Day: November 29, 2023

A mystery disease which has killed up to 17 people in Uganda has been confirmed as anthrax, health officials said. The outbreak striking Kyotera district has seen infected patients suffer rashes and swollen limbs before dying. As many as 40 are thought to have fallen ill in recent weeks. Africa Centres for Disease Control and Prevention (Africa CDC) earlier this week said anthrax had been ruled out, but local officials have now said tests found the bacterial infection typically infecting cows, sheep, and goats. A number of cattle have also died during the outbreak and victims are thought to have caught the infection by eating contaminated meat. Dr Edward Muwanga, Kyotera’s district health officer, told the Telegraph: “The disease has been confirmed as anthrax. So we now know what we’re dealing with. “People started falling ill in October and we think they contracted the anthrax from eating carcasses of dead cows because 25 cattle have died of the disease in this area.” Local media have put the death toll at up to 17. Dr Muwanga said it was at least 12. He said patients were stricken with blisters, fevers, and a swelling of limbs before dying. Flu-like symptoms, followed by black boils Pontiano Kalebu, the executive director of Uganda Virus Research Institute (UVRI) also said the mysterious disease had been confirmed in laboratory tests in Entebbe as anthrax. “Yes, tests were carried out here and anthrax was confirmed from the samples,” he said. Anthrax is caused by a spore-forming bacterium called Bacillus anthracis that typically affects ruminants such as cows, sheep, and goats. The bacteria produce extremely potent toxins which are responsible for the symptoms, causing a high lethality rate. Cattle and sheep can die quickly, but leave carcasses showing little sign of infection. In humans, symptoms begin with a flu-like illness, followed by respiratory difficulties. Direct contact with anthrax can cause raised boil-like lesions on the skin which develop a black centre. If you inhale anthrax spores, they can cause damage to the lungs, which is often fatal. The outbreak has caused alarm in the district. Ben Karyabwite, 34, a grocery shop owner near Kyotera town said he was worried for himself, his wife and two daughters. He said: “We have been hearing of people dying of a mysterious disease that attacks them and causes rashes on their bodies. “Because we were being told that no cure has been found for this disease, it really terrified me. I had told my wife to minimise all movement … to reduce chances of catching the disease. “Even me, I stopped socialising with friends or attending crowded places.” International and local health bodies are scaling up disease surveillance to spot new infections and outbreaks in Africa. The continent’s poor healthcare systems and its exposure to deadly pathogens that jump from animals to humans, such as Ebola and Marburg viruses, have made it a focus on pandemic prevention. Protect yourself and your family by learning more about Global Health Security

In 1897, a massive outbreak of Sekiri, or “red diarrhoea”, in Japan killed more than 20,000 people within six months. Epidemics of dysentery were common in 19th Century Japan and elsewhere, but had been documented since biblical times, with the Ancient Greek physician Hippocrates coining the term dysentery (bowel trouble) to describe the cramping rectal pain and bloody, mucus-containing diarrhoea it provoked. Shigella still causes between 28,000 and 64,000 deaths among children in lower-income countries every year. With a fatality rate of more than 20%, the fear provoked by such outbreaks was palpable. The Japanese bacteriologist Dr Kiyoshi Shiga described dysentery as “the most dreaded disease of children” due to its sudden and severe onset and high risk of death. But the 1897 outbreak marked a turning point in the centuries-old battle against this scourge. Drawing on the latest scientific techniques, Shiga managed to isolate and identify the causative micro-organism from the faeces of affected patients – bacteria we now know as Shigella. Today, antibiotics and improved sanitation have dramatically reduced the frequency of such bacillary (bacterial) dysentery, but Shigella still causes between 28,000 and 64,000 deaths among children in lower-income countries every year. In places where clean water and sanitation are lacking, repeated infections can also lead to stunted growth and impaired brain development, which could have a lasting impact on children’s long-term health and productivity. Scientists have been trying to develop vaccines against Shigella for more than 100 years. But with several candidates