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**Pathfinder** · October 16, 2024, 03:52 PM

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Oropouche fever: Brazilian outbreak could be linked to new version of virus

The current epidemic of Oropouche fever, a tropical disease that is particularly affecting Brazil, appears to be linked to the emergence of a new variant of the virus in question, according to...

By Afp
Published October 16, 2024 at 01:00
Updated October 16, 2024 at 05:00

The current epidemic of Oropouche fever, a tropical disease that is particularly affecting Brazil, appears to be linked to the emergence of a new variant of the virus in question, according to several studies, including one published on Wednesday.

The recent increase in cases "could be linked to a new recombinant Oropouche virus, with a greater capacity for replication," concludes this study published in the journal Lancet Infectious Diseases.

These findings are in line with similar work published in September in Nature Medicine and also carried out by researchers based in Brazil.

Since 2023, the country has been hit by an unprecedented epidemic of this disease, mainly transmitted by certain insects and with symptoms similar to dengue fever.

Although, like this one, Oropouche fever is generally not serious, it can cause serious complications, such as meningitis. For the first time, a few deaths linked to the disease were recorded this summer in Brazil.

Above all, the number of cases is unprecedented, with nearly 10,000 in 2024 alone in Brazil. Neighboring countries, such as Colombia and Peru, are also affected to a lesser extent.

Why such a surge? Both studies suggest that a new version of the virus is to blame. It reproduces faster and is more resistant to the immunity developed by people in these countries from previous infections.

To reach these conclusions, the researchers rely on both epidemiological data, around the circulation of the disease, and on in vitro observations, on the behavior of the virus taken from patients.

The new version of the virus is believed to be "recombinant", meaning that it arose from the joint infection of two different lineages of the virus in certain patients.

These conclusions must however be taken with caution, the Lancet Infectious Diseases study recalling in particular that previous Oropouche epidemics have been very little studied, which makes comparisons difficult.

Another study, published in the same journal, also suggests that the current epidemic has, for the first time, given rise to direct transmissions from mother to newborn, leading to malformations in the latter.

However, it is based on a very limited number of cases and does not allow firm conclusions to be drawn at this stage, with the authors calling for this transmission route to be explored further.

Fièvre d'Oropouche: l'épidémie brésilienne pourrait être liée à une nouvelle version du virus

https://www.notretemps.com/depeches/fievre-d-oropouche-l-epidemie-bresilienne-pourrait-etre-liee-a-une-nouvelle-version-du-virus-101151

L'épidémie actuelle de fièvre d'Oropouche, une maladie tropicale qui connaît notamment une flambée au Brésil, semble liée à l'apparition d'un nouveau variant du virus en cause, avancent plusieurs études, dont l'une publiée mercredi. La récente multiplication des cas "pourrait être liée...

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ARTICLES Online first October 15, 2024 Open Access

Re-emergence of Oropouche virus between 2023 and 2024 in Brazil: an observational epidemiological study

Gabriel C Scachetti, BSca,* ∙ Julia Forato, BSca,* ∙ Ingra M Claro, PhDb,* ∙ Xinyi Hua, DrPHb,* ∙ Bárbara B Salgado, PhDc,d,f,* ∙ Aline Vieira, MSca∙ et al. Show more
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Summary

