Besides Penicillin and Aspirin there’s one more drug which arguably can be capped as an all time most valuable drug specially for the poorest of mankind and yet has its origin in the most modest of all the resources - the ordinary ‘soil ‘.
This drug is known as “ Ivermectin “ which is beneficial in the treatment of varieties of simple yet socioeconomically devastating disease such as onchocerciasis ( river blindness) ,lymphatic filariasis, ascariasis ( round worm ) and an array of very common skin conditions like pediculosis ( lice) and scabies ( mite) which is generally associated with abject poverty and ignorance .
It’s also known as a block buster drug for veterinarians treating a host of animal parasitic conditions.
Little wonder that it’s discovery was found eminently suitable for Nobel prize in Physiology or Medicine albeit quite late in the year 2015 and was awarded to Dr William C . Campbell (USA) and Dr Satoshi Omura (Japan).
Incidentally, this is the same drug, which continues to create a lot of flutter and debate in the treatment of dreaded COVID 19 and why not? For its range of usefulness and ease of use it is appropriately nicknamed as “miracle drug “‘
!Dr Omura, a microbiologist from Kitosato Institute Tokyo, a strong believer in nature, isolated a soil bacteria known as ‘Streptomyces avermitilis ‘which was found typically around a golf course in Japan. It’s interesting to note that till date this novel bacteria has not been found in any other soil other than the soil of the afore said Japanese golf course !
Omura was studying microbes in the soil and came across novel bacteria which were entirely different in its growth characteristics from others which made it worth examining and pursuing for its antibiotic effects. He soon contacted Dr Campbell, an expert parasite pharmacologist from USA who was working for a pharmaceutical giant MSD.
MECHANISM OF ACTION
Ivermectin acts on glutamate gated chloride ion channels present in the nerves and muscles of many parasites by hyper polarising them. This leads to paralysis of the larvae and such paralysed organisms are subsequently eliminated by scavenging system of the host.
Dr Campbell had a very simple plan of study. He infected experimental mice with worms and parasites to make them sick and then treated them by above-mentioned soil bacteria introduced through its feed. To his utter surprise it resulted into killing of those parasites straight away and thus curing the animal of the aforementioned disease. This simple but straight forward approach was extended to a host of animal parasitic conditions one by one and was greeted with unqualified success in all most all such trials. Veterinarians had found an easy to use answer for many of their nagging animal parasitic diseases but it had to be adapted to human conditions in course of time.
FDA approved this drug initially for animal use only. However, in course of time FDA found it fit for human use as oral drug with almost no side effects in recommended dosage of upto 170 micro grams per kg body weight.
Huge success awaited its use in host of diseases helping millions of people suffering from disease such as River blindness, a disease caused by a microbe called ‘onchocerca vulvulis ‘ transmitted through repeated bites of black fly species called ‘simulium along the highly oxygenated water bodies flowing in Africa and central & South America spread from one person to the other by skin bite much like malaria . As it was present in the poorest of the poor habitat of the world even WHO did not bother much until the then UN Secretary General Kofi Annan , who himself hailed from Ghana, Africa, created a fund for neglected tropical diseases (NTD ). Much required attention towards scientific research and fund for such diseases were released and it got much needed push.
In the mean time in 70s, a leading Pharma company MSD, saw some business sense in putting money into it . Very soon original molecule derived from soil bacteria, Avermectin ‘s chemical structure was figured out and it’s much active derivative ‘Di -hydro Avermectin ‘known as ‘IVERMECTIN’ was synthesised .
It’s use in river blindness, the second most common cause of blindness in the world after trachoma, which inflicted millions of people in sub Sahara Africa, central & South America and parts of Arab peninsula for centuries was designed and treated under WHO supervision. This drug thankfully brought total control of dreaded ‘River Blindness ‘ just by giving a single oral pill of ivermectin at six monthly intervals to the entire population .Within three to four years it interrupted the life cycle of onchocerciasis by killing the microfilarial larvae present in the human body brought by blood sucking female black fly ,as mass prophylaxis as well as its treatment . Fortunately this disease ‘River Blindness ‘is not found in our part of the world, therefore the profound impact that this drug had made in the lives of millions of people was not felt here and therefore did not make much news it so much deserved .
However what we experienced here was Ivermectin’s exceptional role in treatment of filariasis due to another micro filaria of Bancroftian type ,known for disfiguring ,disabling swelling of limbs known as elephantiasis and endemic scrotal hydrocele requiring surgery for innumerable people . Now thanks to this drug, bancroftian filariasis is at the verge of its total elimination .
Ivermectin’s impactful role in curing lice and mites present on the skin surface and hair of poor people with low hygiene awareness in developing countries such as India has been no less than a boon.
Such a versatile drug with multiple modes of action can still be the most sought after drug for Covid 19 as some research papers indicate but certainly we need a more robust clinical trial to establish its use in Covid 19 with certainty.
The writer is former Professor and Head of Medicine, RIMS, Ranchi, Jharkhand.
