologies and highlighted one of the reasons for the insufficient control of policies, namely, the use of potentially inaccurate and inappropriate diagnostic tools for a given scenario.

Serology for visceral leishmaniasis: How trusty is the accuracy reported by the manufacturers?

ABSTRACT Timely and accurate diagnosis is one of the strategies for managing visceral leishmaniasis (VL). Given the specificities of this infection, which affects different vulnerable populations, the local assessment of the accuracy of the available diagnostic test is a requirement for the good use of resources. In Brazil, performance data are required for test registration with the National Regulatory Agency (ANVISA), but there are no minimum requirements established for performance evaluation. Here, we compared the accuracy reported in the manufacturer's instructions of commercially available VL-diagnostic tests in Brazil, and the accuracies reported in the scientific literature which were obtained after test commercialization. The tests were identified via the electronic database of ANVISA, and their accuracy was obtained from the manufacturer's instructions. A literature search for test accuracy was performed using two databases. A total of 28 VL diagnostic tests were identified through the ANVISA database. However, only 13 presented performance data in the manufacturer's instructions, with five immunoenzymatic tests, three indirect immunofluorescence tests, one chemiluminescence test, and four rapid tests. For most tests, the manufacturers did not provide the relevant information, such as sample size, reference standards, and study site. The literature review identified accuracy data for only 61.5% of diagnostic tests registered in Brazil. These observations confirmed that there are significant flaws in the process of registering health technologies and highlighted one of the reasons for the insufficient control of policies, namely, the use of potentially inaccurate and inappropriate diagnostic tools for a given scenario.

Performance differences among commercially available antigen rapid tests for COVID-19 in Brazil.

A rapid and accurate diagnosis is a crucial strategy for containing the coronavirus disease (COVID-19) pandemic. Considering the obstacles to upscaling the use of RT-qPCR, rapid tests based on antigen detection (Ag-RDT) have become an alternative to enhance mass testing, reducing the time for a prompt diagnosis and virus spreading. However, the performances of several commercially available Ag-RDTs have not yet been evaluated in several countries. Here, we evaluate the performance of eight Ag-RDTs available in Brazil to diagnose COVID-19. Patients admitted to tertiary hospitals with moderate or mild COVID-19 symptoms and presenting risk factors for severe disease were included. The tests were performed using a masked protocol, strictly following the manufacturer's recommendations and were compared with RT-qPCR. The overall sensitivity of the tests ranged from 9.8 to 81.1%, and specificity greater than 83% was observed for all the evaluated tests. Overall, slight or fair agreement was observed between Ag-RDTs and RT-PCR, except for the Ag-RDT COVID-19 (Acro Biotech), in which moderate agreement was observed. Lower sensitivity of Ag-RDTs was observed for patients with cycle threshold > 25, indicating that the sensitivity was directly affected by viral load, whereas the effect of the disease duration was unclear. Despite the lower sensitivity of Ag-RDTs compared with RT-qPCR, its easy fulfillment and promptness still justify its use, even at hospital admission. However, the main advantage of Ag-RDTs seems to be the possibility of increasing access to the diagnosis of COVID-19 in patients with a high viral load, allowing immediate clinical management and reduction of infectivity and community transmission.

Cost-effectiveness of anti-SARS-CoV-2 antibody diagnostic tests in Brazil.

