author(s)
Sunanda Majumdar, Mohammad Amir, Ritika Gupta and Shagufta Yasmeen

abstract
Periplaneta americana, the American cockroach is a major nuisance and also act as mechanical vector in transmitting bacteria that cause diarrheal diseases, nosocomial infections and allergic symptoms. Deltamethrin, in the concentrations 0.005% and 0.01% were provided in feed of adult cockroaches to observe histopathological changes in midgut after 24 hours. Midgut is lined with enteric epithelium which rest upon a basement membrane and is covered by inner circular and outer longitudinal muscles. Midgut contains a thin peritrophic membrane as innermost layer. Histopathological studies on midgut resulted in degradation of basement membrane and degeneration in epithelial lining in both concentration (0.01% and 0.005%). Higher dose caused more disruption in longitudinal and circular muscles as compared to low dose. Peritrophic membrane was detached from epithelial lining and is degenerated to great extent in high dose. In lower concentration slight constriction is observed in lumen while at higher concentration shrinkage is more pronounced.