Analysis of Zika virus neutralizing antibodies in normal healthy Thais

Sornjai, Wannapa; Jaratsittisin, Janejira; Auewarakul, Prasert; Wikan, Nitwara; Smith, Duncan R.

doi:10.1038/s41598-018-35643-6

“…10 Our results, combined with those from a survey among healthy Thais in Central Thailand (seroprevalence of 70.4%), suggest that this Thai population were only partially protected by the antibody. 20 These levels of immunity may explain the low but sustained level of ZIKV transmission in Thailand as proposed by previous authors (Ruchusatsawat et al, 2019). 28 Our results showed that older age is associated with seropositivity.…”

Section: Discussionmentioning

confidence: 65%

“…ZIKV was believed to be endemic in the Southeast Asia region for many years. 12,20,26,27 However, regardless of the nature of the source, one-half to one-third of the population are at risk of infection.…”

Section: Discussionmentioning

confidence: 99%

“…A neutralization titer ≥ 1:10 by PRNT50 was considered as a seropositive. 19,20 Random samples of 10 positive (titers > 1:160) and 10 negative (titer < 1:10) serum samples were used to further test for neutralizing antibody against dengue virus (DENV) serotype 1-4 (strain 16007,16681 16562, and C036/06 respectively) and Japanese encephalitis virus (Beijing strain).…”

Section: Laboratory Testsmentioning

confidence: 99%

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Survey on neutralizing antibodies against Zika virus eighteen months post-outbreak in two southern Thailand communities

Densathaporn

¹

,

Sangthong

²

,

Sakolnapa

³

et al. 2020

Preprint

1

0

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Background In 2016 and 2017, Zika virus (ZIKV) infection outbreaks occurred in two communities in southern Thailand. This re-immerging infection can widely spread by mosquito bites and cause serious complications in a central nervous system, especially in babies. Thus they should be protected. This study aims to (1) To determine the prevalence of neutralizing ZIKV antibodies in the post-outbreak areas among the general population and pregnancy women residing at various distances from the houses of the nearest index patients; (2) To examine the cross-neutralizing capacity of antibodies against ZIKV on other flaviviruses commonly found in the study areas; (3) To identify factors associated with the presence of neutralizing ZIKV antibodies. Methods The two post-outbreak communities were visited at 18 months after the outbreaks. We enrolled (1) 18 confirmed ZIKV infected (index) cases, (2) sample of 554 neighbors in the outbreak areas who lived at various distances from the index patients’ houses, (3) 190 residents of non-outbreak areas, and (4) all pregnant women regardless of gestational age residing in the study areas (n = 805). All serum specimens underwent the plaque reduction neutralization test (PRNT). Ten randomly selected ZIKV seropositive and ten randomly selected seronegative specimens were tested for dengue virus serotypes 1-4 (DENV1-4) and Japanese encephalitis virus (JEV) antibodies using PRNT. Serum titer above 1:10 was considered positive. Multiple logistic regression was used to assess factors associated with seropositivity. Results Out of all 18 index cases, 17 remained seropositive. The seroprevalence (95% CI) in the two outbreak areas were 66.5% (59.1-73.9%) and 45.6% (38.8-52.5%) in general population, and 41.0% (36.1-46.0%) and 23.5% (19.4-21.9%) in pregnant women. Multivariate analysis showed that seropositivity was independent of the distance gradient from the index’s houses. However, being elderly, poorly educated, and living far from a plantation was associated with seropositivity. DENV1-4 and JEV neutralizing antibodies were present in nearly all ZIKV-positive and negative subsamples. Conclusion Protective herd immunity for ZIKV infection is inadequate, especially among pregnant women in the two post-outbreak areas in southern Thailand.

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“…10 Our results, combined with those from a survey among healthy Thais in Central Thailand (seroprevalence of 70.4%[PRNT50≥10] and 20.2%[PRNT90≥20]), suggest that this Thai population were only partially protected by the antibody. 24 These levels of immunity may explain the low but sustained level of ZIKV transmission in Thailand as proposed by previous authors (Ruchusatsawat et al, 2019). 33 Our results showed that older age is associated with seropositivity.…”

Section: Discussionmentioning

confidence: 65%

Survey on neutralizing antibodies against Zika virus eighteen months post-outbreak in two southern Thailand communities

