Middle East Respiratory Syndrome (MERS-CoV)

Middle East Respiratory Syndrome (MERS-CoV)

Symptoms

MERS-CoV infection can manifest along a wide clinical spectrum, ranging from no symptoms (asymptomatic) or mild respiratory symptoms to severe acute respiratory disease and mortality. Common symptoms of MERS-CoV disease include fever, cough, and shortness of breath. While pneumonia is frequently observed, it is not always present.

Gastrointestinal symptoms, such as diarrhea, have also been noted. Severe cases can progress to respiratory failure necessitating mechanical ventilation and intensive care support. The virus tends to induce more severe illness in older individuals, those with compromised immune systems, and individuals with chronic conditions like renal disease, cancer, chronic lung disease, and diabetes.

Approximately 35% of MERS patients have succumbed to the disease, though this figure may not accurately reflect the true mortality rate, as mild cases may go undetected by current surveillance systems. Until more data is available, mortality rates are primarily calculated based on laboratory-confirmed cases.

Source of the Virus

MERS-CoV is a zoonotic virus, meaning it is transmitted between animals and humans. Research indicates that humans contract the virus through direct or indirect exposure to infected dromedary camels. The virus has been detected in dromedaries across various countries in the Middle East, Africa, and South Asia.

While the exact origins of the virus remain unclear, genetic analyses suggest that it may have originated in bats and later transmitted to camels.

Transmission

Animal-to-Human Transmission: The precise mode of transmission from animals to humans is not fully elucidated, but dromedary camels serve as the primary reservoir host for MERS-CoV and a source of infection in humans. Identical strains of MERS-CoV found in humans have been isolated from dromedaries in countries such as Egypt, Oman, Qatar, and Saudi Arabia.

Human-to-Human Transmission: The virus does not readily spread from person to person unless there is close contact, such as providing unprotected care to an infected individual. Instances of human-to-human transmission have been observed in clusters, particularly in healthcare settings with inadequate infection prevention and control measures. Although most MERS cases have occurred in healthcare settings, sustained human-to-human transmission has not been documented globally.

Prevention and Treatment

Currently, there is no vaccine or specific treatment available for MERS-CoV infection, although several vaccines and treatments are under development. Supportive care tailored to the patient's clinical condition forms the basis of treatment.

As a precautionary measure, individuals visiting areas where dromedary camels and other animals are present should adhere to general hygiene practices, including regular handwashing before and after interacting with animals. Avoiding contact with sick animals is advisable.

Consumption of raw or undercooked animal products, including milk and meat, poses a high risk of infection from various pathogens. Proper cooking or pasteurization ensures the safety of animal products, although they should be handled with care to prevent cross-contamination.

Individuals with conditions such as diabetes, renal failure, chronic lung disease, and compromised immune systems are considered at high risk of severe MERS-CoV infection. These individuals should refrain from contact with camels, consumption of raw camel products, or undercooked meat.