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.
Eastern green mamba
The eastern green mamba is a highly venomous snake. The venom consists of both pre-synaptic and postsynaptic neurotoxins (dendrotoxins), cardiotoxins, calcicludine, and fasciculins. The average venom yield per bite is 80 mg according to Engelmann and Obst (1981), while Minton (1974) gives it a range of 60–95 mg (dry weight). The subcutaneous LD is 1.3 mg/kg. The LD in mice through the IV route is 0.45 mg/kg. Like all other mamba species, the toxicity of individual specimens within the same species can vary greatly based on several factors including geographical region, age, seasonal variation, diet, and so on. Local swelling is variable and sometimes absent after mamba bites. However, patients bitten by the eastern green mamba develop swelling of the entire bitten limb and also show mild haemostatic disturbances (Warrell DA; MacKay et al. 1966). The rare cases of local tissue damage usually resulted from bites on the fingers or the use of a tight tourniquet. This species has caused bites to humans and many of the bites attributed to this species have often resulted in fatalities. The mortality rate of untreated bites is unknown but is thought to be quite high. Symptoms of envenomation by this species include swelling of the bite site, dizziness, and nausea, accompanied by difficulty breathing and swallowing, irregular heartbeat, convulsions, rapid progression to respiratory paralysis. Bites that produce severe envenomation can be rapidly fatal. Case reports of rapidly fatal outcomes, in as little as 30 minutes, have been recorded for this species.