Serological and viral prevalence of Oropouche virus (OROV): A systematic review and meta-analysis from 2000-2024 including human, animal, and vector surveillance studies

Serological and viral prevalence of Oropouche virus (OROV): A systematic review and meta-analysis from 2000-2024 including human, animal, and vector surveillance studies | medRxiv /* */ /* */ <!-- <!-- /*! * yepnope1.5.4 * (c) WTFPL, GPLv2 */ (function(a,b,c){function d(a){return"[object Function]"==o.call(a)}function e(a){return"string"==typeof a}function f(){}function g(a){return!a||"loaded"==a||"complete"==a||"uninitialized"==a}function h(){var a=p.shift();q=1,a?a.t?m(function(){("c"==a.t?B.injectCss:B.injectJs)(a.s,0,a.a,a.x,a.e,1)},0):(a(),h()):q=0}function i(a,c,d,e,f,i,j){function k(b){if(!o&&g(l.readyState)&&(u.r=o=1,!q&&h(),l.onload=l.onreadystatechange=null,b)){"img"!=a&&m(function(){t.removeChild(l)},50);for(var d in y[c])y[c].hasOwnProperty(d)&&y[c][d].onload()}}var j=j||B.errorTimeout,l=b.createElement(a),o=0,r=0,u={t:d,s:c,e:f,a:i,x:j};1===y[c]&&(r=1,y[c]=[]),"object"==a?l.data=c:(l.src=c,l.type=a),l.width=l.height="0",l.onerror=l.onload=l.onreadystatechange=function(){k.call(this,r)},p.splice(e,0,u),"img"!=a&&(r||2===y[c]?(t.insertBefore(l,s?null:n),m(k,j)):y[c].push(l))}function j(a,b,c,d,f){return q=0,b=b||"j",e(a)?i("c"==b?v:u,a,b,this.i++,c,d,f):(p.splice(this.i++,0,a),1==p.length&&h()),this}function k(){var a=B;return a.loader={load:j,i:0},a}var l=b.documentElement,m=a.setTimeout,n=b.getElementsByTagName("script")[0],o={}.toString,p=[],q=0,r="MozAppearance"in l.style,s=r&&!!b.createRange().compareNode,t=s?l:n.parentNode,l=a.opera&&"[object Opera]"==o.call(a.opera),l=!!b.attachEvent&&!l,u=r?"object":l?"script":"img",v=l?"script":u,w=Array.isArray||function(a){return"[object Array]"==o.call(a)},x=[],y={},z={timeout:function(a,b){return b.length&&(a.timeout=b[0]),a}},A,B;B=function(a){function b(a){var a=a.split("!"),b=x.length,c=a.pop(),d=a.length,c={url:c,origUrl:c,prefixes:a},e,f,g;for(f=0;f<d;f++)g=a[f].split("="),(e=z[g.shift()])&&(c=e(c,g));for(f=0;f<b;f++)c=x[f](c);return c}function g(a,e,f,g,h){var i=b(a),j=i.autoCallback;i.url.split(".").pop().split("?").shift(),i.bypass||(e&&(e=d(e)?e:e[a]||e[g]||e[a.split("/").pop().split("?")[0]]),i.instead?i.instead(a,e,f,g,h):(y[i.url]?i.noexec=!0:y[i.url]=1,f.load(i.url,i.forceCSS||!i.forceJS&&"css"==i.url.split(".").pop().split("?").shift()?"c":c,i.noexec,i.attrs,i.timeout),(d(e)||d(j))&&f.load(function(){k(),e&&e(i.origUrl,h,g),j&&j(i.origUrl,h,g),y[i.url]=2})))}function h(a,b){function c(a,c){if(a){if(e(a))c||(j=function(){var a=[].slice.call(arguments);k.apply(this,a),l()}),g(a,j,b,0,h);else if(Object(a)===a)for(n in m=function(){var b=0,c;for(c in a)a.hasOwnProperty(c)&&b++;return b}(),a)a.hasOwnProperty(n)&&(!c&&!--m&&(d(j)?j=function(){var a=[].slice.call(arguments);k.apply(this,a),l()}:j[n]=function(a){return function(){var b=[].slice.call(arguments);a&&a.apply(this,b),l()}}(k[n])),g(a[n],j,b,n,h))}else!c&&l()}var h=!!a.test,i=a.load||a.both,j=a.callback||f,k=j,l=a.complete||f,m,n;c(h?a.yep:a.nope,!!i),i&&c(i)}var i,j,l=this.yepnope.loader;if(e(a))g(a,0,l,0);else if(w(a))for(i=0;i (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0];var j=d.createElement(s);var dl=l!='dataLayer'?'&l='+l:'';j.src='//www.googletagmanager.com/gtm.js?id='+i+dl;j.type='text/javascript';j.async=true;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-P4HH5NV'); Skip to main content Home About Submit ALERTS / RSS Search for this keyword Advanced Search Serological and viral prevalence of Oropouche virus (OROV): A systematic review and meta-analysis from 2000-2024 including human, animal, and vector surveillance studies Emilie Toews , Sabah Shaikh , Shaila Akter , View ORCID Profile Caseng Zhang , Anabel Selemon , View ORCID Profile Rahul K Arora , Niklas Bobrovitz , Thomas Jaenisch , View ORCID Profile Mairead G Whelan , Harriet Ware doi: https://doi.org/10.1101/2025.07.10.25331249 Emilie Toews 1 Centre for Health Informatics, Cumming School of Medicine, University of Calgary , Calgary, Canada Find this author on Google Scholar Find this author on PubMed Search for this author on this site Sabah Shaikh 1 Centre for Health Informatics, Cumming School of Medicine, University of Calgary , Calgary, Canada Find this author on Google Scholar Find this author on PubMed Search for this author on this site Shaila Akter 2 Heidelberg Institute of Global Health, Heidelberg University Hospital , Im Neuenheimer Feld 130/3, 69120, Heidelberg, Germany 3 Radboud University Medical Center, Radboud Institute of Health Sciences (RIHS), Department of Dentistry—Quality and Safety of Oral Healthcare , Nijmegen, Netherlands Find this author on Google Scholar Find this author on PubMed Search for this author on this site Caseng Zhang 4 Faculty of Medicine, University of Ottawa , Ottawa, Canada Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Caseng Zhang Anabel Selemon 1 Centre for Health Informatics, Cumming School of Medicine, University of Calgary , Calgary, Canada Find this author on Google Scholar Find this author on PubMed Search for this author on this site Rahul K Arora 1 Centre for Health Informatics, Cumming School of Medicine, University of Calgary , Calgary, Canada Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Rahul K Arora Niklas Bobrovitz 1 Centre for Health Informatics, Cumming School of Medicine, University of Calgary , Calgary, Canada 5 Department of Emergency Medicine, University of Calgary , Calgary, Canada Find this author on Google Scholar Find this author on PubMed Search for this author on this site Thomas Jaenisch 2 Heidelberg Institute of Global Health, Heidelberg University Hospital , Im Neuenheimer Feld 130/3, 69120, Heidelberg, Germany 6 Center for Global Health & Department of Epidemiology, Colorado School of Public Health , Aurora, Colorado, U.S.A Find this author on Google Scholar Find this author on PubMed Search