Taking Stock: Disease tsunamis
How U.S. farms could start a bird flu pandemic—Apoorva Mandavilli
The virus is poised to become a permanent presence in cattle, raising the odds of an eventual outbreak among people.
‘Without a sharp pivot in state and federal policies, the bird flu virus that has bedeviled American farms is likely to find a firm foothold among dairy cattle, scientists are warning.
‘And that means bird flu may soon pose a permanent threat to other animals and to people.
So far, this virus, H5N1, does not easily infect humans, and the risk to the public remains low. But the longer the virus circulates in cattle, the more chances it gains to acquire the mutations necessary to set off an influenza pandemic.
‘“I think the window is closing on our ability to contain the outbreak,” said Dr. Krutika Kuppalli, an infectious-disease physician who worked at the World Health Organization until April.
‘We’re so quick to blame China for what happened with SARS-CoV-2, but we’re not doing any better right now,’ she added. ‘That’s how pandemics happen.’
‘Half a year into the outbreak, H5N1 shows no signs of receding in U.S. dairy cattle or in the workers who tend them. In recent weeks, the virus has spread into poultry and workers.
‘As of Wednesday, infections had been reported in 192 herds of cattle in 13 states, and in 13 people. Nine were workers at poultry farms close to dairy farms in Colorado.
‘Earlier this month, the state reported that H5N1 had also been diagnosed in six domestic cats, including two indoor cats with no direct exposure to the virus.
‘Yet fundamental questions about the outbreak remain unanswered.
‘Researchers do not know how many farms are being investigated for the virus, how many cows are infected in each state, how and how often the virus jumps into people and other animals, what the course of the illness is in people and animals and whether cows can be infected more than once. . . .
‘In theory, nothing about this outbreak should make it difficult to contain, Dr. Van Kerkhove and other experts said. Unlike other influenza viruses, this version of H5N1 does not appear to spread efficiently through the respiratory pathway in cattle.
‘Instead, in most cases, infections seem to be transmitted through contaminated milk or viral particles on milking machines, vehicles or other objects, such as clothing of farmworkers. . . .
‘Federal officials have said findings like these undergird the belief that they can stop the virus. . . . But experts outside the government disagreed, saying the current measures were not enough to snuff out the outbreak. The virus is entrenched in wild birds, including waterfowl, and in a wide range of mammals, including house mice, cats and raccoons. . . .
Ideally, farms would ‘bulk test’ milk pooled from many cows at once and restrict movement of cattle and farmworkers until the virus was eradicated.
But federal rules require testing only when cattle are moved between states. And many states require testing only of cows that are visibly ill.
‘. . . Genetic data suggest that the U.S. outbreak stemmed from a single spillover of the virus from birds into cattle and then spread to other parts of the country. . . .
‘More likely, the virus will become enzootic—endemic or rooted in animals—much as other viruses have in pigs. Swine farms never rid themselves of a new virus, because susceptible piglets are constantly introduced into the population. . . .
‘The virus found in Colorado poultry farms appeared to have come from dairy cattle, and it resulted in the culling of 1.8 million birds. Nine workers involved in the slaughter became infected.
‘If this continues at this level, the dairy industry is going to sink the poultry industry,’ said Dr. Peacock.
‘. . . Most experts said it would be premature, and most likely unhelpful, to immunize farm workers with the current vaccines. But vaccinating cattle might be a workable option. . . .’
nytimes.com | @nytimes | @apoorva_nyc
Report highlights challenges of tackling antimicrobial resistance in Africa—Chris Dall
‘Amid a burgeoning mpox crisis, African health officials are drawing attention to the growing burden of antimicrobial resistance (AMR) on the continent and have laid out a roadmap for addressing the problem.
‘In the African Union Landmark AMR Report, launched last week, officials from the Africa Centres for Disease Control and Prevention (Africa CDC), the African Union Inter-African Bureau for Animal Resources, and member states reported that AMR was responsible for 255,000 deaths in Africa in 2019—more than 20% of the global total—and that sub-Saharan Africa experienced the highest AMR burden of any region in the world, with 27.3 deaths per 100,000 people.
‘Lack of antibiotics and diagnostics, overuse of antibiotics in people and food animals, suboptimal vaccination rates, significant gaps in AMR surveillance, and limited knowledge of AMR are some of the factors contributing to the problem, the report said. But officials said the issue is compounded by additional challenges, including lack of access to clean and safe water sources, inadequate infection prevention measures in hospital, and a shortage of funding and political will. . . .’
cidrap.umn.edu | @CIDRAP | @cvdall
How we lost control of mpox—Nature Briefing summary of Science article
’Science investigates the early history of mpox, the disease caused by the monkeypox virus. It has now infected nearly 100,000 people in 116 countries, particularly men who have sex with men. In 2017, infectious disease specialist Dimie Ogoina was the first to suspect that a series of mysterious cases in Nigeria indicated an emerging sexually transmitted infection (STI), but his work was discouraged by some in the scientific community. Stigma around STIs and homosexuality — Nigeria criminalizes same-sex sexual activity — and indifference from the Global North seem to be factors that helped the outbreak to grow.’
science.org | @ScienceMagazine | @Nature
+ The children bearing the brunt of the mpox outbreak—BBC
‘About 75% of the mpox cases being seen by medics in the eastern Congolese city of Goma are under the age of 10, a doctor has told the BBC. Across the region, internally displaced people are often crammed in camps without good sanitation, allowing the disease to run rampant.
