Merit and Demerit of Polyvalent Snake Antivenoms

©2002 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016

Journal of Toxicology

TOXIN REVIEWS

Vol. 22, No. 1, pp. 77–89, 2003

Merit and Demerit of Polyvalent Snake Antivenoms

Kavi Ratanabanangkoon*

Department of Microbiology, Faculty of Science, Mahidol University,

Bangkok, Thailand

ABSTRACT

Polyvalent antivenoms contain specific antibodies capable of neutraliz-

ing a number of homologous venoms from different species/genera.

They can save lives of victims of snake envenomations, even when the

culprit snake has not been identified (the usual case, about 80% of the

time), and a monovalent antivenom can not be chosen. They are useful in

areas where there are too many poisonous species to produce monovalent

antivenoms against all of them. It is now possible to prepare polyvalent

antivenoms with high potencies comparable to those of the correspond-

ing monovalent antivenoms. With good manufacturing processes, these

antivenoms have been shown to cause few and minor adverse reactions.

In addition, polyvalent antivenoms exhibit a wider range of paraspecific

neutralization of venoms from different species/genera, even from

distant geographic areas. Lastly, it is less expensive and easier to pro-

*Correspondence: Kavi Ratanabanangkoon, Ph.D., Department of Microbiology,

Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand;

Fax: 662-644-5411; E-mail: [email protected].

77

DOI: 10.1081/TXR-120019563 0731-3837 (Print); 1525-6057 (Online)

Copyright D 2003 by Marcel Dekker, Inc. www.dekker.com

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duce and handle a few polyvalent antivenoms than batteries of mono-

valent antivenoms.

Key Words: Snake antivenom; Polyvalent; Monovalent.

INTRODUCTION

Therapeutic antivenom was first produced by A. Calmette in 1894. It

was prepared against Naja kaouthia venom. Later in 1911 Vital Brazil

produced the first polyvalent antivenom (pAV) against several snakes

(Boquet, 1979). This antivenom, also termed polyspecific antivenom,

should be differentiated from antivenoms prepared by mixing various mo-

novalent antivenoms (mAV) which amounts to diluting the specific anti-

body within each monovalent antivenom (Christensen, 1979).

The need to produce pAV stems from the facts that numerous poisonous

snakes may co-inhabit the same locality and that, in the majority of cases of

snake envenomation, the culprit snakes are not identified. pAV produced

against these snakes can therefore guard against treatment failure due to

administration of an incorrect mAV. Although the benefit of pAV in

this respect is quite obvious, there are still questions about the effectiveness of

and the adverse reactions produced by pAVs as compared to those of mAVs.

This article is intended to compare various characteristics of mono-

valent and polyvalent antivenoms with regard to their potency, adverse

reactions, paraspecificity and production processes.

ANTIVENOM PRODUCTION

Almost all commercial therapeutic mAVs and pAVs are produced in

horse, although goat (Mohamed et al., 1966) and sheep (Karlson-Stiber

et al., 1997; Meyer et al., 1997; Sells et al., 1994) have also been used. AVs

are prepared depending on the frequency of the bites by various snakes, the

severity and the availability of venoms in the locality. Up to 10 different

venoms have been used in immunization for the production of a pAV

(Weinstein et al., 1991).

Production Processes

Almost all the processes involved in antivenom production ie., im-

munization of horses and fractionation of sera, whether of mAV or pAV,

are similar. Thus, the animal, the immunization schedule, the adjuvant and

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bleeding usually follow almost the same protocols. The major difference is

the composition of immunogen: one venom is used as immunogen in mAV

production while several venoms are used in pAV production.

