Epidemiology
Most arboviruses are located in tropical areas, however as a group they have a global distribution. The warm climate conditions found in tropical areas allows for year-round transmission by the arthropod vectors. Other important factors determining geographic distribution of arthropod vectors include rainfall, humidity, and vegetation.Mapping methods such as GIS and GPS have allowed for spatial and temporal analyses of arboviruses. Tagging cases or breeding sites geographically has allowed for deeper examination of vector transmission.To see the epidemiology of specific arboviruses, the following resources hold maps, fact sheets, and reports on arboviruses and arboviral epidemics. History
Arboviruses were not known to exist until the rise of modern medicine, with the germ theory and an understanding that viruses were distinct from other microorganisms. The connection between arthropods and disease was not postulated until 1881 when Cuban doctor and scientist Carlos Finlay proposed that yellow fever may be transmitted by mosquitoes instead of human contact, a reality that was verified by Major Walter Reed in 1901. The primary vector, Aedes aegypti, had spread globally from the 15th to the 19th centuries as a result of globalization and the slave trade. This geographic spreading caused dengue fever epidemics throughout the 18th and 19th centuries, and later, in 1906, transmission by the Aedes mosquitoes was confirmed, making yellow fever and dengue fever the first two diseases known to be caused by viruses.Thomas Milton Rivers published the first clear description of a virus as distinct from a bacterium in 1927.
Major aortopulmonary collateral arteries (or MAPCAs) are arteries that develop to supply blood to the lungs when native pulmonary circulation is underdeveloped. Instead of coming from the pulmonary trunk, supply develops from the aorta and other systemic arteries. Pathogenesis and anatomy
Major aortopulmonary collateral arteries (MAPCAs) develop early in embryonic life but regress as the normal pulmonary arteries (vessels that will supply deoxygenated blood to the lungs) develop. In certain heart conditions the pulmonary arteries do not develop. The collaterals continue to grow, and can become the main supply of blood to the lungs. Though it is usually associated with congenital heart diseases with decreased pulmonary blood flow like tetralogy of Fallot or pulmonary atresia it may be seen sometimes in isolation i.e. not associated with any congenital heart disease in that case it is termed as isolated aortopulmonary collateral artery. In these cases it may be one of the cause of congestive cardiac failure in neonates.Pulmonary arteries come from the right side of the heart, and usually carry deoxygenated blood from the body. These collateral arteries carry blood which has already been oxygenated by the lungs, so are of little use in helping the body to get oxygen. Associated conditions
Pulmonary atresia with ventricular septal defect (or Tetralogy of Fallot with pulmonary atresia) will result in the development of systemic collaterals. Implications of a systemic collateral supply
Major aortopulmonary collateral arteries come from the systemic circulation, because of this they will often have higher pressure than normal found in the lungs, leading to pulmonary hypertension.