Several conditions should be considered in the differential diagnosis, such as: snake bites, spider envenomation, poisoning caused by cholinesterase inhibitors, neuroleptic drug overdose, Guillain–Barré syndrome, tetanus, poliomyelitis, botulism, myasthenia gravis, encephalitis, meningitis, subdural hematoma and diphtheria [49]. This evidence concerns the gene BCHE and tetanus.