The fractionations of sera usually involve enzyme digestion (pepsin to

produce F(ab’)2 or papain to produce Fab) and fractional precipitation by

ammonium sulfate (Christensen, 1979), while others use caprylic acid (dos

Santos et al., 1989; Rojas et al., 1994). Furthermore, some manufacturers

include affinity chromatography to isolate only the specific antibody against

toxins/venoms (Kukongviriyapan et al., 1982; Smith et al., 1992). These

fractionation processes result in different degrees of purity, which affect the

potency and the incidence of adverse reactions of the product.

The Amount of Venom Used in the Immunization

The amount of venoms used in immunization is an important de-

terminant in antivenom production (Chippaux and Goyffon, 1998). An AV

may not be produced simply because of insufficient supply of a venom

needed for a course of immunization. The total amount of each venom used

in the production of pAV has been shown to be less than or comparable to

that for mAV. For example, Christensen used about 150 mg and 75 mg of

each venom for mAV and pAV productions, respectively (Christensen,

1979). With a novel immunization protocol (Pratanaphon et al., 1997) the

amounts of each venom used for mAV and pAV productions are com-

parable (Chotwiwatthanakun et al., 2001).

Biological Variations in mAV and pAV Productions

In the immunization of horses, as with other outbred animals, a high

degree of biological variation is usually observed. Depending on the ad-

juvant used, some horses immunized with a snake venom may not respond

or may fail to yield a high enough antibody titer (Pratanaphon et al., 1997).

For mAV production, these non-responders can either be discarded or used

in immunization with other more immunogenic venoms. A more difficult

situation is sometimes encountered in pAV production. Among various

venoms used to immunize a horse, the horse may respond well toward some

but not all the venoms. Thus, the antivenom may not be as ‘polyvalent’ as

intended. Christensen solved this problem by immunizing a number of

horses and pooling all the sera (Christensen, 1979). This way the antibody

titers against each venom seemed to average out, and usually the resulting

sera contained all the neutralizing activities to make it fully polyvalent.

Another approach is to monitor the antibody response of each horse against

each venom used in the immunization. Any horse that fails to respond to a

Polyvalent Snake Antivenoms 79

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venom can then be given booster injections with that particular venom to

raise the antibody titer (Chotwiwatthanakun et al., 2001).

Facility and Cost of AV Production and Handling

There are several important aspects in AV production which may favor

the choice of AV (monovalent or polyvalent). In the production of mAVs,

several venoms and groups of horses have to be prepared and immunized. In

pAV production, there are fewer groups of horses and fewer venom mixtures,

and the chance of mismatch is less. During fractionation, it is easier and

cheaper to process a big batch of pAV than several small batches of mAVs.

The cost of AV production depends a great deal on the administrative

expenses, the maintenance of horses, wages, ampouling and packaging of

the final products. When all these expenses are taken into consideration, it

is cheaper to produce a pAV than several mAVs. Moreover AVs are

frequently used in rural areas in developing countries where healthcare

facilities may not be optimal. It is easier for personnel to handle, store and

keep an inventory of 1 or 2 pAVs instead of several mAVs. It is also easier

for physicians to carry around one pAV rather than many different mAVs.

MERIT AND DEMERIT OF pAV ASCOMPARED TO mAV

From the above discussion, it is evident that pAVs can be produced as

efficiently as mAVs and in some respects, pAVs are easier and cheaper to

produce. However, there are other important aspects that need to be

considered when comparing mAV and pAV.

The Need to Produce Polyvalent Antivenoms

Snake Envenomation and Snake Identification

Antivenoms against snakes are in general specific for the venom which

was used in the immunization. Cross-reactions of AV with heterologous

venom proteins, as demonstrated by immunoprecipitation or Western blot

analysis, are frequently observed, thus indicating antigenic relatedness

(Chinonavanig et al., 1988). However, cross-neutralization is not gen-

erally encountered (Ganthavorn, 1969). Thus, in the treatment of snake

envenomation, species diagnosis of the culprit snake is essential so that the

appropriate mAV can be administered. Furthermore, without the culprit

snake, species diagnosis based only on the signs and symptoms of the

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victim is very difficult, if not impossible. Because snake envenomations

usually take place in bushy areas or in the dark, it is not surprising that in

the majority of cases, the snakes are not identified. For example in

Thailand, the culprit snakes were identified in only about 20% of poisonous

snakebites (Songsumard, 1995). Coetzer and Tilburg reported only 30–40%

of envenomations in which the culprit snakes were identified (Coetzer and

Tilburg, 1982). Since administration of a wrong mAV can lead to treatment

failure and even death, a pAV, which can neutralize all the relevant venoms

in the locality can be extremely useful in saving life.

