Cobra Antivenom Research Articles

Neutralization of the pharmacological effects of Cobra and Krait venoms by chicken egg yolk antibodies

Five-month-old white leghorn chickens were immunized with 50 μg of Common Cobra ( Naja naja) and 30 μg of Krait venoms ( Bungarus caeruleus) to generate antivenom antibodies against the venom antigen. Chickens received booster doses of increasing concentrations of venom at 14 days time intervals to raise the antivenom level in egg yolk. The antivenom from immunized chicken egg yolk was extracted by polyethylene glycol (PEG) and ammonium sulphate precipitation method which was further purified by DEAE cellulose ion exchange column chromatography. A high molecular weight protein of 180 kDa was detected by electrophoretic analysis which shows the purity of antivenom generated in chicken. Antibodies generated were specific and sensitive to the venom antigen. Various pharmacological activities of Cobra and Krait venoms were carried out by both in-vivo and in-vitro methods. The neutralization of lethality, hemorrhagic, edema, PLA 2 and procoagulant activity was evaluated in assays involving pre-incubation of venom and antivenom prior to testing. The antivenom was effective in neutralizing the toxic and enzymatic activities of venom. The LD 50 of venom for 18 g of mice was found to be 10 μg for Cobra and 3 μg for Krait venoms. The median effective dose (ED 50) of anti-Cobra venom was 4.48 mg/5LD 50 and 1.0 ml neutralized 0.127 mg of Cobra venom and the median effective dose (ED 50) of anti-Krait venom was 3.18 mg/5LD 50 and 1.0 ml neutralized 0.051 mg of Krait venom. The results indicate that antivenom generated in chicken could be used for therapeutic purposes in case of snakebite envenomation.

Treatment of the first known case of king cobra envenomation in the United Kingdom, complicated by severe anaphylaxis

We report the first known case of envenomation following snake bite by a king cobra in the UK. The patient required tracheal intubation and ventilation. Treatment with king cobra antivenom resulted in anaphylaxis (bronchospasm and hypotension), requiring adrenaline infusion. The patient's trachea was extubated 11 h after administration of antivenom.

Screening of plants containing Naja naja siamensis cobra venom inhibitory activity using modified ELISA technique

Enzyme-linked immunosorbent assay (ELISA) has been modified for screening plants with antagonistic activity to Naja naja siamensis cobra venom. Aqueous extracts from plants were investigated for their inhibitory effects on the binding of anti-cobra venom antibody to antigen, cobra venom, fixed onto 96-well microtiter plates. Ingredients in extracts were allowed to react with immobilized venom before the subsequent addition of antivenom antibody. Venom components affected by exposure to the extracts, unable to interact with their specific antibody, were predicted to be unable to bind to their native destinations or natural receptors. Curcuma cf. zedoaria, an old Thai medicinal plant, showed clear inhibitory activity in the ELISA test. Neurotoxin and protein degradative enzymes, major components in venom, were identified as targets of this extract in Western immunoblotting analysis. Ingredients in the extract showed high affinity to the toxin in competition assay by immunoprecipitation. The extract attenuated toxin activity by extending contraction time of diaphragm muscle after envenomation and had a potency to protect cellular proteins from venom degradative enzymes. Curcuma parviflora, with less activity in ELISA, exhibited acceptable results in two experiments but negative results in two experiments, whereas Curcuma longa, having low activity in the ELISA test, never showed any favorable results. Screening of 36 samples could classify plants into an inhibition range of 0 to 86%. This modified ELISA is recommended as a preliminary screening method for inhibitors with a large number of samples.

Antihemorrhagin in the blood serum of king cobra ( Ophiophagus hannah): purification and characterization

King cobra ( Ophiophagus hannah) serum was found to possess antihemorrhagic activity against king cobra hemorrhagin. The activity was stronger than that in commercial king cobra antivenom. An antihemorrhagin has been purified by ion exchange chromatography, affinity chromatography and gel filtration with a 22-fold purification and an overall yield of 12% of the total antihemorrhagic activity contained in crude serum. The purified antihemorrhagin was homogeneous in disc-PAGE and SDS–PAGE. Its apparent molecular weight determined by SDS–PAGE was 120 kDa. The antihemorrhagin was also active against other hemorrhagic snake venoms obtained in Thailand and Japan such as Calloselasma rhodostoma, Trimeresurus albolabris, Trimeresurus macrops and Trimeresurus flavoviridis (Japanese Habu). It inhibited the proteolytic activity of king cobra venom. It is an acid- and thermolabile protein and does not form precipitin lines against king cobra venom.

Restoration of adenosine deaminase, histamine, and IgE in organs of mice injected with cobra venom followed by specific treatment and reversal period

Adenosine deaminase (ADA), histamine, and IgE are endogenously present in animals. Research from this laboratory reported decreased levels of these substances in organs of mice as a consequence of sub-lethal injection of Naja kaouthia venom. This research reports that decreased ADA, histamine, and IgE levels were prevented by specific treatment and prolonged recovery periods. Adult Balb/c mice injected IM with sub-lethal venom dose were divided into five groups. Group 1 were injected with PBS; Group 2 with anti-cobra venom; and Group 3 with lethal toxin neutralizing factor (LTNF). Groups 4 and 5 were treated with IM or oral synthetic LT-10. After 24 hours, mice were sacrificed and organ homogenates were assayed for ADA, histamine, and IgE. Group 1 showed substantial reduction in levels of these substances. It was revealed that decreased levels were prevented by treatment with anti-cobra venom, LTNF, and LT-10. In a second series of experiments, venom-injected mice were sacrificed after 3, 7, and 10 days and organs assayed for ADA, histamine, and IgE levels. The recovery period to homeostasis for ADA, histamine, and IgE was 7 to 10 days.

