A key border crossing between Argentina and Chile has been temporarily closed after health officials detected a mosquito capable of transmitting dengue fever. The unusual measure, taken by Chilean authorities, halted traffic for 24 hours at the Los Libertadores border complex following the discovery of an Aedes aegypti mosquito, a known vector for the virus. This highlights the ongoing global efforts to prevent the spread of mosquito-borne illnesses.
The closure, impacting the Sistema Integrado Cristo Redentor (SICR) crossing, began at noon on Thursday, February 19, 2026, and lasted until noon on Friday, February 20, 2026. Authorities used the time to conduct a thorough disinfection of the area, which is frequented by customs agents and a high volume of vehicles and travelers. A similar, though shorter, disruption occurred last year, when the crossing was briefly closed for a few hours.
The origin of the mosquito remains unknown, but officials from the Chilean Ministry of Health located the insect inside a building as part of routine monitoring efforts. Chile is particularly vigilant in preventing the spread of dengue, as there are currently no locally acquired cases on the mainland. “The mosquito was inside the complex. It’s difficult for a truck to have brought it, because the insect disappears inside the cabin,” a source at the border crossing explained.
Chilean officials are taking a cautious approach to prevent any potential outbreaks, mirroring similar concerns regarding avian influenza, which has led to restrictions on poultry imports. “Chile is very attentive and careful to avoid any type of spread of the disease. The same happens with avian influenza, which is why they don’t allow chicken to pass, for example,” said a customs official.
The preventative health operation was ordered by Chilean authorities to allow for “chemical application” following the discovery of the “highly suspicious” Aedes aegypti specimen. The initial detection occurred on Wednesday, February 18, 2026, when a customs agent alerted health officials to the mosquito’s presence. This triggered a preventative control protocol and scheduled chemical treatment for Thursday.
Health authorities examined the sample and considered it “highly suspicious” of being a vector for dengue, Zika, or chikungunya. While awaiting confirmation from the Public Health Institute (ISP), entomological surveillance was conducted throughout the facility, including among personnel working at the border crossing.
“This is part of the coordinated function with the Provincial Presidential Delegation of Los Andes and with the teams that operate at the Los Libertadores Border Complex,” explained Carlos Zamora Rojas, representing the Chilean Regional Ministerial Secretariat of Health (Seremi). “Our strategy has allowed us not only to train teams from other institutions to recognize the mosquito, but also to keep the region free of autochthonous cases of dengue.” He added, “These actions allow us to establish a barrier and reduce the likelihood that the mosquito, which lives among us today, will continue to reproduce in strategic areas such as the border.” Officials confirmed that no individuals were exhibiting symptoms associated with the arboviruses transmitted by the mosquito.
Traffic was halted beginning at 10:00 a.m. On both the Argentine and Chilean sides of the border, in Uspallata and Guardia Vieja, respectively. Customs operations continued until noon before the complete closure of the crossing for all vehicles, prompting some travelers to adjust their plans. The border reopened at noon on Friday, February 20, 2026.
This is not the first time such an event has occurred. Last year, around the same time, Chilean authorities closed the international crossing for a few hours after detecting the dengue-transmitting mosquito, resulting in lengthy delays for travelers.
