Showing posts with label Daboia russelii. Show all posts
Showing posts with label Daboia russelii. Show all posts

Wednesday, March 7, 2012

Systematics of Confused North African Macrovipers

Daboia mauritanica, Casablanca. Photo Credit: Gabri Mtnez
In North Africa, three species of large paleartic vipers have been recorded: Daboia mauritanica (Duméril & Bibron, 1848), D. deserti (Anderson, 1892) and Macrovipera lebetina transmediterranea Nilson & Andrén 1988. The latter has never been recorded accurately after its description, and it has never been included in any recent phylogenetic analysis. The taxonomic status of deserti is neither clear as a species, subspecies or just a morphological variation of D. mauritanica. Further research with genetic phylogenies with a wide sampling all over northwest Africa, is necessary to clarify the identity and taxonomic position of the taxa transmediterranea and deserti. Hopefully in the near future the population structure of this species complex will become better known.

Citation
Octavio Jiménez Robles & Gabriel Martínez del Mármol Marín: Comments on the large paleartic vipers Macrovipera and Daboia in North Africa. Published on March 05, 2012. Available from http://blog.moroccoherps.com/vipers-macrovipera-and-daboia-in-north-africa.
Accessed March 07, 2012.

Monday, January 23, 2012

Daboia Envenomation and the Pituitary Gland

The Russell’s vipers (Daboia russelii and D. siamensis) inhabit South and South East Asian, they are large and dangerous and do not hesitate to bite. Tun-Pe et al. (1987) suggested that envenomation by Russell's vipers could produce a disorder that resembled Sheehan’s syndrome. They investigated pituitary function in nine patients that were in shock after envenomation by Russell's viper and another 24 individuals who had been severely envenomed two weeks to 24 years prior to the study. Three out of the nine patients had hypoglycemia and inappropriately low serum cortisol, plasma growth hormone, and plasma prolactin concentrations. Four who died showed pituitary hemorrhage and one had adrenal hemorrhage. Of the 24 who had apparently recovered from bites, seven had clinical symptoms of hypopituitarism and no response in plasma growth hormone or prolactin concentrations to symptom-producing insulin-induced hypoglycemia. Four men with symptoms showed low serum testosterone concentrations; serum thyroxin was also low in these men but not in two women with menstrual disturbances and impaired insulin responses. Of the 17 individuals without clinical evidence of endocrine disease, and four had pituitary hormonal abnormalities.

In 2011, Antonypillai and colleagues found people envenomed by Russell’s vipers suffer coagulopathy, bleeding, shock, neurotoxicity, acute kidney injury and local tissue damage leading to severe morbidity and mortality; and report the unusual complication of hypopituitarism. They described the first case of hypopituitarism following Russell’s viper bite in Sri Lanka. A 49-year-old man bitten and seriously envenomed by D. russelii in 2005 was treated with antivenom, recovered from the acute effects but remained unwell. Three years later hypopituitarism, with deficiencies of gonadal, steroid and thyroid axes was diagnosed and he showed marked improvement after replacement of anterior pituitary hormones. The authors attributed the hypopituitarism to Daboiai envenomation. Russell’s viper venom is known to cause acute and chronic hypopituitarism and diabetes insipidus, possibly through deposition of fibrin microthrombi and hemorrhage in the pituitary gland that result from the action of procoagulant enzymes and haemorrhagins in the venom. Forty nine cases of hypopituitarism following Russell’s viper bite have been described in the literature. More than 85% of these patients suffered acute kidney injury immediately after the bite, but steroid replacement in acute hypopituitarism is lifesaving.

Although the pituitary gland regulates puberty, it continues to function throughout a person's life and damage can result in failure of the gland to produce the needed hormones. Envenomation by Russell's Vipers often result in significant damage to the gland and hypopituitarism or Sheehan's Syndrome, as suggested by these two studies. Both conditions have symptoms, such as a constant feeling of cold and an unusual amount of fatigue, but what distinguishes them is a loss sex drive, fertility, body hair, and muscle mass (especially pubic hair), while women lose their body shape as they lose weight, and some may lose cognitive skills as the condition progresses.

Citations
Antonypillai CN., Wass, JAH., Warrell, DA, and Rajaratnam, HN. 2011. Hypopituitarism following envenoming by Russell’s Vipers (Daboia siamensis and D. russelii) resembling Sheehan’s syndrome: first case report from Sri Lanka, a review of the literature and recommendations for endocrine management. Oxford Journal of Medicine, 104: 97-108.

Tun-Pe, Warrell DA., Tin Nu, S. Phillips, RE., Moore, RA. 1987. Acute and chronic pituitary failure resembling Sheehan's syndrome following bites by Russell's Vipers in Burma. The Lancet 330: 763-767.

Saturday, March 5, 2011

This Russell’s Viper Survived the Perils of Plastic


The Deccan Herald is carrying the following story.

This Russell’s viper survived the perils of plastic
Subhash Chandra N S Bangalore, March 5, DHNS
Reckless disposal of plastic waste almost proved fatal for a venomous Russell’s viper that was found struggling for life near Kengeri. Some passersby recently found the two-foot viper writhing in pain and alerted the People for Animals (PFA), a city-based organisation of animal rights activists.

A PFA volunteer, who rushed to the spot, said he found the viper gasping for breath. Dr Vetrivelu, attached to the PFA, said: “First we thought it was injured, but later, we found something stuck in its mouth.”

As Russell’s viper is venomous, it was sedated before close examination, he said. “We pulled out a piece of a polyethene bag stuck in its jaws. We used forceps and pulled out three more pieces of the polyethene bag that were not less than two feet,” the doctor said.

t took nearly three days for the snake to recover. Suffering from severe dehydration, the viper, weighing about 180 gm, was treated with ringers lactate and normal saline (to prevent dehydration) and ‘subcutane’ (to strengthen the vital organs) for about four days before releasing it into Turhalli forest.

Herpetologists “Snake” Shyam of Mysore and Gowri Shankar say sometimes snakes consume things bigger than their size.

“I once found a snake which had swallowed two metres of cloth,” said Shyam. Shankar said snakes tended to devour anything that smelt like rat or eggs.