Mexico’s Ministry of Health has confirmed a troubling rise in cases of human myiasis—an infection caused by parasitic larvae—with 31 reported incidents in the country between July 6 and July 12, 2025. Of these, a staggering 29 occurred in the southern state of Chiapas, while the remaining two cases were identified in Campeche, according to the General Directorate of Epidemiology’s latest bulletin.
Myiasis, caused by fly larvae (often Dermatobia hominis or Cochliomyia hominivorax), occurs when these parasites infest human tissue. Known locally as GBG (Gusanera Bovina de Gusano), the condition can lead to severe inflammation and tissue destruction if not properly treated.
Health authorities noted that the majority of infections were concentrated in the head region, though cases were also recorded in the neck, trunk, oral and nasal cavities, arms, legs, genitals, and uterus—indicating widespread tissue vulnerability. The affected patients ranged in age from 17 to 86 years.
In Chiapas, the infections were distributed across 14 municipalities:
- Tapachula: 7 cases
- Chilón: 3 cases
- Huixtla: 3 cases
- Escuintla: 2 cases
- Villa Comaltitlán: 2 cases
- Tonalá: 2 cases
- Ocosingo: 2 cases
- Mapastepec: 2 cases
- Mazatán, Yajalón, Huehuetán, Suchiate, Pichucalco, and Chamula: 1 case each
In Campeche, one case was reported in Ciudad del Carmen and another in Candelaria.
The bulletin notes a slight gender disparity in Chiapas: 20 of the infected are men, and 9 are women. In Campeche, the two cases include one male and one female patient.
According to the Ministry of Health, three individuals remain hospitalized due to the severity of their conditions. The rest have either been discharged after showing improvement, are recovering under outpatient care, or remain in delicate but stable condition.
Myiasis is more common in tropical and subtropical climates, particularly in regions with poor hygiene, limited access to healthcare, and high fly populations. The parasitic larvae can enter the human body through open wounds, mucous membranes, or even intact skin, where they feed on living or necrotic tissue.
In Mexico, myiasis is a neglected tropical disease that has historically affected rural populations, especially those working in agriculture or living in unsanitary conditions. The larvae may go undetected until the host begins to experience pain, swelling, discharge, or visible movement under the skin.
The World Health Organization (WHO) classifies myiasis as a serious vector-borne condition that requires increased public health awareness, particularly in regions where environmental and socioeconomic conditions allow the fly populations to thrive.
In response to the outbreak, the Ministry of Health is urging communities, especially in affected areas like Chiapas and Campeche, to take preventive measures:
- Maintain personal and household hygiene
- Promptly treat open wounds and cover them with sterile dressings
- Avoid areas with high fly activity, especially during the rainy season
- Seek immediate medical attention if symptoms like skin ulcers, unusual pain, or unexplained swelling arise
Local health departments in Chiapas and Campeche are reportedly conducting vector control campaigns, including fly reduction efforts, and are working with rural clinics to ensure rapid diagnosis and treatment of suspected cases.
With global climate change and urban encroachment into rural areas, public health experts warn that myiasis could become increasingly common in previously unaffected zones. Surveillance, education, and early medical intervention remain critical to preventing future outbreaks.
As of now, health officials continue to monitor the situation closely, and further updates are expected in subsequent epidemiological reports.
