Characterizing gut fauna of American cockroach: Presence of Lophomonas striata and Iodamoeba bütschlii.

Cockroach gut houses mostly anaerobic microbial communities. Most of these eukaryotes live as endocommensal rather as pathogens. The morphological diversity of the eukaryotic microorganisms present in the intestinal tract of American cockroach, Periplanata americana were investigated. Cockroaches were dissected in 0.67% saline and temporary iodine wet mount were prepared. Microrganisms were stained permanently with Delafield and Heidenhain haematoxylin. Feulgen methods were used to study nuclear organization and Periodic acid-Schiff method was performed to observe mucopolysaccharide localization. Prevalence of isolated specimens was also determined. The study revealed the assemblage of complex eukaryotic fauna showing unique morphological peculiarities. Two oxyurid helminth genera namely Hammerschmidtiella and Thelastoma were isolated with 47.1 and 67.6% prevalence respectively. Among the protozoans the highest prevalence was shown by Nyctotherus ovalis (91.2%). Feulgen reaction revealed that in most of the specimens micronucleus was embedded over the macronucleus of N. ovalis. Periodic acid-Schiff positive granules were mostly located in the anterior one third region of the cell. Here, a new species of Nyctotherus (Nyctotherus membranfoldis n.sp.) was found in the hind gut of Periplaneta americana showing characteristic membrane folds with a prevalence rate of 11.8%. We also report the occurrence of Iodamoeba bütschlii (prevalence 2.94%) from hind gut smear of cockroach not previously reported in Kolkata, West Bengal, India. Another human pathogen reported to cause lung infection, Lophomonas striata was also detected with a prevalence of 11.8%. A moderate number of Endamoeba blattae (41.2%) and Gregarine blattarum (14.7%) were isolated from the hind gut and mid gut of Periplaneta americana respectively. Iodamoeba bütschlii was detected in Kolkata not previously detected in the city. The isolation of Lophomonas striata, a potential pathogen of human lungs, from cockroach gut constitutes major health risk for humans. Discovery of new species of the ciliate Nyctotherus (Nyctotherus membranfoldis) from cockroach hind intestine also may have a role in the host physiology as well disease causing potentiality in humans.