Spatio-temporal epidemiology of dog bite injuries at Kakamega Provincial Hospital, Kenya

Spatial epidemiology is the study of spatial variation in disease risk or incidence. Several ecological processes can result in strong spatial patterns of such risk or incidence: for example, pathogen dispersal might be highly localized, vectors or reservoirs for pathogens might be spatially restricted, or susceptible hosts might be clumped.(Ostefield et al 2005).

In Kakamega District of Western Kenya We Assesed The Reporting patterns of Vertebrate bites in the Provinicial Referral General Hospital.

Spatio-temporal epidemiology of dog bite injuries at Kakamega Provincial Hospital, Kenya

Kelly A Nelima1, 6, Mark OO Nanyingi 2, 3§, Gideon M. Kikuvi4, Willis Akhwale5, Jared Omolo6
1Ministry of Livestock and Development, Provincial Veterinary Office, PO BOX 871, Kakamega, Kenya
2 Ministry of Livestock and Development, District Veterinary Office, PO BOX 60 -50135, Khwisero, Kenya,
3 Kenya Scientific Analysts, P.O. Box 531-00202, Kenyatta National Hospital, Nairobi, Kenya,
4Jomo Kenyatta University of Agriculture and Technology, Box 3249-00200, Nairobi, Kenya
5 Ministry of Public Health and Sanitation, PO Box 30016- 00100 Nairobi, Kenya
6 Field Epidemiology and Laboratory Training Program, US centers for Disease Control, PO Box Nairobi, Kenya

Abstract

Background
Endemic canine rabies is a reemerging neglected zoonosis often underestimated in Kenya but remains a public health and economic burden to the rural poor. Understanding the transmission dynamics and distribution of dog bites over specified time period can assist in assessment of risk factors, design of interventions to exposure and the estimation of rabies burden.

Methods
Retrospective and cross-sectional analysis of surveillance data of reported dog bite incidents from Kakamega Provincial General Hospital from 2006 to 2009 was performed to estimate the prevalence of dog bites. Univariate and Multivariate analysis were performed to assess the risk factors and prevalence of dog bites. The temporal distribution and spatial patterns of bites was mapped and analysed to estimate population at risk to rabies.

Results
There were 148 dog bite incidents with children below 10years being more involved (33.8%).Most bites occurred on the lower extremities 124/148 (83.8. 1.0% of bites resulted in rabies and death after post exposure treatment and were located more than 45km away from the PGH. Spatial-temporal clustering of dog bites showed irregular pattern of spread with declining incidence rates from the periurban center. On visual inspection, the highest (30%, 95% CI 14-52% N = 45) densities of dog bites were in areas around the central place of the study area, bites clustered in not more than 15km radius from the hospital. The second cluster centered around Lubao dog market 7.4 %( 95% CI, 5-12%, N = 11). 12% of the bites were along roads and rivers while 5% occurred in and around forests. The retrospective analysis revealed a temporal increase in prevalence 114 % (P<0.05) with high peaks in March and August with a mean monthly bite incidence of 22.44%. 2008 had the highest mean monthly incidence of 30%.

Conclusions
Spatiotemporally dynamic approaches and epidemiological models may predict emergence or spread of diseases to new geographic regions and could be effective in spatially targeting interventions. Descriptive spatial epidemiology of bites can assist in accurate measure of rabies burden where underreporting, inequity in vaccine provision and improper policies of disease mitigation exist.

Key words: Spatial epidemiology; Dog bites, Rabies.

© 2010 Khwisero District Veterinary Office

§Corresponding author and presenter: mnanyingi@gmail.com, +254721117845.