Schistosoma haematobium infection and CD4+ T-cell levels: a cross-sectional study of young South African women

Abstract

Schistosoma (S.) haematobium causes urogenital schistosomiasis and has been hypothesized to adversely impact HIV transmission and progression. On the other hand it has been hypothesized that HIV could influence the manifestations of schistosomiasis. In this cross-sectional study, we explored the association between urogenital S. haematobium infection and CD4 cell counts in 792 female high-school students from randomly selected schools in rural KwaZulu-Natal, South Africa. We also investigated the association between low CD4 cell counts in HIV positive women and the number of excreted schistosome eggs in urine. Sixteen percent were HIV positive and 31% had signs of urogenital schistosomiasis (as determined by genital sandy patches and / or abnormal blood vessels on ectocervix / vagina by colposcopy or presence of eggs in urine). After stratifying for HIV status, participants with and without urogenital schistosomiasis had similar CD4 cell counts. Furthermore, there was no significant difference in prevalence of urogenital schistosomiasis in HIV positive women with low and high CD4 cell counts. There was no significant difference in the number of eggs excreted in urine when comparing HIV positive and HIV negative women. Our findings indicate that urogenital schistosomiasis do not influence the number of circulating CD4 cells.

Fig 1. Sandy patch on the cervix.

Colposcopic image of the ectocervix showing a grainy sandy patch at 6 o’clock. In addition there are many scattered grains in a sector from 4 o’clock to 7 o’clock. Abnormal blood vessels can also be seen on the mucosa, many near and between the schistosome grains.

Fig 2. Genital lesions, urinary schistosomiasis and CD4.

Boxplots showing CD4 cell counts in HIV negative and positive women with different findings of urogenital schistosomiasis. The whiskers represent the 10th and 90th percentiles. The mean CD4 cell counts showed no significant differences between any of the groups.

Fig 3. Urogenital schistosomiasis and CD4 in HIV positive.

HIV positive women were grouped by CD4 cell count (< 350, 350–500 and > 500 x 10⁶ cells / L). Mean prevalence of findings related to urogenital schistosomiasis was compared across the groups using analysis of variance (ANOVA). The resulting p-value is indicated above each group. Error bars represent 95% confidence intervals. No significant difference was found for any variable across the CD4 groups.

Fig 4. Egg excretion and CD4.

Scatterplot showing CD4 cell counts and urine schistosome egg intensity in HIV negative and positive women. Only women excreting schistosome eggs (n = 156) were included. Regression lines were fitted for each of the groups. No linear associations were found.