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.
David Sharp (mountaineer)
Also, the human body's response to increasingly high altitudes is difficult to predict, regardless of prior instances of functioning at lower altitudes or previous experience at high altitudes. For example, Igor Plyushkin, a Snow Leopard award-winning climber (having summited all five mountains in the former Soviet Union), died on 22 May 2006 while attempting to summit Everest, despite being with a group who gave him extra oxygen and medicine at just . Another climber, Brazilian mountaineer Vitor Negrete, died on 19 May 2006, having written about his difficulties on his blog. Negrete had summited Everest In 2005, and was attempting to do so again, but without the aid of extra oxygen. Negrete was aware that Sharp had died as he set out on his own fatal summit climb. Just days after Sharp's demise, and after several unfortunate occurrences, he reached the summit alone — without oxygen, a sherpa, radio, or a satellite phone — but died during his descent. The fate of climbers like Negrete illustrates why climbers are advised to bring a radio, use bottled oxygen at higher altitudes and have at least one climbing partner: altitude sickness can occur suddenly and without warning, leaving a climber disoriented and "nutty".