Bothrops asper: the lethal velvet

The last three post were related to the 45th anniversary of the "Instituto Clodomiro Picado", Costa Rica. The TV program "ConCiencia" (that can be read as WithScience and also as Consciousness) consisting on two interviews by Mr. Gustavo Gutiérrez Espeleta: first to Dr. José Mª Gutiérrez, investigator of the ICP and professor of the Faculty of Microbiology at the University of Costa Rica and second, to Dr. Alberto Alape-Girón, the actual director of the Instituto. 

All the research done by Dr. Clodomiro started early last century. He was worried about the high number of deaths happening on the laborers, mostly in the banana plantations, due to snakebites. From the interview we know that the "Serpiente Terciopelo" (Velvet snake, Lance-head, Fer-de-Lance) Bothrops Asper, is most common snake, far away in number of envenomations from other snakes, responsible for those lethal envenomations. So, even if we are far away from that country, I would like to dedicate this post to know more about this snake.

In all North, Central and South América, the predominant venomous snakes are pit vipers. The only elapid that can be found in the Coral snake, also deathly venomous, but the number of bites is relatively low compared to pit-vipers.

Bothrops Asper:

This is the information we can get from the reptile database: 

http://reptile-database.reptarium.cz/species?genus=Bothrops&species=asper&search_param=%28%28search%3D%27bothrops+asper%27%29%29

Bothrops Asper, (Garman, 1883)

There is a kind of overlaping between the Bothrops Asper (B. Asper) and the Bothrops Atrox (B. Atrox), that made even in the fifties that this B. Asper was called B. atrox-asper by some herpetologist. 

Distribution:

S Mexico (Chiapas, Oaxaca, Veracruz, Puebla, Quéretaro, Hidalgo, San Luis Potosí, Hidalgo, Tamaulipas southwards), Guatemala, Honduras, Nicaragua, Costa Rica, Panama, Belize, Colombia (Valle del Cauca), W Ecuador, Venezuela; elevation (Honduras): 880-1160 m, 0-1500 m (Colombia).

(B. Atrox is found in South America only, not in Central America. Common names for B. Atrox are Barba amarilla, Fer-de-lance and common lancehead). In some countries as Colombia, both species coexist. 

Bothrops Asper

Named after Latin “asper” = rough, in reference to the nasty temper of the snake, or to the roughness of the keeled scales on the dorsum. 

Toxicon, Vol 54, Issue 7

Special issue: Bothrops asper,

from natural history to public health

Natural history of the terciopelo Bothrops asper (Serpentes: Viperidae) in Costa Rica

Toxicon, Vol 54, Issue 7, Pages 904–922
Mahmood Sasa, Dennis K. Waskob, William W. Lamarc
Instituto Clodomiro Picado, Universidad de Costa Rica, San José, Costa Rica 

Department of Biology, University of Miami, Coral Gables, FL 33124 USA
Department of Biology, The University of Texas at Tyler, TX 75799, USA

http://dx.doi.org/10.1016/j.toxicon.2009.06.024

Abstract 

The terciopelo Bothrops asper is the only lancehead species widely distributed in the humid lowlands of Middle America and northwestern South America. Its large body size, relative abundance and cryptic habits contribute to the high incidence of snakebites induced by this species throughout its distribution. The terciopelo plays an important role in ecosystems, both as prey and as a generalist predator. Diet comprises a great variety of prey items, including some species that are considered nuisances. B. asper, as other lancehead species, exhibits a notable ontogenetic shift in diet, consuming ectotherms (mainly frogs and lizards) when young, and increasingly incorporating birds, rodents, and other small mammals with maturity. Adult terciopelos also consume large anurans, especially when endothermic prey availability is low. 

Using radiotelemetry we determined home range and movement patterns from 28 individual B. asper at La Selva Biological Station, Costa Rica. Overall home range estimates are relatively small compared with other pitvipers, averaging between 3.71 ha and 5.95 ha; home range size did not differ between males and females. Movement patterns are largely aseasonal and consist of short (<10 m) movements between daytime shelter and nocturnal ambush sites within a given area, interspersed with longer distance (>50 m) movements to new foraging areas. Habitat use is related to prey availability and therefore to foraging strategy. Our data support a strong preference for areas near swamps by both sexes. 

Reproduction in B. asper is highly seasonal, and – apparently – biannual. Reproductive cycles in Costa Rica are tightly related to rainfall patterns. Therefore, the timing of breeding differs between populations in the Caribbean and Pacific lowlands. Bothrops asper is adapted to areas with low levels of disturbance along the agricultural frontier, and consequently it is not rare to find it in or near human dwellings. However, despite popular belief, no evidence supports a purported increase in population density of this species in Costa Rica. Despite human persecution and substantial modification of habitat, B. asper is a species with a conservation status of least concern, and probably will likely persist well into the future. Thus, it is important to learn how to coexist with this species, and to improve mechanisms for the prevention and treatment of accidental snakebite and its consequences. 

