Category: Infection

Introduction Bacterial resistance has emerged as a significant challenge in the field of global public health. Klebsiella pneumoniae (KP) is an opportunistic pathogen and one of the common causative agents of community-acquired and healthcare-associated infections. Carbapenem antibiotics are often the drug of last resort when controlling KP infections, but due to widespread use in recent years, CRKP have gradually emerged and become widely prevalent. Compared with carbapenem-sensitive Klebsiella pneumoniae (CSKP), CRKP has garnered more attention from the international community due to its rapid spread and limited treatment options. A multinational prospective cohort study conducted by Wang et al revealed that the 30-day all-cause mortality rate for healthcare-associated CRKP infections is estimated to be 34%, although the characteristics of CRKP infections epidemics vary across regions.1 Genome sequence analysis of 21,016 CRKP strains in 105 countries from 1980 to 2022 in the National Center for Biotechnology Information GenBank database by Yu-Ye Wu et al showed that worldwide, the prevalence of CRKP has progressed from 0.50% prior to 2010 to 31.43% in 2019, and that 51–68% of CRKP strains carry high virulence genes and urgently require increased clinical attention.2 Moreover, according to the 2023 data report from the China Bacterial Resistance Monitoring Network (CHINET), the resistance rates of KP to imipenem and meropenem have escalated rapidly from 3.0% and 2.9% in 2005 to 29% and 30% in 2023.3 The top five provinces in China with the highest CRKP prevalence rates are Henan Province (61.8%), Shanxi Province (58.3%), Beijing City (55.7%), Zhejiang Province (53.3%), and Hebei Province (38%). Our institution, located in the second place, faces a severe situation regarding bacterial resistance. Although CRKP is increasingly becoming an important problem, the independent contribution of carbapenem resistance and other risk factors to the prediction of CRKP infections is unclear. A number of previous studies have examined risk factors for CRKP infections, but the results were mostly variable and did not lead to consistent conclusions.4–6 Moreover, many of the investigated studies had limited sample sizes or focused on an important department or population, which may confuse the correct perception of CRKP infections among clinical healthcare professionals. In fact, CRKP infections can be widely distributed among various populations. Therefore, a large-scale case-control study to elucidate the predictors of CRKP infections and produce a prediction tool is necessary, which has an important role in early proactive screening for CRKP infections and preventive control by healthcare workers. Materials and Methods Study Design The study was conducted at the 2700-bed Second Hospital of Shanxi Medical University, a regional general medical institution in China. The hospital is located in Taiyuan City, Shanxi Province, an underdeveloped region in central China, and is a Class IIIA general hospital. Patients with KP infections in this institution over a five-year period from January 2018 to January 2023 were included in this study, and the inclusion criteria were: laboratory test specimens were positive for KP and met the Centers for Disease Control and Prevention (CDC) criteria for healthcare-associated infections. Exclusion criteria were: information with missing key data; patients with co-infections with other bacterial infections; and strains identified by the laboratory as non-pathogenic (colonising bacteria). Also, the records of patients with recurrent infections we recorded only once. The following clinical data were collected from our hospital infection management system “Blue Dragonfly”: (1) the source of the specimen and the department that sent the specimen for examination; (2) the general characteristics of the patient: gender, age, and the duration of the current hospitalisation. (3) Main disease diagnosis: tumour, diabetes, cerebrovascular disease, renal failure, respiratory failure, trauma. (4) Exposure of this hospitalisation: admission to ICU, surgery, central venous catheterisation time, mechanical ventilation time, catheter retention time, days of fever, drain use, blood purification, paracentesis, chemotherapy. (5) Drugs used in this hospitalisation: immunosuppressants, carbapenems, aminoglycosides, cephalosporins, quinolones, tetracyclines, glycopeptides, and β-lactamase inhibitor combination preparations. Parameter Definition The following terms were defined prior to analysis: CRKP infections were defined as KP with a minimum inhibitory concentration of ≥2 mg/L for ertapenem, ≥4 mg/L for imipenem or meropenem, or containing the carbapenemase genes listed above, in accordance with the CLSI Guidelines (29th edition).7 Healthcare-associated infections: hospital-acquired infections in hospitalised patients, including infections acquired during hospitalisation and infections that occur after discharge from hospital acquired in hospital; but excluding infections that have started prior to admission or are in the incubation phase at the time of admission. Infections acquired by hospital staff within the