The Accuracy of Praziquantel Dose Poles for Mass Treatment of Schistosomiasis in School Girls in KwaZulu-Natal, South Africa

<div><p>Background</p><p>More than 260 million people live with schistosomiasis and regular mass-treatment should be implemented to prevent morbidity. Praziquantel, dosed at 40 milligrams per kilogram bodyweight, is the drug of choice. During the last decades the WHO Tablet Pole–which estimates tablet need by height as representing weight–has been used as a practical and cheap tool in mass treatment. In South Africa this method could be inaccurate given the prevalence of overweight and obesity. In this study in female pupils in KwaZulu-Natal, South Africa, we explored the accuracy of the WHO Tablet Pole and the recently developed Modified Dose Pole for adults with two additional intervals and correction for body mass index (BMI).</p><p>Methodology</p><p>In randomly selected primary and secondary schools of schistosomiasis-endemic areas, height and weight of female pupils were measured. The WHO Tablet Pole and Modified Dose Pole were used to indicate the amount of praziquantel according to height and the dose in milligrams per kilogram bodyweight was calculated. The BMI correction was performed by adding 600 milligrams (1 tablet) to the indicated dose if a person was overweight/obese.</p><p>Principal Findings</p><p>3157 female students were investigated and 35% were found to be overweight/obese. Using the WHO Tablet Pole, 73% would have received an adequate dose (range 30–60 mg/kg). When correcting for BMI, this would have been 94%. Using the Modified Dose Pole with BMI correction, 97% would have been adequately treated.</p><p>Conclusions</p><p>This study shows that the WHO Tablet Pole will be inaccurate in estimating the dose of praziquantel in South African girls due to high prevalence of overweight/obesity. Under-dosing of individuals who appear overweight/obese could be largely prevented by adding an extra praziquantel tablet to the recommended dose. Further research must be done to explore if subjective weight estimates are reliable.</p></div

Image analysis of female genital schistosomiasis of the uterine cervix.

<p><b>A.</b> The original colour image. Note that there is a light reflection at 6 o'clock and parts of the speculum can be seen on the right hand side (artefacts). These were removed automatically in the image processing. <b>B.</b> The product of multiplying the inverted "green channel" (from the "Red-Green-Blue" (RGB) colour space with the "saturation channel" (from the "Hue-Saturation-Value" (HSV) colour space). <b>C.</b> The region of interest (ROI) of image B with all pixels below the mean grey value removed. <b>D.</b> The result of convolution of the circular template and image C. The darker areas represent higher degrees of roundness. <b>E.</b> The result of adaptive local thresholding of image B using a modified Niblack method. <b>F.</b> The final output image automatically generated by the image analysis. It shows the ectocervix with numerous abnormal blood vessels (black skeleton) and the centres of circular structures identified by template matching (yellow dots).</p

Characteristics of subjects (N = 1330).

<p>Characteristics of subjects (N = 1330).</p

The weight range for the WHO Tablet Pole height intervals.

<p>All individuals in one interval would have received the same number of praziquantel tablets.</p

Flow chart enrollment of participants.

<p>Flow chart enrollment of participants.</p

The relationship between body mass index and dose received using the WHO Tablet Pole.

<p>The increase in tablet interval (from ½ tablet to 1) at a height of 160 cm appears as a gap in the study population. The horizontal lines present the range of an appropriate praziquantel dose between 30–60 mg/kg.</p

The cost of weight scales for mass treatment in schools in the KwaZulu-Natal Province.

<p>The cost of weight scales for mass treatment in schools in the KwaZulu-Natal Province.</p

<em>S. haematobium</em> as a Common Cause of Genital Morbidity in Girls: A Cross-sectional Study of Children in South Africa

<div><p>Background</p><p><i>Schistosoma (S.) haematobium</i> infection is a common cause of genital morbidity in adult women. Ova in the genital mucosal lining may cause lesions, bleeding, pain, discharge, and the damaged surfaces may pose a risk for HIV. In a heterogeneous schistosomiasis endemic area in South Africa, we sought to investigate if young girls had genital symptoms and if this was associated with urinary <i>S. haematobium</i>.</p> <p>Methodology</p><p>In a cross-sectional study of 18 randomly chosen primary schools, we included 1057 schoolgirls between the age of 10 and 12 years. We interviewed assenting girls, whose parents had consented to their participation and examined three urines from each of them for schistosome ova.</p> <p>Principal findings</p><p>One third of the girls reported to have a history of genital symptoms. Prior schistosomal infection was reported by 22% (226/1020), this was associated with current genital symptoms (p<0.001). In regression analysis the genital symptoms were significantly associated both with urinary schistosomiasis (p<0.001) and water contact (p<0.001).</p> <p>Conclusions</p><p>Even before sexually active age, a relatively large proportion of the participating girls had similar genital symptoms to those reported for adult genital schistosomiasis previously. Anti-schistosomal treatment should be considered at a young age in order to prevent chronic genital damage and secondary infections such as HIV, sexually transmitted diseases and other super-infections.</p> </div

Results of medical doctor disability assessment for children screened by TQ.

<p>Results of medical doctor disability assessment for children screened by TQ.</p

Dosages of praziquantel that would have been administered using the WHO Tablet Pole and the Modified Dose Pole (with and without BMI correction) in a population of 3157 female students of primary and secondary schools in South Africa.

<p>Dosages of praziquantel that would have been administered using the WHO Tablet Pole and the Modified Dose Pole (with and without BMI correction) in a population of 3157 female students of primary and secondary schools in South Africa.</p