Marburg hemorrhagic fever overview

# Overview
The Marburg virus causes severe viral hemorrhagic fever in humans with case fatality rates ranging from 24% to 88%.   Rousettus aegypti, fruit bats of the Pteropodidae family, are considered to be natural hosts of Marburg virus. The Marburg virus is transmitted to people from fruit bats and spreads through human-to-human transmission.  No specific antiviral treatment or vaccine is available.

# Historical Perspective
Marburg hemorrhagic fever was first detected in 1967 in Marburg after which there has been reports of several sporadic outbreaks all over the world. Subsequently, outbreaks and sporadic cases were reported in Angola, Democratic Republic of the Congo, Kenya, South Africa, and Uganda

# Classification
There is no established system for the classification of Marburg hemorrhagic fever.

# Pathophysiology
Marburg virus is the causative agent of Marburg haemorrhagic fever (MHF). Initial human infection results from prolonged exposure to mines or caves inhabited by Rousettus bat colonies. After the Marburg virus initially transfers from animal host to human, mode of transmission is usually human-to-human and results from direct contact with bodily fluids of infected persons (blood, secretions) other contact fomites contaminated with infectious blood and tissues. Marburg virus primarily infects macrophages and dendritic cells. A cascade of events leads to Hypotension, metabolic disorders, immunosuppression and coagulopathy, finally resulting in multiorgan failure and shock.

# Causes
Marburg virus (/mrbr vars/ Template:Respell Template:Respell) is a hemorrhagic fever virus of the Filoviridae family of viruses and a member of the species Marburg marburgvirus, genus Marburgvirus. Marburg virus (MARV) causes Marburg virus disease in humans and nonhuman primates, a form of viral hemorrhagic fever. The virus is considered to be extremely dangerous. The WHO rates it as a risk group 4 pathogen (requiring biosafety level 4-equivalent containment). In the United States, the NIH/National Institute of Allergy and Infectious Diseases ranks it as a category A priority pathogen and the Centers for Disease Control and Prevention lists it as a category A bioterrorism agent. It is also is listed as a biological agent for export control by the Australia Group.
In 2009, expanded clinical trials of an Ebola and Marburg vaccine began in Kampala, Uganda.

# Differentiating Marburg hemorrhagic fever from Other Diseases
Marburg hemorrhagic fever must be differentiated from other viral hemorrhagic fevers that may cause fever, abdominal pain,and bleeding such as Ebola, Crimean-Congo hemorrhagic fever (CCHF), Hantavirus Infection, Rift Valley fever, Lujo hemorrhagic fever and Lassa fever. Because many of the signs and symptoms of Marburg hemorrhagic fever are similar to those of other infectious diseases such as malaria or typhoid fever, leptospirosis, Marburg hemorrhagic fever must also be differentiated from those infections.

# Epidemiology and Demographics
Recorded cases of Marburg hemorrhagic fever disease are rare. The first documented outbreak of marburg hemorrhagic fever occurred in 1967 in Marburg and Frankfurt, Germany and in Belgrade. Case fatality rates in marburg hemorrhagic fever outbreaks have ranged from 23% to 90%. Marburg hemorrhagic fever commonly affects younger individuals less than 5 years old and adults >50 years old compared to normal age groups.

# Risk Factors
Common risk factors in the development of Marburg hemorrhagic fever include close contact with African fruit bats, human patients, or non-human primates infected with Marburg virus. Less common risk factors in the development of Marburg hemorrhagic fever include occupations (people who handle non-human primates from Africa) and travellers to endemic areas.

# Screening
There is insufficient evidence to recommend routine screening for Marburg hemorrhagic fever.

# Natural History, Complications, and Prognosis
If left untreated symptoms of marburg hemorrhagic fever become increasingly severe and can include jaundice, inflammation of the pancreas, severe weight loss, delirium, shock, liver failure, massive hemorrhage, and multi-organ dysfunction. Common complications of marburg hemorrhagic fever include orchitis, Transverse myelitis and Parotitis. Prognosis of marburg hemorrhagic fever is generally poor. Case fatality rates in marburg hemorrhagic fever outbreaks have ranged from 23% to 90%.

# Diagnosis

## Diagnostic Criteria
The diagnosis of Marburg hemorrhagic fever relies primarily on the laboratory techniques such as reverse transcriptase PCR and ELISA-based antigen and antibody detection.

## History and Symptoms
Marburg hemorrhagic fever initially appears as a nonspecific febrile illness, which then rapidly progresses and leads to hemorrhagic complications and in severe cases may lead to a septic shock-like syndrome.

## Physical Examination
Marburg hemorrhagic fever is commonly associated with fever on physical examination at admission. At advanced stages of the disease, physical examination findings are more pertinent and often include unstable vital signs, such as tachycardia or relative bradycardia, orthostatic hypotension, and tachypnea. Physical examination may also be remarkable for abdominal tenderness and distension, evidence of mucosal or visceral bleeding, and neurological impairment.

## Laboratory Findings
Marburg virus infection may be confirmed by the laboratory techniques such as antibody-capture enzyme-linked immunosorbent assay, antigen-capture detection tests, serum neutralization test, reverse transcriptase polymerase chain reaction (RT-PCR), antigen detection tests and virus isolation by cell culture.

## Electrocardiogram
There are no ECG findings associated with marburg hemorrhagic fever.

## X-ray
There are no x-ray findings associated with Marburg hemorrhagic fever.

## Ultrasound
There are no echocardiography/ultrasound findings associated with Marburg hemorrhagic fever.

## CT scan
There are no CT scan findings associated with Marburg hemorrhagic fever.

## MRI
There are no MRI findings associated with Marburg hemorrhagic fever.

## Other Imaging Findings
There are no other imaging findings associated with Marburg hemorrhagic fever.

## Other Diagnostic Studies
There are no other diagnostic studies associated with Marburg hemorrhagic fever.

# Treatment

## Medical Therapy
There has been no approved treatment regimen yet for Marburg virus disease. However, few of the treatment modalities such as blood component therapy, immune therapy, and drug therapy are currently being evaluated. Supportive care such as rehydration with oral or intravenous fluids and maintenance of electrolyte balance, analgesics and symptomatic treatment may be beneficial.

## Surgery
Surgical intervention is not recommended for the management of Marburg hemorrhagic fever.

## Primary Prevention
No specific treatment or vaccine is yet available for Marburg hemorrhagic fever. Several vaccine candidates are being tested but it could be several years before any are available. New drug therapies have shown promising results in laboratory studies and are currently being evaluated. One way to protect against infection is avoiding fruit bats, and sick non-human primates in central Africa. Reducing the risk of infection to people include reducing the risk of bat-to-human transmission as well as human-to-human transmission, health education and, outbreak containment measures.

## Secondary Prevention
Effective measures for the secondary prevention of transmission Marburg hemorrhagic fever from person-to-person include barrier nursing techniques (wearing of protective gowns, gloves, and masks, placing the infected individual in strict isolation, sterilization or proper disposal of needles, equipment, and patient excretions).