Beluga whale and bottlenose dolphin ACE2 proteins allow cell entry mediated by spike protein from three variants of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses infect numerous non-human species. Spillover of SARS-CoV-2 into novel animal reservoirs may present a danger to host individuals of these species, particularly worrisome in populations already endangered or threatened by extinction. In addition, emergence in new reservoirs could pose spillback threats to humans, especially in the form of virus variants that further mutate when infecting other animal hosts. Previous work suggests beluga whales (Delphinapterus leucas) and bottlenose dolphins (Tursiops truncatus) may be at risk owing to their formation of social groups, contact with humans, exposure to contaminated wastewater, and structure of their angiotensin-converting enzyme 2 (ACE2) proteins, which SARS-CoV-2 uses as a cellular receptor. We examined marine-mammal susceptibility to virus infection by challenging 293T cells expressing beluga or dolphin ACE2 with pseudovirions bearing the SARS-CoV-2 spike protein. Beluga and dolphin ACE2 were sufficient to allow cell entry by an early pandemic isolate (Wuhan-Hu-1) and two evolved variants (Delta B.1.617.2 and Omicron BA.1 strains). We conclude that SARS-CoV-2 poses a potential threat to marine mammal reservoirs that should be considered in surveillance efforts.

Alcohol loss arising from microbial contamination of drivers' blood specimens

This paper describes the circumstances in which some drivers' blood specimens containing added sodium fluoride (1% w/v concentration) deteriorated as a result of microbial contamination, accompanied by a decrease of alcohol concentration. Strains of the bacteria Serratia marcescens and a Pseudomonas sp. were isolated from the specimens and proven capable of growing at ambient temperature in blood containing sodium fluoride at 1% w/v concentration. They were shown to be active in alcohol degradation in preservatised blood, the activity being dependent on sodium fluoride concentration and storage temperature. Blood diluters were assumed to be a source of microbial cross contamination from one blood specimen to the next. It is recommended that postmortem blood specimens be analysed in separate batches from drivers' specimens when automated blood diluters are used, that the content of fluoride ions be increased to an equivalent of 2% w/v sodium fluoride, and that storage of specimens at temperatures above 4 degrees C be minimised.