RESUMEN
Background: The pandemic propagation of SARS-CoV-2 led to the adoption of a myriad of non-pharmacological interventions (NPIs, e.g., social distancing, mobility restrictions, gathering restrictions) in the Americas. Using national epidemiological data, here we report the impact of the layered adoption of multiple NPIs aimed at curving SARS-CoV-2 transmission in Yucatan State, Mexico. Methods: Data from suspected and laboratory confirmed COVID-19 cases during 2020 were analyzed by age groups and sex, clinical signs, and symptoms as well as outcome. The impact of NPIs was quantified using time-varying reproduction numbers (R t) estimated as a time-series and by sectors of the city. Findings: A total of 69,602 suspected cases were reported, 39.3% were laboratory-confirmed. Men were hospitalized (60.2%), more severely ill (3% vs 1.9%) and more likely to die (62%) than women. Early in the outbreak, all sectors in Merida had R t estimates above unity. Once all NPÍs were in place, R t values were dramatically reduced below one, and in the last interval transmission estimates of R t remained below one in all sectors. Interpretation: In the absence of a COVID-19 vaccination program, the combination and wide adherence of NPÍs led to a low and stable trend in SARS-CoV-2 transmission that did not overwhelm the health sector. Our study reflects that a controlled and planned ease of restrictions to balance health, social and economic recovery resulted in a single wave of transmission that prolonged at low and stable levels. Funding: GVP received funding from Emory University via the MP3 Initiative.
RESUMEN
In influenza A H1 virus, amino acids at position 190 and 225 of HA affect replication and transmission. In this study, we show that the mutation D190Y in the HA of influenza AH1N1pdm09 virus reduces the affinity of the virus for sialic acid receptors expressed at the surface of red blood cells from different species without affecting virus replication in MDCK cells.
Asunto(s)
Hemaglutininas/metabolismo , Subtipo H1N1 del Virus de la Influenza A/genética , Subtipo H1N1 del Virus de la Influenza A/metabolismo , Receptores de Superficie Celular/metabolismo , Ácidos Siálicos/metabolismo , Regulación Viral de la Expresión Génica/fisiología , Hemaglutininas/genética , MutaciónRESUMEN
A cross-sectional study was conducted to evaluate the transmission of swine influenza through occupational exposure and to assess some risk factors for zoonotic transmission in workers from commercial farms in Mexico. Seroprevalence to swine influenza subtypes was determined by hemagglutinin inhibition assay and was higher in exposed (E), in comparison with unexposed (UE) participants (P<0.05). Percentages of seropositivity between UE and E were 28.57% and 19.35% to A/NewCaledonia/20/99 (H1N1), 68.25% and 33.87% to A/Panama/2001/99-like (H3N2), 1.58% and 12.9% to A/Sw/England/163266/87 (H3N2), respectively. No antibodies were detected against A/Sw/Wisconsin/238/97 (H1N1) in the UE subjects, and only 3.22% were positive in the E group (P<0.05). A significant association between elevated antibody titres to swine influenza virus (SIV) H3N2 and the exposition to swine [OR 3.05, 95% (CI) 1.65-5.64] and to geographic location [OR 8.15, 95% (CI) 1.41-47.05] was found. Vaccination appeared as a protective factor [OR 0.05, 95% (CI) 0.01-0.52]. Farms with high number of breeding herd were associated with increased anti-SIV antibodies in the E group [OR 3.98, 95% (CI) 1.00-15.86]. These findings are relevant and support the evidence of zoonoses in swine farms and point out the need to implement preventive measures to diminish the occurrence of the disease and the potential emergence of pathogenic reassortant strains.