The South-American rattlesnake Crotalus durissus: feeding ecology in the central region of Brazil

Hoyos, María A.; Almeida‐Santos, Selma Maria

doi:10.1590/1676-0611-bn-2014-0027

Cited by 11 publications

(5 citation statements)

References 22 publications

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“…Such age-driven changes in venom composition are generally thought to stem from shifts in prey preference between juvenile and adult snakes ( 10 , 121 , 122 ), as seen in a variety of snakes ranging from Australian elapids ( 110 ) to lancehead pit vipers of the genus Bothrops ( 113 , 125 ). However, our current knowledge—albeit fragmentary—points to C. durissus, C. simus , and C. tzabcan being rodent specialists throughout their life ( 10 , 24 , 126 – 129 ). While only scarce information is available for C. culminatus , reports indicate a rodent-centered diet as well ( 10 , 23 , 24 , 130 ).…”

Section: Discussionmentioning

confidence: 99%

A Clot Twist: Extreme Variation in Coagulotoxicity Mechanisms in Mexican Neotropical Rattlesnake Venoms

et al. 2021

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Rattlesnakes are a diverse clade of pit vipers (snake family Viperidae, subfamily Crotalinae) that consists of numerous medically significant species. We used validated in vitro assays measuring venom-induced clotting time and strength of any clots formed in human plasma and fibrinogen to assess the coagulotoxic activity of the four medically relevant Mexican rattlesnake species Crotalus culminatus, C. mictlantecuhtli, C. molossus, and C. tzabcan. We report the first evidence of true procoagulant activity by Neotropical rattlesnake venom in Crotalus culminatus. This species presented a strong ontogenetic coagulotoxicity dichotomy: neonates were strongly procoagulant via Factor X activation, whereas adults were pseudo-procoagulant in that they converted fibrinogen into weak, unstable fibrin clots that rapidly broke down, thereby likely contributing to net anticoagulation through fibrinogen depletion. The other species did not activate clotting factors or display an ontogenetic dichotomy, but depleted fibrinogen levels by cleaving fibrinogen either in a destructive (non-clotting) manner or via a pseudo-procoagulant mechanism. We also assessed the neutralization of these venoms by available antivenom and enzyme-inhibitors to provide knowledge for the design of evidence-based treatment strategies for envenomated patients. One of the most frequently used Mexican antivenoms (Bioclon Antivipmyn®) failed to neutralize the potent procoagulant toxic action of neonate C. culminatus venom, highlighting limitations in snakebite treatment for this species. However, the metalloprotease inhibitor Prinomastat substantially thwarted the procoagulant venom activity, while 2,3-dimercapto-1-propanesulfonic acid (DMPS) was much less effective. These results confirm that venom-induced Factor X activation (a procoagulant action) is driven by metalloproteases, while also suggesting Prinomastat as a more promising potential adjunct treatment than DMPS for this species (with the caveat that in vivo studies are necessary to confirm this potential clinical use). Conversely, the serine protease inhibitor 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) inhibited the direct fibrinogen cleaving actions of C. mictlantecuhtli venom, thereby revealing that the pseudo-procoagulant action is driven by kallikrein-type serine proteases. Thus, this differential ontogenetic variation in coagulotoxicity patterns poses intriguing questions. Our results underscore the need for further research into Mexican rattlesnake venom activity, and also highlights potential limitations of current antivenom treatments.

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Section: Discussionmentioning

confidence: 99%

A Clot Twist: Extreme Variation in Coagulotoxicity Mechanisms in Mexican Neotropical Rattlesnake Venoms

et al. 2021

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“…Interestingly Mise et al (2007) showed that, although Bothrops are nocturnal snakes, most cases registered in the state of Bahia occurred during the day, showing the greater contact of man with these animals in periods of foraging and thermoregulation. In Brazil, the genus Crotalus is widely distributed and has a diet characterized by an extreme specialization in endothermic preys, such as rodents, because of its abundance throughout the year (Hoyos & Almeida-Santos, 2016). Our study revealed the wide distribution of Crotalus in the state of Ceará and the literature has already described that these snakes tend to occupy areas disturbed by human activities, which include landscape mosaics as original habitats, new environments and urban and agricultural areas.…”

