A mysterious pathogen: Oropouche virus more common in Latin America than previously thought

Charité - Universitätsmedizin Berlin

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Estimated basic risk of Oropouche virus infection in Latin America. In most at-risk regions, cases of Oropouche fever have been recorded either in the past or during the current outbreak. Although no official case reports have been recorded to date in some at-risk areas, environmental conditions could encourage an outbreak of the virus. © Charité | Anna Frühauf (image taken from the original publication in The Lancet Infectious Diseases)

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Credit: © Charité | Anna Frühauf (image taken from the original publication in The Lancet Infectious Diseases)

Like the dengue and Zika viruses, Oropouche virus causes a febrile illness. There are recent indications that infections during pregnancy can cause damage to unborn babies. Researchers at Charité – Universitätsmedizin Berlin have now determined that the virus is much more widespread in Latin America than previously assumed. Their study, published in The Lancet Infectious Diseases,* also suggests that climatic conditions have a significant influence on the virus’s spread.

Oropouche virus was identified in Latin America in the 1950s. In the decades since, official reports in most countries have been limited to just a few cases per year. An international research team under Prof. Jan Felix Drexler, head of the Virus Epidemiology laboratory at the Institute of Virology at Charité, has now undertaken an extensive study to examine the pathogen’s actual prevalence. “Our data shows that Oropouche virus is massively under-diagnosed in Latin America,” says Drexler, who also conducts research at the German Center for Infection Research (DZIF). “In some areas, at least one person in ten has experienced a prior infection with the pathogen.”

More widespread than thought – but still insufficiently investigated

Oropouche virus causes unspecific symptoms such as fever, chills, headache, pain in the limbs and, in some cases, nausea and skin rashes. For a long time, the disease was considered to be predominantly mild and reports of more severe bouts, including meningitis, were rare. For reasons that remain unknown, reported infections in Latin America and the Caribbean have soared beyond 20,000 cases since late 2023. Two deaths have been reported in young, healthy women and there are several cases in which an infection during pregnancy appears to have caused miscarriage or malformations in unborn babies.

“We still know relatively little about the virus,” explains Jan Felix Drexler. “The consequences of an infection, including on unborn babies, require further investigation. It’s not yet clear whether there are parallels with the Zika virus. Overall, however, it appears to cause harm to unborn babies less frequently than Zika.” There is no vaccine for Oropouche virus, nor is there a specific treatment for Oropouche fever.

In their study, the research team examined over 9,400 blood samples collected from healthy and diseased people in Bolivia, Brazil, Colombia, Costa Rica, Ecuador and Peru between 2001 and 2022. Antibodies against Oropouche virus – indicating a prior infection with the pathogen – were present in roughly 6% of samples across all territories. However, the researchers identified considerable regional variations: while antibodies against the virus were present in an average of 2% of samples from Costa Rica, they appeared in 5% of samples from Ecuador and over 10% of samples from the Amazon region. People at higher altitudes were less likely to have experienced a prior Oropouche infection than those at warmer, lower altitudes. A comparison of blood samples from different years also indicates fluctuations in infection rates from year to year.

Study estimates Oropouche infection risk for all Latin American countries

But what drives infections? In an effort to find out, researchers deployed machine learning techniques to analyze whether an association exists between Oropouche infections and various environmental and demographic factors. Their analysis found that climatic conditions, such as rain and constant temperatures, appear to exert the greatest influence on Oropouche virus infections. “We therefore assume that the current Oropouche outbreak has been fueled by weather phenomenons like El Niño,” explains Drexler. “By contrast, we have not found evidence that changing properties of the virus could provide an alternative explanation for the high case count at present. I think it’s possible that Oropouche virus will become even more widespread in the future as climate change progresses.”

Based on these insights, the research team estimated the Oropouche infection risk across Latin America, depicting this on an overview map. “The primary distribution area for Oropouche virus is the Amazon rainforest,” summarizes Drexler. “However, there is also a high risk of infection in parts of Central America and the Caribbean, as well as in southern and coastal areas of Brazil.”