+ Why mpox vaccines aren’t flowing to Africans in desperate need—New York Times
Drugmakers have supplies ready to ship that are necessary to stop a potential pandemic. But W.H.O. regulations have slowed access.
‘There are no vaccines for mpox available in the Democratic Republic of Congo, the epicenter of a global health emergency declared last week, even though the country first asked for the shots two years ago and the manufacturers say they have supplies.
‘So where are the shots? They are trapped in a byzantine drug regulatory process at the World Health Organization.
‘Three years after the last worldwide mpox outbreak, the W.H.O. still has neither officially approved the vaccines—although the United States and Europe have—nor has it issued an emergency use license that would speed access.
‘One of these two approvals is necessary for UNICEF and Gavi, the organization that helps facilitate immunizations in developing nations, to buy and distribute mpox vaccines in low-income countries like Congo.
‘While high-income nations rely on their own drug regulators, such as the Food and Drug Administration in the United States, many low- and middle-income countries depend on the W.H.O. to judge what vaccines and treatments are safe and effective, a process called prequalification.
‘But the organization is painfully risk-averse, concerned with a need to protect its trustworthiness and ill-prepared to act swiftly in emergencies . . . .
‘There have been more than 15,000 cases of mpox in Congo this year, and at least 550 deaths, although many cases are not diagnosed or treated. Most of those deaths have occurred among children, some of whom starve because agonizing lesions in their mouths and throats have prevented them from eating.
‘A new variant of the virus, spread by close intimate contact, has now crossed Congo’s eastern border into 13 countries, prompting the W.H.O. to declare a global health emergency on Aug. 14. . . .’
+ WHO launches plan to contain mpox—CIDRAP
‘The World Health Organization (WHO) today announced the launch of a preparedness strategy and response plan to contain a mpox outbreak rapidly spreading in African countries, with two related cases recently reported in Sweden and Thailand.
‘The plan, which covers the next 6 months, also includes a more fleshed-out price tag of $135 million, for which the WHO will soon launch a funding appeal.
‘In a speech today at a meeting of the WHO regional committee for Africa, WHO Director-General Tedros Adhanom Ghebreyesus, PhD, said the plan hinges on comprehensive surveillance and response, minimizing zoonotic transmission, empowering communities to take an active role, and advancing research on and equitable access to vaccines and other countermeasures. . . .’
Livestock virus hits Europe with a vengeance—Erik Stokstad (h/t Helga Recke)
Bluetongue spreads rapidly in sheep and cattle in six countries despite the use of three new vaccines
‘Bluetongue, a viral disease that sickens cattle and kills sheep, is spreading rapidly across northwestern Europe after it resurfaced in the Netherlands last year—and three newly developed vaccines appear unable to stop it. A highly virulent form of the disease, which is transmitted by biting insects, first exploded across Dutch farms and has since caused outbreaks in Germany, Belgium, France, Luxembourg, and Denmark. “This is going really fast now, despite vaccination,” says Piet van Rijn, a molecular virologist at Wageningen University & Research. Veterinary virologist Martin Beer of the Friedrich Loeffler Institute calls it “a kind of tsunami which is coming.”
‘Economic losses from the outbreak, caused by a strain of the bluetongue virus named BTV-3, have not yet been tallied but could run into the hundreds of millions of euros. The source of the responsible viral variant is unknown, but it seems clear that climate change has enabled it to overwinter more easily and spread quickly. “It’s not going to go away,” says Christie Mayo, a veterinary virologist at Colorado State University.
‘Bluetongue was first described in sheep in South Africa in the 18th century. The bluetongue virus (BTV) does not infect humans but sickens many ruminant livestock species, causing sheep the most harm. Symptoms include fever, swelling of the jaw and mouth, the eponymous blue tongues, hemorrhages, and abortions. More than 29 BTV strains occur around the world, most of them transmitted by Culicoides biting midges. In calm weather, these insects can fly several kilometers over a few days; with a stiff tail wind, they can travel hundreds of kilometers. Transport of sick animals may also help the virus spread.
‘Northwestern Europe never saw bluetongue until August 2006, when the Netherlands was hit by an outbreak of a strain named BTV-8. It spread wildly across Europe the next summer, but a new, highly effective vaccine ended the outbreak in 2008. Loss of livestock, testing, and vaccination cost about €200 million in the Netherlands alone.
In September 2023, a new BTV-3 variant of unknown origin turned up in the Netherlands and spread across the country in just 2 months.
