This Tropical Virus Is Spreading Out of the Amazon to the US and Europe
Oropuche outbreak The virus has been causing outbreaks in the Amazon for decades, but historically the pathogen has rarely caused trouble in other parts of the world. But that appears to be changing. In 2024, the virus showed it could spread.
Most of the more than 11,000 cases this year have been in Brazil and Peru, where the virus is an old familiar, but it was also detected in Bolivia, Colombia, Ecuador, Guyana, Panama and Cuba in 2024, the latter 603 cases were reported as well as the first domestic transmission. Infected travelers have also spread the virus to North America and Europe: the virus has been detected twice this year in Canada and 94 times in the United States, with 90 cases reported in Florida and 30 in Spain, Italy and Germany. imported cases.
For those who study Oropouche virus and other arboviruses (a family of viruses spread by arthropods such as mosquitoes and ticks), the situation is worrisome. Although there are clues about its transmission cycle, there is not enough information to accurately predict Oropucci’s future behavior. “We have some pieces of the puzzle, but we cannot completely determine what role each piece plays,” said Juan Carlos Navarro, research director at SEK International University and head of the Emerging Diseases and Epidemiology Group. Role.
The first symptoms of the disease appear suddenly 3 to 12 days after the bite and usually last 4 to 6 days. Symptoms include headache, muscle and joint pain, chills, nausea, vomiting and light sensitivity. A rash and bleeding from the gums or nose may occur, and in severe cases, meningitis or encephalitis (inflammation of the brain and its membranes) may occur. Oropouche infections are usually uncomplicated, if unpleasant, but Brazil has recorded two virus-related deaths for the first time this year.
Where cases are occurring, researchers are increasingly identifying factors that may explain why the virus appears and spreads: deforestation. Navarro said the conversion of natural land to grow crops, drill for oil or extract resources “appears to be the main driver” of the outbreak. “It brings together three links: the virus, the vector and the human.”
natural circulation with gaps
In 1955, a young charcoal maker fell ill after two weeks of working and sleeping in a forest near the Oropuche River in Trinidad and Tobago. He had a fever for three days. This is the first documented case of Oropouche virus disease. Since then, dozens of outbreaks have been reported, most in the Amazon basin.
Navarro has spent 30 years studying arboviruses such as dengue, equine encephalitis, Mayarovirus and, since 2016, Oropouche virus. It has two transmission cycles. In the jungle, reservoirs of Oropouche virus—those animals that allow the virus to continue spreading even if they are not sick themselves—are thought to be nonhuman primates, such as neotropical marmosets and capuchin monkeys, sloths , rodents and birds. The viruses were either isolated from these organisms or antibodies were found in their systems. In fact, the disease is also known as “sloth fever.” It’s unclear what role sloths and nonhuman primates play in the transmission cycle, Navarro said. “They may be amplifying the host” – meaning they may allow the virus to multiply rapidly and reach high concentrations in the body.
When a human epidemic occurs, a second transmission cycle occurs. In this case, humans are the amplifying hosts, and the virus is spread from person to person through blood-eating insects. The main vector for spreading pathogens from person to person is midges Paraku midge, It is the size of a pinhead and is found from Argentina to the United States. Some studies show that Culex and Aedes mosquitoes can also transmit Oropouche virus. In fact, the virus first isolated in Trinidad and Tobago came from Venezuelan cochineal, Another type of mosquito.
2024-12-20 19:05:48