Was Chagas disease responsible for Darwin’s illness? The overlooked eco-epidemiological context in Chile

The source of Darwin’s illness has been a contentious issue in the literature for almost 70 years. Different causal factors have been invoked to account for his symptoms, including Chagas disease. The Chagas hypothesis is based upon Darwin’s diary, in which he narrates his experience with kissing bugs, the main vector of the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. In this contribution, we examine the consistency of the “Chagas disease hypothesis” in the light of current ecological and epidemiological knowledge of the disease in Chile. According to his diary and letters, during his overland trips, Darwin slept in rural houses and outdoors for 128 days in a “hyperendemic” area for Chagas disease, more than exposing him to kissing bugs. This observation conveys a likely additional source of infection than previously considered, which might reinforce the idea that Chagas disease contributed to Darwin’s manifest physical deterioration.

Unhealthy Behaviors and Metabolic Indices of Chronic Kidney Disease in a HCV Hyperendemic Area: A Community-Based Study

Background: Hepatitis C virus (HCV) infection is related to a higher risk of chronic kidney disease (CKD). This study aimed to investigate the relationships between unhealthy behaviors, metabolic indices, and HCV with CKD.Methods: This cross-sectional study was conducted as part of a community health promotion program in the HCV hyperendemic area of Taiwan between March and December 2019. Multivariable logistic regression analyses adjusted for demographic and clinical characteristics were performed to investigate the association between CKD and HCV seropositivity.Results: A total of 2,387 patients completed the examination. HCV was related to a lower estimated glomerular filtration rate (eGFR), unhealthy dietary behaviors, and multiple metabolic indices including higher systolic blood pressure (SBP), glycosylated hemoglobin (HbA1c), and triglycerides (TG), and lower high-density lipoprotein (HDL). HCV was associated with a 44% higher risk of CKD compared to non-HCV (OR 1.44, 95% confidence interval [CI] 1.05-1.98). Irregular exercise, waist circumference (WC), and higher HbA1c were significantly associated with a higher risk of CKD after multivariable analysis. A low eGFR was significantly associated with the severity of metabolic syndrome (MetS) in the HCV group (median eGFR of 86.4, 77.1, and 64.5 mL/min/1.73 m2 for individuals with one, three, and five MetS components, respectively).Conclusions: HCV seropositivity, metabolic distortion, and irregular exercise are significantly associated with CKD. Effective treatment of HCV and aggressive health promotion of physical activity may prevent the occurrence of CKD.

Ocular lesions in a domestic feline:

Sporotrichosis is a dermatozoonosis, caused by dimorphic pathogenic fungi of the genus Sporothrix. Although Sporothrix brasiliensis is the most frequent and pathogenic species identified from the Brazilian sporotrichosis hyperendemic, to the best of our knowledge this is the first report of its molecular diagnosis from a cat with ocular lesions. A 3-month old female, domestic feline presented an ocular manifestation with granuloma in the lower-left palpebral conjunctiva, in addition to mucocutaneous lesions in varied locations throughout the body. Samples were collected for subsequent cytopathology, fungal culture, serology, and molecular genotyping. Itraconazole was prescribed for the treatment of sporotrichosis and the animal was considered clinically cured at the end of 5 months of treatment and discharged. S. brasiliensis cat interactions can manifest with a multitude of clinical forms that resemble either infectious or noninfectious diseases. Both the need for meticulous cat physical evaluation by a veterinarian followed by accurate laboratory diagnosis are key Public Health measures in the Brazilian sporotrichosis hyperendemic area.

Does Antibody Avidity to Plasmodium falciparum Merozoite Antigens increase with Age in Individuals living in Malaria-Endemic Areas?

