Acta Tropica, 55(1993)249-255 249 © 1993 Elsevier Science Publishers B.V. All rights reserved 0001-706X/93/$06.00

ACTROP 00339

Dog-bite injuries at a Bangkok teaching hospital

Kasian Bhanganada a, Henry Wilde b'*, Piyasakol Sakolsataydorn a and Pairoj O o n s o m b a t a

aDivision of Trauma, Departments of Surgery and of Social and Preventive Medicine, Siriraj Hospital of Mahidol University, Bangkok, Thailand, and bQueen Saovabha Memorial Institute of the Thai Red Cross

Society and Department of Medicine, Faculty of Medicine, Chulalongkorn University, 1871 Rama IV Road, Bangkok 10330, Thailand

(Received 2 April 1993; revised version received 13 July 1993; accepted 6 August 1993)

Thailand has a large domestic and stray dog population and Buddhist cultural beliefs encourage feeding and protection of stray animals. Dog bites are common injuries encountered in emergency rooms through- out the country. A prospective study of such bites seen at a teaching hospital in Bangkok revealed that: (1) dog bites represent 5.3% of injuries seen in the emergency room; (2) the majority occur on the street, are inflicated by stray dogs and are interpreted by the victim as unprovoked. Children and teenagers account for 55% of the victims. The lower extremities (54%) and upper extremities (20%) were the most common sites for bites. 9% of patients were bitten on the face or head. In addition to pain, risk of infection (approximately 13%) and the significant cost of caring for these injuries, victims often experienced pro- longed anxiety because of to the generally known risk of rabies in Thailand. Due to the high cost of imported immune globulins and vaccines, rabies exposures are not always managed optimally in Asia.

Key words: Dog-bite injury; Bite injury; Animal bite; Epidemiology; Thailand; Rabies

Introduction

Dog bites are a serious public health problem in developing countries (Thongcharoen et al., 1985, Dalton et al., 1988, Wilde et al., 1991). Thailand also has an endemic canine rabies problem that represents a hazard to natives and visitors to the Kingdom alike. An estimated 150000 individuals receive postexposure rabies vaccination annually, but there are, nevertheless, approximately 200 recorded human rabies death in Thailand every year. Siriraj Hospital is a 2000-bed tertiary care university center. It is located in a densely populated part of Metropolitan Bangkok and serves mostly the low-income population. Animal bite victims are a common occurrence in the trauma unit and we therefore embarked on a study of all dog bites that had presented to Siriraj Hospital. This was done to delineate the magnitude of the problem and to identify circumstances and localities where and when dog attacks are most likely to occur.

Corresponding author. Fax." + 66 2 2540212.

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Material and Methods

This study was carried out prospectively from 1 January to 31 December 1987. All dog-bite victims presenting to the emergency and trauma unit of the hospital during this time were included and this investigation was part of a larger study of the epidemiology of trauma that included rapes, snake bites, assaults and vehicular accidents. The circumstances surrounding the bite incident and extent of injuries were recorded and transcribed on a personal computer using a previously prepared study protocol. All patients were seen by senior medical students and surgical house staff. Wounds were irrigated with normal saline. Grossly contaminated wounds were washed and scrubbed using povidone iodine solution. Dry dressings were applied to small wounds and abrasions. All large wounds were sutured or left open and dressed with saline-soaked gauze. Patients were seen daily for change of dressings until the wounds had healed or were considered ready for secondary suture. Those with clean wounds were not given antibiotics. Patients with large wounds that were grossly contaminated and/or macerated and wounds that were sutured received penicillin, ampicillin or tetracycline. Primary or booster tetanus toxoid was given where appropriate. After primary wound care, patients were referred elsewhere for rabies postexposure vaccination.

Results

A total of 44 213 patients were seen in the trauma unit during this 12 months study period. 2326 (5.3%) of these were dog-bite injuries. 1110 were male and 1216 were female. Fig. 1 demonstrates the age distribution of dog-bite victims. The largest age group at risk were children under 10 years and those between 10 20 years. They, together, made up 55% of all dog-bite victims (Fig. 1). The youngest patient who came with a dog bite was 12 months old and the oldest 77 years.

The majority of dog-bite patients came from within a 3 km radius of Siriraj Hospital. Several attacks by dogs occurred within the compound of Siriraj Hospital. Patients came to the emergency room primarily because of convenience. The bite

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500 . . . .

400

300

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100

0 ~10 11"20 21-30 31-40 41-60 61-00 61-70 )71

Fig. 1. Ages of dog-bite victims. Total, 2326; males, 1110; females 1216.

