Importantly, MARV is known to be able to persist in some survivors and to either reactivate and cause a secondary bout of MVD or to be transmitted via sperm, causing secondary cases of infection and disease.Of the 252 people who contracted Marburg during the 2004–2005 outbreak of a particularly virulent serotype in Angola, 227 died, for a case fatality rate of 90%. Although all age groups are susceptible to infection, children are rarely infected. In the 1998–2000 Congo epidemic, only 8% of the cases were children less than 5 years old. Epidemiology
Below is a table of outbreaks concerning MVD from 1967 to 2021:

1967 outbreak
MVD was first documented in 1967, when 31 people became ill in the German towns of Marburg and Frankfurt am Main, and in Belgrade, Yugoslavia. The outbreak involved 25 primary MARV infections and seven deaths, and six nonlethal secondary cases. The outbreak was traced to infected grivets (species Chlorocebus aethiops) imported from an undisclosed location in Uganda and used in developing poliomyelitis vaccines. The monkeys were received 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, was originally set up to develop sera against tetanus and diphtheria. Primary infections occurred in Behringwerke laboratory staff while working with grivet tissues or tissue cultures without adequate personal protective equipment. Secondary cases involved two physicians, a nurse, a post-mortem attendant, and the wife of a veterinarian.
All three initial cases (belonging to one family – two brothers and one sister) had died by 3 November. The fourth case – a health care worker – developed symptoms on 4 November and was admitted to a hospital. The first confirmed case traveled to Kenya before the death. A close contact of the second confirmed case traveled to Kampala. It is reported that several hundred people may have been exposed to infection. 2021 Guinean cases
In August 2021, two months after the re-emergent Ebola epidemic in the Guéckédou prefecture was declared over, a case of the Marburg disease was confirmed by health authorities through laboratory analysis. Other potential case of the disease in a contact awaits official results. These are the first cases of the Marburg hemorrhagic fever confirmed to happen in West Africa. The cases of Marburg also have been identified in Guéckédou. On August 10, the WHO said health authorities in Guinea have confirmed one death from Marburg virus. 2022 Ghanaian cases
In July 2022, preliminary analysis of samples taken from two patients – both deceased – in Ghana indicated the cases were positive for Marburg. However, per standard procedure, the samples were sent to the Pasteur Institute of Dakar for confirmation. On 17 July 2022 the two cases were confirmed by Ghana, which caused the country to declare a Marburg virus disease outbreak. An additional case was identified, bringing the total to three.