Practical protection against infection

“Alongside the dengue and chikungunya viruses, Oropouche virus is probably most common virus transmitted by insect bites in Latin America,” emphasizes Drexler. He recommends taking systematic measures to prevent insect bites in order to protect against infection when visiting the region. “When it comes to protecting against Oropouche virus, and also against other tropical viruses like dengue and Zika, it’s worth wearing long clothes and using insect repellent, such as DEET or icaridin,” says the virologist. “Mosquito nets can also offer protection if their mesh is sufficiently fine.” The virus is primarily transmitted by flies commonly known as “no-see-ums” – tiny mosquitoes up to 3 millimeters long, which are able to pass through the mesh of conventional mosquito nets. Prof. Drexler recommends that pregnant women consult a doctor before spending time in at-risk regions for as long as the high infection rates persist, and until more is known about the effects of Oropouche on unborn babies.

*Fischer C, Frühauf A, Inchauste L et al. The spatio-temporal ecology of Oropouche virus: a laboratory-based modelling study across Latin America. Lancet Infect Dis 2025 Apr 14. doi: 10.1016/S1473-3099(25)00110-0

About the study
This research is part of the Zoonosis Emergence across Degraded and Restored Forest Ecosystems (ZOE) project, which receives funding from the European Commission through the Horizon Europe framework program, alongside support from many other funding organizations.

About Charité – Universitätsmedizin Berlin
Charité – Universitätsmedizin Berlin, a cutting-edge medical institution, is a leader in diagnosis and treatment of particularly severe, complex, and rare diseases and health conditions. A medical school and university medical center in one, Charité has earned an outstanding reputation worldwide, combining first-class patient care with excellence in research and innovation, state-of-the-art teaching, and high-quality training and education. At Charité, people and their health come first. Charité is dedicated to transformative translational research, applying the very latest scientific findings to prevention, diagnostics, and treatment and harnessing clinical observations to develop new lines of research and scientific questions. Charité’s foremost goal is to actively help shape the medicine of the future. https://www.charite.de/en/

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Journal

The Lancet Infectious Diseases

MISOGYNISTIC KULTURE

UC Berkeley analysis finds steep increase of self-harm among California girls, multiracial youth

While documented self-harm rates have increased across the board, researchers found multiracial girls, in particular, have seen incidences surge since 2016.

University of California - Berkeley

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There's been an approximately 75% increase in reports of multiracial teens treated for self-harm since 2016. 

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Credit: Credit Emily Liu et. al

The number of California teens who have been treated for self-harm has ballooned in recent years, with an especially concerning increase among multiracial girls, according to new research from the University of California, Berkeley, published today (Monday, April 14) in JAMA Pediatrics.

Using data from California emergency departments and inpatient care facilities from 2005 to 2021 — 231,232 reports in total — researchers examined both how the rate of annual nonfatal self-harm incidents has changed, as well as rate differences based on age, sex, and race and ethnicity.

The study found the overall self-harm rate among young people more than doubled, from 191 to 453 per 100,000 person-years — a public health metric used to track the incidence of disease or other life events. Researchers also found that nearly 73% of adolescents with treated self-harm injuries in California were girls.

White girls between 15 and 19 years old had the highest rate of self-harm in 2005 and have seen rates steadily increase since then. But multiracial adolescents have seen an increase of approximately 75% in self-harm rates since 2016. By 2021, self-harm rates were highest among multiracial teen girls, followed by those who are white.

Among boys, multiracial teens had the highest rates of self-harm and saw rates roughly double between 2016 and 2020. American Indian, white and Black boys saw rates increase, though not as dramatically.

"It's both the amount and also these increases that we're seeing over time that are most concerning," said Emily Liu, a Ph.D. candidate at UC Berkeley's School of Public Health and first author of the research.  

