Day: July 5, 2024

Let’s all take a moment and show some gratitude to our immune systems—day in and day out, intricate molecular machines are at work protecting our bodies from the microbial milieu that we inhabit. One of the immune system’s most important constituents are T cells (named after a fascinating organ called the Thymus, where they mature), which are present throughout the body and coordinate immune responses against pathogens. T cells exist in a variety of types—from ‘helper’ CD4+ to ‘killer’ CD8+ cells—but many share a general mechanism of activation: they initially lie dormant before being activated by an immunological stimulus, fight off the threat, then return to the dormant state. This cycle of activation-deactivation is critical for our immune systems to remain nimble in response to infections while avoiding prolonged inflammation and damage to healthy tissue. However, decades of research have revealed another side to this coin: a phenomenon termed T cell exhaustion. Although the exact definition is still under debate, T cell exhaustion generally refers to a progressive loss of functionality in T cells which are persistently stimulated over long periods of time. Exhaustion is theorized to represent a fail-safe mechanism to prevent chronic, deleterious immune overactivation, but exhausted T cells are also implicated in the progression of chronic infections and various cancers, making this an important phenomenon to better understand. The Lund Lab in the Vaccine and Infectious Disease Division at Fred Hutch studies immune responses to viruses of public health concern. A recent study from the lab led by former lab members Drs. Veronica Davé, Laura Richert-Spuhler, and Tanvi Arkatkar asks an interesting question about T cell exhaustion after infection with herpes simplex virus 2 (HSV-2), a pernicious virus infecting roughly ten percent of people nationwide which poses significant quality of life and health risks. HSV-2 infection—which causes the disease known commonly as genital herpes—is characterized by long periods of viral latency punctuated by brief episodes of recurrence (‘flare-ups’) of painful sores. As Dr. Davé puts it, “When you read about immune activation and T cell exhaustion, it’s usually grouped into two bins: acute activation (which happens when you get a vaccine or the flu) and chronic activation (which happens with a tumor, for example). We quickly realized that HSV-2 infection, with its brief bouts of acute immune activation and deactivation occurring over years-long time periods, doesn’t fit neatly into either of those bins, and presents an interesting opportunity to study how chronic viral reactivation impacts T cell health in the affected tissues.” To study the effects of chronic HSV-2 reactivation on T cells, the team made two important decisions: first, that they would primarily use samples from HSV-2 positive human patients rather than an animal model, and second, that a longitudinal study design (sampling the same HSV lesions in the same patients over time) would provide the most informative system to relate viral reactivation and subsequent immune involvement. Working with minute quantities of lesion biopsy tissue, Davé and colleagues used cutting-edge multi-parameter flow cytometry to sort and characterize lesion-associated immune cells based on a panel of cell surface markers. Here, she made the first interesting discovery: while viral recurrence leads to a sharp increase in total T cell abundance followed by a gradual return to baseline as lesions healed, the composition of the immune cell compartment (that is, the relative proportions of different T cell and other immune cell types) remained relatively unchanged throughout recurrence and even compared to adjacent, non-lesion tissue.

