Oropouche virus disease is increasing in South America, Central America, and the Caribbean, according to new health advisories issued by both the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) [1]. The rise in the oropouche arbovirus, which is transmitted to people by the bite of midges and some mosquitoes, shines a new spotlight on three other mosquito-borne arboviruses—Zika, dengue and chikungunya —which has led to large-scale outbreaks in recent years [2].
Defining arboviruses and why they are spreading
Arboviruses are viruses that are transmitted to a mammalian host by an arthropod vector (i.e., these viruses are arthropod-borne). There are 150 arboviruses known to cause human diseases, and a subset of these—primarily the ones spread by mosquitos—are rapidly emerging as global health threats [3].
Researchers attribute the increase in arbovirus infections to a variety of factors, including increased urbanization, global travel, and climate change [4]. The convergence of these factors is increasing mosquito-borne health threats, particularly in tropical and sub-tropical areas where approximately 3.9 billion people live [5]. In response, the WHO launched a Global Arbovirus Initiative, a strategic plan led by a coalition of partners focused on monitoring risk, pandemic prevention, preparedness, detection, and response [6].
Arbovirus infections can strain healthcare systems
Oropouche, Zika, dengue, and chikungunya can cause similar clinical symptoms. Typically, these symptoms are mild and can include fever, chills, headache, and joint pain [7]. Sometimes, an arbovirus infection progresses to more serious concerns. For instance:
- Infection with oropouche can result in meningitis, encephalitis, or bleeding [8].
- Zika virus infection can lead to severe neurological complications such as Guillain-Barre syndrome (GBS) in adults and congenital Zika syndrome (CZS) in fetuses [9].
- Severe dengue can result in life-threatening conditions such as respiratory distress, bleeding, plasma leakage, shock, and organ failure [10].
- Chikungunya can cause chronic chikungunya arthritis or severe joint pain that continues for months [11].
Because there is no specific treatment beyond proper patient management, arborvirus outbreaks can strain healthcare systems, particularly when patients require hospitalization for supportive care, such as respiratory support [12]. Additionally, as happened with the Zika outbreak in Brazil in 2015, significant healthcare burdens can endure long after an epidemic has ended [13].
Populations most vulnerable to arbovirus infections
Research has shown a higher risk of arboviral infection is associated with markers of lower socioeconomic position, such as lower education, income poverty, and low healthcare coverage [14]. In addition, some arboviral infections in pregnant women, most notably Zika, can lead to obstetrical complications, neonatal infection, long-term neurological disorders after birth, and fetal loss, although the real incidence of adverse fetal outcomes during pregnancy remains under-reported [15]. There is also a greater risk of complications or severe disease in older populations and those with comorbidities [16].
Arboviruses present diagnostic challenges
Early and accurate diagnosis of arbovirus infection is crucial to support proper patient management and adequate public health measures; however, since patients with oropouche, Zika, dengue, or chikungunya infections present with non-specific symptoms, it can be difficult for clinicians to make a diagnosis without diagnostic tools such as enzyme-linked immunosorbent assays (ELISAs), lateral flow assays (LFAs), and reverse transcriptase–polymerase chain reaction (RT-PCR) [17]. Of these, RT-PCR tests have high specificity and sensitivity and can be designed to detect and differentiate among arboviruses [18].
Advancements in arbovirus vaccine development
Novel arbovirus vaccines are in development. For instance, the TAK-003 dengue vaccine is showing promise with efficacy over five years against virologically confirmed dengue (61%) and against dengue-related hospitalizations (84%) [19]. A chikungunya vaccine (called IXCHIQ) is also newly available and recommended for some travelers at higher risk of exposure or at increased risk of severe disease [20,21].
Of course, vaccination development isn’t the only challenge; there are also hurdles to overcome when implementing vaccination strategies. For arboviruses, vaccine hesitancy and strict cold-chain requirements may impede bringing vaccinations to remote tropical regions. That is why, in addition to advocating for vaccine development, the WHO is working to reduce the habitats of all mosquito species as a means of vector control [22]. Public awareness campaigns have also been launched to educate people about how to protect themselves from viruses spread by mosquitoes [23].
The urgent need for effective surveillance globally
Detecting and tracking changes and trends in arboviruses such as oropouche, Zika, dengue and chikungunya can help identify increased incidence of infections, enable rapid public health responses, and assess the effectiveness of interventions. For example, the latest WHO guidelines specify that laboratory methods for oropouche surveillance include: 1) virological (direct) diagnostic methods by amplification of the virus genome or virus isolation (i.e., real-time or endpoint RT-PCR using specific oropouche primers and probes) and 2) serological (indirect) methods to detect antibodies produced against the virus [24]. Strengthening global surveillance is a critical component for tackling emerging arbovirus threats worldwide.
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- https://www.who.int/emergencies/disease-outbreak-news/item/2024-DON530, https://emergency.cdc.gov/han/2024/han00515.asp
- https://pubmed.ncbi.nlm.nih.gov/27833670/
- https://sma.org/southern-medical-journal/article/arboviruses-and-their-vectors/
- https://www.sciencedirect.com/science/article/pii/S1879625720300225
- https://www.who.int/initiatives/global-arbovirus-initiative
- https://www.who.int/news-room/events/detail/2022/03/31/default-calendar/global-arbovirus-initiative
- https://emergency.cdc.gov/han/2024/han00515.asp
- https://emergency.cdc.gov/han/2024/han00515.asp
- https://www.who.int/news-room/fact-sheets/detail/zika-virus
- https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue
- https://www.who.int/news-room/fact-sheets/detail/chikungunya
- https://www.ncbi.nlm.nih.gov/books/NBK560866/
- https://www.scielo.br/j/csc/a/qCtHVVXbNSBNn6xsZRMmPLJ/?lang=pt
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9014035/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10868105/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7102293/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10223626/
- https://www.who.int/publications/i/item/WHO-ZIKV_DENV-LAB-2022.1
- https://www.thelancet.com/journals/langlo/article/PIIS2214-109X(23)00590-9
- https://www.cdc.gov/chikungunya/prevention/chikungunya-vaccine.html
- https://www.ema.europa.eu/en/news/first-vaccine-protect-adults-chikungunya
- https://www.who.int/news/item/11-04-2022-genuine-intersectoral-collaboration-is-needed-to-achieve-better-progress-in-vector-control
- https://www.cdc.gov/vector-borne-diseases/what-cdc-is-doing/prevent-detect-and-respond.html
- https://www.paho.org/en/documents/guidelines-detection-and-surveillance-emerging-arboviruses-context-circulation-other