RNA Virus Zoonotic. several viruses These are typically carried by rodent hosts and transmitted through aerosol or contact. The more serious of these cause Hemorrhagic fever. For the most part, these are issues in the world, not the U.S. Bolivian Hemorrhagic fever, Venezuelan hemorrhagic fever, Lassa fever (Africa), and Brazilian hemorrhagic fever. Characteristically, the overall vascular system is damaged, and the body's ability to regulate itself is impaired. These symptoms are often accompanied by hemorrhage (bleeding); however, the bleeding is itself rarely life-threatening. While some types of hemorrhagic fever viruses can cause relatively mild illnesses, many of these viruses cause severe, life-threatening disease. RNA Virus U.S. ZOONOTIC. Arbovirus These viruses replicate in the vector (usually a mosquito) but they do not hurt it. The mosquito transfers the virus from on individual to another by biting the first, sucking blood that contains the virus, and then biting another individual. Control of arboviruses is often centered on control of mosquitoes. The arboviruses are a diverse group, but most of the ones in this category are members of the subfamily alphaviridae and they cause encephalitis. Eastern Equine Encephalitis is of major concern to the horse industry because it can rapidly move through a herd. The horse becomes sick 1-3 weeks after infection. Eventually brain lesions appear, causing drowsiness, drooping ears, circling, aimless wandering, inability to swallow and abnormal gait. Paralysis follows, causing the horse to have difficulty raising its head. The horse usually dies within 4 days of exhibiting symptoms. Fatality rate in horses is around 80%. Human symptoms for this disease (gotten not from the horse but a mosquito) include high fever, muscle pain, altererd mental status, headache, photophobia and seizures. These occur 3-10 days after the bite of an infected mosquito. There is not treatment other than supportive therapy. RNA Virus Zoonotic. Filovirus Highly virulent. Highly fatal. Transmitted by contact. Case fatality rate as high as 90% for some strains. A disease of Africa, first noted around the Ebola river. Sudden onset of flu-like symptoms - malaise, fever with chills, arthralgia, myalgia, chest pain. Nausea accompanied by adbdominal pain, anorexia, diarrhea, and vomiting. Respiratory tract involvement with sore throat, cough, dyspnea and hiccups. CNS involvement includes severe headaches, agitation confusion fatigue, depression seizures and sometimes a coma. Also may have skin involvement with maculopapular rash, petechia, purpura, ecchymoses and hematomas. Basically, every tissue of your body is affected. Death is typically due to multiple organ dysfunction. This disease appeared in about 1976 and we have yet to understand where it came from. The best current guess is that is caught from bats in the region. RNA Virus WORLD. Flavivirus Japanese encephalitis (JE) virus is the leading cause of vaccine-preventable encephalitis in Asia and the western Pacific. For most travelers to Asia, the risk for JE is very low but varies based on destination, duration of travel, season, and activities. JE virus is maintained in a cycle involving mosquitoes and vertebrate hosts, mainly pigs and wading birds. Humans can be infected when bitten by an infected mosquito. Most human infections are asymptomatic or result in only mild symptoms. However, a small percentage of infected persons develop inflammation of the brain (encephalitis), with symptoms including sudden onset of headache, high fever, disorientation, coma, tremors and convulsions. About 1 in 4 cases are fatal. RNA Virus U.S. ZOONOTIC. Flavivirus This has been known to exist in Uganda, Africa for quite a while. But in the last 10 years it has moved to be a world-wide disease. It is transmitted by mosquitoes. 80% of West Nile infections are subclinical. When symptoms do occur, they are fever, headaches, fatigue, muscle pain, malaise, nausea, anorexia, vomiting, myalgias and rash. Less than 1% of the cases are severe and result in neurological disease Once again, it is the very young, the elderly, and the immunosuppressed that are at highest risk. We control the disease by controlling the mosquito population.