Condition factor and organosomatic indices of parasitized Rattus rattus as indicators of host health.

This study describes the influence of parasitism (Trypanosoma lewisi and Cysticercus fasciolaris) on the condition factor, hepato and splenosomatic indices of the common house rat, Rattus rattus Linnaeus, 1758 from Rohilkhand, Uttar Pradesh, India. Examination of R. rattus (n = 389) revealed T. lewisi (prevalence 12.40 %; intensity14 parasites/1000 RBC) from the blood and C. fasciolaris (larval Taenia taeniaeformis) (prevalence 46.70 %; intensity 2-4 par/host) from the liver. Condition factor (K) and organosomatic indices [hepatosomatic index, spleenosomatic index (SSI)] were evaluated in two groups (Group I non pregnant, Group II pregnant) of female rats which were further subdivided into four subgroups each (a Uninfected, b T. lewisi infected, c C. fasciolaris infected, d T. lewisi and C. fasciolaris infected) belonging to three weight groups (A 50-100 g; B 100-150 g; C 150-200 g). The results indicated that reduction in K-factor was more apparent in young rats, Group Ic (weight category A) showing the maximum depletion (21.62 %), hepatomegaly and splenomegaly were frequent outcomes of parasitic infection and maximum change (50 %) was recorded in dual-infected pregnant rats (Group IId) expressed as SSI of the infected rat. The abnormal condition factor and organosomatic indices indicate perturbations in the biological systems at the organismal level. Thus, the information generated through this piece of work is a warning of an incipient or impending problem.