Section: Resultsmentioning

confidence: 52%

Spatial distribution of snakebites in the State of Ceará, Brazil (2008-2018)

Braga

Ramalho

Sousa

et al. 2021

RSD

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Snakebites represent an important, though neglected, public health problem especially in the Northeast of Brazil. There is still a large number of underreported cases, the collection of epidemiological data is deficient, and the ecological and epidemiological knowledge of this envenomation remains limited due to the lack of updated regional and local information. This study describes the epidemiological profile of snakebites recorded by the Notifiable Diseases Information System from 2008 to 2018 in the state of Ceará. The data were organized according to the municipalities of the health macro-regions, considering the variables: sex, snake, gravity and deaths. A total of 8,233 cases was found, with an annual incidence of 8.6/100,000 inhabitants, and a higher prevalence of accidents caused by Bothrops snakes (64%), in men (87.4%) in the Sobral region (25.5%). However, the highest incidence rate was found in the Sertão Central (299.7/100,000). Most cases were considered mild (62%), but the mortality rate was 0.07/100,000 and the case-fatality rate was 0.8%. Among the most affected municipalities, cities like Tauá (1.3%), Sobral (8.1%) and Fortaleza (8.5%) are concerning, considering that the case-fatality rates were above the national average (1%). Snakebites in Ceará follow a pattern similar to that of other states in the Northeast, with a high frequency of incidents where the causative snake is not identified (16%). Considering the gravity of snakebites, studies that evaluate the anthropic and environmental influence in the distribution of cases may help to define priority risk areas, to improve health surveillance and patient care.

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“…C. durissus is terrestrial and hunts mainly by waiting for rodents ( 20 , 21 , 27 ) ( Figure 2F ). Small mammals, mainly rodents, make up most of the diet of C. durissus in the southeastern ( 27 , 28 ) and central regions ( 29 ) of Brazil, though lizards ( Ameiva ameiva ) are also consumed in a smaller proportion. Birds have also been recorded in the diet of northeastern populations ( 30 ) ( Figure 2D ).…”

Section: Crotalus Durissus Ruruima : Natural Historymentioning

confidence: 99%

Crotalus Durissus Ruruima: Current Knowledge on Natural History, Medical Importance, and Clinical Toxinology

Pucca

Bernarde

Rocha³

et al. 2021

Front. Immunol.

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Crotalus durissus ruruima is a rattlesnake subspecies mainly found in Roraima, the northernmost state of Brazil. Envenomings caused by this subspecies lead to severe clinical manifestations (e.g. respiratory muscle paralysis, rhabdomyolysis, and acute renal failure) that can lead to the victim’s death. In this review, we comprehensively describe C. d. ruruima biology and the challenges this subspecies poses for human health, including morphology, distribution, epidemiology, venom cocktail, clinical envenoming, and the current and future specific treatment of envenomings by this snake. Moreover, this review presents maps of the distribution of the snake subspecies and evidence that this species is responsible for some of the most severe envenomings in the country and causes the highest lethality rates. Finally, we also discuss the efficacy of the Brazilian horse-derived antivenoms to treat C. d. ruruima envenomings in Roraima state.

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The South-American rattlesnake Crotalus durissus: feeding ecology in the central region of Brazil

Cited by 11 publications

References 22 publications

A Clot Twist: Extreme Variation in Coagulotoxicity Mechanisms in Mexican Neotropical Rattlesnake Venoms

A Clot Twist: Extreme Variation in Coagulotoxicity Mechanisms in Mexican Neotropical Rattlesnake Venoms

Spatial distribution of snakebites in the State of Ceará, Brazil (2008-2018)

Crotalus Durissus Ruruima: Current Knowledge on Natural History, Medical Importance, and Clinical Toxinology

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