LONDON (Reuters) - Britain's world and Olympic heptathlon champion Jessica Ennis-Hill, 30, is deeply concerned about the threat of the Zika virus in Brazil ahead of this summer's Olympics in Rio de Janeiro.

An outbreak of the mosquito-borne Zika virus, linked to numerous cases of the microcephaly birth defect in Brazil, has spread in Latin America and the Caribbean, causing panic and leading some athletes to consider whether to attend the Games.

"It is worrying, really concerning," Ennis-Hill told the Daily Telegraph.

"I have to make sure I understand what's happening and what the risks are. It's something I have to be on top of."

Ennis-Hill, who won the heptathlon world title in Beijing last August, 13 months after giving birth to her son Reggie, said she wanted more children and was constantly monitoring updates from the British Olympic Association (BOA).

She wanted to take her son to Rio for what will be her final Olympics but would delay making a decision until she had considered all the risks.

"It will be a late call," she added. "I want to be able to compete in a state of mind where I don't have to worry about whether he's OK or whether he's safe."

The Rio Olympics take place from Aug. 5-21.