for this author on this site Mairead G Whelan 1 Centre for Health Informatics, Cumming School of Medicine, University of Calgary , Calgary, Canada Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Mairead G Whelan For correspondence: mairead.whelan{at}ucalgary.ca Harriet Ware 1 Centre for Health Informatics, Cumming School of Medicine, University of Calgary , Calgary, Canada Find this author on Google Scholar Find this author on PubMed Search for this author on this site Abstract Full Text Info/History Metrics Supplementary material Data/Code Preview PDF Abstract Background Oropouche virus (OROV) is an emerging arbovirus primarily transmitted by biting midges and is increasingly recognized as a public health threat in Central and South America. With over 11,000 confirmed cases reported in 2024, a ten-fold increase from the previous year, its transmission dynamics and true burden remain poorly understood due to diagnostic challenges and fragmented surveillance systems. Objective This systematic review and meta-analysis (SRMA) synthesizes OROV prevalence data in humans and summarizes the available data for vectors and non-human hosts sampled between 2000 and 2024 to provide updated estimates and identify key surveillance gaps. Methods We systematically searched Web of Science, PubMed, Embase, Medline, and LILACS for OROV seroprevalence and viral prevalence studies in human, insect, and animal populations, published up to September 12, 2024. The review protocol was registered with PROSPERO (CRD42024551000). Studies were extracted in duplicate, and data were meta-analyzed using generalized linear mixed-effects models. Risk of bias was appraised using a modified Joanna Briggs Institute checklist. Results We included 71 articles reporting serological or viral prevalence of OROV across nine countries. Between 2000–2024, pooled human seroprevalence among individuals with febrile illness or suspected of Oropouche infection was 12.6% [95% CI 5.3-26.9%] across four South American countries and seroprevalence of 1.1% [95% CI 0.5-2.3%] was observed in asymptomatic groups. Viral prevalence among individuals with febrile illness or suspected of Oropouche infection was 1.5% [0.8-3.0%] across seven South American countries and Haiti. Most studies used convenience sampling and RT-PCR or hemagglutination assays. In vector populations, positive OROV prevalence in Aedes aegypti and Culex quinquefasciatus was reported in two of 18 sources, while 10.0% and 7.5% animal host prevalence was reported in dogs and cattle, respectively. We found high risk of bias in 11.3% of studies in our critical appraisal, with most animal, human, and vector studies falling in the moderate risk of bias range. Conclusions Despite rising numbers of OROV reported cases, prevalence estimates remain limited by sparse surveillance and variable methodology. This review highlights the urgent need for standardized serological assays, community-based studies, and expanded surveillance in animal and vector reservoirs. A One Health approach is essential to monitor OROV transmission and inform regional preparedness efforts. Author summary Oropouche virus is a pathogen carried by biting midges and some other insect vectors that causes fever and flu-like illness in people, and it can also be carried by animals. Cases of Oropouche virus have been rising in Central and South America, with approximately 11,000 confirmed cases in 2024 – a ten-times increase from the previous year. Despite the growing outbreaks, we still know little about how many people and animals have been infected; studies testing at-risk populations for viral infection or the presence of antibodies are valuable tools in filling these knowledge gaps. To address this, we reviewed such studies published from 2000 to 2024 that tested people, animals, and insects for Oropouche virus, and produced estimates of the virus’ prevalence in these populations to better understand its spread and detection. We found that in humans with suspected infection in four South American countries, i.e. with fever and related symptoms, 12.6% of them had antibodies for Oropouche – indicating a history of infection. The prevalence of active viral infections in similar populations was 1.5%. In asymptomatic people, the prevalence of antibodies was lower, at 1.1%. We also found small presence of the virus in insect vectors and animals, namely dogs and cattle. Overall, the studies had varying methods especially with regards to diagnostic tests, and the number of studies is still very limited, especially in animals and insects. Our findings highlight the urgent need for better tools, standardized research methods, and an increase in community surveillance studies across species to better understand Oropouche, prevent future outbreaks, and best respond to the health needs of affected communities. Introduction The Oropouche virus (OROV), a vector-borne arbovirus from the Peribunyaviridae family typically transmitted by biting midges, is rapidly gaining prominence as a critical public health threat in Central and South America. As of November 2024, the World Health Organization (WHO) reported over 11,000 confirmed cases, marking a tenfold increase from 2023 ( 1 ). OROV infection causes Oropouche fever, an acute illness characterized by fever, headache, joint pain, and, in severe cases, neurological complications. Recent evidence from the ongoing outbreak in Central and South America suggests that OROV may additionally be transmitted sexually and vertically during pregnancy, potentially causing severe congenital anomalies, including microcephaly ( 2 ). In addition, early data raise the concern that OROV’s vector range may be expanding both geographically and into other carrying vectors beyond the biting midge, for example Culex mosquitoes. Accurate prevalence estimates are critical for tracking OROV’s spread and informing targeted public health interventions. Arboviruses