MERS-CoV: Causes, Symptoms & Treatment

MERS corona virus (MERS-CoV ) is a member of the Coronaviridae family and was first identified in Saudi Arabia in 2012. The virus can dock onto human lung cells but is only weakly contagious from person to person. The course of disease after infection ranges from virtually asymptomatic to mild cold symptoms to fatal. A safe antiviral therapy does not (yet) exist. The virus has now spread to many other countries without having caused an epidemic or pandemic to date.

What is MERS-CoV infection?

MERS-CoV (Middle East respiratory syndrome coronavirus) is an RNA virus in the Coronaviridae family. The coronavirus has special protein structures on its surface that resemble tiny spikes. The spiky structures allow the MERS-CoV to dock to human lung cells. Infection occurs when the virus manages to enter the lung cell. By aligning the viral genome with the nucleotide sequences of known coronaviruses, it was found that MERS-CoV belongs to the genus Betacoronavirus and that its genome was previously unknown and unclassified. The virus was first identified in Saudi Arabia in 2012. On May 15, 2013, the virus was officially assigned the name MERS-CoV by the international commission responsible for it. Coronaviridae have the longest genomes within the RNA viruses, with over 30,000 nucleotides in some cases, indicating a high degree of genome stability and thus little susceptibility to mutation. This plays a major role in estimating whether and how quickly MERS-CoV can adapt to the new human host through mutations.

Causes

Corona virus MERS-CoV can be transmitted from person to person by the classical route of droplet and smear infection, but is considered only weakly contagious in persons with intact immune systems. According to the prevailing theory to date, bats on the Arabian Peninsula form the reservoir of origin of MERS-CoV. From the bats, the virus jumped to dromedaries, which are kept and bred as livestock in the Middle East. Research conducted in 2013 showed that in individual herds on the Arabian Peninsula, up to 74 percent of the animals produced antibodies to the virus. Dromedaries, which themselves show only mild symptoms after infection with MERS-CoV, form a large animal reservoir. The jump of the virus from dromedaries to humans can occur through droplet or smear infection in people who are in close contact with the animals. Another route of transmission could be through consumption of camel milk, which is very popular in the Arab region, if it is untreated, i.e., not pasteurized.

Symptoms, complaints, and signs

The incubation period after infection is usually less than a week, but can be as long as twelve days. Initial symptoms are similar to those of a viral cold, with cough, sputum, and fever. In people with a weakened or suppressed immune system, pneumonia with acute shortness of breath may develop around the second week. In severe courses, diarrhea occurs and renal insufficiencies have also been observed. According to statistics from the Saudi Health Authority as of June 01, 2015, a total of 1,150 laboratory-confirmed infections have been reported since September 2012, of which 427 have been fatal.

Diagnosis and disease progression

Initial suspicion of infection with MERS-CoV occurs in persons experiencing symptoms such as cough, fever, and respiratory distress after travel to high-risk areas or contact with infected persons. In the above cases, it should be diagnostically clarified whether a MERS-CoV infection is present. For direct detection of the MERS virus, the so-called polymerase chain reaction is used, in which the genetic material of the virus – if present in the sample – is amplified under laboratory conditions (in vitro) and certain nucleotide sequences can be compared with those of the MERS virus. Throat swabs or material from a tracheal lavage (bronchoalveolar lavage) serve as the starting material. Methods for detecting antibodies specific to MERS virus are limited.

Complications

In many cases, MERS-CoV may be diagnosed late because the incubation period of this disease is relatively long.Those affected suffer primarily from fever or a strong cough with sputum. Since the symptoms are usually very similar to the flu or a cold, they are often ignored. Furthermore, however, the disease also leads to shortness of breath, so that the patient feels tired. Pneumonia can also occur and significantly reduce the patient’s quality of life. It is not uncommon for kidney failure to occur without treatment, which can ultimately lead to the patient’s death if left untreated. Those affected are then dependent on dialysis or a kidney transplant. The breathing difficulties can also lead to a loss of consciousness, during which the affected person may possibly injure themselves by falling. The treatment of this disease is carried out with the help of antibiotics and usually leads to a positive course of the disease. There are no particular complications. Life expectancy is also not reduced if treatment is started early.

When should you go to the doctor?

