Multiplex serology demonstrate cumulative prevalence and spatial distribution of malaria in Ethiopia

Details

• Alternative Title:
  Malar J
• Personal Author:
  Assefa, Ashenafi ; Ali Ahmed, Ahmed ; Deressa, Wakgari ; Sime, Heven ; Mohammed, Hussein ; Kebede, Amha ; Solomon, Hiwot ; Teka, Hiwot ; Gurrala, Kevin ; Matei, Brian ; Wakeman, Brian ; Wilson, G. Glenn ; Sinha, Ipsita ; Maude, Richard J. ; Ashton, Ruth ; Cook, Jackie ; Shi, Ya Ping ; Drakeley, Chris ; von Seidlein, Lorenz ; Rogier, Eric ; Hwang, Jimee
• Description:
  Background
  
  Measures of malaria burden using microscopy and rapid diagnostic tests (RDTs) in cross-sectional household surveys may incompletely describe the burden of malaria in low-transmission settings. This study describes the pattern of malaria transmission in Ethiopia using serological antibody estimates derived from a nationwide household survey completed in 2015.
  
  Methods
  
  Dried blood spot (DBS) samples were collected during the Ethiopian Malaria Indicator Survey in 2015 from malarious areas across Ethiopia. Samples were analysed using bead-based multiplex assays for IgG antibodies for six Plasmodium antigens: four human malaria species-specific merozoite surface protein-1 19kD antigens (MSP-1) and Apical Membrane Antigen-1 (AMA-1) for Plasmodium falciparum and Plasmodium vivax. Seroprevalence was estimated by age, elevation and region. The seroconversion rate was estimated using a reversible catalytic model fitted with maximum likelihood methods.
  
  Results
  
  Of the 10,278 DBS samples available, 93.6% (9622/10,278) had valid serological results. The mean age of participants was 15.8 years and 53.3% were female. National seroprevalence for antibodies to P. falciparum was 32.1% (95% confidence interval (CI) 29.8–34.4) and 25.0% (95% CI 22.7–27.3) to P. vivax. Estimated seroprevalences for Plasmodium malariae and Plasmodium ovale were 8.6% (95% CI 7.6–9.7) and 3.1% (95% CI 2.5–3.8), respectively. For P. falciparum seroprevalence estimates were significantly higher at lower elevations (< 2000 m) compared to higher (2000–2500 m) (aOR 4.4; p < 0.01). Among regions, P. falciparum seroprevalence ranged from 11.0% (95% CI 8.8–13.7) in Somali to 65.0% (95% CI 58.0–71.4) in Gambela Region and for P. vivax from 4.0% (95% CI 2.6–6.2) in Somali to 36.7% (95% CI 30.0–44.1) in Amhara Region. Models fitted to measure seroconversion rates showed variation nationally and by elevation, region, antigen type, and within species.
  
  Conclusion
  
  Using multiplex serology assays, this study explored the cumulative malaria burden and regional dynamics of the four human malarias in Ethiopia. High malaria burden was observed in the northwest compared to the east. High transmission in the Gambela and Benishangul-Gumuz Regions and the neglected presence of P. malariae and P. ovale may require programmatic attention. The use of a multiplex assay for antibody detection in low transmission settings has the potential to act as a more sensitive biomarker.
  
  Electronic supplementary material
  
  The online version of this article (10.1186/s12936-019-2874-z) contains supplementary material, which is available to authorized users.
  
  
• Subjects:
  Adolescent Adult Aged Aged, 80 And Over Antibodies, Protozoan Child Child, Preschool Female Humans Immunoglobulin G Infant Infant, Newborn Malaria Male Middle Aged Plasmodium Prevalence Research Seroepidemiologic Studies Serologic Tests Seroprevalence Young Adult

  More +
• Source:
  Malar J. 18
• Pubmed ID:
  31331340
• Pubmed Central ID:
  PMC6647069
• Document Type:
  Journal Article
• Place as Subject:
  Ethiopia
• Volume:
  18
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:33183754e5b42cd3efec8fa53744e6670b2c79c9e1dbde74649804c1f9f1abf0
• Download URL:
  https://stacks.cdc.gov/view/cdc/87564/cdc_87564_DS1.pdf
• File Type:
  [PDF - 1.84 MB ]