like OROV are frequently under-reported or misdiagnosed due to clinical similarities with other acute febrile illnesses, cross-reactivity in diagnostic tests, and the high proportion of mild or asymptomatic cases that evade detection ( 3 ). Additionally, evidence of infection in animal reservoirs like birds and mammals remains poorly defined, complicating efforts to assess zoonotic spillover risks. Serological studies provide key insights into population-level exposure and geographic spread among both human and non-human hosts, while viral prevalence studies help distinguish between active outbreaks and endemic circulation. Despite the value of these surveillance estimates, data remain largely fragmented across published literature, underscoring the need for systematic reviews and meta-analyses to identify trends. Recent evidence indicates wide variation in both human seroprevalence and viral prevalence. One study in Colombia estimated 2% seroprevalence in healthy individuals ( 4 ), while another estimated 40% seroprevalence in febrile patients in a high-transmission zone in Brazil ( 5 ). Another recent paper estimated 6.3% average seroprevalence in Latin America, including samples pooled from a range of population types ( 6 ). A viral prevalence study in Colombia showed RT-qPCR identified estimates less than 10% in surveyed febrile populations ( 7 ). Previous reviews by Romero-Alvarez ( 8 ) and Walsh ( 9 ) have documented case counts and virus detection locations, but lack synthesized prevalence estimates and updated data in the context of recent 2024 outbreaks. Other recent literature reviews have either focused exclusively on human seroprevalence ( 10 ) or employed narrative synthesis without meta-analysis ( 11 ), limiting understanding of OROV circulation, while our review provides a comprehensive synthesis of prevalence data across human, vector, and animal hosts. In this paper, our objective was to systematically review and meta-analyze OROV prevalence data in humans with an emphasis on evidence from the last decade (2000–2024) to provide an updated and comprehensive synthesis. Additionally, we review the literature on OROV prevalence in non-human reservoirs, offering a preliminary overview of its circulation in non-human hosts. To enhance accessibility and utility for researchers and public health professionals, the compiled data and methodology from this review are made available through the interactive and open-access ArboTracker dashboard and data platform ( 12 ). By adopting a One Health approach, this study aims to strengthen public health preparedness and guide surveillance strategies to mitigate OROV’s impact in the Americas. Methods The protocol for this SRMA is registered with PROSPERO as part of a review of arbovirus prevalence studies ( CRD42024551000 ) and is openly accessible on the ArboTracker dashboard website ( https://new.serotracker.com/pathogen/arbovirus/dashboard ). We searched five databases (Web of Science, PubMed, Embase, Medline, and LILACS) on September 12, 2024, using comprehensive search terms related to OROV and prevalence estimates, developed with input from a health science librarian (Supplementary File B). Additional articles were found by screening reference lists from reviews published between 2021 and 2024. References were uploaded into Covidence ( 13 ) for de-duplication and screening. Titles and abstracts were independently reviewed by pairs of reviewers, followed by full-text screening of eligible articles. A third reviewer resolved discrepancies. Non-English articles were translated via Google Translate or Microsoft Word’s translate function. Cross-sectional, case-control and cohort studies were included if they reported OROV prevalence estimates for humans, non-human animals, or insect populations with a specific end date in a defined geographic location. We included peer-reviewed literature, preprints, grey literature, and media reports without language restrictions. Full inclusion and exclusion criteria can be found in Supplementary File D. Included articles were uploaded into an AirTable database for data extraction. For each source, we collected bibliographic details and prevalence estimates, along with information on study design, testing methods, and population characteristics. Where an article or source contains multiple prevalence estimates stratified by time, geography, non-overlapping populations, test type, or gender, we split the article into multiple “studies”—for the purpose of this review, “study” means a distinct estimate. Overlapping stratifications were avoided except for when test type, and gender subgroup estimates were available in different populations, timeframes, or geographic locations. Data extraction was performed by one reviewer and independently verified by a second, with any disputes being resolved through discussion. Data from included articles can also be found on the ArboTracker dashboard, alongside seroprevalence studies for six other arboviruses as part of a larger living review ( 12 ). We critically appraised all studies using a modified version of the Joanna Briggs Institute (JBI) checklist for prevalence studies ( Supplement ary File E) that has previously been used in seroprevalence reviews ( 14 ). To assess risk of bias, 6/8 items on the checklist were determined by an automated decision rule, with the final two items verified by dual manual review. Each study was assigned a rating of low, moderate, or high risk of bias by the decision rule based on the specific combination of JBI checklist ratings for that study. This method has been validated against overall risk of bias assessments derived manually by two independent reviewers for previously collected seroprevalence studies, showing good agreement with manual review (intraclass correlation 0.77, 95% CI 0.74 to 0.80; n = 2,070 studies) ( 14 ). Study and population characteristics were summarized using descriptive