Cysticercosis in Laos: Prevalence, risk factors and predictive mapping

Neurocysticercosis due to Taenia solium is the leading cause of preventable epilepsy in low and middle-income countries. This study describes the first national cysticercosis serosurvey in the Mekong region and the first national predicted prevalence map in Asia.

Two thousand two hundred and sixty-two individuals from 149 random villages across Laos provided serum samples that were tested for cysticercosis using the B158/B60 antigen ELISA. Participants compelted individual questionnaires on risk factors for cysticercosis. Logistic regression with random spatial effects was used to determine significant risk factors. A second geostatistical model using readily available national datasets at the village level produced predicted prevalence maps across the country.

The overall study prevalence was 5.31% (95% CI: 4.44 - 6.29%), with cases detected throughout the country. Prevalence varied significantly between villages with a minimum of 0.00% (95% CI: 0.00 - 5.78%) in some villages and maximum of 43.75% (95% CI: 22.16 - 67.39%) in others, supporting the evidence for cysticercosis hotspots. Sex, wealth index and region were all significant risk factors based on individual responses, whilst distance to the nearest city and poverty were the only significant factors in the national predictive model.

Cysticercosis was found throughout Laos, challenging the previous belief that it was primarily a disease of northern Laos. The significant association with wealth and poverty in both models highlights the need for socioeconomic considerations in disease control. Many of the high predicted prevalence areas exist along the borders with Cambodia, Thailand and Vietnam suggesting that cross-border or regional approaches may be beneficial.