BACKGROUND: Although serologic tests for COVID-19 diagnosis are rarely indicated nowadays, they remain commercially available and widely used in Brazil. The objective of this study was to evaluate the cost-effectiveness of anti-SARS-CoV-2antibody diagnostic tests for COVID-19 in Brazil. METHODS: Eleven commercially available diagnostic tests, comprising five lateral-flow immunochromatographic assays (LFAs) and six immunoenzymatic assays (ELISA) were analyzed from the perspective of the Brazilian Unified Health System. RESULTS: The direct costs of LFAs ranged from US$ 11.42 to US$ 17.41and of ELISAs, from US$ 6.59 to US$ 10.31. Considering an estimated disease prevalence between 5% and 10%, the anti-SARS-CoV-2 ELISA (IgG) was the most cost-effective test, followed by the rapid One Step COVID-19 Test, at an incremental cost-effectiveness ratio of US$ 2.52 and US$ 1.26 per properly diagnosed case, respectively. Considering only the LFAs, at the same prevalence estimates, two tests, the COVID-19 IgG/IgM and the One Step COVID-19 Test, showed high effectiveness at similar costs. For situations where the estimated probability of disease is 50%, the LFAs are more costly and less effective alternatives. CONCLUSIONS: Nowadays there are few indications for the use of serologic tests in the diagnosis of COVID-19 and numerous commercially available tests, with marked differences are observed among them. In general, LFA tests are more cost-effective for estimated low-COVID-19-prevalences, while ELISAs are more cost-effective for high-pretest-probability scenarios.

Economic evaluations addressing diagnosis and treatment strategies for neglected tropical diseases: an overview.

Neglected tropical diseases (NTDs) are those affecting vulnerable people and causing additional social and economic burden. The aim of this study was to carry out a general overview of the health economic assessments involving the diagnosis and treatment of six NTDs: cutaneous leishmaniasis (CL), Chagas disease, cysticercosis, filariasis, schistosomiasis and visceral leishmaniasis (VL). The literature search was based on two of the main medical literature databases (Medline and SciELO) and identified 46 studies. Twenty-six studies (57%) addressed therapeutic strategies, while other 20 (43%) assessed diagnostic or both diagnostic and therapeutic approaches. The studies were published between 1994 and 2021, and 57% of them (26/46) were carried out in four countries. Cost-effectiveness analyses were conducted in 59% (27/46) of the studies. Economic studies of NTDs have timidly increased in recent years. Despite the improvement of analytical methods, completeness and accuracy of information, there are few new technologies applied to NTDs and public health systems. In addition, economic studies for NTDs are concentrated in a few countries. Thus, this review points out the need for investment in research, development and training of human resources dedicated to the economic analysis in health, especially on NTDs, as a strategy to reduce inequalities by optimizing the use of health resources.

Diagnostic performance of commercially available COVID-19 serology tests in Brazil.

Timely and accurate laboratory testing is essential for managing the global COVID-19 pandemic. Reverse transcription polymerase chain reaction remains the gold-standard for SARS-CoV-2 diagnosis, but several practical issues limit the test's use. Immunoassays have been indicated as an alternative for individual and mass testing. OBJECTIVES: To access the performance of 12 serological tests for COVID-19 diagnosis. METHODS: We conducted a blind evaluation of six lateral-flow immunoassays (LFIAs) and six enzyme-linked immunosorbent assays (ELISAs) commercially available in Brazil for detecting anti-SARS-CoV-2 antibodies. RESULTS: Considering patients with seven or more days of symptoms, the sensitivity ranged from 59.5% to 83.1% for LFIAs and from 50.7% to 92.6% for ELISAs. For both methods, the sensitivity increased with clinical severity and days of symptoms. The agreement among LFIAs performed with digital blood and serum was moderate. Specificity was, in general, higher for LFIAs than for ELISAs. Infectious diseases prevalent in the tropics, such as HIV, leishmaniasis, arboviruses, and malaria, represent conditions with the potential to cause false-positive results with these tests, which significantly compromises their specificity. CONCLUSION: The performance of immunoassays was only moderate, affected by the duration and clinical severity of the disease. Absence of discriminatory power between IgM/IgA and IgG has also been demonstrated, which prevents the use of acute-phase antibodies for decisions on social isolation.

Cost-effectiveness of serological tests for human visceral leishmaniasis in the Brazilian scenario.