now in phase 2 and 3 trials, hope is mounting that an effective vaccine may finally be within reach. What is Shigellosis? Shigella belongs to a large family of bacteria called Enterobacteriaceae and is closely related to Escherichia coli. There are four main types: S. dysenteriae, S. boydii, S. flexneri and S. sonnei, each of which have multiple strains. They are spread through dirty hands, food or water contaminated by human faeces, or contaminated flies landing on food. Fewer than a hundred bacteria are needed to trigger an infection, which makes shigellosis – a variety of dysentery – extremely contagious, and people can continue to spread the bacteria for several weeks after they have recovered. Shigella is a major cause of moderate to severe diarrhoea worldwide, responsible for an estimated 80–165 million cases each year, mostly in low or middle-income countries (LMICs). It is also a major cause of diarrhoea among travellers and military personnel visiting these countries. Symptoms can be mild, but include watery and/or bloody diarrhoea, fever, stomach pain and the urge to pass stool even when the bowels are empty. These typically start one to three days after infection and last for around seven days. Although many people get better with fluids and rest, severe infections are treated with antibiotics, making antimicrobial resistance (AMR) a growing problem. This could make treatment increasingly complex and expensive: a systematic review of travel-associated Shigella infections found that the percentage of drug resistant infections increased from 19% in 1990–1999 to 65% in 2000–2009. A Shigella vaccine would help to counter this problem by reducing countries’ reliance on antibiotics to treat such infections; overuse of antibiotics is a major driver of AMR. We also have growing amounts of evidence linking Shigella to stunting and long-term disability, meaning a vaccine could bring potentially considerable economic and societal benefits in the long-term. Vaccine development The World Health Organization (WHO) has listed Shigella as a priority pathogen for the development of new vaccines, but despite decades of research, there is currently no widely licensed vaccine available. One issue has been the lack of a commercial incentive to develop such vaccines, as shigellosis predominantly affects LMICs that don’t necessarily have the money to fund the necessary research and development, or to commit to purchasing doses in advance. This market failure is a key reason why Gavi, the Vaccine Alliance, was established. Have you read? Another challenge has been that with approximately 50 different strains of Shigella in circulation, a vaccine against just one of them is unlikely to solve the problem, because people can be reinfected with a different strain. The development of multivalent vaccines – ones targeting multiple types and strains of Shigella – is therefore a priority. Researchers have estimated that a vaccine with antigens from S. sonnei, plus three strains of S. flexneri, could cover up to 75% of global strains – and perhaps as many as 93% – due to cross-reactivity between vaccine-generated antibodies and antigens from other related strains of Shigella. Vaccine candidates There are currently nine Shigella vaccine candidates in clinical trials. These include five protein or polysaccharide-based vaccines, which are designed to be injected into muscle, plus four oral vaccines that are based on either live attenuated (weakened) or inactivated (killed) bacteria. Some of these vaccines are designed to prevent other infections, such as enterotoxigenic E. Coli (ETEC) – a major cause of diarrhoeal disease and travellers’ diarrhoea in lower-income countries – as well as shigellosis. Such combination vaccines could be particularly attractive in the context of increasingly crowded and expensive immunisation schedules, as countries seek to weigh competing health priorities. Of particular interest are vaccine candidates being developed by GSK and a Swiss company called LimmaTech Biologics, both of which are currently in Phase 2 trials, and contain antigens from S. sonnei and plus three strains of S. flexneri. They are designed to be given as two or three doses. Otherwise the pipeline of vaccines is still very young, and a vaccine against Shigella is unlikely to be widely available until the early 2030s. However after almost a century of research, an effective vaccine against a leading cause of diarrhoeal deaths in children is within reach. Not only could such vaccines save millions of lives, but they could also help to counter the growing problem of antimicrobial resistance and a major cause of stunting in young children.

