VIRAL HEMORRHAGIC FEVERS
Ebola
Pathogen(s):
- Ebolavirus
- Zaire ebolavirus (ZEBOV)
- Sudan ebolavirus (SEBOV)
- Reston ebolavirus (REBOV)
- Coted'Ivoire ebolavirus (CIEBOV)
Environmental Triggers:
- Deforestation
- Urbanization
Epidemiology:
Outbreaks of EVD have mainly been restricted to Africa. The virus often consumes the population. Governments and individuals quickly respond to quarantine the area while the lack of roads and transportation helps to contain the outbreak. EVD was first described after almost simultaneous viral hemorrhagic fever outbreaks occurred in Zaire and Sudan in 1976.EVD is believed to occur after an ebolavirus is transmitted to a human index case via contact with an infected animal host. Human-to-human transmission occurs via direct contact with blood or bodily fluids from an infected person (including embalming of a deceased victim) or by contact with contaminated medical equipment such as needles. In the past, explosive nosocomial transmission has occurred in underequipped African hospitals due to the reuse of needles and/or absence of proper barrier nursing. Aerosol transmission has not been observed during natural EVD outbreaks. The potential for widespread EVD epidemics is considered low due to the high case-fatality rate, the rapidity of demise of patients, and the often remote areas where infections occur.
Photo Source: nim.nih.gov
Dengue Fever
Classification(s):
- Dengue Shock Syndrome
- Dengue Hemorrhagic Fever
- Breakbone Fever
Pathogen(s):
- Dengue Fever Virus
Environmental Triggers:
- Deforestation
- Urbanization
- Globalization of Travel and Trade
- Habitat Conversion
- Cycles of Poverty
- Population Growth
- Pollution
Epidemiology:
Most people with dengue recover without any ongoing problems. The mortality is 1–5% without treatment, and less than 1% with adequate treatment; however severe disease carries a mortality of 26%. Dengue is endemic in more than 110 countries.It infects 50 to 100 million people worldwide a year, leading to half a million hospitalizations, and approximately 12,500–25,000 deaths.
The most common viral disease transmitted by arthropods, dengue has a disease burden estimated to be 1600 disability-adjusted life years per million population, which is similar to other childhood and tropical diseases such as tuberculosis.As a tropical disease dengue is deemed only second in importance to malaria, though the World Health Organization counts dengue as one of sixteen neglected tropical diseases.
The incidence of dengue increased 30 fold between 1960 and 2010.This increase is believed to be due to a combination of urbanization, population growth, increased international travel, and global warming.The geographical distribution is around the equator with 70% of the total 2.5 billion people living in endemic areas from Asia and the Pacific.In the United States, the rate of dengue infection among those who return from an endemic area with a fever is 2.9–8.0%, and it is the second most common infection after malaria to be diagnosed in this group.
Until 2003, dengue was classified as a potential bioterrorism agent, but subsequent reports removed this classification as it was deemed too difficult to transfer and only caused hemorrhagic fever in a relatively small proportion of people.
Like most arboviruses, dengue virus is maintained in nature in cycles that involve preferred blood-sucking vectors and vertebrate hosts. The viruses are maintained in the forests of Southeast Asia and Africa by transmission from female Aedes mosquitoes—of species other than A. aegypti—to her offspring and to lower primates. In rural settings the virus is transmitted to humans by A. aegypti and other species of Aedes such as A. albopictus. In towns and cities, the virus is primarily transmitted to humans by A. aegypti, which is highly domesticated. In all settings the infected lower primates or humans greatly increase the number of circulating dengue viruses. This is called amplification.The urban cycle is the most important to infections of humans and dengue infections are primarily confined to towns and cities.In recent decades, the expansion of villages, towns and cities in endemic areas, and the increased mobility of humans has increased the number of epidemics and circulating viruses. Dengue fever, which was once confined to Southeast Asia, has now spread to Southern China, countries in the Pacific Ocean and America, and might pose a threat to Europe.
Photo Source: thailandtimes.asia
Hantavirus
Classification(s):
- Hantavirus Pulmonary Syndrom (HPS)
- Hemorrhagic Fever with Renal Symptoms (HFRS)
- Hantaan Virus (HTNV)
Pathogen(s):
- Hantavirus
Environmental Triggers:
- Defaunation
- Global Warming
- Cycles of Poverty
Epidemiology:
Regions especially affected by HFRS include China, the Korean Peninsula, Russia (Hantaan, Puumala and Seoul viruses), and northern and western Europe (Puumala and Dobrava virus). Regions with the highest incidences of HCPS include Patagonian Argentina, Chile, Brazil, the United States, Canada, and Panama, where a milder form of disease that spares the heart has been recognized. The two agents of HCPS in South America are Andes virus (also called Oran, Castelo de Sonhos, Lechiguanas, Juquitiba, Araraquara, and Bermejo viruses, among many other synonyms), which is the only hantavirus that has shown (albeit uncommonly) an interpersonal form of transmission, and Laguna Negra virus, an extremely close relative of the previously-known Rio Mamore virus. In the U.S., minor cases of HCPS include New York virus, Bayou virus, and possibly Black Creek Canal virus.
In the United States, as of July 2010 eight states had reported 30 or more cases of Hantavirus since 1993[9] - New Mexico (84), Colorado (70), Arizona (62), California (42), Washington (41), Texas (37), Utah (31) and Montana (30). Other states reporting a significant number of cases include Idaho (16), Kansas (15), South Dakota (15), and North Dakota (12). With only 11 cases, Oregon has a notably lower attack rate overall and relative to population, compared to other Western states.
Photo Source: wildlifemanagementpro.com