While prior work has found that girls are at higher risk of self-harm than boys, Liu's research shows incidences of self-harm are not universal across demographics.

"It's important to look at the data not just by sex, not just by age, not just by race or ethnicity, but by the intersection of all of these three things. It really does highlight the differences," Liu said. "The rates are rising, and we really need to pay attention to multiracial adolescents." 

Researchers expected a dip in self-harm cases treated at hospitals in 2020 and 2021, when people may have avoided health care facilities due to the raging COVID-19 pandemic. Yet, the incidences still rocketed up, according to the analysis. 

"If anything, it's a bit of an undercount for those two years," said Jennifer Ahern, a professor of epidemiology at UC Berkeley's School of Public Health and senior author of the research. "We know that this mental health crisis is not itself news. But self-harm injuries are very concrete physical manifestations of that crisis.” 

"This is really on the rise," she added, "and we would want clinicians to be prepared to help these children when they are appearing for care." 

Much has been written about what's driving the teen mental health crisis. Cell phones and social media are often seen as a main culprit, though researchers differ on how much blame devices and apps deserve. Better documentation practices at hospitals and a decrease in social stigma about seeking mental health help are also thought by some to have driven some of the increases in self-harm reports. 

Explaining what is driving the increase was beyond the scope of the new research, Liu said. 

Liu and her colleagues from UC Berkeley, New York University and the University of Minnesota conducted their analysis late last year and felt compelled to call attention to the work in a major journal as soon as possible. They announced their findings today as a relatively brief research letter, as opposed to waiting to publish a longer academic article, with the intent of drawing the attention of medical practitioners and those who work with adolescents. 

"This is an urgent issue that they need to pay attention to, "Liu said. "They should be prepared to be able to address health self-harm when it presents and also to think about ways to prevent it."

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Journal

JAMA Pediatrics

Method of Research

Data/statistical analysis

Article Title

Patterns of nonfatal self-harm among adolescents

Article Publication Date

14-Apr-2025

 

UH researcher unveils new model to evaluate impact of extreme events and natural hazards

Model tracks how pollution travels through Galveston Bay

Peer-Reviewed Publication

University of Houston

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Tracking how pollution travels, Hanadi Rifai, University of Houston Moores Professor of Civil and Environmental Engineering and director of the Hurricane Resilience Research Institute, has created a new model to evaluate the impact of extreme events and natural hazards.  
 

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Credit: University of Houston

When you’re on a sandy beach or the banks of a river, transformed by rolling waves or slightly still waters, it’s likely you’re not thinking about what happens just beneath the surface, where dirt and pollution are swirling and traveling through to new destinations.  

But Hanadi Rifai does. The Moores Professor of Civil and Environmental Engineering and director of the Hurricane Resilience Research Institute, has spent two decades examining Galveston Bay – its tides, currents and how fresh and salty water mix, continually extending the knowledge of predicting water levels, pollution spread and how ecosystems stay balanced. 

Now Rifai has created a sophisticated numerical computer model to help scientists and environmental experts understand how water moves in estuaries—places where fresh and saltwater mix. The model is the focus of an article in the journal Environmental Science and Pollution Research.  

“Models such as this one will be critical for evaluating climate variability and sea level fluctuation impacts on these lifeline systems for coastal communities,” reports Rifai, whose work will also guide better decisions to keep water clean, protect wildlife, and prevent flooding and pollution from spreading. 

Through the years Rifai has focused on emerging pollutants and pathogenic pollution and has conducted multiple sampling campaigns including sampling associated with hurricanes Ike and Harvey. She says the importance of taking samples over time and incorporating rainfall events and stream flows into predictive estuarine models cannot be overly emphasized. 

