What is the Oropouche virus (OROV)?
Oropouche virus (OROV) is not contagious; the arboviral disease is spread to humans by the bite of infected midges (small flies) and causes sloth fever. Midges attract carbon dioxide exhaled by humans. The spread of the Oropouche virus (OROV) throughout the world is an alarming situation. The Oropouche Virus is not considered contagious, and there is no evidence of direct human-to-human transfer of the Oropouche virus.
Arboviral disease
Infections from arboviral diseases occur when humans get exposed to viruses which spread through arthropod insect transmission including mosquitoes, flies, midges and ticks. The diseases provide different symptomatology that ranges from moderate to extreme symptoms that involve fever with headache and muscle and joint pain and rash leading to neurologic complications that include encephalitis or hemorrhagic fever.
History of the Oropouche virus till now
In 1955, the Oropouche virus was discovered near the area of the Oropouche River present in Trinidad. The reason for calling it sloth fever is that in 1960, OROV was detected in sloth’s blood. Till now, about 5 million cases have been reported, but not a single death has occurred due to OROV. The origin of such viruses is an Amazonian region, like South and Central America. But
Oropouche Virus in 2024
In 2024, the Oropouche virus spread to America and Europe, too.In 2024, the spread started from two provinces, Santiago de Cuba and Cienfuegos. On 27 May 2024, 74 cases were reported in these areas. Within the first six months of 2024, about 8087 cases were reported in the American region, i.e., Bolivia, Brazil, Colombia, Cuba, and Peru with two deaths and five vertical transmission cases causing serious issues. In July, 19 cases were reported in the European region, which has a recent travel history to Cuba and Brazil. Cuba is a famous tourist attraction, which caused the spread of OROV.
Oropouche Virus in 2025
Medical reports show that the Oropouche virus maintains its spread across the Americas during early 2025. During 2025 medical professionals reported these principal figures for Oropouche virus cases:
- The Oropouche virus affected 3,678 people during epidemiological weeks 1 to 5 of 2025 mainly within the Brazilian states Espírito Santo, Rio de Janeiro and Minas Gerais.
- A Canadian resident contracted Oropouche virus from Cuba in 2025 after returning from the country.
- The four cases of Oropouche virus in Cuba during 2025 were detected in Pinar del Rio as well as Cienfuegos, Villa Clara and Ciego de Avila provinces.
- In 2025 Guyana recorded a single Oropouche virus infection which affected a 15-year-old girl who had not visited any other destination.
- Panama reported 79 confirmed Oropouche virus cases during EW 6 of 2025 and all these cases were restricted to Darien province.
- Two suspected Oropouche virus cases appeared in Peru during the year 2025.
- The numbers display the continuous Oropouche virus transmission throughout multiple nations across the Americas region throughout the year of 2025.
Causes of Oropouche virus spread
The Oropouche virus spread achieves transmission through these important factors.
- The virus uses biting midges and mosquitoes as main transmission vectors by which it passes after these insects consume virus-carrying animals. The vectors pass virus to humans by their biting behavior.
- Sloths together with non-human primates and birds preserve the Oropouche virus in forested areas where they function as natural virus reservoirs.
- The transmission risks have increased since climate change and deforestation combined to create conditions that benefit vector growth whereas they change habitats.
- A recent research shows the virus accomplished genetic reassortment which enhances its ability to replicate in mammalian cells while increasing transmission potential.
- The virus has learned to thrive in urban settings which resulted in new outbreaks appearing in distant urban zones separate from forests due to growing human contact with vectors.
- The transfer of the oropouche virus from the Amazonian region to non-Amazonian regions is due to deforestation and unplanned urbanization. Climate change also causes it to spread to other areas.
Symptoms of OROV
Sloth fever symptoms are similar to dengue symptoms. Symptoms of Sloth fever or Oropouche fever appear for a duration of 2 to 7 days starting from when first symptoms appeared to patients. The initial recovery of symptoms in up to 60% of patients leads to their recurrence days to weeks afterward but the symptoms usually weaken during this period. The symptoms of fatigue and weakness tend to continue for several weeks during the recovery period following an initial sickness. You may feel fever, confusion, neck stiffness, headaches, skin rash, photophobia, chills, and joint pains (Myalgia and Arthralgia). Some people may also observe nausea, diarrhoea, or vomiting. Only 4% of cases observe two serious neurological problems: meningitis and encephalitis.
Complications
Neurological Complications
1. Meningitis
The meninges is a three-layered membrane that covers the brain and spinal cord. Infection of such a membrane is called meningitis. Their quick treatment is necessary; otherwise, you can face serious problems like memory loss, coma, hearing loss, vision loss, etc. Effects vary depending on the damage.
2. Encephalitis
In encephalitis, brain tissues swell due to infection, which can lead to many problems, such as memory problems, hallucinations, sensitivity to light, and behavioral changes.
3. Meningoencephalitis
The brain along with its protective layers becomes inflamed in patients who develop both conditions known as meningoencephalitis.
