Clogmia albipunctata fails to induce true intestinal myiasis: Evidence from in vitro and in vivo digestive models.

Abstract

Clogmia albipunctata (C. albipunctata) is a synanthropic moth fly frequently found in humid human environments. Larvae of this species have been reported in suspected cases of intestinal myiasis, but whether they can establish true gastrointestinal infestation remains uncertain. This study evaluated the survival, development, and colonization potential of C. albipunctata using in vitro digestive models and murine oral gavage models. Wild-caught moth flies were reared in artificial climate chambers to establish laboratory colonies. Species identification was subsequently performed through morphological characterization and molecular analysis. The in vitro digestion model exposed C. albipunctata eggs and larvae to simulated gastrointestinal fluids, and their survival was monitored. For in vivo assessment, BALB/c mice were orally gavaged with viable eggs. Feces were examined for seven consecutive days, and gastrointestinal tissues were evaluated by time-point necropsy and histological examination. Laboratory colonization of C. albipunctata was successfully achieved, and the species identity was confirmed. The in vitro digestion model demonstrated that standard simulated gastric fluid acts as a lethal barrier. Specifically, egg hatchability decreased from 76.80% ± 3.57% in controls to 0% after digestion, and larval mortality increased from 19.17% ± 3.01% to 99.17% ± 0.83% after simulated gastric exposure. While simulated postprandial weakly acidic conditions (pH 2.0-5.0) partially attenuated this lethality, sequential intestinal fluid exposure induced further mortality. In vivo, the oral gavage of viable eggs and live first-instar larvae in mice resulted in no fecal shedding, tissue injury, or pathological colonization in the gastrointestinal tract. These findings indicate that healthy murine gastrointestinal conditions and simulated human digestive fluids are highly unfavorable for the survival and colonization of C. albipunctata eggs and larvae. The results support the interpretation that many suspected clinical cases may represent sample contamination or pseudomyiasis rather than true intestinal myiasis.