The need to accurately identify the culprit snake so that appropriate AV

can be administered has let to the development of various rapid diagnostic

kits for venom identification (Coulter et al., 1980; Kittigul and Rata-

nabanangkoon, 1993). However, only in Australia are snake identification

test kits often used to aid physicians in AV treatment (White, 1998). Even

here, about 30% of snake envenomations were treated with pAVs either

because the test kit was not used, gave inconclusive results, or because the

condition of the victim was too severe to wait for test results. Furthermore,

when numerous species of poisonous snakes inhabit the same area, the use

of diagnostic kits or clinical signs and symptoms for species identification

usually fails to give conclusive results (Tan et al., 1994). Under these

circumstances, a pAV can be very useful and avoid the need for a diag-

nostic kit, which can further delay AV administration and add to the cost

of treatment.

The Number of Poisonous Snakes in the Area

In some tropical countries, a large number of poisonous snakes share

a common habitat. For example, in Malaysia, up to 10 species of

Trimeresurus are found, many of them medically important (Tan et al.,

1994). In many South American countries, numerous poisonous snakes of

different genera and species are responsible for human morbidity and

mortality. It is not possible nor practical to prepare several different mAVs

for use. It would be much easier to have only one or two pAV’s, which can

effectively neutralize all the venoms in the area.

From the above discussions, it is clear that pAVs have an essential role

in the treatment of snake envenomation and could save lives under circum-

stances where mAVs could lead to treatment failure and even death. How-

ever, there are still some doubts among certain medical professionals on the

effectiveness and the adverse reactions of pAV as compared to mAVs.

It should be mentioned that there is still some misconception that

mAVs are specific while pAVs are non-specific against homologous

venoms, and therefore that pAVs are less effective. In fact, pAVs contain


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specific antibodies against the venoms used in immunization and therefore

neutralization of these homologous antigens should be highly specific and

effective and to the same degree observed with mAV. Again, it must be

reiterated that polyvalent AVs are those produced by immunizing a horse

with several venoms and not by mixing several monovalent AVs. The

drawbacks of such a mixture are that it is wasteful in terms of mAVs and

that the patient will receive significantly more equine (or foreign) proteins

in each treatment.

In order to compare various properties of mAV and pAV, it is

necessary that these AVs are in the same stage of purity and, if possible,

produced by the same manufacturers. The following examples emphasize

this point. Theakston et al. (1995) studied 5 pAVs and 1 mAV prepared by

different manufacturers and found vast differences in their neutralizing

potencies against venoms of Bothrops species and Lachesis muta. Similar

observations were made on 4 pAV’s anti-Bothrops prepared by different

manufacturers from 4 countries (Bogarin et al., 1995).

Antivenom Potency

One of the reasons often cited as a drawback of pAVs is the believe

that pAVs are less potent against homologous venoms than the cor-

responding mAVs. This belief most likely stems from the observation that

the horses are immunized with a greater number of venom proteins in the

preparation of pAV, as compared to that in mAV preparation. Thus, by

‘antigenic competition’ the antibody response of the horse towards each

venom protein is thought to be less in the pAVs (Pross and Eidinger, 1974).

