Outbreak of a new disease: Marburg virus – is it worth it to be afraid

In 2021, another outbreak of the Marburg virus epidemic was detected in Guinea. Then hundreds of people died from the disease. There have been two deaths in Ghana this year, and almost a hundred people have been quarantined. ^[1]. Cases of infection have been seen in Uganda, Zimbabwe, Congo, Kenya. The world community is concerned about the potential threat of a new epidemic of the virus, so it is worthwhile to figure out what kind of disease it is and how dangerous it is for humanity.

Main features of Marburg hemorrhagic fever

The Marburg virus is a relative of the Ebola virus and therefore belongs to the filovirus family. These two microorganisms cause different diseases, but the clinical picture of both is very similar. The main concern is the fact that the lethality of Marburg hemorrhagic fever reaches 88%.

Primary human infection occurs through contact with the African bat Rousettus aegyptiacus, and this is confirmed by identified cases of the disease. The sick were in caves and mines – the natural habitat of such animals. Interestingly, the infected bats themselves do not show any signs of hemorrhagic fever, they are asymptomatic. But in primates, the course of the disease is partly similar to the clinical picture in humans, and the mortality rate is also high. ^[2]

After infection, bats become carriers, and the virus is contained in their physiological fluids – saliva, urine. It is believed that it is upon contact with them, as well as animal feces, that it enters the human body. Further, the viral infection begins to spread among the human population, because the patient can infect others until his full recovery. The main route of transmission of the Marburg virus is contact with an infected person, since the microorganism persists:

• in particles of saliva, urine, sweat, feces, amniotic fluid, breast milk or vomit;
• on objects with which the patient came into contact – clothes, bed linen. This explains the high probability of infection with the virus during funeral ceremonies, which are common on the African continent. During the funeral, there is direct contact with the body and clothing of the deceased;
• in the semen of a man who had Marburg hemorrhagic fever. In this case, the route of transmission would be vaginal, oral, or anal sex. But there is no confirmation that it is possible to get infected from a sick woman through sexual contact;
• on medical equipment used for diagnosis and treatment. There are frequent cases of infection of medical workers who conducted examinations and provided care to patients, both with a confirmed diagnosis, and only with suspicion of Marburg hemorrhagic fever. The reason for this is insufficient compliance with control and preventive measures when in contact with an infected person. ^[3]

Clinical picture of Marburg virus infection

After infection and before the first symptoms appear, it can take from 2 to 21 days. During the incubation period, a person can infect others, even without being aware of the presence of the Marburg virus in his body. And it quickly begins to affect the liver, gastrointestinal tract, and central nervous system.

Symptoms of the disease occur suddenly and, as a rule, immediately manifest themselves as a rather severe form. A patient with Marburg hemorrhagic fever feels:

• severe malaise;
• severe headache and muscle pain;
• a sharp increase in body temperature to critical levels.

This clinical picture is typical for the first days of the disease. On the third day, nausea, vomiting, cramps and abdominal pain are added to the symptoms. There may also be diarrhea that lasts 5-7 days. During the first 10 days of the disease, a strong depletion of the body occurs, so apathy is felt, and the infected person takes on a haggard appearance with sunken eyes and a lack of emotions. It is noted that some patients experience a rash. But these are only isolated cases, and interestingly, such skin lesions do not itch.

The second week of the disease is characterized by the appearance of hemorrhagic symptoms. Blood can be observed in vomit, feces. Also, bleeding from the vagina in women, gums, and nose often occurs. The most problematic is that blood also appears at the sites of vein puncture for intravenous administration of drugs or taking material for analysis. This complicates further treatment and diagnosis of the patient’s condition. All this time, the body temperature can stay high, and the central nervous system is also affected, which manifests itself:

• aggression against others;
• severe irritability;
• confusion of consciousness. ^[4]

During such periods, doctors and medical staff should strictly observe preventive measures so as not to become infected with the virus.

