Anti-snake Venom Serum Research Articles

A new in-vitro agglutination technique for potency estimation of antisnake venom serum (ASVS)

Traditionally the potency of ASVS is assayed quantitatively by in-vivo neutralization test for lethality in mice. A sensitive and simple in-vitro agglutination assay for the quantitative determination of Antisnake Venom Serum (ASVS) potency is reported. The method is rapid, cheap, simple, economical and above all does not require the use of experimental animals for potency assay of in process, unpurified and purified sera batches. Among in-vitro procedures, agglutination assay was favored in comparison to flocculation as the later was found to give variable results and also time consuming (high Kf value). Before application, the method was standardized and validated for choice and concentration of particulate material (latex vs. bentonite), temperature and optimum antiserum concentration. It is well known fact that venoms lose toxicity on dilution however this study demonstrated that the bentonite adsorbed venoms of the entire four snake species viz., Cobra, Krait, Russell's viper and Echis are stable even up to 30 days of storage. Among five lots each of unpurified serum, unprocessed plasma and purified sera tested, the results were found comparable with universally accepted in-vivo biological assay. The coefficient of correlation was found to be near 1.0 within 95% fiducial limits of acceptance and also significantly less variation was observed in the mean potency values and standard deviations. For all results p value was observed to be <0.01. Results indicate that in-vitro agglutination assay is suitable and can be used for potency estimation of in process as well as unpurified and purified ASVS batches.

IMPACT OF SNAKE BITES AND DETERMINANTS OF FATAL OUTCOMES IN SOUTHEASTERN NEPAL

Current available data on snake bites in Nepal are based solely on hospital statistics. This community-based study aimed at evaluating the impact of snake bites and determining the risk factors associated with a fatal outcome in southeastern Nepal. A total of 1,817 households, selected by a random proportionate sampling method, were visited by trained field workers in five villages. Extensive data from snake bite victims during the 14 previous months were recorded and analyzed. One hundred forty-three snake bites including 75 bites with signs of envenoming were reported (annual incidence = 1,162/100,000 and 604/100,000, respectively), resulting in 20 deaths (annual mortality rate = 162/100,000). Characteristics of krait bites such as bites occurring inside the house, while resting, and between midnight and 6:00 am were all factors associated with an increased risk of death, as were an initial consultation with a traditional healer, a long delay before transport, and a lack of available transport. An initial transfer to a specialized treatment center and transport by motorcycle were strong protective factors. Among the 123 survivors, wounds required dressing and surgery in 30 (24%) and 10 (8%) victims, respectively, the mean working incapacity period was 15 days, and the mean out-of-pocket expense was 69 U.S. dollars. Snake bite is a major but neglected public health problem in southeastern Nepal. Public health interventions should focus on improving victims' rapid access to anti-snake venom serum by promoting immediate and fast transport to adequate treatment centers, particularly for bites occurring at night.

EXTRACTIVE FRACTIONATION OF EQUINE HYPERIMMUNE PLASMA

Aqueous two-phase partition and triphasic systems containing thiophilic and metal ligands were used to produce anti–snake venom serum using the fractionation of hyperimmune equine plasma with neutralizing activity against Bothrops spp. venom as the model. In poly(ethyleneglycol)(PEG)/salt systems, PEG molecular weight, system pH, and the amount of polyvinylpirrolidone (PVP) added were optimized in order to promote selective immunoglobulin recovery. From these studies a PEG 1500/ammonium sulfate system, pH 8.0, a tie-line length parameter (TLL) 21%, and a 2% PVP K-12 were preliminarily selected. The immunoreactive fraction (ELISA) mainly preferred the top phase, with a theoretical yield of >97% and a purification factor of 3.5. Practical recoveries were, however, hampered by limited product solubility and an erratic global process performance. In order to overcome these limitations, we moved to a system formed by derivatives of cellulose and starch, which contained an affinity solid phase. This three-phase system was compatible with the use of thiophilic or immobilized metal ion affinity (IMAC) supports, the first showing the higher selectivity. The system composed of 2% Methocel, 2% Reppal, 1.0 mol/kg ammonium sulfate, and 5–10% 2S-thioether sulfone agarose allowed recovery of 52% of the immunoreactive fraction from hyperimmune equine plasma at a total protein concentration of 0.25%. This process strategy also allowed simple operation and easy of affinity ligand recycling.

