Ghana announced the country’s first outbreak of Marburg virus disease after two people who were not related died on June 27 and 28. Word of a new outbreak of a lethal disease caused by viral infections added to the concerns of a public weary from battling the coronavirus pandemic, and recently alarmed by the spread of monkeypox and a new case of polio.

Doctors and public health experts in the country immediately started searching for anyone who had been exposed and investigating the cause of the spread in an effort to contain infection. For now, health researchers in Ghana and in other parts of the world said that there was no indication that the virus had spread further.

What is Marburg virus disease?

Marburg was first detected in 1967, when outbreaks of hemorrhagic fever occurred simultaneously in laboratories in Marburg and Frankfurt in Germany, and in Belgrade, in what is now Serbia — in cases that were linked to African green monkeys imported from Uganda. Other cases have since been found in Angola, the Democratic Republic of Congo, Kenya, South Africa and Uganda, according to the World Health Organization. Last month’s cases in Ghana were the first recorded in that country.

The Marburg virus is the pathogen that causes Marburg virus disease in humans, health experts said.

There are no vaccines or antiviral treatments for the disease, medical experts said, but hydrating patients and treating their specific symptoms can improve their chances of survival.

The disease is clinically similar to Ebola in its spread, symptoms and progression, although it is caused by a different virus, according to the W.H.O. In Marburg’s case, fruit bats are considered to be the hosts of the virus, though researchers say it does not cause them illness. Researchers believe that Ebola is likely carried by bats or by nonhuman primates, according to the Centers for Disease Control and Prevention. Even though it has not spread widely, Marburg has been deadly, with case fatality rates ranging from 24 to 88 percent, depending on which strain people contract and the management of cases, according to the W.H.O. The Ebola case fatality rates are nearly the same.

The Marburg virus can spread through direct contact with blood, secretions or other bodily fluids from infected people, according to the W.H.O. It can also spread through contact with contaminated surfaces and materials like bedding or clothing.

What are the symptoms of Marburg virus disease?

Marburg can cause severe viral hemorrhagic fever, which interferes with the blood’s ability to clot. The incubation period ranges from two to 21 days, and symptoms begin abruptly with high fever, severe headache and severe malaise, according to the W.H.O. Other symptoms can include muscle aches, diarrhea, nausea, lethargy and bleeding through vomit, feces and from other body parts.

“Mortality is very high,” said Dr. John Amuasi, who leads the global health and infectious disease research group at the Kumasi Center for Collaborative Research in Tropical Medicine in Kumasi, Ghana. “And there’s no asymptomatic Marburg.”

A patient can confirm their condition is Marburg through antibody, antigen and polymerase chain reaction tests, health organizations said.

How many cases have there been this year?

There have only been two cases of Marburg virus disease this year, both reported in Ghana. The people who contracted the virus were not related and they were in different parts of the Ashanti region of Ghana, Dr. Amuasi said. They both died.

Both patients were men who worked on farms, he said. One was a 26-year-old farmhand who had recently been to a different part of the country for work, and the other was a 56-year-old subsistence farmer. Contact tracing by local authorities led them to conclude that the men had not been in the same places.

Fruit bats, known to be the carriers of the virus, are common in the Ashanti region.

How does the outbreak compare to previous ones?

More than 200 people died in an outbreak in Angola from 2004 to 2005 and more than 100 died of the disease in the Democratic Republic of Congo from 1998 to 2000, according to the C.D.C. Other outbreaks of Marburg have not involved as many cases.

In 2021, there was one case in Guinea, which resulted in that person’s death, and three of four people who had the disease in Uganda in 2017 also died, according to the C.D.C.

Experts want to know how the two people contracted the virus in Ghana, said Dr. Francis Kasolo, the W.H.O. representative to the country.

“The current investigation is not only focusing on contacts,” Dr. Kasolo said. “We are also going back to medical records in these areas to see if there were unusual events in terms of cases that presented with symptoms. That is why we are holding back in saying that this is just a one-off event.”

Should we be worried?

The C.D.C.’s office in Ghana is working with local health authorities to assist with testing and epidemiological investigations, said Dr. Jonathan Towner, who leads the Virus Host Ecology Section at the C.D.C.

People in the United States are not at high risk for exposure, Dr. Towner said.

“It’s a very, very low risk probability at this point that there will be some travelers, for example, coming into the country with Marburg right now,” he said.

So far, Dr. Amuasi said, the public health response has been appropriate and transparent. Contacts of the two infected people were monitored, particularly in the 21 days after the two died.