Epidemiological, clinical and therapeutic aspects of Bothrops asper bites

Toxicon, Vol 54, Issue 7, 1 December 2009, Pages 998–1011
Rafael Otero-Patiño,
Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
http://dx.doi.org/10.1016/j.toxicon.2009.07.001

Abstract

Bothrops asper inflicts the majority of snakebites in Central America and in the northern regions of South America, mostly affecting young agricultural workers in rural settings. This species is capable of provoking severe envenomings associated with local and systemic manifestations. The main clinical features are: 

• local edema, 
• ecchymoses, blisters, dermonecrosis, 
• myonecrosis, 
• defibrinogenation, thrombocytopenia, systemic bleeding, 
• hypotension and renal alterations. 
• In addition, soft-tissue infection, acute renal failure, compartmental syndrome, central nervous system hemorrhage and, in pregnant women, abortion, fetal wastage and abruptio placentae have been described as complications. 

Intravenous administration of antivenom constitutes the mainstay in the therapy. Antivenoms composed of either whole IgG or F(ab′)2 fragments, manufactured in Brazil, Colombia, Costa Rica and Mexico, have been tested in controlled clinical trials, and rational protocols for antivenom administration have been developed. In addition to antivenom therapy, a number of ancillary interventions are recommended in the treatment of B. asper bites.

Studies on the venom proteome of Bothrops asper: Perspectives and applications 

Toxicon, Vol 54, Issue 7, 1 December 2009, Pages 938-948

Alberto Alape-Girón, Marietta Flores-Díaza, Libia Sanzd, Marvin Madrigal, José Escolano, Mahmood Sasa, Juan J. Calvete.

Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica

Departamento de Bioquímica, Escuela de Medicina, Universidad de Costa Rica

Centro de Investigaciones en Estructuras Microscópicas, Universidad de Costa Rica,

Instituto de Biomedicina de Valencia, C.S.I.C., Jaume Roig 11, 46010 Valencia, Spain

http://dx.doi.org/10.1016/j.toxicon.2009.06.011

Abstract

Bothrops asper is responsible for the vast majority of snakebite accidents in Central America and several studies have demonstrated that specific toxic and enzymatic activities of its venom vary with the geographic origin and age of the specimens. 

Variability in venom proteins and enzymes between specimens from the Caribbean and the Pacific versants of Costa Rica has been reported since 1964. Recently, we performed a comparative proteomic characterization of the venoms from one population of each versant. Proteins belonging to several families, including 

• Disintegrin, 
• Phospholipases A2, 
• serine proteinases, 
• C-type lectins, 
• CRISP, 
• L-amino acid oxidase, and 
• Zn2+-dependent metalloproteinases 

show a variable degree of relative occurrence in the venoms of both populations. The occurrence of prominent differences in the protein profile between venoms from adults and newborns, and among venom samples from individual specimens of the same region or developmental stage, further demonstrated the existence of geographic, ontogenetic and individual variability in the venom proteome of this species. These findings provide new insights towards understanding the biology of B. asper, contribute to a deeper understanding of the pathology induced by its venom and underscore the importance of the use of venoms pooled from specimens from both regions for producing antivenom exhibiting the broadest cross-reactivity. Furthermore, knowledge of the protein composition of B. asper venom paves the way for detailed future structure–function studies of individual toxins as well as for the development of new protocols to study the reactivity of therapeutic antivenoms.

There is a beautiful documentary on some Snakes of Costa Rica. The search for the giant lance-head pit viper on the mountains of Costa Rica. 

Austin Stevens: In Search of The Ultimate Pit Viper. 
You can find it easily on Youtube.
Austin Stevens, a wildlife photographer, specialized on snakes receives the assignment to photograph a giant lance-head, the "terciopelo" snake, in Costa Rica. You will see how he treats the snakes and how snakes behave. Some are quite calm, almost do not try to bite like the "cuba" that appears at the beginning. The views of the nature are amazing. In the video you will see very clearly the very brave temperament of the Terciopelo as well as the huge fangs it has! I would like to know from where the name is coming from, as asper means exactly the opposite to velvet... ¿?

This new appeared on the newspaper "La Nación", of Costa Rica, 19 Jan. 2015. Article by Hugo Solano. http://www.nacion.com/sucesos/Mordedura-serpiente-acabo-vida-agricola_0_1464453690.html
Beyond documentaries, snakebites are still a crude reality for many laborers.

Valentino Barrantes, 54 years old died after the bite of a "terciopelo" snake. He was working at the farm when was bitten. Even if he was wearing boots, the fangs of the snake went through them and bite him on the left toe. Another worker went after the snake, kill it and after that runned 1,5 km to the road and looked for the help of the Red Cross. When they arrived, Mr. Barrates was already death.

Important: Do not waste time at avoid putting yourself at risk looking and trying kill the snake responsible of the bite. Put the victim on a safe place and run for help!

Photo of the deceased appeared in "Diario Extra", José Brenes, correspondent

Here is a sadly famous image of the leg of a boy bitten by a Bothrops asper. 

Extensive Tissue Necrosis of the Lower Limb in an 11-Year-Old Boy Who Had Been Bitten Two Weeks Earlier by a B. asper in Ecuador

Only antibiotic treatment had been given, so tissue damage was extensive, requiring above-knee amputation. Such pathological alterations are caused by the direct action of locally acting toxins in the venom (mostly metalloproteinases and phospholipases A₂), together with an indirect effect promoted by local inflammatory events and ischemia secondary to venom-induced vascular damage and increased intracompartmental pressure. (Image: D. A. Warrell)

http://dx.doi.org/10.1371/journal.pmed.0030150.g002

ॐ लोकाः समस्ताः सुखिनो भवन्तु ॥

Om Lokah Samasthah Sukhino Bhavantu

May all beings everywhere be happy and peaceful.