If the affected person suffers from a persistent cough, sputum or a feeling of irritation in the throat, a doctor should be consulted. If there are disturbances in respiratory activity, shortness of breath sets in or the affected person suddenly wakes up during night sleep due to a lack of oxygen, he or she needs medical help. A doctor should be consulted in the event of anxiety, palpitations or a disturbance of the heart rhythm. Fever, pain or a dry feeling in the throat are other clues that should be followed up. If the irregularities continue unabated for several days or gradually increase in intensity, a physician is needed. If there are complaints of the intestinal tract, there is also cause for concern. A visit to the doctor is necessary as soon as there is diarrhea, pain in the abdomen or unusual bowel activity. Disturbances during urination are additional signs of a health impairment that must be monitored. If there is a reduced amount of urine, pain in the kidney region or discoloration of the urine, a visit to the doctor must be made. People living in Arab countries or returning from a stay there are particularly at risk. However, because MERS-CoV is a viral disease, people who have been in direct physical contact with people who have been in the region may also have the symptoms described.

Treatment and therapy

As of mid-2015, no proven antiviral therapy exists to directly combat MERS-CoV, so treatments are aimed at alleviating symptoms and strengthening the body’s immune system. It is important to maintain adequate hydration and avoid secondary bacterial infection, which can be minimized by administration of certain antibiotics. Several therapeutic options are discussed which may have an effect on reduced replication of the virus. Such an effect is hoped for from a combination of interferon-a2b and ribavirin. While the interferon serves to support the body’s own interferon synthesis, the ribavirin is a virostatic agent that is used for certain viral infections. An interesting theoretical approach that has already been successful in animal experiments involves the administration of immunoglobulins derived from the serum of infected dromedaries.

Prospect and prognosis

The infectious disease has a good prognosis in people with a basically stable immune system and no other previous illnesses. In some cases, a cure can also occur without initiating medical care. However, the prerequisite for this is that the affected person initiates self-help measures, has a healthy body’s own defense system, and uses alternative healing methods. It must be taken into account, however, that the healing path is usually prolonged if this course of action is chosen. Without a simultaneous sufficient rest and protection of the organism, an increase of the complaints is to be expected. In a drug therapy, the immune system is supported by the administration of certain active substances. The pathogen is thereby killed and subsequently transported out of the organism. Within a few days, a considerable improvement in the general state of health can already be documented. Recovery takes place within a few weeks.The prognosis worsens if the disease is diagnosed at a very late stage and other pre-existing conditions are present. The pathogen has already spread extensively and weakens the general health. Pneumonia may develop, potentially endangering the life of the affected person if left untreated. If respiratory disorders are present, additional deterioration of health can be expected. If complications occur, the affected person may also die prematurely.

Prevention

Preventive measures against infection for people staying in risk areas consist primarily of observing special hygiene rules and avoiding certain foods such as raw camel milk. The MERS virus can already be rendered harmless by washing hands and clothes and is not particularly contagious from person to person. For people who are in contact with infected persons, effective respirators of class FFP 2 or FFP 3 are additionally recommended to avoid infections through inhaled aerosols. It is helpful if the infected person can also wear a respirator. Several institutes are working internationally on the development of a vaccine for immunization. As of mid-2015, no effective vaccine exists yet.

Follow-up

In the case of a coronavirus infection caused by the MERS virus, there are usually no options for follow-up care available to the affected person. In this case, the patient is primarily dependent on early diagnosis to prevent further complications. The earlier the coronavirus infection is detected, the better the further course of treatment usually is. If left untreated, serious complications can develop. Strict bed rest and avoidance of excessive exertion or physical activity is advised to avoid unnecessary stress on the body. In some cases, the help or support of one’s family and friends is also very helpful in relieving the sufferer. However, contact with other people should be kept to a minimum during the acute aftercare phase to prevent infection. If there is no improvement as a result of taking the medication, it is advisable to consult a doctor immediately, as the coronavirus infection can also be fatal in the worst case. As a rule, however, the course is harmless. Affected persons need not fear a reduction in life expectancy.

What you can do yourself

In the case of MERS-CoV, some self-help options are available to the affected person. Care should still be taken to take antibiotics to prevent further infections and transmission to other people. When taking antibiotics, possible interactions with other medications should be considered, so regular consultation with a physician is advisable. The consumption of alcohol should be strictly avoided. Furthermore, the person affected by MERS-CoV should not engage in any strenuous activities and generally not put unnecessary strain on the body. Bed rest has a very positive effect on the course of the disease and can alleviate the symptoms. However, since the disease can also take a fatal course, it should always be treated by a physician, and hospitalization may be necessary. The cold-like symptoms can be alleviated with common household remedies. Throat tablets and teas help against cough and sore throat. The patient should make sure to take enough fluids, especially if MERS-CoV should cause diarrhea. In case of renal insufficiency, however, dialysis is necessary. If MERS-CoV leads to psychological discomfort, talking to close friends or family members will help.