Densathaporn

¹

,

Sangthong

²

,

Sakolnapa

³

et al. 2020

Preprint

0

View full text Add to dashboard Cite

Background: In 2016 and 2017, Zika virus (ZIKV) infection outbreaks occurred in two communities in southern Thailand. This re-immerging infection can widely spread by mosquito bites and cause serious complications in a central nervous system among children born to infected mothers. Thus, they should be protected. This study aims to (1) To determine the prevalence of neutralizing ZIKV antibodies in the post-outbreak areas among the general population and pregnancy women residing at various distances from the houses of the nearest index patients; (2) To examine the cross-neutralizing capacity of antibodies against ZIKV on other flaviviruses commonly found in the study areas; (3) To identify factors associated with the presence of neutralizing ZIKV antibodies.Methods: The two post-outbreak communities were visited at 18 months after the outbreaks. We enrolled (1) 18 confirmed ZIKV infected (index) cases, (2) sample of 554 neighbors in the outbreak areas who lived at various distances from the index patients’ houses, (3) 190 residents of non-outbreak areas, and (4) all pregnant women regardless of gestational age residing in the study areas (n = 805). All serum specimens underwent the plaque reduction neutralization test (PRNT). Ten randomly selected ZIKV seropositive and ten randomly selected seronegative specimens were tested for dengue virus serotypes 1-4 (DENV1-4) and Japanese encephalitis virus (JEV) antibodies using PRNT90. Serum titer above 1:10 was considered positive. Multiple logistic regression was used to assess factors associated with seropositivity.Results: Out of all 18 index cases, 9 remained seropositive. The seroprevalence (95% CI) in the two outbreak areas were 43.7% (35.9-51.6%) and 29.7% (23.3-36.0%) in general population, and 24.3% (20.1-28.8%) and 12.8% (9.7-16.5%) in pregnant women. Multivariate analysis showed that seropositivity was independent of the distance gradient from the index’s houses. However, being elderly was associated with seropositivity. DENV1-4 and JEV neutralizing antibodies were present in most ZIKV-positive and negative subsamples.Conclusion: Protective herd immunity for ZIKV infection is inadequate, especially among pregnant women in the two post-outbreak areas in southern Thailand.

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“…A neutralization titer ≥1:10 by PRNT90 was considered as a seropositive. 23,24 Random samples of 10 positive (PRNT90 titers> 1:10) and 10 negative (PRNT90 titer < 1:10) serum samples were used to further test for neutralizing antibody against dengue virus (DENV) serotype 1-4…”

Section: Laboratory Testsmentioning

confidence: 99%

Survey on neutralizing antibodies against Zika virus eighteen months post-outbreak in two southern Thailand communities

Densathaporn

¹

,

Sangthong

²

,

Sakolnapa

³

et al. 2020

Preprint

0

View full text Add to dashboard Cite

Background: In 2016 and 2017, Zika virus (ZIKV) infection outbreaks occurred in two communities in southern Thailand. This re-immerging infection can widely spread by mosquito bites and cause serious complications in a central nervous system among children born to infected mothers. Thus, they should be protected. This study aims to (1) To determine the prevalence of neutralizing ZIKV antibodies in the post-outbreak areas among the general population and pregnancy women residing at various distances from the houses of the nearest index patients; (2) To examine the cross-neutralizing capacity of antibodies against ZIKV on other flaviviruses commonly found in the study areas; (3) To identify factors associated with the presence of neutralizing ZIKV antibodies.Methods: The two post-outbreak communities were visited at 18 months after the outbreaks. We enrolled (1) 18 confirmed ZIKV infected (index) cases, (2) sample of 554 neighbors in the outbreak areas who lived at various distances from the index patients’ houses, (3) 190 residents of non-outbreak areas, and (4) all pregnant women regardless of gestational age residing in the study areas (n = 805). All serum specimens underwent the plaque reduction neutralization test (PRNT). Ten randomly selected ZIKV seropositive and ten randomly selected seronegative specimens were tested for dengue virus serotypes 1-4 (DENV1-4) and Japanese encephalitis virus (JEV) antibodies using PRNT90. Serum titer above 1:10 was considered positive. Multiple logistic regression was used to assess factors associated with seropositivity.Results: Out of all 18 index cases, 9 remained seropositive. The seroprevalence (95% CI) in the two outbreak areas were 43.7% (35.9-51.6%) and 29.7% (23.3-36.0%) in general population, and 24.3% (20.1-28.8%) and 12.8% (9.7-16.5%) in pregnant women. Multivariate analysis showed that seropositivity was independent of the distance gradient from the index’s houses. However, being elderly was associated with seropositivity. DENV1-4 and JEV neutralizing antibodies were present in most ZIKV-positive and negative subsamples.Conclusion: Protective herd immunity for ZIKV infection is inadequate, especially among pregnant women in the two post-outbreak areas in southern Thailand.

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Analysis of Zika virus neutralizing antibodies in normal healthy Thais

Cited by 22 publications

References 57 publications

Survey on neutralizing antibodies against Zika virus eighteen months post-outbreak in two southern Thailand communities

Survey on neutralizing antibodies against Zika virus eighteen months post-outbreak in two southern Thailand communities

Survey on neutralizing antibodies against Zika virus eighteen months post-outbreak in two southern Thailand communities

Survey on neutralizing antibodies against Zika virus eighteen months post-outbreak in two southern Thailand communities

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