The lethal outcome of the disease is 27-88%, therefore, on the 8-9th day after the onset of the first symptoms, the patient may die due to severe blood loss and shock. Timely initiation of treatment increases the chances of survival.

How is Marburg hemorrhagic fever diagnosed?

The clinical picture of the disease caused by the Marburg virus is somewhat similar to Ebola, meningitis, malaria, typhoid fever, so differential diagnosis is required. Several methods are used to confirm the diagnosis:

1. Immunoenzymatic analysis of blood to detect antibodies in it.
2. General and biochemical blood test.
3. Analysis for liver tests.
4. Urinalysis, as well as the determination of blood coagulation.
5. Electron microscopy of affected organs to identify specific virions.
6. Reverse transcriptase polymerase chain reaction method.

All laboratory analyzes are performed under high biosecurity conditions, as materials from an infected person, upon contact, can cause infection of medical workers or laboratory specialists ^[5].

Can Marburg virus infection be cured?

At the moment, there are no vaccines and specific treatment aimed specifically at the virus itself. True, there are suggestions that monoclonal antibodies and antiviral agents (remdesivir and fapiravir) that have passed clinical trials for the treatment of Ebola can be used in the treatment of the disease. But for now, this method is ready to be used only as an experiment.

Therapy for Marburg hemorrhagic fever today includes:

1. Supportive care including:
   • restoration of water and electrolyte balance;
   • maintenance of circulating blood volume;
   • elimination of symptoms, including pain relief and antibiotic therapy;
   • minimization of invasive procedures due to the possibility of bleeding.
2. Antiviral treatment.

Patients infected with the Marburg virus must be treated in a hospital without fail in compliance with safety conditions. The disease is very contagious, so it is not so difficult to get infected. Despite the fact that the mortality rate is quite high – in African countries up to 88%, on other continents – 27-55%, there are positive forecasts. It is important to start treatment in time to prevent complications.

It gives hope that in 2020, clinical trials of vaccines against Ebola hemorrhagic fever, which is caused by a virus from the same family as Marburg, have begun. If their effectiveness is fully confirmed, it can also be used against Marburg.

Where it all started

Egyptian bats are believed to be the main carrier of the disease. But the history of the emergence of the virus is associated with completely different animals – African green monkeys from Uganda.

In 1967, in the laboratories of Frankfurt, Marburg and Belgrade, scientists worked with the tissues of these animals. Then they fell ill with an unknown infection and infected the doctors who cared for them. This is how MAV, the Marburg virus, was discovered, named after the location of one of the laboratories. ^[6]. Nine people out of 37 infected have died.

Since 1967, about 600 cases of outbreaks of Marburg hemorrhagic fever have been registered in Uganda, the Republic of the Congo, and Angola. In the CIS countries, only 1 case was recorded in 1990. Infection occurred as a result of contact with an archived infected sample. Europe encountered the Marburg virus in 2008 in Holland. A patient with confirmed hemorrhagic fever returned from Uganda, where she spent her vacation ^[7].

What are the forecasts

So far, MAV has not been seen outside the African continent. But given that African countries are of interest to many tourists, the spread of the epidemic is possible. WHO is concerned about this threat, therefore, has developed a number of recommendations and preventive measures that could stop the viral infection:

• reduce the possibility of staying in mines and caves where bats live. Ensure the use of protective gloves, masks, clothing that completely covers the body during tourism or scientific research in such places;
• disseminate information to the public at potential outbreak sites. Thermally process meat, including domestic animals, in the regions of the spread of the epidemic;
• quick burial of those who died of fever without ceremonies, which can cause infection of relatives and participants in the funeral;
• use gloves, a mask and other protective equipment when caring for patients;
• use condoms during intercourse for men who have had the disease before receiving two negative tests;
• quarantine of those who may be potentially ill to avoid the spread of a viral infection ^[2].

Those who may have potential contact with sick or infected animals are more likely to get sick. That is why the first thing everyone can do is to avoid such an opportunity by choosing for tourism not those countries in Africa where outbreaks of the epidemic have been recorded.

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