Background

Oropouche virus is an arthropod-borne virus that has caused outbreaks of Oropouche fever in central and South America since the 1950s. This study investigates virological factors contributing to the re-emergence of Oropouche fever in Brazil between 2023 and 2024.
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Our analysis showed a higher incidence of Oropouche fever in 2024 within North Brazil, a historically endemic region with documented Oropouche virus circulation since the 1950s.1 This observation suggests that human populations in these areas continue to be exposed to Oropouche virus and might be susceptible to re-infection due to reduced neutralising antibody capacity against new epidemic Oropouche virus variants, such as the 2023–24 Oropouche virus reassortant. This hypothesis is based on the principle that previous Oropouche virus infection elicits a robust humoral response that can protect against homologous infection but not against novel reassortants, as previously described for Iquitos virus.8 This low level of protection is because the main target of the neutralising antibody response for orthobunyaviruses is the trimeric spikes in the glycoprotein encoded by the M segment,24 and consequently, change of this segment or mutations in the glycoprotein gene might lead to reduced neutralising capacity and binding of antibodies. Furthermore, the 2023–24 epidemiological and genomic surveillance data show a geographical expansion of Oropouche fever into previously non-endemic areas, including densely populated states in Brazil, such as Bahia, Piauí, Ceará, Espírito Santo, Minas Gerais, Rio de Janeiro, and Santa Catarina States.3 This spread emphasises the risk posed to the large, immunologically naive population across the Americas combined with the widespread availability of C paraensis and other potential Oropouche virus vectors from the southeastern USA to Uruguay.25 Consequently, the potential reduced neutralising antibody concentrations and putative increased viral fitness of the novel reassortant might contribute to re-infections in endemic areas, such as the Amazon basin, but also increase spread into new regions. For example, Cuba reported the first Oropouche fever cases between May and July, 2024, and a few cases were identified in Italy, Spain, Germany, and the USA among travellers returning from Cuba.2 This scenario could contribute to the introduction and establishment of Oropouche virus in the Americas and beyond, such as previously observed with dengue virus, Zika virus, and chikungunya virus.26
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Just a moment...

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(24)00619-4/fulltext

**Shiloh** · December 30, 2024, 04:14 PM

Source: https://en.mercopress.com/2024/12/30...ding-in-brazil

Another virus mosquito-transmitted disease, ‘oropouche,’ extending in Brazil
Monday, December 30th 2024 - 10:19 UTC

A new virus, oropouche, is extending in Brazil and has become of concern to the country’s Public Health Ministry, since it was circumscribed to the Amazon Region but has now been reported in at least 22 states and 11.000 cases during the first half of December.

Among the states involved are Espiritu Santo, neighboring with Rio do Janeiro, Rio Grande do Norte, Goias, the Federal District (Brasilia), and even to the southern areas of Parana and Rio Grande do Su, next to Argentina and Uruguay.

According to Brazilian health authorities, the country has been facing a significant increase of diseases caused by the arbovirus orthobunyavirus oropoucheense (OROV), and which is transmitted to humans mainly through the Culicoides paraensis mosqutoe, better known in Brazil as the “maruim” or “mosquito-pólvora”, The virus was first detected in Brazil in the sixties of the last century, following blood tests in labor working on the highway Belem/Brasilia...

**Shiloh** · December 30, 2024, 04:16 PM

Source: https://latinamericanpost.com/scienc...global-threat/

The Amazon’s Oropouche Virus Emerges as Global Threat
The Latin American Post Staff Send an email 7 hours ago

After the Oropouche virus stayed mainly in the Amazon basin for a long time, it has spread quickly across South America ‒ causing worry among scientists and health officials. As cases spread beyond Brazil and Peru into new areas, it creates a bigger problem for public health.
A Virus Spreads Beyond the Amazon

The Oropouche virus, an arbovirus transmitted by biting midges and mosquitoes, has circulated in the Amazon for decades. This year alone, there have been 11,634 cases, the majority in Brazil (9,563) and Peru (936). Previously concentrated in these countries, the virus has expanded its reach to Bolivia, Colombia, Ecuador, Guyana, Panama, and even Cuba, where its first endemic transmission resulted in 603 cases.

The virus’s geographic spread has crossed international borders, with infected travelers being reported in Canada and the Cayman Islands and 94 cases in the United States, mostly in Florida. Europe, too, documented its first 30 cases in Spain, Italy, and Germany. According to a report by Wired, this expansion is particularly concerning as the virus recorded its first fatalities and increased severe cases, including evidence of gestational transmission.

Juan Carlos Navarro, a professor at Universidad Internacional SEK, describes the situation as complex yet unsurprising. “We have some pieces of the puzzle, but there’s no certainty about the role each one plays,” Navarro told Wired. Despite decades of study, researchers lack sufficient data to reliably predict the virus’s behavior...