“An important lesson learned has been that the estuary while thriving and vibrant, is a complex system with many 'moving parts', and is sensitive to external influences that include extreme events (hurricanes, high winds, tidal fluctuations, extreme rainfall, drought, extreme heat, and industrial accidents and incidents),” said Rifai. “Historical uses have left their 'footprint' and continuing uses such as navigation, and recreation and municipal and industrial discharges are also associated with a 'trace'.” 

The analysis 

• Rainfall made water move faster, especially in the deep water 

• Where rivers met the estuary, water flow and speed were more unpredictable 

• Storms reduced salt but increased the amounts of suspended sediment in the water column (the surface to the bottom). 

• Rainy days also increased sediment, which supports the idea of sediment mobilization during storms. The latter causes redistribution of pollutants within the estuary. 

“The interactions between the water column and the underlying sediment and how to model those was a key focus in addition to evaluating the influence of extreme rainfall and hurricanes on identifying depositional versus erosional parts of the system,” said Rifai. 

Members of the team include Adithya Govindarajan, Gradient Corp., Boston, Martin Nguyen, a graduate student in the Rifai lab. 

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Journal

Environmental Science and Pollution Research

Article Title

Modeling water column dynamics in an urban estuary and their impacts on pollutant transport and system behavior

ECOCIDE

Illegal poisonings imperil European raptors and could disrupt ecosystem health

Raptor Research Foundation

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A Red Kite dead on top of her three eggs in the nest. Her mate  was found in distress on the ground and died shortly after. Both birds were confirmed poisoned with carbofuran.  

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Credit: Alan Ferguson.

A recent comprehensive assessment on the poisoning of raptors across Europe does not yield good news. This is according to the new paper “Poisoning in Europe Between 1996 and 2016: A Continental Assessment of the Most Affected Species and the Most Used Poisons,” published in the Journal of Raptor Research. A large team of raptor researchers amassed retrospective data on poisoning events across 22 European countries between 1996 and 2016. Carbofuran and aldicarb were the most common toxins reported and disproportionately affected scavenging raptors, especially in Northern Europe. As high-level participants in trophic interactions and providers of ecosystem services, raptors are crucial agents of Europe’s ecological health. These poisonings are, therefore, troubling. They are also illegal.

 

Poison is a well-known threat to raptor populations globally and every region has its star culprits: in the tropics, it’s veterinary drugs like diclofenac and the insecticide carbofuran. In temperate zones, rodenticides. In Europe, however, there hasn’t been a continent-wide assessment of illegal raptor poisoning events — until now.

 

Lead author Ralph Buij, from The Peregrine Fund, and 32 coauthors, invited raptor conservationists, toxicologists, and experts from wildlife forensic networks across the continent to submit their data on raptor poisoning events from 1996 and 2016. The team crunched the resulting dataset through multiple lenses including seasonality, species diet, whether poisonings resulted from single or multiple toxins, and whether poisoning occurrence changed over the course of the study period, including after European trade bans on relevant toxins.

 

Their results were sobering. A total of 3,196 poisoning events were reported, comprising 37 raptor species. Of these, six are Threatened according to the International Union for the Conservation of Nature’s 2024 status report, including the Saker Falcon (Falco cherrug). Four are Vulnerable, three are Near Threatened, including the Bearded Vulture (Gypaetus barbatus), and 15 have globally decreasing populations. The most commonly poisoned species overall was the Eurasian Buzzard (Buteo buteo), also Europe’s most common and widespread raptor. Carbofuran, aldicarb, parathion, and alpha-chloralose were the four most commonly detected poisons, the first three of which are pesticides that were banned by the European Union (EU) during the first half of the study’s timeframe.

 

Reasons for poisoning vary but include deliberate targeting of raptor species that are considered a threat to agricultural interests or game hunting. These poisonings usually occur through illegal placement of poisoned baits. Sometimes the baits are intended for other predators like foxes, yet result in raptor deaths through the scavenging process. Peak seasonality for reported poisoning events occurred in early spring, a result likely related to the timing of agricultural activities, game protection, and the onset of hunting efforts. Unfortunately, spring is the same season during which most raptors begin nesting activities. Raptors have long life spans, raise relatively few young, and don’t breed until later in life. All of these life history traits make deaths of breeding adults alarming from a demographic lens.