However, ‘antigenic competition’ is a rare phenomenon and does not seem

to be a problem in AV production (Boquet, 1979). In an experiment using

the a toxin of N. nigricollis, Boquet showed that antigenic competition was

not present (Boquet, 1979). We have found that the ED50s of a pAV

against homologous venoms are comparable to the ED50s of mAVs

prepared by the low-dose, low-volume multi-site immunization protocol

(Chotwiwatthanakun et al., 2001). In fact the ED50 of pAV against some

homologous venoms are even lower than that of mAVs. Christensen

contended that the presence of various venom proteins might in fact act

as an ‘adjuvant’ to enhance the antibody response of others (Christensen,

1979). Similar conclusions were reached by Chippaux and Goyffon (1991)

and Sunthornandh et al. (1992).

Otero et al. compared one mAV and 5 pAVs in neutralizing he-

morrhage, edema and myotoxicity of Bothrops atrox venom (Otero et al.,

1996). When an anti-bothropic mAV and a pAV were prepared from the

same manufacturer ie., INS of Columbia, it was found that the pAV was

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more potent than the mAV. Furthermore, Otero et al. conducted a ran-

domized double blind clinical trial of a mAV and a pAV prepared from the

same manufacturer in Costa Rica (Otero et al., 1995). An mAV anti-B.

atrox is compared to a pAV anti-Crotalinae prepared against B. asper,

Crotalus durissus durissus and Lachesis muta stenophrys. It was found that

these 2 antivenoms are equally effective in neutralizing hemorrhagic and

clotting defect and in removing venom antigens from circulation. No sig-

nificant difference in incidents of adverse reactions was observed.

Similar findings by various groups of investigators have led to the

conclusion that pAVs can be prepared to be as potent as mAVs.

Adverse Reactions

Adverse reactions caused by antivenom are related to the quantity and

quality of the animal (equine) proteins administered (Malasit et al., 1986).

AVs against the same groups of snakes, prepared by different manufac-

turers, can differ markedly not only in their neutralizing capacities but also

in purity including the presence or absence of insoluble materials. These

properties inevitably affect the incidence of adverse reactions caused by

the AVs.

Is the immunoglobulin content in pAV higher than that in mAV? By

subjecting mAV and pAV sera to SDS-polyacrylamide gel electrophoresis,

the immunoglobulin bands can be separated and quantitated by scanning the

gels. It was found that the immunoglobulin bands which contain all venom

neutralizing activity, were 37–38% of the total serum protein. There was no

significant difference between the immunoglobulin content in the sera

of mAV and pAV (unpublished observations). This, together with the

observation that pAV can be prepared with the same potency as that of

mAVs (previous section) suggests that the amount of equine protein, whe-

ther of mAV or pAV, received by the patient should be similar and the

incidence of adverse reactions should be comparable.

Chippaux et al. studied 223 patients in Cameroon receiving 4–5 vials

of pAV per patient (Chippaux et al., 1998). The adverse reactions of the

pAV produced against 9 snake venoms by IPSER Africa showed less than

1% of patients suffered from anaphylactic shock and serum sickness. Early

adverse reaction of varying degrees of severity was found in 6.3%. Fur-

thermore, Chippaux et al. conducted a clinical trial of a pAV produced by

Pasteur–Merrieux–Connaught in Cameroon (Chippaux et al., 1999). Of 46

patients treated, all were clinically cured and no patient suffered from

serum sickness. Offerman et al. studied the incidence and severity of acute

side effects from the use of pAVs in treating rattlesnake bites (Offerman

et al., 2001). Of 65 patients receiving pAV, 18% showed adverse re-


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actions—solely urticaria. They concluded that the pAV is safe, and serious

side effects are uncommon. On the contrary, Moran et al. found the in-

cidence of adverse reactions of a pAV prepared in South Africa to be high

(Minton, 1979). They observed that 76% of the patients showed early se-

vere reaction (anaphylactoid reactions).

