Epidemiology of Injuries Caused by Mammals Treated in Emergency Departments in Marseille, France

A total of 304 patients with mammal-related injuries were included over the 2-year survey period (1.5% of total admissions) at the emergency departments of a large city in southern France. Admissions peaked during the summer months. Dogs accounted for 75.3% and cats for 16.8% of cases. Dog injuries were significantly more common in younger individuals. Overall, signs of infection were observed in 17.9% of cases and were more likely to occur in patients injured by cats and in patients injured more than 1 day before consulting. The majority of patients received an antibiotic prophylaxis, independent to the delay between injury and consultation. Only 1 out of 10 injured patients who consulted an emergency department were seen at the rabies treatment center. Emergency department surveillance data offers an effective and efficient method for conducting animal bite surveillance to monitor trends and characterize animal bite victims.

Animal bites are a public-health concern, notably in Europe where an estimated 196 million pets are living in close association with humans, with the most frequent complications being infections.¹ Studies on animal bites in Marseille, France have only previously been conducted in the setting of the rabies treatment center.^2,3 The aim of this survey was to describe the epidemiology of animal bites in the larger setting of emergency departments (EDs) in the city.

Study population. Patients admitted to 3 EDs of the Assistance Publique–Hôpitaux de Marseille Marseille Public University Hospital System (APHM) between  January 1, 2011 and December 31, 2012 in relation to a mammal bite, were included. The authors used retrospective data from archived master files of EDs surveillance data collected by the department of statistics of the APHM to identify records. Medical records were scanned for demographics, bite circumstances, clinic, initial treatment, and outcome.

Statistical analysis. Pearson’s Chi-square test was applied to analyze the categorical variables. Statistical analyses were performed using SPSS software package version 17 (SPSS Inc., Chicago, IL), with P values of 0.05 or less considered significant.

Of 333 eligible patients (1.5% of total admissions), 29 cases were not included because the medical files were unavailable and the final analysis was conducted for 304 patients (Table 1 and continued). The majority of patients resided in Marseille (n = 237, 78.0%), with others residing in neighboring municipalities (n = 56, 18.4%) or in other French regions (n = 11, 3.6%). The mean age of patients was 35.8 years (SD, 20.9; age range, 1-89) with a male-to-female sex ratio of 1.2. Infants < 15 years accounted for 19.7% of cases. Most of the injuries were caused by dogs (75.3%) followed by cats (16.8%). Infants were more likely than adults to be bitten by dogs (98.2% vs 77.7%) than by cats (1.8% vs. 22.3%), P = 0.001. The data showed 54.1% of patients were injured by their own animal or by an animal owned by friends or relatives. The mean time between injury and consultation was 1 day (range 0-61 days). An increase in the number of dog-related injury cases was observed during summer months (Figure 1).

Most injuries were in upper and lower limbs and were transdermal bites. Signs of infection were observed in 17.9% of cases. Patients injured by cats were more likely to present with signs of infection compared to those injured by dogs (50.0% vs. 12.1%); P < 10_-3). Signs of infection were more likely to occur in patients injured more than 1 day before consulting compared to others (37.9% vs. 15.4%; P = 0.003). The majority of patients were outpatients (98.0%). Overall, 74.0% of patients received an antibiotic, with amoxicillin-clavulanic acid being the most frequently used. There was a slightly higher proportion of antibiotic use among those with signs of infection (91.1%), compared to those without signs of infection (87.4%). The proportion among the latter was not significantly different between those seen 1 day or less prior to injury (88.0%) and those seen more than 1 day following injury (76.9%). The mean duration of treatment was 7.4 days (range: 2-14 days) and did not significantly differ between patients with or without signs of infection. Only 31.0% of patients who were referred to the rabies treatment center actually presented to the center. No cases of rabies were observed during the study period.

A major finding of this survey is that only 1 out of 10 injured patients who consulted an ED were seen at the rabies treatment center, either because they were not referred or did not consult despite being referred. This confirms that the incidence rate of animal bites when calculated based on the rabies treatment center data is dramatically underestimated.⁴ Emergency department surveillance data offers an effective and efficient method for conducting animal bite surveillance to monitor trends and characterize animal bite victims.⁵ The authors’ description of bite victims mirrors findings from other recent studies conducted in EDs in Italy and in the US; regarding the predominance of dogs among biting animals, the higher likelihood of young patients being bitten, the seasonal pattern of bites, and the high infection rates following cat bites.^1,5,6 The last case of autochthonous human rabies case in continental France was reported in 1924. The few human cases diagnosed in mainland France since then were injured abroad.⁷ France has been declared officially rabies free in non-flying mammals according to the World Organization for Animal Health (OIE) criteria in 2001 but lost its rabies-free status in February 2008, following 2 cases of secondary and tertiary transmission on the national territory indirectly related to an imported rabies case from Morocco, in late 2007. The rabies-free status was recovered only in February 2010.⁷ In 2013, a total of 8,458 patients with an animal-related injury presented to a French rabies treatment center, of whom 51.5% received rabies postexposure prophylaxis (RPEP). Because of a residual risk of importation of rabid dogs in France, most patients injured by animals that cannot be kept under surveillance still receive RPEP, although there is no consensus at the moment among French experts.⁷

Much information was missing in the medical records included in this survey, notably regarding the relationship to the animal and the circumstances of the bites. The ideal record should comprise demographics of the victim, type of animal, and its relationship with the victim, date and place of exposure, and activity of the victim at the time of injury, as well as clinical and therapeutic information.

Although the high risk of infection may suggest the administration of antibiotic prophylaxis, its systematic use is controversial. Nevertheless, in accordance with most experts, the authors recommend patients presenting 24 hours or more after injury with no clinical signs of infection can be excluded from prophylaxis, whereas those with deep bites, with crushed tissues, or puncture wounds resulting notably from cat bites, facial bites, any wound over a tendon or bone, and immune-compromised patients should receive empirical prophylaxis with amoxicillin-clavulanic acid for between 2 to 5 days (Figure 2).^1,8 In this work, use of antibiotic prophylaxis was frequent and was not influenced by the delay between injury and consultation. Furthermore, the mean duration of antibiotic prophylaxis was 7 days, which is more than recommended. These results suggest that antibiotic use following animal bites at EDs in Marseille requires standardization. 

The authors thank Karolina Griffiths for editing the manuscript.

Affiliation: Institut Méditerranée Infection, Marseille, France

Correspondence:
Philippe Gautret, MD, PhD
Institut Méditerranée Infection
philippe.gautret@club-internet.fr

Disclosure: The authors disclose no financial or other conflicts of interest.