Bibliometric analysis of Oropouche research: impact on the surveillance of emerging arboviruses in Latin America

Given the emergence and reemergence of viral diseases, particularly in Latin America, we would like to provide an analysis of the patterns of research and publication on Oropouche virus (OROV). We also discuss the implications of recent epidemics in certain areas of South America, and how more clinical and epidemiological information regarding OROV is urgently needed.

Research is essential to be able to manage this complex scenario. As has been highlighted by Ballabeni and Boggio 3 , bibliometric analyses of publications on emerging and reemerging viral diseases are important as they may lead to insights on how the global scientific and health communities react to outbreaks. We aimed to conduct a bibliometric analysis of OROV research and the impact on the surveillance of emerging and re-emerging arboviruses in Latin America.

Methods
A bibliometric study was done about OROV scientific production, with a focus on Latin America. We searched in three important regional and international databases (all of them in English): Science Citation Index Expanded (SCI-E), Scopus, Medline (via GoPubMed®), LILACS, SciELO and IMBIOMED.
This search strategy used the following key words (MeSH, Medical Subject Headings): "Oropouche" AND "Latin America", "Oropouche" AND "Argentina", "Oropouche" AND "Colombia", and the same way with the rest of the Latin American countries. Also, "OROV" was used instead of Oropouche for additional searches. All study types were included (original articles, reviews, case reports, editorials) and were categorized by year, international cooperation, city and institution, journal and authors with major contribution.

Results
A total of 260 related records were retrieved in our search; from these, 97 manuscripts were recovered in Scopus (55% from Brazil, 28% from US, and 11% from Peru); 83 articles were recovered from Medline (43% from Brazil, 18% from US, and 6% from Peru) and 80 articles were recovered from SCI-E (61% from Brazil, 35% from US, and 15% from Peru) ( Table 1). As observed in Medline, publications on OROV never reached more than 3 articles per year ( Figure 1). Analyzing this database, it can be observed that Brazil has the more productive and cooperative research groups in Latin America ( Figure 1).      Finally, at IMBIOMED none results were found.

Discussion
OROV outbreaks increase when the rainy season starts (January to June) in endemic areas, where the population density of Culicoides paraensis is high 1 . In fact, the OROV dispersion routes and its genetic diversity 5 impacted on the growth of scientific publications, as well as on the international collaboration on this topic. On the 2 nd of May 2016, the Ministry of Health of Peru reported 57 cases of OROV fever 6 . Most cases originate in towns located in the northern part of the Cusco Region, which is situated in the Amazon rainforest. 79% were detected in January, with only 7% and 14% of the cases being identified in February and March, respectively. There were no fatalities and all patients have recovered following symptomatic treatment. In February 2016, a field mission to the Madre de Dios Region conducted jointly by the Ministry of Health of Peru and PAHO/WHO revealed a mixed outbreak of dengue (DENV-2) and OROV. While Madre de Dios already experienced an outbreak of OROV fever in 1994, at the time of the mission in February, this latest outbreak was of a higher magnitude, with 120 confirmed cases 6 . Cases have also been reported in other nearby countries such as Panama, Trinidad and Tobago and Brazil, and very recently in Venezuela (2016) 1,7 . It highlights the potential for expansion of OROV and other related reassortant viruses to other countries in the region, such as Colombia, Venezuela and Ecuador, amongst others in South and Central America.
Despite this epidemiological situation, research on OROV is far below the level of research on other emerging arboviruses in Latin America such as CHIKV (6,344 articles recovered) or ZIKV 8,9 . This lack of published studies does not allow evidence-based decision-making on public health policies. More clinical and epidemiological information regarding OROV is urgently needed. Especially in highly vulnerable areas, such as those where other arboviruses (CHIKV, ZIKV, DENV) are circulating because vector and climate conditions are suitable for transmission 10-13 , research on OROV deserves more incentives among institutions, so that specific laboratory tests can be designed and more knowledge on this this emerging arbovirus can be gathered properly 2,10-13 . Currently, differential diagnosis of these arboviruses (CHIKV, DENV, ZIKV, MAYV) poses a significant challenge 10 , especially in the scenario of co-circulation and/or syndemics with emerging and circulating arboviruses, or even in the scenario of co-infections 10-13 .
The current bibliometric analysis was not restricted to Latin American countries. Although this is an arbovirus that emerged in the region, there is interest from international groups to cooperate in the research on OROV from outside Latin America. Even more, Latin America can be the source of imported cases in North America and Europe, as has been happening not just with arboviral diseases 9,10 , but also with Chagas disease. When revising the bibliometric analysis to take into account such a situation, it can be seen that there are research groups outside Latin America contributing to research about this disease. Then, countries such as USA, Canada andSpain, among others, would be concerned about the potential impact of the spread of this arbovirus outside Latin America 14 .
In conclusion, Brazil is leading the initiative on OROV research. Probably this country is the main contributor since its budget for science is one of the highest in Latin America, and not necessarily because it suffers in a greater proportion of this problem. Nevertheless, OROV infection is a differential diagnosis in the Amazonas area of Brazil. Besides this, international research networks should be expanded to gain a full understanding of this arboviral disease and explore its potential expansion and impact. To do this, the epidemic dispersion, transmission cycle, molecular epidemiology, pathogenesis, and clinical features of OROV need to be studied. The present manuscript discusses an important issue in the current epidemiological scenario: the importance of arboviral diseases as a health problem worldwide. Despite the important of the recognition and knowledge of certain diseases in this group, they present quite a heterogeneous public health challenge to sanitary authorities, both as a medical problem for healthcare professions, and a risk to the health of the general populace. While dengue and, more recently, Zika and chikungunya, reached a high level of recognition, priority, "notoriety", Oropouche fever, certainly, does not appears to be part of this group. The subject of this paper is an interesting insight regarding how much Oropouche is also potentially put down as an object of study and interest of research. Additionally, it identifies where the hotspots of scientific production are, who are potential partners for scientific cooperation projects and what the main databases for bibliographic revision are. Some questions, however, must be addressed: -In the introduction, authors included West Nile, besides dengue (as an example) as a long-term circulating virus. Not in Latin America, especially if considering the South America.