From these few examples, it is clear that the production processes which

determine the potency and purity of the AV, and not the valency of the AV,

are contributing factors of adverse reactions. With good manufacturing pro-

cesses, it is certain that pAV and mAV can be produced so that the incidence

of adverse reactions caused by them is low, mild and comparable.

Paraspecificity

Antivenoms are by design able to neutralize those homologous venoms

used in the immunization of horses. Because of the specificity of the

immunological response, most mAVs are highly specific against homolog-

ous antigens, and cross-neutralization is not usually observed (Ganthavorn,

1969). However, cross-reactions and in some case cross-neutralization by

antivenom of heterologous venoms of the same or even different genera

have occasionally been observed, indicating the similarity in antigenic

structures of these venom proteins. This ‘paraspecificity’ of antivenoms has

been quite useful in the treatment of envenomation by a snake against which

no homologous antivenom is available (Moran et al., 1998). Thus, Weinstein

et al. tested a pAV prepared against 10 snake venoms and found to ex-

tensively cross-react with heterologous venoms (Weinstein et al., 1991).

Similar observations were reported by Chippaux et al. (1998).

Paraspecific neutralization of heterologous venoms is usually less

effective than that observed with homologous venoms. Braz et al. showed

that a pAV prepared against venoms of two scorpions and two spiders

exhibited cross-neutralization of a heterologous venom of Loxosceles inter-

media, a Brazilian spider (Braz et al., 1999). However, this paraspecific

neutralization is less effective than that observed with a homologous mAV.

What is more interesting is that some antivenoms contained heteroclitic

antibodies which neutralize heterologous venoms with higher potency

than that observed with homologous venoms. Thus, Gutierrez et al., showed

that a pAV prepared against Bothrops asper, Lachesis muta and Crota-

lus durissus durissus not only effectively neutralized the proteolytic and

hemorrhagic activities of homologous venoms, but also that of B. schlegelii

venom (Gutierrez et al., 1985). This paraspecific activity of the pAV was

even more effective than that observed with B. asper. Similarly, Tan et al.,

studied a pAV against various Trimeresurus species (Tan et al., 1994). This

pAV showed paraspecific neutralization of hemorrhagic, narcotizing and

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thrombin-like activities of various heterologous venoms even better than

that with homologous venoms. Two monovalent antivenoms used in their

study exhibited much less paraspecificity.

It should be noted that pAVs which are normally prepared against a

wide range of venom antigens usually exhibit a greater degree of para-

specificity than that observed with mAVs. Thus, Mebs tested a commercial

pAV produced against cobras (N. haje, N. nigricollis and N. nivea) (Mebs,

1986). This AV effectively neutralized the myotoxic phospholipase A2 of

the cobra venoms but also cross-neutralized the effect of T. flavoviridis

venom. In contrast, mAV against T. flavoviridis did not cross-neutralize

the activity of the cobra venoms. Kornalik and Taborska reported that 2

pAVs showed extensive cross-reaction and complete cross-neutralization

with heterologous venoms while less cross-reaction was observed in a mAV

(Kornalik and Taborska, 1989). Furthermore, Mebs et al. showed that pAV

prepared against African viperid and elapid snake venoms can cross-

neutralize hemorrhagic activity of heterologous venoms even of different

genera from distant geographic areas (America and Asia) (Mebs et al., 1988).

Because of the paraspecific activity, careful selection of antigens

among various venoms will enable preparation of AVs with wide cross-

neutralizing activities (Gingrich and Hohenadel, 1956). In this respect,

pAVs which usually exhibit extensive paraspecific neutralization of hete-

rologous venoms are very useful and can save lives when specific mAVs

are not available.

CONCLUDING REMARKS

The life-saving role of pAV in the treatment of envenomation by

unidentified snakes has long been recognized. There is now evidence to show

that pAV with neutralizing potency comparable to that of mAV can readily

be prepared. When produced by the same manufacturers, no significant dif-

ference in the adverse reactions caused by pAV and mAV has been observed.