Human visceral leishmaniasis (VL) is a severe and potentially fatal parasitic disease if not correctly diagnosed and treated. Brazil is one of the three countries most endemic for VL and, like most countries affected by this disease, has a large budget constraint for the incorporation of new health technologies. Although different diagnostic tests for VL are currently available in the country, economic studies evaluating diagnostic kits are scarce. The objective of this study was to conduct a cost-effectiveness analysis of the nine available diagnostic tests for human VL in HIV-infected and uninfected patients in Brazil. The perspective of analysis was the Brazilian public health system, and the outcome of interest was "cases diagnosed correctly". The costs of the tests were estimated using the microcosting technique, and comparisons were performed with decision trees. Sensitivity analyses were explored applying variations in cost and effectiveness values. For VL diagnosis among HIV-uninfected patients, using blood samples for the rapid tests (RDTs), the noncommercial direct agglutination test (DAT-LPC) and IT-LEISH were cost-effective tests compared with the baseline OnSite test, but they presented different incremental cost-effectiveness ratios (ICER) of US$7.04 and US$ 205.40, respectively. Among HIV-infected patients, DAT-LPC was the most cost-effective diagnostic test. Comparisons among the tests with the same methodology, based on the low ICER values, revealed that IT-LEISH was the most cost-effective test among the RDTs and the Ridascreen Leishmania Ab among the ELISA tests. These results confirm that cost-effectiveness analyses can provide useful information to support the incorporation of new health technologies within a known scenario and willingness to pay threshold. It was observed that tests based on the same methodologies presented different cost-effectiveness ratios for the same group of patients and that different tests should be recommended for different patient groups. DAT-LPC was an important cost-effective strategy for all patients, requiring minimum laboratorial infrastructure, and IT-LEISH was the cost-effective test for VL screening in HIV-uninfected patients. IT-LEISH and DAT-LPC have complementary profiles and should both be provided by the Brazilian health system.

Economic impact of localized cutaneous leishmaniasis on adult patients of a referral service in Belo Horizonte, Minas Gerais State, Brazil.

Cutaneous leishmaniasis (CL) is a disease associated with low-income populations. Thus, in assessing the burden of this disease, it is important to include its economic impact on individuals. We aimed to evaluate CL economic impact on patients treated at a referral service in the State of Minas Gerais, Brazil. This is a cross-sectional study based on the analysis of interviews and medical records from which we assembled direct medical and non-medical costs related to CL, from a societal perspective. One hundred patients were included; 50% had a monthly per capita income of up to USD 259.60 and spent on average USD 187.32 with the disease, representing an average monthly impact of 22.5% (USD 133.80). The disease imposed direct medical costs, such as: private medical appointments, medications, medical exams, dressing material, and co-participation in health insurances. Direct non-medical costs were mainly related to patients' transportation to health centers (USD 4,911.00), but also included medically-necessary care, food, and domestic and business outsourcing services. Although the Brazilian public health system guarantees access to health care, CL still represents a substantial economic impact for patients. The main action to reduce the expenses with this disease is decentralizing services for CL diagnosis and therapeutic approach, as well as increasing their efficiency.

Impaired Thymic Output Can Be Related to the Low Immune Reconstitution and T Cell Repertoire Disturbances in Relapsing Visceral Leishmaniasis Associated HIV/AIDS Patients.

