Two people who traveled to Nicaragua have returned to Costa Rica infected with the Zika virus, health authorities said Wednesday, bringing to 12 the number of people with Zika infections in Costa Rica.

Of the total, there have been eight indigenous cases, all of which where contracted in the canton of Nicoya, specifically in Nosara and Samara, in the province of Guanacaste. The remaining cases have been “imported” cases of infection, where the patient contracted the virus during a trip abroad.

The imported cases include a Costa Rican man who contracted the virus during a trip to Colombia, a Honduran man who arrived in Costa Rica after contracting the virus in his native country, and the two imported cases from Nicaragua announced by health authorities on Wednesday.

Health authorities say they have managed to halt the spread of the virus in Nicoya, where all of the indigenous cases of infection have occurred, by eliminating more than 130,000 active and potential breeding sites of the Aedes aegypti mosquito, which spreads Zika as well as the dengue and Chikungunya viruses.

Costa Rica’s Ministry of Health had declared a health emergency in the canton on February 22^nd when two women – one of them pregnant – were determined to be the first indigenous cases of Zika infection in the country.

On February 2^nd, the US Centers for Disease Control (CDC) included Costa Rica in a list of countries where Americans should avoid travel as a result of the virus, after a tourist from the United States fell ill with the virus after visiting the country. The WHO followed suit three days later.

The Zika virus has been linked to microcephaly, a condition linked to the virus and which causes babies to be born with abnormally small heads and brains.