Two human screwworm cases confirmed in Guanajuato; both are elderly adults

The Secretariat of Health of Guanajuato (SSG) has confirmed two cases of myiasis caused by the screwworm fly (Cochliomyia hominivorax) in elderly residents of Celaya and Tierra Blanca municipalities. Both patients, aged 75, received timely medical attention, specific treatment, and specialized follow-up.

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The screwworm is an infestation caused by fly larvae that deposit their eggs mainly in open wounds.

These individuals have successfully completed their epidemiological surveillance period. Their ongoing medical follow-up is related to pre-existing chronic health conditions unrelated to the myiasis infestation. As of May 18, 2026, the state had detected 221 cases of screwworm infestation in animals across 18 municipalities.

Guanajuato ranks 13th nationally in human myiasis cases, with its two confirmed human infections accounting for only 0.8% of the 254 national cases. The SSG stated that the state has one of the lowest incidences of human screwworm cases in the country.

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This is a preventable and treatable condition when identified early and treated promptly by health personnel.

Health authorities are maintaining active epidemiological surveillance in all medical units and coordinating with federal, sanitary, and agricultural bodies to strengthen early detection, prevention, and timely care. The SSG emphasized that screwworm infestation is preventable and treatable if identified and treated early. The condition does not transmit from person to person, and there is no generalized risk to the population of Guanajuato.

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This condition is not transmitted from person to person, and, at the moment, there is no generalized risk situation for the Guanajuato population.