snakebites: physiopathology

SNAKEBITES: PHYSIOPATHOLOGY

BENEDITO BARRAVIERA

Full Professor of Tropical Diseases - Botucatu Medical School - UNESPResearch from The Center for the Study of Venoms and Venomous Animals – CEVAPSão Paulo State University - UNESP - Brazil

CONTENTS

1-The São Paulo State University history;

2-The Center for the Study of Venoms and Venomous Animals – CEVAP – facilities;

3-Main Brazilian venomous and nonvenomous snakes;

4-Classification and Epidemiology;

5-Clinical manifestations and physiopathology;

São Paulo State University campuses

São Paulo State University – UNESP

Based in São Paulo citySupported by São Paulo State Government Annual Budget – U$ 750,000,000 / year (R$ 1.370.788.000,00 - 2008)

UNESP has 23 University Campuses (32 Colleges, 7 Research Centers and 3 Technical schools)

168 Undergraduate courses – 34,425 students108 Graduate courses – 12,031 students3,354 Professors and Researchers6,984 Employees

30 Libraries, 5 Farms, 2 Medical Hospitals, 3 Veterinary Hospitals and1,900 Research and Teaching laboratories

The Center for the Study of Venoms and Venomous

Animals – CEVAP

CEVAP was created in 1993. It is based at Lageado Experimental Farm adjoining Botucatu School of Agronomical Sciences.

It is a Research Institution focusing Toxinology. The multicampus structure of UNESP allows the interaction among Learning, Research, Continuing education and Extension.

The Center for the Study of Venoms and Venomous

Animals – CEVAP

CEVAP count on the following partners: Botucatu Medical School , Botucatu School of Veterinary Medicine and Animal Husbandry, Botucatu and Rio Claro Institute of Biosciences and Araraquara School of Pharmaceutical Sciences.

Total farm area – 2,000 hectares (600 hectares of native forests).

The Center for the Study of Venoms and Venomous Animals - CEVAP

CEVAP Laboratories and Serpentariums

Serpentariums

Extension activities

MAIN BRAZILIAN SNAKES

From Public Health point of view

1-Venomous snakes (about 58 species)

Viperidae family – Bothrops sp (28 species) Crotalus sp (6 sub-species) Lachesis sp (2 species)

Elapidae family – Micrurus sp (22 species)

2-Nonvenomous snakes (about 250 species)

Boidae family - Boa constrictor, Eunectus murinus, Corallus caninus, Epicrates cenchria (11 species)

Colubridae family – Clelia clelia, Liophis frenatus, Philodryas olfersii, Dipsas albifrons, Spilotis pullatus, Waglerophis merremii, Mastigodryas bifossatus, etc. (239 species)

MAIN BRAZILIAN VENOMOUS SNAKES

Viperidae family

– Bothrops sp – Bothrops jararaca, B. alternatus, B. moojeni, B.

atrox (from Amazon region), B. cotiara, B. erytromelas, etc.

-Responsible for 80 to 90% of accidents in Brazil

-Crotalus sp – Crotalus durissus terrificus, C. d. collilineatus, C.

d. marajoensis, C. d. cascavella, C. d. trigonicus, C. d. ruruima

-Responsible for 10 to 20% of accidents in Brazil

-Lachesis sp – Lachesis muta muta, Lachesis muta rhombeata

-Responsible for 3% of accidents in the Amazon region - Brazil.

Bothrops jararaca

Bothrops alternatus

Bothrops moojeni

Bothrops sp distribution

Bothrops moojeni

Crotalus sp distribution

Crotalus durissus terrificus(South American rattlesnake)

Crotalus durissus terrificus

MAIN BRAZILIAN VENOMOUS SNAKES IN AMAZON REGION

MAIN BRAZILIAN VENOMOUS SNAKES IN THE AMAZON REGION

Bothrops atrox *Bothrops braziliBothriopsis bilineataBothriopsis teniata

Lachesis muta muta *

MAIN BRAZILIAN VENOMOUS SNAKES IN THE AMAZON REGION

Lachesis muta muta

Bothriopsis bilineata

Bothrops atrox

Lachesis muta muta

MAIN BRAZILIAN VENOMOUS SNAKES

Elapidae family

-Micrurus sp – Micrurus frontalis, M. corallinus, M. paraensis, M. spixii, M. filiforms, etc.-Responsible for less than 1% of accidents in Brazil