hospital are also hospital-acquired infections.8 Bacterial colonization: a phenomenon in which microorganisms, such as bacteria, grow on a patient’s skin, gastrointestinal tract, respiratory tract, oral cavity, and reproductive tract but have not yet caused clinical manifestations of the associated infection.9 Identification and Drug Sensitivity Analysis of Pathogens The strains were identified and tested for drug sensitivity based on the VITEK-2 Compact fully automated microbial identification analyser and drug sensitivity analyser (Bio Merieux, France), and the criteria for judging the drug sensitivity results of ertapenem, imipenem, and meropenem were strictly in accordance with the criteria of the American Society for Clinical and Laboratory Standardization (CLSI), and any one of the following criteria was satisfied: minimum inhibitory concentration (MIC) ≥4 μg/mL for imipenem, MIC ≥4 μg/mL for meropenem, and MIC ≥2 μg/mL for ertapenem.7 (The results of drug sensitivity tests were provided by the Microbiology Laboratory of the Second Hospital of Shanxi Medical University). Statistical Analysis Preliminary statistical analyses were conducted using SPSS 26.0 software. The Shapiro–Wilk normality test was used to determine the normality of the quantitative data. If the data followed a normal distribution, they were expressed as (x±s) and independent samples t-test were used for between-group comparisons. If the data were not normally distributed, they were expressed as M(P25, P75) and Wilcoxon rank-sum tests were used for between-group comparisons. Count data were described using frequency (%) and comparisons between groups were made using the Chi-square test or Fisher’s exact probability method. Statistical significance was considered at p<0.05. The analyses were visualized using R (4.3.1) software. The dataset was randomly selected 275 cases as the training set and

Children are mostly at high risk of contracting ear infections due to low immunity New Delhi: Bengaluru has seen a huge surge in viral fever over the last few months, and according to doctors It is causing a rise in ear infections too. Experts are now cautioning people to take care of their immunity levels, especially in the upcoming winter season. Even though usually the frequency of viral fever cases rises alarmingly during the weather-changing months, it is now seen affecting people throughout the year. Previously, ailments like respiratory syncytial virus or RSV, dengue, chikungunya, conjunctivitis, malaria, and stomach infections would see a rise only during monsoons, but now, they are all year round. According to doctors, children are mostly at high risk of contracting ear infections due to low immunity. Related News Previous Next ENT specialists in Bengaluru are now seeing at least 10-15 severe ear infection cases in OPDs daily. According to doctors, most children are suffering from adenoid hypertrophy and tonsillitis. What causes ear infections? According to studies, ear infection, which usually begins after a cold or any other upper respiratory infection, is caused by bacteria and viruses that travel into your middle ear through the eustachian tube. Once inside, the virus or bacteria can cause your eustachian tubes to swell. The swelling can cause the tube to become blocked, leading to poor eustachian tube function and infected fluid in your middle ear. Signs and symptoms of ear infection Also known as otitis media, ear infection causes signs and symptoms which include: Ear pain Loss of appetite Trouble in sleeping Fever Trouble in hearing A feeling of pressure in your ear. Yellow, brown, or white drainage from your ear Doctors advise not to place anything in your ear canal if you have drainage from your ear as it can cause damage to the eardrum. Doctors are also alerting parents to be watchful of early symptoms like cold cough or ear pain to avoid infection which may last for even a month. Complications caused by ear infections Even though most ear infections do not cause long-term issues, complications may happen if they become chronic or are not treated well. A few complications include: Hearing loss You may suffer temporary hearing loss or changes in your hearing with muffled or distorted sounds during an ear infection. Repeated or ongoing infections or damage to internal structures in your ear can cause more significant hearing loss. Delayed speech Children need to hear to learn language and develop speech, and with muffled hearing, it can significantly delay development. Torn eardrum According to experts, nearly 5-10 per cent of children with an ear infection develop a small tear in their eardrum. Often, the tear heals on its own but if it doesn’t, your child may need surgery. Spread of the infection Untreated infections can spread to many other areas, including the bone behind your ear, or the membranes surrounding your brain and spinal cord, causing meningitis, which can be fatal. Disclaimer: Tips and suggestions mentioned in the article are for general information purposes only and should not be construed as professional medical advice. Always consult your doctor or a dietician before starting any fitness programme or making any changes to your diet.

