Uncovering the effects of Giardia duodenalis on the balance of DNA viruses and bacteria in children's gut microbiota.

The neglected parasitosis giardiasis is one of the most common intestinal infections worldwide, affecting mainly infants and young children. Giardia duodenalis may disturb the local microbiome, leading to intestinal ecosystem disorders, and altering different processes in the host, such as the immune response. Nevertheless, the alterations promoted by G. duodenalis on the human gut microbiome have not been thoroughly investigated. Here, we characterized the gut microbiota of G. duodenalis-infected children and determine the main alterations promoted by the parasite. To do so, fecal samples of 26 infected and four uninfected children aged 2 to 6 years old were processed for High Efficiency Microarray analysis, in order to describe their bacterial and viral profiles. Then, we quantified the total bacterial population by qPCR and assessed fecal calprotectin levels, which are closely related with gut inflammation. A total of 286 bacteria's species and 17 viruses' strains were identified. Our results revealed no statistically significant differences between G. duodenalis positive and negative groups in the taxa's phyla and families. However, bacterial species diversity was increased in children infected with G. duodenalis (p < 0.05), while the total number of bacteria was decreased (p < 0.05). Considering the virome analysis, 17 different strains were identified, 88% being bacteriophages. The correlation analysis revealed an important disruption in the balance of DNA virus and bacteria within the intestinal microbiota of Giardia-positive children. Our findings constitute the first description of the gut virome of Giardia-infected children and suggest that G. duodenalis infection exerts a modulatory effect on the gut microbiome, promoting local inflammation and altering the equilibrium of the parasite-microbiota-host triad. This highlights the importance of considering polymicrobial associations and understanding the broader context of giardiasis. Overall, our study provides new insights into the complex interactions between intestinal parasites and the microbiota, which may have implications for the development of novel therapeutic interventions in the future.

Prevalence of sexually transmissible infections in adolescents treated in a family planning outpatient clinic for adolescents in the western Amazon.

Sexually transmitted infections (STIs) are among the most common public health problems worldwide, especially among adolescents and young adults, who account for almost 50% of all STI patients. Studies on the subject in the western Amazon are limited. This study aimed to evaluate the prevalence of STIs (chlamydia, gonorrhea, trichomoniasis, herpes simplex virus, syphilis, human immunodeficiency virus [HIV], hepatitis B, and hepatitis C) in adolescents treated at a family planning outpatient clinic in the western Amazon: Porto Velho, Rondônia, Brazil. A total of 196 adolescents were enrolled. During the gynecological examination, endocervical samples were collected to test for four STIs (chlamydia, gonorrhea, trichomoniasis, and herpes simplex virus), and blood samples were collected for the detection of HIV, syphilis, and hepatitis B and C. The mean age was 17.3 ± 1.5 years, the age at sexarche was 14.4 ± 1.6 years, and 54.6% of participants had their first sexual intercourse at 14 years or younger. Only 1.0% of the adolescents used condoms in all sexual relations, and 19.9% had casual partner(s) in the last year. In the evaluation of prevalence, we found that 32% of the adolescents had at least one STI, with the most prevalent being chlamydia (23%), followed by trichomoniasis (5.6%), herpes simplex (4.6%), and gonorrhea (3.1%). No positive cases of hepatitis B, hepatitis C, or HIV were detected, but 1% of the adolescents tested positive for syphilis. These indicators will support more effective health care strategies aimed at improving the quality of life of populations in this region of the western Amazon. In conclusion, our findings demonstrated high rates of STIs in the studied patients, reinforcing the need to expand epidemiological studies to implement more appropriate public policies and intervention strategies to prevent STIs in adolescents and other vulnerable populations in the western Amazon.

Detecting Leishmania in dogs: A hierarchical-modeling approach to investigate the performance of parasitological and qPCR-based diagnostic procedures.