Micrurus corallinus

Micrurus sp distribution

Micrurus frontalis

Boa constrictor

Corallus caninusEunectus murinus

Boidae family

Nonvenomous snakes

Colubridae family Nonvenomous snakes

Spilotes pullatus

Liophis miliaris

Philodryas olfersii

Accidents caused by venomous animals in Brazil

Snakes – 30,000/year

Scorpions – 40,000/year

Spiders – 19,500/year

Bees and wasps – 1,500/year

Catterpilars – 500/year

São Paulo State – 2,000/year

Botucatu – 100/year

EPIDEMIOLOGY

Main seasonSummer – from December to March

Patient´s characteristicsRural workers, Male (74.84%) , 15 to 49 years old, lower limbs (62.75%)

Snakes characteristics87.33% Bothrops sp envenoming7.43% Crotalus sp envenoming1.37% Lachesis sp envenoming0.41% Micrurus sp envenoming

The Amazon region – 3,000 cases/year90% Bothrops sp envenoming10% Lachesis sp and others

EPIDEMIOLOGY

Bothropic envenoming

Clinical aspectsVenom activity – Bothrops sp

1-Coagulative activity – cause bleeding and clotting disturbances

Patient

with

severe

gingival

bleeding

Bothrops alternatus

Mild bothropic envenomings

Bothrops alternatus

Bothropic envenoming

Clinical aspectsVenom activity – Bothrops sp

2-Citotoxic venom activity – citotoxicity - capacity to destroy tissues

Venom activity – Bothrops sp

2-Citotoxic venom activity – citotoxicity - capacity to destroy tissues

Bothrops alternatus

Moderate bothropic

envenomings

Bothropic envenoming

Clinical aspects

Severe bothropic envenomings

Bothrops alternatus

Bothropic envenoming

Clinical aspectsVenom activity – Bothrops sp

2-Citotoxic venom activity – citotoxicity - capacity to destroy tissues

Venom activity – Bothrops sp

3-Hemorrhaging activity – spontaneous hemorrhage by damaging vascular endothelium

Patients develop local or distant

hemorrhage

Bothrops alternatus

Bothropic envenoming

Clinical aspects

Venom activity – Crotalus sp

1-Neurotoxic activity – neurotoxic symptoms

Crotalic envenoming Clinical aspects

Crotalus durissus terrificus

MidriasisLocal bite

Ptosis, Diplopia and blurred vision

Crotalic envenoming Clinical aspects

Crotalus durissus terrificus

Rhabdomyolysis

Increase of CPK, DHL, AST and ALT

enzymes

Myoglobinuria

Venom activity – Crotalus sp

2-Systemic rhabdomyolyses – skeletal muscle

Crotalic envenoming Clinical aspects

Crotalus durissus terrificus

Tubular necrosis causing renal failure

Venom activity – Crotalus sp

3-Renal failure

Crotalic envenoming Clinical aspects

Crotalus durissus terrificus

Liver cells with mitochondrial edemaIncrease of Alanine aminotransferase enzyme Liver necrosis

Venom activity – Crotalus sp

4-Liver toxicity

Liver with edema

Lachetic envenoming Clinical aspects

Venom activities – like Bothrops sp

1-Coagulative – cause bleeding and clotting disturbances

2-Citotoxic – citotoxicity - capacity to destroy tissues

3-Hemorrhagic – spontaneous hemorrhage by damaging vascular endothelium

4-Neurotoxic – bradicardia, diarrhea and arterial hipotension including shock

Elapidic envenoming Clinical aspects

This venom- low molecular weight neurotoxins - neurotoxic facial expression (bilateral ptosis)- respiratory muscle paralysis.

The most severe Brazilian ophidic accident!

Micrurus corallinusNeurotoxic facial

expression

NONVENOMOUS SNAKE ACCIDENTS

Boidae family

No envenomation

Wash the bite area with soap and water;

Inform the patient thatantivenom treatment is not necessary.

Accident with Boa constrictor

NONVENOMOUS SNAKE ACCIDENTS

Colubridae family

-Rare envenomation;

-Rare pain and local swelling;

-Rare partial defibrination;

-Controversial antibotropictreatment.

Envenomation by Philodryas olfersii

Thank you very much!This lecture is available at:http://www.barraviera.med.br

Emailbbviera@jvat.org.brbbviera@gnosis.com.br