Just in case your inner Indiana Jones thinks it wants to go to Amazon... (quoted from The Lost City of Z)
But it wasn't the big predators that he and his companions fretted about most. It was the ceaseless pests. The sauba ants that could reduce the men's clothes and rucksacks to threads in a single night. The ticks that attached like leeches (another scourge) and the red hairy chiggers that consumed human tissue. The cyanide-squirting millipedes. The parasitic worms that caused blindness. The berne flies that drove their ovipositors through clothing and deposited larval eggs that hatched and burrowed under the skin. The almost invisible biting flies called piums that left the explorers bodies covered in lesions. Then there were the "kissing bugs," which bite their victim on the lips, transferring a protozoan called Trypanosoma cruzi; twenty years later, the person, thinking he had escaped the jungle unharmed, would begin to die of heart or brain swelling. Nothing, though, was more hazardous than the mosquitoes. They transmitted everything from malaria to "bone-crusher" fever to elephantiasis to yellow fever. "[Mosquitoes] constitute the chief single reason why Amazonia is a frontier still to be won," Willard Price wrote in his 1952 book The Amazing Amazon.
Next, Costin contracted espundia, an illness with even more frightening symptons [than malaria]. Caused by a parasite transmitted by sand flies, it destroys the flesh around the mouth, nose, and limbs, as if the person were slowly dissolving. "It develops into... a mass of leprous corruption," Fawcett said. In rare instances, it leads to fatal secondary infections. In Costin's case, the disease eventually became so bad, as Nina Fawcett later informed the Royal Geographical Society, that he had "gone off his rocker."
Murray, meanwhile, seemed to be literally coming apart. One of his fingers grew inflamed after brushing against a poisonous plant. Then the nail slid off, as if someone had removed it with pliers. Then his right hand developed, as he put it, a "very sick, deep suppurating wound," which made it "agony" even to pitch his hammock. Then he was stricken with diarrhea. Then he woke up to find what looked like worms in his knee and arm. He peered closer. They were maggots growing inside him. He counted fifty around his elbow alone. "Very painful now and again when they move," Murray wrote.(135)
Repulsed, he tried, despite Fawcett's warnings, to poison them. He put anything -- nicotine, corrosive sublimate, permanganate of potash -- inside the wounds and attempted to pick the worms out with a needle or by squeezing the flesh around them. Some worms died from the poison and started to rot inside him. Others grew as long as an inch and occasionally poked out their heads from his body, like a periscope on a submarine. It was as if his body were being taken over by the kind of tiny creatures he had studied. His skin smelled putrid. His feet swelled. Was he getting elephantiasis, too? "The feet are too big for the boots," he wrote, "The skin is like pulp."