Background: Visceral leishmaniasis/HIV-co-infected patients (VL/HIV) accounts for around 8% of VL reported cases in Brazil. Relapses of Leishmania infection after anti-leishmanial treatment constitute a great challenge in the clinical practice because of the disease severity and drug resistance. We have shown that non-relapsing-VL/HIV (NR-) evolved with increase of CD4+ T-cell counts and reduction of activated CD4+ and CD8+ T cells after anti-leishmanial treatment. This immune profile was not observed in relapsing-VL/HIV patients (R-), indicating a more severe immunological compromising degree. Elevated activation status may be related to a deficient immune reconstitution and could help to explain the frequent relapses in VL/HIV co-infection. Our aim was to evaluate if this gain of T cells was related to changes in the peripheral TCRVß repertoire and inflammatory status, as well as the possible thymus involvement in the replenishment of these newly formed T lymphocytes. Methods: VL/HIV patients, grouped into non-relapsing (NR- = 6) and relapsing (R- = 12) were evaluated from the active phase up to 12 months post-treatment (mpt). HIV-infected patients (non-VL) and healthy subjects (HS) were included. The TCRVß repertoire was evaluated ex vivo by flow cytometry, whereas the plasmatic cytokine levels were assessed by Luminex assay. To evaluate the thymic output, DNA was extracted from PBMCs for TCR rearrangement excision circles (TREC) quantification by qPCR. Results: VL/HIV cases presented an altered mobilization profile (expansions or retractions) of the TCRVß families when compared to HS independent of the follow-up phase (p < 0.05). TCRVß repertoire on CD4+ T-cells was more homogeneous in the NR-VL/HIV cases, but heterogeneous on CD8+ T-cells, since different Vß-families were mobilized. NR-VL/HIV had the inflammatory pattern reduced after 6 mpt. Importantly, VL/HIV patients showed number of TREC copies lower than controls during all follow-up. An increase of recent thymic emigrants was observed in NR-VL/HIV individuals at 10 mpt compared to R- patients (p < 0.01), who maintained lower TREC contents than the HIV controls. Conclusions: VL/HIV patients that maintain the thymic function, thus generating new T-cells, seem able to replenish the T lymphocyte compartment with effector cells, then enabling parasite control.

A Real-Time PCR Assay for the Diagnosis of Intestinal Schistosomiasis and Cure Assessment After the Treatment of Individuals With Low Parasite Burden.

The laboratorial diagnosis of the intestinal schistosomiasis is always performed using Kato-Katz technique. However, this technique presents low sensitivity for diagnosis of individuals with low parasite burden, which constitutes the majority in low endemicity Brazilian locations for the disease. The objective of this study was developed and to validate a real-time PCR assay (qPCR) targeting 121 bp sequence to detect Schistosoma spp. DNA for the diagnosis of intestinal schistosomiasis and a sequence of the human ß-actin gene as internal control. Firstly, the qPCR was standardized and next it was evaluated for diagnosis and cure assessment of intestinal schistosomiasis in the resident individuals in Tabuas and Estreito de Miralta, two locations in Brazil endemic for intestinal schistosomiasis. The qPCR assay results were compared with those of the Kato-Katz (KK) test, examining 2 or 24 slides, Saline Gradient (SG) and "reference test" (24 KK slides + SG). The cure assessment was measured by these diagnostic techniques at 30, 90, and 180 days post-treatment. In Tabuas, the positivity rates obtained by the qPCR was 30.4% (45/148) and by "reference test" was of 31.0% (46/148), with no statistical difference (p = 0.91). The presumed cure rates at 30, 90, and 180 days post-treatment were 100, 94.4, and 78.4% by the analysis of 24 KK slides, 100, 94.4, and 78.4% by the SG, and 100, 83.3, and 62.1% by the qPCR assay. In Estreito de Miralta, the positivity obtained by qPCR was 18.3% (26/142) and with "reference test" was 24.6% (35/142), with no statistical difference (p = 0.20). The presumed cure rates were 93.3, 96.9, and 96.5% by the KK, 93.3, 96.9, and 100% by the SG, and 93.3, 93.9, and 96.5% by the qPCR at 30, 90, and 180 days post-treatment, respectively. This study showed that the diagnostic techniques presented different performance in the populations from the two districts (Tabuas and Estreito de Miralta) and reinforces the need of combining techniques to improve diagnosis accuracy, increasing the detection of individuals with low parasite burden. This combination of techniques consists an important strategy for controlling the disease transmission.