As of Wednesday, 12 July, no human contacts of A(H5N1) positive cats have reported any symptoms, the UN health agency said, adding that the surveillance period for all contacts has now complete. National first There have been previous “sporadic” cases of what is more commonly referred to as the bird flu virus, but the cases in Poland are the first time high numbers of infected cats have been reported over a wide geographical area within a single country, WHO said. “The risk of human infections following exposure to infected cats at the national level is assessed as low for the general population, and low to moderate for cat owners and those occupationally exposed to H5N1-infected cats, such as veterinarians, without the use of appropriate personal protective equipment”. WHO advised those exposed to animal flu viruses and all contacts of confirmed human cases, to monitor their health for the duration of the known exposure period, plus an additional minimum of seven days. ‘No change’ in WHO advice WHO said that the report of the infections among cats does not change its current recommendations on public health measures and surveillance. “Due to the constantly evolving nature of influenza viruses, WHO continues to stress the importance of global surveillance to detect and monitor virological, epidemiological and clinical changes associated with emerging or circulating influenza viruses that may affect human or animal health and timely virus-sharing for risk assessment,” the agency said. The UN agency called on public health and animal health authorities to collaborate closely, share information, and conduct joint risk assessment and response to outbreaks of zoonotic influenza at the human-animal interface, adhering to the One Health approach. Cat deaths According to WHO, as of 11 July, authorities in Poland tested 47 samples from 46 cats and one captive caracal wild cat. Of these, 29 were found to be positive for influenza A (H5N1). Fourteen cats were reportedly euthanized, and a further 11 died, with the last death reported on 30 June. The positive samples were reported from 13 geographical areas within the country. Source of exposure ‘unknown’ The source of exposure to the virus is currently unknown and epizootic investigations are ongoing. “There are several possibilities for the source of infection, among which the cats could have had direct or indirect contact with infected birds or their environments, ate infected birds, or ate food contaminated with the virus,” WHO said adding that, authorities are investigating “all potential sources and to date have not ruled out any.” Of the 25 cats for which information is available, two were outdoor, 18 were indoor with access to a balcony, terrace, or backyard, and five without access to the outside environment. Seven of the 25 cats reportedly had the opportunity for contact with wild birds. Ongoing monitoring WHO said that together with the UN Food and Agriculture Organization (FAO) and World Organisation for Animal Health (WOAH), it continues to monitor rapidly evolving virus, and updating recommendations for curbing its spread, in addition to working with countries in preparedness and response. The UN health agency is also evaluating the existing candidate vaccine viruses of A(H5N1) through its Global Influenza Surveillance and Response System to ensure valid candidate vaccine viruses are developed.

CONNECTICUT — The number of people who have been sickened by a parasite linked to different kinds of fresh produce has grown to 581 people in 31 states, including Connecticut, the Centers for Disease Control and Prevention said in a recent update of its investigation of the intestinal infection cyclosporiasis. The CDC and Connecticut health officials are monitoring intestinal infections caused by the parasite Cyclospora cayetanensis, which is typically spread by eating food or drinking water contaminated with feces. Cyclosporiasis cases are monitored by federal health officials to detect outbreaks that may be linked to a common food source. The illness can cause frequent and, at times, explosive bowel movements, stomach cramps, increased gas, nausea and fatigue. Flu-like symptoms, including vomiting, headache, body aches and fever, often accompany the infection. The CDC said in an update last week that the 581 illnesses have resulted in 55 hospitalizations. That’s an increase from 371 cases since the last update on June 22. Between 1-10 of those cases have been reported in Connecticut. See also: Teen, 16, and 20-Year-Old Killed In Crash The federal health agency said it has not yet identified the specific source of the outbreak, but said state and local health officials are interviewing people who have had illnesses to find out what foods they ate before they got sick. Illnesses are reported all year, but health officials often note increased cases during the spring and summer. Reports tend to increase starting in May, but this year, cases began to spike in April. “It is too soon to tell if this timing indicates a change in the seasonality of cyclosporiasis in the United States,” the investigation notice says. While the illness’ cause can vary, previous outbreaks have been linked to fresh produce, including basil, cilantro, mesclun lettuce, raspberries, and snow peas. Earlier this year, federal health officials investigated a spike of cyclosporiasis cases in Georgia and Alabama linked to raw broccoli that sickened 20 people. Officials determined the broccoli was imported. A cause for the remaining U.S. cases has not been identified and broccoli doesn’t appear to be the source, according to officials. To determine the cause, officials ask sick people what they ate in the 14 days before getting sick. If a common food is found, health officials will issue an advisory if the contaminated food is still available in stores or found in homes. Anyone infected with cyclosporiasis can experience symptoms for several weeks to a month or more. If untreated, symptoms may get better for a while and then return, and this pattern may repeat, health officials said. The illness is treated with antibiotics and the CDC advises health care providers to report any cases to the local health department.