BACKGROUND: Domestic dogs are primary reservoir hosts of Leishmania infantum, the agent of visceral leishmaniasis. Detecting dog infections is central to epidemiological inference, disease prevention, and veterinary practice. Error-free diagnostic procedures, however, are lacking, and the performance of those available is difficult to measure in the absence of fail-safe "reference standards". Here, we illustrate how a hierarchical-modeling approach can be used to formally account for false-negative and false-positive results when investigating the process of Leishmania detection in dogs. METHODS/FINDINGS: We studied 294 field-sampled dogs of unknown infection status from a Leishmania-endemic region. We ran 350 parasitological tests (bone-marrow microscopy and culture) and 1,016 qPCR assays (blood, bone-marrow, and eye-swab samples with amplifiable DNA). Using replicate test results and site-occupancy models, we estimated (a) clinical sensitivity for each diagnostic procedure and (b) clinical specificity for qPCRs; parasitological tests were assumed 100% specific. Initial modeling revealed qPCR specificity < 94%; we tracked the source of this unexpected result to some qPCR plates having subtle signs of possible contamination. Using multi-model inference, we formally accounted for suspected plate contamination and estimated qPCR sensitivity at 49-53% across sample types and dog clinical conditions; qPCR specificity was high (95-96%), but fell to 81-82% for assays run in plates with suspected contamination. The sensitivity of parasitological procedures was low (~12-13%), but increased to ~33% (with substantial uncertainty) for bone-marrow culture in seriously-diseased dogs. Leishmania-infection frequency estimates (~49-50% across clinical conditions) were lower than observed (~60%). CONCLUSIONS: We provide statistical estimates of key performance parameters for five diagnostic procedures used to detect Leishmania in dogs. Low clinical sensitivies likely reflect the absence of Leishmania parasites/DNA in perhaps ~50-70% of samples drawn from infected dogs. Although qPCR performance was similar across sample types, non-invasive eye-swabs were overall less likely to contain amplifiable DNA. Finally, modeling was instrumental to discovering (and formally accounting for) possible qPCR-plate contamination; even with stringent negative/blank-control scoring, ~4-5% of positive qPCRs were most likely false-positives. This work shows, in sum, how hierarchical site-occupancy models can sharpen our understanding of the problem of diagnosing host infections with hard-to-detect pathogens including Leishmania.

Multiparametric analysis of host and parasite elements in new world tegumentary leishmaniasis.

Tegumentary leishmaniasis is a tropical disease caused by protozoa of the genus Leishmania. Clinically, the disease presents a broad spectrum of symptoms, the mechanisms underlying the development of lesions remaining to be fully elucidated. In the present work, we performed a correlation and multiparametric analysis to evaluate how parasite- and host-related aspects associate with each other, and with the different clinical manifestations of tegumentary leishmaniasis. This cross-sectional study involved 75 individuals from endemic areas of Brazil, grouped according to their symptoms. Leishmania species were determined by DNA sequencing, and parasite load, antibody production, and cytokine profile were evaluated by kDNA qPCR, ELISA, and flow cytometry. Data were analyzed using the Chi-square test, principal component analysis, canonical discriminant analysis, and correlation analysis. Among the recruited patients, 23 (31%) were asymptomatic, 34 (45%) had primary cutaneous leishmaniasis, 10 (13%) presented recurrent cutaneous leishmaniasis, and eight (11%) had mucocutaneous leishmaniasis. Leishmania species identified included L. amazonensis, L. braziliensis, and L. guyanensis. Surprisingly, no Leishmania RNA virus infection was detected in any sample. In summary, our work showed that parasite load, antibody production, and cytokine levels alone are not determinants for tegumentary leishmaniasis symptoms. However, the correlation analysis allowed us to observe how these factors are correlated to each other within the groups, which revealed a unique network for each clinical manifestation. Our work reinforces the complexity of tegumentary leishmaniasis outcomes - which are associated with multiple host and parasite-related elements and provides a holistic model of the disease.

Insights from the use of erythropoietin in experimental Chagas disease.