The first human case of a new strain of swine flu has been detected in the UK, and health officials are trying to determine the virus’s origin. On Monday, the UK Health Security Agency (UKHSA) verified that a person tested positive for Influenza A H1N2v, a distinct but similar virus to the flu viruses spreading in pigs across the country. According to preliminary data, the H1N2 infection in the UK is genetically unique from other recent human cases globally, specified by its clade or form, 1b.1.1. “We are working rapidly to trace close contacts and reduce any potential spread,” says UKHSA’s incident director, Meera Chand. “In accordance with established protocols, investigations are underway to learn how the individual acquired the infection and to assess whether there are any further associated cases.” Following the onset of respiratory symptoms, the patient’s doctor in North Yorkshire tested the patient for the flu on November 9 as part of standard nationwide flu surveillance. Genome sequencing and PCR testing later identified H1N2. Details about the patient’s age or general health haven’t been publicly released, but it is known that the patient had a mild illness and has fully recovered. Outbreaks of swine flu, a respiratory illness of pigs caused by type A flu viruses, occur frequently in pigs, and people occasionally get infected. Influenza viruses that typically circulate through populations of animals – such as birds, horses, or pigs – and which only sporadically infect humans are known as variant flu viruses. This is represented by a lower-case v at the end of the subtype’s hemagglutinin (H) and neuraminidase (N) protein descriptor. Human infections with Influenza A subtypes, H1N1v, H3N2v, and H1N2v, have been identified previously, with the CDC reporting this year’s first US human cases in August. Though H1N2v has never been found in humans in the UK before, the UKHSA says that since 2005, 50 human cases have been reported elsewhere around the world. Virologist Ian Brown from the UK’s Animal and Plant Health Agency explains in an expert reaction to the UKHSA report: “These viruses generally lack the ability to spread human to human and such events are usually explained by direct or indirect contact with pigs.” While swine flu viruses have the potential to inflict widespread illness in pig populations, they typically only result in a small number of their deaths. Infected pigs may show symptoms of respiratory illness, though these are often mild or not present at all. According to experts, this case does not warrant alarm, though further information regarding the strain is necessary to assess the risk. University of Glasgow molecular virologist Ed Hutchinson warns that influenza A viruses can occasionally establish themselves in new host species. “Human and animal influenza A viruses can ‘breed’ if they get into the same host, producing hybrid offspring that are well-adapted to growing in humans but which aren’t recognised by our immune responses to previous human influenza infections or vaccinations (a process called genetic shift),” he explains. “Because of this, it’s particularly important to monitor spillovers of influenza A viruses.” Strains of influenza A subtype H1N1 have been responsible for a number of outbreaks in recent history, including the 2009 swine flu pandemic. Human infections with the virus swiftly spread across the world within weeks. That particular strain – A(H1N1)pdm09 – is now making seasonal rounds in humans and is no longer called swine flu. It’s different from the viruses presently circulating in pigs. To limit the spread of flu viruses between pigs and humans, the CDC recommends hand-washing before and after contact with pigs, not eating or drinking around them, and avoiding contact with pigs showing signs of illness. Health authorities in the UK are following up close contacts of the confirmed case and advising what actions they should take. For anyone experiencing respiratory symptoms themselves, the UKHSA reiterates that anybody with such symptoms should avoid contact with others, especially those who are elderly or vulnerable due to existing medical conditions.

