Household ovicidal alternative for complementary control of Aedes aegypti in the Gran San Miguel de Tucuman agglomerate, Tucumán, Argentina.

Aedes aegypti is closely related to human behavior that allows its establishment through the accumulation of urban solid waste where it lays resistant eggs. Generally, adulticides and larvicides are applied in excess, without ovicidal alternatives, and some household products can help reduce the abundance of quiescent eggs in breeding sites by affecting the viability of eggs. A community involved in prevention and control is one of the most effective strategies for adequate vector management. In this investigation, new alternative strategies for the control of Ae. aegypti are assessed, valuing in laboratory the eggs' response to diverse household products. Susceptibility to different doses of bleach, oil, salt, sodium bicarbonate, vinegar, coffee, garlic, peroxide, and alcohol was measured, as well as its duration over time. New home products were found as alternative ovicidal method. Bleach and sunflower oil had an ovicidal effect at their maximum doses and at almost all of the evaluation times. In contrast, vinegar and coffee had no ovicidal effect at any time, turning out to be stimulators of hatching in the laboratory. These alternative and complementary applications could optimize the surveillance and control of Ae. aegypti in the area, allowing new approaches to reduce populations by eliminating eggs on human microhabitats.

Long-term analysis of antibodies elicited by SPUTNIK V: A prospective cohort study in Tucumán, Argentina.

BACKGROUND: Gam-COVID-Vac (SPUTNIK V) has been granted emergency use authorization in 70 nations and has been administered to millions worldwide. However, there are very few peer-reviewed studies describing its effects. Independent reports regarding safety and effectiveness could accelerate the final approval by the WHO. We aimed to study the long-term humoral immune response in naïve and previously infected volunteers who received SPUTNIK V. METHODS: Humoral immune responses, assayed by anti-SARS-CoV-2-spike-RBD IgG ELISA and neutralization assays, were measured in 602 healthcare workers at 0, 14, 28, 60 and 180 days after receiving SPUTNIK V between December 2020 and July 2021 in Tucumán, Argentina. FINDINGS: Seroconversion was detected in 97% of individuals after 28 days post-vaccination (dpv) (N = 405). Anti-RBD titers began to decrease after 60 dpv (N = 328), but remained detectable in 94% at 90 dpv (N = 224). At 180 dpv, anti-RDB titers persisted in 31% (N = 146). Previous infection triggered an increased immune response to the first dose and increased neutralization activity against variants of concern (VOC). Second doses in previously infected individuals further increased titers, even 90 dpv (N = 75). Basal antibody titers had more influence on post-vaccination anti-RBD responses than the time elapsed between diagnosis and vaccination (N = 274). INTERPRETATION: Data presented herein provides essential knowledge regarding the kinetics of antibodies induced by SPUTNIK V up to six months after immunization, and suggests that when considering one-dose vaccination policies for individuals with previous SARS-CoV-2 infection, serological studies to determine basal titers may be important, independent of when diagnosis occurred. FUNDING: Tucumán Public Health System (SIPROSA), Argentinean National Research Council (CONICET), National University of Tucumán (UNT).

Elevated Humoral Immune Response to SARS-CoV-2 at High Altitudes Revealed by an Anti-RBD "In-House" ELISA.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused a global pandemic with dramatic health and socioeconomic consequences. The Coronavirus Disease 2019 (COVID-19) challenges health systems to quickly respond by developing new diagnostic strategies that contribute to identify infected individuals, monitor infections, perform contact-tracing, and limit the spread of the virus. In this brief report, we developed a highly sensitive, specific, and precise "In-House" ELISA to correctly discriminate previously SARS-CoV-2-infected and non-infected individuals and study population seroprevalence. Among 758 individuals evaluated for anti-SARS-CoV-2 serology in the province of Tucumán, Argentina, we found a weak correlation between antibodies elicited against the RBD, the receptor-binding domain of the Spike protein, and the nucleocapsid (N) antigens of this virus. Additionally, we detected mild levels of anti-RBD IgG antibodies in 33.6% of individuals diagnosed with COVID-19, while only 19% showed sufficient antibody titers to be considered as plasma donors. No differences in IgG anti-RBD titers were found between women and men, neither in between different age groups ranging from 18 to 60. Surprisingly, individuals from a high altitude village displayed elevated and longer lasting anti-RBD titers compared to those from a lower altitude city. To our knowledge, this is the first report correlating altitude with increased humoral immune response against SARS-CoV-2 infection.

