Serological evidence of DENV, JEV, and ZIKV among the indigenous people (Orang Asli) of Peninsular Malaysia

• Published in: Journal of medical virology Vol. 92; no. 8; pp. 956 - 962
• Main Authors: Khor, Chee‐Sieng, Mohd‐Rahim, Nurul‐Farhana, Hassan, Habibi, Tan, Kim‐Kee, Zainal, Nurhafiza, Teoh, Boon‐Teong, Sam, Sing‐Sin, Khoo, Jing‐Jing, Lee, Hai‐Yen, Lim, Yvonne Ai‐Lian, Abubakar, Sazaly
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.08.2020
• Subjects: Adult; Antibodies; Antibodies, Neutralizing - blood; Antibodies, Viral - blood; Assaying; Cross Reactions; Demographics; dengue; Dengue - epidemiology; Dengue fever; Dengue Virus - immunology; Disease control; Encephalitis; Encephalitis Virus, Japanese - immunology; Encephalitis, Japanese - epidemiology; Enzyme-Linked Immunosorbent Assay; Female; Flavivirus - immunology; Humans; IgG antibody; Immunoglobulin G; Immunoglobulin G - blood; Indigenous Peoples; infectious diseases; Japanese encephalitis; Malaysia - epidemiology; Male; Medical importance; Mosquitoes; Native peoples; Neutralization; Neutralizing; Orang Asli; Seroepidemiologic Studies; Serology; seroprevalence; Vector-borne diseases; Virology; Viruses; Young Adult; Zika; Zika virus; Zika Virus - immunology; Zika Virus Infection - epidemiology; Malaysia; Orang Asli; seroprevalence; dengue; infectious diseases; Japanese encephalitis; Zika
• ISSN: 0146-6615; 1096-9071; 1096-9071
• DOI: 10.1002/jmv.25649

Dengue virus (DENV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV) are mosquito‐borne flavivirus of medical importance in tropical countries such as Malaysia. However, much remains unknown regarding their prevalence among the underserved indigenous people (Orang Asli) living in communities in the forest fringe areas of Peninsular Malaysia. Information on the prevalence of diseases is necessary to elevate the effectiveness of disease control and preventive measures. This study aimed to determine the seroprevalence of the three major flaviviruses among the Orang Asli and investigate the association between demographic factors and seropositivities. Sampling activities were conducted in the Orang Asli villages to obtain serum samples and demographic data from consenting volunteers. The presence of DENV, JEV, and ZIKV immunoglobulin G (IgG) antibodies in the sera were examined using commercial enzyme‐linked immunosorbent assay kits. A focus reduction neutralization assay was performed to measure virus‐specific neutralizing antibodies. A total of 872 serum samples were obtained from the Orang Asli volunteers. Serological assay results revealed that DENV IgG, JEV IgG, and ZIKV IgG seropositivities among the Orang Asli were at 4.9%, 48.4%, and 13.2%, respectively. Neutralizing antibodies (FRNT50 ≥ 1:40) against JEV and ZIKV were found in 86.7% and 100.0%, respectively, out of the samples tested. Positive serology to all three viruses corresponded significantly to the age of the volunteers with increasing seropositivity in older volunteers. Findings from the study suggest that Orang Asli are at significant risk of contracting JEV and ZIKV infections despite the lack of active transmission of the viruses in the country. Highlights Indigenous people of Malaysia, locally known as Orang Asli, mostly live at the forest fringe areas of Peninsular Malaysia. Almost 50% of the Orang Asli were positive to Japanese encephalitis virus serology. Less than 5% of the Orang Asli were positive to dengue virus serology. Neutralizing antibodies against Zika virus was observed in ~13% of the Orang Asli.