Virological evidence of the impact of non-pharmaceutical interventions against COVID-19 in a resource-limited setting (preprint)

Ecuador was an early COVID-19 hotspot with substantial COVID-19-mortality. In developed countries, low socioeconomic status is associated with COVID-19 infection and low compliance with non-pharmaceutical interventions (NPIs). However, if NPI were successful in resource-limited settings with high human mobility and informal labour is still unclear. We performed a retrospective observational molecular and serological study of Ecuadors reference laboratory. We tested 1,950 respiratory samples from COVID-19 surveillance for SARS-CoV-2 and 12 respiratory viruses using RT-PCR, characterized 642 SARS-CoV-2 genomes, and examined SARS-CoV-2 seroprevalence in 1,967 samples from patients with fever in Ecuadors reference laboratory during 2020-2021. Molecular and serological data were compared to NPI stringency in Bayesian, maximum-likelihood and modelling frameworks. SARS-CoV-2 (Pearson correlation test; r=-0.74; p=0.01) and other respiratory viruses (r=-0.68; p=0.02) detection correlated negatively with NPI stringency. SARS-CoV-2 seroprevalence increased from <1% during February-March 2020 to 50% within 6 weeks and plateaued after NPI implementation. Decrease of effective reproduction number <1 and antibody reactivity over time suggested intense SARS-CoV-2 transmission during pandemic onset, subsequently limited by NPIs. Phylogeographic analyses revealed that travel restrictions were implemented late not preventing 100 near-parallel SARS-CoV-2 introductions, and implementation of NPIs modified SARS-CoV-2 geographic spread by restricting recreational activity. NPIs stringency correlated negatively with the number of circulating SARS-CoV-2 lineages (r=-0.69; p=0.02). Virological evidence supports NPIs restricting human movement as an effective public health tool to control the spread of respiratory pathogens in resource-limited settings, providing a template for emerging SARS-CoV-2 variants and future epidemics.

SARS-CoV-2 transmission from infected owner to household dogs and cats is associated with food sharing.

OBJECTIVES: Several cases of reverse transmission of SARS-CoV-2 from human to pets were reported during the first year of the COVID-19 pandemic. Accordingly, the World Organization for Animal Health has recommended to improve SARS-CoV-2 surveillance on household animals to assess the risk of transmission between species. After such recommendation, we studied the potential SARS-CoV-2 infection in household dogs and cats in the city of Guayaquil, the most populated city in Ecuador. METHODS: Oral and nasal swab samples were collected from dogs and cats within 10 days of a positive SARS-CoV-2 test result of their owners. Total ribonucleic acid was extracted and detection of viral gene targets N and ORF1ab was performed by quantitative reverse transcription polymerase chain reaction. RESULTS: From the 50 cats and dogs tested, 12 were SARS-CoV-2 positive, giving a total positivity rate of 24%. A total of 1 of 8 cats tested positive, whereas 11 of 42 dogs were positive, yielding a positivity rate of 12.5% and 26.2%, respectively. SARS-CoV-2 was confirmed by whole genome sequencing. In addition, we also found a statistically significant association between SARS-CoV-2 pet positivity and food sharing with infected owners. CONCLUSION: This study is the second active surveillance of SARS-CoV-2 in household dogs and cats in Latin America. Moreover, it is the first study to address the risk factors associated with potential anthropogenic SARS-CoV-2 transmission to domestic cats and dogs. Given the high presence of free-roaming dogs and cats in rural and urban areas in Latin American countries and the high capacity shown by coronaviruses for interspecies transmission, our findings support the view that SARS-CoV-2 surveillance in pets is necessary to better understand the role that pet-human interaction plays in the COVID-19 spread.

Genomic epidemiology of SARS-CoV-2 transmission lineages in Ecuador (preprint)

Characterisation of SARS-CoV-2 genetic diversity through space and time can reveal trends in virus importation and domestic circulation, and permit the exploration of questions regarding the early transmission dynamics. Here we present a detailed description of SARS-CoV-2 genomic epidemiology in Ecuador, one of the hardest hit countries during the early stages of the COVID-19 pandemic. We generate and analyse 160 whole genome sequences sampled from all provinces of Ecuador in 2020. Molecular clock and phylgeographic analysis of these sequences in the context of global SARS-CoV-2 diversity enable us to identify and characterise individual transmission lineages within Ecuador, explore their spatiotemporal distributions, and consider their introduction and domestic circulation. Our results reveal a pattern of multiple international importations across the country, with apparent differences between key provinces. Transmission lineages were mostly introduced before the implementation of non-pharmaceutical interventions (NPIs), with differential degrees of persistence and national dissemination.