Viral hemorrhagic fevers

Infection rates are rising again in Asia and the Americas. List of epidemicsColumbian Exchangeand Globalization and disease There have been a number of significant pandemics recorded in human historygenerally zoonoses which came about with domestication of animals, such as influenza and tuberculosis. There have been a number of particularly significant epidemics that deserve mention above the "mere" destruction of cities:

Viral hemorrhagic fevers

The "yellow" in the name refers to the jaundice that affects some patients. Symptoms of yellow fever include fever, headache, jaundice, muscle pain, nausea, vomiting and fatigue.

A small proportion of patients who contract the virus develop severe symptoms and approximately half of those die within 7 to 10 days. The virus is endemic in tropical areas of Africa and Central and South America. Large epidemics of yellow fever occur when infected people introduce the virus into heavily populated areas with high mosquito density and where most people have little or no immunity, due to lack of vaccination.

In these conditions, infected mosquitoes of the Aedes aegypti specie transmit the virus from person to person. A single dose of yellow fever vaccine is sufficient to confer Viral hemorrhagic fevers immunity and life-long protection against yellow fever disease.

Viral hemorrhagic fevers - Symptoms and causes - Mayo Clinic

A booster dose of the vaccine is not needed. Good supportive treatment in hospitals Viral hemorrhagic fevers survival rates.

There is currently no specific anti-viral drug for yellow fever. With more than 50 partners involved, the EYE partnership supports 40 at-risk countries in Africa and the Americas to prevent, detect, and respond to yellow fever suspected cases and outbreaks.

The partnership aims at protecting at-risk populations, preventing international spread, and containing outbreaks rapidly.

Byit is expected that more than 1 billion people will be protected against the disease. Signs and symptoms Once contracted, the yellow fever virus incubates in the body for 3 to 6 days.

Many people do not experience symptoms, but when these do occur, the most common are fever, muscle pain with prominent backache, headache, loss of appetite, and nausea or vomiting. In most cases, symptoms disappear after 3 to 4 days. A small percentage of patients, however, enter a second, more toxic phase within 24 hours of recovering from initial symptoms.

High fever returns and several body systems are affected, usually the liver and the kidneys. Bleeding can occur from the mouth, nose, eyes or stomach.

Half of the patients who enter the toxic phase die within 7 - 10 days. Diagnosis Yellow fever is difficult to diagnose, especially during the early stages. A more severe case can be confused with severe malaria, leptospirosis, viral hepatitis especially fulminant formsother haemorrhagic fevers, infection with other flaviviruses such as dengue haemorrhagic feverand poisoning.

Polymerase chain reaction PCR testing in blood and urine can sometimes detect the virus in early stages of the disease. Populations at risk Forty seven countries in Africa 34 and Central and South America 13 are either endemic for, or have regions that are endemic for, yellow fever.

A modelling study based on African data sources estimated the burden of yellow fever during was 84 — severe cases and 29 —60 deaths. Occasionally travellers who visit yellow fever endemic countries may bring the disease to countries free from yellow fever.

In order to prevent such importation of the disease, many countries require proof of vaccination against yellow fever before they will issue a visa, particularly if travellers come from, or have visited yellow fever endemic areas.

Signs and symptoms

In past centuries 17th to 19thyellow fever was transported to North America and Europe, causing large outbreaks that disrupted economies, development and in some cases decimated populations.

Transmission The yellow fever virus is an arbovirus of the flavivirus genus and is transmitted by mosquitoes, belonging to the Aedes and Haemogogus species.

The different mosquito species live in different habitats - some breed around houses domesticothers in the jungle wildand some in both habitats semi-domestic.

There are 3 types of transmission cycles: Sylvatic or jungle yellow fever: In tropical rainforests, monkeys, which are the primary reservoir of yellow fever, are bitten by wild mosquitoes of the Aedes and Haemogogus species, which pass the virus on to other monkeys.

Occasionally humans working or travelling in the forest are bitten by infected mosquitoes and develop yellow fever. In this type of transmission, semi-domestic mosquitoes those that breed both in the wild and around households infect both monkeys and people.

Increased contact between people and infected mosquitoes leads to increased transmission and many separate villages in an area can develop outbreaks at the same time. This is the most common type of outbreak in Africa.The Ebola outbreak that began in West Africa in early is the worst outbreak of this virus in history.

The Ebola virus has a high mortality rate: in the three countries most affected by the. Viral haemorrhagic fevers: WHO health topic page on viral haemorrhagic fevers provides links to descriptions of activities, reports, publications, statistics, news, multimedia and events, as well as contacts and cooperating partners in the various WHO programmes and offices working on this topic.

Viral hemorrhagic fevers

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Hemorrhagic Fevers: MedlinePlus

A wide range of viruses can cause viral hemorrhagic fever (VHF) and hence are designated as hemorrhagic fever viruses. All possess single-stranded RNA (which requires reverse transcriptase for multiplication or amplification by polymerase chain reaction [PCR]) All possess a lipid envelope;.

Viral hemorrhagic fevers (VHFs) refer to a group of illnesses that are caused by several distinct families of viruses.

Viral hemorrhagic fevers

In general, the term "viral hemorrhagic fever" is used to describe a severe multisystem syndrome (multisystem in that multiple organ systems in the body are affected. Free Service Espanol Portugues Deutsch Italiano Francais Norsk: Ethnic & Traditional Uses of Rainforest Plants.

This quick reference guide is a useful overview of the extensive information provided for each plant in Section 3.

CBRNE - Viral Hemorrhagic Fevers: Background, Pathophysiology, Epidemiology