**Pathfinder** · March 4, 2025, 04:11 PM

Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
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Volume 31, Number 4—April 2025

Synopsis

Maternal and Fetal Implications of Oropouche Fever, Espírito Santo State, Brazil, 2024
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João Paulo Cola¹, Ana Paula Brioschi dos Santos¹, Raphael Lubiana Zanotti, Adriana Endlich da Silva Dela Costa, Karina Bertazo Del Carro, Lesliane de Amorim Lacerda Coelho, Angelica Espinosa Miranda², and Creuza Rachel Vicente²
Author affiliation: Secretaria de Estado da Saúde do Espírito Santo, Vitória, Brazil (J.P. Cola, A.P. Brioschi dos Santos, R. Lubiana Zanotti, A. Endlich da Silva Dela Costa, K. Bertazo Del Carro, L. de Amorim Lacerda Coelho); Universidade Federal do Espírito Santo, Programa de Pós-Graduação em Doenças Infecciosas, Vitória, Brazil (A.E. Miranda, C.R. Vicente)

Suggested citation for this article

Abstract

Reemergence of Oropouche fever in Brazil raises concerns about potential risks for infection in pregnancy. We describe a case series of Oropouche fever in pregnant women and their neonates in Espírito Santo State, Brazil, in 2024. Of 73 pregnancies, 15 pregnancies concluded by the end of the study period; of those, 14 resulted in live births and 1 in spontaneous abortion. Placental reverse transcription PCR tests were positive for Oropouche virus RNA in 5 infections in the third trimester. Two infections occurred in the first trimester, resulting in 1 spontaneous abortion and 1 live birth with corpus callosum dysgenesis. Of 13 infections that occurred in the third trimester, 1 showed possible intrapartum transmission with clinical manifestations in the neonate, whereas the others were asymptomatic. We found no anomalies in third-trimester infections. These findings suggest possible vertical transmission of Oropouche virus and a potential link with spontaneous abortion or malformation.

Oropouche fever is a vectorborne viral disease caused by Oropouche virus (OROV), an Orthobunyavirus primarily transmitted through the bite of the Culicoides paraensis midge (1). Endemic to tropical and subtropical regions of Central and South America, Oropouche fever is a reemerging public health concern with the potential for urban outbreaks and high attack rates (2). The disease typically manifests with a febrile syndrome characterized by headaches, myalgias, arthralgias, and occasionally neurologic manifestations, such as meningitis or encephalitis (3).

Arboviruses, such as Zika virus, dengue virus, chikungunya virus, yellow fever virus, and emerging and reemerging threats such as OROV, pose substantial risks during pregnancy, potentially leading to severe maternal and fetal outcomes, such as stillbirth (4). Although the effects of more established arboviruses are well-documented, such as congenital Zika syndrome, increased risk for hemorrhage with dengue, and preterm birth with chikungunya, as well as intrapartum transmission in dengue, chikungunya, and yellow fever (4–10), the effects of Oropouche fever during pregnancy remain less understood. However, the reports of stillbirth and congenital conditions and the virus’s neurotropic tendencies raise concerns about possible vertical transmission and fetal complications (6,10,11).

In addition to possible vertical transmission and adverse neonatal outcomes, pregnancy’s physiologic and immunological changes might increase the susceptibility of pregnant women to severe disease and complications (11,12). Those risks highlight the urgent need for research on Oropouche fever’s implications for maternal and neonatal health, alongside strengthened surveillance, vector control, and preventive measures such as mosquito and midge bite avoidance during pregnancy (13).

Oropouche fever is also a substantial concern in areas outside Brazil’s northwestern endemic area because of low population immunity (1). During a large outbreak in Espírito Santo, located on the coast of the southeast region of Brazil, we followed a series of cases of Oropouche fever in pregnant women to determine their clinical course and pregnancy outcomes.

Methods

We conducted a case series study describing the epidemiologic, clinical, laboratory, and obstetric outcomes of pregnant women diagnosed with Oropouche fever and their neonates. The cases included Oropouche fever in the Espírito Santo State’s residents reported during March 28–December 22, 2024. The study is in accordance with the Helsinki Declaration revised in 2013. It has the ethical approval of the Research Ethics Committee of the Health Science Center at the Federal University of Espírito Santo (approval no. 7,004,185). All data were anonymized to protect patient privacy.