Introduction: High avidity antibodies (Abs) are acquired after a few Plasmodium falciparum infections in low transmission areas, but it remains unclear if Ab avidity to different merozoite antigens increases with age in individuals with persistent antigenemia and if so, when a fully mature Ab response occurs. Methods: The study used plasma samples collected between 1996 and 1998 from 566 individuals aged 4-84 years in Simbok, Cameroon where residents received an estimated 1.6 infectious mosquito bites/person/night. Plasma samples were examined for Ab levels (median fluorescence intensity, MFI) and Ab avidity index (AI = [MFI after treatment with 2M NH4SCN/MFI without salt] x 100) using a bead-based multiplex immunoassay for recombinant AMA1, EBA-175, MSP1-42 (3D7, FVO), MSP2 (3D7, Fc27), and MSP3. Results: Blood-smear positivity for P. falciparum declined with age from 54.3% at 4-5 years to 18% at 16-40 years and <11% at >40 years of age, although most individuals had submicroscopic parasitemia. Ab affinity maturation, based on age-related patterns of median AI, percent of individuals with AI ≥50 and strength of association between MFI and AI, occurred at different rates among the antigens: developing rapidly before age 4 years for AMA1, increasing gradually with age for EBA-175 and MSP1 until ∼16-25 years, but occurring negligibly for MSP2 and MSP3. Conclusion: In a hyperendemic area with perennial transmission, affinity maturation resulting in an increase in the proportion of high avidity Abs occurred for some merozoite antigens, in parallel with a decline in malaria slide passivity, but not for others.

Significant amelioration of hepatitis C virus infection in a hyperendemic area: longitudinal evidence from the COMPACT Study in Taiwan

ObjectivesHepatitis C virus (HCV) infection is the leading cause of cirrhosis and hepatocellular carcinoma worldwide. Tzukuan, located in the southwestern area of Taiwan, is an HCV hyperendemic area (>30%). This study aimed to assess the changing epidemiological characteristics of HCV infection and to evaluate the long-term outcomes after the implementation of public health strategies for two decades.DesignA population-based retrospective cohort study.SettingA comprehensive care programme was implemented, namely COMPACT Study, in Tzukuan since 1997.ParticipantsA total of 10 714 residents participated the screening.Outcome measuresThe HCV status, demographic and clinical profiles of the participants were recorded and validated annually from 2000 through 2019.ResultsThe HCV infection prevalence rates were 21.1% (1076/5099) in 2000–2004, 18.8% (239/1269) in 2005–2009, 14.1% (292/2071) in 2010–2014 and 10.3% (234/2275) in 2015–2019 (p for trend test <0.0001). Among them, 1614 underwent repeated tests during the follow-up period. The annual incidence rates were 0.54% in 2005–2009, 0.4% in 2010–2014 and 0.22% in 2015–2019, respectively (p=0.01). In addition to old age, lower education level was a major risk factor for HCV infection across different periods. HCV infection prevalence rate among those illiterates reached 40.9%, followed by 28.5% in those with elementary school level, and <10% in those with high school or higher levels. The major risk factor has shifted from iatrogenic exposure in 2000–2009 to household transmission after 2010.ConclusionsHCV infection has been decreasing and the epidemiological features are changing in the hyperendemic area by continuing education, prevention and treatment strategies.

Predicting the detection of leprosy in a hyperendemic area of Brazil: Using time series analysis

Background: Brazil has the second highest prevalence of leprosy worldwide. Autoregressive integrated moving average models are useful tools in surveillance systems because they provide reliable forecasts from epidemiological time series. Aim: To evaluate the temporal patterns of leprosy detection from 2001 to 2015 and forecast for 2020 in a hyperendemic area in northeastern Brazil. Methods: A cross-sectional study was conducted using monthly leprosy detection from the Brazil information system for notifiable diseases. The Box–Jenkins method was applied to fit a seasonal autoregressive integrated moving average model. Forecasting models (95% prediction interval) were developed to predict leprosy detection for 2020. Results: A total of 44,578 cases were registered with a mean of 247.7 cases per month. The best-fitted model to make forecasts was the seasonal autoregressive integrated moving average ((1,1,1); (1,1,1)). It was predicted 0.32 cases/100,000 inhabitants to January of 2016 and 0.38 cases/100,000 inhabitants to December of 2020. Limitations: This study used secondary data from Brazil information system for notifiable diseases; hence, leprosy data may be underreported. Conclusion: The forecast for leprosy detection rate for December 2020 was < 1 case/100,000 inhabitants. Seasonal autoregressive integrated moving average model has been shown to be appropriate and could be used to forecast leprosy detection rates. Thus, this strategy can be used to facilitate prevention and elimination programmes.