The government of Colombia has confirmed 32 cases of infant birth defects tied to the Zika virus, while a total number of 50 cases are investigated for ties to the disease. While birth defects tied to Zika have been rampant in Brazil, these are the first cases outside the epicenter of the Zika outbreak currently underway in South America.

The birth defect in question is microcephaly, a condition where an infant is born with a skull too small for his or her head. The skull crushes the brain, causing a variety of neurological abnormalities. Brazilian health authorities have asserted that they believe “most” of the more than 5,000 cases of microcephaly surfacing since the Zika outbreak began have been caused by the virus, but outside of Brazil, Zika has not been found to cause as many fetal abnormalities. USA Today notes that Panama, Martinique, and the United States have both documented one case each of microcephaly believed to be related to Zika. The African nation of Cape Verde has documented another two. Colombia now has 32.

The Brazilian virologist who first identified the presence of Zika in the country, Gubio Soares, suggested in February that one reason it has taken years to find a link between microcephaly and Zika contamination is that previous outbreaks have occurred in countries where abortion is unregulated, and women who did not know they were carrying Zika likely aborted their children when told they would be born with severe neurological problems. In Brazil, abortion is legal only in cases where the mother’s health is endangered, and each abortion must be approved by a judge.

The Spanish-language newswire service EFE notes that Colombian medical officials have documented 50 cases of microcephaly this year, twenty more than the record annual number of cases. If diagnoses continue to occur at this pace, Colombia will have documented 500 cases of Zika-related birth defects by the end of the year.

The Zika virus does not trigger symptoms in eighty percent of its carriers. In the twenty percent who do exhibit signs of contamination, the symptoms are described as milder forms of those associated with Dengue fever: flu-like fatigue, conjunctivitis, and fever. The World Health Organization (WHO) issued an announcement this week definitively concluding Zika can cause microcephaly. “Based on observation, cohort, and control studies, there exists a strong scientific consensus that Zika is a cause of Guillain-Barre Syndrome (GBS), microcephaly, and other neurological disorders,” the WHO said in a statement.

GBS is a neurological disorder that causes extreme muscle pain, paralysis, and death. It is treatable through physical therapy or administering immunoglobulin or human albumin intravenously. It has surfaced most commonly in Venezuela, as years of socialist mismanagement of its health care system has left the nation struggling to overcome a severe drug shortage. At least 11 people have died in Venezuela of GBS believed to have ties to Zika contamination, with a total of 3,000 GBS cases suspected of having its origins in Zika infection.

Definitively linking microcephaly to Zika is a difficult task for doctors because of the many potential causes of such a birth defect. The U.S. Centers of Disease Control (CDC) list rubella, toxoplasmosis, cytomegalovirus, severe malnutrition, alcohol, drugs, and toxic chemicals as potential causes of microcephaly. Confirmed cases are those where doctors have confirmed the presence of Zika in the infant’s bloodstream, not just the mother’s. Confirming the presence of Zika can be difficult in smaller clinics in the more remote locations in Latin America that have been hit hardest by the Zika outbreak.

The CDC is hosting a summit Friday for medical experts to discuss the latest developments on the fight to contain Zika as spring and summer weather approach in the United States. The most common way to contract Zika is through the bite of the Aedes aegypti mosquito, present in all countries of the Western Hemisphere save for Chile and Canada. Doctors have also documented several cases of sexually-transmitted Zika.

“The mosquitoes that carry Zika virus are already active in U.S. territories, hundreds of travelers with Zika have already returned to the continental U.S., and we could well see clusters of Zika virus in the continental U.S. in the coming months. Urgent action is needed, especially to minimize the risk of exposure during pregnancy,” CDC Director Tom Frieden said of the conference.