We accessed the data through the e-SUS Health Surveillance System (e-SUS VS), the official system for compulsory disease reporting in Espírito Santo. The e-SUS VS system was developed in partnership with the Pan American Health Organization and implemented in January 2020. Laboratory surveillance for OROV in Espírito Santo began on March 25, 2024, after Brazil’s Ministry of Health provided reverse transcription PCR (RT-PCR) reagents to test samples negative for dengue, Zika, and chikungunya viruses at the Central Laboratory of Espírito Santo State (14). On April 23, 2024, the State Department of Health reported the first cases of Oropouche fever in the state (15). The protocol for managing Oropouche fever during pregnancy includes testing with RT-PCR in the following conditions: all pregnant women with suspected Oropouche fever; a neonate of a pregnant woman with confirmed or suspected Oropouche fever at the time of delivery; or cases of fetal death, stillbirth, and spontaneous abortion in pregnancies in women with confirmed or suspected Oropouche fever. For neonate cases, the test includes the placenta, umbilical cord fluid, and serum from the neonate and the mother, even if the neonate appears healthy. Cerebrospinal fluid is also tested in cases where the neonate shows neurologic complications (16).

The case series included pregnant women with a diagnosis of Oropouche fever on the basis of epidemiologic and clinical criteria and laboratory confirmation through RT-PCR. The RT-PCR for OROV was performed on serum samples collected up to 5 days after the onset of symptoms and placenta after delivery, following the protocol of Naveca et al. (17). We also included symptomatic pregnant women who were not tested for OROV infection but whose neonates were diagnosed with OROV infection through RT-PCR within 5 days of life. Epidemiologic and clinical criteria included those living in or visiting areas with active OROV transmissions and who had symptoms such as fever, headache, myalgia, back pain, arthralgia, retro-ocular pain, nausea, vomiting, petechiae, and exanthema (18). All neonates underwent a physical examination to identify any congenital abnormalities.

We collected data on maternal demographics and clinical characteristics, clinical manifestations of Oropouche fever, laboratory findings, and pregnancy outcomes, including type of delivery and complications such as preterm birth or spontaneous abortion. We also assessed neonatal outcomes, including birthweight and length, Apgar scores, and laboratory evidence of vertical transmission.

We described maternal age as mean + SD, medians and interquartile ranges, and categories divided by decades. Clinical characteristics included underlying conditions (e.g., diabetes and hypertension), week and trimester of illness onset (i.e., first, second, or third), and Oropouche fever clinical manifestations (e.g., fever, headache, myalgia, back pain, arthralgia, retro-ocular pain, nausea, vomiting, petechia, and exanthema). Regarding pregnancy outcomes, the types of delivery were cesarean section or vaginal birth and preterm birth (delivery at <37 weeks). Neonatal outcomes included low birthweight and length, considering the gestational age and Apgar score (reported categorically as 0–6 or 7–10) (19). Evidence of vertical transmission included OROV RNA identification by RT-PCR in the neonate biologic samples, such as serum. We summarized the results by absolute and relative frequencies.

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Results

A total of 4,062 cases of Oropouche fever were reported during March 28–December 22, 2024, in Espírito Santo, including in 73 pregnant women and their neonates. Of those, 71 women had OROV infection confirmed by RT-PCR during pregnancy; we included an additional 2 because their neonates had detectable RT-PCR for OROV RNA within 5 days of life.

Most pregnant women were 20–39 years of age (n = 67) and had OROV infection detected in the third trimester of pregnancy (n = 33). Hypertension (n = 6) and diabetes mellitus (n = 1), excluding gestational diabetes, were the only underlying conditions. Assessing whether the hypertension cases were related to chronic underlying hypertension or were pregnancy-induced was not possible. The most reported Oropouche fever manifestation was headache (n = 59), followed by fever (n = 55), myalgia (n = 52), retro-ocular pain (n = 32), nausea (n = 29), and back pain (n = 28) (Table 1).

Of the 73 pregnancies under observation, 15 had concluded by the end of the study period; 14 resulted in live births, and 1 resulted in spontaneous abortion. The remaining 58 pregnancies were ongoing, with patients continuing to receive monitoring. At the conclusion of this data collection period, no fetal anomalies had been reported in those cases.

In 1 case of spontaneous abortion (case 1), a pregnant woman without underlying conditions reported fever, headache, myalgia, back pain, retro-ocular pain, nausea, and arthralgia at 7 weeks of gestation; her serum sample tested positive for OROV RNA by RT-PCR. She sought hospital care at 8 weeks of pregnancy after experiencing vaginal bleeding. Imaging tests confirmed the spontaneous abortion (Table 2).

