Global Positioning System: a new tool for measurement of animal bites in a rural area near Bangalore,South India

Introduction

Accurate estimates of morbidity and mortality of animal bite and rabies (human and animal) cases have always been difficult to obtain in developing countries like India. Most of the estimates available are collected passively, based on epidemic diseases hospital data; special surveys are exceptions. ¹ Historically animal bite cases have never been mapped either at a national or local level. Global Positioning System (GPS) technology is one tool available which can revolutionise the measurement of morbidity and mortality of animal bite cases. GPS is a satellite-based navigation system that sends and receives radio signals, and by three-point trigonometry localises a specific site. ² There are no published studies using GPS for measurement of morbidity and mortality of animal bites cases. With this in mind, the present study was conducted with the primary objective of spatial mapping animal bite cases using GPS technology and a secondary objective of finding out the incidence of animal bites.

Methods

This exploratory study was conducted in villages coming under three public health centres (PHCs) near Bangalore between September and December 2012. A hand-held GPS (Garmin GPS72H) receiver was used to plot the coordinates of the household of every animal bite case reported in the area.

For assessing the incidence of animal bites, a sample of the population was surveyed, approximately 10,860, based on appropriate sample size calculation. The population was surveyed through multi-stage sampling and the probability proportion to size (PPS) technique.

Results

The GPS receiver was used as a new tool to measure animal bite cases. North and east coordinates observed in the GPS receiver were recorded. These coordinates were then plotted on Google Earth and a spatial map of animal bite cases was constructed (Figure 1). The Google Earth aerial view not only identified the household with animal bites but also gave information on the villages which required action, their topography, distance and location from the PHCs. OPEN IN VIEWER

The route (waypoints) to the households of animal bite cases from the PHC was saved in the GPS receiver. This feature aided in easy identification of households with animal bite cases.

A total of 127 animal bite cases were reported during the study period accounting for an annual incidence of animal bite cases of 1.17% (11.7 per 1000 population per year). The major biting animal was the dog. Category III exposure wounds were observed predominantly but the animal vaccination status was not known (Table 1). All cases had a bite from a suspected rabid animal. ³ The most common reasons for cases to approach a healthcare facility for treatment were self-awareness as a matter of regular place of visit for health related problems (73.1%), television media (11.8%), motivation by neighbours (10.8%) and healthcare providers (4.3%).

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Table 1.

Details of animal bite cases (n = 127).

Profile	Total
Socio-demography
Age (years)
<15	39 (30.7)
15–60	80 (62.9)
>60	8 (6.3)
Male	80 (62.9)
Hindu	114 (89.8)
Labourers/farmers	53 (41.7)
Biting animal
Dog	125 (98.4)
Stray dog	68 (53.5)
Fully vaccinated dog	18 (14.2)
Wound wash with water and soap/antiseptic*	71 (71.7)
Site of wounds †
Lower limbs	96 (74.4)
Category of exposure
Category II	41 (32.3)
Category III	86 (67.7)
Anti-rabies vaccination (ARV) – received ‡	93 (73.2)
Doses of ARV received (n)
3–5	48 (51.6)
Don’t know	2 (2.2)
Site of vaccination †
Arm/Anterolateral thigh	58 (58.1)
Gluteal region	27 (27.6)
Don’t know	13 (13.3)
Route of vaccination (n = 93)
Intramuscular	82 (88.2)
Intradermal	2 (2.1)
Don’t know	9 (9.7)
Rabies immunoglobulin (RIG) – received	6 (6.9)

Discussion

In the present study, GPS technology was able to pinpoint the exact location of the households of animal bite cases. All GPS information is available visually and can be stored permanently. The majority of local government PHCs have already been provided with a computer and Internet facility. Most PHCs in India are required to report weekly data of various diseases online. Healthcare workers can use GPS technology to document and map the problem of animal bites and rabies cases on a real-time basis (weekly/ monthly/yearly). This will be useful in accurate documentation of morbidity and mortality data and visual feedback after interventions.

Today, there are a range of different geographical distributions or baseline ‘risk’ maps available, ⁴ which have been derived for a variety of purposes, by a wide community of public health cartographers using a diverse toolbox of mapping methods.^5,6

The data obtained by spatial mapping using GPS technology were achieved at minimal cost and after a minimal learning curve. GPS technology and Google Earth can be used together at an affordable cost which will be a huge boon to countries like India. Expensive sophisticated software like Geographical Information System (GIS) and other technologies available are not required. Google Earth software is available for free and can be downloaded by anyone anywhere.

There are no global estimates of dog-bite incidence; however studies suggest that dog-bites account for tens of millions of injuries annually. ⁷ The data on animal bites are scanty in India. ⁸ The estimated Indian animal bite incidence rate was 1.7%. ¹ The present study showed that animal bites continue to be a problem in the rural areas. Further studies involving larger geographical areas using GPS technology are needed in order to obtain a more precise estimate of the burden of animal bites.