It is important to get your quotes straight. I believe this is actually from the newspaper The Guardian and is actually a quote plus a paraphrase of the words of Margaret Chan, the director of WHO [World Health Organization], words that she spoke at an emergency meeting:
It was "deeply concerning" that the virus had now been detected in 23 countries in the Americas, she added.
This is report of past speech. We can tell because "added" is past tense. We may infer that Ms. Chan said at the time of the meeting:
"It is deeply concerning that the virus has now been detected in 23 countries in the Americas."
When the newspaper reports on this meeting after it happened, the tenses must be transposed to past time. This is called backshift. The present tense "is" becomes the past tense "was," and the present perfect "has been detected" becomes the past perfect "had been detected."