Epidemiology
Most outbreaks of Marburg virus have occurred in Sub-Saharan Africa. Sporadic cases have also been reported in various parts of Europe and the United States. In 2008, for example, cases that occurred in the US and Netherlands were traced to people who had visited Sub-Saharan Africa. [8].
Healthcare workers treating victims of MARV and the family members of these victims are especially susceptible to contracting the virus. People working at diagnostic centers, veterinarians, and those working at quarantine facilities are also at increased risk. People who venture into caves or mines inhabited by fruit bats have an increased risk of contracting MARV, as do those who travel to countries where the disease is endemic [9].
The first MARV outbreak (discussed above) occurred when laboratory workers who were experimenting on African green monkeys that were imported from Uganda were infected from the animals they were working with [8]. During this initial outbreak, 31 people were diagnosed, and seven died. This led to a case-fatality rate of approximately 23%.
In 1975, three cases were reported in Johannesburg, South Africa. The first person admitted to a hospital with MVD was a man with a recent travel history to Zimbabwe. The man’s traveling companion and a nurse who cared for him at the hospital also contracted the infection. The man passed away, while the two women survived.
In 1980, Kenya reported two cases of MVD. The first patient had visited a cave in Kenya’s Mount Elgon National Park and was admitted to a hospital in Nairobi under specialized care. The patient died after developing severe complications. The doctor who attended to the patient developed symptoms nine days later. Fortunately, the physician recovered.
In 1987, Kenya reported a single MVD case that turned out to be fatal. It was a 15-year-old Danish teenager who presented with a recent history of headache, malaise, fever, and vomiting. Just like the cases from 1980, the teenager had visited a cave in Mount Elgon National Park. Despite all the care provided by the teenager’s healthcare team, he died on the 11th day of his illness. Three years later, in 1990, one case was reported in Russia. This case also resulted in a fatal outcome. It was the first MVD case ever reported in Russia [8].
The first massive MVD outbreak occurred between 1998 and 2000 in Durba, a village in the Haut-Uele Province of the Democratic Republic of Congo (DRC). Young men who worked at a gold mine near the town were the main victims. This outbreak resulted in 154 cases and 128 deaths (83% case-fatality rate) [2,8].
The second major MVD outbreak occurred between 2004 and 2005 in Angola. It began in Uige Province and became one of the deadliest MVD outbreaks the world has ever seen. Around 252 cases and 227 deaths were reported during this period. The case-fatality rate was almost 90%, one of the highest among all viral hemorrhagic fevers outbreaks in history.
Between 2007 and 2017, there were sporadic cases reported in Uganda. During the 2007 outbreak, four young men who worked at a lead and gold mine in Kamwenge District became ill. One patient died, but the remaining three survived.
In 2008, one person was diagnosed with MVD in the United States after visiting a cave in the Maramagambo Forest in Uganda. He developed an illness four days after returning to the US. He was treated at a hospital and recovered. A similar case occurred in the Netherlands in the same year from a 40-year-old Dutch woman who visited the same Ugandan cave mentioned above. The woman died on the tenth day of her illness.
In 2012, another significant outbreak occurred in Kabale, Ibanda, Mbarara, and Kampala in Uganda, with 15 cases and four fatalities. In 2014, one more case was reported in the Kampala district of Uganda, which turned out to be fatal. The last outbreak in this country occurred in 2017 in the Kween district in the eastern part of the country. Four cases were reported, and three turned out to be fatal.
In 2021, the Ministry of Health of the Republic of Guinea reported a case of MVD. The outcome was fatal. In this instance, MVD was not confirmed until after the patient died. Subsequently, contact tracing was performed by healthcare officials, and around 170 high-risk contacts were identified and monitored for three weeks. They all tested negative, and no more cases were reported in the country [8].
The most recent Marburg outbreak occurred on July 7, 2022 in the southern Ashanti region of Ghana. Two suspected cases were definitively identified on July 15, 2022. Two more suspected cases were reported on July 25, 2022. One turned out to be positive for MVD. As of January 2023, there were three reported MVD cases, out of which two died. Comprehensive contact tracing was carried out in different parts of the country [8, 10].