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Origin of MERS CoV

المؤلف:  Baijayantimala Mishra

المصدر:  Textbook of Medical Virology

الجزء والصفحة:  2nd Edition , p203

2025-11-10

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 It is thought that MERS CoV has originated from bats. Coronavirus related to MERS virus (group 2C CoV) has been isolated from several species of bats in Africa. Coronavirus that was isolated from bats in Middle East showed 100% sequence similarity with MERS CoV.

However, so far no human cases have shown direct or indirect epidemiological link with bats. This excludes the direct role of bat in MERS CoV transmission in humans.

Camels have now been proven as the intermediate animal reservoir. Several studies have shown MERS CoV serological infection in dromedary camels of the Middle East as well as in Africa from where the Middle East camels have originated. MERS virus has also been isolated from nasal samples of sick camels and viral RNA has been detected from nasal as well as rectal and fecal samples.

The 100% sequence similarities found in the virus that is isolated from a dromedary camel with that of the virus isolated from a patient who had close contact with a camel having upper respiratory tract infection.

The exact route of infection from camel to human is not known. Respiratory droplets are thought to be the most possible route. Ingestion of unpasteurized camel milk also can transmit the infection. Until now sustained man-to man transmission of MERS CoV is not seen. Usually the infection first comes from the infected camel to susceptible individual from whom other persons get the infection. Most of the man-to-man transmissions occur only up to secondary cases and very few tertiary cases (Fig. 1).

Fig1. Transmission of MERS virus