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Vector Borne Diseases. Stephanie Skipper Ecology. Vector Borne Diseases. a disease that is transmitted to humans or other animals by an insect such as a mosquito or another arthropod is called a vector-borne disease .
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Vector Borne Diseases Stephanie Skipper Ecology
Vector Borne Diseases • a disease that is transmitted to humans or other animals by an insect such as a mosquito or another arthropod is called a vector-borne disease. • Nearly half of the world's population is infected by vector-borne diseases, resulting in high morbidity and mortality • There are many types of vector borne diseases: Denque Fever, Japanese Encephalitis, Yellow Fever, West Nile Virus,and Lyme Disease.
Dengue and dengue hemorrhagic Image: The stylets (needle-like structures) and proboscis (elongated mouth) of an Aedes aegypti feeding. Dengue viruses are transmitted during the feeding process. Denque Fever • Dengue is primarily a disease of the tropics, and the viruses that cause it are maintained in a cycle that involves humans and Aedes aegypti, a domestic, day-biting mosquito that prefers to feed on humans. • Infection with dengue viruses produces a spectrum of clinical illness ranging from a nonspecific viral syndrome to severe and fatal hemorrhagic disease. Important risk factors for DHF include the strain and serotype of the infecting virus, as well as the age, immune status, and genetic predisposition of the patient
Image: Culex mosquito laying eggs.(Photograph by Richard G. Weber)(View enlarged image.) Encephalitis • Aseptic meningitis or encephalitis. Many cases have only fever with headache • Can progress to focal paralysis, intractable seizures, coma and death • Varies with occurrence and intensity of epidemic transmission; usually 150-3,000 cases/year • Infrequent but unpredictable epidemics • No human vaccines available • Treatment not always effective • Knowledge of geographic distribution incomplete ------------------------------------------------------------- • Japanese encephalitis (JE) virus: flavivirus antigenically related to St. Louis encephalitis virus • Leading cause of viral encephalitis in Asia with 30-50,000 cases reported annually • Mosquito-borne Culex tritaeniorhynchus group
Yellow Fever • Yellow fever occurs only in Africa and South America. In South America sporadic infections occur almost exclusively in forestry and agricultural workers • The virus damages many body tissues, but especially the liver. • The Aedes Aegypti mosquito carries the yellow fever virus from one person to another. • Yellow fever is found in jungle areas, especially in South America. The disease can now be prevented by a vaccine.
Lyme disease is caused by the bacterium, Borrelia burgdorferi. These bacteria are transmitted to humans by the bite of infected deer ticks and caused more than 23,000 infections in the United States in 2002 • Lyme disease was named in 1977 when arthritis was observed in a cluster of children in and around Lyme, Conn
West Nile Virus • West Nile virus (WNV) has emerged in recent years in temperate regions of Europe and North America, presenting a threat to public and animal health. The most serious manifestation of WNV infection is fatal encephalitis (inflammation of the brain) in humans and horses, as well as mortality in certain domestic and wild birds. WNV has also been a significant cause of human illness in the United States in 2002 and 2003.
Agricultural practices and deforestation, increase the risk for vector-borne disease transmission Consumer products make ideal breeding sites for domesticated mosquitoes. Packaged in nonbiodegradable plastics, cellophanes, and tin, these products tend to be discarded in the environment where they collect rainwater. Discarded automobile tires, many in the domestic environment, make ideal mosquito breeding places as well as rat and rodent harborages. Major global demographic and societal changes of the past 50 years have directly affected the emergence/resurgence of vector-borne and other infectious diseases. Unprecedented population growth, mostly in developing countries, resulted in major movements of people, primarily to urban centers. This unplanned and uncontrolled urbanization (inadequate housing, deteriorating water, sewage, and waste management systems) produced ideal conditions for increased transmission of mosquito-borne, rodent-borne, and water-borne diseases. How does vector borne diseases relate to ecology
Interesting new fact • Some scientist once thought that mosquitoes could pass along aids
Person who affected by dengue fever – after 5 hours of contact Vector borne diseases
Dead bird affected by West Nile virus Vector borne diseases
Works cited • Gubler DJ. Insects in Disease Transmission. In: Strickland GT, editor. Hunter tropical medicine, 7th edition. Philadelphia (PA): W. B. Saunders; 1991. p. 981-1000. • Hammon WM. Dengue hemorrhagic fever–do we know its cause? Am J Trop Med Hyg 1973;22:81-91 • www.cdc.gov