The higher paraspecific neutralization and ease of production and handling

of pAVs are advantages, when compared to mAVs. Thus, production and

use of potent and well fractionated pAVs should be encouraged.

ABBREVIATIONS

ED50 effective dose 50, expressed as ml of serum per mg venom

mAV monovalent antivenom

pAV polyvalent antivenom


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ACKNOWLEDGMENTS

The research carried out on antivenoms was funded by a grant from the

National Science and Technology Development Agency of Thailand. The

author thanks Prof. Maurice Broughton for valuable suggestions.

REFERENCES

Bogarin, G., Segura, E., Duran, G., Lomonte, B., Rojas, G., Gutierrez, J. M.

(1995). Evaluation of neutralizing ability of four commercially

available antivenoms against the venom of Bothrops asper from Costa

Rica. Toxicon 33:1242–1247.

Boquet, P. (1979). Immunological properties of snake venoms. In: Lee, C. Y.,

ed. Snake Venoms. Berlin: Springer, pp. 751–824.

Braz, A., Minozzo, J., Abreu, J. C., Gubert, I. C., Chavez-Olortegui, C.

(1999). Development and evaluation of the neutralizing capacity of

horse antivenom against the Brazilian spider Loxosceles intermedia.

Toxicon 37:1323–1328.

Chinonavanig, L., Billings, P. B., Matangkasombut, P., Ratanabanangkoon,

K. (1988). Antigenic relationships and relative immunogenicities of

venom proteins of six poisonous snakes of Thailand. Toxicon 26:883–

890.

Chippaux, J. P., Goyffon, M. (1991). Production and use of snake antivenin.

In: Tu, A. T., ed. Handbook of Natural Toxins. Vol. 5. New York:

Marcel Dekker, pp. 529–555.

Chippaux, J. P., Goyffon, M. (1998). Venoms, antivenoms and immunother-

apy. Toxicon 36:823–846.

Chippaux, J. P., Lang, J., Eddine, S. A., Fagot, P., Rage, V., Peyrieux, J. C.,

Le Mener, V. (1998). Clinical safety of a polyvalent F(ab’)2 equine

antivenom in 223 African snake envenomations: a field trial in

Cameroon. VAO (Venin Afrique de l’Ouest) Investigators. Trans. R.

Soc. Trop. Med. Hyg. 92:657–662.

Chippaux, J. P., Lang, J., Amadi-Eddine, S., Fagot, P., Le Mener, V. (1999).

Short report: treatment of snake envenomations by a new polyvalent

antivenom composed of highly purified F(ab)2: results of a clinical trial

in northern Cameroon. Am. J. Trop. Med. Hyg. 61:1017–1018.

Chotwiwatthanakun, C., Pratanaphon, R., Akesowan, S., Sriprapat, S.,

Ratanabanangkoon, K. (2001). Production of potent polyvalent anti-

venom against three elapid venoms using a low dose, low volume,

multi-site immunization protocol. Toxicon 39:1487–1494.

86 Ratanabanangkoon

Tox

in R

evie

ws

Dow

nloa

ded

from

info

rmah

ealth

care

.com

by

Uni

vers

itat d

e G

iron

a on

11/

18/1

4Fo

r pe

rson

al u

se o

nly.



Christensen, P. A. (1979). Production and standardization of antivenin. In:

Lee, C. Y., ed. Snake Venoms. Berlin: Springer, pp. 825–846.

Coetzer, P. W. W., Tilburg, C. R. (1982). The epidemiology of snakebite in

northern Natal. S. Afr. Med. J. 62:206–212.

Coulter, A. R., Harris, R. D., Sutherland, S. K. (1980). Enzyme immunoassay

for the rapid clinical identification of snake venom. Med. J. Aust.

