Bufo marinus.
Bufo marinus, commonly known as the common cane toad is native to the New World and is largely found in man-made cleared areas. They are terrestrial but can be found near rivers and ponds for the purposes of breeding; the tadpoles can withstand a 15% salt content in water, therefore breeding can also take place near sea areas. The cane toad was used in the 20th Century for the purposes of biological pest control and was therefore introduced into many places including Australia, Hawaii and many parts of the Caribbean and Oceania, where they are now viewed as pests due to their over-population. The popular name ‘Cane Toad’ is derived from the successful control of sugar cane pests, including the cane beetle, by the introduction of these toads into sugar cane plantations. More-over the toads were also used in controlling the white beetle infestations in sweet potato plantations.
The defensive mechanism of Bufo marinus is an extraordinary entourage of chemical warfare; it releases toxins from the skin and from the parotid glands behind the ears. The chemicals can be fatal with ingestion and there are documented fatal incidents among mammals, dogs, snakes and crocodiles. It is interesting to note that two types of snakes in Australia have evolved into smaller-headed snakes so that they can no longer have the capacity to swallow these cane toads. It is the generally the cardio-toxic and muscular paralysis components of the chemicals which causes fatalities and at this point I would like to point out that there is no documented evidence of anti-coagulant properties in the toad toxin. It is a popular belief in the Toledo area of Belize that if a dog exhibits bleeding problems (usually from nose and mouth) that they have been exposed to toad toxins. Most likely, the bleeding problems are caused by snake bites particularly the dreaded ‘Tommygoff” (Bothrops asper).
Research has yielded the isolation of many important chemicals of pharmacological and therapeutic value. Broadly speaking they can be classed into the following therapeutic categories:-
1) Anti-microbial: Toads secrete anti-microbial proteins inside their bodies and also secrete it through the pores of their skin. Studies have shown inhibitory effects against Staphylococcus aureus and Escherichia coli. Aryuvedic Medicine has traditionally used live toads to rub on cankers and sores of domesticated livestock which shows that the anti-bacterial activity was already put into use.
2) Anti-viral protein isolated from Bufo andrewsi has been shown to exhibit anti-HIV activity and inhibition of recombinant HIV-1 reverse transcriptase activity.
3) Cardiovascular effects: isolated toad venom has been employed in Traditional Chinese Medicine for centuries; the medical preparation is called ‘Chan’su’ which is used as a cardio-tonic. Bufalin, amongst other isolated chemicals, has shown to increase myocardial contractile activity without increasing the heart rate. The cardio-active chemicals exhibit activity similar to digitalis and therefore might be useful in controlling conduction disorders of the heart, including atrial fibrillation.
4) Psychoactive components include bufotenine and 5-MeO-DMT (from Bufo alvarius), may offer greater research potential in the field of psychiatry, particularly in the understanding of schizophrenia.
The purpose of this article is to show the myriad of uses of the Common Cane Toad. They can keep pest populations down in plantations and can act as deterrent to snakes and crocodiles. There is so much potential in the medical therapeutic value of the toad-toxin and with time, more pharmacologically useful components may be isolated which can lead to greater breakthroughs in Medicine. Who knows what may happen in the future…we might be farming cane toads for the extraction of therapeutic drugs. We need to keep an open mind and realise the great potential of everything in nature, even the Common Cane Toad.