Raccoon dogs may carry and transmit COVID-19–causing SARS-CoV-2 to humans, although critical differences in the enzyme that facilitates viral entry into the cell may make the jump unlikely, a study in PLOS Pathogens finds.

"The key to a coronavirus moving from one species to another is its spike protein's ability to bind to receptors on the cells of the new host," the authors noted.

University of Minnesota researchers probed the interaction between the spike protein of SARS-CoV-2 and angiotensin-converting enzyme 2 (ACE 2), which lets the virus enter the cell. Coronaviruses such as SARS-CoV-2 are known for their ability to jump species, the researchers said.

Raccoon dogs are small, burly, foxlike canines native to East Asia that are thought to have been a possible intermediary in the SARS-CoV-2 interspecies jump to humans, which led to the COVID-19 pandemic. The animals, along with palm civets, are also thought to have been involved in the spread of SARS-CoV-1, the virus that caused an outbreak of severe acute respiratory syndrome (SARS) in 2002-2003.

"Several species are under scrutiny as potential culprits, including bats, pangolins, and raccoon dogs," the authors wrote. "Raccoon dogs came under suspicion after their DNA was detected alongside SARS-CoV-2 genetic material in samples from the Huanan Seafood Market in Wuhan City [China], which is widely considered the pandemic's point of origin."

Could also affect other mammals

Biochemical analysis showed raccoon dog ACE 2 does allow SARS-CoV-2 to enter the cell, although not as effectively as human ACE 2. 

Structural comparisons highlighted differences in the virus-binding residues of raccoon dog ACE2 compared to human ACE2 …, explaining their varied effectiveness as receptors for SARS-CoV-2.

"Structural comparisons highlighted differences in the virus-binding residues of raccoon dog ACE2 compared to human ACE2 …, explaining their varied effectiveness as receptors for SARS-CoV-2," the researchers wrote. "These variations contribute to the species barrier that exists between raccoon dogs and humans regarding SARS-CoV-2 transmission."

The discovery sheds light on how SARS-CoV-2 may affect other mammals, as well. "Our research underscores the potential of raccoon dogs as SARS-CoV-2 carriers and identifies molecular barriers that affect the virus's ability to jump between species," they concluded.

A study of newly admitted patients at two hospitals in Michigan found that patients with severe functional dependence were more likely to harbor multidrug-resistant organisms (MDROs) on their hands and less likely to be able to clean them independently, researchers reported today in Infection Control & Hospital Epidemiology.

The secondary analysis of 399 general medicine patients enrolled over a 6-month period in 2017 was conducted by researchers at Michigan Medicine, who were using data collected through the Patient Hand Hygiene Project Initiative to assess the correlation between patient functional dependence and hand contamination with MDROs. They found that odds of any MDRO contamination were more than two-and-a-half times higher (odds ratio [OR], 2.63; 95% confidence interval [CI], 1.21 to 5.72) among the 56 patients considered severely dependent, which was defined as a score of 4 or higher on the Katz Activities of Daily Living (ADL) scale, compared with the 298 patients considered functionally independent. 

Higher risk of room contamination

Among the MDROs identified, severe dependence was associated with higher rates of hand contamination with methicillin-resistant Staphylococcus aureus (MRSA; OR, 3.78; 95% CI, 1.39 to 10.23) and vancomycin-resistant Enterococcus (OR, 5.55; 95% CI, 1.09 to 28.22) but not resistant gram-negative bacteria. Patients with feeding dependence had the highest odds of hand contamination with MDROs (OR 4.76; 95% CI, 1.54–14.71), followed by continence, dressing, and toileting.  

Analysis of high-touch surfaces in patient rooms also found that the risk of MRSA contamination was higher in the rooms of severely dependent patients (OR, 2.60; 95% CI, 1.16 to 5.82).

The study authors say the findings could help inform targeted hand hygiene initiatives.

"Targeting high-risk populations and developing personalized interventions based on patients' functionality is important," they wrote. "Future studies should develop and test such interventions that take into account a patient's ability to perform hand hygiene and across various healthcare settings."

• The US Food and Drug Administration (FDA) has pushed back its review of Moderna's respiratory syncytial virus (RSV) vaccine owing to administrative issues. According to a press release from Moderna, the FDA has informed Moderna that it is working to conclude the review by the end of May 2024. Moderna said the mRNA vaccine remains on track to be reviewed at the Center for Disease Control and Prevention's Advisory Committee on Immunization Practices at the end of June. The single-dose vaccine targets RSV in adults 60 and older. "The FDA has not informed Moderna of any issues related to vaccine safety, efficacy or quality," the company said in the release.
• Pharmaceutical giants Sanofi and Novavax have announced an exclusive licensing agreement to co-commercialize COVID-19 vaccines beginning in 2025 and jointly develop novel flu-COVID-19 combination vaccines. "With flu and COVID-19 hospital admission rates now closely mirroring each other, we have an opportunity to develop non-mRNA flu-COVID-19 combination vaccines offering patients both enhanced convenience and protection against two serious respiratory viruses," said Jean-Francois Toussaint, PhD, the global head of vaccine research and development at Sanofi, in a press release from that company. The co-exclusive license will allow the partnership to commercialize Novavax's current stand-alone adjuvanted COVID-19 vaccine and include a sole license to Novavax's adjuvanted COVID-19 vaccine for use in combination with Sanofi's flu vaccines, and a non-exclusive license to use Novavax's Matrix-M adjuvant (immune-booster) in vaccine products.
• The Global Polio Eradication Initiative confirmed two new polio cases this week, both caused by circulating vaccine-derived poliovirus type 2. Angola has its first polio case since 2022. Chad reported its second of the year. In 2023, Chad reported 55 cases.