Hands and water as vectors of diarrheal pathogens in Bagamoyo, Tanzania

Area of Science:

• Environmental microbiology
• Public health
• Molecular epidemiology

Background:

• Diarrheal disease is a primary cause of mortality in children under five globally, particularly in sub-Saharan Africa.
• Understanding pathogen transmission routes (water, hands) is crucial for effective intervention.
• Existing knowledge on the relative importance of different exposure routes for enteric pathogens is limited.

Purpose of the Study:

• To investigate the relative importance of different exposure routes for enteric bacteria and viruses in Tanzanian households.
• To identify key transmission pathways for diarrheal pathogens in a high-burden region.

Main Methods:

• Molecular detection of enteric bacteria (pathogenic Escherichia coli virulence genes) and viruses (rotavirus, enterovirus, adenovirus).
• Sampling of hand rinses, stored water, and source waters in Bagamoyo, Tanzania.
• Analysis of pathogen occurrence and correlation with environmental and sanitation factors.

Main Results:

• Viruses were most frequently detected on hands, indicating hands as significant vectors for viral transmission.
• Escherichia coli virulence genes occurred equally across hands and water samples, suggesting dual transmission routes for bacterial pathogens.
• Fecal indicators and turbidity predicted bacterial genes, while turbidity and human-specific Bacteroidales predicted viral genes.
• Pathogen occurrence was linked to water source quality and sanitation conditions.

Conclusions:

• Hands play a critical role in the transmission of viral diarrheal pathogens.
• Both water and hand hygiene are essential for controlling bacterial diarrheal diseases.
• Interventions promoting hand-washing and improved water management are vital for reducing childhood diarrheal disease in this region.