Economic impact of localized cutaneous leishmaniasis on adult patients of a referral service in Belo Horizonte, Minas Gerais State, Brazil / Impacto econômico da leishmaniose cutânea localizada em pacientes adultos em um serviço de referência em Belo Horizonte, Minas Gerais, Brasil / Impacto económico de la leishmaniosis cutánea localizada que afecta a pacientes adultos en un servicio de referencia en Belo Horizonte, Minas Gerais, Brasil

Cutaneous leishmaniasis (CL) is a disease associated with low-income populations. Thus, in assessing the burden of this disease, it is important to include its economic impact on individuals. We aimed to evaluate CL economic impact on patients treated at a referral service in the State of Minas Gerais, Brazil. This is a cross-sectional study based on the analysis of interviews and medical records from which we assembled direct medical and non-medical costs related to CL, from a societal perspective. One hundred patients were included; 50% had a monthly per capita income of up to USD 259.60 and spent on average USD 187.32 with the disease, representing an average monthly impact of 22.5% (USD 133.80). The disease imposed direct medical costs, such as: private medical appointments, medications, medical exams, dressing material, and co-participation in health insurances. Direct non-medical costs were mainly related to patients' transportation to health centers (USD 4,911.00), but also included medically-necessary care, food, and domestic and business outsourcing services. Although the Brazilian public health system guarantees access to health care, CL still represents a substantial economic impact for patients. The main action to reduce the expenses with this disease is decentralizing services for CL diagnosis and therapeutic approach, as well as increasing their efficiency.

A leishmaniose cutânea (LC) é uma doença associada a populações de baixa renda. Portanto, a inclusão do impacto financeiro sobre os pacientes é muito importante para avaliar a carga dessa doença. Tivemos como objetivo avaliar o impacto econômico da LC em pacientes afetados pela doença e tratados em um centro de referência para LC no Estado de Minas Gerais, Brasil. Foi um estudo transversal com base em análise de entrevistas e prontuários médicos para compilação dos gastos médicos e não médicos diretos relacionados à LC, desde uma perspectiva societal. Foram incluídos cem pacientes; 50% tinham renda mensal per capita de até USD 259,60. O gasto médio na doença foi de USD 187,32, o que representa um impacto mensal médio de 22,5% (USD 133,80). A doença impôs custos médicos diretos, como o pagamento por consultas médicas particulares, exames médicos, material para curativos e co-participação em seguro de saúde. Os custos não médicos diretos estiveram relacionados ao transporte dos pacientes até os centros de saúde, cuidados adicionais, alimentação e contratos com serviços terceirizados para atividades domésticas e laborais. O transporte dos pacientes para as consultas médicas representava a principal parcela dos gastos (USD 4.911,00). Embora o acesso à assistência à saúde seja um direito garantido pelo Sistema Único de Saúde, a LC ainda gera um impacto financeiro substancial para os pacientes. A descentralização dos serviços diagnósticos e terapêuticos para LC e o aumento de sua eficiência são as principais medidas que podem reduzir os gastos com essa doença.

La leishmaniosis cutánea (LC) es una enfermedad asociada a poblaciones con ingresos bajos. Por ello, incluir el impacto financiero para las personas es muy importante a la hora de evaluar la carga de esta enfermedad. Nuestro objetivo fue evaluar el impacto económico de la LC, de pacientes afectados por esta enfermedad, que fueron tratados por un servicio de referencia para el tratamiento de la LC en el Estado de Minas Gerais, Brasil. Este estudio transversal basado en entrevistas y análisis de registros médicos para la recopilación de gastos médicos y no-médicos directos, relacionados con la LC desde una a perspectiva social. Se incluyeron a cien pacientes; el 50% contaba con ingresos mensuales per cápita de hasta USD 259,60 y gastaban un promedio de USD 187,32 en la enfermedad, representando un impacto promedio mensual de 22,5% (USD 133,80). La enfermedad supuso costes médicos directos, como el pago de citas médicas privadas, medicamentos, exámenes médicos, material para vendajes, y coparticipación en seguros médicos. Los costes directos no-médicos estaban relacionados con el transporte de los pacientes a los centros de salud, el cuidado necesario, comida, y contratos con servicios externalizados para actividades domésticas y laborales. El transporte de los pacientes para citas médicas representó la principal razón para los gastos (USD 4.911,00). A pesar de que el acceso a los cuidados de salud es un derecho garantizado por el sistema de salud público brasileño, la LC todavía supone un impacto financiero importante para los pacientes. La descentralización de los servicios para el diagnóstico de LC, la aproximación terapéutica, y el incremento de su eficiencia, son las acciones con principal potencial para reducir los gastos financieros de esta enfermedad.

