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EPIDEMIOLOGY OF SNAKE BITE CASES IN NEPAL

Presenter:Bimal khadka Resource Faculty:Ram B. Sah

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Introduction

Nepal is a small yet beautiful Himalayan kingdom with a population of 28 million, most of whom live in a rural environment. The climate and ecology of the country is mainly determined by elevation which defines 3 ecological zones extending from east to west through out the countryThe ecological diversity is matched by species variety of snake found in different regions of the country.

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Distribution of snakesTerai region: Pan-oriental (Indian) species. high diversity of snakes in terms of species

density. (mostly Karait and cobra)Mid-hill region: 1500 and 3500 metres above

sea level. pan-oriental and Indo-chinese species.Himalayan region: northern most region above

3500 metres himalayan and and Tibetan species ( Pit vipers).

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AgricultureAgriculture is the main stay of Nepalese economy. The agriculturally prosperous terai region with hot

climate, high seasonal rainfall, lush natural vegetation, high density of rodents, rich reptiles and amphibian flora making ideal habitat for snake to live and increase availability of marshy land to undergo hibernation.

The abundance of snake and human activities, mainly agriculture, increases the man – snake encounter leading to snakebite.

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Agriculture

Cultural and Religious View:

Hindu people worship the “king of snakes” (Nag) in the snake festival (Nagpanchami) celebrated in July in mid monsoon. snakebite can be avoided rain will be assured for their crops.

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Herpetologists classified snakes:1.Colubridae i. Elapidae : -cobra, krait, mamba, coral snakes, taipan, -found in all parts of the world except Europe.

ii. Crotalidae : -rattle snake, pigmy snake, copper heads, bush master, -Asia & America

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iii. Hydrophidae: -all sea snakes, -myotoxic, -they seldom bite.

2. Viperidae : i. Viperinae: -Russell’s viper, Saw-scaled viper, Gaboon viper, -Found everywhere in the world except America.

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Worldwide: Worldwide the published statistics on the incidence, morbidity and mortality are largely based on the hospital data and is grossly inadequate except for a few countries where snakebite is rare or is correctly reported.• Snakebite is estimated to account for a tenth as

much mortality as malaria, but there is no equivalent global snakebite strategy.

• An international initiative is required to refocus the world’s attention on this neglected, but eminently treatable, disorder.

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Asia

In Asia alone, it has been estimated that four million snakebite cases occurs each year of which 50% are envenomed resulting in 100,000 annual deaths.

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Nepal

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Snakes found in Nepal

79 species of snakes are found in Nepal •

Among them 21 species are poisonous 5 sp. Of Kraits, 3 of Cobras1 sp.of Coral, 1 sp. Of Russel’s viper and and sp. of pit vipers) •

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Majority of bites and consequent mortality is attributable to 5 species:

They are the dangerously poisonous snakes in our country.

1.Ophiophagus hannah (king cobra), 2. Naja naja (common cobra),3. Daboia rusellii (Russell's viper),4. Bungarus caeruleus (krait) and5. Echis carinatae (saw-scaled viper).

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1.King Cobra (Ophiophagus hannah)

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2.Common Cobra (Naja naja)

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3. Common Krait (most common)

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4. Russell’s Viper (Daboia rusellii)

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5. Saw-scaled Viper (Echis carinatae)

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Other non-poisonous snakes in Nepal• Blind snake –tropical snakes with scales over

eyes adapted for burrowing and eating small invertebrates• tree snake-slender tree dweller native all over SE asia• Sand snake• Worm snake

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Public health problemSnake bite is a common event in many rural

areas where transportation and medical facilities are grossly inadequate.

Most of the trained health workers are urban based where snakebite is rare.

Therefore faith healers play a major role in the treatment of snakebite.

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EpidemiologyZoonotic like snake bite is medical emergency and cause

hospital admission. 79 species of snakes are found in Nepal • Around 15000 snakebite cases occur annually • Around 10% of these cases are poisonous bites • Mortality is 10% among poisonous bite • 26 district of terai including inner terai are highly

affected • Every year 85-120 people die due to poisonous snake bite

in Nepal • ASVS free distribution policy implemented since FY

2056/057 (1998/99 ) • Indian Quadri-valent ASVS is used

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Snake bite cases and deaths.

