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Envenomation by coral snakes represents a little known burden in Brazilian Amazonia. So far, details on clinical and epidemiological aspects remain obscure in the region. We gathered data from medical charts and from the scientific collection of snakes from Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, finding 26 cases of envenomation by five species of Micrurus in Manaus region, between 1987 and 2018. They represent 0.7% of the snakebites treated in the hospital since the records began, in 1979. Micrurus lemniscatus was responsible for most of the bites (10), followed by M. hemprichii (five), M. spixii (three), M. surinamensis (three) and M. averyi (one). There was no difference between the sexes of the snakes that caused bites. Patients were mostly males, and most of the cases were reported in urban areas. Bites predominated in dry season, and there was a clear geographical segregation among species. We describe seven cases of envenomation, three mild and four severe, all of which evolved to cure. Paresthesia (six), pain (five) and edema (four) were the most common local symptoms. Systemic features such as dyspnea/shallow breath (four), palpebral ptosis (four), blurred vision (three), dysarthria (three) and difficulty to walk (three) were also detected. Two patients bitten by Micrurus sp. and M. hemprichii, showed slight increased serum levels of creatine kinase (reference level190 U/L), 1184 U/L and 1229 U/L, respectively, indicative of mild systemic myotoxicity. This is the first report of myotoxic manifestation in the envenomation by M. hemprichii. No patient developed respiratory failure, though one bitten by an adult M. spixii required intubation and mechanical ventilation due to decreased level of consciousness during evolution, probably related to induced sedation caused by concurrent alcohol intoxication. All patients were treated with Brazilian Micrurus antivenom (soro antielapídico, median = 10 vials). Six patients were pretreated intravenously with H1 and H2 antagonists and steroids, with two patients developing early adverse reactions. The median length of hospital stay was four days. Envenomations by coral snakes in Manaus region are clinically severe, but rare and sparsely distributed over time, making the detection of epidemiological and clinical patterns a challenge for public health.

Coral snakes constitute a relatively diverse and little known group of venomous snakes. So far, data for this kind of snakebite in the Amazon region are based only on case reports. This study takes advantage of novel data from the Brazilian Health Ministry database from 2010 to 2015 and presents a review of the cases reported in the literature regarding the Amazonian biome both from Brazil and nearby countries. Thirty-four cases reported in the database were used in the study, representing 0.05% of the snakebites in Brazilian Amazonia for that period. The incidence rate was 0.123 cases/100,000 inhabitants/year. The most affected group is that of working age men, suggesting occupational risk. Most of bites were on lower limbs. Pain, edema and paresthesia were the most common symptoms. Systemic symptoms not usually associated with coral snakes envenomings, such as coagulopathy and thrombocytopenia, have been reported in Amazonia. Five patients received less antivenom than indicated by the Health Ministry. Based on these results, we recommend the execution of educational programs to avoid such accidents and to teach both the general public and health professionals the correct treatment for the bites. We also suggest that the covering of Intensive Care Units in the region needs to be improved to avoid deaths.

Bites by Micrurus snakes in Brazilian Amazon represent about 0.4% of snakebite registered in that area. There is not information available about the M. annellatus snakebites In this report, we describe a case of envenoming caused by Micrurus annellatus bolivianus recorded in the municipality of Cruzeiro do Sul, state of Acre, western Brazilian Amazon. On admission, the patient was suffering from mild pain, mild edema and paraesthesia restricted to the site of the bite, darkened vision and nausea. Laboratorial evaluation revealed unclottable blood which improved only after 3 days of follow-up. Envenoming was classified as moderate, and 50 ml of antielapid serum was administered. The next day after the incident, vital signs were normal and the patient had mild thrombocytopenia (133,000/mm3). The patient did not present any bleeding during the hospitalization. On the fourth day after admission, the patient was discharged alleging no complaints. The patient showed coagulopathy, a rare condition in cases of Micrurus bites. Some areas where there is a lack of knowledge on coral snakebites are listed in this manuscript.

Scorpion envenomations are a major public health problem in Brazil, and most medically important cases are attributable to the Tityus genus. The objective of this study is to describe the clinical and epidemiological aspects of a series of 151 cases of confirmed scorpion stings, which were treated at the hospitals of two cities in the Western Brazilian Amazon, between June 2014 and December 2019. This study shows that the genus Tityus was the most prevalent. Tityus (Atreus) metuendus (Pocock, 1897) was responsible for the greatest number of cases (68.2%), followed by Tityus (Archaeotityus) silvestris (Pocock, 1897) (14.6%). Most of the envenomations involved males (53.6%), and analysis showed a slight predominance in the group from 40 to 49 years (22.5%). The most affected body regions were feet (49.0%) and hands (31.8%). The time elapsed between the accident and medical care was ≤6 h in 92.1% of cases. Regarding clinical severity, classes I (80.8%) and II (15.9%) predominated. However, there were five (3.3%) class III cases; four for T. metuendus and one for T. silvestris. The most frequent local and systemic manifestations were, respectively, pain (84.1%), paresthesia (34.4%) and mild edema (25.8%), and nausea (9.3%) and myoclonia (8.6%). The clinical manifestations were similar among the patients stung by the different species of scorpions. There were no differences between the manifestations of envenomation caused by T. metuendus, T. silvestris and T. raquelae. For victims of T. apiacas, a higher frequency of piloerection and myoclonia was observed, and was described by the affected patients as a ‘sensation of receiving an electric shock’ throughout the body. No deaths were registered. The species of greatest epidemiological importance in Manaus is T. metuendus, a species that leads to clinical pictures that do not differ substantially from those observed in other Brazilian regions. T. apiacas causes neurological manifestations that differed from other Tityus species. Our findings suggest that the available antivenoms have little effectiveness when used in the treatment of envenomations by some Amazonian scorpions.

Snakebites by aglyphous or opisthoglyphous snakes are common in Brazil. We report a case of snakebite by the opisthoglyphous Erythrolamprus aesculapii. The victim presented with pain, edema, and bleeding at the bite site, along with erythema, similar to a Bothrops envenomation. In this type of snakebite, if the snake is not brought to the hospital, the victim may receive unnecessary serum therapy, with the risk of adverse reactions to the antivenom. The possibility of reducing after-effects with anti-inflammatory drugs and early antibiotic therapy for secondary infection need to be further investigated, preferably in multicenter studies, while observing good clinical practice.

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.