In addition to the long-established role in erythropoiesis, erythropoietin (Epo) has protective functions in a variety of tissues, including the heart. This is the most affected organ in chronic Chagas disease, caused by the protozoan Trypanosoma cruzi. Despite seven million people being infected with T. cruzi worldwide, there is no effective treatment preventing the disease progression to the chronic phase when the pathological involvement of the heart is often observed. Chronic chagasic cardiomyopathy has a wide variety of manifestations, like left ventricular systolic dysfunction, dilated cardiomyopathy, and heart failure. Since Epo may help maintain cardiac function by reducing myocardial necrosis, inflammation, and fibrosis, this study aimed to evaluate whether the Epo has positive effects on experimental Chagas disease. For that, we assessed the earlier (acute phase) and also the later (chronic phase) use of Epo in infected C57BL/6 mice. Blood cell count, biochemical parameters, parasitic load, and echocardiography data were evaluated. In addition, histopathological analysis was carried out. Our data showed that Epo had no trypanocide effect nor did it modify the production of anti-T. cruzi antibodies. Epo-treated groups exhibited parasitic burden much lower in the heart compared to blood. No pattern of hematological changes was observed combining infection with treatment with Epo. Chronic Epo administration reduced CK-MB serum activity from d0 to d180, irrespectively of T. cruzi infection. Likewise, echocardiography and histological results indicate that Epo treatment is more effective in the chronic phase of experimental Chagas disease. Since treatment is one of the greatest challenges of Chagas disease, alternative therapies should be investigated, including Epo combined with benznidazole.

Host DNA repair response to oxidative damage is modulated by Trypanosoma cruzi in a strain-dependent manner.

The conservation of genomic integrity and stability is essential for cell survival. DNA Damage Responses (DDRs) are considered of paramount importance for all living beings and involve mechanisms of cell cycle regulation and damage-specific DNA repair pathways. Hydrogen peroxide (H2O2) is a compound that, in supraphysiological concentrations, damages biomolecules including the DNA, causing base modifications and strand breaks. There is evidence that Trypanosoma cruzi, the protozoan that causes Chagas disease, interferes in the host cell's DNA metabolism. In order to investigate the influence of T. cruzi infection over the host cell capacity to withstand and repair DNA damage, we analyzed L6 cells infected with Berenice, and Colombiana T. cruzi strains according to their viability, proliferation, morphology, DNA degradation, expression of DNA repair, and cell cycle genes following H2O2 treatment. It was noted that T. cruzi infection might act as either a stressor or a protective element of host DNA, depending on the strain and H2O2 concentration. Cells infected with Berenice strain and treated with 0.8 mM H2O2 presented a reduced DNA damage response intensity (e.g., BER and HR). Infection with T. cruzi Colombiana prevented the activation of DNA repair pathways in response to 0.8mM and 1.6mM H2O2 (NER and MMR). Nevertheless, since cellular viability was not significantly compromised in Colombiana-infected cells following the oxidative insult, it is possible that the parasite directly influenced the host DNA repair machinery. Our results support the notion that T. cruzi is able to modulate the host cell DNA metabolism in a strain-dependent manner, an event which can be explored in future drug development strategies.

Seroprevalence of Trypanosoma cruzi in pregnant women in Midwest Brazil: an evaluation of congenital transmission.

Chagas disease (CD) is caused by the protozoan Trypanosoma cruzi and it is mainly acquired through the vector route, however, blood transfusion and congenital transmission are implicated in the spread of the illness worldwide. The congenital route can occur at any stage of pregnancy and its frequency varies. In the Federal District, in Brazil, the frequency of T. cruzi infection in pregnant women and their offspring has not been updated. Thus, the aim of this study was to estimate the prevalence of T. cruzi infection in pregnant women and the rate of congenital transmission in the Federal District. A cross-sectional study was conducted to estimate the seroprevalence of T. cruzi from 2014 to 2016 in the population of pregnant women attended by the public health service throughout the Federal District and a descriptive cohort for the evaluation of congenital transmission. During the study, prenatal data of 98,895 women were consulted and pregnant women registered in 2016, presenting with positive T. cruzi serology, were part of the descriptive cohort. The estimated prevalence of T. cruzi infection in the three years was 0.19% and the congenital transmission rate was 1/40 (2.5%). Our results have shown that, although the main routes of transmission of CD have been interrupted, there is still a risk of congenital transmission in the Federal District. This present study highlights the need for the continuous implementation of a screening program for pregnant women and timely treatment of infected newborns and children.

Clinical and biochemical parameters of COVID-19 patients with prior or active dengue fever.

