Spatial cluster analysis of human cases of Crimean Congo hemorrhagic fever reported in Pakistan

Infect Dis Poverty. 2015 Mar 2;4:9. doi: 10.1186/2049-9957-4-9. eCollection 2015.


Background: Crimean Congo hemorrhagic fever (CCHF) is a tick-borne viral zoonotic disease that has been reported in almost all geographic regions in Pakistan. The aim of this study was to identify spatial clusters of human cases of CCHF reported in country.

Methods: Kulldorff's spatial scan statisitc, Anselin's Local Moran's I and Getis Ord Gi* tests were applied on data (i.e. number of laboratory confirmed cases reported from each district during year 2013).

Findings: The analyses revealed a large multi-district cluster of high CCHF incidence in the uplands of Balochistan province near it border with Afghanistan. The cluster comprised the following districts: Qilla Abdullah; Qilla Saifullah; Loralai, Quetta, Sibi, Chagai, and Mastung. Another cluster was detected in Punjab and included Rawalpindi district and a part of Islamabad.

Conclusion: We provide empirical evidence of spatial clustering of human CCHF cases in the country. The districts in the clusters should be given priority in surveillance, control programs, and further research.

Keywords: Adjusted cumulative incidence; Clusters; Crimean Congo hemorrhagic fever; Pakistan; Spatial autocorrelation.