Browsing by Author "Vennervald, Birgitte J."

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    Effect of Praziquantel Treatment during Pregnancy on Cytokine Responses to Schistosome Antigens: Results of a Randomized, Placebo-Controlled Trial
    (The Journal of infectious diseases, 2008) Tweyongyere, Robert; Mawa, Patrice A.; Ngom-wegi, Sophy; Ndibazza, Juliet; Duong, Trinh; Vennervald, Birgitte J.; Dunne, David W.; Katunguka-Rwakishaya, Eli; Elliott, Alison M.
    Praziquantel treatment of schistosomiasis boosts antischistosome responses, with type 2 helper T cell bias that may contribute to immunologically mediated killing and to protection against reinfection. Praziquantel treatment during pregnancy was recommended in 2002, but the immunological effects of the treatment had not been investigated.A cohort of 387 Schistosoma mansoni-infected women were recruited from a larger trial of deworming during pregnancy. Women were randomized to receive either praziquantel or placebo during pregnancy. Six weeks after delivery, all women received praziquantel. Cytokine responses to S. mansoni worm and egg antigens were measured in whole blood culture before and 6 weeks after each treatment.Schistosome-specific cytokine responses were suppressed during pregnancy. Praziquantel treatment during pregnancy caused significant boosts in interferon-γ (IFN-γ), interleukin (IL)-2, IL-4, IL-5, IL-13, and IL-10 responses to schistosome worm antigen and in IFN-γ, IL-5, and IL-13 responses to schistosome egg antigen, but these boosts were not as substantial as those seen for women treated after delivery.Pregnancy suppresses a potentially beneficial boost in cytokine responses associated with praziquantel treatment. Further studies are needed on the long-term effects that treatment of schistosomiasis during pregnancy have on morbidity and resistance to reinfection among treated women and their offspring.
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    Effect of praziquantel treatment of Schistosoma mansoni during pregnancy on intensity of infection and antibody responses to schistosome antigens: results of a randomised, placebo-controlled trial
    (BMC Infectious Diseases, 2009) Tweyongyere, Robert; Mawa, Patrice A.; Emojong, Nicholas O.; Mpairwe, Harriet; Jones, Frances M.; Duong, Trinh; Dunne, David W.; Vennervald, Birgitte J.; Katunguka-Rwakishaya, Eli; Elliott, Alison M.
    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 Schistosoma mansoni during pregnancy, compared with treatment after delivery.A nested cohort of 387 Schistosoma mansoni 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 S. mansoni worm and egg antigens were measured by ELISA. Results were compared between women first treated during pregnancy and women first treated after delivery.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 S. mansoni. At six weeks after praziquantel treatment during pregnancy S. mansoni 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.S mansoni 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.