Marburg virus

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The Marburg virus is the causative agent of Marburg haemorrhagic fever. Both the disease and virus are related to Ebola and originate in the same part of Africa (Uganda and western Kenya). Its source is a zoonosis of unknown origin.

The disease is spread through bodily fluids, including blood, excrement, saliva, and vomit. There is no cure or vaccine for this deadly and infectious virus. Victims suffer a high fever, diarrhea, vomiting, and severe bleeding from bodily orifices and usually die within a week. Fatality rates range from 25 to 100 percent.

The virus is also called the Angola virus after the outbreak in that country. Beginning in October 2004 and continuing into 2005, the outbreak is the world's worst epidemic of any kind of haemorrhagic fever and is killing increasing numbers of people rather than abating. [1] Through 2005, the number of cases has increased by roughly 3% per day. The mortality rate for this outbreak has remained above 99%. "For the first four months of the outbreak (Oct 2004 - January 2005), there were 34 cases and 34 deaths for a case fatality rate of 100%." Recombinomics News quoting this Red Cross media release

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The Marburg virus

The viral structure is typical of filoviruses, with long threadlike particles which have a consistent diameter but vary greatly in length from an average of 800 nanometres up to 14,000 nm, with peak infectious activity at about 790 nm. Virions (viral particles) contain seven known structural proteins. While nearly identical to Ebola virus in structure, Marburg virus is antigenically distinct from Ebola virus � in other words, it triggers different antibodies in infected organisms. It was the first filovirus to be identified.

Infection details

Because many of the signs and symptoms of Marburg hemorrhagic fever are similar to those of other infectious diseases, such as malaria or typhoid, diagnosis of the disease can be difficult, especially if only a single case is involved.

The disease is characterised by the sudden onset of fever, headache, and muscle pain after an incubation period of 3-9 days. Within a week, a maculopapular rash develops, followed by vomiting, chest and abdominal pain, and diarrhea. The disease can then become increasingly damaging, causing jaundice, delirium, liver failure, and extensive hemorrhage. Recovery from the disease is prolonged and can be marked by orchitis, recurrent hepatitis, transverse myelitis or uveitis, or inflammation of the spinal cord, eyes, or parotid gland. Depending upon health care and hospitalization support, the disease can have very high fatality rates, with estimates ranging from 25 percent up to 100 percent. [2] [3]

Infection is believed to be spread by close contact with body fluids of those infected, and the virus is unlikely to spread through casual contact. Patients are most contagious during the acute phase of the illness. Unsafe burial practices represent another infection vector.

A few research groups are working on drugs and vaccines to fight the virus. In 2004, a group in the United States showed that inactive virus particles injected into guinea pigs protected them from infection.

Marburg virus history

Early outbreaks

This virus was first documented in 1967, when 31 people became ill in the German town of Marburg, after which it is named, as well as in Frankfurt am Main and the then Yugoslavian city of Belgrade. The outbreak involved 25 primary infections, with 7 deaths, and 6 secondary cases, with no deaths. The primary infections were in laboratory staff exposed to the Marburg virus while working with monkeys or their tissues. The secondary cases involved two doctors, a nurse, a post-mortem attendant, and the wife of a veterinarian. All secondary cases had direct contact, usually involving blood, with a primary case. Both doctors became infected through accidental skin pricks when drawing blood from patients.

The outbreak was traced to infected African grivets of the species Cercopithecus aethiops taken from Uganda and used in developing polio vaccines. The monkeys were imported by Behringwerke, a Marburg company founded by the first winner of the Nobel Prize in Medicine, Emil von Behring. The company, which at the time was owned by Hoechst and is now part of Dade Behring, was originally set up to develop serums against tetanus and diphtheria.

In 1975, three people in South Africa were infected by the Marburg virus by a man returning from Zimbabwe, resulting in only one death. There were similar cases in 1980 and 1987 in Kenya. The next major outbreak occured in the Democratic Republic of Congo from 1998 to 2000, where 123 of 149 cases were fatal. This outbreak originated from miners in Durba and Watsa in Orientale, Congo.

2004-2005 outbreak in Angola

In early 2005, the World Health Organization began investigating an outbreak of a then-undiagnosed hemorrhagic fever in Angola, which was centered around the northeastern Uige Province. The outbreak was believed to have begun towards the end of 2004. On March 22, 2005, as the death toll neared 100, the cause of the illness was identified as the Marburg virus. By April 11, 2005, Angola's health department reported it had spread to 7 of 18 provinces and 203 of 221 known cases had been fatal.

Weekly Reported Deaths
WHO Report Date Cumulative Deaths Deaths During Prior Week
3/23/2005 95
3/29/2005 117 22
4/4/2005 150 33
4/11/2005 194 44

According to the World Health Organization, 80 percent of the deaths in Angola have been children under the age of 15, but the virus has also started to claim adult victims, including six nurses and two foreign doctors. There has been speculation that the high death rate among children in the early stages of this outbreak may simply be due to an early, undiagnosed case appearing at the children's ward of the Uige hospital.

Countries with direct air links, such as Portugal, have begun screening passengers arriving from Angola. The Angolan government has asked for international assistance, pointing out that there are only about 1,200 doctors in the entire country, with some provinces having as few as two. [[M�decins Sans Fronti�res]] (MSF) reported that when their team arrived at the provincial hospital at the centre of the outbreak, they found it operating without water and electricity. Contact tracing is complicated by the fact that the country's roads and other infrastructure has been devastated after decades of civil war and the countryside remains littered with land mines.

Meanwhile, at Americo Boa Vida Hospital in the capital, Luanda, a team of international experts prepared a special isolation ward to handle cases from the countryside. The ward can accommodate up to 40 patients, but there has been growing resistance to medical treatment. Because the disease has almost invariably resulted in death, some people have come to view hospitals and medical workers with suspicion and there have been incidents of medical teams being attacked in the countryside. [4]

External links

References

[[fr:Fi�vre h�morragique de Marburg]]


References

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