Seroprevalence of Zika Virus in Amphawa District, Thailand, after the 2016 Pandemic

Abstract

In 2016, Zika virus (ZIKV) infection was declared a public health emergency of international concern because of the neurological consequences in babies born to infected people. Because of the mild and nonspecific symptoms, serological tests are essential in epidemiological studies. However, cross-reactive antibodies between other Flaviviridae members may complicate the interpretation of results of these tests. This study investigated the seroprevalence of ZIKV infection in Samut Songkhram in central Thailand which was affected by the Zika outbreak of 2016. Three hundred and fifty volunteers aged 5–50 years in Amphawa District, Samut Songkhram, were enrolled between April 2017 and April 2018. ZIKV nonstructural protein 1 (NS1) immunoglobulin G enzyme-linked immunosorbent assay (ELISA) was used to screen serum samples collected on the first day of enrollment and after 6 and 12 months. The seroprevalence and seroconversion of ZIKV were assessed. Cases of ZIKV seroconversion were verified as evidence of ZIKV infection by NS1 blockade-of-binding ELISA and plaque reduction neutralization test (PRNT50). ZIKV seroprevalence in Amphawa was 15.1–17.8% with no significant change over the year. The total seroconversion rate throughout the year was 7/100 person-years. The ratio of asymptomatic to symptomatic infections was 4.5:1. The cases in our study confirmed the occurrence of occult ZIKV infections in the community. These undetected infections might promote the spread of ZIKV in vulnerable groups of the community.

Seroprevalence of Zika Virus IgM Antibodies in Pregnant Woman in Nigeria

“…It should be noted that unlike the present study which provided participants with three options in this section, both Mwanyika's and Asebe's studies provided participants with only two options (yes and no). Fever with a frequency of 44.1% was the most common symptom among the participants, which is consistent with the findings of previous studies by Mathe et al (2018) [14] , Phatihattakorn et al (2021) [21] , and Sirinam et al (2022)Zika virus (ZIKV [24] . This study finding confirms previous evidence showing fever as a primary symptom of Zika virus infection.…”

Combining Immunoassays to Identify Zika Virus Infection in Dengue-Endemic Areas

“…Indirect ELISA was performed using a previously described standard protocol [ 21 , 22 ]. In brief, plates were sensitized with ZIKV NS1 (10 µg/mL or 500 ng/well), DENV 1–4 NS1 (5 µg/mL, 250 ng for each serotype or a total of 1000 ng/well), or inactivated ZIKV (MR766) in PBS buffer and incubated at 37 °C overnight.…”

Emerging and re-emerging zoonotic viral diseases in Southeast Asia: One Health challenge

“…However the first human case was confirmed in 2010 in Cambodia ( 101 ). Epidemiological data are limited, with outbreaks reported between 2016 and 2018 in Thailand (2,300 cases) ( 102 , 103 ), Singapore (458 cases) ( 26 ), and Vietnam (265 cases) ( 104 , 105 ). Studies evidence low-level circulation in the Philippines, Myanmar, Lao PDR, Cambodia, Malaysia, and Indonesia ( 101 , 102 , 106–108 ), and no data are available for Brunei and Timor-Leste ( Figure 3 ).…”