1:433–435.

dos Santos, M. C., D’Imperio, M. R., Furtodo, G. C., Colletto, G. M. D. D.,

Kipnis, T. L., Dias da Silva, W. (1989). Purification of F(ab’)2 anti-

snake venom by caprylic acid: a fast method for obtaining IgG frag-

ments with high neutralization activity, purity and yield. Toxicon

27:297–303.

Ganthavorn, S. (1969). Toxicities of Thailand snake venoms and neutraliza-

tion capacity of antivenin. Toxicon 7:239–241.

Gingrich, W. C., Hohenadel, J. C. (1956). Standardization of polyvalent

antivenins. Venoms. Washington, DC: A.A.A.S.

Gutierrez, J. M., Gene, J. A., Rojas, G., Cerdas, L. (1985). Neutralization of

proteolytic and hemorrhagic activities of Costa Rican snake venoms by

a polyvalent antivenom. Toxicon 23:887–893.

Karlson-Stiber, C., Persson, H., Heath, A., Smith, D., Al-Abdulla, I. H.,

SyOstrom, L. (1997). First clinical experiences with specific sheep Fab

fragments in snake bite. Report of a multicenter study of Vipera berus

envenoming. J. Int. Med. 241:53–58.

Kittigul, L., Ratanabanangkoon, K. (1993). Reverse passive hemagglutina-

tion tests for rapid diagnosis of snake venoms. J. Immunoassay. 14:

105–127.

Kornalik, F., Taborska, E. (1989). Cross reactivity of mono- and polyvalent

antivenoms with Viperidae and Crotalidae snake venoms. Toxicon

27:1135–1142.

Kukongviriyapan, V., Poopyruchpong, N., Ratanabanangkoon, K. (1982).

Some parameters of affinity chromatography in the purification of

antibody against Naja naja siamensis Toxin 3. J. Immunol. Methods

49:97–104.

Malasit, P., Warrell, D. A., Chanthavanich, P., Viravan, C., Mongkolsapaya,

J., Singhthong, B., Supich, C. (1986). Prediction, prevention and me-

chanism of early (anaphylactic) antivenom reactions in victims of

snake bites. Br. Med. J. 292:17–20.

Mebs, D. (1986). Myotoxic activity of phospholipases A2 isolated from cobra

venoms: neutralization by polyvalent antivenoms. Toxicon 24:1001–

1008.

Mebs, D., Pohlmann, S., Von Tenspolde, W. (1988). Snake venom hemor-


Tox

in R

evie

ws

Dow

nloa

ded

from

info

rmah

ealth

care

.com

by

Uni

vers

itat d

e G

iron

a on

11/

18/1

4Fo

r pe

rson

al u

se o

nly.



rhagins: neutralization by commercial antivenoms. Toxicon 26:453–

458.

Meyer, W. P., Habib, A. G., Onayade, A. A., Yakubu, A., Smith, D. C.,

Nasidi, A., Daudu, I. J., Warrell, D. A., Theakston, R. D. G. (1997).

First clinical experiences with a new Fab Echis ocellatus snake bite

antivenom in Nigeria: randomized comparative trial with Institute

Pasteur Serum (IPSER) Africa antivenom. Am. J. Trop. Med. Hyg.

56:291–300.

Minton, S. A. Jr. (1979). Common antigens in snake venoms. In: Lee, C. Y.,

ed. Snake Venoms. Berlin: Springer, pp. 847–862.

Mohamed, A. H., Bakr, I. R., Kamel, A. (1966). Egyptian polyvalent anti-

snake bite serum; technique of preparation. Toxicon 4:69–72.

Moran, N. F., Newman, W. J., Theakston, R. D., Warrell, D. A., Wilkinson,

D. (1998). High incidence of early anaphylactoid reaction to SAIMR

polyvalent snake antivenom. Trans. R. Soc. Trop. Med. Hyg. 92:69 –70.

