Biology subjects

Gebrewold, M.

Publications and source records attributed to Gebrewold, M..

3 recordsLinked to original sources

bioRxiv2025

Detection of Japanese Encephalitis (JE) Virus in Piggery effluent from an Australian Farm Prior to Outbreaks of JE

Japanese encephalitis virus (JEV), a mosquito-borne orthoflavivirus, raises concerns about its seasonal re-emergence. Pigs are a major amplifying host and JEV infection can manifest as significant reproductive disease and losses, necessitating robust surveillance. This study evaluated effluent surveillance for early JEV detection in piggery effluent from a Victorian farm between December 2024 and March 2025. Effluent samples were tested using JEV-specific real-time reverse transcription (RT)-PCR, with positive detections found on four separate sampling days, despite an absence of clinical signs in livestock through the testing period. Subsequent veterinary investigations for JEV in litters born on 17/05/2025 (suspect cases only) aligned with a positive effluent sample collected during the estimated JEV infection exposure periods of the sows. With the single clinically confirmed JEV case (which farrowed on 1/06/2025) collection of the same positive effluent sample fell just outside, but near, the estimated exposure period for the affected sow. These findings highlight ability of effluent monitoring to detect JEV infection 2 to 4 months before clinical manifestations present, offering potential for a non-invasive, herd-level early warning system. Intermittent detections may suggest limitations in grab sampling and low viral loads in effluent samples. Integrating effluent surveillance with veterinary clinical testing of litters suspected of being exposed to JEV or during high-risk periods could enhance JEV management in Australias enzootic regions, supporting One Health strategies.

molecular biology↗

bioRxiv2025

In-situ calibration of passive samplers for monitoring host-associated fecal markers in an urban river

Passive sampling in aquatic environments has shown promise as a time- and cost-efficient method with improved sensitivity for detecting microbial pollution in dynamic and variable conditions. However, quantitative descriptions of its field performance have been scarce, impeding its broader application in environmental settings. The performance of two membrane-based passive samplers (Torpedo and MSTFlow) in quantifying human (Carjivirus, Pepper Mild Mottle Virus [PMMoV], Tomato Brown Rugose Fruit Virus [ToBRFV]) and avian (Helicobacter spp. GFD marker) fecal pollution markers in an urban riverine environment over a 72-h deployment was evaluated using a first-order kinetic model to characterize their microbial adsorption characteristics. Results were compared with those from parallel composite and time-weighted auto-sampling. Accumulation in passive samplers exhibited an initial lag phase (0 to 8 h for viruses) and reached equilibrium within 16 h of initial deployment, except for GFD. Sampling rates were highest for PMMoV (6.29 and 5.11 mL/h) for MSTFlow and Torpedo samplers respectively, followed by Carjivirus (4.63 and 3.63 mL/h), ToBRFV (2.17 and 1.22 mL/h) and GFD (0.68 mL/h in Torpedo sampler). At equilibrium, both sampler configurations accumulated more than 22-170 times the amount of target gene copies in each mL of grab water samples depending on sampler and virus. These findings highlight passive sampling as a promising, sensitive, cost-effective, and low-maintenance alternative for continuous microbial water quality monitoring in aquatic environments. Overall, this study advances the understanding of passive sampling kinetics and supports broader adoption of passive samplers for tracking fecal pollution in environmental waters.

microbiology↗

bioRxiv2025

Surveillance of Japanese Encephalitis Virus in Piggery Effluent and Environmental Samples: A Complementary Tool for Outbreak Detection

Japanese encephalitis virus (JEV) is an emerging public health and biosecurity concern in Australia, with recent human cases and detections in mosquitoes and pigs across multiple states highlight the risk to susceptible human and animal populations. While traditional surveillance methods such as mosquito trapping, sentinel chicken programs and direct testing of pig specimens remain essential, monitoring effluent offers a valuable complementary approach for detecting infections within animal populations. This study presents the first evidence of JEV in Australian piggery effluents/environmental waters, demonstrating the feasibility of effluent and environmental water surveillance for JEV monitoring. Effluent/environmental samples from multiple piggery sites were analyzed using real-time reverse transcription polymerase chain reaction (RT-PCR), revealing the presence of JEV genetic fragments in solid and liquid fractions of effluents at three farms, with corresponding veterinary cases in some herds. Viral RNA was detected more frequently in solid fraction of effluent samples, aligning with previous findings on the partitioning behaviour of mosquito-borne viruses. The detection of JEV in the borrow pit (i.e., a man-made excavation that holds water) water sample highlights potential transmission pathways via mosquito vectors. These findings demonstrate the value of effluent monitoring as an additional tool for JEV surveillance in piggery settings, supporting potential early warning systems and mitigation strategies. Integrating effluent-based monitoring with traditional surveillance approaches could improve livestock industry related disease detection, risk assessments, and response efforts for human and animal health in endemic and emerging regions. Wastewater/effluent surveillance may have important applications for the management of a wide range of emerging animal diseases. IMPORTANCEThis study presents the first evidence of Japanese encephalitis virus (JEV) detection in Australian piggery effluents, establishing effluent surveillance as a valuable complementary tool for monitoring viral pathogens in animal populations. Our findings support the integration of effluent monitoring with traditional surveillance systems to improve early warning capabilities, enhance biosecurity, and mitigate risks to both animal and human health.

molecular biology↗