Emergence of oriental theileriosis in cattle and its transmission through Rhipicephalus (Boophilus) microplus in Assam, India

Aim: The aim of the present study was to investigate the presence of Theileria in blood samples of crossbred and indigenous adult cows raised under unorganized small scale farming system in a Babesia and Anaplasma endemic geographical area from Assam, India and to see its transmission through Rhipicephalus (Boophilus) microplus ticks. Materials and Methods: For the present study, 57 clinical cases of cattle suspected to be of hemoparasitic infections were taken into consideration. The parasites were identified based on morphology in giemsa stained blood smear followed by polymerase chain reaction (PCR). Sera samples were tested for T. annulata antibodies in plate and Dot-ELISA. PCR was also conducted in eggs of Rhipicephalus (Boophilus) microplus tick collected from a Theileria orientalis positive animal. Results: PCR amplified 1124, 776, and 160 bp DNA fragments of B. bigemina (64.91%),T. orientalis(21.05%) and A. marginale (14.03%), respectively. This assay further conducted in 12 T. orientalis positive blood samples with primers of Buffeli, Chitose, and Ikeda variants of T. orientalis showed 3 samples positive to Ikeda type and none for Buffeli and Chitose. Babesia bovis and Theileria annulata specific primers also did not amplify any fragment during the PCR assay of the blood samples. Further, all sera samples tested negative to T. annulata antibodies in Plate and Dot-ELISA. PCR conducted in eggs of R (B).microplus tick collected from a T. orientalis positive animal revealed presence of the parasite DNA. Gradual improvement in physical condition leading to complete recovery in 10 out of 12 T. orientalis infected clinical cases treated with buparvaquone(at 2.5mg/kg.b.wt I/M) was the feedback obtained from field veterinarians and the cattle owners. Conclusion: The present investigation represents the first report of occurrence of T. orientalis in cattle of Assam with involvement of pathogenic Ikeda strain in clinical outbreaks and its possible natural transmission by R (B). microplus through the transovarian mode

Listeriosis in a peri-urban area: Cultural and molecular characterization of Listeria monocytogenes isolated from encephalitic goats

Background and Aim: Listeriosis in food animals bears a significant threat to human health. Detailed investigations into the cause facilitate proper management of the disease. This study reports the cultural, pathological, and molecular characterization of Listeria monocytogenes isolated from encephalitic goats from peri-urban Guwahati, Assam. Materials and Methods: Out of nine suspected samples, five positive isolates of L. monocytogenes were subjected to bacteriological, biochemical, and molecular tests. The genus and species-specific L. monocytogenes 16S rRNA and prs genes were amplified by polymerase chain reaction (PCR) to yield 1200 and 370 bp sized products, respectively. The encephalitic form of the disease was characterized by circling movement, high fever, and terminal recumbence. Results: All the five isolates were confirmed to be L. monocytogenes based on PCR amplification of genus and species-specific 16S rRNA and prs gene products. The isolates were sensitive to ciprofloxacin, oxytetracycline (OTC), and norfloxacin, but resistant to doxycycline and erythromycin. A high dose of OTC was used in a goat at the early stage of clinical symptom and the animal recovered clinically. Conclusion: Listeriosis in goats could pose a significant public health threat as the meat (occasionally milk) or meat products from goats are widely consumed by the people of Assam. Understanding the molecular epidemiological aspects of L. monocytogenes infections of food animal species should, therefore, be the priority in this part of the country

Thermostability and Immunogenicity of Genotype II Avian Orthoavulavirus (AOaV-1) Isolates from Duck (<i>Anas platyrhynchos</i>) and Parrot (<i>Eclectusroratus</i>)

Newcastle disease (ND) is a highly contagious viral disease of poultry causing significant economic losses worldwide. Vaccination is considered the most reliable approach to curb the economic menace that is ND, but the thermolabile nature of Newcastle disease virus (NDV) vaccination poses a significant threat to its protective efficacy. This study aimed to profile the thermostability of NDV isolates from duck (As/Km/19/44) and parrot (As/WB/19/91) and evaluate their immunogenic potential in chicks. Fusion protein cleavage site (FPCS) and phylogenetic analysis demonstrated the lentogenic nature of both the isolates/strains and classified them as class II genotype II NDV. The characterized NDV isolates were adapted in specific-pathogen-free (SPF) chicks by serially passaging. Biological pathogenicity assessment of chicken-adapted As/Km/19/44 (PSD44C) and As/WB/19/91 (PSP91C) revealed both the isolates to be avirulent with a mean death time (MDT) of more than 90 h and an intracerebral pathogenicity index (ICPI) ranging from 0.2 to 0.4. Both of the NDV isolates displayed varied thermostability profiles. PSD44C was the most thermostable strain as compared to PSP91C and the commercially available LaSota vaccine strain. The immunogenicity of PSD44C and LaSota was significantly higher than PSP91C. Based on these results, it is concluded that NDV isolate PSD44C is more thermostable and immunogenic when administered intraocularly without any adverse effects. Therefore, PSD44C is suitable for further research and vaccine development