Originated in Wuhan, China, the coronavirus 19 disease (COVID-19) has quickly spread worldwide, reaching countries that already faced other endemics and epidemics. In Brazil, such a concerning situation includes arboviruses, among which the dengue virus stands out. Here, we determined the rate of SARS-CoV-2/dengue virus co-infection in a total of 178 patients with COVID-19 symtoms admitted into a large public hospital of the Federal District of Brazil. Furthermore, we evaluated whether prior or active dengue virus infection influenced hematological, biochemical, and clinical parameters of such patients. One hundred and twelve (63%) individuals tested positive for COVID-19, of which 43 (38.4%) were co-infected with dengue virus, and 50 (44.6%) had antibodies indicative of previous dengue infection. Co-infected patients showed lower numbers of circulating lymphocytes and monocytes, higher glucose rates, and a worse pulmonary condition. Of note, prior infections with dengue virus did not influence clinical parameters, but active dengue fever resulted in higher hospitalization rate. In conclusion, amid the current complex epidemiological scenario in Brazil, our data support the notion that SARS-CoV-2 and dengue co-infection affects an important percentage of COVID-19 patients and leads to worse clinical parameters, requiring greater attention from health authorities.

Measuring mosquito control: adult-mosquito catches vs egg-trap data as endpoints of a cluster-randomized controlled trial of mosquito-disseminated pyriproxyfen.

BACKGROUND: Aedes aegypti and Culex quinquefasciatus are the main urban vectors of arthropod-borne viruses causing human disease, including dengue, Zika, or West Nile. Although key to disease prevention, urban-mosquito control has met only limited success. Alternative vector-control tactics are therefore being developed and tested, often using entomological endpoints to measure impact. Here, we test one promising alternative and assess how three such endpoints perform at measuring its effects. METHODS: We conducted a 16-month, two-arm, cluster-randomized controlled trial (CRCT) of mosquito-disseminated pyriproxyfen (MD-PPF) in central-western Brazil. We used three entomological endpoints: adult-mosquito density as directly measured by active aspiration of adult mosquitoes, and egg-trap-based indices of female Aedes presence (proportion of positive egg-traps) and possibly abundance (number of eggs per egg-trap). Using generalized linear mixed models, we estimated MD-PPF effects on these endpoints while accounting for the non-independence of repeated observations and for intervention-unrelated sources of spatial-temporal variation. RESULTS: On average, MD-PPF reduced adult-mosquito density by 66.3% (95% confidence interval, 95% CI: 47.3-78.4%); Cx. quinquefasciatus density fell by 55.5% (95% CI: 21.1-74.8%), and Ae. aegypti density by 60.0% (95% CI: 28.7-77.5%). In contrast, MD-PPF had no measurable effect on either Aedes egg counts or egg-trap positivity, both of which decreased somewhat in the intervention cluster but also in the control cluster. Egg-trap data, therefore, failed to reflect the 60.0% mean reduction of adult Aedes density associated with MD-PPF deployment. CONCLUSIONS: Our results suggest that the widely used egg-trap-based monitoring may poorly measure the impact of Aedes control; even if more costly, direct monitoring of the adult mosquito population is likely to provide a much more realistic and informative picture of intervention effects. In our CRCT, MD-PPF reduced adult-mosquito density by 66.3% in a medium-sized, spatially non-isolated, tropical urban neighborhood. Broader-scale trials will be necessary to measure MD-PPF impact on arboviral-disease transmission.

Current trends in the pharmacological management of Chagas disease.