statistics (i.e. counts and percentages). To capture timely evidence from the last decade and provide a current-day snapshot of the virus’s circulation, we included only studies that concluded sampling between 2000 and 2024 in the meta-analysis. We meta-analyzed the seroprevalence and viral prevalence of OROV in humans using generalized linear mixed-effects models and reported point estimates and 95% confidence intervals. Subgroup analyses were conducted, stratified by expected sources of study heterogeneity, including country and population type (febrile patients or suspected cases vs. general population). Heterogeneity was assessed using the I 2 statistic to quantify the proportion of variation attributable to true differences rather than chance. Analyses were performed in R [meta and metafor packages, R version 4.4.3]. Results Search results The database searches identified 3,220 abstracts, and an additional 38 unique abstracts were identified from the reference lists of recent reviews ( 3 , 9 – 11 , 15 ) ( Figure 1 ). Following the abstract and title screening phase, we screened 131 full-text articles, ultimately including 71 articles in the review. Human and vector studies were included in 59 and 18 of the 71 publications, respectively. The 71 articles contained a total of 287 unique viral or serological prevalence studies (detailed references and information available in Supplementary Table A and B). Sixty-one articles sampled in 2000 or later were included in the meta-analysis ( Figure 1 ). Download figure Open in new tab Figure 1: PRISMA flowchart for inclusion and exclusion of Oropouche virus literature. Characteristics of included studies Nine Caribbean and South and Central American countries were represented among the studies included in the descriptive analysis, including Bolivia, Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Haiti, Paraguay, and Peru. Most studies sampled human populations (60%), with fewer sampling insect (20%) and non-human animal (19%) populations. About half of human studies estimated seroprevalence (57%) while 43% estimated viral prevalence ( Table 1 ). Convenience sampling was the most frequent sampling method. Sampling frames in human studies were primarily febrile patients (63%) and asymptomatic communities (27%). In studies sampling in 2000-2024, febrile patients constituted a greater proportion of sampling frames (75%), with a smaller proportion of studies sampling asymptomatic communities (12%). Among the testing strategies used to measure prevalence in humans, most studies used reverse transcription polymerase chain reaction (RT-PCR) (61%) or enzyme-linked immunosorbent (ELISA) (14%) assays. Only studies that concluded sampling in 2000-2024 were included in the subsequent results (n=195), which included OROV estimates from 99 human studies and 96 vector studies. View this table: View inline View popup Table 1: Human study characteristics (author, year, location, population, sample size etc) Human seroprevalence Ninety-two studies reported estimates of human seroprevalence, with 38 studies sampling between 2000 and 2024. Pooled seroprevalence in humans with febrile illness or suspected Oropouche infection between 2000 and 2024 was 12.6% [95% CI 5.3 to 26.9%] (n=25) with substantial heterogeneity (I 2 99%) ( Figure 2 ). The studies were performed in Brazil (n=12), Colombia (n=6), Ecuador (n=2), and Peru (n=5). Pooled seroprevalence was 24.4% [95% CI 9.5 to 49.7%] in Brazil, 14.5% [95% CI 7.2 to 27.2%] in Colombia, and 7.0% [95% CI 0.3 to 61.9%] in Peru. A pooled estimate was not calculated for Ecuador as only two studies were included, which reported two estimates of 0.3% seroprevalence (Manock et al, 2004). Download figure Open in new tab Figure 2: Reported pooled seroprevalence from studies sampling participants with febrile illness or suspected of Oropouche infection in 2000 to 2024. Pooled seroprevalence among asymptomatic general populations between 2000 and 2024 was 1.1% [95% CI 0.5 to 2.3%] (n=13) with lower heterogeneity (I 2 92%) ( Figure 3 ). These studies were performed in Brazil (n=9) and Colombia (n=4). Pooled seroprevalence was similar in the two countries—1.0% [95% CI 0.4 to 2.7%] in Brazil and 1.8% [95% CI 0.7 to 4.7%] in Colombia. Download figure Open in new tab Figure 3: Reported pooled seroprevalence from studies sampling participants among asymptomatic general populations in 2000 to 2024. Human viral prevalence Seventy studies reported estimates of human viral prevalence with 61 studies sampling between 2000 and 2024. Pooled viral prevalence among individuals with febrile illness or suspected of Oropouche infection between 2000 and 2024 was 1.5% [95% CI 0.8 to 3.0%] with substantial heterogeneity (I2=99%) ( Figure 5 ). The 61 studies were performed in eight countries, with a range of viral prevalence of 0.2% [95% CI 0.0 to 2.8%] in Bolivia, 1.0% [95% CI 0.3 to 3.1%] in Brazil, 1.1% [95% CI 0.3 to 3.8%] in Ecuador, 3.1% [95% CI 1.3 to 7.0%] in Peru, and 3.5% [95% CI 0.8 to 14.2%] in Colombia, where at least three studies were included per country. Download figure Open in new tab Figure 5: Reported pooled viral prevalence from studies sampling participants in 2000 to 2024, n=61. Characteristics of vector studies and vector prevalence One hundred and twenty-five vector studies reported OROV prevalence, with 96 studies sampling in 2000 or later. Since 2000, OROV prevalence in vector populations has been estimated mostly through RT-PCR (70.8%) rather than through serological methods (29.2%). These studies were derived from insect vector populations (50.0%) and animal vector populations (50.0%) equally. Insect studies were most frequently available for mosquito species (93.8%), although there were 3 studies (6.3%) for OROV prevalence in biting midges ( Culicoides paraensis ) ( Table 2 - end of document ). Only four studies reported positive viral prevalence estimates, including in Aedes