Comparative comprehensive analysis on natural infections of Hymenolepis diminuta and Hymenolepis nana in commensal rodents

Abstract

Summary This first comprehensive report from Punjab province of India relates to patho-physiological alterations alongwith morpho-molecular characterisation and risk assessment of natural infections of Hymenolepis diminuta and Hymenolepis nana in 291commensal rodents including house rat, Rattus rattus (n=201) and lesser bandicoot rat, Bandicota bangalensis (n=90). Small intestine of 53.61 and 64.95 % rats was found infected with H. diminuta and H. nana, respectively with a concurrent infection rate of 50.86 %. There was no association between male and female rats and H. diminuta and H. nana infections (ᵡ2 = 0.016 and 0.08, respectively, d.f.= 1, P>0.05), while the host age had significant effect on prevalence of H. diminuta and H. nana (ᵡ2 = 28.12 and 7.18, respectively, d.f.= 1, P≤0.05) infection. Examination of faecal samples and intestinal contents revealed globular shaped eggs of H. diminuta without polar filaments (76.50 ± 3.01μm x 67.62 ± 2.42 μm), while smaller sized oval eggs of H. nana were with 4 – 8 polar filaments (47.87 ± 1.95 μm x 36.12 ± 3.05 μm). Cestode infection caused enteritis, sloughing of intestinal mucosa, necrosis of villi and inflammatory reaction with infiltration of mononuclear cells in the mucosa and submucosa. Morphometric identification of the adult cestodes recovered from the intestinal lumen was confirmed by molecular characterisation based on nuclear ITS-2 loci which showed a single band of 269 bp and 242 bp for H. diminuta and H. nana, respectively. Pairwise alignment of the ITS-2 regions showed 99.46 % similarity with sequences of H. diminuta from USA and 100 % similarity with sequences of H. nana from Slovakia, Kosice.