Serological measures to assess the efficacy of malaria control programme on Ambae Island, Vanuatu

Zulkarnain Md Idris, Chim W. Chan, Mubasher Mohammed, Morris Kalkoa, George Taleo, Klara Junker, Bruno Arcà, Chris Drakeley, Akira Kaneko

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Background: Seroepidemiology can provide evidence for temporal changes in malaria transmission and is an important tool to evaluate the effectiveness of control interventions. During the early 2000s, Vanuatu experienced an acute increase in malaria incidence due to a lapse in funding for vector control. After the distribution of subsidised insecticide-treated nets (ITNs) resumed in 2003, malaria incidence decreased in the subsequent years. This study was conducted to find the serological evidence supporting the impact of ITN on exposure to Anopheles vector bites and parasite prevalence. Methods: On Ambae Island, blood samples were collected from 231 and 282 individuals in 2003 and 2007, respectively. Parasite prevalence was determined by microscopy. Antibodies to three Plasmodium falciparum (PfSE, PfMSP-119, and PfAMA-1) and three Plasmodium vivax (PvSE, PvMSP-119, and PvAMA-1) antigens, as well as the Anopheles-specific salivary antigen gSG6, were detected by ELISA. Age-specific seroprevalence was analysed using a reverse catalytic modelling approach to estimate seroconversion rates (SCRs). Results: Parasite rate decreased significantly (P < 0.001) from 19.0% in 2003 to 3.2% in 2007, with a shift from P. falciparum predominance to P. falciparum-P. vivax co-dominance. Significant (P < 0.001) decreases were observed in seroprevalence to all three P. falciparum antigens but only two of three P. vivax antigens (except PvAMA-1; P = 0.153), consistent with the more pronounced decrease in P. falciparum prevalence. Seroprevalence to gSG6 also decreased significantly (P < 0.001), suggesting that reduced exposure to vector bites was important to the decrease in parasite prevalence between 2003 and 2007. Analyses of age-specific seroprevalence showed a three-fold decrease in P. falciparum transmission, but the evidence for the decrease in P. vivax transmission was less clear. Conclusions: Serological markers pointed to the effectiveness of ITNs in reducing malaria prevalence on Ambae Island between 2003 and 2007. The recombinant gSG6 antigen originally developed to indicate exposure to the Afrotropical vector An. gambiae may be used in the Pacific to complement the traditional measure of entomological inoculation rate (EIR).

Original languageEnglish
Article number204
JournalParasites and Vectors
Volume10
Issue number1
DOIs
Publication statusPublished - 26 Apr 2017

Fingerprint

Vanuatu
Plasmodium falciparum
Islands
Malaria
Plasmodium vivax
Seroepidemiologic Studies
Parasites
Antigens
Insecticides
Anopheles
Bites and Stings
Incidence
Microscopy
Enzyme-Linked Immunosorbent Assay
Antibodies

Keywords

  • Anopheles
  • Island
  • ITN
  • Malaria
  • Plasmodium falciparum
  • Plasmodium vivax
  • Serology

ASJC Scopus subject areas

  • Parasitology
  • Infectious Diseases

Cite this

Serological measures to assess the efficacy of malaria control programme on Ambae Island, Vanuatu. / Md Idris, Zulkarnain; Chan, Chim W.; Mohammed, Mubasher; Kalkoa, Morris; Taleo, George; Junker, Klara; Arcà, Bruno; Drakeley, Chris; Kaneko, Akira.

In: Parasites and Vectors, Vol. 10, No. 1, 204, 26.04.2017.

