In early 2026, Mexico confirmed 25 new cases of myiasis caused by screwworm fly larvae, bringing the national total of affected people to 135, according to the National Epidemiological Surveillance System (SINAVE) of the Ministry of Health. The cases correspond to the last three epidemiological weeks and show a territorial expansion of this parasitic infection, particularly in the south of the country. From January 4 to 10, 12 cases were reported: seven concentrated in Chiapas, four in Yucatán, and one in Quintana Roo. In the following week, from January 11 to 17, 10 more infections were confirmed: four in Chiapas, two in Yucatán, three in Oaxaca, and one in Quintana Roo. Between January 18 and February 3, three other cases were documented; one corresponded to a 69-year-old man in Chiapas, and the other two to men aged 74 and 53 in Guerrero, a state that had not previously reported screwworm myiasis in humans. By federal entity, Chiapas leads the list with 99 of the 135 accumulated cases. It is followed by Yucatán with 14, Quintana Roo and Oaxaca with six each, Campeche with four, and Tabasco, Veracruz, and Guerrero with two cases each. The most recent epidemiological report indicates that, as of the cut-off date, 10 people were receiving outpatient treatment and seven remained hospitalized, without specifying the clinical condition of the rest of the patients. The Ministry of Health began registering screwworm myiasis in humans in April 2025, when the first case in the country was reported in a 77-year-old woman from the municipality of Acacoyagua, in Chiapas. From that moment, a special follow-up was established due to the re-emergence of this disease. In Chiapas, municipalities where patients have been identified include Mapastepec, Tapachula, Escuintla, Villa Comaltitlán, Huixtla, Pichucalco, Tonalá, Ocosingo, Chilón, Mazatán, Yajalón, Huehuetán, Suchiate, Chamula, Cacahoatán, and Pijijiapan. In Campeche, cases were located in Ciudad del Carmen and Candelaria, while in Guerrero they were reported in the municipality of Copala and Azoyú. Information from the Ministry of Health states that screwworm myiasis is an infection caused by fly larvae that develop in living tissues, usually from open wounds. Although Mexico was declared free of this pest in 1991, health authorities maintain active epidemiological surveillance following the confirmation of human cases. The Ministry of Health reiterated its call to immediately seek medical attention for injuries with signs of infection and to report any suspected case, in order to avoid complications and contain the spread of this disease. Screwworm in animals Data from the National Service of Health, Safety and Food Quality (Senasica) indicate that as of Epidemiological Week 5, with a cut-off date of February 2, 2026, there are 726 active cases of screwworm in animals, mainly in cattle with 429; 166 in dogs and one in birds. Oaxaca is the most affected entity with 174 cases, Chiapas with 141, Veracruz with 117; Colima and Jalisco have only registered one case each. The state of Guerrero accumulates 79, Campeche 23, Yucatán 48, and the State of Mexico 57. From November 20, 2024, to February 2, 2026, Mexico has accumulated 14,978 cases of screwworm.
