This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.
The Global African Swine Fever Research Alliance (GARA) builds global research partnerships to combat African Swine Fever (ASF). Its goals include identifying research gaps, studying ASF’s impact, developing and evaluating control tools, and promoting knowledge sharing. GARA coordinates efforts toward ASF control and eradication. Their latest meeting was held in Rome, Italy, in April 2025. Two selected abstracts from the proceedings are included below.
The full proceedings can be found at: https://insights.crdfglobal.org/hubfs/USDA/GARA%202025%20Abstract%20Booklet%20Final.pdf?hsLang=en
Risk Assessment of ASFV Transmission in Pork Products and Molecular Detection in Visayan Warty Pigs in the Philippines
Cherry P. Fernandez-Colorado, Aaron Paul R. Serdeña, John Michael G. Bernardo, Saubel Ezrael A. Salamat, Gladys Maria V. Pangga, Trisha Nicole Agulto, Monica Atienza, Wanetta dela Calzada, Emilia A. Lastica-Ternura
University of the Philippines Los Baños, Philippines
African swine fever (ASF) is a contagious hemorrhagic disease affecting pigs with high mortality rate and severe socio-economic losses. Due to the virus’ potential ability to remain infectious in suitable conditions and environments, it is important to identify risk factors that may contribute to its transmission. Currently, ASF surveillance in the Philippines relies on pig blood samples, providing limited data on transmission risks from contaminated pork and potential wildlife reservoirs. In addition, ASF transmission risk evaluation currently includes positive cases, population density, and pork production volume, but the potential roles of contaminated pork commodities and wild pigs remain unexplored. In this study, a total of 384 raw and 384 processed pork products from selected wet markets were collected and detected the ASFV VP72 gene using real-time polymerase chain reaction (rt-PCR), and the overall positivity rates were 10.16% and 10.68%, respectively. Based on the regression analysis employed, positive samples were associated with factors like zoning status, season, ‘Longganisa’ preparation, selling different meat types, pork batch duration, and market practices like cleaning and disinfection. Furthermore, a risk assessment identified six provinces with high ASF transmission risk due to positive pork samples and high ASF incidence, while four provinces had consistently low risk. The difference in the meat contamination level between low and high-risk provinces emphasized the importance of including this factor in ASF spread assessment. Additionally, molecular detection of ASFV was conducted in fecal samples from Visayan warty pigs (Sus cebifrons) in one conservation center in the Philippines. Among fifteen (15) wild pig fecal samples tested, five (5) were positive for ASFV, confirming the virus’s presence in wild pig populations2. This finding suggests that wild pigs may serve as an additional reservoir for ASFV, posing a risk for further spread to domestic swine and pork commodities. Overall, ASFV contamination in raw and processed pork products and its detection in wild pigs can pose a threat to the swine industry, and market practices may further lead to ASFV persistence in these commodities which may contribute to ASF spread. These findings highlight the need for comprehensive ASF surveillance and monitoring of pork products and wild pig populations, stricter handling practices throughout the food supply chain, and targeted resource allocation to high-risk areas to control ASF spread in the Philippines.
Comparison of oral, nasal and anal swabs for detection of African swine fever virus by qPCR in vaccine efficacy studies
Nadia Oreshkova¹, Sandra Vreman¹, C. Coral Dominguez-Medina¹, Jan Boonstra¹, Richard Draaijer¹, Jacob Post¹, Linda Peeters¹, Tosca Ploegaert¹, Alexander Schäfer², Virginia Friedrichs², Sandra Blome²
¹ Wageningen Bioveterinary Research, Wageningen University and Research, Lelystad, The Netherlands
² Friedrich-Loeffler-Institut, Institute of Diagnostic Virology, Greifswald-Insel Riems, Germany
African Swine Fever Virus (ASFV) studies often assess virus shedding using oral (OS), nasal (NS), and anal (AS) swabs. To improve animal welfare, reducing the number of swabs may be considered if research objectives allow. We compared ASF viral DNA detection via qPCR in OS, NS, and AS samples during a multicenter vaccine efficacy study conducted at Friedrich Loeffler Institute (FLI), Germany, and at Wageningen Bioveterinary Research (WBVR), Netherlands, within an EU collaboration. Three live attenuated vaccine candidates (n=15, FLI; n=10, WBVR) were tested via oral administration. One of the candidates was tested intramuscularly (IM, n=8, WBVR) as an efficacy control, and unvaccinated controls (n=5 at both institutes) were included. All animals were challenged oronasally with the Armenia ’08 strain. Swabs were collected during the vaccination and challenge phases, and qPCR was used to detect viral DNA. At WBVR, ASFV DNA was detected in 7/152 OS (oral vaccines) and 10/32 OS (IM vaccine) samples during the vaccination phase. Only 1/32 NS and no AS samples tested positive. During the challenge phase, 34/43 OS samples were positive at 2 days post-infection (dpi), compared to 6 NS and 0 AS. NS and AS positivity increased at later time points, but overall, the numbers of positive OS was higher. At FLI, one OS and one NS (out of 180) samples were positive during the vaccination phase. After challenge, 23/50 OS, 18/45 NS, and 11/50 AS samples were positive at 4 dpi. Positive OS and NS numbers equalized later, while AS remained consistently lower. OS were the most sensitive samples for detecting virus shedding during the vaccination phase and early post-challenge and were superior or comparable to NS and AS at later stages. These results suggest OS sampling alone is sufficient for assessing ASFV shedding in vaccine studies, improving animal welfare by minimizing invasive procedures.