Comment on clinical features of 27 shark attack cases on La Réunion Island
The authors of the article pointed out that there was no published data that validates a specific course of prophylactic antibiotics. However, Caldicott et al.,1 cited by the authors, recommend the empirical antibiotic treatment for all shark bites and emphasized that the choice of antibiotics should cover for Vibrio species with a third generation of cephalosporin or ciprofloxacin treatment, and Aeromonas species with imipenem or an aminoglycoside. Buck et al.2 succeeded to isolate various Bacteria species and performed antibiotic susceptibility tests on isolates and presented a table for guidance in antibiotic choice for clinicians. Then, there is Royle et al.3 who presented two shark bite infection cases from which they isolated Vibrio parahemolyticus, V. alginolyticus, Aeromonas caviae, and A. hydrophila, where the latter is consistent with the other studies. They suggest the use of cefotaxime, metronidazole, and ciprofloxacin in such cases. Furthermore, in a relatively recent study, Interaminense et al.4 identified 81 potential bacterial pathogens in the oral cavity of sharks, subjected them to antibiotic susceptibility tests, and reported successful treatment of three shark bite infection cases. Similarly, Unger et al.5 isolated a total of 49 bacteria species consisting of 22 different genera from 19 live blacktip sharks (Carcharhinus limbatus). In that study Gram-negative bacteria comprised of a significantly higher proportion of the isolated bacteria; predominately consisted of Vibrio alginolyticus, other Vibrio species and Pasteurella sp., and also gram-positive organisms included a composite of various coagulase-negative Staphylococcus species and Bacillus sp. From the antibiotic susceptibility testing results, empiric treatment with either a fluoroquinolone or combination of a 3rd generation cephalosporin plus doxycycline was recommended.
Beside prophylactic antibiotics, there are some actual errors in the statistical presentation in this study. It was concluded that the “… human-shark contacts increased in recent years …” such a statement is incorrect since the number of people entering the water, or any other proxy that makes a comparison between contacts and the overall number of exposed people is unknown. The rather constant number of yearly bites (e.g., Global Shark Attack File, 2017) actually suggests otherwise, considering the increase of human population, compared with the numbers of incidents.6–8 It also needs to be highlighted that not every shark bite qualifies for inclusion in such tendencies, for example, year after year, people get bitten because they spear fish. Such practice lures in sharks, and a bite does then bias the presented number of incidents. It was also concluded that the mortality rate "… decreased because of the presence of lifeguards and rapid transport to a trauma center …” is another invalid statement since no connection to e.g., number of hospitals per shore distance then and now, or similar, was given. Then the authors mentioned “… sites that have a high risk of shark attacks …” The expression “high risk” is not qualitative as long as it does not compare bite numbers to, for example, beachgoing population for said area, or any other proxy that allows a true comparison. Thus the overall conclusion how La Réunion measures up against other areas needs to be differently described. Then there is the statement that the attack rate in La Réunion is 15 times higher than in South Africa, 14 times higher in the United States, and so on. Here as well, no mentioning is made how large the pool of beachgoing humans, or any relevant proxy that the number of bites can be measured against, was for South Africa, United States and so on, thus it cannot be concluded that La Réunion has a higher bite rate.