Swine Viral Evolution and Vaccine Development Research Unit, Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Henry Dunant Road, Pathumwan, Bangkok, 10330, Thailand.
MSD Animal Health Innovation Pte Ltd, Singapore, 718847, Singapore.
Sci Rep. 2023 Mar 21;13(1):4600. doi: 10.1038/s41598-023-31199-2.
Shared needles are a possible iatrogenic and hematogenous inanimate vector of African Swine Fever virus (ASFV) in farm conditions. To evaluate that possible transmission, sixty, 4-week-old pigs were procured from an ASF free herd free. Upon arrival, pigs were randomly divided into two sets. Set 1 served as seeder pigs, and were randomly allocated to 4 groups. The other pigs were divided into 8 groups, and served as sentinels. Seeder pigs were oronasally challenged with ASFV at high (10 copy numbers/mL), moderate (10 copy numbers/mL) or low (10 copy numbers/mL) challenge titer, except a subgroup that remained unchallenged (negative control). At 7 days post challenge (peak viremia), all four seeder groups were intradermally and intramuscularly (IM) injected with a vaccine adjuvant (Diluvac Forte, MSD Animal Health, The Netherlands) using a needle-free device (IDAL 3G, MSD Animal Health, The Netherlands) and conventional needles, respectively. The same needle or needle-free device was then used to inject the same volume of adjuvant into set 2 (n = 48) pigs. All pigs were observed for clinical disease daily and assayed for the presence of ASFV DNA by quantitative PCR. All seeder groups developed viremia (except the control pigs). ASFV viremia was detected in all sentinel groups injected via the intramuscular route. Transmission rate from the IM route via conventional needles was positively correlated with virus titer in blood circulation of seeders. Sentinels intramuscularly exposed to needles from high titer challenged seeders displayed more severe and acute clinical disease compared to that of exposed to low titer challenged seeders. No viremia nor clinical signs were observed in the sentinel groups injected via the intradermal route. This study confirmed the hematogenous transmission of ASFV between pigs through needle-sharing.
共用针头是非洲猪瘟病毒（ASFV）在农场条件下可能的医源性和血源性无生命载体。为了评估这种可能的传播，从无 ASFV 的猪群中获得了 60 头 4 周龄的猪。到达后，猪被随机分为两组。一组作为播种猪，并随机分为 4 组。其余猪分为 8 组，作为哨兵。播种猪经口挑战高（10 拷贝数/mL）、中（10 拷贝数/mL）或低（10 拷贝数/mL）滴度的 ASFV，除了一个保持未挑战的亚组（阴性对照）。在攻毒后 7 天（病毒血症高峰），所有 4 个播种组均通过无针设备（IDAL 3G，MSD Animal Health，荷兰）和常规针头皮内和肌肉内（IM）注射疫苗佐剂（Diluvac Forte，MSD Animal Health，荷兰）。然后，同一根针或无针设备被用于将相同体积的佐剂注入第二组（n=48）猪中。所有猪每天观察临床疾病，并通过定量 PCR 检测 ASFV DNA 的存在。所有播种组均出现病毒血症（除对照猪外）。通过 IM 途径注射的所有哨兵组均检测到 ASFV。通过常规针头从 IM 途径传播的传播率与播种者血液中的病毒滴度呈正相关。与暴露于低滴度挑战播种者的哨兵相比，从高滴度挑战播种者接受肌肉内注射的哨兵显示出更严重和急性的临床疾病。通过皮内途径注射的哨兵组均未检测到病毒血症或临床症状。本研究证实了 ASFV 通过共用针头在猪之间的血源性传播。
