Prevalence of gastrointestinal parasitism in pigs of Tripura, India.

Pigs breeds are an important livestock species mostly reared by economically lower incomesection of people in India. Within North-Eastern (NE) states, pig husbandry is very much popular hence maintain the livelihood of the rural native population. Gastrointentinal (GI) parasitic infectionisone of the major constraint in profitable pig production in this area. In the present study, the GI parasitism was investigated in 388 pigs in the three districts of Tripura, NE State of India. The examination of faecal samples revealed 61.65% overall prevalence of parasitic infestation, precisely6 GI parasitic species; including 4 nematodes and 2 protozoa, while 46.91% were the mixed infections.Metastrongylus spp. (17.53%), Strongyloids spp. (19.33%),Trichuris spp. (15.98%), Coccidia spp. (12.37%), and Balantidium coli (10.82%), were detected, however, Ascaris spp. was the most prevalentrecording 32.47%. The epidemiological factors including: age, sex, season, breed, area and farming system wise when considered as markers of study showed the highest prevalence of GI parasites in grower(6-12 months) stage, female, monsoon season, non-descript breeds, Khowai district and free range farming system, recorded 71.52%, 67.27%, 65.78%, 65.71%, 64.57%, and 69.44%, respectively. Overall, our study provides a baseline data for further investigation and formulation of strategies for control of GI parasitism in pigs in Tripura.

Characterization of interferon gamma gene in relation to immunological responses in Haemonchus contortus resistant and susceptible Garole sheep.

Garole sheep exhibits within-breed difference in resistance to natural gastrointestinal nematode infection predominated by Haemonchus contortus. In the present study, interferon gamma gene (IFN-γ) was characterized in relation to parasitological, haematological, and immune response against H. contortus in resistant and susceptible Garole sheep. Resistant and susceptible Garole sheep were selected from the field based on consistent low faecal egg counts (FEC) for one year and single nucleotide polymorphisms (SNPs) in the IFN-γ gene. The partial amplification of IFN-γ gene (1282 bp) revealed 4 SNPs exclusively in resistant sheep and 3 SNPs were shared between resistant and susceptible Garole sheep. The selected resistant and susceptible Garole sheep were challenged with H. contortus infection. The parasitological, haematological, immunological responses, and expression of IFN-γ gene were compared between the resistant and susceptible Garole sheep. The FEC of resistant sheep was significantly (P < 0.05) lower than the susceptible sheep infected with H. contortus. There was spontaneous elimination of H. contortus from 28 to 33 days post infection (DPI) in resistant sheep. Haemoglobin and packed cell volume were significantly (P < 0.05) higher in resistant sheep than the susceptible sheep. The serum concentration of immunoglobulin (Ig)G1 and IgA and cytokine IFN-γ activity and also the expression of IFN-γ gene were significantly (P < 0.05) higher in the infected resistant sheep from 14 to 28 DPI compared to the susceptible sheep. In resistant sheep, IgA and IgG1 and cytokine IFN-γ positively correlated with expression of IFN-γ gene, and the SNPs recorded in the resistant sheep only might play an important role in conferring resistance against H. contortus. Further studies are required to elucidate the role of IFN-γ gene in H. contortus resistance in Garole sheep.

Parasitological and immunological response to Haemonchus contortus infection: Comparison between resistant Garole and susceptible Sahabadi sheep.

Parasitological and immunological responses to the experimentally induced Haemonchus contortus infection were compared between Garole and Sahabadi breeds of sheep. The experiment was conducted in a 2 (breed) × 2 (infection status) factorial arrangement with a completely randomised design. Two breeds of sheep were divided into infected (n = 10) and control (n = 6) groups, and the infected groups were orally infected with H. contortus (500 stage 3 larvae per kilogram of body weight). Faecal egg counts (FEC) were determined from 18 days post infection (DPI) at 3-day intervals until 42 DPI. Average daily body weight gain, packed cell volume (PCV), concentrations of serum immunoglobulin (Ig) G1, IgG2, IgE and peripheral eosinophil count were measured at 14-day intervals from 0 to 42 DPI. Lymphocyte proliferation in response to somatic antigen of H. contortus was determined by in vitro lymphoproliferation assay, and concentrations of interferon gama (IFN-γ) and interleukin 4 (IL-4) in lymphocyte culture supernatant were measured at 14-day intervals until 42 DPI. Variables were analysed using the repeated measures mixed model procedure over DPI. Faecal egg count was significantly (p < 0.01) lower in Garole sheep than Sahabadi sheep and no faecal eggs were detected in the infected Garole sheep on 30 DPI. Infected Garole sheep had significantly (p < 0.05) higher body weight gain and PCV% than the infected Sahabadi sheep. In the infected Garole sheep, serum Ig except IgE increased significantly (p < 0.05) compared to infected Sahabadi sheep. On 28 DPI, peripheral eosinophil number, in vitro lymphoproliferation as well as concentrations of IFN-γ and IL-4 in culture supernatant were significantly (p < 0.05) higher in the infected Garole sheep than in the infected Sahabadi sheep. Parasitological observations indicated that Garole sheep were resistant to H. contortus and they exhibited greater cellular as well as humoral immune responses compared to Sahabadi sheep.

Oral route of transmission: Trypanosoma evansi in a mice model experiment.

Twelve Swiss albino mice of either sex and equal body weight were randomly divided in 2 groups (I and II), consisting of 9 and 3 mice respectively and were used to conduct the study. A dose of 2.5 × 104 number of Trypanosoma evansi was instantly fed to each mouse of group I. Each mouse of group II was inoculated intraperitoneally with same dose of parasites through infected mice blood and kept separate. The tail blood of each mouse was examined daily up to 30 days post infection by examination of wet blood film and Giemsa-stained blood smears for presence of any trypanosomes. Out of 9 mice of group I those were infected orally, 3 (33.33%) mice became positive for presence of T. evansi both by examination of wet blood film and Giemsa-stained blood smears after 4, 6 and 7 days post infection. After 2 days post infection all intraperitoneally infected mice were found positive for T. evansi. Thus incubation period in orally infected mice was longer than the intraperitoneally infected mice. All the positive mice of both the groups died with high parasitaemia after 3-4 days of first appearance of parasitaemia. From the present study, it can be concluded that besides mechanical or parenteral means of transmission, T. evansi could also be transmitted through oral route. Thus zoo carnivores might be infected with T. evansi and develop disease by eating infected blood or flesh of the infected animals, as a prey and predator relationship.