Snake bite cases and deaths

Fiscal year

Total case

Non poisonous

Poisonous

Cure No. of Deaths

% of Death

2065/66 13017 11883 1134 1006 128 11.28

2066/67 17163 15844 1319 1188 131 9.93

2067/68 18204 17121 1083 965 118 10.89

2068/69 14768 13789 979 890 89 9.09

2069/70 14329 13462 867 788 79 9.11

Total 77481 72099 5382 4837 545Source:EDCD

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Snake bite case in Ward of BpkihsFiscal year Total admitted

caseNo of deaths % of deaths

2010/11 54 3 .06

2011/12 47 1 .020

2012/13 16 0 0

2013/14 29 0 0

2014/15 36 1 .03

Total 202 4

Note : all death occurred in paediatrics ward 1 death occurred within 48 hours 3 deaths occurred after 48 hours after admission. all death occurred in Rainy season

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Snake bite case in emergency department of BPKIHSAdmitted in emergency Fiscal year

Cases in emergency

2010/11 185

2011/12 99

2012/13 43

2013/14 51

2014/15 51

Total 429

Note : 2 deaths occurred in June and July of 2011/12.

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Species of biting poisonous snake

Only poisonous snake bite cases viz. pit viper’s bite which do not need administration of anti-snake venom serum is reported from hills and mountains. So, those cases are not entertained for the purpose of analysis.

Among poisonous case, 2/3rd cases due to krait bite, 1/3rd due to cobra bite and very few cases due to Russell's viper bite, health institutions used to report dhaman bites as poisonous snake bite.

Dhaman and cobra bite frequently confused amongst healthcare providers.

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Age and sex:

• Among the genders, male are victimized slightly higher than females• Among the age group, 2/3rd of the total cases

belong to adult age group, aged > 15 years and the rest belong to the age group < 15 years. Among the dead, half belong to adult age group aged > 15 years and half belong to age group < 15 years of age.

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Time of bite

2/3rd of snake bite cases occur during night, rest in the morning & evening time.

Dusk to dawn covers 3/4th of the total poisonous snakebite cases.

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Site of bite As 2/3rd of cases are due to krait bite and happened

during night time, site of bite and mark of bite could not be conformed .

So among the site of bites mention cases, half of the people bitten on hand and rest were bitten on foot, head & neck region and other parts of body.

Other parts includes buttocks ,hip, back and chest.

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Monthly distribution of snake bite:No Reports of poisonous snakebite cases during

December, January, march. Few on February and November.

Incidence rise from month of April and remain at peak level in month of June, July, august and September (during and after monsoon).

Decline from month of October to nearly level off during December.

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Activities Development and distribution of snake bite

management guideline and treatment protocol for medical professionals of the country.

Free distribution of ASVS for the victims of poisonous snake bite.

Annually around 19000-21000 vials of ASVS is supplied for 1500-2000 people who are in high risk zones of the country, through regional medical stores and hospitals.

Training: SMO/MO and Paramedics on judicious use of ASVS

Develop and distribution of IEC materials to stakeholders

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Prevention is better than cure.In Nepal most snakebite cases occur due to

carelessness, specific occupation, lack of knowledge on the snakes and poverty.

Number of accidents can be reduced if following instruction is followedLeave snake alone, avoid it as far as possible.Avoid having rubble, rubbish, unnecessary grass and

bush close to resident and play ground.Never handle, threatened, attack and trap a snake in

an enclose space.Never put hand, feet into the holes in land, trees,

hollow logs and thick grass without prior inspection.

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Prevention is better than cure.

Always use light while walking at night. Do not gather firewood after dark. Keep the residence free of rodents, amphibians and lizard.Try to avoid indoor and outdoor sleeping on ground,sleep

in net. Take caution while waking on swamp area. Do not swim in water infested with snake.Do not believe that snakebite incidents, which takes place

inside water are harmless.People who live in the huts must check shoes before

putting them.If you are bitten, get away from the snakes as quickly as

possible in zigzag way and move to high altitude.

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ReferencesSanjib Sarma MD, drsanjib@yahoo.com, snake

and snakebite cases in Nepal , CIN’ 2003, Nepal government, Ministry of health,

Department of health services, Epidemiology & disease control division, Snakebite management guideline,2003.

Annual health report, Nepal 2012/13.BPKIHS