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

Introduction

The Oropouche virus (OROV) is an emerging arbovirus that threatens the Amazon region of Brazil, Peru, and Venezuela¹. The coexistence of this pathogen with other long-term circulating arboviruses, such as dengue virus (DENV), West Nile virus (WNV), Venezuelan Equine Encephalitis (VEEV) and yellow fever virus (YFV), as well as emerging arboviruses such as chikungunya (CHIKV), Zika (ZIKV) and Mayaro virus (MAYV), may hinder clinical diagnosis and successful vector-control strategies². Research is essential to be able to manage this complex scenario. As has been highlighted by Ballabeni and Boggio³, 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 and Medline (via GoPubMed®).

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. Searches were done from May 30 to June 30, 2015.

Data was tabulated and analyzed in Excel 2007® for Windows 7® (Dataset 1⁴), summarizing quantitative variables with means and interquartile ranges (IQRs), and qualitative variables with proportions.

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).

Figure 1. Graphical representation of major international research networks involved in research on Oropouche (via GoPubMed®) and research trends from 1970 to 2015.

For Scopus, the annual average number of articles published up to 2014 was 5 (IQR: 1–17) (Figure 2). In June 2015, only two articles had been published that year. Nevertheless, after 1996, although not uniform, there was an increasing trend in the number of articles published on OROV per year, reaching 9 in 2011 (Figure 2). At Scopus 19 countries contributed to the publication of at least 1 paper during the study period (Figure 3). For SCI-E, the annual average number of articles published up to 2014 was 6.2 (IQR: 1–20), with 16 countries contributing to the publication of at least 1 paper during the study period (Figure 4).

Figure 2. Research trends on Oropouche virus from 1960 to 2016.

Data taken from Scopus.

Figure 3. Research on Oropouche virus, ranked by contributing countries (%).

Data taken from Scopus.

Figure 4. Research on Oropouche virus, ranked by contributing countries (%).

Data taken from SCI-E.

“Universidade de Sao Paulo” in Sao Paulo, Brazil, was the institution with the most prolific research contribution, and “Figueiredo, L.T.M” was the author with the longest record in Oropouche research, with 12 articles (Figure 1 and Figure 2). The greatest H-indexes for Oropouche issues came from Brazil (H-index=12, 431 citations), the United States of America (H-index=10, 339 citations), Peru (H-index=9, 234 citations), United Kingdom (H-index=6, 144 citations), Canada (H-index=5, 155 citations) and Trinidad and Tobago (H-index=4, 92 citations).

Discussion

OROV outbreaks increase when the rainy season starts (January to June) in endemic areas, where the population density of Culicoides paraensis is high¹. In fact, the OROV dispersion routes and its genetic diversity⁵ 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 fever⁶. 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 cases⁶. 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 challenge¹⁰, 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.

In conclusion, Brazil is leading the initiative on OROV research. 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.

Data availability

Dataset 1: Raw data obtained from bibliographical databases (Medline, Scopus and SCI-E).

DOI, 10.5256/f1000research.10936.d152949⁴