Acute Chagas disease associated with ingestion of contaminated food in Brazilian western Amazon.

OBJECTIVE: To describe clinical, epidemiological and management information on cases of acute Chagas disease (ACD) by oral transmission in the state of Amazonas in western Amazon. METHODS: Manual and electronic medical records of patients diagnosed with ACD at the Fundação de Medicina Tropical Doutor Heitor Vieira Dourado (FMT-HVD) were included. RESULTS: There were 147 cases of acute CD registered from 10 outbreaks that occurred in the state of Amazonas between 2004 and 2022. The transmission pathway was through oral route, with probable contaminated palm fruit juice (açaí and/or papatuá), and involved people from the same family, friends or neighbours. Of 147 identified cases, 87 (59%) were males; cases were aged 10 months to 82 years. The most common symptom was the febrile syndrome (123/147; 91.8%); cardiac alterations were present in 33/100 (33%), (2/147; 1.4%) had severe ACD with meningoencephalitis, and 12 (8.2%) were asymptomatic. Most cases were diagnosed through thick blood smear (132/147; 89.8%), a few (14/147; 9.5%) were diagnosed by serology and (1/147; 0.7%) by polymerase chain reaction (PCR) and blood culture. In all these outbreaks, 74.1% of the patients were analysed by PCR, and Trypanosoma cruzi TcIV was detected in all of them. No deaths were recorded. The incidence of these foci coincided with the fruit harvest period in the state of Amazonas. CONCLUSION: The occurrence of ACD outbreaks in the Amazon affected individuals of both sexes, young adults, living in rural and peri-urban areas and related to the consumption of regional foods. Early diagnosis is an important factor in surveillance. There was a low frequency of cardiac alterations. Continuous follow-up of most patients was not carried out due to difficulty in getting to specialised centres; therefore, little is known about post-treatment.

The Selvester QRS score as an estimative of myocardial injury in acute chagasic patients from the Brazilian Amazon.

BACKGROUND: In the Brazilian Amazon, a new epidemiological profile of Chagas disease transmission, the oral route, has been detected and cited as being responsible for the increase in acute cases in Brazil. The clinical evaluation of acute Chagas disease (ACD) has been a challenge since it can progress to a chronic phase with cardiac alterations, and the follow-up by modern diagnostic methods is very difficult due to the socio-geographical characteristics of the Brazilian Amazon. Thus, alternatives should be sought to alleviate this problem. We conducted a study to evaluate subjects with ACD using the 12-lead ECG QRS score (Selvester score) as an estimative of myocardial injury progression before and after ACD treatment. METHODS: The study included indigenous subjects from the Amazon region with ACD in clinical follow-up at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD) Chagas Disease outpatient clinic in the state of Amazonas, Brazil. The control group consisted of 31 healthy volunteers with no history of heart disease and no reactive serology for Chagas disease. Baseline ECG was performed in all subjects. The Selvester scoring method was performed according to the standardized guide (< 3 points: no myocardial injury,> 3: points × 3% = % of the predicted LV infarction). RESULTS: A total of 62 subjects were included, 31 as cases and 31 as controls. The mean follow-up of the case group was 17 months. The control group presented normal ECG. The case group presented 13 alterations before treatment and 11 after. Nineteen individuals presented scores > 3 points, 6 before and 13 after. In 19.36% of subjects, myocardial injury was found before treatment and in 41.94% after treatment. CONCLUSION: This is the first study that uses the Selvester score (SS) to predict myocardial injury in subjects with ACD. The results of this study suggest the significant presence of myocardial injury from the beginning of treatment to the period post treatment of ACD, which demonstrates that the SS can be applied for stratification and follow-up of Chagas disease in the Amazon region.

Identification of Pneumocystis jirovecii with Fluorescence In-Situ Hybridization (FISH) in Patient Samples-A Proof-of-Principle.

In resource-limited settings, where pneumocystosis in immunocompromised patients is infrequently observed, cost-efficient, reliable, and sensitive approaches for the diagnostic identification of Pneumocystis jirovecii in human tissue samples are desirable. Here, an in-house fluorescence in situ hybridization assay was comparatively evaluated against Grocott's staining as a reference standard with 30 paraffin-embedded tissue samples as well as against in-house real-time PCR with 30 respiratory secretions from immunocompromised patients with clinical suspicion of pneumocystosis. All pneumocystosis patients included in the study suffered from HIV/AIDS. Compared with Grocott's staining as the reference standard, sensitivity of the FISH assay was 100% (13/13), specificity was 41% (7/17), and the overall concordance was 66.7% with tissue samples. With respiratory specimens, sensitivity was 83.3% (10/12), specificity was 100% (18/18), and the overall concordance was 93.3% as compared with real-time PCR. It remained unresolved to which proportions sensitivity limitations of Grocott's staining or autofluorescence phenomena affecting the FISH assay accounted for the recorded reduced specificity with the tissue samples. The assessment confirmed Pneumocystis FISH in lung tissue as a highly sensitive screening approach; however, dissatisfying specificity in paraffin-embedded biopsies calls for confirmatory testing with other techniques in case of positive FISH screening results. In respiratory secretions, acceptable sensitivity and excellent specificity were demonstrated for the diagnostic application of the P. jirovecii-specific FISH assay.

Anopheles aquasalis transcriptome reveals autophagic responses to Plasmodium vivax midgut invasion.

BACKGROUND: Elimination of malaria depends on mastering transmission and understanding the biological basis of Plasmodium infection in the vector. The first mosquito organ to interact with the parasite is the midgut and its transcriptomic characterization during infection can reveal effective antiplasmodial responses able to limit the survival of the parasite. The vector response to Plasmodium vivax is not fully characterized, and its specificities when compared with other malaria parasites can be of fundamental interest for specific control measures. METHODS: Experimental infections were performed using a membrane-feeding device. Three groups were used: P. vivax-blood-fed, blood-fed on inactivated gametocytes, and unfed mosquitoes. Twenty-four hours after feeding, the mosquitoes were dissected and the midgut collected for transcriptomic analysis using RNAseq. Nine cDNA libraries were generated and sequenced on an Illumina HiSeq2500. Readings were checked for quality control and analysed using the Trinity platform for de novo transcriptome assembly. Transcript quantification was performed and the transcriptome was functionally annotated. Differential expression gene analysis was carried out. The role of the identified mechanisms was further explored using functional approaches. RESULTS: Forty-nine genes were identified as being differentially expressed with P. vivax infection: 34 were upregulated and 15 were downregulated. Half of the P. vivax-related differentially expressed genes could be related to autophagy; therefore, the effect of the known inhibitor (wortmannin) and activator (spermidine) was tested on the infection outcome. Autophagic activation significantly reduced the intensity and prevalence of infection. This was associated with transcription alterations of the autophagy regulating genes Beclin, DRAM and Apg8. CONCLUSIONS: Our data indicate that P. vivax invasion of An. aquasalis midgut epithelium triggers an autophagic response and its activation reduces infection. This suggests a novel mechanism that mosquitoes can use to fight Plasmodium infection.