The major symptoms include intense neck pain, stiff neck, dizziness, confusion and lethargy in addition to nausea and vomiting and uncontrolled eye movements called nystagmus.
Hemorrhagic Manifestations
Bleeding Symptoms include massive blood loss through the nose and mouth as well as gum bleeding and dark blood in stools called melena and heavy menstrual bleeding menorrhagia and the appearance of petechiae as small red and purple spots on the skin.
Vertical Transmission and Pregnancy Complications
Reports from current studies demonstrate the suspected vertical passage of OROV during pregnancy which leads to fetal loss and microcephaly as well as other birth defects between mother and fetus.
Other Complications
Some patients may need substantial time to recover as they experience weakness and feel unwell for a duration up to one month following symptom appearance. Unhealthy individuals face opportunity for fatal outcomes which some medical reports have documented.
Clinical care needs to focus on strict OROV infection monitoring and management because of high risk outcomes among susceptible groups.
Preventive Measures
Vector Control and Personal Protection
People should protect themselves by applying insect repellents that have DEET and IR3535 as well as icaridin from the EPA. You should check the repellent will effectively ward off both biting midges and mosquitoes.
The protection starts with checking into protective clothing consisting of long-sleeved shirts together with pants which help to block skin exposure. Wear clothes which have repellents applied to them for protection from insects.
Fine mesh screens with a 20×20 mesh should be fitted to windows and doors because they stop biting midges from getting inside homes.
Avoiding Insect Bites
One should stay inside when biting hours are most active particularly inside air-conditioned areas. A solution of fans directed outdoors will help you minimize the number of biting midges present. The use of mesh nets of small dimensions should be placed over beds to discourage insect biting.
Travel Precautions
People should review Oropouche virus reports in their destination country before organizing travel.
Utility of insect repellents should continue for three weeks after travel to lower the chance of transmitting the virus.
Sexual Transmission Prevention
The sexual transmission risk of Oropouche virus is unknown at this time so medical authorities recommend male patients who have been diagnosed to use condoms or have no sexual activity for six weeks at the earliest onset of symptoms.
Pregnancy Considerations
Pregnant women should not take non-necessary trips to regions with Oropouche virus outbreaks because mother-infant transmission presents substantial risks.
Additional Recommendations
The prevention of Oropouche virus transmission requires specific health education programs which focus on high-risk population groups.
The surveillance system for midges and mosquitoes needs additional strengthening to track and minimize their colonization.
Treatment
Symptomatic Relief
Antipyretic medications including acetaminophen function to decrease body temperature in patients.
Pain relief medications in the form of acetaminophen serve as over-the-counter remedies to control muscle and joint pain symptoms.
Keeping a balance of fluids remains vital because fever or vomiting or diarrhea symptoms present.
Rest and Recovery
When rest becomes possible this provides an opportunity for the immune system to effectively fight the virus.
Hospitalization and Monitoring
Hospitalization becomes necessary to monitor severe cases of the virus specifically when neurological complications develop since patients need intravenous fluids.
Please avoid aspirin and ibuprofen and take them only when your doctor recommends them. The Oropouche virus weakens your immune system, so you must boost it by eating healthy fruits and drinking juices.
Current Updates about the Vaccine
According to current updates about the Oropouche virus no vaccine exists for public use. Experts continue their work to create therapeutic solutions and vaccine developments for the Oropouche virus. Recent advancements include:
- Scientists identify antiviral targets by studying how the Oropouche virus replicates on a molecular level. Knowledge of this kind serves as the foundation needed to create effective vaccines and treatments.
- The Pan American Health Organization (PAHO) gathered experts who established research priorities focusing on Oropouche virus. Health professionals must first solve present gaps in research while establishing specific evidence-based approaches for upcoming research initiatives.
- The advancement against Oropouche virus has encountered various obstacles which include its high mutation frequency and diverse immune response patterns and delivery constraints of immunizations. Developing a cure requires the solution of these obstacles.
- The development of specific Oropouche virus vaccines is actively pursued although no approved solutions exist at present. A vaccine development would advance the control of outbreaks while stopping the spread of Oropouche virus.
Continued research focuses on better understanding Oropouche virus and developing prevention strategies even though no vaccines exist at present.
Frequently Asked Questions (FAQs)
How long does sloth fever last?
Symptoms of Sloth fever or Oropouche fever appear for a duration of 2 to 7 days starting from when first symptoms appeared to patients. The initial recovery of symptoms in up to 60% of patients leads to their recurrence days to weeks afterward but the symptoms usually weaken during this period. The symptoms of fatigue and weakness tend to continue for several weeks during the recovery period following an initial sickness.
Conclusion
This virus is not contagious and has a low death rate, but in some cases, it is quite difficult to handle the seriousness. It is spreading throughout the world very fast. Its symptoms are just like dengue and malaria. Vertical transmission also occurs in such fever. Many serious complications appear during pregnancy.