Offerman, S. R., Smith, T. S., Derlet, R. W. (2001). Does the aggressive use

of polyvalent antivenin for rattlesnake bites result in serious acute side

effects? West. J. Med. 175:88–91.

Otero, R., Nunez, V., Osorio, R. G., Gutierrez, J. M., Giraldo, C. A., Posada,

L. E. (1995). Ability of six Latin American antivenoms to neutralize the

venom of mapana equis (Bothrops atrox) from Antioquia and Choco

(Colombia). Toxicon 33:809–815.

Otero, R., Gutierrez, J. M., Nunez, V., Robles, A., Estrada, R., Segura, E.,

Toro, M. F., Garcia, M. E., Diaz, A., Ramirez, E. C., Gomez, G.,

Castaneda, J., Moreno, M. E. (1996). A randomized double-blind

clinical trial of two antivenoms in patients bitten by Bothrops atrox in

Colombia. The Regional Group on Antivenom Therapy Research

(REGATHER). Trans. R. Soc. Trop. Med. Hyg. 90:696–700.

Pratanaphon, R., Akesowan, S., Khow, O., Sriprapat, S., Ratanabanangkoon,

K. (1997). Production of highly potent horse antivenom against the

Thai cobra (Naja kaouthia). Vaccine 15:1523–1528.

Pross, H. F., Eidinger, D. (1974). Antigenic competition: a review of non-

specific antigen-induced suppression. Adv. Immunol. 18:133–168.

Rojas, G., Jimenez, J. M., Gutierrez, J. M. (1994). Caprylic acid fractionation

of hyperimmune horse plasma: description of a simple procedure for

antivenom production. Toxicon 32:351–363.

Sells, P. G., Jones, R. G., Laing, G. D., Smith, D. C., Theakston, R. D. (1994).

Experimental evaluation of ovine antisera to Thai cobra (Naja

kaouthia) venom and its alpha-neurotoxin. Toxicon 32:1657–1665.

Smith, D. C., Krisana, R. R., Laing, G., Theakston, R. G. D., Landon, J.

(1992). An affinity purified ovine antivenom for the treatment of

Vipera berus envenoming. Toxicon 30:865–871.

88 Ratanabanangkoon

Tox

in R

evie

ws

Dow

nloa

ded

from

info

rmah

ealth

care

.com

by

Uni

vers

itat d

e G

iron

a on

11/

18/1

4Fo

r pe

rson

al u

se o

nly.



Songsumard, S. (1995). Snakebite in Thailand. In: Annual Epidemiology

Surveillance Report, Ministry of Public Health. pp. 324–333.

Sunthornandh, P., Matangkasombut, P., Ratanabanangkoon, K. (1992).

Preparation, characterization and immunogenicity of various polymers

and conjugates of elapid post-synaptic neurotoxins. Mol. Immunol.

29:501–510.

Tan, N. H., Choy, S. K., Chin, K. M., Ponnudurai, G. (1994). Cross-reactivity

of monovalent and polyvalent Trimeresurus antivenoms with venoms

from various species of Trimeresurus (lance-headed pit viper) snake.

Toxicon 32:849–853.

Theakston, R. D., Laing, G. D., Fielding, C. M., Lascano, A. F., Touzet, J.

M., Vallejo, F., Guderian, R. H., Nelson, S. J., Wuster, W., Richards, A.

M. (1995). Treatment of snake bites by Bothrops species and Lachesis

muta in Ecuador: laboratory screening of candidate antivenoms. Trans.

R. Soc. Trop. Med. Hyg. 89:550–554.

Weinstein, S. A., Schmidt, J. J., Smith, L. A. (1991). Protein lethal toxins and

cross-neutralization of venoms from the African water cobras,

Boulengerina annulata annulata and Boulengerina christyi. Toxicon

29:1315–1327.

White, J. (1998). Envenoming and antivenom use in Australia. Toxicon

36:1483–1492.


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Merit and Demerit of Polyvalent Snake Antivenoms