As a result of the global Covid trauma, when lots of people in China sneeze, the world shudders. So, news that China is experiencing a surge in respiratory child illnesses, including pneumonia, has understandably given the world the jitters. Reports from local media and the Program for Monitoring Emerging Diseases — a publicly available system run by the International Society for Infectious Diseases — have mentioned clusters of “undiagnosed pneumonia” in children’s hospitals in Beijing, Liaoning and other places in China. The World Health Organisation promptly asked Chinese authorities for lab test results and data on recent trends in the spread of respiratory illnesses. WHO officials conclude that common winter infections — rather than any new pathogens — are behind the spike in hospitalisations. And most experts are not unduly concerned about this rise in child illness, blaming it on greater susceptibility to familiar pathogens after several winter lockdowns. But there are wider fears over how China may respond to another rapidly spreading virus. Paul Hunter, a professor of medicine at University of East Anglia who specialises in investigating the causes of outbreaks of infectious diseases, told i he thinks the current surge in illness is unlikely to be due to a novel virus. “Early reports of “pulmonary nodules” on chest X-rays of young patients in China are “consistent with bacterial pneumonias that tend to follow flu infections,” he says. “As this is the first full winter that China has not had Covid restrictions in place, we are probably seeing high numbers of such infections as we did last winter… some sources are suggesting that current cases are not as high as some years pre-Covid.” Another researcher, Benjamin Cowling, an epidemiologist at the University of Hong Kong, has a similar take. He told Nature magazine: “This is a typical ‘winter surge’ in acute respiratory infections. It is happening slightly earlier this year, perhaps because of increased population susceptibility to respiratory infections resulting from three years of Covid measures.” The question remains, however, would China react with any greater alacrity and transparency than it did in January 2020, when Covid began spreading through the population of Wuhan? And it’s a question with real urgency, given the prospect that another pandemic could occur at any time from any one of hundreds of wet markets, which appear as busy and popular as ever. Most China watchers doubt it. “The problem is, that Xi Jinping does not accept that China’s action or non-action was responsible for the Covid pandemic, so it’s hard to learn lessons when China could not have made any mistake,” says Professor Steve Tsang, the director of the Soas Chinese Institute in London. Many professionals in China, of course, want to perform their duties – just as the whistle-blowing medic Li Wenliang did at the start of the pandemic. He sounded the alarm about the emergence of deadly Sars-like illness in Wuhan, at the start of 2020. He died of Covid on 7 February after being told by officials to “stop making false comments” and was investigated for “spreading rumours”. The trouble is, says Professor Tsang, most medics and scientists feel obliged to follow the orders of the Chinese Communist Party, and “since China is under the rule of a strongman, it is about how one man, Xi Jinping, decides how things are to be done… No one dares to do anything that can be seen as suggesting China had done something wrong in the start of the Covid pandemic. “We better keep our fingers crossed that nothing like Covid emerges from China again any time soon.” Neither are scientists very optimistic that China has learnt its lesson. “Communication is key and, given the Covid experience, I would have hoped to see a more proactive, transparent and engaged response from China to new disease clusters, but that is unfortunately not what we’ve seen so far,” says Dr Fillipa Lentzos, a biothreats expert and a reader in science and international security at King’s College London. She was one of the two dozen scientists from the US, UK, France and Australia who called in an open letter in March 2021 for a fresh international inquiry into the origins of Covid pandemic. The open letter came after a team of WHO investigators announced it would scrap an interim report on the origins of the virus after its fact-seeking mission in Wuhan was consistently impeded by Chinese officials. Dr Lentzos and her co-authors said the WHO investigators had so little access to the resources they needed that it was “all but impossible” to confidently conclude that the virus did not escape from a Chinese laboratory. Most scientists working in the field believe Covid did occur naturally, as an animal virus crossing over to humans. But given the clinical importance of understanding how the viral infection arose in human populations, it was incumbent on Chinese authorities to be as open as possible. If another novel and deadly virus does arise in China, would the authorities alert the world more quickly than it did last time? Depressingly, the answer is: probably not.

