Collider Bias Assessment in Colombian Indigenous Wiwa and Kogui Populations with Chronic Gastroenteric Disorder of Likely Infectious Etiology Suggests Complex Microbial Interactions Rather Than Clear Assignments of Etiological Relevance.

Multiple microbial detections in stool samples of indigenous individuals suffering from chronic gastroenteric disorder of a likely infectious origin, characterized by recurring diarrhea of variable intensity, in the rural north-east of Colombia are common findings, making the assignment of etiological relevance to individual pathogens challenging. In a population of 773 indigenous people from either the tribe Wiwa or Kogui, collider bias analysis was conducted comprising 32 assessed microorganisms including 10 bacteria ( spp., spp., enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), spp., Shiga toxin-producing (STEC), spp./enteroinvasive (EIEC), and spp.), 11 protozoa ( spp., spp., spp., , , /// complex, , , , and ), 8 helminths ( spp., , spp., , spp., spp., spp. and spp.), microsporidia ( spp.) and fungal elements (microscopically observed conidia and pseudoconidia). The main results indicated that negative associations potentially pointing towards collider bias were infrequent events (n = 14), while positive associations indicating increased likelihood of co-occurrence of microorganisms quantitatively dominated (n = 88). Microorganisms showing the most frequent negative associations were EPEC (n = 6) and spp. (n = 3), while positive associations were most common for spp. (n = 16), (n = 15), spp./EIEC (n = 12), spp. (n = 11) and spp. (n = 10). Of note, positive associations quantitively dominated for spp. In conclusion, collider bias assessment did not allow clear-cut assignment of etiological relevance for detected enteric microorganisms within the assessed Colombian indigenous population. Instead, the results suggested complex microbial interactions with potential summative effects. Future studies applying alternative biostatistical approaches should be considered to further delineate respective interactions.

PMID: 38792799