A new study from the University of Queensland (UQ) in Australia sheds light on a clinical mystery that has long intrigued doctors: why do some patients bitten by mambas recover with the antivenom but deteriorate again shortly afterwards? The answer may lie in the surprising complexity of the venom of these highly dangerous snakes.
The investigation, led by Professor Bryan Fry of the UQ School of the Environment, analyzed the venoms of three mamba species — the black mamba, the western green mamba, and Jameson’s mamba — and revealed that they act in a far more sophisticated way than had been previously thought.
According to Fry, the venom of these species induces two distinct types of paralysis, acting on different parts of the nervous system. Initially, it causes flaccid paralysis by interrupting the communication between nerves and muscles (post-synaptic neurotoxicity). This effect is usually successfully treated by the available antivenom. However, the study demonstrated that once this action is neutralized, a second mechanism comes into play: presynaptic toxicity that provokes spastic paralysis, with intense and painful muscle spasms.
“It’s like treating one disease and discovering another right afterwards,” describes Fry. “The venom first blocks nerve signals, but after the antivenom is administered, there is over-stimulation of the muscles, leading to involuntary and painful contractions.”
Until now, it was thought that only the eastern green mamba could cause this second type of paralysis. The new evidence helps to explain why, in some cases, patients initially appear to improve, regaining mobility and muscle tone, but shortly afterward again develop severe neurological symptoms.
The study, published in the scientific journal Toxins, highlights important limitations in the antivenoms currently used, which were not designed to deal with both types of toxicity simultaneously. The situation is further complicated by regional variations in venom, particularly among the Kenyan and South African populations of the black mamba, which makes treatment even less effective.
Mamba bites pose a significant threat in Sub-Saharan Africa, with estimates pointing to around 30,000 deaths per year. The need for more effective and specific antivenoms is, according to the researchers, urgent.
Lee Jones, a doctoral student responsible for the laboratory tests, stresses the importance of the advancement: “We have discovered that current antivenoms can, inadvertently, reveal other hidden effects of the venom. This changes the way we view the treatment of mamba envenomations.”
The team emphasizes that the research is not merely theoretical, but a clear call to action for doctors, health authorities, and antivenom manufacturers. “This kind of study has a direct impact on clinical practice and can save lives,” Fry concludes.
The work was carried out in collaboration with the Monash Venom Group and could pave the way for the development of a new generation of antivenoms, more effective and adapted to the complexity of mamba venoms.