Determination of Benznidazole in Human Dried Blood Spots by Liquid Chromatography-Mass Spectrometry to Monitor Adherence to Trypanosoma cruzi Infection Treatment in Infants and Children.

Medication adherence is critical to the effectiveness of benznidazole (BZ) therapy for the treatment of Chagas disease. Assessing BZ adherence using traditional plasma sampling methods presents numerous challenges in resource-limited settings. Dried blood spot (DBS) sampling of BZ can be used to overcome logistical barriers and provides a less invasive method for assessing BZ levels. A BZ DBS assay using liquid chromatography-tandem mass spectrometry was developed and applied to a clinical study of infants and children being treated with BZ for Trypanosoma cruzi infection in Argentina. The assay was validated over a concentration range of 9.8-5,000 ng/mL. Inter-assay and intra-assay measures ranged from -2.9% to 2.7% and 0.5% to 8.3% for accuracy and from 3.5% to 12% and 1.6% to 13.6% for precision, respectively. The mean recovery of BZ was greater than 91%. Partitioning ratios for DBSs/plasma ranged from 0.95 to 1.02. A cohort of 10 infants and six children with T. cruzi infection being treated with BZ had median BZ concentrations of 1.2 (IQR 0.29, 2.14) µg/mL with seven of 65 (11%) samples above the BZ treatment goal of 3 µg/mL for adults. The reported DBS assay is a simple and accurate method for the quantitative measurement of BZ that can be applied to facilitate urgently needed clinical studies of BZ for the treatment of Chagas disease and assess BZ adherence in resource-limited settings.

Seroprevalencia de anticuerpos contra dengue en niños de uno a nueve años luego de una epidemia, Aguilares, Tucumán, 2009 / Seroprevalence of Dengue Antibodies in One-to Nine-Year-Old Children after an Outbrea, Aguilares, Tucumán 2009

INTRODUCCIÓN: El brote de dengue de 2009 constituyó el primero con casos autóctonos en Tucumán. Los departamentos de Río Chico y Capital fueron los más afectados. Hubo baja notificación de niños de uno a nueve años (2,6/1.000). Este hallazgo impulsó a conocer el real impacto del brote en la población infantil. OBJETIVO: Estimar la incidencia de dengue en niños de uno a nueve años. MÉTODOS: Se realizó un estudio transversal de sero prevalencia(IgG) en julio de 2009 en Aguilares (Departamento de Río Chico),con una muestra probabilística de niños de uno a nueve años que habían residido allí en los últimos seis meses. Los criterios de exclusión fueron: hogar inhabitado, rechazo a participar o niño con enfermedad aguda. Se utilizó una prueba de neutralización por reducciónde placas. RESULTADOS: Se obtuvieron muestras de 118 niños. Hubo 18 rechazos a participar. El 24...

INTRODUCTION: The 2009 dengue outbreak became the first with autochthonous cases in Tucumán. The departments of Río Chico and Capital were the most affecte dones. There was low incidence in one- to nine-year-old children(2.6/1000). This finding led to a study to know the real impact of the outbreak on children. OBJECTIVE: To estimate dengue incidence in one- to nine-year-old children. METHODS: Across-sectional seroprevalence (IgG) study was carried out in July 2009 in Aguilares (Department of Río Chico), with aprobability sample composed by one- to nine-year-old children who had lived there in the last six months. Exclusion criteria were: uninhabited home, refusal to participate or seriously illchild. The laboratory study consisted of a plaque reduction neutralization test. RESULTS: A total of 118 samples were obtained. There were 18 refusals to participate. 24...

Phlebotominae sand flies associated with a tegumentary leishmaniasis outbreak, Tucumán Province, Argentina.

The distribution of sand flies and cases of tegumentary leishmaniasis in the area surrounding JB Alberd city, and the proximities of Catamarca province were studied, after an increase of reported cases from JB Alberdi, Tucumán province, in 2003. Of 14 confirmed cases, 57% were females and 57% were less than 15 years old, suggesting peridomestic transmission. However, 86% of them lived close to the Marapa river forest gallery and related wooded areas. Over 1,013 sand flies were collected; Lutzomyia neivai (Pinto, 1926) was prevalent at all the sites (92.3%), while Lutzomyia migonei (França, 1920) (6.7%) and Lu. cortelezzii (Brèthes, 1923) (1%) were also found. The spatial distribution of Lu. neivai overlapped that of the cases, with higher abundance in microfocal hot spots close to the river in stable vegetated habitats or modified habitats with shadow and animal blood sources. The cumulative outcome of anthropic, ecological and climatic factors could have contributed to the onset of the outbreak.

