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

Abstract Background and objectives Cockroach gut houses mostly anaerobic microbial communities. Most of these eukaryotes live as endocommensal rather as pathogenic entity. The morphological diversity of the eukaryotic microorganisms present in the intestinal tract of American cockroach, Periplanata americana were investigated. Methods Cockroach host 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 PAS method was performed to observe mucopolysaccharide utilization and localization. Prevalence of all microscopic specimens was also noted. Results The study revealed the assemblage of complex eukaryotic fauna showing unique morphological peculiarities. Two oxyurid helminth genuses namely Hammerschmidtiella and Thelastoma were isolated with 44% and 68% prevalence respectively. Among the protozoans the highest prevalence was shown by Nyctotherus ovalis (91.2%). Feulgen reaction revealed that in most of the specimen micronucleus was embedded over the macronucleus of N. ovalis. PAS positive granules were mostly located in the anterior one third region of the cell. A new species of Nyctotheruswas also described (Nyctotherus membralis) showing characteristic membrane fold. Iodamoeba bütschlii (Prowazek, 1912) was isolated and reported for the first time from Kolkata, West Bengal, India. Another human pathogen reported to cause lung infection, Lophomonas striata was also detected with a prevalence of 9%. A moderate number of Endamoeba blattae (41%) and Gregarine blattarum (18%) isolated from hind gut and mid gut respectively. Conclusions Iodamoeba bütschlii was detected for the first time from Kolkata, West Bengal, India. The isolation of Lophomonas striata, the potential pathogen of human lungs from cockroach gut constitutes a major health risk. Discovery of new species of the ciliate Nyctotherus from cockroach hind intestine also stimulates interest on its contribution towards the host physiology.