aegypti (1.2% prevalence) ( 16 ), Culex quinquefasciatus (0.6%; 2.1%) ( 16 , 17 ), and a non-specified mosquito population (0.4%) ( 18 ). View this table: View inline View popup Table 2: Summary of vector study characteristics For animal vector populations, OROV infection has most frequently been explored in primate species (37.5%), but also in birds (12.5%), opossum (8.3%), horses (8.3%), cows (6.3%), dogs (6.3%), cats (4.2%), coatis (4.2%), sloths (4.2%), and caimans, fish, sheep, and rodents (2.1% each) ( Table 2 ). Evidence of OROV infection was found in seven animal studies sampling after 2000. In three sources sampling four populations of non-human primates with evidence of OROV infection, seroprevalence ranged from 1%-7.7% ( 19 – 21 ). Lastly, two more sources revealed a non-zero OROV seroprevalence in species other than primates, with 10.0% and 7.5% respectively of sampled dogs and cattle ( 22 ), and 0.40% of sampled sheep ( 23 ) showing past OROV infection (Supplementary Table B - bibliographic summary of vector studies). Risk of Bias Most insect (34/48), and non-human animal (42/50) studies that sampled participants in 2000-2024 were rated moderate risk of bias, while most human (47%; 47/99) studies were rated low risk of bias and only 20% (20/99) of human studies and 8% (8/98) of vector studies had a high risk of bias. Risk of bias was typically higher in vector studies compared with human studies. A summary of the overall risk of bias ratings and a breakdown of each risk of bias indicator for all studies is available in Supplementary Table C. Discussion Summary of Key Findings in Humans and Context of the Current Outbreak This SRMA provides updated prevalence estimates of OROV in humans and vectors in the context of the recent 2024 outbreaks of the virus. Our seroprevalence estimate of OROV in the general population (1.1%) between 2000 and 2024 aligns closely with the 1.42% reported by Riccò et al. (2024). Our estimated seroprevalence in febrile individuals (12.6%) was also comparable to the 12.21% reported by Riccò et al. (2024). Estimated viral prevalence in febrile individuals (1.5%) across eight countries in South and Central America was somewhat lower than prior findings (3.86% in Riccò et al. 2024). The difference in viral prevalence may be explained by the difference in sampling periods and the inclusion of high prevalence estimates from the 1970s Brazilian epidemics of OROV in Riccò et al. Given the extensive clinical overlap between arboviral diseases, accurate diagnostic testing and reporting remain critical for effective surveillance and response. Our findings build upon previous reviews but offer several distinct contributions. While scoping reviews ( 11 , 15 , 24 ) have examined OROV circulation, none have compared prevalence data across humans, vectors, and animal hosts. Ricco et al. (2024)’s SRMA was not comprehensive, identifying 47 sources compared to 71 in our review, and did not differentiate between sampling time periods, further highlighting the need for updated evidence. Seroprevalence among the general population was low (1.1%), and the number of studies attempting to estimate OROV burden in asymptomatic or subclinical populations was limited. There was no indication of an increase over time, which could be due to the low number of studies. The higher proportion of studies performed in febrile populations, compared with the general population, underscores the emerging nature of the pathogen, implying that current OROV research and diagnostic efforts are reactionary, where most studies are conducted in response to rising arboviral or febrile disease incidence rather than as part of proactive surveillance efforts. This underscores the urgent need for systematic community-based studies to assess the full scope of OROV circulation, employing a sampling frame where potential geographical spread (and distance from sylvatic regions) are taken into account. Key Findings in Vector and Animal Reservoir Studies Despite the growing recognition of OROV as a public health threat, research on non-human reservoirs and vector dynamics remains scarce. About half of the studies included in this review examined OROV prevalence in insect or animal populations, with the majority detecting no evidence of current OROV infection. In the vector studies found, mosquito species including Culex quinquefasciatus and Aedes aegypti were found to harbour OROV ( 16 – 18 ), though it remains unclear whether they are capable of sustaining transmission cycles ( 25 ). The detection of OROV in a broad range of vectors is concerning, particularly given the question if C. quinquefasciatus and Culicoides sonorensis are able to spread the virus beyond its traditional range ( 26 ). Climate change-driven shifts in vector habitats could facilitate OROV transmission in new regions, mirroring the geographic expansion seen in other arboviruses such as West Nile virus ( 27 ). Similarly, the role of animal reservoirs remains poorly understood. Although OROV has been detected in non-human hosts such as primates, sheep, dogs, and cattle ( 19 – 23 ), the extent to which these species contribute to transmission remains uncertain. Dias et al (2024) detected OROV exposure in 7.5% and 10% of cattle and dogs respectively between 2016 and 2018 but could not find evidence of active infection in the same populations ( 28 ). No studies have sought to quantify OROV prevalence in animal vectors between 2018 and 2024, highlighting a major deficiency in the current body of OROV literature, especially given the current outbreak. Expanding surveillance efforts to include potential wildlife reservoirs is essential for understanding the full epidemiological cycle of OROV and mitigating spillover risks. There were few recent studies of animal and vector populations. Further studies are needed in this area to inform more robust estimates. Strengths and Limitations Our study offers a