Chagas disease (CD) is a tropical neglected illness, affecting mainly populations of low socioeconomic status in Latin America. An estimated 6 to 8 million people worldwide are infected with Trypanosoma cruzi, the etiological agent of CD. Despite being one of the main global health problems, this disease continues without effective treatment during the chronic phase of the infection. The limitation of therapeutic strategies has been one of the biggest challenges on the fight against CD. Nifurtimox and benznidazole, developed in the 1970s, are still the only commercial options with established efficacy on CD. However, the efficacy of these drugs have a proven efficacy only during early infection and the benefits in the chronic phase are questionable. Consequently, there is a growing need for new pharmacological alternatives, either by optimization of existing drugs or by the formulation of new compounds. In the present study, a literature review of the currently adopted therapy, its concomitant combination with other drugs, and potential future treatments for CD was performed, considering articles published from 2012. The revised articles were selected according to the protocol of treatment: evaluation of drug association, drug repositioning and research of new drugs. As a result of the present revision, it was possible to conclude that the use of benznidazole in combination with other compounds showed better results when compared with its use as a single therapy. The search of new drugs has been the strategy most used in pursuing more effective forms of treatment for CD. However, studies have still focused on basic research, that is, they are still in a pre-clinical stage, using methodologies based on in vitro or in animal studies.

In vitro models for investigation of the host-parasite interface - possible applications in acute Chagas disease.

Chagas disease (CD), caused by Trypanosoma cruzi, is the main parasitic disease in the Western Hemisphere, with an increasing number of cases, especially in non-endemic regions. The disease is characterized by cardiomegaly and mega viscera, nevertheless, the clinical outcome is hard to predict, underscoring the need for further research into the pathophysiology of CD. Even though most basic and translational research involving CD is performed using in vivo models, in vitro models arise as an ethical, rapidly evolving, and physiologically relevant alternative for CD research. In the present review, we discuss the past and recent in vitro models available to study the host-parasite interface in cardiac and intestinal CD, critically analyzing the possibilities and limitations of state-of-the-art alternatives for the CD host-parasite investigation.

Trypanosomatid infections in captive wild mammals and potential vectors at the Brasilia Zoo, Federal District, Brazil.

BACKGROUND: Conservation projects in zoos may involve translocation of captive animals, which may lead to pathogen spread. Neotropical mammals are important hosts of Trypanosoma cruzi and Leishmania spp. the etiological agents of Chagas disease and Leishmaniasis respectively. Studies of trypanosomatid-infected mammals and vectors (triatomines and sandflies) in zoos are important for the establishment of surveillance and control measures. OBJECTIVES: We investigated trypanosomatid infections in captive wild mammals, triatomines and sandflies at the Brasília Zoo. METHODS: We collected triatomines during active bimonthly surveys, sampled sandflies using light-traps and obtained blood samples from 74 mammals between 2016 and 2017. We used quantitative PCR to detect trypanosomatids in vectors and mammals. RESULTS: We found a colony of 19 Panstrongylus megistus in the porcupine unit and detected T. cruzi infections in five bugs. We captured 17 sandflies of four species including Nyssomyia whitmani and Lutzomyia longipalpis, but no Leishmania infection was detected. qPCR detected 50 T. cruzi-infected mammals belonging to 24 species and five groups of mammals (Carnivora, Cetartiodactyla, Perissodactyla, Pilosa and Primates); Leishmania DNA was detected in 23 mammals from 15 species, mainly carnivores. We detected trypanosomatid infections in 11 mammals born at the Brasília Zoo. CONCLUSIONS: Our results suggest vector-borne transmission of T. cruzi among maned wolves; measures to reduce the risk of new infections should therefore be taken. We also report sandfly presence and Leishmania-infected mammals at the Brasília Zoo. Translocation of wild mammals in and out of the Brasília Zoo should consider the risk of T. cruzi and Leishmania spread.

Correlation of Parasite Burden, kDNA Integration, Autoreactive Antibodies, and Cytokine Pattern in the Pathophysiology of Chagas Disease.

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi (T. cruzi), is the main parasitic disease in the Western Hemisphere. Unfortunately, its physiopathology is not completely understood, and cardiomegaly development is hard to predict. Trying to explain tissue lesion and the fact that only a percentage of the infected individuals develops clinical manifestations, a variety of mechanisms have been suggested as the provokers of CD, such as parasite persistence and autoimmune responses. However, holistic analysis of how parasite and host-related elements may connect to each other and influence clinical outcome is still scarce in the literature. Here, we investigated murine models of CD caused by three different pathogen strains: Colombian, CL Brener and Y strains, and employed parasitological and immunological tests to determine parasite load, antibody reactivity, and cytokine production during the acute and chronic phases of the disease. Also, we developed a quantitative PCR (qPCR) protocol to quantify T. cruzi kDNA minicircle integration into the mammalian host genome. Finally, we used a correlation analysis to interconnect parasite- and host-related factors over time. Higher parasite load in the heart and in the intestine was significantly associated with IgG raised against host cardiac proteins. Also, increased heart and bone marrow parasitism was associated with a more intense leukocyte infiltration. kDNA integration rates correlated to the levels of IgG antibodies reactive to host cardiac proteins and interferon production, both influencing tissue inflammation. In conclusion, our results shed light into how inflammatory process associates with parasite load, kDNA transfer to the host, autoreactive autoantibody production and cytokine profile. Altogether, our data support the proposal of an updated integrative theory regarding CD pathophysiology.