Research output: Contribution to journalArticle

Md Idris, Z, Chan, CW, Mohammed, M, Kalkoa, M, Taleo, G, Junker, K, Arcà, B, Drakeley, C & Kaneko, A 2017, 'Serological measures to assess the efficacy of malaria control programme on Ambae Island, Vanuatu', Parasites and Vectors, vol. 10, no. 1, 204. https://doi.org/10.1186/s13071-017-2139-z
Md Idris, Zulkarnain ; Chan, Chim W. ; Mohammed, Mubasher ; Kalkoa, Morris ; Taleo, George ; Junker, Klara ; Arcà, Bruno ; Drakeley, Chris ; Kaneko, Akira. / Serological measures to assess the efficacy of malaria control programme on Ambae Island, Vanuatu. In: Parasites and Vectors. 2017 ; Vol. 10, No. 1.
@article{68b2d4eb70474a82a1658d955430c509,
title = "Serological measures to assess the efficacy of malaria control programme on Ambae Island, Vanuatu",
abstract = "Background: Seroepidemiology can provide evidence for temporal changes in malaria transmission and is an important tool to evaluate the effectiveness of control interventions. During the early 2000s, Vanuatu experienced an acute increase in malaria incidence due to a lapse in funding for vector control. After the distribution of subsidised insecticide-treated nets (ITNs) resumed in 2003, malaria incidence decreased in the subsequent years. This study was conducted to find the serological evidence supporting the impact of ITN on exposure to Anopheles vector bites and parasite prevalence. Methods: On Ambae Island, blood samples were collected from 231 and 282 individuals in 2003 and 2007, respectively. Parasite prevalence was determined by microscopy. Antibodies to three Plasmodium falciparum (PfSE, PfMSP-119, and PfAMA-1) and three Plasmodium vivax (PvSE, PvMSP-119, and PvAMA-1) antigens, as well as the Anopheles-specific salivary antigen gSG6, were detected by ELISA. Age-specific seroprevalence was analysed using a reverse catalytic modelling approach to estimate seroconversion rates (SCRs). Results: Parasite rate decreased significantly (P < 0.001) from 19.0{\%} in 2003 to 3.2{\%} in 2007, with a shift from P. falciparum predominance to P. falciparum-P. vivax co-dominance. Significant (P < 0.001) decreases were observed in seroprevalence to all three P. falciparum antigens but only two of three P. vivax antigens (except PvAMA-1; P = 0.153), consistent with the more pronounced decrease in P. falciparum prevalence. Seroprevalence to gSG6 also decreased significantly (P < 0.001), suggesting that reduced exposure to vector bites was important to the decrease in parasite prevalence between 2003 and 2007. Analyses of age-specific seroprevalence showed a three-fold decrease in P. falciparum transmission, but the evidence for the decrease in P. vivax transmission was less clear. Conclusions: Serological markers pointed to the effectiveness of ITNs in reducing malaria prevalence on Ambae Island between 2003 and 2007. The recombinant gSG6 antigen originally developed to indicate exposure to the Afrotropical vector An. gambiae may be used in the Pacific to complement the traditional measure of entomological inoculation rate (EIR).",
keywords = "Anopheles, Island, ITN, Malaria, Plasmodium falciparum, Plasmodium vivax, Serology",
author = "{Md Idris}, Zulkarnain and Chan, {Chim W.} and Mubasher Mohammed and Morris Kalkoa and George Taleo and Klara Junker and Bruno Arc{\`a} and Chris Drakeley and Akira Kaneko",
year = "2017",
month = "4",
day = "26",
doi = "10.1186/s13071-017-2139-z",
language = "English",
volume = "10",
journal = "Parasites and Vectors",
issn = "1756-3305",
publisher = "BioMed Central",
number = "1",

}

TY - JOUR

T1 - Serological measures to assess the efficacy of malaria control programme on Ambae Island, Vanuatu

AU - Md Idris, Zulkarnain

AU - Chan, Chim W.

