Martin Boudou (Ireland)

Dublin 7 Environmental Health Institute

Presenter of 1 Presentation

DEVELOPING A “SPACE-TIME RECURRENCE INDEX” FOR INFECTION IN THE REPUBLIC OF IRELAND, 2008-2017 – A SIMPLE TOOL FOR INDENTIFYING SPATIOTEMPORAL PATTERNS OF PAEDIATRIC CRYPTOSPORISIOSIS (ID 111)

Lecture Time
10:30 - 10:37
Room
Hall 01

Abstract

Background

Cryptosporidiosis is an acute gastro-intestinal disease leading to acute dehydration and death in severe cases, particularly among immuno-compromised individuals, including children ≤5 years. Ireland reports the highest Crude Incidence Rates in the EU, with approximately 60% of annual cases attributed to children, however, the spatiotemporal patterns of domestically acquired (sporadic and outbreak-related) cases have not been fully elucidated.

Methods

SaTScan v9.6 was used to undertake space-time scanning of confirmed cases of paediatric cryptosporidiosis notified in Ireland from January 1st 2008 to December 31st 2017 (2,672 cases). Cases were geo-coded to one of ~19,000 Census Small Areas (SAs), with discrete Poisson modelling employed for scanning at high spatial resolution. All significant space-time clusters (p < 0.05) were mapped, with binary cluster location summed at SA scale. Final maps provide a “cluster recurrence” index (0 to 10) for the study period.

Results

Three high recurrence “hotspots” were identified, including a large area north-east of Galway City, and two areas south-west and south-east of Limerick City (Figure 1). Identified clusters largely mirrored annual peaks of infection (late spring/early summer). Notably, no space-time clusters were found in major urban conurbations over the study period (i.e., “cold-spots”).

paediatriccrypto.png

Conclusions

The space-time recurrence index offers a simple approach to identify spatiotemporal patterns of infection, with presented analyses detecting three spatial clusters omitted from routine surveillance. The spatiotemporal epidemiology of cryptosporidiosis reflects the diverse population and geography of the country, with a markedly higher rate of occurrence in rural areas, likely due to the ubiquity of Cryptosporidium spp. sources (e.g., cattle) and pathways (e.g., karstic limestone bedrocks). The elevated burden among children ≤5-years is likely related to immunological status and specific routes of exposure, warranting further study.

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