Researchers have studied the socio-economic drivers of E. coli and Cryptosporidium infection in Ireland.

While incidence cannot be predicted solely based upon metrics such as education and employment, both infections are partly driven by such factors, said scientists.

STEC in rural areas has been associated with direct farm animal contact and contaminated drinking water, while food products have been reported as a significant driver in urban areas.

The Republic of Ireland has the highest rates of Shiga-toxin producing E. coli (STEC) and cryptosporidiosis in Europe. Incidence of both infections are higher in rural areas.

Findings may improve risk communication and surveillance to protect public health across socio-demographic profiles, according to the study published in the journal Epidemiology and Infection.

Young children mostly affected
Confirmed STEC cases between January 2013 and December 2017 were included for analyzes, as were data for primary and secondary cases of cryptosporidiosis from January 2008 to December 2017. Overall, 2,757 cases of STEC were geocoded to one of 12,246 categorically urban small areas and 6,242 rural small areas.

A significantly higher proportion of cases occurred among children younger than 5 years of age and people older than 65. Infection was relatively even among males and females.

In total, 4,509 confirmed cases of cryptosporidiosis were geocoded to 3,412 small areas, of which 2,027 small areas were rural and 1,385 were urban. Just under 60 percent of infections were among children under 5 years of age, with not much difference with respect to gender.

Young children may be at increased risk because of immature immune systems, frequent contact with other youngsters, lower standards of hygiene and susceptibility to infection.

Higher total population number was associated with both organisms in urban and rural areas and across both time periods. Higher local populations and density are often linked to economic deprivation, particularly in urban areas.

This highlights population density with person-to-person contact and vulnerable sub-populations as important transmission drivers, found the study.

Lower mean household density was associated with incidence of both infections in urban areas. Researchers said this was unexpected based on previous studies which report household size and structural profile as a proxy for secondary transmission. Domestic transmission and overcrowding are important risk factors for cryptosporidiosis. A lower proportion of local authority housing was associated with STEC presence in urban areas.

Education and employment results
Lower rates of third-level education, unemployment and household density were associated with infections in urban areas only.

Incidence of STEC in rural areas was significantly associated with lower levels of third-level education, likely reflecting the prevalence of agricultural based employment in rural Ireland, which is typically passed down through generations. Lower levels of third-level education were associated with cryptosporidiosis in rural areas.

Significant associations were identified between the presence of both infections and lower rates of male and female unemployment in rural areas.

Lower levels of poverty have been associated with STEC incidence in some countries due to healthcare-seeking behaviors among higher income populations.

Lower proportions of lone parent households and higher amounts of semi-skilled and unskilled workers were associated with incidence of cryptosporidiosis but not STEC.

Higher rates of female and male unemployment were associated with cryptosporidiosis in urban areas, suggesting the relationship between affluence and cryptosporidiosis is not nationally uniform.

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