The Middle East respiratory syndrome (MERS) virus has infected over 1,500 people around the world, one-third of whom have died. Previously, doctors relied on animal models to study the course of the virus, but research on the first human autopsy has finally been published, shedding light on how the disease attacks the human body.

According to the CDC, most MERS cases originate in the Arabian Peninsula, in countries including Saudi Arabia, United Arab Emirates (UAE), Qatar, Jordan, and Lebanon. The MERS coronavirus (MERS-CoV), was first identified in Saudi Arabia in 2012. Infected travelers, however, have made their way to the United Kingdom, France, the United States and Thailand, among others. While researchers still aren’t sure where MERS-CoV comes from, it’s possible that it started out in camels or other animals.

Now, with new information from the autopsy, scientists can better understand how the disease works and damages the body, starting first with the lungs.

“The long interval between the emergence of this dangerous disease three years ago and the first autopsy reminds us of the lost opportunity that the decline of the performance of autopsies, particularly research-oriented post-mortem examinations in the United States represents,” Dr. David Walker, Director of the University of Texas Medical Branch Center for Biodefense and Emerging Infectious Diseases, said in the press release.

Lungs

The autopsy was performed 10 hours after the death of a 45-year-old man who had fallen ill from the virus between April 2 and April 10, 2014 in the United Arab Emirates (UAE). Despite the fact that he reportedly had no contact with infected patients or camels, the man died quickly after the initial symptoms of fever, runny nose, and cough.

In the autopsy, the researchers discovered that the lungs were the most affected by the virus. It had damaged the air sacs and infected the bronchial submucosal glands in the lungs, which likely resulted in the human-to-human transmission, the authors explain.

Kidneys

And despite the fact that doctors previously believed that MERS attacks the kidneys, resulting in kidney failure, the researchers found no traces of MERS-CoV in the patient’s kidneys.

“This suggests that the acute renal failure in this patient was not caused by direct renal infection, but likely by other factors such as hypotension,” Dr. Sherif Zaki, Chief of the Infectious Diseases Pathology Branch at the Centers for Disease Control and Prevention, Atlanta, said in the press release. As a result, the researchers argue that doctors should focus therapies mainly on the lungs — which seem to be the primary source of infection and demise.

Heart And Circulation

In addition to damaged lungs, the researchers found that the MERS virus can result in several other chronic diseases in the organs — including severe peripheral vascular disease, which attacks the veins and arteries in the arms and legs, narrowing them and potentially causing blood clots in the circulatory system. They also saw signs of patchy cardiac fibrosis, which involves thickening of the heart valves, and hepatic steatosis, or fatty liver — but there were no signs that MERS affected the brain.

The autopsy is the first to offer a full picture of how MERS affects the human body, not just animals, the researchers note. Though there is no cure, scientists will now have better information to continue searching for therapies. Currently, treatment consists of simply alleviating symptoms.

Source: Ng D, Hosani F, Keating M, Gerber S, Jones T, Metcalfe M. Clinicopathologic, Immunohistochemical, and Ultrastructural Findings of a Fatal Case of Middle East Respiratory Syndrome Coronavirus Infection in United Arab Emirates, April 2014. The American Journal of Pathology, 2016.