1. The population status of the coastal bottlenose dolphin (Tursiops truncatus) inhabiting the inner estuary of the Gulf of Guayaquil, Ecuador (3°S, 81°W) was assessed. Evaluated aspects included social organization, abundance and spatial distribution.2. Surveys focused on the western part of the estuary (Posorja and Estero Salado) but other areas in the central and eastern inner estuary were also surveyed.3. Effort included 68 trips, 5001 km of survey and 288.8 h at sea. Between 735 and 793 dolphins in 92 groups were recorded during the study. 4. Dolphins are not evenly distributed but concentrated their activities in the mouths of large channels. 5.A cluster analyses indicated that dolphins organize in partially discrete subunits referred to as communities.6. Abundance estimations were obtained using mark-recapture modelling for two communities:Posorja and Estero Salado (43 dolphins, 95% CI 37-49 and 65 dolphins, 95% CI 52-82 respectively). 7. Four demographic parameters: average size of communities, average group size, average encounter rate and average density were compared with information obtained during the 1990s. In all cases the current values were between 39 and 54% lower; in the last three cases the difference was statistically significant.8. Possible causes of this apparent decline include bycatch, ship strikes, pollution and habitat degradation; however, none of these have been assessed in depth. Most probably, different stressors are affecting dolphin communities to different extents. 9. A comprehensive assessment of the whole population inside the gulf is needed. Identifying major threats is a priority to define concrete actions to prevent further population decline.

The common bottlenose dolphin, Tursiops truncatus, is widely distributed along the western coast of South America. In Ecuador, a resident population of bottlenose dolphins inhabits the inner estuarine area of the Gulf of Guayaquil located in the southwestern part of the country and is under threat from different human activities in the area. Only one genetic study on South American common bottlenose dolphins has been carried out to date, and understanding genetic variation of wildlife populations, especially species that are identified as threatened, is crucial for defining conservation units and developing appropriate conservation strategies. In order to evaluate the evolutionary link of this population, we assessed the phylogenetic relationships, phylogeographic patterns, and population structure using mitochondrial DNA (mtDNA). The sampling comprised: (i) 31 skin samples collected from free-ranging dolphins at three locations in the Gulf of Guayaquil inner estuary, (ii) 38 samples from stranded dolphins available at the collection of the “Museo de Ballenas de Salinas,” (iii) 549 mtDNA control region (mtDNA CR) sequences from GenBank, and (iv) 66 concatenated sequences from 7-mtDNA regions (12S rRNA, 16S rRNA, NADH dehydrogenase subunit I–II, cytochrome oxidase I and II, cytochrome b, and CR) obtained from mitogenomes available in GenBank. Our analyses indicated population structure between both inner and outer estuary dolphin populations as well as with distinct populations of T. truncatus using mtDNA CR. Moreover, the inner estuary bottlenose dolphin (estuarine bottlenose dolphin) population exhibited lower levels of genetic diversity than the outer estuary dolphin population according to the mtDNA CR. Finally, the estuarine bottlenose dolphin population was genetically distinct from other T. truncatus populations based on mtDNA CR and 7-mtDNA regions. From these results, we suggest that the estuarine bottlenose dolphin population should be considered a distinct lineage. This dolphin population faces a variety of anthropogenic threats in this area; thus, we highlight its fragility and urge authorities to issue prompt management and conservation measures.

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SARS-CoV-2 reinfection is defined as a new infection with a different virus variant in an individual who has already recovered from a previous episode of COVID-19. The first case of reinfection in the world was described in August 2020, since then, reinfections have increased over time and their incidence has fluctuated with specific SARS-CoV-2 variant waves. Initially, reinfections were estimated to represent less than 1% of total COVID-19 infections. With the advent of the Omicron variant, reinfections became more frequent, representing up to 10% of cases (based on data from developed countries). The frequency of reinfections in Latin America has been scarcely reported. The current study shows that in Ecuador, the frequency of reinfections has increased 10-fold following the introduction of Omicron, after 22 months of surveillance in a single center of COVID-19 diagnostics. Suspected reinfections were identified retrospectively from a database of RT-qPCR-positive patients. Cases were confirmed by sequencing viral genomes from the first and second infections using the ONT MinION platform. Monthly surveillance showed that the main incidence peaks of reinfections were reached within four to five months, coinciding with the increase of COVID-19 cases in the country, suggesting that the emergence of reinfections is related to higher exposure to the virus during outbreaks. This study performed the longest monitoring of SARS-CoV-2 reinfections, showing an occurrence at regular intervals of 4-5 months and confirming a greater propensity of Omicron to cause reinfections.

Salmonella enterica is one of the most common causes of foodborne diseases. Bacteriophages provide an option to reduce the presence of Salmonella . Here, we describe the isolation of two lytic Salmonella bacteriophages. The complete genomes were annotated and show similarity to that of the lytic phage NBSal001, in the Drexlerviridae family.