These are the ways doctors think coronavirus can attack the body

Since the first cases of COVID-19 emerged at the end of 2019, the ensuing pandemic is confirmed to have infected more than 3 million people, taken hundreds of thousands of lives and brought many of the world’s economies to a virtual standstill. Yet comparatively little is known about the disease and how it spreads through the human body.

For many people the virus causes a mild illness, but in some cases the effects can be more severe, if not life threatening.

More than 1 million people have recovered from the disease – but the COVID-19 threat is far from over.

Different strains of coronavirus may share common traits, but each pathogen is unique and follows its own course. Scientists around the world are studying COVID-19 to better understand how it impacts the body, in a bid to treat people with the disease.

Like other known respiratory diseases, COVID-19 primarily affects the lungs and can cause life-threatening complications such as pneumonia, sepsis or lung failure. But evidence is emerging that it can attack in other places too – here are some of the parts of the body doctors think can also be affected.

Heart

A study of more than 400 hospitalized cases of COVID-19 in the original outbreak in Wuhan, China, found almost one fifth of patients suffered cardiac injuries from the disease, leading to a higher risk of mortality.

Why the virus causes heart damage is unclear. Writing in the journal Science, Meredith Wadman and colleagues suggest the disease could directly impact the lining of the heart and blood vessels, or blood vessels could be damaged by lack of oxygen caused by trauma in the lungs.

“The virus acts like no pathogen humanity has ever seen,” they say.

Blood

If blood vessels are a target for the disease, it could help explain why patients with high blood pressure are at greater risk. A survey of patients hospitalized with confirmed COVID-19 cases in 14 US states found more than half had pre-existing blood hypertension conditions.

A study published in Thrombosis Research found blood clots occur in a high proportion of hospital patients receiving intensive care. Clots can migrate through the bloodstream, sometimes with deadly consequences.

Brain and nervous system

Some studies report that the disease can adversely affect the brain. More than a third of 214 hospital patients with coronavirus in the Wuhan study developed symptoms such as losing their sense of smell, taste or vision. The findings indicate the virus might infect nerve endings within the brain.

Neurological conditions like seizures, strokes, damaged vision and muscle injuries were found to be more common in patients with severe COVID-19 infections.

The digestive tract

Research also suggests the virus can reach the human digestive system. The findings of a study published in the medical journal Gastroenterology revealed traces of COVID-19 in the stool samples of 39 of 73 patients hospitalized with the disease.

“Recent reports suggest up to half of patients, averaging about 20% across studies, experience diarrhea,” Brennan Spiegel of Cedars-Sinai Medical Center in Los Angeles, told Science, indicating the impact of the disease on the digestive tract.

These are just some of the ways COVID-19 can impact the body, but there are others. With controlled studies on many aspects of the disease still at the early stages, there is hope that future research will find ways to combat the threat.