Hemorrhagic Fever

Hemorrhagic fever is a bleeding disorder caused due to RNA viruses, mainly belonging to 4 different families of viruses. These viruses cause different types of this condition, but the basic manifestation and symptoms of the disease remain the same. The disease is characterized by bleeding organs. Depending on the type of infection the severity of the diseases varies. The Ebola virus causes the most serious and fatal form of this disorder. It is a serious multisystem syndrome, where the entire vascular system is damaged or rather infected.

Types of Viruses Causing Hemorrhagic Fever
The table below gives the 4 families of RNA viruses which cause this condition.

Virus	Type of Fever
Arenaviridae	Lassa fever, Argentine, Bolivian, Brazilian,Venezuelan hemorrhagic fever
Bunyaviridae	Hemorrhagic fever with renal syndrome, Crimean-Congo hemorrhagic fever
Filoviridae	Ebola hemorrhagic fever
Flaviviridae	Dengue, yellow fever

These RNA viruses have a lipid envelope. They require an animal or human as host for survival or multiplication.

How are Viruses Transmitted to Humans
The viruses show different mutations depending on the geographical location. The occurrence of such fevers is very sporadic and mostly infects humans only when they come in contact with another infected host which can be an animal belonging to a different species. Viruses that are carried by rodents are transmitted to humans when they come in contact with urine, saliva or the fecal matter of these rodents. Mosquitoes also act as vectors for the transmission of these viruses to humans. An example of this transmission is a mosquito bite especially that of an Aedes Aegypti which causes dengue fever, which is a type of this fatal condition.

Symptoms
The severity of the symptoms may differ for each type. However, in the initial stages the symptoms are the same which include:

• Fever
• Fatigue
• Dizziness
• Muscle ache
• Dehydration

These symptoms are common for many fevers, later on the symptoms begin to get severe if not detected. Severe cases show bleeding under the skin, internal organs and also bleeding from the orifices of the body such as the mouth, nose, ears and even eyes. However, you must bear in mind that the cause of death in severe cases is not excessive bleeding, it is the failure of organs beginning with liver as seen in yellow fever, nervous system malfunction which may lead to delirium and eventually progress to a coma. The pathophysiology of the disease varies with the type of infection, dengue causes a pathophysiology called antibody dependent enhancement, whereas Ebola fever causes disseminated intravascular coagulation. Both these processes are very complex and cannot be covered within the scope of this article.

Treatment
There is no specific form of treatment available for this condition. The treatment is a supportive therapy wherein the symptoms can be treated. However, Ribavirin an anti-viral drug has proven to be effective in the treatment of Lassa fever and hemorrhagic fever with renal syndrome. The Argentine type is being treated using the convalescent-phase plasma.

Prevention and Control
Viruses spread through hosts such as rodents, arthropods and insects such as mosquitoes. Therefore the best way to prevent the outbreak of this infection is rodent control. Cleaning up of the places infested by such rodents must be done carefully. A person who is infected must be quarantined to control the disease.

The condition we are discussing is not always fatal. It is important to remember that maintaining hygiene is the best way to prevent this fatal infection. A clean environment is a key to healthy living keeping most of the diseases at bay.