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incident occurred on a street in 45% of the victims and only 8.5% were bitten at their own home (Table 1). The time when the dog attack occurred was between noon and 6 p.m. in 40.4%, between 6 a.m. to noon in 26.8%, from midnight to 6 a.m. in 13.8% and between 6 p.m. to midnight in 12.5%. The time was not recorded in 6.5% of cases. Unprovoked attacks, while coming near the dog, were common (47.5%). The victim was running when bitten in 10% of these cases. Only 30.8% of dog-bite patients gave convincing histories of having provoked the dog to bite (Table 2). Details of the attack were not available in 11.7% of the cases. Provoking included such activities as stepping on the dog, chasing or beating a dog or interfering in a dog fight. Handling a dog with puppies was also classified as a provoked attack. A small number of victims were bitten while feeding an unknown dog (3.9%). All other activities were considered unprovoked. The majority of dog bites were by stray or so-called community dogs (Table 3). However, this figure may be exaggerated, since dog ownership is often denied when the animal has been involved in an attack. The dog's vaccination status, general health and whether it was rabid or not could not be determined, since the majority were stray animals and were not captured or available for observation or examination.

The nature of wounds is illustrated in Table 4. The lower extremities were the most common sites and they were classified as puncture wounds in 73% of patients. Primary suture was performed in only 3.5% of patients and 17% of these became infected. Table 5 demonstrates the sites of wounds. Follow-up in this group was not complete and some of these patients went to other health facilities when wounds

TABLE 1

Where the dog bite took place

Location Number Percent

Within 3 km radius of Siriraj Hospital 1581 68 Street 234 10.1 Own home 198 8.5 Market 257 11.1 Temple, School, Hospital (*) 236 10.1 Not recorded 355 15.2

(*) 12 bites occurred within the Siriraj Hospital complex.

TABLE 2

Circumstances of attack

Number Percent

A. Unprovoked 1340 57.5 Standing or walking 1104 47.5 Running 236 10.0

B. Provoked 715 30.7 Intervening in dog fight 224 9.6 Stepping on dog 106 4.7 Feeding strange dog 93 3.9 Handling the dog 292 12.6

C. Not recorded 271 11.7

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TABLE 3

Ownership of dogs

Number Percent

Stray 1558 67.0 Own dog 215 9.2 Neighbor's dog 317 13.6 Temple, School or Hospital dog 236 10.3

TABLE 4

Wound characteristics

Number Percent

Puncture wound 1709 73.5 Laceration 426 18.3 Abrasion 127 5.5 Not recorded 64 2.8 Sutured, face 41 1.8 Sutured, trunk 3 0.1 Sutured, perineum 3 0.1 Sutured, leg and foot 31 1.3

TABLE 5

Site of bites (*)

Number Percent

Head and face (**) 208 10.7 Trunk 65 3.1 Arm 204 9.9 Hand and fingers 262 12.7 Buttock and perineum 67 3.2 Leg and foot 1259 61.0 Not recorded 33 1.6

(*) Some victims sustained multiple bites. (**) 70% of these were children.

became infected and for suture removal. We do, however, know from a prospective study at the Queen Saovabha Memorial Institute (Wilde et a1.,1992) that approxi- mately 13% of animal inflicted deep puncture wounds and lacerations become infected and that infection is usually apparent on days 3-7 post injury. It is not known whether any of the patients in this study later developed rabies, since they were sent to other facilities for postexposure vaccination. A total of 5.3% victims reported having experienced previous dog-bite injuries. 2.6% of these had one, 1.1% two, 0.65 three and 1% more than three previous bites.

Cost analysis of wound care for this group of patients seen at Siriraj Hospital revealed the following: The total cost to the hospital (excluding salaries to nurses and house staff) for caring for the 2326 victims was Baht 558 240 (US$ 22329). Virtually all of these patients belonged to the lower socio-economic strata of society

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where the average daily income (minimum legal daily wage) per worker was US$ 3.60-4.00 at the time of the study. Table 6 illustrates details of these costs in Thai Baht (1 US$ = 25 Baht) and in terms of the then minimum Thai daily wage which this cost represented to the average worker. Costs for rabies immune globulin and rabies vaccine have not been included in this calculation and these represent a very significant additional financial burden to patients and the institutions responsible for postexposure rabies vaccination (Wilde, 1991).

Discussion

Buddhist cultural beliefs encourage the feeding of animals and there is often com- munity resistance to rigid dog control measures. Collecting and killing street dogs is particularly offensive to the general public. Estimates of the stray, owned and semi-owned dog population of Thailand range around 10 million; with a man to dog ratio of 5.5:1. Side lanes, schools, public markets and temples in Thailand are noted for harboring many of these stray animals. Efforts to mass vaccinate them have been made at regular intervals, but lack of adequate funding has so far hampered creation of a truly effective ongoing control and vaccination program throughout the country. Efforts to control the large stray dog population within the Siriraj Hospital compound have also failed due to resistance from the public, who often feel that feeding these dogs gives them spiritual merit which may benefit their hospitalized family members. It has, furthermore, been shown that vaccination of dogs in Thailand has not resulted in complete protection from rabies infection. Between 3 and 9% of dogs found rabid by Ministry of Health and the Queen Saovabha Memorial Institute's diagnostic laboratories have a vaccine history (Tepsumethanon et al, 1991). Furthermore, it has been shown that not all dogs vaccinated with the vaccine manufacturer's recommended one-dose primary injection maintain protective levels of antibodies (defined by WHO as over 0.5 IU/ml) after 2 months (Tepsumethanon et al., 1991, Sage et al., 1993). An unpublished survey by P. Phanuphak and S. Chutivongse of 20 000 Thai school children revealed that 25% had experienced dog bites by the age of 15 years. Wounds inflicted by dogs can be severe and result in disfiguring injuries, infection, pyomyositis, osteomyelitis and permanent disability. Caring for such wounds is expensive. Virtually every Thai

