Soil-Transmitted Helminth Contamination Around Sanitation Facilities in Ile-Ife, Nigeria: The Role of Latrine Type, Soil Characteristic, and Community Knowledge

Why It Matters

The pervasive environmental contamination underscores the limited impact of latrine upgrades alone, highlighting the need for integrated sanitation and behavior‑change programs to curb STH transmission in low‑resource settings.

Key Takeaways

• 78.5% of soils near latrines contaminated with helminth eggs.
• Ascaris lumbricoides detected in 64.2% of contaminated samples.
• Pit latrines showed highest mean egg count; not statistically significant.
• Sandy soils had significantly higher egg concentrations than other soils.
• Community knowledge did not reduce soil contamination levels.

Pulse Analysis

Soil‑transmitted helminths (STH) such as Ascaris lumbricoides, hookworm and Trichuris trichiura remain a leading cause of morbidity in low‑income regions, affecting an estimated 1.5 billion people worldwide. The parasites complete their lifecycle in the environment, making inadequate sanitation a critical driver of transmission. In sub‑Saharan Africa, rapid urbanisation has outpaced the provision of safe latrines, leaving many households reliant on pit or pour‑flush facilities that often fail to contain fecal waste. Understanding how these sanitation structures interact with local soil characteristics is essential for designing effective control strategies.

The Ile‑Ife cross‑sectional survey examined 200 households across four wards, collecting soil within a 100‑metre radius of each toilet. Researchers detected helminth eggs in 78.5 % of samples, with Ascaris present in 64.2 % and hookworm in 20.8 %. Pit latrines recorded the highest average egg density (16.6 eggs/g), while pour‑flush units showed a lower mean (12.8 eggs/g), though the difference lacked statistical significance. By contrast, sandy soils harboured a markedly higher egg load (20.8 eggs/g) than loamy or clayey substrates, confirming soil texture as a key environmental factor.

The findings suggest that upgrading latrine technology alone will not eradicate STH contamination without complementary measures. Despite 90 % of respondents recognizing intestinal parasites, gaps in transmission knowledge persisted and did not translate into cleaner soils, indicating that health‑education campaigns must be more targeted. Policymakers should prioritize integrated interventions that combine improved sanitation infrastructure, soil‑specific mitigation (e.g., covering sandy areas), and behavior‑change programs. Continued surveillance and longitudinal studies will be vital to assess the impact of such multifaceted approaches on reducing the public‑health burden of helminthiasis.