Antivenom in Nepal

Snake bite is one of the tropical diseases which is listed by WHO but most neglected by the government officials of poor countries like Nepal. Each year it is estimate that more than 5 million people are bitten each year with up to 2.5 million envenomings. Nepal can't remain untouched . It is estimated that more than 20 thousand people are bittten by snakes with toll crosses more than 1000. But being a poor health data, it has been recorded that less than 100 people died due to snake bite. 

Bites by venomous snakes can cause acute medical emergencies involving severe paralysis that may prevent breathing; bleeding disorders that can lead to fatal haemorrhage; irreversible kidney failure and severe local tissue destruction that can cause permanent disability and may result in limb amputation. Children suffer more severe effects than adults due to their smaller body mass.

In contrast to many other serious health conditions, a highly effective treatment exists. Most deaths and serious consequences from snake bites are entirely preventable by making antivenom more widely available. Snake antivenoms are the only effective treatment to prevent or reverse most of the venomous effects of snake bites. They are included in the WHO List of Essential Medicines and should be part of any primary health care package where snake bites occur.

In the same senario, the government is unable to provide the sufficient amount of anti venom sera when in need. At a workshop on 'Production of Anti-snake Venom in Nepal' it has been mentioned that that production of the anti-snake venom in Nepal is extremely necessary. Various experts are being called from zoology department, doctors and politicians with no pharmacist. Its one of the field of the pharmacist and bio-technologist where they can contribute in this sector and promote the public health of tarai region of Nepal.

The major supplier of snake antivenome sera for Nepal is India. Total dependent on the Indian producer which some time leads to shortage of serum. As per the Hari Bhakta Sharma, founder and executive director of Deurali Janta Pharmaceuticals, the production of the antivenom can begin within 2 years, provided that government provide subsidy on those serum. As producing 40,000 vaccines investing more than Rs 500 million will be business of failure." But what if Nepali producer  target the Indian market. 

Here are the steps for the production of Anti venom sera:

Step 1: Milking The Venom

Today the process of creating antivenom is carefully controlled, but essentially done the same way. Snakes are kept in quarantine to make sure they are healthy and then caught up. The snake’s fangs are pushed through a thin layer of plastic covering a vial. Then its glands are gently squeezed in order to empty the snake’s store of venom into the vial. However, this is still only a minute amount of venom and snakes must be milked numerous times in order to get a workable amount of venom. Thousands of snakes has to be milked for few milliliters of snake venom.

Step 2: Labeling and Freezing 

The beaker collects the venom, which is desiccated under vacuum or freeze-dried. After drying, the venom crystals are carefully scraped from the beakers for weighing and packaging. Trained staff, who work with the venom in its various stages of processing, wear protective masks to avoid poisoning.  The venom is then frozen and freeze-dried for transport.

Step 3: Selection of Animal

The next step is to inject small amounts of venom into an animal that can create antibodies. Horses have often been used, but many people are allergic to the horse-based antivenom. So sheep and goats are also used frequently. A veterinarian looks over the process, checking on the animal’s well-being and it takes 8 to 10 weeks for antibodies to peak in the animal’s bloodstream. 

Step 4: Isolation of antivenom sera

The next step in the antivenom fabrication process is purification. The blood is ran through a centrifuge to filter the plasma – the liquid portion of blood that doesn’t contain blood cells – to allow the antivenom to be separated. During this step, producers typically employ their own methods and many keep them a trading secret. Typically, though, unwanted proteins are discarded through precipitation, often by adjusting the plasma’s pH or adding salts to the solution.  One of the last steps involves using an enzyme to breakdown the antibodies and isolate the active ingredients. The last step involves checking, usually by an outside regulatory body like the FDA in the United States. Once approved, the samples are concentrated under powder or liquid form, frozen and shipped to hospitals where they’re most needed

Challenges producing antivenoms

A significant challenge in manufacturing of antivenoms is the preparation of the correct immunogens (snake venoms). At present very few countries produce snake venoms of adequate quality for antivenom manufacture. In addition, lack of regulatory capacity for the control of antivenoms in countries with significant snake bite problems results in an inability to assess the quality and appropriateness of the antivenoms.

For details:

1. Possiblity of antivenom production in Nepal: Nagarik news

2. Fact sheet of WHO on snake bites: WHO

3. Snake Venom Guideline by WHO: Guideline

4. Snake Venom research in Australia: Australia Reptile Park