Ebola: How concerned should you be?

The ongoing outbreak of Ebola virus, and the repatriation of two infected American healthcare workers, has raised many questions regarding spread of the virus into the population as well as the wisdom of bringing infected persons from Africa to the United States.

Ebola virus is a prime example of a hemorrhagic fever virus (a virus that has a high fatality rate and causes bleeding in affected individuals), which was first recognized in 1976 in Zaire, the Democratic Republic of the Congo. In this outbreak, there were over 300 cases of which almost 90 percent of affected persons died. The disease was spread by close physical contact by the use of contaminated needles and syringes in the hospital.

A similar outbreak occurred that year in Sudan, although mortality was significantly less. The first recognition of Ebola virus in the United States, in the late 1970s, was in Reston, Va., where the importation of infected monkeys led to a small number of human cases. This outbreak, which was popularized in the book “The Hot Zone,” did not spread outside the quarantine facility.

Over the next 15 years, there were multiple outbreaks of Ebola in Equatorial Africa. With the imposition of good isolation techniques, each of these outbreaks was contained and did not spread significantly.

In March 2014, an outbreak of Ebola occurred in West Africa. This virus has now spread to several adjoining countries including Guinea, Liberia, Sierra Leone and Nigeria. It is felt that inadequate quarantine measures and restrictions on travel have led to this spread. Inadequate infection control measures, including the use of gowns and gloves, have resulted in the infection and death of several healthcare workers.

Two American healthcare workers infected by Ebola have been transported back to the United States for care. While they were still in Africa, it is reported that they received an experimental antiserum directed against the virus. Present reports indicate that they appear to be recovering.

The transfer of these healthcare workers back to the United States has raised significant concerns about the risks of transmission of the disease to other persons and its spread into the general population. Several questions come up:

For a virus to spread efficiently, it must be released into the environment and make its way into a person’s body. A prime example of a highly infectious virus is the Varicella (Chickenpox) virus. A person contracts chickenpox by inhaling infectious virus from the air. Chickenpox virus will then slowly multiply within the infected person’s body.

Approximately two weeks later, the virus will be released back into the air from the “pox” or from the infected person’s lungs. Virtually all persons who are not immune to chickenpox will contract it when exposed. Prior to the introduction of a chickenpox vaccine, the occurrence of chickenpox in one child in a family led to all susceptible children contracting the disease. In my family’s case, all three of our children contracted chickenpox over a period of 2½ weeks.

Another example of a highly infectious virus is influenza, which is transmitted via the respiratory (lungs) route. Each year, In the United States, influenza is responsible for extensive outbreaks. The present strains of influenza circulating during winter outbreaks are associated with some deaths but usually only among the frail and the elderly. Avian influenza, which is associated with a much more significant death rate, spreads poorly between people.

The outbreak of SARS (Severe Acute Respiratory Syndrome) in 2003 was an example of a highly infectious virus which spread around the world via air travel. The initial cases occurred in Guangdong province, China, where it was felt that people acquired it from animals in open air markets. A doctor who treated infected patients traveled to Hong King to attend a wedding and fell ill. Persons who were exposed to him at his hotel, or to his contacts, traveled to Taipei, Hanoi, Thailand and Singapore, initiating outbreaks at each of these locations. A Canadian staying at the hotel returned to Canada, leading to illness in 400 persons and 44 deaths. Twenty-five thousand people were quarantined in an ultimately successful effort to contain the disease.

We have all heard of the outbreaks of Norovirus diarrhea on cruise ships. Norovirus is a highly infectious virus that causes nausea, vomiting and diarrhea and is acquired through the ingestion of the virus through the mouth. Contamination of solid surfaces can lead to a long-lasting risk of infection. Extensive cleaning with bleach and similar agents is necessary for control and has resulted in cruise ships being taken out of service for intensive cleaning.

HIV can lead to progressive deterioration in a patient’s immunity. After a period of several years, HIV infected patients become susceptible to infections not seen in healthy persons. In the early years of the AIDS epidemic, a lack of knowledge of how HIV was transmitted led to affected persons being ostracized. I recall how food workers left the meal trays of those patients outside their rooms because of fear of becoming infected. It is now known that HIV is transmitted through blood and body fluids by either intimate contact or direct injection/contamination with infected blood.

Infected blood is not usually dangerous to someone with intact skin but a blood splash into the eye or into a break in the skin can lead to infection. As such, prevention of the spread of HIV can be attained by preventing this direct spread. You cannot get HIV by sitting near an infected patient.

Ebola, as noted by the Centers for Disease Control, is a hemorrhagic fever virus. Symptoms include fever, headache, joint and muscle aches, weakness, diarrhea, vomiting, stomach pain, lack of appetite and, eventually, abnormal bleeding. Ebola may not be transmitted through the air or through contaminated food or water. It is transmitted through direct contact with blood or body fluids from infected persons. In a way, transmission is very similar to HIV although the course of Ebola is much more explosive and has a much higher short-term death rate. Persons who are infected but not yet showing any symptoms of disease are not contagious.