 

More than half of the carbofuran and aldicarb poisonings reported in this study occurred after the substances were banned from use in Europe, which points to a pervasive continent-wide issue of illegal application. In the Mediterranean, poisonings are thought to be responsible for more than half the total raptor mortalities and local extirpations. Taken as a snapshot, this underscores the role that poisoning can play in the death of raptors at various scales. Both Buij and coauthor Ngaio Richards are concerned by their assessment’s results. “I just keep wondering how much longer any of these populations can sustain such losses,” says Richards.

 

When asked what gives him hope about the future reduction of poisoning events, Buij says “where efforts have been increased to address the threats of poisoning, the results have been impressive.” Members of the team point to the LIFE Nature program of the EU as key for many projects and stakeholders in the fight against poisoning. They also laud Spain, which has implemented training of law enforcement officers and government experts, as well as a specialized Canine Unit to reduce poisoning events. “It really is a matter of committing resources to support not just a central system for data gathering,” says Buij, “but also anti-poaching and surveillance activities, enforcement and tougher penalties for the possession of poisons, and improved communications and awareness activities.” Richards adds that in her view, identifying potential or active poisoners within a community and enlisting them as allies can be more effective than employing exclusively punitive measures.

 

The authors encourage future focus on common and widespread species like the Eurasian Buzzard as early indicators of poisoning problems, as well as concentrated research on the ecosystem services provided by raptors across Europe as a way of documenting the tangible consequences of allowing this issue to persist. Raptors provide free, underappreciated services like removing rotting biomass and regulating prey populations. “I want to see more resources allocated to reviled species and to so-called common species which are currently the most visible face of poisoning,” says Richards. She also notes the importance of studying how poisons affect raptor prey. Collectively, the team emphasizes the need for more routine, standardized monitoring of poisonings for all raptor species across the continent, not just those that are endangered.

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Paper

Buij et al. (2025). Raptor Poisoning in Europe Between 1996 and 2016: A Continental Assessment of the Most Affected Species and the Most Used Poisons. Journal of Raptor Research, 59(2): 1-19.
DOI: 10.3356/jrr2373

Notes to Editor:

1. The Journal of Raptor Research (JRR) is an international scientific journal dedicated entirely to the dissemination of information about birds of prey. Established in 1967, JRR has published peer-reviewed research on raptor ecology, behavior, life history, conservation, and techniques. JRR is available quarterly to members in electronic and paper format. 

2. The Raptor Research Foundation (RRF) is the world’s largest professional society for raptor researchers and conservationists. Founded in 1966 as a non-profit organization, our primary goal is the accumulation and dissemination of scientific information about raptors. The Foundation organizes annual scientific conferences and provides competitive grants & awards for student researchers & conservationists. The Foundation also provides support & networking opportunities for students & early career raptor researchers. 

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Journal

Journal of Raptor Research

DOI

10.3356/jrr2373 

Method of Research

Data/statistical analysis

Subject of Research

Animals

Article Title

Raptor Poisoning in Europe Between 1996 and 2016: A Continental Assessment of the Most Affected Species and the Most Used Poisons

Carbofuran was banned in the EU in 2008. 

Credit

Irene Zorrilla.

Carbofuran granules in the gizzard of a poisoned White-tailed Sea Eagle, taken in a necropsy room in Berlin.

Adult White-tailed Sea eagle with typical yellow beak and white tail, taken in north Germany.

Credit

Oliver Krone.

Juvenile Peregrine Falcon poisoned with carbofuran at a quarry site in Northern Ireland, County Antrim.

 

Common Buzzard beside a carbofuran-poisoned rabbit bait in Northern Ireland. 

Credit

Marc Ruddock.