As I reported on May 24, 2010, the US Army Medical Research Institute of Infectious Diseases (USAMRIID) in conjunction with other agencies came up with a vaccine which produced immunity in monkeys against the Ebola virus.
This time USAMRIID has developed a vaccine that saved several monkeys given lethal doses of deadly Marburg virus between 24 to 48 hours after exposure.
According to Heinz Feldmann, chief of virology at the National Institute of Allergy and Infectious Diseases’ Rocky Mountain laboratories, “The results demonstrate that the vaccine can interfere with the Marburg infection and activate the immune system, both protecting the animal and preventing the virus from spreading.”
This is an improvement from USAMRIID’s announcement a few years ago where the vaccine could produce life-saving immunity if given within 30 minutes post-exposure. This was a great feat at the time; however according to Lisa Hensley, head of USARIID’s viral therapeutics branch, “it is almost impossible to get the drugs to a lab worker within 30 minutes of an accidental exposure to the virus, and it is altogether impossible to help people exposed to natural outbreaks within 30 minutes.”
It will surely be a long time until a vaccine like this is tested on a human, but some say this could be used in a lab emergency.
The Centers for Disease Control and Prevention (CDC) describes Marburg virus as follows: Marburg hemorrhagic fever is a rare, severe type of hemorrhagic fever which affects both humans and non-human primates. Caused by a genetically unique zoonotic (that is, animal-borne) RNA virus of the filovirus family, its recognition led to the creation of this virus family. The five species of Ebola virus are the only other known members of the filovirus family.
Recent scientific studies implicate the African fruit bat (Rousettus aegyptiacus) as the reservoir host of the Marburg virus. The African fruit bat is a sighted, cave-dwelling bat which is widely distributed across Africa. Fruit bats infected with Marburg virus do not to show obvious signs of illness. Primates, including humans, can become infected with Marburg virus, which can progress to serious disease with high mortality.
Just how the animal host first transmits Marburg virus to humans is unknown.
After an incubation period of 5-10 days, the onset of the disease is sudden and is marked by fever, chills, headache, and myalgia. Around the fifth day after the onset of symptoms, a maculopapular rash, most prominent on the trunk (chest, back, stomach), may occur. Nausea, vomiting, chest pain, a sore throat, abdominal pain, and diarrhea then may appear. Symptoms become increasingly severe and may include jaundice, inflammation of the pancreas, severe weight loss, delirium, shock, liver failure, massive hemorrhaging, and multi-organ dysfunction. The case-fatality rate for Marburg hemorrhagic fever is between 23-25%.
Confirmed cases of Marburg HF have been reported in Uganda, Zimbabwe, the Democratic Republic of the Congo, Kenya, and Angola. Cases of Marburg HF have occurred outside Africa, though infrequently.