Rozo-Lopez Paula, Londono-Renteria Berlin, Drolet Barbara S
Department of Entomology, Kansas State University, Vector Biology Laboratory, Manhattan, KS 66506, USA.
Arthropod-Borne Animal Diseases Research Unit, Agricultural Research Service, United States Department of Agriculture, Manhattan, KS 66502, USA.
Pathogens. 2021 Jun 29;10(7):816. doi: 10.3390/pathogens10070816.
biting midges are biological vectors of vesicular stomatitis virus (VSV) in the U.S. Yet, little is known regarding the amount of ingested virus required to infect midges, nor how their feeding behavior or age affects viral replication and vector competence. We determined the minimum infectious dose of VSV-New Jersey for midges and examined the effects of multiple blood-feeding cycles and age at the time of virus acquisition on infection dynamics. A minimum dose of 3.2 logs of virus/mL of blood resulted in midgut infections, and 5.2 logs/mL resulted in a disseminated infection to salivary glands. For blood-feeding behavior studies, ingestion of one or two non-infectious blood meals (BM) after a VSV infectious blood meal (VSV-BM) resulted in higher whole-body virus titers than midges receiving only the single infectious VSV-BM. Interestingly, this infection enhancement was not seen when a non-infectious BM preceded the infectious VSV-BM. Lastly, increased midge age at the time of infection correlated to increased whole-body virus titers. This research highlights the epidemiological implications of infectious doses, vector feeding behaviors, and vector age on VSV infection dynamics to estimate the risk of transmission by midges more precisely.
在美国，蠓是水疱性口炎病毒（VSV）的生物传播媒介。然而，对于感染蠓所需的病毒摄入量，以及它们的摄食行为或年龄如何影响病毒复制和传播能力，人们了解甚少。我们确定了VSV-新泽西毒株对蠓的最小感染剂量，并研究了多次吸血周期以及获取病毒时的年龄对感染动态的影响。每毫升血液中病毒含量至少达到3.2对数会导致中肠感染，而每毫升5.2对数会导致病毒扩散至唾液腺。在吸血行为研究中，在摄取VSV感染性血餐（VSV-BM）后再摄取一到两次非感染性血餐（BM）的蠓，其全身病毒滴度高于仅摄取单次感染性VSV-BM的蠓。有趣的是，当非感染性BM先于感染性VSV-BM时，未观察到这种感染增强现象。最后，感染时蠓的年龄增加与全身病毒滴度升高相关。这项研究突出了感染剂量、媒介摄食行为和媒介年龄对VSV感染动态的流行病学影响，以便更精确地估计蠓传播病毒的风险。