Phlebotominae sand flies associated with a tegumentary leishmaniasis outbreak, Tucumán Province, Argentina

The distribution of sand flies and cases of tegumentary leishmaniasis in the area surrounding JB Alberd city, and the proximities of Catamarca province were studied, after an increase of reported cases from JB Alberdi, Tucumán province, in 2003. Of 14 confirmed cases, 57 percent were females and 57 percent were less than 15 years old, suggesting peridomestic transmission. However, 86 percent of them lived close to the Marapa river forest gallery and related wooded areas. Over 1,013 sand flies were collected; Lutzomyia neivai (Pinto, 1926) was prevalent at all the sites (92.3 percent), while Lutzomyia migonei (França, 1920) (6.7 percent) and Lu. cortelezzii (Brèthes, 1923) (1 percent) were also found. The spatial distribution of Lu. neivai overlapped that of the cases, with higher abundance in microfocal hot spots close to the river in stable vegetated habitats or modified habitats with shadow and animal blood sources. The cumulative outcome of anthropic, ecological and climatic factors could have contributed to the onset of the outbreak.

Após um aumento nos casos notificados na cidade de JB Alberdi, Provincia de Tucumán, no ano de 2003, foram estudados a distribuição de flebotomíneos e casos de leishmaniose tegumentar nos arredores de JB Alberdi, e na área próxima à Província de Catamarca. De 14 casos confirmados, 57 por cento foram mulheres e 57 por cento tinham menos de 15 anos de idade, sugerindo transmissão peridomiciliar. Contudo, 86 por cento dos casos residiam perto da galeria florestal do rio Marapa e perto de ilhas de vegetacão residual. De 1.013 flebotomíneos coletados, Lutzomyia neivai (Pinto, 1926) foi a espécie dominante em todos os sítios (92,3 por cento). Também, se capturaram Lutzomyia migonei (França, 1920) (6,7 por cento) e Lutzomyia cortelezzii (Brèthes, 1923) (1 por cento). A distribuicão espacial de Lu. neivai se sobrepõe com a dos casos com alta abundância em pontos quentes microfocais próximos ao rio, em habitats estáveis com vegetação, ou habitats modificados com sombras e fonte de sangue animal. O efeito acumulativo de fatores antrópicos, ecológicos e climáticos pode ter contribuido à geração do surto epidêmico.

[The prothrombotic state in early stages of chronic chagas' disease]. / Estado protrombótico en estadios tempranos de la enfermedad de Chagas crónica.

OBJECTIVE: This study was designed to explore the presence of a prothrombotic state in the early stages of chronic Chagas' disease by evaluating serum markers of thrombosis and fibrinolysis. PATIENTS AND METHOD: Forty-two patients with chronic Chagas' disease (12 men and 30 women, 32.5 6.7 years) were compared with 21 healthy volunteers (10 men and 11 women, 24.2 5.6 years). The markers of thrombotic activation used were fragment 1 + 2, ATM complex, PDF/pdf, D-dimer, and beta-thromboglobulin. Fibrinolysis was evaluated before and after venous occlusion, together with euglobulin lysis time, t-PA, and PAI-1 titers. RESULTS: The markers of thrombotic state were significantly higher in patients with chronic Chagas' disease than in controls: F1 + 2 (p < 0.0001), ATM (p < 0.0001), PDF/pdf (p < 0.05), and D dimer (p < 0.05). There was no significant difference in beta-thromboglobulin (p = 0.06). Euglobulin lysis time, a global fibrinolytic marker, differed significantly (p < 0.0001) between patients with Chagas' disease and healthy volunteers. However, the more specific fibrinolytic markers t-PA and PAI-1 did not differ significantly between the two study groups. CONCLUSIONS: Although there were no significant differences in fibrinolytic markers between patients with chronic Chagas' disease and healthy volunteers, the significant increase in thrombosis markers (F1 + 2, ATM complex, PDF/pdf, and D dimer) suggests the presence of a prothrombotic state in the early stages of chronic Chagas' disease.