Isolation of IgG T from hyperimmune horse anti-snake venom serum: Its protective ability

Hyperimmune horse anti-bothropic serum, used in serum therapy, was analyzed for its IgG T content and protective ability. IgG T was isolated through a combination of salt-mediated hydrophobic chromatography and protein A affinity chromatography. The chromatographic fractions obtained were analyzed with regard to their isotype content and protective ability. The results suggest that the protective ability of hyperimmune antivenom serum is located mainly in the IgG T subclass.

The effect of Naja nigricollis venom on blood clotting

Naja nigricollis venom has an in vivo anticoagulant action which is heat-labile and is prevented by protamine and polyvalent horse anti-snake venom serum containing no specific antivenin against this venom. This anticoagulant action may be attributed partly to an anti-thromboplastin-like action and partly to heparin release. This venom has also a weak in vitro coagulant action which is masked in vivo by the stronger anticoagulant effect.

Anti-asthmatic effects of immunization with cobra venom

Summary Thirty patients with perennial asthma who had previously benefited from passively conferred immunity by anti-snake venom serum were actively immunized with cobra venom. Results obtained with anti-snake venom serum were reproduced with cobra venom. Improvement with cobra venom was first noticed in all patients after two to five months' therapy. Eighteen patients were completely relieved in four to nine months. The remaining 12 patients were partially relieved, to the same extent as with anti-snake venom serum, in two to seven months. During 18 to 38 months of subsequent treatment, four out of these partially relieved 12 patients showed further improvement. Treatment with cobra venom was free from unwanted effects. The role of phosphatidase A in releasing histamine is discussed. The beneficial effect of cobra venom is ascribed to its phosphatidase A and hyaluronidase contents, which are antigenic and result in increased anti-phosphatidase A, anti-invasin 1, and anti-histamine activity in the asthmatic patient. The treatment is worth further investigation as an alternative or as an addition to bronchodilators or cortisone when a reduction in dosage is desired.

The Relative Efficiency of Two Types of Anti-Venom Sera in Neutralizing Cobra Venom

DURING the summer of 1945 I was stationed Manila, P.I., with one of the United States Army Medical General Laboratories.1 During the course of the summer two snake antivenins were received at the laboratory for testing against the venom of the Luzon cobra, Naja naja philippinensis. According to Taylor ..... These snakes are poisonous, and probably cause more deaths than any other snake the Philippines. The subspecies is found very commonly Luzon, ... . Up to the time of the study two deaths from cobra bite had already been reported among U.S. military personnel stationed or near Manila and an efficient antivenin was being sought for use by the military forces. The two antivenins to be tested differed mainly the fact that one was a locally prepared (Institute of Hygiene, University of the Philippines) antivenin, specific for the venom of the Philippine cobra. This antivenin was prepared June, 1941, and packaged a 10.0 cubic centimeter hermetically sealed vial. It had an expiration date of June, 1942. The was prepared from horses hyperimmunized against the venom of N. n. philippinensis. The fact that this serum's expiration date was 1942 left its efficacy open to question, since liquid is considered unstable if stored at temperatures above 4? C. (39? F.). The other antivenin received was an Indian polyvalent Anti-snake venom serum prepared from horses hyperimmunized against four snakes: Russell's viper, Vipera russellii; the saw-scaled viper, Echis carinatus; the common krait, Bungarus caeruleus; an Indian cobra, Naja naja (subsp.?). This was desiccated, lyophilized, and packaged with sufficient sterile, distilled water, included a separate vial, to yield 10.0 cc. of reconstituted serum. Date of manufacture was July, 1945. The was prepared by the Haffkine Institute, Bombay, India. Both types of antivenin had been successfully used, but it was desired to check their relative efficiency against cobra venom, under controlled conditions. Since there was only a small quantity of each type of available for testing purposes, it was decided to use white mice for laboratory animals and to run the experiment in reverse, so to speak, order to obtain the most information from a given lot of antivenin. This will be explained more detail later.