African swine fever (ASF), a highly contagious disease of swine, has posed a significant global threat to the swine industry. As an archipelago, the Philippines has a geographic advantage when it comes to the risk of ASF transmission. However, since its introduction to the Philippines in 2019, it has proliferated not only in backyard and commercial farms but also in wild pig populations. While certain parts of the country were more affected than others, the epidemiologic features of ASF necessitate that all affected areas must be closely monitored and that confirmed cases be treated with the utmost care. With the very limited data on ASF epidemiology and surveillance in the Philippines, future efforts to combat ASF must place even greater emphasis on improved prevention and control strategies. It is worth mentioning that the government’s efforts toward comprehensive ASF surveillance and epidemiological investigation into the possible ASFV sources or transmission pathways are the most important measures in the prevention and control of ASF outbreaks. This review article provides a comprehensive overview of the current swine industry and ASF situation in the Philippines, which includes its epidemiology, surveillance, prevention, and control strategies.

Background and Aim: The indiscriminate use of antimicrobials in livestock farming has contributed to the emergence of antimicrobial-resistant pathogens, posing a significant public health challenge. This study aimed to assess the prevalence and antimicrobial resistance (AMR) profiles of Salmonella spp. isolated from swine and poultry in small- and medium-scale farms in Cambodia. Materials and Methods: A total of 638 fecal samples (273 rectal swabs from swine and 365 cloacal swabs from poultry) were collected from five provinces in Cambodia from June to September 2021. Salmonella spp. isolation followed ISO 6579:2002 guidelines, and antimicrobial susceptibility testing was conducted using the disk diffusion method, adhering to Clinical and Laboratory Standards Institute 2020 standards. Resistance was assessed against nine antimicrobial agents across five major classes. Results: Overall, Salmonella was detected in 6.58% (42/638) of samples, with 6.96% (19/273) from swine and 6.30% (23/365) from poultry. Swine-derived isolates exhibited the highest prevalence in the growing stage (13.93%), whereas poultry isolates were most common in avian broilers (14.55%). High resistance was observed against β-lactams (penicillin, amoxicillin, and ampicillin), tetracyclines, and sulfonamides, with resistance rates ranging from 73.81% to 100%. Fluoroquinolone resistance (ciprofloxacin and norfloxacin) was moderate (29.77%), while aminoglycoside resistance (gentamicin) was low (2.38%). Multidrug resistance (MDR) patterns were identified in 91.30% (21/23) of poultry isolates and 52.63% (10/19) of swine isolates, with resistance spanning three to five antimicrobial classes. Conclusion: The presence of Salmonella in Cambodian swine and poultry farms and its high level of MDR underscore the urgent need for improved antimicrobial stewardship. The study highlights the risk of MDR Salmonella transmission through livestock production chains, emphasizing the necessity for stringent regulatory interventions, biosecurity measures, and surveillance programs to mitigate AMR spread in animal agriculture and public health sectors. Keywords: antimicrobial resistance, Cambodia, multidrug resistance, poultry, Salmonella, swine.

Riemerella anatipestifer is one of the most devastating pathogens affecting the global duck farms. Infection is involved in secretion of proinflammatory cytokines, including interleukin- (IL-) 17A. During the immune response to infection, IL-22 and IL-17A are often produced concurrently and at high levels in inflamed tissues. Little is known about duck IL-22 (duIL-22) during R. anatipestifer infection. We describe the characterization of duIL-22 and its mRNA expression analysis in splenic lymphocytes and macrophages treated with heat-killed R. anatipestifer and in the spleens and livers of R. anatipestifer-infected ducks. Full-length cDNA of duIL-22 encoded 197 amino acids. The deduced amino acid sequence of duIL-22 shared a 30.440.5 similarity with piscine counterparts, 57.460.1 with mammalian homologs, and 93.4 similarity to the chicken. Duck IL-22 mRNA expression level was relatively high in the skin of normal ducks. It was increased in mitogen-stimulated splenic lymphocytes and in killed R. anatipestifer-activated splenic lymphocytes and macrophages. Compared with healthy ducks, IL-22 transcript expression was significantly upregulated in the livers and spleens on days 1 and 4 postinfection, but not on day 7. IL-17A was significantly increased in the spleens only on day 4 postinfection and in the livers at all time points. When splenic lymphocytes were stimulated with heat-killed R. anatipestifer, CD4⁺ cells predominantly produced IL-22 while IL-17A was expressed both by CD4⁺ and CD4^- cells. These results suggested that IL-22 and IL-17A are likely expressed in different cell types during R. anatipestifer infection.

African swine fever (ASF) is a contagious hemorrhagic disease affecting both domestic and wild 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 imperative to identify risk factors that may contribute to its transmission. The Philippines' current ASF surveillance relies on pig blood samples. With this very limited epidemiological data, it is imperative to include raw meat and processed pork products due to high ASF transmission risks. In this study, a total of 384 raw pork and 384 processed pork products from selected wet markets were collected and detected the ASF virus (ASFv) VP72 gene using real-time polymerase chain reaction (rt-PCR), and the overall positivity rates were 10.16% and 10.68%, respectively. Moreover, an interview with wet market vendors was conducted, and the Least Absolute Shrinkage and Selection Operator (LASSO) regression was employed to identify possible factors associated with sample positivity. Results showed that ASFv-positive samples were linked to zoning status, rainy seasons, Longganisa preparation, selling different meat types, longer pork batches, and cleaning or disinfection in market stalls. Overall, ASFv contamination in pork and processed pork products 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. Therefore, there’s a need to address this risk by strict surveillance and proper handling procedures throughout the food supply chain.

Flores RA, et al. J Vet Sci. 2022 Oct;23:e91. https://doi.org/10.4142/jvs.22170

Bernardo JM, et al. J Vet Sci. 2024 Dec;26:e2. https://doi.org/10.4142/jvs.24149