Nationals prospect Yewri Guillen, a shortstop who played and lived at the team’s baseball academy in the Dominican Republic, died Friday morning of bacterial meningitis. Guillen was 18.

“Definitely a big loss,” academy administrator Fausto Severino said. “We’re all shocked.”

The Nationals are still investigating the circumstances surrounding Guillen’s death. The Nationals have been in touch with other players who live and play at their complex in Boca Chica, Dominican Republic, and none reported any health concerns, Severino said.

“All those steps were taken care of and really there’s nothing else to do at this moment,” Nationals head team doctor Wiemi Douoguih said. “The medical staff down south, our trainers, our doctors jumped on it and have really exhausted every possible measure to make sure nothing spreads and that this doesn’t have any further implications.”

The Nationals’ complex has been closed since April 8, but only because the Nationals shutter their facility for several weeks every year in April. The plan for now is to re-open the facility April 25, as scheduled.

Guillen started feeling ill at the complex last week, Severino said, and at his request the Nationals sent him home days before they closed the facility as scheduled in order to see a doctor of his choice. During last weekend, after he visited a doctor, Guillen was hospitalized. He did Friday morning in the hospital.

“It’s really difficult to say” where Guillen contracted the disease, Douoguih said. “There’s bacterial particles that float around and sometimes somebody’s susceptible and you don’t know and they contract it and it’s very rapid. We all carry bacteria in our noses, in our mouths. It’s very possible that he got it from somebody who sneezed and he was susceptible and it was a very unfortunate thing.

“Obviously, a terrible tragedy but I’d like to really applaud the efforts of our medical training staff down south, who identified it and got him treatment as soon as possible. Unfortunately, even with the best treatment the mortality rate is about 20- to 30-percent so it’s really a very virulent and very terrible thing. And very unfortunate but fortunately, going forward, it is a very rare thing. And as unfortunate as it is, I think everything was done, I know everything was done to the letter by our medical and training staff to prevent any further catastrophe.”

The Nationals signed Guillen this February and planned for him to play for one of their minor league affiliates in the United States this summer, a sign of his advanced skill set.

“He was a young kid with a lot of future and had a lot of talent,” Severino said. “It’s a young life other than being a baseball player. He was a happy kid all the time. He was a great kid. He was upbeat. He was a kid from a humble family but with great spirits. He was a kid everybody liked.”

General Manager Mike Rizzo and other members of the Nationals front office called Guillen’s family to offer support. Before Friday’s game in the clubhouse, Nationals players collected money to be sent to Guillen’s family. On the field, the Nationals held a moment of silence for Guillen. In the Dominican Republic, a wake was held Friday night and the funeral will be Saturday.

“We feel terrible about it,” Rizzo said. “And it’s something that should never happen to anybody but specifically an 18-year-old person.”

The Nationals moved into their current base in the Dominican Republic, which they share with the Colorado Rockies, in May 2010. The new home, Complex De Las Americas, helped re-establish the Nationals’ presence on the talent-rich island following the scandal involving the prospect once known as Esmailyn Gonzalez.