Effectiveness of contact tracing and quarantine on reducing COVID-19 transmission: a retrospective cohort study.

OBJECTIVES: Contact tracing and quarantine are common measures used in the management of infectious disease outbreaks. However, few studies have measured their impact on the control of the COVID-19 pandemic. This study aimed to assess the effectiveness of those measures on reducing transmission of severe acute respiratory syndrome coronavirus 2 in a community setting. STUDY DESIGN: The study design is a retrospective cohort study. METHODS: A retrospective cohort study of COVID-19 cases notified in Eastern Porto from March 1st to April 30th, 2020 was performed. Intervention and control cohorts were defined based on whether cases were subjected to contact tracing and quarantine measures before the laboratory confirmation of disease. The number of secondary cases per index case and the proportion of cases with subsequent secondary cases were the primary outcomes. Secondary outcomes included the time from symptom onset to specimen collection and the number of close contacts. The analysis was stratified according to whether national lockdown measures had already been implemented. RESULTS: The intervention and control cohorts comprised 98 and 453 cases, respectively. No differences were observed concerning primary outcomes. The intervention group had a shorter time between symptom onset and specimen collection (median: 3 days, interquartile range [IQR]: 1-6, vs. median: 5 days, IQR: 2-7, P-value = 0.004) and fewer close contacts (median: 0, IQR: 0-2, vs. median: 2, IQR: 1-4, P-value<0.001). The stratified analysis returned similar results. CONCLUSION: Local public health measures were effective in reducing the time between symptom onset and laboratory diagnosis and the number of close contacts per case. No effect was apparent on secondary case figures, suggesting that further measures may be required.

Dipterofauna Associated With Rat Carcasses in the Atlantic Forest, Southeastern Brazil.

Each biome has its own fauna and intrinsic local conditions that determine the succession patterns of insects on carcasses. For this reason, regional studies are very important to forensics. This study deals with the flies that visit carcasses of Rattus rattus (L., 1758) in the Atlantic Forest remnant of Floresta da Tijuca, Rio de Janeiro, Brazil. We compare the diversity and relative abundance of fly families and species throughout the four seasons of the year and test for correlations between certain environmental variables and fly richness. In each of the four seasons, we exposed the carcasses of three rats. The carcasses were put in traps that were installed on the ground, separated by 100 m. The flies were collected from the carcasses on a daily basis, and were taken to the laboratory and kept in a climate chamber (28 °C day and 26 °C night). A total of 5,537 flies were captured, identified into 12 families: Calliphoridae (4,884 specimens), followed by Sarcophagidae, Micropezidae, Fannidae, Muscidae, Phoridae, and Neridae. Canonical correspondence and redundancy analyses of the environmental variables indicated no relationship between the seasons and fly abundance. Carcass decomposition lasted longer in the winter (12 d) than in the summer (8 d). The Margalef richness index indicated higher richness in the spring and winter, and lower richness in the summer. The Shannon-Wiener index and Simpson dominance indicated greater diversity in the spring. Diptera colonized all stages of decomposition. The families Calliphoridae and Sarcophagidae were more prevalent during the Fermentation stage. Our data have important implications for forensic entomology.

Receptor Antagonist of IL-13 Exerts a Potential Negative Regulation During Early Infection of Human Schistosomiasis.

The pathology of schistosomiasis is associated with the formation of granulomas, and this process is associated with liver fibrosis. Studies indicate that Th1 cytokines reduce fibrosis in schistosomiasis, while Th2 cytokines play a part in the progression of fibrosis, and IL-13 has a critical role in this process. The IL-13Rα2 receptor, known as a 'receptor antagonist' binds with high affinity to IL-13, and studies have identified that this plays a part in reducing fibrosis and the size of granulomas. The objective of this study was to evaluate the function of IL-13Rα2 and cellular immune response in hepatic fibrosis. A negative correlation between IL-13Rα2 and IL-13 was found, suggesting an increase in cytokine in early fibrosis. Initially, a negative correlation between IFN-γ and IL-13 was found in patients without fibrosis, and subsequently, this correlation was found to be positive in patients with severe fibrosis, thereby highlighting a new mechanism for regulating the progress of periportal fibrosis. There was a positive correlation between the profiles of Th1 and Th2 cytokines, suggesting the presence of both responses, thus regulating the disease. The results contribute to a better understanding of the immune mechanisms that control the process of hepatic fibrogenesis in schistosomiasis in humans.

Molecular and morphologic analyses of expression of ESX1L in different stages of human placental development.

The mRNA expression of the ESX1L gene was analyzed by RT-PCR and in situ hybridization in human normal cytogenetically placentas, of different gestational ages. Our RT-PCR analysis showed that ESX1L mRNA is expressed from 5 weeks of gestation until term, suggesting a role not only in trophoblast differentiation but also in the maintenance of the villi and microvasculature. We also observed, by in situ hybridization, that ESX1L mRNA is expressed by cytotrophoblast from chorionic plate, syncytiotrophoblast and stromal cells of all terminal, intermediate and stem villi of term placentas. ESX1L mRNA expression was more pronounced in trophoblast cells of terminal villi than in intermediate and stem villi. In conclusion, ESX1L is expressed during all stages of placental development and is localized to sparse areas of trophoblast in terminal villi in association with cytotrophoblastic cells.