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Background In tropical areas, a major concern regarding snakebites treatment effectiveness relates to the failure in liquid antivenom (AV) distribution due to the lack of an adequate cold chain in remote areas. To minimize this problem, freeze-drying has been suggested to improve AV stability. Methods and findings This study compares the safety and efficacy of a freeze-dried trivalent antivenom (FDTAV) and the standard liquid AV provided by the Brazilian Ministry of Health (SLAV) to treat Bothrops, Lachesis and Crotalus snakebites. This was a prospective, randomized, open, phase IIb trial, carried out from June 2005 to May 2008 in the Brazilian Amazon. Primary efficacy endpoints were the suppression of clinical manifestations and return of hemostasis and renal function markers to normal ranges within the first 24 hours of follow-up. Primary safety endpoint was the presence of early adverse reactions (EAR) in the first 24 hours after treatment. FDTAV thermal stability was determined by estimating AV potency over one year at 56°C. Of the patients recruited, 65 and 51 were assigned to FDTAV and SLAV groups, respectively. Only mild EARs were reported, and they were not different between groups. There were no differences in fibrinogen (p = 0.911) and clotting time (p = 0.982) recovery between FDTAV and SLAV treated groups for Bothrops snakebites. For Lachesis and Crotalus snakebites, coagulation parameters and creatine phosphokinase presented normal values 24 hours after AV therapy for both antivenoms. Conclusions/Significance Since promising results were observed for efficacy, safety and thermal stability, our results indicate that FDTAV is suitable for a larger phase III trial. Trial registration ISRCTNregistry: ISRCTN12845255; DOI: 10.1186/ISRCTN12845255 (http://www.isrctn.com/ISRCTN12845255)., Author summary Antivenoms (AV) are included in the WHO List of Essential Medicines, being the only treatment available for snakebites envenomings. In Brazil, five types of liquid snake AVs are distributed by the Ministry of Health for national use free of charge to patients. In remote areas, lack of an adequate cold chain impairs AV distribution to health facilities resulting in delay in patient care and, ultimately, in higher complication and case fatality rate. To minimize this problem, a freeze-drying process has been suggested to improve the stability of AVs, but freeze-dried AVs efficacy and safety evidence obtained from clinical trials is still very limited. Freeze-drying is a process by which water is removed from a sample without the need to apply heat. Benefits of lyophilization are: a) Samples are processed in aseptic conditions; b) Process does not use heat, ensuring formulation stability; c) Increases shelf life; d) Samples can be stored at room temperature for a long time; and e) Reduces weight and volume of samples, which is ideal for distribution. In this study, a freeze-dryed formulation is presented as a good alternative for a more stable trivalent antivenom in regions of the Amazon where high temperatures are common and the cold chain is poor. Our results suggest that such a product is adequate for a phase III trial.

Contact with Lonomia caterpillars can cause a hemorrhagic syndrome. In Brazil, Lonomia obliqua and Lonomia achelous are known to cause this venom-induced disease. In the Brazilian Amazon, descriptions of this kind of envenomation are scarce. Herein, we report a severe hemorrhagic syndrome caused by Lonomia envenomation in the Amazonas state, Western Brazilian Amazon. The patient showed signs of hemorrhage lasting 8 days and required Lonomia antivenom administration, which resulted in resolution of hemorrhagic syndrome. Thus, availability of Lonomia antivenom as well as early antivenom therapy administration should be addressed across remote areas in the Amazon.

Micrurus snakes, commonly known as coral snakes, are responsible for 0.4% of the snakebites envenomings in Brazil. In this report, we describe a case of envenoming by Micrurus averyi, the black-headed coral snake, recorded in the western Brazilian Amazon. To the best of our knowledge, this is the first published case perpetrated by this species. The major complaint of the patient was an intense local pain and paresthesia. Examination of the bite site revealed edema extending from the left foot up the left leg that was accompanied by erythema involving the foot and distal third of the leg. Systemic signs at admission included nausea and drooling. The patient was treated with 100 mL of coral snake antivenom and intravenous analgesics (dipyrone) and was discharged 48 h post-admission with no complaints. The patient showed more intense local edema than that generally described in several other cases of Micrurus bites in Brazil.

INTRODUCTION: Snake bite, a problem in public health, generally occurs where there is no electric power. METHODS: A comparative clinical study was conducted with 102 victims of Bothrops snake bite, from the state of Amazonas, Brazil; 58 victims were treated with liofilizated trivalent antivenom serum (SATL) and 44 victims treated with liquid bivalent and monovalent antivenom serum (SAMBL). RESULTS: 17% (10/58) of patients presented adverse effects with the SATL and 25% (11/44) with the SAMBL. CONCLUSIONS: There was no statistic difference in number of adverse effects between the two types of snake bite antivenom. INTRODUÇÃO: Acidente ofídico, problema de Saúde Pública, é mais frequente onde não há energia elétrica. MÉTODOS: Foi realizado estudo clínico comparativo com 102 vítimas de acidente botrópico, do Estado do Amazonas, Brasil; 58 vítimas tratadas com soro antiofídico trivalente liofilizado (SATL) e 44 vítimas tratadas com soro antiofídico monovalente e bivalente líquido (SAMBL). RESULTADOS: A comparação entre os tipos de soro demonstrou 17% (10/58) de indivíduos com eventos adversos com o uso de SATL e 25% (11/44) com o uso dos SAMBL. CONCLUSÕES: Não houve diferença estatística na quantidade de reações adversas entre os dois tipos de soros antiofídicos.