Epidemiologic, clinical, and therapeutic aspects of formally identified Echis romani bites in northern Cameroon

Abstract Background Species of the genus Echis, particularly those of the 'ocellatus' group, are responsible for the majority of snakebite envenomations and deaths in the savannas of sub-Saharan Africa. In a clinical study conducted in Cameroon, we treated a series of patients bitten by formally identified E. romani. The clinical outcomes are described and discussed. Methodology/Principal findings Specimens brought in by the victim were identified by a herpetologist. Clinical description and therapeutic management followed a standardized protocol applied by trained physicians. We included 92 patients, 95% of whom (n = 87) were envenomated. More than one third of the bites occurred during agricultural work, and one quarter in the victim's home. The bite site was the foot in 48 victims (52%) and the hand in 40 others (43%), mostly children and teenagers. Cytotoxic syndrome was observed in 84 of the 87 envenomated patients (97%). Hemostasis disorders were observed in 78 patients (90%), 38 of whom (44%) experienced bleeding during hospitalization. In 5 of the latter (13%), the bleeding recurred, whereas it had stopped after antivenom administration. A further 7 patients, who were not bleeding on arrival, experienced late bleeding despite antivenom administration. Four patients (4.3%), including one pregnant woman, died. All were bleeding on arrival. Finally, 2 patients (2.2%) had permanent sequelae of moderate severity. Conclusion/Significance This study confirms the frequency and severity of hemorrhagic complications in E. romani envenomation. Lethality remains high despite antivenom treatment. Cytotoxic syndromes, present in 95% of victims, rarely progress to extensive necrosis. Author summary The Echis genus is responsible for the majority of envenomations and deaths in the savanna and grassland regions of sub-Saharan Africa. The authors examined and treated 92 patients bitten in northern Cameroon by E. romani –a species of the 'ocellatus' group– formally identified from the specimen brought by the victim. Five of them showed no symptoms of envenomation (5% dry bites). Of the 87 envenomated patients, 84 (97%) had a cytotoxic syndrome characterized by edema of varying severity. Hemostasis disorders were observed in 78 patients, 38 (49%) of whom experienced bleeding during hospitalization. Among the latter, 5 patients (13%) showed recurrence of bleeding after cessation of bleeding. Seven patients who were not bleeding on arrival experienced late bleeding despite antivenom administration. Four patients, all with bleeding, including one pregnant woman, died. Two others had permanent sequelae of moderate severity. This study confirms that E. romani is a major threat to the rural population of northern Cameroon due to hemorrhagic complications and, secondarily, the risk of motor disability from tissue necrosis.