robust and up to date synthesis of OROV prevalence estimates across multiple host populations. Results are available open-access on an interactive ArboTracker dashboard and data platform ( 12 ). This review had limitations. First, significant heterogeneity exists across included studies, stemming from differences in geographic sampling, population demographics, diagnostic assays and outbreak periods. A recent analysis showed that differences in OROV ELISA seroprevalence results between population cohort types (e.g. febrile versus general population) had limited statistical significance when including additional controls for climate variables, which could indicate heterogeneity at least in sample frame is not a substantial limitation, but these results should still be interpreted with appropriate attention ( 6 ). For serological assays in particular, prevalence results are impacted by assay type and performance and whether or not investigators conducted a screening or confirmatory neutralizing test. Cross-reactivity is a known problem for arboviral assays and assay information is poorly reported in published literature, which further limits the interpretation of results ( 29 ). These assay considerations have not been accounted for or statistically adjusted in our analysis. However, use of a valid assay was included as an element in our critical appraisalFuture work on the standardization of testing protocols, assay evaluation, and surveillance strategies is needed to enhance comparability across studies. Second, there may be selection bias in the human studies, which primarily used convenience sampling. As a result, the results need to be interpreted with some caution. Ideally, studies would employ random sampling to obtain representative samples of the population. Third, our ability to analyze exposure in animal and vector populations was limited by the small number of studies and cross sectional design of viral testing studies. Further studies are needed in this area. Future Directions and Public Health Implications Despite recent advances in OROV research, critical knowledge gaps remain. Community-based seroprevalence studies are needed to assess true population exposure, particularly in non-outbreak periods. Since the completion of our literature search, OROV has been detected in Panama, with imported cases reported in Canada and the Cayman Islands ( 30 ). This geographic expansion further underscores the need for coordinated international surveillance. Future research should prioritize vector competence studies to clarify the transmission potential of Culex , Aedes , and other suspected vectors. Standardizing diagnostic assays, including the development of interoperable laboratory protocols, would facilitate cross-study comparisons and improve the reliability of prevalence estimates. Our findings support the need for comprehensive, standardized arbovirus research study protocols and surveillance programs incorporating OROV. A One Health approach that integrates human, animal, and environmental surveillance will be essential for mitigating future outbreaks, especially given the concerning lack of knowledge on animal and insect hosts in the OROV transmission pathway. In light of the increasing frequency and severity of OROV epidemics, proactive public health interventions, including enhanced vector control and improved diagnostic capacity, should be prioritized. Conclusion This systematic review and meta-analysis provides the most up-to-date synthesis of OROV prevalence estimates in humans, vectors, and potential animal hosts. These findings highlight the increasing public health threat posed by OROV, the gaps in current surveillance efforts, and the need for more systematic studies to inform mitigation strategies. Addressing these gaps through coordinated research and policy initiatives will be essential for controlling the spread of OROV and reducing its impact on affected populations. Conflict disclosure statement MGW and HW contributed equally as joint final authors. MGW, HW, HR, SK, SS, AS, ET, NB, and RKA report funding for this project from the University of Calgary (Transdisciplinary Connector Grant), Canadian Institutes of Health Research, and the Public Health Agency of Canada (through Canada’s COVID-19 Immunity Task Force, 2021-HQ-00056). MGW, HW, HR, SK, SS, AS, ET, NB, and RKA report additional separate funding, unrelated to the project, from the Canadian Medical Association Joule Innovation Fund, WHO, the Robert Koch Institute, and the Food and Agriculture Organization of the United Nations. RKA is employed at OpenAI and receives equity compensation as part of the standard compensation package; RKA was also previously a venture fellow at Flagship Pioneering, minority shareholder of Alethea Medical, and has received funding from the Rhodes Trust and Open Philanthropy. YR, SA, TJ, and MC report funding for this project from European Commission ReCoDID and Contagio grants (EC/825746 and EC/101137283). YR, TJ, and MC report additional funding, unrelated to this project, from the Bill & Melinda Gates Foundation Serosurveillance Grant (GATES/INV-039656) and the Center for Disease Control Air Quality Contract (CDC/75D30123C17606). TJ and SA report funding for this project from the German Research Foundation (grant number 451956976). Data availability statement Study data will be made available through the interactive and open-access ArboTracker dashboard and data platform. Acknowledgements We thank our talented research team and many alumni of the SeroTracker group, as well as the team working at the Universities of Heidelberg and Colorado. We also thank collaborators at the emeritus COVID-19 Immunity Task Force and colleagues affiliated with the Centre for Health Informatics for helpful discussions. This manuscript does not necessarily reflect the views of WHO or any other funder. Footnotes ↵ * Co-last authors References 1. ↵ Mohapatra RK , Mishra S , Satapathy P , Kandi V , Tuglo LS . Surging Oropouche virus (OROV) cases in the Americas: A public health challenge . New Microbes New Infect . 