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The Oropouche virus: why should we be worried?
Viruses can cause various human diseases; you may have heard of the coronavirus, influenza virus, human immunodeficiency virus (HIV), and others. You likely also know that certain insects transmit several diseases, such as dengue, Zika, chikungunya, etc. These viruses are known as arboviruses (Arthropod-borne viruses) and account for approximately 39% of all human pathogenic viruses identified to date.
In the current year, the Oropouche virus, discovered in Trinidad and Tobago in 1955, has received more attention since the number of infected persons has increased dramatically in South America countries such as Colombia, Brazil, Argentina, Peru, Ecuador, Bolivia, Panama, Venezuela, and others. In French Guiana, Oropouche was diagnosed in 43% of all dengue-like syndrom. Because of this, health organizations and the scientific community are worried, and other reasons are well-explained in a review article written by Konrad M Wesselmann, et al., 2024.
The Oropouche virus is transmitted mainly by the midge Culicoides paraensis, however, mosquitoes such as Culex quinquefasciatus have shown low transmission rates; and Aedes serratus, Coquillettidia venezuelensis, Psorophora cingulata, Haemagogus tropicalis, have been found naturally infected. People who develop Oropouche fever have symptoms similar to those with dengue fever and other arboviral diseases, including febrile illness, headache, arthralgia, myalgia, nausea, vomiting, chills, and photophobia.
One major difference between Oropouche and other viruses such as Dengue, Zika, and Chikungunya is their genome structure. The genome is the nucleic acid molecule that contains all the information needed for the biological functions of living organisms. The genomes of dengue and many other arboviruses are composed of only one chromosome (molecule of nucleic acid); however, the Oropouche virus genome has three chromosomes. The virus exhibits high mutation rates because when two different strains of the Oropouche virus, or a similar virus, infect the same cell, they can exchange genetic material. This exchange of chromosomes significantly increases variations in the genetic information, enhancing the virus’s ability to adapt to different conditions. An example of a virus with multiple chromosomes is the influenza virus, which has eight chromosomes. Its mutation rate is extremely high, requiring the development of a new vaccine each year to provide immunity against the emerging influenza virus.
Although no deaths have been reported because of this virus, the spreading speed and the increase in the number of cases in several countries have shown red flags. Furthermore, there is reduced knowledge about its vectors, diagnosis, and treatment. The mutation rates are alarming because they can facilitate adaptation to new vectors such as the major vector of arboviruses (dengue, zika, chikungunya, mayaro, etc. ) Aedes aegypti and Aedes albopictus, which are present in all the continents, including North America (Canada, United States of America, and Mexico), and Europe countries such as Italy and France.
Moreover, if the virus changes quickly, the immunity generated by humans will be obsolete against emerging new virus strains, which would cause recurrent infections every year, as happens with the influenza virus. Other factors that raise significant concerns about these kinds of diseases, such as climate change, may accelerate the distribution of vectors. Deforestation, illegal mining, and intensification of agriculture increase the risk of contracting this infection through sylvatic cycles. These are some reasons why this virus has turned on alarms worldwide and highlight the necessity of doing more research to understand and control this disease.
Link to the original post: Wesselmann, K.M., Postigo-Hidalgo, I., Pezzi, L., De Oliveira-Filho, E.F., Fischer, C., De Lamballerie, X., Drexler, J.F., 2024. Emergence of Oropouche fever in Latin America: a narrative review. The Lancet Infectious Diseases 24, e439–e452. https://doi.org/10.1016/S1473-3099(23)00740-5
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