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ByYamini C S Nov 29, 2023 09:48 AM IST Share Via Copy Link The Karnataka health department issued an advisory after a surge in respiratory illnesses in China, and prescribed guidelines to curb the spread of infection. As respiratory illnesses surge among children in China, the Karnataka health department on Tuesday issued an advisory to the public to take precautions and avoid diseases that are communicable through air. The department warned that infants, the elderly, pregnant women, the immunocompromised and those taking long-term medications are more at risk of infection. (For representation) “In view of the recent media reports of surge in respiratory illness among children in China and taking note of the WHO statement on these reported cases, the increase in respiratory illness among children is attributed to usual causes like Influenza, Mycoplasma pneumonia, SARS-CoV-2, etc and not due to any other unusual pathogen,” the department noted in the advisory. We’re now on WhatsApp. Click to join. Seasonal flu is an infectious disease that spreads from person to person through the cough or sneeze of a person with the flu, or through contact with droplets. This self-limiting disease lasts for 5-7 days and causes low morbidity and mortality, the advisory added. The department warned that infants, the elderly, pregnant women, the immunocompromised and those taking long-term medications, particularly steroids, are more at risk of infection and would require hospitalization. What are the symptoms of this Influenza-like respiratory illness? Fever Chills Malaise (a general feeling of discomfort) Loss of appetite Myalgia (pain in muscles) Nausea Sneezing Dry cough READ | ‘Don’t panic unnecessarily’: Karnataka health dept issues advisory after finding Zika virus near Bengaluru READ | Karnataka health dept issues guidelines over Nipah outbreak in Kerala. Details What are some do’s and dont’s for prevention and control? Cover your mouth and nose with a handkerchief or tissue when you cough or sneeze. Wash your hands often with soap and water. Avoid touching your eyes, nose or mouth unnecessarily. Avoid visiting crowded places and if visiting such places use a face mask. Maintain basic minimum distance from persons affected with flu. Sleep adequately, be physically active and deal with stress effectively. Drink plenty of water and eat nutritious food. Avoid spitting in public. Avoid travel to places with high incidence of Influenza and other respiratory illnesses. China Karnataka Government Health Influenza Virus Seasonal Influenza

Rajasthan, Karnataka, Gujarat, Uttarakhand and Tamil Nadu have asked hospitals and healthcare staff to ensure preparedness to tackle patients complaining of respiratory ailments. File Photo. Soon after the Centre’s directive to review preparedness in view of a surge in respiratory illnesses among children in China, five states have put their health infrastructure on alert mode. The state governments of Rajasthan, Karnataka, Gujarat, Uttarakhand and Tamil Nadu have asked hospitals and healthcare staff to ensure that they are adequately prepared to tackle patients complaining of respiratory ailments. The Karnataka health department has also asked people to be aware of the seasonal flu. Listing the symptoms and risk factors of seasonal flu, the advisory also mentions dos and don’ts. These include covering the mouth and nose while coughing or sneezing, frequent washing of hands, avoiding touching the face, and using masks in crowded spots. Rajasthan health department’s advisory indicated that the situation is “not worrisome at present” but the medical staff should keep watch and prevent spread of infectious diseases. It added that adequate arrangements should be made in paediatric units and medicine departments. Related Articles Australian envoy praises rescue of 41 tunnel workers in Uttarakhand After 10 days, first images of workers trapped in collapsed Uttarakhand tunnel emerge In Gujarat, health minister Rushikesh Patel said the healthcare infrastructure created during the COVID-19 pandemic was being strengthened as a precautionary step in view of the health crisis among children in China. The Gujarat government has asked government officials to review their readiness. In Uttarakhand, the government directed health officials to step up surveillance for cases of respiratory illnesses. Three districts of Uttarakhand — Chamoli, Uttarkashi and Pithoragarh — share borders with China. A statement by the state health department said that while the state hasn’t reported any child pneumonia cases yet, officials have been asked to keep watch as a precautionary measure. The move by the Uttarakhand government comes after the Union Health Ministry’s advisory to states, asking them to review preparedness to tackle any emerging situation. The Union Health Ministry has said the situation is not alarming, and it is closely monitoring it. “All States and Union Territories have been advised to implement ‘Operational Guidelines for Revised Surveillance Strategy in the context of COVID-19’, shared earlier this year, which provides for integrated surveillance of respiratory pathogens presenting as cases of influenza-like illness (ILI) and severe acute respiratory illness (SARI),” the ministry said in a statement. The sudden spike in respiratory illnesses in northern China, particularly among children, has become a cause for concern four years after Covid-19 emerged in the country and went on to become a pandemic that changed the world.