2024 Mar 26; 59 : 101243 . OpenUrl PubMed 2. ↵ Schwartz DA , Dashraath P , Baud D . Oropouche Virus (OROV) in Pregnancy: An Emerging Cause of Placental and Fetal Infection Associated with Stillbirth and Microcephaly following Vertical Transmission . Viruses . 2024 Sep; 16 ( 9 ): 1435 . OpenUrl CrossRef PubMed 3. ↵ Zhang Y , Liu X , Wu Z , Feng S , Lu K , Zhu W , et al. Oropouche virus: A neglected global arboviral threat . Virus Res . 2024 Mar 1; 341 : 199318 . OpenUrl CrossRef PubMed 4. ↵ Gil-Mora J , Acevedo-Gutiérrez LY , Betancourt-Ruiz PL , Martínez-Diaz HC , Fernández D , Bopp NE , et al. Arbovirus Antibody Seroprevalence in the Human Population from Cauca, Colombia . 2022 Dec 14 [cited 2024 Nov 3]; Available from: https://www.ajtmh.org/view/journals/tpmd/107/6/article-p1218.xml 5. ↵ Carvalho VL , Azevedo RSS , Carvalho VL , Azevedo RS , Henriques DF , Cruz ACR , et al. Arbovirus outbreak in a rural region of the Brazilian Amazon . J Clin Virol . 2022 Jun 1; 150 – 151 :105155. 6. ↵ Fischer C , Frühauf A , Inchauste L , Cassiano MHA , Ramirez HA , Barthélémy K , et al. The spatiotemporal ecology of Oropouche virus across Latin America: a multidisciplinary, laboratory-based, modelling study . Lancet Infect Dis [Internet]. [cited 2025 Jun 4]; Available from : doi: 10.1016/S1473-3099(25)00110-0 OpenUrl CrossRef 7. ↵ Ciuoderis KA , Berg MG , Perez LJ , Hadji A , Perez-Restrepo LS , Aristizabal LC , et al. Oropouche virus as an emerging cause of acute febrile illness in Colombia . Emerg Microbes Infect . 2022 Dec 31; 11 ( 1 ): 2645 – 57 . OpenUrl PubMed 8. ↵ Romero-Alvarez D , Escobar LE . Oropouche fever, an emergent disease from the Americas . Microbes Infect . 2018 Mar 1; 20 ( 3 ): 135 – 46 . OpenUrl CrossRef PubMed 9. ↵ Walsh CES , Robert MA , Christofferson RC . Observational Characterization of the Ecological and Environmental Features Associated with the Presence of Oropouche Virus and the Primary Vector Culicoides paraensis: Data Synthesis and Systematic Review . Trop Med Infect Dis . 2021 Sep; 6 ( 3 ): 143 . OpenUrl PubMed 10. ↵ Riccò M , Corrado S , Bottazzoli M , Marchesi F , Gili R , Bianchi FP , et al. (Re-)Emergence of Oropouche Virus (OROV) Infections: Systematic Review and Meta-Analysis of Observational Studies . Viruses . 2024 Sep; 16 ( 9 ): 1498 . OpenUrl PubMed 11. ↵ Wesselmann KM , Postigo-Hidalgo I , Pezzi L , Oliveira-Filho EF de , Fischer C , Lamballerie X de , et al. Emergence of Oropouche fever in Latin America: a narrative review . Lancet Infect Dis . 2024 Jul 1; 24 ( 7 ): e439 – 52 . OpenUrl PubMed 12. ↵ Whelan MG , Ware H , Ranka H , Kenny S , Shaikh S , Roell Y , et al. ArboTracker: a multipathogen dashboard and data platform for arbovirus seroprevalence studies . Lancet Infect Dis . 2024 Nov; 24 ( 11 ): e670 – 1 . OpenUrl PubMed 13. ↵ Veritas Health Innovation . Covidence . [cited 2025 Apr 24]. Covidence - Systematic review software. Available from: https://www.covidence.org/ 14. ↵ Bobrovitz N , Noël K , Li Z , Cao C , Deveaux G , Selemon A , et al. SeroTracker-RoB: A decision rule-based algorithm for reproducible risk of bias assessment of seroprevalence studies . Res Synth Methods . 2023 May; 14 ( 3 ): 414 – 26 . OpenUrl PubMed 15. ↵ Pereira TN , Virginio F , Souza JI , Moreira LA . Emergent Arboviruses: A Review About Mayaro virus and Oropouche orthobunyavirus . Front Trop Dis . 2021 Nov 7; 2 : 737436 . OpenUrl 16. ↵ da Silva Ferreira R , de Toni Aquino da Cruz LC , de Souza VJ , da Silva Neves NA , de Souza VC , Filho LCF , et al. Insect-specific viruses and arboviruses in adult male culicids from Midwestern Brazil . Infect Genet Evol . 2020 Nov 1; 85 : 104561 . OpenUrl PubMed 17. ↵ Cardoso BF , Serra OP , Heinen LB da S , Zuchi N , Souza VC de , Naveca FG , et al. Detection of Oropouche virus segment S in patients and in Culex quinquefasciatus in the state of Mato Grosso, Brazil . Mem Inst Oswaldo Cruz . 2015 Sep; 110 : 745 – 54 . OpenUrl CrossRef PubMed 18. ↵ Pereira-Silva JW , Ríos-Velásquez CM , Lima GR de , Santos EFM dos , Belchior HCM , Luz SLB , et al. Distribution and diversity of mosquitoes and Oropouche-like virus infection rates in an Amazonian rural settlement . PLOS ONE . 2021 Feb 16; 16 ( 2 ): e0246932 . OpenUrl CrossRef PubMed 19. ↵ Batista PM , Andreotti R , Chiang JO , Ferreira MS , Vasconcelos PFDC . Seroepidemiological monitoring in sentinel animals and vectors as part of arbovirus surveillance in the state of Mato Grosso do Sul, Brazil . Rev Soc Bras Med Trop . 2012 Apr; 45 ( 2 ): 168 – 73 . OpenUrl CrossRef PubMed 20. Laroque PO , Valença-Montenegro MM , Ferreira DRA , Chiang JO , Cordeiro MT , Vasconcelos PFC , et al. Levantamento soroepidemiológico para arbovírus em macaco-prego-galego (Cebus flavius) de vida livre no estado da Paraíba e em macaco-prego (Cebus libidinosus) de cativeiro do nordeste do Brasil . Pesqui Veterinária Bras . 2014 May; 34 : 462 – 8 . OpenUrl 21. ↵ Batista PM , Andreotti R , Almeida PS de , Marques AC , Rodrigues SG , Chiang JO , et al. Detection of arboviruses of public health interest in free-living New World primates ( Sapajus spp.; Alouatta caraya ) captured in Mato Grosso do Sul, Brazil . Rev Soc Bras Med Trop . 2013 Dec; 46 : 684 – 90 . OpenUrl CrossRef PubMed 22. ↵ Dias HG , Familiar-Macedo D , Garrido IO , dos Santos FB , Pauvolid-Corrêa A. Exposure of domestic animals to Mayaro and Oropouche viruses in urban and peri-urban areas of West-Central Brazil . One Health Outlook . 2024 Jul 1; 6 ( 1 ): 12 . OpenUrl PubMed 23. ↵ Pauvolid-Corrêa A , Campos Z , Soares R , Nogueira RMR , Komar N . Neutralizing antibodies for orthobunyaviruses in Pantanal, Brazil . PLoS Negl Trop Dis . 