Therapeutics and prophylactic efficacy of novel lytic Escherichia phage vB_EcoS_PJ16 against multidrug-resistant avian pathogenic E. coli using in vivo study.

Avian pathogenic Escherichia coli (APEC) is the causative agent of avian colibacillosis, which causes significant economic losses to the poultry industry. The growing resistance of bacteria to antibiotics is a major global public health concern. However, there is limited data on the efficacy of phage therapy in effectively controlling and treating APEC infections. In this study, a novel lytic Escherichia phage, vB_EcoS_PJ16, was isolated from poultry farm wastewater and characterized in both in vitro and in vivo conditions. Transmission electron microscopy analysis revealed the presence of an icosahedral head and a long non-contractile tail, classifying the phage under the Caudoviricetes class. Host range determination showed that Escherichia phage vB_EcoS_PJ16 exhibited lytic activity against multiple strains of pathogenic E. coli, while no significant signs of lysis for Klebsiella pneumoniae, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus. Biophysical characterization revealed that the isolated phage was sturdy, as it remained viable for up to 300 days at temperatures of 30 °C, 37 °C, and 42 °C and for up to 24 h at pH 5 to 11, with only minor changes in titer. Kinetic analysis at multiplicity of infection (MOI) 0.1 showed a latency period of about 20 min and a burst size of 26.5 phage particles per infected cell for phage vB_EcoS_PJ16. Whole genome sequencing unveiled that the phage vB_EcoS_PJ16 genome consists of a double-stranded linear DNA molecule with 57,756 bp and a GC content of 43.58%. The Escherichia phage vB_EcoS_PJ16 genome consisted of 98 predicted putative ORFs, with no transfer RNA identified in the genome. Among these 98 genes, 34 genes were predicted to have known functions. A significant reduction in APEC viability was observed at MOI 100 during in vitro bacterial challenge tests conducted at different MOIs (0.01, 1, and 100). In vivo oral evaluation of the isolated phage to limit E. coli infections in day-old chicks indicated a decrease in mortality within both the therapeutic (20%) and prophylactic (30%) groups, when compared to the control group. The findings of this study contribute to our current knowledge of Escherichia phages and suggest a potentially effective role of phages in the therapeutic and prophylactic control of antibiotic-resistant APEC strains.

Molecular investigations on outbreaks of ovine theileriosis among sheep and goats in Haryana, India.

During February 2020 to October 2020, four outbreaks of theileriosis in small ruminants were recorded with overall morbidity, mortality and case fatality rates of 27.95%, 17.46% and 62.5%, respectively. The disease was characterized by high fever (up to 106°F), superficial lymphadenopathy, anaemia, anorexia, lethargy, respiratory distress and death. The presence of pleomorphic intra-erythrocytic piroplasms of Theileria species in Giemsa's stained blood smears was a common finding in all the episodes. Significant haematological alterations including high total leucocyte count and low haemoglobin and packed cell volume were characteristic. Necropsy findings of the icteric liver, enlarged spleen, pulmonary oedema and abomasal ulcerations were observed in three flocks. Smear-positive blood samples from all the episodes were screened by PCR using 18S rRNA gene-specific primer sets for T. lestoquardi, T. luwenshuni, T. uilenbergi and T. ovis. T. lestoquardi which was detected in all four flocks, while there was co-infection of T. ovis in two flocks. Phylogenetic analysis revealed that T. ovis and T. lestoquardi identified in this study had 100% and ~ 99.86% homology, respectively, with the published sequences used for comparison. This is the first confirmed report of outbreaks of malignant ovine theileriosis in the Haryana state of India which caused high morbidity, mortality and case fatality among sheep and goats. Further studies on theilerioses in small ruminants are required to understand epidemiology better.

GIS-augmented survey of poultry farms with respiratory problems in Haryana.

Among various infectious diseases of poultry, diseases of the respiratory tract are responsible for considerable economic losses. The present study was conducted to evaluate some of the risk factors, which included locations of farm, ventilation facilities, number of farms in 1 km2 area, agro-climatic zone, and age of flock in relation to respiratory problem in Haryana, India. One hundred poultry flocks with respiratory problems were identified and selected for conducting the survey. The "ODK Collect" app installed on a smartphone was used to capture coordinates of the farms. The collected data was accessed through http://odkproject-iirs.appspot.com/ . The location of farms was mapped with the help of QGIS. All the three parameters, viz., morbidity, mortality (p < 0.001), and case fatality rate (CFR) (p = 0.045), were significantly higher in birds of age 0-2 weeks. Natural ventilation was the most common facility observed in the present study (51/100). Maximum morbidity and mortality were observed in small flocks (< 10,000), whereas maximum CFR was observed in medium-sized flocks (> 10,000-30,000), and there was a significant difference in morbidity, mortality, and CFR. Further, there was a significant difference between agro-climatic zones with respect to morbidity and mortality (p < 0.001). It can be concluded that age, flock size, and agro-climatic conditions have an impact on intensity of diseases especially respiratory diseases. Therefore, special precautions should be taken for young flock. Flock size should be adequate, and such management practices should be adopted that are suitable for particular climatic conditions.