Key Takeaways Most people are potentially infectious with COVID-19 for 10 days. People are typically the most infectious the first five days after they are diagnosed. Antibodies to the virus can last for months after infection or vaccination. Emergency room visits for COVID-19 are increasing across the country, suggesting that cases of the virus are also on the rise. If you happen to contract COVID-19, it’s understandable to wonder how long COVID stays in your system, both in terms of infectiousness and protective antibodies. As with every illness, there is a range. But as a rule of thumb, here’s what you should know. How Long Are You Infectious? There is some variability in how long you’re infectious with COVID-19, Thomas Russo, MD, a professor and chief of infectious diseases at the University at Buffalo in New York, told Verywell. “Most people no longer have detectable infectious particles by day 10, but it can vary,” he said. The Centers for Disease Control and Prevention (CDC) has isolation information for people with COVID-19 that notes that patients are most likely infectious during the first five days after they test positive for COVID-19. However, the CDC’s recommendations also suggest that people wear a mask for up to 10 days after testing positive to avoid getting others sick. The CDC also said online that people who have severe COVID-19 may be infectious beyond 10 days and may need to isolate for up to 20 days. “If you’re immunocompromised, you could potentially be infectious for a much longer period of time—20 days vs. 10 days, as well,” Russo said. “Children tend to test positive longer,” William Schaffner, MD, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, told Verywell. How Long Do You Shed COVID-19? Viral shedding is a term used to describe how long a virus is still detected in your body after you get sick, Schaffner explained. When you “shed” a virus, you may be able to infect others. “Over time, the amount of virus you shed diminishes,” Schaffner said. Not all viral shedding will make someone else sick, especially if you shed at low levels. It’s unclear how viral shedding has changed during the pandemic, but there is data on how long it may last now. One study published in 2022 in the journal Emerging Infectious Diseases analyzed samples from patients who were infected with the Omicron variant between November 29 and December 18, 2021. (Subvariants of Omicron are currently circulating in the U.S.) The results showed patients shed the most virus between days two and five after their diagnosis. However, the researchers also noted that people with mild or asymptomatic COVID-19 cases still shed infectious virus six to nine days after they developed symptoms or were diagnosed, even when their symptoms stopped. “There are rare people who continue to shed virus for a more prolonged period of time—a month, for example,” Schaffner said. “But for all practical purposes, 10 days is a good rule.” How Long Do COVID-19 Antibodies Last? Data published in the journal The Lancet in February 2023 offers some insight on the duration of COVID antibodies—proteins made by the immune system in response to an infection or vaccination. For the study, researchers analyzed data from 65 studies from 19 countries and compared the risk of getting COVID-19 again in people who recently had the virus to those who hadn’t been infected. The researchers learned that having the Omicron variant of COVID-19 lowered the risk of being hospitalized and dying from a new infection by almost 89% for 10 months, thanks in part to protective antibodies left behind from infection. That duration of antibodies seems to have gotten stronger over the course of the pandemic. People who were previously infected with a variant other than Omicron were just 74% likely to be protected from getting infected again after a month. That number dropped to 36% after 10 months had passed since the initial infection. In the case of antibodies from vaccination, a study published in The New England Journal of Medicine found that most people receive at least six months of protection after getting the shot. “Measurable levels of antibodies do decrease over time,” Russo said. “The most durable protection is in people who have antibodies from vaccination and infection.” Factors such as age and individual immunity can also influence how long antibodies last in any given person, Schaffner said. “Older, frail people and those who are immunocompromised will have antibodies that wane more than a young person who is fit as a fiddle,” he said. “But this is not a black and white phenomenon.” What This Means For You Doctors say that most people with COVID-19 will no longer infect others after 10 days have passed since their diagnosis or start of symptoms. Many people are also protected from being reinfected with COVID-19 for six months. However, factors such as your individual immune system, your age, your health status, and the variant you were infected with, can all play a role. The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page. Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Centers for Disease Control and Prevention. COVID data tracker. Centers for Disease Control and Prevention. Isolation and precautions for people with COVID-19. Centers for Disease Control and Prevention. Ending isolation and precautions for people with COVID-19: interim guidance. Takahashi K, Ishikane M, Ujiie M, et al. Duration of infectious virus shedding by SARS-CoV-2 Omicron variant-infected vaccinees. Emerg Infect Dis. 2022;28(5):998-1001. doi:10.3201/eid2805.220197 COVID-19 Forecasting Team. Past SARS-CoV-2 infection protection against re-infection: a systematic review and meta-analysis. Lancet. 2023;401(10379):833-842. doi:10.1016/S0140-6736(22)02465-5 Doria-Rose N, Suthar MS, Makowski M, et al. Antibody persistence through 6 months after