It is unknown how Marburg virus first spreads from its animal host to people; however, for the 2 cases in tourists visiting Uganda in 2008, unprotected contact with infected bat feces or aerosols are the most likely routes of infection.
After this initial crossover of virus from host animal to people, transmission occurs through person-to-person contact. The virus spreads through direct contact (such as through broken skin or mucous membranes in the eyes, nose, or mouth) with:
- Blood or body fluids* (urine, saliva, sweat, feces, vomit, breast milk, amniotic fluid, and semen) of a person who is sick with or died from Marburg virus disease, or
- Objects contaminated with body fluids from a person who is sick with or has died from Marburg virus disease (such as clothes, bedding, needles, and medical equipment).
- Semen from a man who recovered from MVD (through oral, vaginal, or anal sex). The virus can remain in certain body fluids (including semen) of a patient who has recovered from MVD, even if they no longer have symptoms of severe illness. There is no evidence that Marburg virus can spread through sex or other contact with vaginal fluids from a woman who has had MVD.
Spread of the virus between people has occurred in close environments and among direct contacts. A common example is through caregivers in the home or in a hospital (nosocomial transmission).
In previous outbreaks, people who have handled infected non-human primates or have come in direct contact with their body fluids have become infected with Marburg virus. Laboratory exposures can also occur when lab staff handle live Marburg virus.
*Data on Marburg virus is limited. However, as Marburg virus is in the same family as the virus that causes Ebola virus disease, it can be assumed that virus persistence in body fluids may be similar.