Intralesional infiltration versus parenteral use of meglumine antimoniate for treatment of cutaneous leishmaniasis: A cost-effectiveness analysis.

Cutaneous leishmaniasis (LC) is a complex and variable disease in terms of epidemiology, aetiology, pathology and clinical characteristics. The mainstay of treatment is still pentavalent antimony (Sbv) compounds administered systemically, despite their recognized toxicity. The advantages of antimony intralesional (IL) infiltration are the use of lower doses of Sbv and, therefore, less toxic effects. The objective of this study was to estimate the cost-effectiveness ratio of intralesional meglumine antimoniate therapy (IL-MA) compared with endovenous meglumine antimoniate therapy (EV-MA) for the treatment of CL in the context of the Brazilian National Health System (SUS). An analytical decision model (decision tree) was developed using TreeAge Pro 2018 software. Data from the open-label, uncontrolled phase II clinical trial evaluating IL-MA were used as a reference for posology, efficacy, and adverse event rates (AE). The same premises for the intravenous approach (EV-MA) were extracted from systematic literature reviews. Macro and micro calculations of spending were included in the analysis. The IL-MA and EV-MA strategies had a total cost per patient cured of US$330.81 and US$494.16, respectively. The intralesional approach was dominant, meaning it was more economic and effective than was endovenous therapy. The incremental cost-effectiveness ratio showed that IL-MA could result in savings of US$864.37 for each additional patient cured, confirming that the IL-MA strategy is cost effective in the context of the Brazilian public health scenario.

Development and Clinical Evaluation of Loop-Mediated Isothermal Amplification (LAMP) Assay for the Diagnosis of Human Visceral Leishmaniasis in Brazil.

Visceral leishmaniasis (VL) is considered a major public health concern in Brazil and several regions of the world. A recent advance in the diagnosis of infectious diseases was the development of loop-mediated isothermal amplification (LAMP). The aim of this study was to develop and evaluate a new LAMP assay for detection of K26 antigen-coding gene of L. donovani complex. A total of 219 blood samples of immunocompetent patients, including 114 VL cases and 105 non-VL cases, were analyzed for the diagnosis of VL in the present study. Diagnostic accuracy was calculated against a combination of parasitological and/or serological tests as a reference standard. The results were compared to those of kDNA Leishmania-PCR. The detection limit for the K26-Lamp assay was 1fg L. infantum purified DNA and 100 parasites/mL within 60 min of amplification time with visual detection for turbidity. The assay was specific for L. donovani complex. Sensitivity, specificity, and accuracy were 98.2%, 98.1%, and 98.2%, respectively, for K26-LAMP and 100%, 100%, and 100%, respectively, for kDNA Leishmania-PCR. Excellent agreement was observed between K26-LAMP and kDNA Leishmania-PCR assays (K = 0.96). A highly sensitive and specific LAMP assay targeting K26 antigen-coding gene of L. donovani complex was developed for diagnosis in peripheral blood samples of VL patients.

Performance of serological tests available in Brazil for the diagnosis of human visceral leishmaniasis.

