Abstract:

Background: There is a growing evidence that in addition to its excellent anti-malaria properties, Artemether also exhibits activities against the immature stages of Schistosoma species which are not killed by the anti-chistosomes drug Praziquantel, however, a number of studies have evaluated the efficacy of Artemether using Kato Katz technique which has a number of limitations. The availability of point-of-care Circulating Cathodic Antigen rapid tests, offer an opportunity to further evaluate the effects of Artemether on immature stages of Schistosoma mansoni. The objective of this study was to assess the efficacy of Artemether Lumefatrine to clear Circulating Cathodic Antigen at day 28 following treatment in school aged children.

Methods: This was an intervention study characterized by two cross-sectional surveys, which enrolled children aged 2-15 years attending Kabangaja primary school, at Ilemela district, north-western Tanzania. At baseline, a single stool and urine samples were collected from each participating child and screened for S. mansoni eggs and circulating Cathodic antigens using Kato Katz technique and point-of-care circulating Cathodic antigen. In addition, a finger prick blood sample was obtained and screened for Plasmodium falciparum infection (symptomatic and asymptomatic infection) using malaria rapid diagnostic tests and think/thin Giemsa stained smears. All co-infected children were treated using either Artemether Lumefantrine or Artemether Lumefantrine plus Praziquantel. Children who will be mono-infected with either S. mansoni of P. falciparum will be treated using either Praziquantel or Artemether Lumefantrine based on the national guidelines.

Results: A total of 312 children were enrolled, of these, 49.7% (155/312) and 50.3% (157/312) were girls and boys respectively. The overall prevalence of Schistosoma mansoni was 41.6% (95% CI 36.2-47.2) and the overall arithmetic mean eggs per gram (epg) of feaces was 74.3epg (95%CI : 61.7-86.8). The age groups 11-15 years had the highest mean eggs per gram of feaces, 112.3epg (95% CI: 69.7-154.80) (F=3.25, P=0.04). Prevalence of malaria was 10.3% (32/312) and 14.1% (44/312) based on malaria rapid diagnostic tests and Giemsa stained think smears. Based on KK technique, 26.9% (18/67) of children infected with malaria parasites had positive slides for S. mansoni infection. Based on point-of-care of circulating cathodic antigens test, only the results of 60 children who tested positive for malaria were available. Of these, 98.3% (59/60) had POC-CCA positive results. Meaning, 98.3% of them were co-infected with S. mansoni and malaria. A total of 60 children who were co-infected with malaria and Schistosomiasis received either Praziquantel and Artemether Lumefantrine (n=42) and the remaining (n=18) received only Artemether Lumefantrine and followed at day 28. At day 28, children who received PZQ + ALU, 35/42 (83.3%) had KK negative slides and only 4 (16.7%) had positive KK slides, with arithmetic mean of 0.29epg (95%CI: 0.0-0.7). Based on POC-CCA, 21/42 (50%) remained with positive results and 18/42 (42.8%) had negative results. For children who received ALU alone (n=15), based on KK technique, 14/15 (93.3%) had negative KK slides. Based on POC/CCA 11/15 (73.3%) remained with positive results and only 4/15 (26.7%) had negative POC-CCA results at day 28. For children who received both PZQ +ALU, parasitological rates were 42.8% and 83.3% using POC-CCA test and KK technique respectively. The egg reduction rate was 99.8% using KK technique. For children who received ALU alone, the parasitological cure rate was 93.3% using KK technique and 26.6% using POC-CCA tests. The egg reduction rate was 99.1% using KK technique.

Conclusion: Schistosoma mansoni and malaria are co-endemic in the study setting and co-infection occurs in a proportion of school children. Parasitological cure rates measured using POC-CCA test for children treated with either ALU alone or PZQ and ALU did not exceed 50%. However, using KK technique, the cure rate was acceptable. Egg reduction rates for children treated either using ALU alone or PZQ +ALU was satisfactory based on WHO guidelines.