Abstracts

Rationale:
Subarachnoid neurocysticercosis (SANCC), a highly morbid form of infection with Taenia solium, is most commonly brought to medical attention at a late stage when treatment options are limited. In later stages of disease, individuals often develop epilepsy as well as hydrocephalus. This study attempts to validate urine based screening for asymptomatic SANCC in an effort to find these individuals early and potentially offer disease modifying interventions prior to the onset of symptoms as SANCC has not been detected in prior population-based neuroimaging studies in endemic areas.
Method:
Residents of the northern-most state of Peru (n=8131), Tumbes, were screened using a urine based assay for SANCC. An existing urine based antigen screen for cysticercosis was repurposed using a higher urine antigen ratio threshold, set in an earlier pilot study, to identify potential cases. Individuals who met the urine ratio threshold were offered an MRI Brain to evaluate for SANCC.
Results:
Of the 8131 individual screened, 79 met the determined urine ratio threshold and were offered MRI. MRI was obtained on 63 individuals, and 15 showed evidence of SANCC. Another 7 had non-subarachnoid forms of viable neurocysticercosis. When looking specifically at regions with known high infection rate, the minimum prevalence was as high as 6.6 per 1000 persons (95% CI: 4.4-9.4). In these same regions, the positive predictive value (PPV) of the urine screen was 27.5% for SANCC and 41.2% for all neurocysticercosis.
Conclusion:
This favorable PPV of urine screening is promising and suggests that screening for SANCC would be high yield for these health systems. The higher than expected minimum prevalence of SANCC further supports the importance of identifying these cases prior to symptom onset and exploring options for early intervention to prevent the well documented high rates of morbidity and mortality associated with this infection.
Funding:
:US National Institute of Neurological Disorders and Stroke (R01NS103623)