TABLE 6

Cost of wound care

Cost, Baht Days at min imum wage

Cleaning of wound Dressing of wound Antibiotics when indicated Tetanus toxoid Suture material when indicated Local anesthetics when needed Average cost of sutured wound care Average number days not working

16 0.17 55 0.80 50 0.55 30 0.33 38 0.42 45 0.49

320 3.48 2.2

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knows about rabies and has had a family member, neighbor or friend who has died of this disease. The fact that vaccination with still commonly used brain tissue derived rabies vaccines can result in serious adverse reactions is also generally known (Thongcharoen et al, 1985). The public is also aware that such vaccination may not provide 100% protection for all and that human rabies deaths have been reported in spite of vaccination (Wilde et al., 1989). Every dog bite is therefore associated with economic loss and anxiety that may persist for several months or even years after the wound has completely healed. An added concern is that many dog-bite victims in Thailand do not receive postexposure care that fulfills management criteria recommended by the World Health Organization (WHO, 1992) and the Rabies Committee of the Thai Red Cross (Thai Red Cross,1993).

Our data are in agreement with Dalton's findings from Arctic Alaska (1988), where children under 10 years are the most common dog-bite victims (30%). They also are the most likely to be bitten on the face and head. Extremity bites (Dalton 73%, Siriraj 74%) are the most common (Table 5). The youngest victim in this series was 1 year old and this is in keeping with the experience at the Queen Saovabha Memorial Institute, the major rabies post-exposure treatment center for Central Thailand, which has encountered only a few instances of infant attacks by dogs.

This study defined and categorized dog bites as 'provoked' and 'unprovoked' (Table 2). We have often wondered whether this is a meaningful distinction in terms of assessment of rabies risk in a canine rabies endemic region and whether rabies postexposure management decisions should be influenced by it. A recent study by Siwasontiwat et al. (1992) revealed little correlation between a dog biting 'provoked' or 'unprovoked' with the final laboratory diagnosis. Siwasontiwat's criteria for defining 'provoked' and 'unprovoked' were similar to those used in this study. If the majority of 'provoked' bite victims in this study had also been referred for postexposure rabies vaccination, as they certainly would be today, an even greater economic loss would have ensued. Foreign tourists are not spared contact with dogs. The Queen Saovabha Memorial Institute at Bangkok treats approximately 100 foreigners (0.6% of total victims seen) for animal bites yearly. A much larger but unknown number of foreigners are treated at private hospitals for dog-bite injuries. We know of two foreigners who died of rabies in Thailand during the past 3 years: an American priest bitten in Bangladesh and evacuated to Bangkok, and a German who was bitten and died at a Thai beach resort. Neither had received pre- or postexposure rabies vaccination.

We conclude that dog-bite injuries represent a major public health hazard in Thailand. Unprovoked attacks in public places are the most common circumstances. Children, teenagers and persons walking along streets are at greatest risk. Dog bites also represent a significant economic burden for patients and health care providers (Table 6). Reducing the number of stray and semi-owned dogs and vaccinating them should remain an urgent and continuing goal. The fact that dog control can be accomplished in South East Asia has been demonstrated by neighboring Peninsular Malaysia and Singapore, where canine rabies has been virtually eliminated (Soon, 1988).

References

Dalton, L.M., Hanns, C.T., Nelson, E.A. and Hughes, T. (1988) Public health aspects of stray dogs in Barrow, Alaska. Arctic Med Res. 47, (S1) 83-89.

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Sage, G., Khawplod, P., Wilde, H., Lobaugh, C., Hemachudha, T., Tepsumethanon, W. and Lumlertdaecha, B. (1993) Immune response to rabies vaccine in Alaskan dogs (Failure to achieve a consistently protective antibody response). Trans. R. Soc. Trop. Med. Hyg., in press.

Siwasothiwat, D., Lumlertdacha, B., Polsuwan, C., Hemachudha, T. and Wilde H. (1992) Rabies: is provocation of the biting dog relevant to risk assessment? Trans. R. Soc. Trop. Med. Hyg. 86, 443.

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Wilde, H., Bhanganada,K., Chutivongse, S., Siakasem, A., Boonchai, W. and Supich,C. (1992) Is injection of contaminated animal bite wounds with rabies immune globulin a safe practice? Trans. R. Soc. Trop. Med. Hyg. 86, 86 88.

WHO Expert Committee on rabies (1992) WHO Technical Report Series 824, 8th Report. World Health Organization, Geneva.