Orientia tsutsugamushi
"O. tsutsugamushi" causes a complex and dangerous infection scrub typhus. Infection starts when chiggers bite on the skin during their feeding. The bacteria are deposited at the site of feeding (inoculation), where they multiply. They cause progressive tissue damage (necrosis). Necrosis progresses to inflammation of the blood vessels called vasculitis. This in turn causes inflammation of the lymph nodes, called lymphadenopathy. Within a few days, vasculitis extends to various organs including liver, brain, kidney, meninges and the lung. The disease is responsible for nearly a quarter of all the febrile (high fever) illness in endemic areas. Mortality in severe case or due to improper treatment or misdiagnosis may be as high as 30-70%. About 6% of infected people die untreated, and 1.4% of the patients die even with medical treatment. Moreover, death rate can be as high as 13% where medical treatment is not properly handled. In cases of misdiagnosis and failure of treatment, systemic complications rapidly develop including acute respiratory distress syndrome, acute kidney failure, encephalitis, gastrointestinal bleeding, hepatitis, meningitis, myocarditis, pancreatitis, pneumonia, septic shock, sub-acute thyroiditis, and multi-organ dysfunctions. Harmful symptoms involving multiple organ failure and neurological impairment are difficult to treat, and can be lifelong debilitation or directly fatal. The central nervous system is often affected and result in various complications including cerebellitis, cranial nerve palsies, meningoencephalitis, plexopathy, transverse myelitis, neuroleptic malignant syndrome, and Guillan-Barré syndrome. Death rates due to complications can be up to 14% in brain infections, and 24% with multiple organ failure. It is the major cause of acute encephalitis syndrome in India, where viral infection Japanese encephalitis has been regarded as the main factor.
Bothrops insularis
Because "B. insularis" is only found in an area uninhabited by humans, there has never been an official report of a human being bitten by one, but other lanceheads are responsible for more human mortality than any other group of snakes in either North or South America. Ludwig Trutnau reports four human envenomations, three of which were fatal. The mortality rate for lancehead envenomations is 0.5–3% if the patient receives treatment and 7% if the patient does not receive treatment. The effects of envenomations by lanceheads include swelling, local pain, nausea and vomiting, blood blisters, bruising, blood in the vomit and urine, intestinal bleeding, kidney failure, hemorrhage in the brain and severe necrosis of muscular tissue. Chemical analysis of the venom of "B. insularis" suggests that it is five times as potent as that of "B. jararaca" and is the fastest acting venom in the genus "Bothrops". They have hemotoxic venom that eats away at flesh and tissue to digest the prey item before they swallow it. "Bothrops insularis" also have some neurotoxic venom that kills the prey item.