(Reuters) - Condom makers including Ansell Ltd are offering to help Zika-affected countries after the first case of the virus being sexually transmitted added to growing concerns over the spread of the disease.

The virus, which is spreading quickly across the Americas, is usually transmitted by mosquitoes. But, the first known case contracted in the United States was a person infected after having sex with someone who had returned from Venezuela.

World Health Organization (WHO) spokesman Gregory Hartl stressed that “almost a 100 percent of the cases” are transmitted by the bite of a mosquito.

However, the possibility of Zika being sexually transmitted adds a new dimension to the threat the disease poses.

“Ansell will be approaching regional associations in Brazil and other countries to offer its assistance and expertise in alleviating this major public health issue,” Jeyan Heper, president and general manager of the Australian company’s sexual wellness global business unit told Reuters in an email.

Ansell, which makes Skyn and Lifestyles condoms as well as industrial and surgical gloves, said it provided nearly 1 million surgical gloves to fight the Ebola outbreak in West Africa in 2014.

Female Health Co, which makes condoms for women, said it has been in contact with various health agencies, including the U.S. Centers for Disease Control and Prevention and the WHO, and has seen a growing number of enquiries.

“We are working with the local health ministers at these countries to help provide the product that they will either be distributing or recommending to the public,” Michele Greco, chief financial officer of the U.S.-based company told Reuters.

Trojan condom maker Church & Dwight Co Inc said it has been in touch with various public health agencies for regular status updates and that it would continue to monitor the situation closely to determine appropriate next steps.

The WHO said at least 26 countries in the Americas have a Zika outbreak, and countries such as Ireland, Australia and Canada have reported cases of travelers testing positive for the virus after visiting an infected area.

Companies ranging from vaccine developers to mosquito repellant makers have come under the spotlight after the outbreak, as they work with government agencies to combat the rising threat.

Durex condoms maker Reckitt Benckiser Group Plc did not respond to emails and calls seeking comment.