A study developed by Brazilian researchers during an Oropouche fever outbreak in the country in 2024 aims to assist in the diagnosis and differentiation of symptoms between this disease and dengue, especially in regions where they circulate together.
Titled Clinical and Laboratory Profiles of Oropouche Virus Disease in the 2024 Outbreak in Manaus, Brazilian Amazon, and published in the scientific journal PLOS Neglected Tropical Diseases, the study pointed out that the symptoms of Oropouche fever are very similar to those of dengue.
However, Maria Paula Mourão, a medical researcher at the Collaborative Network for Expanded and Timely Surveillance (Revisa), highlighted that the research identified some important differences between them, which are not always easily perceived by the clinical team.
“In Oropouche, headaches tend to be more intense, joint pains are more frequent, and skin rashes tend to be more widespread. We also observed more significant laboratory changes, such as a slight increase in liver enzymes, and differences in the immune system response,” said Maria Paula, in an interview with Agência Brasil.
“In dengue, there is usually a greater decrease in platelets, a higher risk of bleeding and shock. Even so, symptoms alone are not sufficient to safely differentiate one disease from the other,” she added.
According to the researcher, it is very difficult for the general population and also for health professionals to differentiate the two diseases based solely on the symptoms they cause.
Therefore, she emphasizes, the most important thing is not to make this differentiation, but to establish care and treatment that are effective against these symptoms.
“More important than knowing the name of the disease is to quickly recognize signs of severity, such as intense abdominal pain, persistent vomiting, bleeding, dizziness, mental confusion, or progressive worsening of the general condition, and seek the nearest health service,” she warned.
She added that pregnant women, children, the elderly, and people with chronic diseases need even more attentive care when they present with fever, even if the symptoms seem mild at first. “In these groups, the recommendation is to seek early medical evaluation and not wait for the condition to worsen.”
More virulent lineage
The work was conducted by a group of Brazilian researchers and is a result of the Expanded Health Surveillance Network (Revisa), organized with support from the Todos pela Saúde Institute (ItpS).
This study followed people with acute febrile illness who sought care at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), in Manaus (AM).
Patients were followed for up to 28 days, with clinical evaluation, laboratory tests, and specific tests for dengue, Oropouche, and other arboviruses.
During this work, the researchers also concluded that the outbreak that occurred in Manaus was caused by a reassorted lineage of Oropouche, already detected in previous years, but with characteristics of greater virulence and replication, which may explain the intensity and reach of the 2024 outbreak.
“We identified that the virus circulating in Manaus in 2024 belongs to a lineage that had already been circulating in Brazil, but which underwent genetic modifications over time. This suggests continuous local transmission.”
The researcher explained that these changes may have contributed to the intensity of the outbreak, but they are not the only factor—environmental, climatic issues, and the presence of the vector also play an important role.
Oropouche fever
Oropouche fever is caused by a virus that is mainly transmitted by the Culicoides paraensis mosquito, better known as maruim or gunpowder mosquito, found throughout the country.
After biting an infected person or animal, the virus remains in the insect for a few days. Then, when the insect bites a healthy person, it can infect them with the virus.
A researcher at the Todos pela Saúde Institute (ItpS), Bárbara Chaves explains that dengue and Oropouche fever are arboviruses, diseases caused by viruses transmitted by insects.
“Dengue is a disease well known to Brazilians, with which we have lived for many years. It has a high incidence in Brazil, mainly due to the abundance of the transmitting mosquito, Aedes aegypti. This is due to the favorable climate for mosquito proliferation and the urban characteristic of this species,” she emphasized.
Oropouche fever, the researcher recalled, became better known in the country starting in 2024, when it began to be reported in other Brazilian states as well.
“This spread and increase in the number of Oropouche fever cases may have occurred due to a combination of factors, such as changes in land use, including deforestation and agricultural development,” she clarified.
For Bárbara, reducing the number of cases of both diseases depends on improving diagnosis and monitoring.
“Regarding dengue, we can reduce incidence by combating the transmitting mosquito, that is, by eliminating breeding sites. There are also strategies already adopted in some cities, such as the Wolbachia method [technology that involves inserting the Wolbachia bacteria into some mosquitoes to prevent the viruses of these diseases from developing inside the mosquito], in addition to the vaccine against the virus,” she said.
However, in the case of Oropouche, control is a bit more complicated, since the mosquito that causes the disease reproduces in natural environments, humid and rich in decomposing organic matter.
“There are measures that can help to better understand and respond to these two diseases, such as monitoring the evolution of the viruses to identify different lineages and improving differential diagnosis between the two diseases, especially in regions where both viruses circulate.”
Source: brasil247.com