Among the 14 deliveries performed, most were cesarean sections (n = 10), with gestational ages >37 weeks (n = 14). The weight, length, and Apgar scores were adequate in all neonates (Table 3).

One pregnant woman (case 2) without underlying conditions had fever, headache, myalgia, nausea, and retro-ocular pain at 7 weeks of pregnancy and did not have laboratory confirmation of diagnosis for OROV or other arboviruses. At 32 weeks of gestation, ultrasound findings suggested dysgenesis of the corpus callosum body (truncus) on the right with dilation of the body of the lateral ventricle. At birth, through cesarean section at 40 weeks of gestation, cranial ultrasound findings confirmed dysgenesis of the corpus callosum. No other abnormalities were noted during the physical examination, and the neonate survived. The RT-PCR was positive for OROV RNA in the neonate’s serum sample 1 day after birth. No additional data on other imaging tests or ophthalmologic evaluations were available (Table 2).

Five of the pregnant women who underwent delivery had positive RT-PCR for OROV RNA in the placenta fragment, all of them with OROV infection in the third trimester of pregnancy. In 2 cases (cases 2 and 10), evidence of vertical transmission was found, and RT-PCR confirmed OROV RNA in the serum samples of the neonates (Table 2).

Possible intrapartum transmission during cesarean section was observed (case 10). In this case, spontaneous rupture of the membranes occurred 2 hours before the surgical delivery. A neonate returned to the hospital at 4 days of age, 1 day after the postpartum discharge, with fever; maculopapular rash in the torso, legs, and arms; and agitation. RT-PCR confirmed OROV RNA in a serum sample but was negative for dengue, Zika, chikungunya, Mayaro, and West Nile viruses RNA. The neonate was discharged after 6 days of hospitalization and was healthy at 10 days of life. The mother had no underlying conditions and reported fever, headache, and myalgia 5 days before delivery. Laboratory tests for OROV were not performed. Intra-household contacts had OROV RNA detected by RT-PCR in serum samples in the same period (Table 2).

Therefore, among the 2 infections reported in the first trimester of pregnancy, 1 resulted in spontaneous abortion and the other in a live-born infant with dysgenesis of the corpus callosum but no other apparent anomalies. Of the 13 infections reported in the third trimester, 1 possible intrapartum transmission occurred (i.e., a neonate had clinical manifestations) and 11 were asymptomatic cases. We found no anomalies in pregnancies affected by third-trimester infections (Table 2).

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Discussion

This case series highlights the potential implications of OROV infection during pregnancy, including evidence of peripartum transmission supported by a neonate with a positive test manifesting Oropouche fever–related signs and symptoms. In addition, a case of spontaneous abortion and a case of fetal dysgenesis of the corpus callosum were reported. The detection of OROV RNA in the placenta was not related to its detection in the serum samples of neonates, and those cases did not have congenital abnormalities.

Only recently, with the spread of the disease to extra-Amazon regions of Brazil and the increasing transmission in the human population, have severe cases of Oropouche fever started to be reported, including deaths, spontaneous abortions, stillbirths, and congenital conditions such as microcephaly (20,21). The emergence of a novel OROV reassortant lineage might be linked with those cases, as suggested by previous studies (4,22–24).

This case series from Espírito Santo suggests a potential link between first-trimester OROV infections and adverse outcomes, including 1 spontaneous abortion and a live-born infant with a brain abnormality, despite spontaneous aborting being a common occurrence in pregnancy. In contrast, 13 third-trimester infections resulted in healthy term deliveries. However, further research is needed to confirm this association, given that adverse pregnancy outcomes have also been reported in late pregnancy infections (4). Although third-trimester infections resulted in live births, 5 cases showed evidence of placenta infection, and 1 involved possible intrapartum transmission after spontaneous rupture of the membranes followed by cesarean, resulting in neonatal disease. Cases of intrapartum transmission are also reported in cases of dengue, chikungunya, and yellow fever infections (5). In this case, the period between the postpartum discharge and the neonate hospital admission with Oropouche fever clinical manifestations was 1 day, reinforcing the improbability of infection by vector biting and the possibility of intrapartum transmission.

