Molecular identification and genetic variability of equine and bovine ocular setariasis in india: molecular profiling by mitochondrial genes.

BACKGROUND: Ocular setariasis is an ectopic infection caused by a parasite under the genus Setaria. Adult worms belong to the Setariidae family and typically reside in the peritoneal cavity of ungulates. However, immature forms of these species may aberrantly migrate to the eyes of cattle, buffalo, goats, horses and several other hosts, leading to corneal opacity and blindness. Here, we have distinguished the Setaria digitata collected from both equine and buffalo hosts based on the morphology, molecular profiling of mitochondrial cytochrome c oxidase subunit 1 (Cox1), cytochrome c oxidase subunit 3 (Cox3) and, Nicotinamide Adenine Dinucleotide dehydrogenase subunit 1 (NAD1) genes. METHODS AND RESULTS: A single filarial worm was collected from the eye of one equine and one bovine host. These worms were then processed for morphological examination and DNA isolation. Cox1, Cox3 and NAD1 genes were amplified using specific primers and subjected to custom sequencing. The sequences were then used for multiple sequence alignment, assessment of entropy, similarity and haplotype diversity analysis. Key morphological features confirmed the worms collected were male and female Setaria digitata from equine and buffalo hosts, respectively. Cox1, Cox3 and NAD1 gene sequence analysis showed a close association of S.digitata Indian isolates with its counterparts from Sri Lanka and China isolates. CONCLUSION: The phylogram of bovine S. digitata sequences shows a close relationship to other equine S. digitata sequences, indicating the need for further in-depth studies on the prevalence of infection across various host species and intermediate hosts. Although the sequence results suggest that S. digitata is likely the causative agent of ocular setariasis in India, additional samples are needed to confirm this conclusion. Comprehensive analysis of the transcriptome and proteome of S. digitata from both bovine and equine hosts is necessary to explore variations in host-parasite interactions. These findings will aid in future parasite identification, investigations into vector prevalence in India, and the development of control measures against ocular setariasis.

Prevalence of haemoprotozoan diseases in cattle of Cauvery delta region of Tamil Nadu.

A study was carried out to determine the prevalence of haemoparasites in cattle in Cauvery delta region over a period of one year. A total of 228 giemsa stained blood smears were screened for the presence of haemoprotozoa, out of which 34 animals were found to be positive. An overall prevalence of haemoparasites in the sampled cattle were 14.9%, among this Anaplasma sp (8.3%), Babesia sp (3.95%), Theileria sp (2.19%) and Trypanosoma sp (0.44%) as single or mixed blood parasitic infections. In this study Anaplasmosis (14%) was highly prevalent during the winter season and Babesiosis (13.73%) was highly prevalent during summer months followed by Anaplasmosis (9.8%) and Theileriosis (7.8%), the lowest prevalence of Trypanosomiasis was observed during the rainy season. The seasonal variation in prevalence of haemoprotozoan disease might be due to influence of climatic factors on density of vector population in that geographical area. Haemogram revealed decreased level of haemoglobulin, packed cell volume and total erythrocyte count. The serum biochemistry revealed elevated level of liver enzyme Asparate transaminase enzyme. All haemoparasitaemic animals were treated with specific drugs and recovered successfully.

Influence of sustained deworming pressure on the anthelmintic resistance status in strongyles of sheep under field conditions.

Anthelmintic resistance (AR) status in Madras Red sheep from selected field flocks of a government funded scheme, covered by regular, sustained anthelmintic treatment for more than 10 years was determined. Parameters such as fecal egg count reduction test (FECRT), larval paralysis assay (LPA), and allele-specific-PCR (AS-PCR) were used to test the efficacy of fenbendazole, tetramisole, and ivermectin at recommended doses, in two seasons. Sheep belonging to non-beneficiary farmers were used as controls. Mean FECRT values of beneficiary group during winter and summer seasons were 77.77 and 76.04, 93.65 and 92.12, and 95.37 and 98.06 %, respectively, for fenbendazole, tetramisole, and ivermectin. In the non-beneficiary groups, the corresponding values were 74.82 and 81.09 %, 96.05 and 97.40 %, and 97.26 and 98.23 %, respectively. The results revealed resistance to fenbendazole, suspect resistance to tetramisole and susceptibility to ivermectin in beneficiary flock. In non-beneficiary flock, while resistance was noticed against fenbendazole, both tetramisole and ivermectin were effective. FECR values were found to be significantly different between beneficiary and non-beneficiary groups against tetramisole. The results of LPA confirmed this finding, as 50 % of the Haemonchus contortus larvae were paralyzed at the concentration of 0.0156 µg/ml in the beneficiary group, while those of non-beneficiary groups required lower concentrations of 0.0078 µg/ml. AS-PCR revealed the predominance of heterozygous susceptible population of H. contortus in the beneficiary group. In this study, resistance to fenbendazole was confirmed in both the beneficiary and non-beneficiary groups and this could be attributed to frequent use of benzimidazoles as seen from the deworming records. Emergence of tetramisole resistance was detected in the beneficiary group, where the drug was used continuously for 4 years. Ivermectin was found to be effective in all the flocks. It is recommended that the practice of routine deworming of three to four times a year should be avoided, as it can lead to emergence of anthelmintic resistance.