Cyst morphology and serological variation in cystic echinococcosis patients from Turkana, Kenya

Cystic echinococcosis (CE) is parasitic disease caused by cestode E. granulosus. Turkana in Northern Kenya carries one of the highest CE burdens in the world. Between 1983 and 2015 a control programme implemented there by African Medical Research Foundation (AMREF) using ultrasound screening for diagnosis evaluated CE prevalence. Several treatment options were available in the programme for those affected. This programme generated a vast amount of raw data as well as serum samples from infected patients was analysed in the first part of this project to assess the efficacy of treatments in Turkana. Data analysis showed that 7.9 % of untreated cases achieved spontaneous cure and 34% improved without intervention. Chemotherapy appeared to stabilise the cysts rather than cure and increasing dose to two was ineffective in inactive cysts. Surgical outcome was improved with chemotherapy from 85% to 91% cure. The project also sought to undertake a detailed analysis of serum antibody responses of individual patients and correlate them to gross ultrasound pathologies. Five recombinant antigens identified from literature to have different properties were purified and optimised. These were Echinococcus granulosus antigen B (EgAgB), Echinococcus granulosus elongation factor 1 beta/delta (EgEF-1β/δ), Echinococcus granulosus fatty acid binding protein 1 (EgFABP1), Echinococcus granulosus heat shock protein 70 (EgHSP70) and Echinococcus granulosus thioredoxin peroxidase (EgTPx). Crude hydatid cysts fluid was also used for comparison. The optimised antigens were then assessed for differential immunoreactive properties towards specific total IgG and sub-classes 1 and 4 serum antibodies. Significant differences in expression of IgG1 and IgG4 was found in response to some antigens. In simple cysts (CE1), IgG4 was highly expressed in comparison to IgG1, in response to HSP70 and EgEF-1β/δ while in cases where the characterised by cyst infiltration and calcification (CE4) cysts, IgG1 was the prominent antibody in response to HSP70, EgEF-1β/δ and HCF. The best diagnostic tool was found to be expression of IgG1 in response to TPx which showed sensitivity of 95%. In follow-up, responses of total IgG towards AgB was found to be useful. It increased in all recurring cases, decreased in all improved cases and remained relatively constant in unchanging cysts. Use of circulating antigens rather than antibodies in diagnosis showed better results in active cyst. In patients with CE1 cysts, antigen levels were seropositive for 91.1 % (31/34), in CE2 cases 81% (34/42) of the patients, in CE3 cases 42% (9/21) and in CE4 cysts and 59 % (16/27). Overall hydatid cyst antigens were detected in 72.6 % (90) of the cases