Considering the number of pregnant women with confirmed OROV infection at different stages of pregnancy under follow-up in Espírito Santo, the findings among those who delivered highlight the possibility of increasing unfavorable outcomes. Therefore, ongoing evaluation of the effects of infection at different stages of pregnancy and its outcomes is necessary (25). Of note, no instances of preterm birth, low weight and length, or an Apgar score <7 were reported. The association between preterm birth and OROV infection remains unclear (21).

The first indication of possible OROV vertical transmission in Brazil was reported by the Ministry of Health in July 2024 on the basis of identification of OROV-specific antibodies in serum and cerebrospinal fluid samples from 4 neonates with microcephaly and in 1 case of fetal death in which OROV was detected in the umbilical cord, placenta, and various organs (26). Spontaneous abortions, stillbirths, and congenital conditions linked to OROV infection have been reported in Pernambuco, Manaus, Acre, Ceará, Bahia, and Pará States (4,21,27,28). Similar outcomes after vertical transmission have been observed in other Orthobunyavirus-infected pregnant animals and humans (29).

Despite the impossibility of establishing causality about the infection’s teratogenic effects in those studies, experimental findings in neonatal mice submitted to subcutaneous inoculation with OROV showed infection affecting the central nervous system, especially the posterior parts of the brain, reaching the spinal cord and spreading to the brain parenchyma (30). In addition, mice neurons were the target cells affected by OROV, having glial reaction, astrocyte activation, and neuronal apoptosis (31). The corpus callosum dysgenesis reported in Espírito Santo and Acre States support these findings (27). In adults, neurologic disease and the presence of OROV in cerebrospinal fluids were previously reported (32,33), and in vitro experiments demonstrated an inflammatory response and tissue damage when human neural cells were infected with OROV (34). In addition, an analogy of Zika virus infection leading to congenital Zika syndrome is plausible, because both Zika virus and OROV manifest in neurotropism and can cross the placental barrier (35). Those findings contribute to support the biological plausibility of teratogenic effects resulting from OROV infections. Nevertheless, prospective studies are needed to confirm causality by assessing temporality, association strength, and consistency (36,37). Such studies should also approach complex models of multicausality that consider social and other determinants. The mechanisms of placental transmission, maternal immunity, and fetal susceptibility also require further investigation (27).

Espírito Santo, as the state with the highest incidence of Oropouche fever cases outside the original endemic region in Brazil, underscores the effect of epidemics in areas with high vectorial presence and an immune-naive population, including a considerable incidence among women of reproductive age (18). This scenario raises concerns about pregnant women visiting those areas, particularly after the US Centers for Disease Control and Prevention issued recent advice to avoid nonessential travel to Espírito Santo because of the current local epidemiologic situation, marked by high incidence and reports of suspected and confirmed deaths (38,39). Transmission in the state primarily occurs in small cities, where ecologic conditions, such as plantations providing organic matter and humidity, are ideal for breeding C. paraensis mosquitoes, given that those conditions support the laying of eggs by the female (22). Therefore, this experience serves as a warning for other areas in Brazil to which Oropouche fever is not endemic. Health professionals in such areas must be vigilant, ensuring that illnesses during pregnancy are further investigated to avoid complications. Of note, this case series includes reports of pregnant women with OROV infections in the absence of fever, which must be considered by clinicians and for surveillance purposes. The Oropouche fever outbreak emphasizes the need for surveillance systems to adapt quickly to emerging and reemerging infectious disease threats.

Our study also highlights the need for effective protocols for preventing and managing OROV infection in pregnant women. The previous experience with congenital Zika syndrome could contribute to defining these actions. Suggested measures included considering Oropouche fever as a differential diagnosis for febrile illness, providing laboratory tests for symptomatic pregnant women aiming for early diagnosis, conducting serial ultrasounds to monitor fetal malformations and growth restriction, performing developmental and neurologic evaluations of neonates, and counseling pregnant women on vector biting protection, sexual protection, and avoiding travel to endemic areas (28,38,40–42). RT-PCR should be performed within 5 days of symptom onset, and pregnant women should be encouraged to seek medical care promptly. The test used in Espírito Santo has an amplification efficiency >98% and a limit of detection ranging from 2 to 20 copies/reaction, but it has not yet been compared with other diagnostic tests, and the possibility of false-positives or false-negatives must be considered (17). The incubation period for OROV infection ranges from 3 to 10 days (41).