Envenoming by Chinese krait ( Bungarus multicinctus) and banded krait ( B. fasciatus) in Myanmar

A retrospective study of 8 cases of envenoming by Chinese krait ( Bungarus multicinctus) and one banded krait ( B. fasciatus) in southern Myanmar is reported. Chinese krait bite produced minimal local reactions, except in one person bitten on the lip which resulted in local swelling. Onset of neurotoxic symptoms occurred 2·5–6 h after the bite, and the interval between bite and death ranged from 12–30 h.Three deaths were due to respiratory failure. Four mildly envenomed cases recovered spontaneously without assisted ventilation. One severely envenomed patient recovered after 8 d intensive respiratory care. Cobra ( Naja kaouthia) antivenom had no value in reversing neurotoxic symptoms. Anticholinesterase injection given to one patient failed to improve neurotoxic symptoms. The bite of banded krait ( B. fasciatus) resulted in neurotoxic envenoming within 2 h after the bite, with minimal local reactions. The victim died of respiratory failure 14 h after the bite.

1820 Ultrastructure of the LTTD of the HABU, trimeresurus flavoviridis

King cobra (Ophiophagus hannah) serum was found to possess antihemorrhagic activity against king cobra hemorrhagin. The activity was stronger than that in commercial king cobra antivenom. An antihemorrhagin has been purified by ion exchange chromatography, affinity chromatography and gel filtration with a 22-fold purification and an overall yield of 12% of the total antihemorrhagic activity contained in crude serum. The purified antihemorrhagin was homogeneous in disc-PAGE and SDS–PAGE. Its apparent molecular weight determined by SDS–PAGE was 120 kDa. The antihemorrhagin was also active against other hemorrhagic snake venoms obtained in Thailand and Japan such as Calloselasma rhodostoma, Trimeresurus albolabris, Trimeresurus macrops and Trimeresurus flavoviridis (Japanese Habu). It inhibited the proteolytic activity of king cobra venom. It is an acid- and thermolabile protein and does not form precipitin lines against king cobra venom.

A peptide from Schumanniophyton magnificum with anti-cobra venom activity.

Using the chick biventer cervicis preparation as a bioassay for antivenom activity, a peptide has been isolated from the aqueous extract of the bark of Schumanniophyton magnificum. The peptide was isolated and purified by a combination of reverse-phase and exclusion column chromatography, preparative TLC, and HPLC. The peptide has a relative molecular mass of about 6000 daltons and is similar in amino acid composition to the cardiotoxins present in snake venom. The isolated peptide showed dose-related inhibitions of the effects of cardiotoxin and total venom of cobra species using the chick biventer cervicis preparation.

Isolation and characterization of the third complement component of axolotl (Ambystoma mexicanum)

1. Using a monoclonal anti-human C3 antibody and a polyclonal anti-cobra venom factor antibody as probes, a protein homologous to the mammalian third complement component (C3) was purified from axolotl plasma and found to be axolotl C3. 2. Axolotl C3 consists of two polypeptide chains (Mr = 110,000 and 73,000) linked by disulfide bonds. An internal thiolester bond in the alpha chain was identified by the incorporation of [14C]methylamine and NH2-terminal sequence from the C3d fragment of C3. 3. Digestion of C3 by trypsin resulted in the cleavage of both the alpha and beta chains, generating fragments with a cleavage pattern similar to that of human C3. 4. The amino acid composition of axolotl C3 and the amino acid sequences of the thiolester site (and the surrounding amino acids), the cleavage site for the C3-convertase, and one of the factor I cleavage sites are similar to C3 from other vertebrates. 5. In contrast to human C3, which has concanavalin A binding carbohydrates on both the alpha and beta chains, only the beta chain of axolotl C3 contains such carbohydrates.

Comparison of Tensilon ® and antivenom for the treatment of cobra-bite paralysis

We prospectively compared the ability of antivenom and edrophonium (Tensilon ®) to improve paralytic symptoms in 8 patients envenomed by the Philippine cobra ( Naja naja philippinensis). Twenty, 50 or 100 ml of Philippine cobra antivenom were administered in a double-blind fashion by constant intravenous infusion over 30 min. Even the largest dose of antivenom failed to produce marked improvement within 2 h, though enzyme-linked immunosorbent assays and neutralization tests demonstrated that it possessed high titres of anti-neurotoxin antibodies. Tensilon ® given at 2 h was significantly more effective than antivenom at increasing the duration of upward gaze (78±28 vs 43±26 sec, P<0·001), and either completely reversed or markedly decreased paralysis in every patient. The Tensilon ® test should be given to all patients with paralytic envenoming by cobras, and anticholinesterases administered to those with a positive response.

A king cobra bite in New York City

A 30-year-old male was bitten on the thumb by a king cobra, Ophiophagus hannah. Transported by helicopter to a snakebite center within 1 hr, he was treated with specific antivenom. He improved, then worsened; the course was finally reversed by huge doses of antivenom (Thai King Cobra Antivenom). The patient recovered without sequelae. The case illustrates the efficacy of an emergency medical system and i.v. administration of specific antivenom in sufficient amounts.