The use of qPCR in human Chagas disease: a systematic review.

Introduction: The diagnosis in Chagas disease is a challenge because most infections with Trypanosoma cruzi are asymptomatic and currently serological tests have limitations, such as cross-reactivity with other trypanosomatids. Real-time PCR (qPCR) is a useful procedure that allows T. cruzi detection even when the parasitic load is very low and seems interesting for monitoring the response to trypanocidal treatment and elucidating cases with doubtful serological results. Areas covered: This systematic review aimed to investigate the applications and relevance of qPCR in human Chagas disease, and focus on the methodological aspects. Expert opinion: The results showed that blood samples with the TaqMan procedure direct to nuclear DNA (nDNA) sequences are used the most. However, a high variability among laboratories concerning the qPCR methods make it difficult to compare between studies and the use in routine surveillance laboratories, even if some works had performed an analytical validation of T. cruzi qPCR to try to counteract this. Nevertheless, the detection of T. cruzi by qPCR has multiple advantages including fast results, reduction of carryover contamination compared to conventional PCR, and high sensitivity and specificity. This study has given an overview of assays using qPCR in human Chagas disease and has shown the relevance of this technique in diagnosis.

Intestinal microbiota - A modulator of the Trypanosoma cruzi-vector-host triad.

Chagas disease affects millions of people, and it is a major cause of death in Latin America. Prevention and development of an effective treatment for this infection can be favored by a more thorough understanding of T. cruzi interaction with the microbiome of vectors and hosts. Next-generation sequencing technology vastly broadened the knowledge about intestinal bacteria composition, showing that microbiota within each host (triatomines and mammals) is composed by high diversity of species, although few dominant phyla. This fact may represent an ecological balance that was acquired during the evolutionary process of the microbiome-host complex, and that serves to perpetuate this system. In this context, commensal microbiota is also essential to protect hosts, conferring them resistance to pathogens colonization. However, in some situations, the microbiota is not able to prevent infection but only modulate it. Here we will review the role of the microbiota on the parasite-vector-host triad with a focus on the kinetoplastida of medical importance Trypanosoma cruzi. Novel strategies to control Chagas disease based on intestinal microbiome will also be discussed.

Congenital Chagas disease: alert of research negligence.

INTRODUCTION: Chagas disease (CD), a neglected endemic disease in Latin America, has acquired new epidemiological characteristics with an increase in the importance of alternative transmission routes such as congenital transmission. We evaluated the scientific research on this subject. METHODS: We searched the Scielo, BVS, and PubMed databases from 2006 to 2017. RESULTS: We identified a small number of published articles, mostly in journals with an impact factor less than 3.0. Studies on human congenital transmission of CD were carried out in only seven different countries. CONCLUSIONS: Our data highlight the lack of research on congenital CD.

Improving the reference standard for the diagnosis of canine visceral leishmaniasis: a challenge for current and future tests.