2017 Nov 1; 11 ( 11 ): e0006014 . OpenUrl CrossRef PubMed 24. ↵ Sciancalepore S , Schneider MC , Kim J , Galan DI , Riviere-Cinnamond A . Presence and Multi-Species Spatial Distribution of Oropouche Virus in Brazil within the One Health Framework . Trop Med Infect Dis . 2022 Jun 20; 7 ( 6 ). 25. ↵ Gallichotte EN , Ebel GD , Carlson CJ . Vector competence for Oropouche virus: a systematic review of pre-2024 experiments [Internet] . medRxiv ; 2024 [cited 2025 Apr 24]. p. 2024.10.17.24315699. Available from: https://www.medrxiv.org/content/10.1101/2024.10.17.24315699v1 26. ↵ McGregor BL , Connelly CR , Kenney JL. Infection, Dissemination, and Transmission Potential of North American Culex quinquefasciatus, Culex tarsalis, and Culicoides sonorensis for Oropouche Virus . Viruses . 2021 Feb; 13 ( 2 ): 226 . OpenUrl CrossRef PubMed 27. ↵ Samy AM , Elaagip AH , Kenawy MA , Ayres CFJ , Peterson AT , Soliman DE . Climate Change Influences on the Global Potential Distribution of the Mosquito Culex quinquefasciatus, Vector of West Nile Virus and Lymphatic Filariasis . PLOS ONE . 2016 Oct 3; 11 ( 10 ): e0163863 . OpenUrl CrossRef PubMed 28. ↵ Dias HG , Lima RC de , Barbosa LS , Souza TMA de , Badolato-Correa J , Maia LMS , et al. Retrospective molecular investigation of Mayaro and Oropouche viruses at the human-animal interface in West-central Brazil, 2016–2018 . PLOS ONE . 2022 Nov 17; 17 ( 11 ): e0277612 . OpenUrl PubMed 29. ↵ Kasbergen LMR , Nieuwenhuijse DF , de Bruin E , Sikkema RS , Koopmans MPG . The increasing complexity of arbovirus serology: An in-depth systematic review on cross-reactivity . PLoS Negl Trop Dis . 2023 Sep; 17 ( 9 ): e0011651 . OpenUrl CrossRef PubMed 30. ↵ World Health Organization . Oropouche virus disease [Internet] . Available from: https://www.who.int/news-room/fact-sheets/detail/oropouche-virus-disease . View the discussion thread. Back to top Previous Next Posted July 11, 2025. Download PDF Supplementary Material Data/Code Email Thank you for your interest in spreading the word about medRxiv. NOTE: Your email address is requested solely to identify you as the sender of this article. Your Email * Your Name * Send To * Enter multiple addresses on separate lines or separate them with commas. You are going to email the following Serological and viral prevalence of Oropouche virus (OROV): A systematic review and meta-analysis from 2000-2024 including human, animal, and vector surveillance studies Message Subject (Your Name) has forwarded a page to you from medRxiv Message Body (Your Name) thought you would like to see this page from the medRxiv website. Your Personal Message CAPTCHA This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. Share Serological and viral prevalence of Oropouche virus (OROV): A systematic review and meta-analysis from 2000-2024 including human, animal, and vector surveillance studies Emilie Toews , Sabah Shaikh , Shaila Akter , Caseng Zhang , Anabel Selemon , Rahul K Arora , Niklas Bobrovitz , Thomas Jaenisch , Mairead G Whelan , Harriet Ware medRxiv 2025.07.10.25331249; doi: https://doi.org/10.1101/2025.07.10.25331249 Share This Article: Copy Citation Tools Serological and viral prevalence of Oropouche virus (OROV): A systematic review and meta-analysis from 2000-2024 including human, animal, and vector surveillance studies Emilie Toews , Sabah Shaikh , Shaila Akter , Caseng Zhang , Anabel Selemon , Rahul K Arora , Niklas Bobrovitz , Thomas Jaenisch , Mairead G Whelan , Harriet Ware medRxiv 2025.07.10.25331249; doi: https://doi.org/10.1101/2025.07.10.25331249 Citation Manager Formats BibTeX Bookends EasyBib EndNote (tagged) EndNote 8 (xml) Medlars Mendeley Papers RefWorks Tagged Ref Manager RIS Zotero Tweet Widget Facebook Like Google Plus One Subject Area Infectious Diseases (except HIV/AIDS) Subject Areas All Articles Addiction Medicine (568) Allergy and Immunology (863) Anesthesia (300) Cardiovascular Medicine (4435) Dentistry and Oral Medicine (444) Dermatology (382) Emergency Medicine (608) Endocrinology (including Diabetes Mellitus and Metabolic Disease) (1509) Epidemiology (15229) Forensic Medicine (30) Gastroenterology (1124) Genetic and Genomic Medicine (6600) Geriatric Medicine (668) Health Economics (997) Health Informatics (4538) Health Policy (1368) Health Systems and Quality Improvement (1613) Hematology (541) HIV/AIDS (1264) Infectious Diseases (except HIV/AIDS) (15916) Intensive Care and Critical Care Medicine (1103) Medical Education (623) Medical Ethics (146) Nephrology (667) Neurology (6599) Nursing (346) Nutrition (998) Obstetrics and Gynecology (1144) Occupational and Environmental Health (957) Oncology (3333) Ophthalmology (974) Orthopedics (369) Otolaryngology (420) Pain Medicine (436) Palliative Medicine (130) Pathology (663) Pediatrics (1693) Pharmacology and Therapeutics (691) Primary Care Research (711) Psychiatry and Clinical Psychology (5447) Public and Global Health (9232) Radiology and Imaging (2198) Rehabilitation Medicine and Physical Therapy (1370) Respiratory Medicine (1196) Rheumatology (593) Sexual and Reproductive Health (712) Sports Medicine (530) Surgery (712) Toxicology (99) Transplantation (289) Urology (265) (function(){function c(){var b=a.contentDocument||a.contentWindow.document;if(b){var d=b.createElement('script');d.innerHTML="window.__CF$cv$params={r:'a00db0ff3c0faa64',t:'MTc3OTY0MDI5NA=='};var a=document.createElement('script');a.src='/cdn-cgi/challenge-platform/scripts/jsd/main.js';document.getElementsByTagName('head')[0].appendChild(a);";b.getElementsByTagName('head')[0].appendChild(d)}}if(document.body){var a=document.createElement('iframe');a.height=1;a.width=1;a.style.position='absolute';a.style.top=0;a.style.left=0;a.style.border='none';a.style.visibility='hidden';document.body.appendChild(a);if('loading'!==document.readyState)c();else if(window.addEventListener)document.addEventListener('DOMContentLoaded',c);else{var e=document.onreadystatechange||function(){};document.onreadystatechange=function(b){e(b);'loading'!==document.readyState&&(document.onreadystatechange=e,c())}}}})();