Prevalence of SARS-CoV-2 infection in Baja California, Mexico: Findings from a community-based survey in February 2021 in the Mexico-United States border.

Between March 2020 and February 2021, the state of Baja California, Mexico, which borders the United States, registered 46,118 confirmed cases of COVID-19 with a mortality rate of 238.2 deaths per 100,000 residents. Given limited access to testing, the population prevalence of SARS-CoV-2 infection is unknown. The objective of this study is to estimate the seroprevalence and real time polymerase chain reaction (RT-PCR) prevalence of SARS-CoV-2 infection in the three most populous cities of Baja California prior to scale-up of a national COVID-19 vaccination campaign. Probabilistic three-stage clustered sampling was used to conduct a population-based household survey of residents five years and older in the three cities. RT-PCR testing was performed on nasopharyngeal swabs and SARS-CoV-2 seropositivity was determined by IgG antibody testing using fingerstick blood samples. An interviewer-administered questionnaire assessed participants' knowledge, attitudes, and preventive practices regarding COVID-19. In total, 1,126 individuals (unweighted sample) were surveyed across the three cities. Overall prevalence of SARS-CoV-2 infection by RT-PCR was 7.8% (95% CI 5.5-11.0) and IgG seroprevalence was 21.1% (95% CI 17.4-25.2). There was no association between border crossing in the past 6 months and SARS-CoV-2 prevalence (unadjusted OR 0.40, 95%CI 0.12-1.30). While face mask use and frequent hand washing were common among participants, quarantine or social isolation at home to prevent infection was not. Regarding vaccination willingness, 30.4% (95% CI 24.4-3 7.1) of participants said they were very unlikely to get vaccinated. Given the high prevalence of active SARS-CoV-2 infection in Baja California at the end of the first year of the pandemic, combined with its low seroprevalence and the considerable proportion of vaccine hesitancy, this important area along the Mexico-United States border faces major challenges in terms of health literacy and vaccine uptake, which need to be further explored, along with its implications for border restrictions in future epidemics.

Isolation and Cytotoxic Activity of Phyllocladanes from the Roots of Acacia schaffneri (Leguminosae).

In research on natural molecules with cytotoxic activity that can be used for the development of new anticancer agents, the cytotoxic activity of hexane, chloroform, and methanol extracts from the roots of Acacia schaffneri against colon, lung, and skin cancer cell lines was explored. The hexane extract showed the best activity with an average IC50 of 10.6 µg mL-1. From this extract, three diterpenoids, phyllocladan-16α,19-diol (1), phyllocladan-16α-ol (2), and phylloclad-16-en-3-ol (3), were isolated and characterized by their physical and spectroscopic properties. Diterpenoids 1 and 2 were tested against the same cancer cell lines, as well as their healthy counterparts, CCD841 CoN, MRC5, and VH10, respectively. Compound 1 showed moderate activity (IC50 values between 24 and 70 µg mL-1), although it showed a selective effect against cancer cell lines. Compound 2 was practically inactive. The cytotoxicity mechanism of 1 was analyzed by cell cycle, indicating that the compound induces G0/G1 cell cycle arrest. This effect might be generated by DNA alkylation damage. In addition, compound 1 decreased migration of HT29 cells.