‘Nearly 6000 Dutch farms were affected and tens of thousands of sheep died. Mortality rates were up to 75%, more than 10 times worse than during the BTV-8 outbreak. “It was a disaster,” says Margit Groenevelt, a veterinarian who teaches at Utrecht University and works for a company that provides care for about 20,000 sheep. “The impact on the farmers, it’s the worst I’ve ever dealt with in my veterinary career.” The outbreak paused when winter approached and most midges died after laying their eggs in the soil.
‘Three companies quickly began to develop vaccines for the insects’ return this year. All three contain killed copies of BTV-3 and an adjuvant to stimulate the immune system. Laboratory testing on small groups of healthy animals showed they offered good or complete protection from mortality, but not full prevention of infection and symptoms, Van Rijn says.
‘The first vaccine to reach the market, made by Syva, was given emergency approval in the Netherlands in April. In May, Dutch officials authorized two more vaccines, produced by Boehringer Ingelheim and CZ Vaccines.
‘In a preliminary report about the vaccines’ field efficacy released on 1 August, Dutch veterinary company and research organization Royal GD said mortality rates in immunized sheep on eight farms are “considerably lower” than the 75% seen last fall, and animals seem to be recovering in a few days. Sick dairy cows on two farms still have a “significant” decline in milk production, but only a few have become as seriously ill as last year, the report said.
‘Farmers have found the results disappointing, however. Many vaccinated sheep have fallen ill and some are dying. . . .
‘A spokesperson for Boehringer Ingelheim says the company has not received “any confirmed cases of lack of efficacy” and its vaccine “delivers what was expected: It does prevent clinical signs and mortality” if healthy animals are vaccinated at least 3 weeks before exposure. That’s a tricky task in the current situation, however.
‘Van Rijn and others have advised farmers to give sheep a second dose 4 to 5 weeks after the first to boost protection. But Groenevelt says many farmers have lost confidence in BTV-3 vaccines.
‘One way to increase the efficacy of this type of vaccine is to increase the amount of killed virus in each dose, says Stéphan Zientara, a virologist who directs the ANSES Laboratory for Animal Health—but doing so would raise the cost. Another approach is to search for BTV-3 variants that elicit a stronger immune reaction. . . .
‘A “big concern,” Van Rijn says, is that reassortment of BTV strains could lead to even more virulent pathogens. . . .
‘BTV-3 will probably continue to spread. . . . In the long term, Zientara says, BTV-3 may become less virulent, as happened with BTV-4 and BTV-8 in France. Until then, vaccination is key, Van Rijn says—despite its shortcomings. “We are with our backs to the wall, and we do our best with the vaccines we have.”’
science.org | @ScienceMagazine | @erikstokstad
Contaminated maize sparks fear in Zambia after 400 dogs die—Dingindaba Jonah Buyoya (h/t Lynn Brown)
‘Maize meal, or nshima, is Zambia's staple food
‘An "alarming number" of 400 dogs are thought to have died over the past month in Zambia after eating contaminated maize and humans could be at risk too, the country's health minister has said.
‘Elijah Muchima announced that approximately half of the 25 samples taken from milling companies were found to contain exceedingly high levels of aflatoxins, a poisonous substance produced by fungi. . . .
‘The World Health Organization (WHO) says there is evidence aflatoxins can cause liver cancer in humans. . . .
‘In their investigation, the authorities took samples from 10 milling companies that make maize-based dog food and also process the grain to make maize meal, which is consumed by humans.
‘The health ministry has not reported any human deaths resulting from contaminated maize. . . . Following the authorities' investigation, "affected batches" of maize meal have been recalled and seizure notices have been issued to "affected companies", Mr Muchima said. He did not name these companies or any specific maize meal brands. . . .
‘In his press briefing on Tuesday, Mr Muchima said climate change and the impact of Zambia's recent drought had "exacerbated the occurrence of aflatoxin this season".
‘Like much of southern Africa, Zambia was hit by a severe drought earlier this year. An estimated one million subsistence farmers experienced damaged crops and maize supplies in the country are still critically low.
‘Maize provides around 60% of the population's daily calorie intake, according to the US agriculture department, causing politicians and the public to worry about the contaminated batches. . . .’
bbc.com | @BBC | @BuyoyaJonah
Arresting headlines
Four billion people lack safe water: Water safety is a key challenge compounded by climate risks and data gaps—Science (h/t Helga Recke)
The veterinarians preventing the next pandemic: Most new diseases have their origins in animals. So why aren’t we paying more attention to their health?—The New Yorker
Largest genome sequenced so far is 30 times bigger than a human's: The South American lungfish has a whopping 180 gigabases of DNA in each cell, compared with 6 gigabases in human cells—New Scientist
Integrating qualitative methods into randomized evaluations—Abdul Latif Jameel Poverty Action Lab
Bird species are disappearing at an alarming rate in Kenya: new study—The Conversation