title: Community Rates of IgG4 Antibodies to Ascaris Haemoglobin Reflect Changes in Community Egg Loads Following Mass Drug Administration.
abstract: BACKGROUND
  Conventional diagnostic methods for human ascariasis are based on the detection of Ascaris lumbricoides eggs in stool samples. However, studies of ascariasis in pigs have shown that the prevalence and the number of eggs detected in the stool do not correlate well with exposure of the herd to the parasite. On the other hand, an ELISA test measuring antibodies to Ascaris suum haemoglobin (AsHb) has been shown to be useful for estimating transmission intensity on pig farms. In this study, we further characterized the AsHb antigen and screened samples from a population-based study conducted in an area that is endemic for Ascaris lumbricoides in Indonesia to assess changes in AsHb antibody rates and levels in humans following mass drug administration (MDA).
  
  
  RESULTS
  We developed and evaluated an ELISA to detect human IgG4 antibodies to AsHb. We tested 1066 plasma samples collected at different times from 599 subjects who lived in a village in rural Indonesia that was highly endemic for ascariasis. The community received 6 rounds of MDA for lymphatic filariasis with albendazole plus diethylcarbamazine between 2002 and 2007. While the AsHb antibody assay was not sensitive for detecting all individuals with Ascaris eggs in their stools, the percentage of seropositive individuals decreased rapidly following MDA. Reductions in antibody rates reflected decreased mean egg output per person both at the community level and in different age groups. Two years after the last round of MDA the community egg output and antibody prevalence rate were reduced by 81.6% and 78.9% respectively compared to baseline levels.
  
  
  CONCLUSIONS
  IgG4 antibody levels to AsHb appear to reflect recent exposure to Ascaris. The antibody prevalence rate may be a useful indicator for Ascaris transmission intensity in communities that can be used to assess the impact of control measures on the force of transmission.
authors.affiliation: Infectious Diseases Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America.
authors.forename: Johnny
authors.initials: J
authors.lastname: Vlaminck
authors.affiliation: Department of Parasitology, Faculty of Medicine, University of Indonesia, Jakarta, Indonesia.
authors.forename: Taniawati
authors.initials: T
authors.lastname: Supali
authors.affiliation: Laboratory for Parasitology, Department of Virology, Parasitology and Immunology, Ghent University, Merelbeke, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Geldhof
authors.affiliation: Department of Parasitology, Center for Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Cornelis H
authors.initials: CH
authors.lastname: Hokke
authors.affiliation: Infectious Diseases Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America.
authors.forename: Peter U
authors.initials: PU
authors.lastname: Fischer
authors.affiliation: Infectious Diseases Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America.
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Weil
mesh_terms: D015766:Albendazole / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000627:therapeutic use; D000909:Antibodies, Helminth / Q000097:blood*; D001196:Ascariasis / Q000188:drug therapy* / Q000276:immunology / Q000469:parasitology; D017164:Ascaris lumbricoides / Q000276:immunology*; D015153:Blotting, Western; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification; D018509:DNA, Helminth / Q000302:isolation & purification; D004049:Diethylcarbamazine / Q000008:administration & dosage / Q000494:pharmacology; D005243:Feces / Q000469:parasitology; D006454:Hemoglobins / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000302:isolation & purification*; D010063:Ovum; D010270:Parasite Egg Count; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism
chemical_list: D000871:Anthelmintics; D000909:Antibodies, Helminth; D018076:DNA, Complementary; D018509:DNA, Helminth; D006454:Hemoglobins; D007074:Immunoglobulin G; D011134:Polysaccharides; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D015766:Albendazole; D004049:Diethylcarbamazine