<!– –> States are reviewing their preparation following centre’s advisory on infections in China New Delhi: At least five states have put their health infrastructure on alert mode after the Centre’s directive to review readiness in view of a surge in respiratory illnesses among children in China. State governments in Rajasthan, Karnataka, Gujarat, Uttarakhand and Tamil Nadu have asked hospitals and healthcare staff to ensure preparedness to tackle patients complaining of respiratory issues. The Karnataka health department has also asked citizens to be aware of the seasonal flu. Listing the symptoms and risk factors of seasonal flu, the advisory also mentions dos and don’ts. These include covering the mouth and nose while coughing or sneezing, frequent washing of hands, avoiding touching the face, and using masks in crowded spots. The advisory issued by Rajasthan health department said the situation is “not worrisome at present” but the medical staff should keep vigil and prevent spread of infectious diseases. It added that adequate arrangements should be made in paediatric units and medicine departments. In Gujarat, Health Minister Rushikesh Patel said the healthcare infrastructure created during the COVID-19 pandemic was being strengthened as a precautionary measure in view of the China situation. The state government has asked government officials to review their readiness. The Uttarakhand government directed health officials to step up surveillance for cases of respiratory illnesses. Three districts of Uttarakhand — Chamoli, Uttarkashi and Pithoragarh — share borders with China. A statement by the state health department said that while the state hasn’t reported any child pneumonia cases yet, officials have been asked to keep vigil as a precautionary measure. This comes after the Union Health Ministry’s advisory to states, asking them to review preparedness to tackle any emerging situation. The Union Health Ministry has said the situation is not alarming, and it is closely monitoring it. “All States and Union Territories have been advised to implement ‘Operational Guidelines for Revised Surveillance Strategy in the context of COVID-19’, shared earlier this year, which provides for integrated surveillance of respiratory pathogens presenting as cases of influenza-like illness (ILI) and severe acute respiratory illness (SARI),” the ministry said in a statement. The surge in respiratory illnesses cases in northern China, particularly among children, has sparked concern four years after Covid-19 emerged in the country and went on to become a pandemic that changed the world. Chinese health authorities, however, have said the rising infections are a mix of already known viruses and are linked to the country’s first full cold season after strict Covid curbs were lifted last December, news agency AFP reported. Experts said that while the new situation remains unclear, there is little to suggest the cases were caused by a new virus.

Irish hospitals and GPs have noted a small increase in mycoplasma pneumoniae, a bacterium that causes lung infection and is a common cause of community-acquired pneumonia, peaking every three to seven years. The numbers in this country, which have risen in October and November, remain small. But in China, which is facing its first winter since the lifting of strict Covid restrictions, the infection is among a number of seasonal illnesses which have rebounded, including in children, whose immunity was damaged due to lack of exposure to bugs and viruses for so long. It causes lung infection and is a common cause of community-acquired pneumonia. Cases are more common in summer and early autumn, with peaks of disease every three to seven years, said the HSE. A spokesman said that currently the numbers of community cases identified diagnosed by the National Virus Laboratory are higher than those seen last year but it “as follows a cyclical pattern, it is to be expected.” Mycoplasma pneumoniae is not a notifiable disease in Ireland, similar to the vast majority of European countries, but outbreaks must be reported. So far this year a community outbreak of mycoplasma pneumoniae was notified to to the Health Protection Surveillance Centre in October – the first in a number of years. GPs who are part of a disease watchdog network reported back on six cases in October and nine this month – compared to one last year. Around one in two of these are in patients aged 15 to 64 years, 42pc were aged 5 to 14 years and 5pc of the cases are in children aged four and younger. Another 13 cases, mostly from hospitals, were notified this year so far versus no cases in 2022 and 2021. But there were 77 in 2020. The HSE stressed that the numbers are still very low. China , which was requested to provide a report to the World Health Organisation (WHO) last week on the sweep of respiratory illness hitting parts of the country, said it mirrored the surge seen in Europe last year due to the opening up after Covid restrictions and the increase in vulnerability of people to common infections. Meanwhile, UK reported a first confirmed case there of A(H1N2)v , a form of swine flu. It caused a mild illness and the patient has fully recovered.Around 50 cases have been reported globally in 20 years, A spokesman for HSE confirmed yesterday no cases of this strain of swine flu has been detected here. People in close, regular contact with pigs, poultry or water fowl should beware of flu symptoms and stay at home if they have them. Avoid contact with risk groups for flu and contact a GP if symptoms worsen. Cover coughs and sneezes and wash hands with soap and water or clean hands with alcohol-based hand gel. Vaccination remains the best protection against influenza and is recommended for people who have close contact with pigs, poultry and water fowl.

