Research Article: Dengue and chikungunya seroprevalence among Qatari nationals and immigrants residing in Qatar

Date Published: January 31, 2019

Publisher: Public Library of Science

Author(s): John M. Humphrey, Enas S. Al-Absi, Munia M. Hamdan, Sara S. Okasha, Diyna M. Al-Trmanini, Hend G. El-Dous, Soha R. Dargham, John Schieffelin, Laith J. Abu-Raddad, Gheyath K. Nasrallah, Abdallah M. Samy.

http://doi.org/10.1371/journal.pone.0211574

Abstract

The objective of this study is to characterize the seroprevalence of anti-dengue (DENV) and anti-chikungunya (CHIKV) antibodies among blood donors residing in Qatar who are Middle East and North Africa (MENA) nationals and non-nationals. Sera were collected from adult blood donors in Qatar from 2013 to 2016 and tested for anti-DENV and anti-CHIKV IgG using commercial microplate enzyme-linked immunosorbent assays. Age-specific seroprevalence was summarized by region/nationality: Asia (India, Philippines), Middle East (Iran, Jordan, Lebanon, Pakistan, Palestine, Syria, Yemen), North Africa (Egypt, Sudan), Qatar. The adjusted odds of anti-DENV and anti-CHIKV IgG seropositivity was estimated by logistic regression. Among 1,992 serum samples tested, Asian nationals had higher adjusted odds of being seropositive for anti-DENV antibodies compared to nationals of the Middle East (aOR 0.05, 95% CI 0.04–0.07), North Africa (aOR 0.14, 95% CI 0.10–0.20), and Qatar (aOR 0.01, 95% CI 0.01–0.03). Asian nationals also had higher adjusted odds of being seropositive for anti-CHIKV antibodies compared to those from the Middle East (aOR 0.14, 95% CI 0.07–0.27), North Africa (aOR 0.50, 95% CI 0.26–0.96), and Qatar (aOR 0.38, 95% CI 0.15–0.96). The adjusted odds of being anti-DENV seropositive was higher among anti-CHIKV seropositive adults, and vice versa (aOR 1.94, 95% CI 1.09–3.44), suggesting co-circulation of these viruses. DENV and CHIKV exposure is lower in Qatar and MENA nationals compared to Asian nationals suggesting a lower burden of DENV and CHIKV disease in the MENA. Antibodies to both viruses were detected in nationals from most MENA countries, supporting the need to better understand the regional epidemiology of these viruses.

Partial Text

Although dengue (DENV) and chikungunya (CHIKV) viruses rank among the most important causes of arboviral diseases in the world, their epidemiology in the Middle East and North Africa (MENA) is sparsely characterized [1, 2]. Recent outbreaks of DENV and CHIKV have been documented in several MENA countries including Pakistan, Sudan, and Yemen, while in over half of MENA countries, no seroprevalence data has ever been published [1–8]. In Qatar, neither local transmission of DENV or CHIKV, nor the presence of their principal vectors, Aedes aegypti and Aedes albopictus, has yet been reported to our knowledge. However, the expansion of DENV in neighboring Saudi Arabia and Yemen underscores the importance of understanding the epidemiology of these pathogens and their potential for spread in Qatar and the surrounding region.

A total of 1,992 serum samples from male subjects ≥ 18 years of age from 12 countries were tested for anti-DENV and anti-CHIKV IgG antibodies (Fig 1 and Table 1). The number of samples tested per country ranged from 97 (< 100 due to insufficient serum) to 200. The median [IQR] age of subjects was 36 [30–43] years. Anti-DENV IgG was detected in six or more samples from individuals from every country, while anti-CHIKV IgG was detected in at least one sample from individuals from every country except Iran. The country-specific overall seroprevalence for anti-DENV IgG ranged from 3.5% (95% CI 1.6–6.8%) in Qatar to 95.8% (95% CI 91.0–98.4%) in the Philippines. For anti-CHIKV IgG, overall seroprevalence ranged from 0% in Iran to 17.7% (95% CI 11.6–25.2%) in the Philippines. In our study, anti-DENV and anti-CHIKV IgG prevalences were significantly lower among blood donors residing in Qatar who were MENA nationals compared to Asian nationals, though antibodies to both viruses were detected from donors in all regions. This finding underscores the need to better understand the distribution and epidemiology of these pathogens in the MENA region, but it suggests that the overall burden of DENV and CHIKV disease is higher in India and the Philippines than in the MENA countries represented in our study. The results also suggest regional variability within the MENA region. Exposure to DENV and CHIKV is low among Qatar and other MENA nationals compared to Asian nationals, suggesting a lower burden of DENV and CHIKV disease in the MENA countries. Antibodies to both viruses were detected in nationals from all MENA countries except Iran, supporting the need for further research to understand the epidemiology of DENV and CHIKV, and the co-circulating viruses that cause serologic cross-reactions, in the MENA. The findings in our study do not support the need for travellers to Qatar to take measures to prevent DENV and CHIKV infections while in Qatar. Surveillance for Ae. aegypti and Ae. albopictus should be implemented in countries in which autochthonous transmission of DENV or CHIKV has not yet been reported.   Source: http://doi.org/10.1371/journal.pone.0211574

 

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