The rapid and extensive spread of Ebola into the African population is a result of both cultural practices and lack of resources. Persons who died of Ebola were frequently brought back to their native villages. In preparation for burial, they were cleansed both externally and internally. This led to the contamination of many people with blood and body fluids from this cleaning. In many hospitals in Africa, resources are scarce and medical equipment, including needles and syringes, are reused. If sterilization is inadequate, the equipment itself may lead to further transmission. Adding to these problems is the inadequate use of protective clothing such as impermeable gown, gloves and face mask.

As reported in the New York Times on Aug. 6, several cases have been reported where family members have entered clinics and “snatched” relatives and have not abided by quarantine rules. The director of communications of the president of Sierra Leone noted that “family members have forced their way into these medical facilities and removed” patients “and taking them home, and overpowered the workers.” This disregard of governmentally imposed quarantine regulations has contributed to the spread of the disease into families. Sierra Leone troops and police officers have been deployed to ensure that these infected persons remain isolated.

The repatriation of the two Americans infected with Ebola has raised valid concerns about the risk of an unknown infected person traveling by air to the United States. There have been multiple reports of possible cases at regional medical centers. On Aug. 5, it was announced that there was a ”possible” case of Ebola being evaluated at the Ohio State University Hospital. Ebola was suspected because of illness in a traveler who had returned from West Africa. In this case, as in all others around the country, Ebola infection was not confirmed. No Americans have been confirmed as being infected with Ebola other than the two hospitalized in Atlanta.

The Centers for Disease Control has issued a case definition for persons with suspected Ebola virus infection. This states that one may consider a person to be possibly infected if there is an:

Illness in a person who has both consistent symptoms and risk factors as follows: 1) Clinical criteria, which includes fever of greater than 38.6 degrees Celsius or 101.5 degrees Fahrenheit, and additional symptoms such as severe headache, muscle pain, vomiting, diarrhea, abdominal pain, or unexplained hemorrhage; AND 2) Epidemiologic risk factors within the past three weeks before the onset of symptoms, such as contact with blood or other body fluids of a patient known to have or suspected to have Ebola virus disease (EVD); residence in — or travel to — an area where EVD transmission is active; or direct handling of bats, rodents, or primates from disease-endemic areas. Malaria diagnostics should also be a part of initial testing because it is a common cause of febrile illness in persons with a travel history to the affected countries.

Persons who have met these criteria and have presented to Emergency Departments around the country are those who have been tested for Ebola.

The two patients who are presently in Atlanta are being treated in a state-of-the-art isolation facility that was specifically designed to house and treat patients with highly infectious diseases. This facility is where several SARS patients were treated over 10 years ago. The facility is physically separate from the main hospital. The rooms in which the patients are being treated are under negative pressure, which means that air enters the room but cannot exit through the door; all air leaving the room is filtered through “HEPA” filters, which can remove particles as small as viruses. Anyone entering the room will be wearing an impermeable gown, gloves, shoe coverings, hood, and a protective face mask. When leaving the room, these garments will be discarded and sterilized or incinerated. The patients will be able to see relatives through a plate-glass window and will communicate via an intercom or telephone. No one other than appropriately protected health care personnel will be allowed to come into contact with the patients.

Until recently, the primary treatment for Ebola infection was supportive. Patients would receive intravenous fluids, blood products and might be placed on a respirator or dialysis machine if the need arose. News reports have revealed that both Americans who were infected with Ebola received an experimental treatment for Ebola. This medication, ZMapp, was produced by Mapp Biopharmaceuticals Inc. with funding provided by the National Institutes of Health, the Department of Defense and the Department of Health and Human Services’ Biomedical Advanced Research and Development Authority.

ZMapp is not a vaccine but an antiserum designed to treat persons with Ebola, not to prevent it. It has only been tested in monkeys and has not entered human testing yet. Mapp acts in a way similar to Rabies Immune Globulin, an antiserum given to patients who are suspected of being infected by a rabid animal. In the case of Rabies Immune Globulin, the earlier you treat an infected person in conjunction with vaccination, the better your chances of preventing rabies. It is too early to say whether ZMapp will be adopted as an effective agent against Ebola. It must still undergo more extensive testing to assure us that it is both safe and effective.

In summary, Ebola has once again made front page headlines and has been responsible for deaths in Africa. The epidemic has spread not due to the highly infectious nature of the virus but due to poor adherence to isolation and critical infection control measures. The likelihood that this virus could establish a “beachhead” in this country is extremely low and transmission is only by contamination with infectious blood or bodily fluids. Supportive care remains a mainstay of treatment but new antisera, antiviral agents and vaccines are under development which may help to eliminate this threat.

— JACK M. BERNSTEIN, M.D.

Jack M. Bernstein, M.D., is a professor of Medicine and Pathology at Wright State University and the coordinator for Research and Development at the Dayton Veterans Affairs Medical Center. He is a Fellow of the American College of Physicians and the Infectious Diseases Society of America, and has special interests in viral diseases and antiviral chemotherapy.