Funnel-webs are probably one of the three most dangerous spiders in the world and are regarded by some to be the most dangerous.
Examination of bite records seems to indicate that wandering males have caused a large majority of fatal bites to humans, however this has not been proven. Males, recognised by the modified terminal segment of the palp, are aggressive and tend to wander during the warmer months of the year looking for receptive females of their kind for mating. They are attracted to water and hence are often found in swimming pools where they have fallen while wandering. They also show up in garages and yards in suburban Sydney.
The envenoming syndromes observed following bites by all these spiders are identical. The bite is initially very painful due to the acidity of the venom and the size of the fangs penetrating the skin. Systemic envenoming may follow the local effects. Early symptoms of systemic envenoming include tingling around the mouth and tongue, facial muscle twitching, nausea, vomiting, profuse sweating, salivation, and shortness of breath. Patients may rapidly develop agitation, confusion and coma associated with hypertension, metabolic acidosis, dilation of the pupils, generalised muscle twitching and pulmonary oedema. Death results from progressive hypotension or possibly raised intracranial pressure resulting from cerebral oedema.
The onset of severe envenoming is rapid; in one prospective study, the median time to onset of envenoming was 28 minutes, with only two cases having onset after 2 hours (both had pressure immobilization bandages applied). Deaths may occur within a period ranging from 15 minutes (this occurred when a small child was bitten) to three days.