BACKGROUND: Visceral leishmaniasis (VL) is the most severe form of leishmaniasis and is potentially fatal if not diagnosed and treated. Accurate and timely diagnosis is considered one of the pillars needed for the reduction in disease-related lethality. Brazil is currently one of the three eco-epidemiological hotspots for this disease. Several serological tests are commercially available in this country for VL diagnosis, although information on the performance of these tests is fragmented and insufficient. The aim of this study was to directly compare the performance of six commercial kits: three enzyme-linked immunosorbent assays (ELISAs), two immunofluorescence antibody tests (IFATs), one immunochromatographic test (ICT), besides one ICT, currently not commercially available in Brazil and one in-house direct agglutination test (DAT-LPC), not yet marketed. METHODOLOGY/PRINCIPAL FINDINGS: A panel of 236 stored samples from patients with clinically suspected VL, including 77 HIV-infected patients, was tested. IT-LEISH and DAT-LPC showed the highest accuracy rate among the non-HIV-infected patients, 96.2% [CI95%: 92.8-99.7%] and 95.6% [CI95%: 91.9-99.3%], respectively. For the ELISA tests evaluated, the maximum accuracy was 91.2%, and in the inter HIV-status group analysis, no significant differences were observed. For both IFATs evaluated, the maximum accuracy was 84.3%, and a lower accuracy rate was observed among the HIV-infected patients (p = 0.039) than among the non-HIV-infected patients. The DAT-LPC was the most accurate test in the HIV-infected patients (p≤0.115). In general, no significant difference in accuracy was observed among the VL-suspected patients stratified by age. CONCLUSIONS/SIGNIFICANCE: In summary, the differences in the performance of the tests available for VL in Brazil confirm the need for local studies before defining the diagnostic strategy.

In vitro activity and in vivo efficacy of fexinidazole against New World Leishmania species.

OBJECTIVES: To evaluate the in vitro activity and in vivo efficacy of fexinidazole against the main species that cause visceral and cutaneous New World leishmaniasis. METHODS: The inhibitory concentrations of fexinidazole against Leishmania (Leishmania) infantum chagasi, Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis in amastigotes were determined by in vitro activity assays. For the in vivo evaluation, animals were infected with L. (L.) infantum chagasi, L. (L.) amazonensis, L. (V.) braziliensis or Leishmania (Viannia) guyanensis and divided into groups: (i) control; and (ii) treated with oral fexinidazole, from 50 to 300 mg/kg/day. For cutaneous leishmaniasis, the size of the lesion was determined weekly after the beginning of the treatment. Upon completion, parasites were recovered from the spleen and liver, or skin lesion and spleen, and evaluated by a limiting dilution assay. RESULTS: All Leishmania isolates were susceptible to fexinidazole in the in vitro assays. The viable parasites in the liver and spleen were reduced with 100 and 300 mg/kg/day, respectively, for L. (L.) infantum chagasi. For the species causing cutaneous leishmaniasis, the viable parasites in lesions and the size of the lesions were reduced, starting from 200 mg/kg/day. The viable parasites in the spleen were also reduced with 200 and 300 mg/kg/day for L. (V.) braziliensis and L. (L.) amazonensis. CONCLUSIONS: Considering the defined parameters, fexinidazole showed in vitro and in vivo activity against all tested species. This drug may represent an alternative treatment for the New World species.

Diagnosis of Schistosoma mansoni infections: what are the choices in Brazilian low-endemic areas?

The population of Brazil is currently characterised by many individuals harbouring low-intensity Schistosoma mansoni infections. The Kato-Katz technique is the diagnostic method recommended by the World Health Organization (WHO) to assess these infections, but this method is not sensitive enough in the context of low egg excretion. In this regard, potential alternatives are being employed to overcome the limits of the Kato-Katz technique. In the present review, we evaluated the performance of parasitological and immunological approaches adopted in Brazilian areas. Currently, the diagnostic choices involve a combination of strategies, including the utilisation of antibody methods to screen individuals and then subsequent confirmation of positive cases by intensive parasitological investigations.

Cost-effectiveness analysis of diagnostic-therapeutic strategies for visceral leishmaniasis in Brazil.

INTRODUCTION: Visceral leishmaniasis (VL) is fatal if not diagnosed and treated. This study aimed to estimate the cost-effectiveness of diagnostic-therapeutic alternatives for VL in Brazil. METHODS: A decision model estimated the life expectancy and costs of six diagnostic-therapeutic strategies. RESULTS: IT LEISH + liposomal amphotericin B emerged the best option, presenting lower costs and higher effectiveness. DAT-LPC + liposomal amphotericin B showed an incremental cost-effectiveness ratio of US$ 326.31 per life year. CONCLUSIONS: These findings indicate the feasibility of incorporating DAT and designating liposomal amphotericin B as the first-line drug for VL in Brazil.