ByHT Correspondent Jul 18, 2023 01:31 AM IST Share Via Copy Link Health minister Saurabh Bharadwaj said that the government is taking all precautions to ensure that vector-borne diseases are not spread in these camps Delhi health minister Saurabh Bharadwaj on Monday said that cases of conjunctivitis, skin allergies and fever are the most reported medical conditions in government flood relief camps. He added that the Delhi government is taking all precautions to ensure that vector-borne diseases are not spread in these camps. Many low-lying areas around the river were inundated and several families living in slum clusters along the Yamuna had to be shifted to relief camps after water entered their houses. (Vipin Kumar/HT) Also read: Yamuna water level see-saws, people in camps told to stay for now “Currently no cases of vector-borne diseases have been seen in the camps,” Bharadwaj said on Monday after visiting the flood relief camps in east Delhi. “Patients in the relief camps having symptoms of any disease will be admitted and monitored in the disaster management wards of hospitals,” he said, adding that it will also be known whether any new epidemic is spreading in the relief camps. Last week, water levels in the Yamuna started rising and hit a record-high of 208.66mm last Thursday. Many low-lying areas around the river were inundated and several families living in slum clusters along the Yamuna had to be shifted to relief camps after water entered their houses. Parts of east and northeast Delhi were the worst affected by the flooding. On Monday, Bhardwaj visited Swami Dayanand Hospital in east Delhi’s Shahdara and Lal Bahadur Shastri Hospital in Khichripur to take stock of the preparations in the hospitals. Topics Fever Delhi Health Minister

FDA (Adobe Stock, unknown) Today the FDA announced its approval of AstraZeneca’s monoclonal antibody, Beyfortus (nirsevimab-alip), for preventing respiratory syncytial virus (RSV) lower respiratory tract disease in neonates and infants entering or during their first RSV season and children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season. “RSV can cause serious disease in infants and some children and results in a large number of emergency department and physician office visits each year,” said John Farley, MD, MPH, director of the Office of Infectious Diseases in the FDA’s Center for Drug Evaluation and Research. “Today’s approval addresses the great need for products to help reduce the impact of RSV disease on children, families, and the health care system.” According to the press release, RSV is an often severe virus that causes respiratory infection in individuals of all ages. Infants and young children can develop severe lower respiratory tract diseases like pneumonia and bronchiolitis. Other patients are at higher risk, especially premature infants, those with chronic lung disease of prematurity or congenital heart disease, and older patients. According to the American Academy of Pediatrics, RSV hospitalizes approximately 1% to 3% of children under 12 months of age in the United States annually. As a monoclonal antibody with activity against RSV, it is a “laboratory-made protein that mimics the immune system’s ability to fight off harmful pathogens such as viruses. One dose of Beyfortus, administered as a single intramuscular injection before or during RSV season, may protect during the RSV season,” according to the press release. “RSV can cause serious disease in infants and some children and results in a large number of emergency department and physician office visits each year,” said John Farley, MD, MPH, director of the Office of Infectious Diseases in the FDA’s Center for Drug Evaluation and Research. “Today’s approval addresses the great need for products to help reduce the impact of RSV disease on children, families, and the health care system.” Three clinical trials (Trials 03, 04, and 05) supported the efficacy and safety of Beyfortus. Trial 03 enrolled 1,453 preterm infants born between 29 and 35 weeks of gestational age during their first RSV season. Beyfortus reduced medically attended RSV lower respiratory tract infection (MA RSV LRTI) risk by approximately 70% compared to the placebo. Trial 04 included 1,490 babies born at 35+ weeks. Of those included, 994 infants received Beyfortus, and 496 received a placebo. Beyfortus reduced the risk of MA RSV LRTI by approximately 75% compared to the placebo. Trial 05 tested Beyfortus on 925 at-risk infants up to 24 months old. The results showed it can prevent MA RSV LRTI in this population. The trial was a “randomized, double-blind, active (palivizumab)-controlled, multicenter trial, [that] supported the use of Beyfortus in children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season,” according to the press release. Beyfortus may cause rash and reactions at the injection site. It is important to note that infants and children who have experienced severe hypersensitivity reactions to the active ingredients or excipients in Beyfortus should avoid taking this medication. The press release noted that the Beyfortus received a Fast Track designation for this indication.