Data availability
-Why not include other indicators as to the patterns of study design (review, case series, case report ...) and the journals impact factor. -It would be interesting to correlate/compare, by country and year/period, the number of described/reported cases in the papers with those reported/notified (or not) found in the official databases.
-In table 1, it would be recommended to include a "Total" in the last line and a "%" column besides "number of articles" column.
-It is potentially confusing to have "geographical representation of major international research networks" and "research trends" in the same figure (figure 1).
-As a suggestion, in the discussion there is a lot of text on a single example, at Peru. It would be more interesting and illustrative to describe the occurrence along the time of first cases and, specifically, outbreaks in Latin American countries.
I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.
-It would have been desirable to consider some regional bibliographic databases such as LILACS and IMBIOMED, and not just English-speaking ones for a best bibliometric analysis, or to indicate why they were not taken into account.
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No competing interests were disclosed. The current bibliometric analysis was not restricted to Latin American countries, although this is an arbovirus that emerged in the region, there is interest from international groups to cooperate in the research on OROV from outside Latin America. Even more, Latin America can be the source of imported cases in North America and Europe, as has been happening not just with arboviral diseases, but specially with Chagas disease. When revising in bibliometric analysis such situation, also is see that there research groups outside Latin America contributing with this disease Certainly, we agree that Brazil probably is the main contributor to the issue because its budget for science is one of the highest in Latin America, and not necessarily because it suffers in a greater proportion of this problem. Nevertheless, OROV infection is a differential diagnosis in the Amazonas area of Brazil. Finally, regard LILACS and IMBIOMED, the number of articles found in them is very limited. In the case of LILACS only 35 and at IMBIOMED none. All these comments will be considered in the revised version that will corresponds to version 2 of this manuscript to be uploaded very soon. The study is devoted to the bibliometric analysis of research published on the emerging pathogen Oropouche virus. The title of the article is totally appropriate, the abstract provides an adequate summary of the article. There is a comprehensive explanation of study design, methods and analysis used in the study. The conclusions are well balanced and justified on the basis of the results. All sufficient information is provided for replication of results described in the study.
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No competing interests were disclosed.