The unidentified Illinois man had “extended face-to-face contact” during a 40-minute business meeting with an Indiana man who was diagnosed with MERS after traveling from Saudi Arabia, Dr. David Swerdlow told reporters during a telephone briefing.
A blood test confirmed the Illinois man had been previously infected, and he reported suffering only mild cold-like symptoms and did not seek or require medical care, Swerdlow said.
“We think that this patient was likely infected with MERS. But technically he doesn’t count as an official case of MERS,” he said.
The case does not meet the World Health Organization definition of an active case, which requires evidence of a live virus, according to Swordlow.
Even so, U.S. health officials appear to be treating it as one.
The case was discovered as part of an investigation by U.S. health officials to track people who came in close contact with the Indiana man, who became the first person diagnosed with MERS in the United States. He was diagnosed with the virus on May 2.
MERS, first found in the Arabian Peninsula in 2012, is a coronavirus — the same group of viruses as the common cold. It attacks the respiratory system.
Symptoms, which include fever and a cough, are severe and can lead to pneumonia and kidney failure.
Gastrointestinal symptoms such as diarrhea have also been seen, according to the WHO. There is no vaccine or special treatment, and it can be fatal in up to one-third of cases, Dr. Anne Schuchat, assistant surgeon general for the U.S. Public Health Service told recently.
To date, there have been more than 570 confirmed cases of MERS, including 171 deaths, according to the World Health Organization. The number of countries with confirmed cases expanded to 18, with a case in the Netherlands, according to the WHO.
Many of the cases are in Saudi Arabia and the United Arab Emirates.
No one knows exactly how the virus originated, but evidence implicating camels is emerging. In a recently published study in mBio, researchers said they isolated live MERS virus from two single-humped camels, known as dromedaries. They found multiple substrains in the camel viruses, including one that perfectly matches a substrain isolated from a human patient.