Table 1: Factors that affect prevalence and adequate surveillance of cryptosporidiosis.

Epidemiological indexes
Population age
Gender
Individual immunological status
Geographical distribution and ethnic group

Human activities
Hygienic and diet practices
Rural and urban settings
Human waste contamination
Livestock pollution
Water treatment systems; food preparation styles and procedures
Travels, immigration

Environmental and social affecting factors
Animal pollution
Famine, malnutrition, dehydration
Geography, international adoptions
Calamities (typhoons, local wars, floods, etc)
Climate variation, pollution, deforestation and seasonal rains

Under-ascertainment factors in surveillance
Improper sampling of contaminated water systems and food
Difficulty to identify the likely source of infection
Misidentification of outbreak sources
Multiple protozoan coinfections

Under-ascertainment factors in clinics and diagnosis
Poor or diversified symptom presentations and low clinician’s sensitivity to consider protozoa as agents of gastrointestinal infections
Limited inclusion of protozoan searching in operational diagnostic workflows
Self-limiting infection course in immunocompetent adults and children
Low inclusion of advanced molecular tools for routine diagnosis