Moreover, the response in endemic regions should focus on establishing robust monitoring systems to detect and report cases early, genomic surveillance, educating communities on preventing vector exposure, and ensuring health services and healthcare professionals are equipped to recognize and manage Oropouche fever cases, including congenital and neonatal disease cases. Future studies should investigate the viral, vector, human, and environmental determinants of OROV spread and outcomes, including its urbanization, by using the One Health approach (41). This comprehensive perspective will help prevent and manage cases during pregnancy and in neonates.

In conclusion, Oropouche fever in pregnancy might result in vertical (including intrapartum) transmission, potentially leading to spontaneous abortion and fetus malformation. Further investigations are necessary to establish causality between infection during pregnancy and these outcomes. Meanwhile, health systems, healthcare professionals, and communities must be prepared to prevent, detect, monitor, and respond to OROV infection during pregnancy and provide appropriate follow-up and treatment to the mothers and neonates affected.

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Dr. Cola is a nurse at the Special Center for Epidemiological Surveillance of the State Health Department of Espírito Santo. His primary research interests include the epidemiology of arboviruses. Dr. Brioschi dos Santos is a nurse at the Center for Strategic Information and Response in Health Surveillance of the State Health Department of Espírito Santo. Her primary research interests include health emergency response and maternal health.

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Maternal and Fetal Implications of Oropouche Fever, Espírito Santo State, Brazil, 2024

https://wwwnc.cdc.gov/eid/article/31/4/24-1986_article

Oropouche Fever, Espírito Santo, Brazil, 2024

**Shiloh** · June 1, 2025, 01:35 PM

Source: https://www-regiaonews-com-br.transl..._x_tr_pto=wapp

Oropouche fever spreads in Brazil: more than 10,000 cases and four deaths confirmed
This represents an increase of 56.4% compared to the same period in 2024, when 6,440 cases were recorded.
May 27, 2025 - 07:38

Brazil has recorded at least four deaths caused by oropouche fever in 2025. To date, three deaths have been confirmed by the Rio de Janeiro State Health Department (SES-RJ) and one by the Espírito Santo Health Department (Sesa-ES). The first deaths from the disease in the world were recorded in the country in July last year.

Regarding infections, as of May 16, the Ministry of Health documented 10,072 cases of oropouche in Brazil, according to the weekly bulletin of the Emergency Operations Center (COE). This represents an increase of 56.4% compared to the same period in 2024, when 6,440 cases were recorded.

Throughout last year, 13,853 infections were confirmed. In 2023, the country had 833 occurrences.

The most affected state this year is Espírito Santo, with 6,118 cases. Rio de Janeiro also stands out, with 1,900 cases; Paraíba, with 640; and Ceará, with 573.

According to the COE, people between 20 and 59 years old represent 70.5% of those infected. Among children under 1 year old, 12 cases were registered, six in Rio de Janeiro, four in Espírito Santo, one in Ceará and one in Paraíba.

What explains the rise in cases?

Last year, the ministry pointed out that the increase was associated with the expansion of tests to detect the disease, distributed throughout the national network of Central Public Health Laboratories (Lacen). As a result, cases, which until then had been concentrated in the North Region, began to be identified in other areas.

There is also a combination of factors that must be considered, according to infectologist Jessica Fernandes Ramos, member of the Infectious Diseases Unit at Hospital Sírio-Libanês.

An important aspect, says Jessica, is the mutation of the virus responsible for the disease. Last year, a new strain of OROV was detected by the Oswaldo Cruz Foundation (Fiocruz). According to the organization, it probably emerged in Amazonas between 2010 and 2014, and spread silently in the second half of the 2010s.

Pedro Vasconcelos, emeritus researcher at the Evandro Chagas Institute (IEC), explained in an interview with Estadão that climate change, deforestation and human migrations are other factors that contribute to the spread of the virus.

First deaths

According to Jessica, the concern is now greater than in previous years due to the number of deaths recorded. "Before, it was an arbovirus with a more benign course, with no deaths recorded," she notes....

Announcement

Brazil: 2024/2025 Oropouche virus

Brazil: 2024/2025 Oropouche virus

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