Desafios da implantação de testes rápidos para o diagnóstico da leishmaniose visceral em serviços de saúde de município endêmico para a doença / Challenges of the implantation of rapid tests for the diagnosis of visceral leishmaniasis in health services of a municipality endemic to the disease

O objetivo deste estudo foi descrever e discutir fatores facilitadores e desafios enfrentados durante o processo de incorporação de um teste rápido para o diagnóstico da leishmaniose visceral (LV) humana em serviços de saúde de município endêmico para a doença no Brasil. Este estudo foi dividido em quatro eixos de análise, seguindo as etapas de execução do estudo: 1) Descrição do sistema de saúde local e da tecnologia a ser implantada; 2) Contexto e atividades preparatórias; 3) Resultados da avaliação da implantação, da aceitação e do desempenho do algoritmo diagnóstico; 4) Conclusões, considerações e recomendações. O estudo foi conduzido em Ribeirão das Neves, no estado de Minas Gerais; o teste rápido implantado, o IT LEISH®, executado a partir de sangue capilar. Impasses e desafios estiveram relacionados à recusa de profissionais de saúde em realizar o IT LEISH® durante as capacitações, como dificuldade no processo de compra do teste rápido e atraso na entrega, dificuldades para coleta do sangue capilar relatada por pacientes e profissionais de saúde e falta de clareza entre os profissionais sobre suas atribuições e responsabilidades nas unidades de saúde, além de evasão de pacientes para cidade de maior porte. Este estudo apontou para a viabilidade da implantação de um teste rápido que descentralizasse e favorecesse o acesso ao diagnóstico laboratorial da LV. No entanto, no período do estudo, a maioria dos casos de LV residentes em Ribeirão das Neves foi diagnosticada em outro município, Belo Horizonte. Tal constatação aponta para desarticulação interna envolvendo os serviços de saúde do município, seja no acolhimento e na identificação dos suspeitos de LV, seja na efetiva utilização dos recursos disponíveis. Mesmo assim, identificamos dois aspectos determinantes para a realização da implantação: o engajamento de profissionais lotados em setores estratégicos da gestão municipal e a existência de financiamento. Estes resultados demonstram a complexidade do processo de implantação de uma nova tecnologia e apontam para a necessidade de trabalho integrado. Do contrário, a disponibilidade de testes rápidos para LV não será suficiente para garantir acesso e redução da letalidade pela doença.

This study aims to describe and discuss facilitating factors and challenges faced during the process of incorporating a rapid test for the diagnosis of human visceral leishmaniasis (VL) in health services of a municipality endemic to the disease in Brazil. This study was divided in four axis of analysis, following the study stages of execution: 1) Description of the local health system and the technology to be implemented; 2) Context and preparatory activities; 3) Results of evaluation of the implementation, acceptance and performance of the diagnostic algorithm; 4) Conclusions, considerations and recommendations. The study was conducted in Ribeirão das Neves, Minas Gerais and the rapid test implanted was IT LEISH®, performed from capillary blood. Impasses and challenges were related to the refusal of health professionals to perform IT LEISH® during training, difficulty in purchasing the rapid test and its delayed delivery, difficulties in capillary blood collection reported by patients and health professionals, lack of clarity among the professionals regarding their duties and responsibilities in health units, as well as avoidance of patients to a larger city. This study pointed to the feasibility of the implantation of a rapid test that decentralizes and favors the access to laboratory diagnosis of VL. However, in the study period, the majority of VL cases residing in Ribeirão das Neves were diagnosed in another municipality, Belo Horizonte. This finding points to internal disarticulation involving the health services of the municipality, either in the reception and identification of suspected LV, or in the effective use of available resources. Even so, we identified two determinant aspects for the implementation: the engagement of crowded professionals in strategic sectors of municipal management and the existence of financing. These results demonstrate the complexity of the process of implementing a new technology and point to the necessity of integrated work. Otherwise, the availability of rapid tests for LV will not be enough to guarantee access and reduction of disease lethality.