BACKGROUND: Studies aimed at validating canine visceral leishmaniasis diagnostic tests present heterogeneous results regarding test accuracy, partly due to divergences in reference standards used and different infection evolution periods in animals. OBJECTIVE: This study aimed to evaluate the accuracy of the rapid test-dual path platform (TR-DPP) (Biomanguinhos®), EIE-Leishmaniose-Visceral-Canina-Biomanguinhos (EIE-LVC) (Biomanguinhos®), enzyme-linked immunosorbent assay (ELISA) rK39 (in-house), and the direct agglutination test (DAT-Canis) against a reference standard comprising parasitological and molecular techniques. METHODS: A phase II/III validation study was carried out in sample sera from 123 predominantly asymptomatic dogs living in an area endemic for visceral leishmaniasis. FINDINGS: Sixty-nine (56.1%) animals were considered infected according to the reference standard. For each test, the sensitivity and specificity, respectively, were as follows: TR-DPP, 21.74% [confidence interval (CI)95% 13.64% to 32.82%] and 92.59% (CI95% 82.45% to 97.08%); EIE-LVC, 11.59% (CI95% 5.9% to 21.25%) and 90.74% (CI95% 80.09% to 95.98%); ELISA rK39, 37.68% (CI95% 27.18% to 49.48%) and 83.33% (CI95% 71.26% to 90.98%); and DAT-Canis, 18.84% (CI95% 11.35% to 29.61%) and 96.30% (CI95% 87.46% to 98.98%). CONCLUSION: We concluded that improving the sensitivity of serum testing for diagnosing asymptomatic dogs must constitute a priority in the process of developing new diagnostic tests to be used in the visceral leishmaniasis control program in Brazil.

Improving the reference standard for the diagnosis of canine visceral leishmaniasis: a challenge for current and future tests

BACKGROUND Studies aimed at validating canine visceral leishmaniasis diagnostic tests present heterogeneous results regarding test accuracy, partly due to divergences in reference standards used and different infection evolution periods in animals. OBJECTIVE This study aimed to evaluate the accuracy of the rapid test-dual path platform (TR-DPP) (Biomanguinhos®), EIE-Leishmaniose-Visceral-Canina-Biomanguinhos (EIE-LVC) (Biomanguinhos®), enzyme-linked immunosorbent assay (ELISA) rK39 (in-house), and the direct agglutination test (DAT-Canis) against a reference standard comprising parasitological and molecular techniques. METHODS A phase II/III validation study was carried out in sample sera from 123 predominantly asymptomatic dogs living in an area endemic for visceral leishmaniasis. FINDINGS Sixty-nine (56.1%) animals were considered infected according to the reference standard. For each test, the sensitivity and specificity, respectively, were as follows: TR-DPP, 21.74% [confidence interval (CI)95% 13.64% to 32.82%] and 92.59% (CI95% 82.45% to 97.08%); EIE-LVC, 11.59% (CI95% 5.9% to 21.25%) and 90.74% (CI95% 80.09% to 95.98%); ELISA rK39, 37.68% (CI95% 27.18% to 49.48%) and 83.33% (CI95% 71.26% to 90.98%); and DAT-Canis, 18.84% (CI95% 11.35% to 29.61%) and 96.30% (CI95% 87.46% to 98.98%). CONCLUSION We concluded that improving the sensitivity of serum testing for diagnosing asymptomatic dogs must constitute a priority in the process of developing new diagnostic tests to be used in the visceral leishmaniasis control program in Brazil.

Congenital Chagas disease: alert of research negligence

Abstract INTRODUCTION: Chagas disease (CD), a neglected endemic disease in Latin America, has acquired new epidemiological characteristics with an increase in the importance of alternative transmission routes such as congenital transmission. We evaluated the scientific research on this subject. METHODS: We searched the Scielo, BVS, and PubMed databases from 2006 to 2017. RESULTS: We identified a small number of published articles, mostly in journals with an impact factor less than 3.0. Studies on human congenital transmission of CD were carried out in only seven different countries. CONCLUSIONS: Our data highlight the lack of research on congenital CD.

The first Acanthamoeba keratitis case in the Midwest region of Brazil: diagnosis, genotyping of the parasite and disease outcome.

We report an Acanthamoeba keratitis case associated with the use of contact lens in a 28-year-old female from Brasília, Brazil. Samples from corneal scraping and contact lens case were used for culture establishment, PCR amplification, and partial sequencing (fragments of ~400kb) of small subunit rDNA; both culture and PCR were positive. The sequence analyses of the cornea and of isolates from the contact lens case showed similarity with the T4 genotype. To the best of our knowledge, this is the first report of T4 Acanthamoeba keratitis case from the Midwest region of Brazil.