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.

Olive cultivar and maturation process on the oviposition preference of Bactrocera oleae (Rossi) (Diptera: Tephritidae).

The olive fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is a key-pest in the main olives producing areas worldwide, and displays distinct preference to different olive cultivars. The present work intended to study oviposition preference towards three Portuguese cultivars (Cobrançosa, Madural, and Verdeal Transmontana) at different maturation indexes. Multiple oviposition bioassays (multiple-choice and no-choice) were conducted to assess cultivar preference. No-choice bioassays were conducted to assess the influence of different maturation indexes (MI 2; MI 3, and MI 4) in single cultivars. The longevity of olive fly adults according to the cultivar in which its larvae developed was also evaluated through survival assays.Cultivar and maturation are crucial aspects in olive fly preference. Field and laboratory assays revealed a preference towards cv. Verdeal Transmontana olives and a lower susceptibility to cv. Cobrançosa olives. A higher preference was observed for olives at MI 2 and MI 3. The slower maturation process in cv. Verdeal Transmontana (still green while the other cultivars are reddish or at black stage) seems to have an attractive effect on olive fly females, thus increasing its infestation levels. Olive fly adults from both sexes live longer if emerged from pupae developed from cv. Verdeal Transmontana fruits and live less if emerged from cv. Cobrançosa. Therefore, olive cultivar and maturation process are crucial aspects in olive fly preference, also influencing the longevity of adults.

Hospital context in surgical site infection following colorectal surgery: a multi-level logistic regression analysis.

BACKGROUND: Surgical site infections (SSIs) are associated with poor health outcomes. Their incidence is highest after colorectal surgery, with little improvement in recent years. The role of hospital characteristics is undetermined. AIM: To investigate whether SSI incidence after colorectal surgery varies between hospitals, and whether such variance may be explained by hospital characteristics. METHODS: Data were retrieved from the electronic platform of the Directorate General of Health, from 2015 to 2019. Hospital characteristics were retrieved from publicly available data on the Portuguese public administration. Analysis considered a two-level hierarchical data structure, with individuals clustered in hospitals. To avoid overfitting, no models were built with more than one hospital characteristic. Cluster-level associations are presented through median odds ratio (MOR) and intraclass cluster coefficient (ICC). Beta coefficients were used to assess the contextual effects. FINDINGS: A total of 11,219 procedures from 18 hospitals were included. The incidence of SSI was 16.8%. The ICC for the null model was 0.09. Procedural variables explained 25% of the variance, and hospital dimension explained another 17%. More than 50% of SSI variance remains unaccounted for. After adjustment, heterogeneity between hospitals (MOR: 1.51; ICC: 0.05) was still found. No hospital characteristic was significantly associated with SSI. CONCLUSION: Procedural variables and hospital dimension explain almost half of SSI variance and should be taken into account when implementing prevention strategies. Future research should focus on compliance with preventive bundles and other process indicators in hospitals with significantly less SSI in colorectal surgery.