AU - Mohammed, Mubasher

AU - Kalkoa, Morris

AU - Taleo, George

AU - Junker, Klara

AU - Arcà, Bruno

AU - Drakeley, Chris

AU - Kaneko, Akira

PY - 2017/4/26

Y1 - 2017/4/26

N2 - Background: Seroepidemiology can provide evidence for temporal changes in malaria transmission and is an important tool to evaluate the effectiveness of control interventions. During the early 2000s, Vanuatu experienced an acute increase in malaria incidence due to a lapse in funding for vector control. After the distribution of subsidised insecticide-treated nets (ITNs) resumed in 2003, malaria incidence decreased in the subsequent years. This study was conducted to find the serological evidence supporting the impact of ITN on exposure to Anopheles vector bites and parasite prevalence. Methods: On Ambae Island, blood samples were collected from 231 and 282 individuals in 2003 and 2007, respectively. Parasite prevalence was determined by microscopy. Antibodies to three Plasmodium falciparum (PfSE, PfMSP-119, and PfAMA-1) and three Plasmodium vivax (PvSE, PvMSP-119, and PvAMA-1) antigens, as well as the Anopheles-specific salivary antigen gSG6, were detected by ELISA. Age-specific seroprevalence was analysed using a reverse catalytic modelling approach to estimate seroconversion rates (SCRs). Results: Parasite rate decreased significantly (P < 0.001) from 19.0% in 2003 to 3.2% in 2007, with a shift from P. falciparum predominance to P. falciparum-P. vivax co-dominance. Significant (P < 0.001) decreases were observed in seroprevalence to all three P. falciparum antigens but only two of three P. vivax antigens (except PvAMA-1; P = 0.153), consistent with the more pronounced decrease in P. falciparum prevalence. Seroprevalence to gSG6 also decreased significantly (P < 0.001), suggesting that reduced exposure to vector bites was important to the decrease in parasite prevalence between 2003 and 2007. Analyses of age-specific seroprevalence showed a three-fold decrease in P. falciparum transmission, but the evidence for the decrease in P. vivax transmission was less clear. Conclusions: Serological markers pointed to the effectiveness of ITNs in reducing malaria prevalence on Ambae Island between 2003 and 2007. The recombinant gSG6 antigen originally developed to indicate exposure to the Afrotropical vector An. gambiae may be used in the Pacific to complement the traditional measure of entomological inoculation rate (EIR).

AB - Background: Seroepidemiology can provide evidence for temporal changes in malaria transmission and is an important tool to evaluate the effectiveness of control interventions. During the early 2000s, Vanuatu experienced an acute increase in malaria incidence due to a lapse in funding for vector control. After the distribution of subsidised insecticide-treated nets (ITNs) resumed in 2003, malaria incidence decreased in the subsequent years. This study was conducted to find the serological evidence supporting the impact of ITN on exposure to Anopheles vector bites and parasite prevalence. Methods: On Ambae Island, blood samples were collected from 231 and 282 individuals in 2003 and 2007, respectively. Parasite prevalence was determined by microscopy. Antibodies to three Plasmodium falciparum (PfSE, PfMSP-119, and PfAMA-1) and three Plasmodium vivax (PvSE, PvMSP-119, and PvAMA-1) antigens, as well as the Anopheles-specific salivary antigen gSG6, were detected by ELISA. Age-specific seroprevalence was analysed using a reverse catalytic modelling approach to estimate seroconversion rates (SCRs). Results: Parasite rate decreased significantly (P < 0.001) from 19.0% in 2003 to 3.2% in 2007, with a shift from P. falciparum predominance to P. falciparum-P. vivax co-dominance. Significant (P < 0.001) decreases were observed in seroprevalence to all three P. falciparum antigens but only two of three P. vivax antigens (except PvAMA-1; P = 0.153), consistent with the more pronounced decrease in P. falciparum prevalence. Seroprevalence to gSG6 also decreased significantly (P < 0.001), suggesting that reduced exposure to vector bites was important to the decrease in parasite prevalence between 2003 and 2007. Analyses of age-specific seroprevalence showed a three-fold decrease in P. falciparum transmission, but the evidence for the decrease in P. vivax transmission was less clear. Conclusions: Serological markers pointed to the effectiveness of ITNs in reducing malaria prevalence on Ambae Island between 2003 and 2007. The recombinant gSG6 antigen originally developed to indicate exposure to the Afrotropical vector An. gambiae may be used in the Pacific to complement the traditional measure of entomological inoculation rate (EIR).

KW - Anopheles

KW - Island

KW - ITN

KW - Malaria

KW - Plasmodium falciparum

KW - Plasmodium vivax

KW - Serology

UR - http://www.scopus.com/inward/record.url?scp=85018621829&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85018621829&partnerID=8YFLogxK

U2 - 10.1186/s13071-017-2139-z

DO - 10.1186/s13071-017-2139-z

M3 - Article

VL - 10

JO - Parasites and Vectors

JF - Parasites and Vectors

SN - 1756-3305

IS - 1

M1 - 204

ER -