Some viruses move between species. For example, SARS-CoV-2, the virus that causes COVID-19, can spill over from humans to mink, an agricultural species, and then spill back from mink to humans. Spill back is a concern because SARS-CoV-2 can mutate in the mink and come back to humans in a more virulent form. Both spill over and spill back of SARS-CoV-2 have been reported on mink farms in the United States and Europe. To address these issues, a research team at the University of California, Riverside, has now studied zoonosis — the interspecies transmission of pathogens — in mink and found that TMPRSS2, an enzyme critical for viral fusion entry of SARS-CoV-2 in humans, is not functional in mink. Left: Prue Talbot (left) is seen with Ann Song, Right: Ann Song. (UCR/Talbot Research Group) “We found mink lung cells are infected by the ‘endocytosis pathway,’ not the TMPRSS2 fusion pathway commonly observed in human cells,” said doctoral student Ann Song, first author of the research paper that appears in Frontiers in Microbiology. “Our findings show that SARS-CoV-2 entry is not the same in all mammals and emphasize the need for thorough investigations into viral entry mechanisms across different species.” Song explained that viral fusion occurs when the membrane of the virus fuses with the plasma membrane of the host cell during infection. She said endocytosis is an essential process in which cells engulf external materials in small vesicles formed from their plasma membranes. SARS-CoV-2 can be taken up by host cells via endocytosis, she said. “Our results show that the functional — or enzymatic — domain is missing in mink TMPRSS2,” she said. “We do not know why. We think the enzyme may have multiple functions. It can do something else in mink, but it does not play a role in SARS-CoV-2 fusion to host cells. As a result, targeting TMPRSS2 would not be helpful in preventing infection in mink. What is clear is that SARS-CoV-2 entry varies among different species and tissue types.” Song said zoonosis is a public health concern as dangerous mutated forms of the virus could be introduced into the human population through spillback. During the pandemic, hundreds of papers were published on COVID-19 in humans. Now that COVID-19 in humans is under better control, scientific attention is turning to zoonosis. Lead author Prue Talbot, a professor of the graduate division in the Department of Molecular, Cell and Systems Biology in whose lab Song works, said researchers should not underestimate the possibility of spillover and spillback of SARS-CoV-2 in other mammalian species. “Deadly mutants can emerge from spillover/spillback events,” Talbot said. “As another example, many herds of deer, which are hunted by humans, are infected with SARS-CoV-2 and are thus potential sources of spillback.” Talbot and Song were joined in the research by postdoctoral researcher Rattapol Phandthong. Next, the research team will work on the infectability of human embryos in pregnant women who have COVID-19. To achieve their results, the researchers conducted their experiments using lung epithelial cells from mink. The research was supported by the Tobacco-Related Disease Research Program of the University of California, California Institute for Regenerative Medicine, and UCR. The title of the paper is “Endocytosis inhibitors block SARS-CoV-2 pseudoparticle infection of mink lung epithelium.”