Effect of praziquantel treatment of <it>Schistosoma mansoni </it>during pregnancy on intensity of infection and antibody responses to schistosome antigens: results of a randomised, placebo-controlled trial

<p>Abstract</p> <p>Background</p> <p>Praziquantel treatment of schistosomiasis during pregnancy was only recommended in 2002; hence the effects of treatment during pregnancy are not fully known. We have therefore evaluated the effects on infection intensity and the immunological effects of praziquantel treatment against <it>Schistosoma mansoni </it>during pregnancy, compared with treatment after delivery.</p> <p>Methods</p> <p>A nested cohort of 387 <it>Schistosoma mansoni </it>infected women was recruited within a larger trial of de-worming during pregnancy. Women were randomised to receive praziquantel or placebo during pregnancy. All women were treated after delivery. Infection intensity after treatment was assessed by a single Kato-Katz examination of stool samples with duplicate slides and categorised as undetected, light (1–99 eggs per gram (epg)), moderate (100–399 epg) or heavy (≥400 epg). Antibodies against <it>S. mansoni </it>worm and egg antigens were measured by ELISA. Results were compared between women first treated during pregnancy and women first treated after delivery.</p> <p>Results</p> <p>At enrolment, 252 (65.1%) of the women had light infection (median (IQR) epg: 35 (11, 59)), 75 (19.3%) moderate (median (IQR) epg: 179(131, 227)) and 60 (15.5%) had heavy infection (median (IQR) epg: 749 (521, 1169)) with <it>S. mansoni</it>. At six weeks after praziquantel treatment during pregnancy <it>S. mansoni </it>infection was not detectable in 81.9% of the women and prevalence and intensity had decreased to 11.8% light, 4.7% moderate and 1.6% heavy a similar reduction when compared with those first treated after delivery (undetected (88.5%), light (10.6%), moderate (0.9%) and heavy (0%), p = 0.16). Parasite specific antibody levels were lower during pregnancy than after delivery. Praziquantel treatment during pregnancy boosted anti-worm IgG isotypes and to a lesser extent IgE, but these boosts were less pronounced than in women whose treatment was delayed until after delivery. Praziquantel had limited effects on antibodies against egg antigens.</p> <p>Conclusion</p> <p><it>S mansoni </it>antigen-specific antibody levels and praziquantel-induced boosts in antibody levels were broadly suppressed during pregnancy, but this was not associated with major reduction in the efficacy of praziquantel. Long-term implications of these findings in relation to resistance to re-infection remain to be explored.</p> <p>Trial registration</p> <p>International Standard Randomised Controlled Trial Number for the current study: ISRCTN32849447 <url>http://www.controlled-trials.com/ISRCTN32849447/elliott</url></p>

Abstract licence: CC BY-NC-ND

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