Körsten Christin, Vasić Ana, Al-Hosary Amira A, Tews Birke A, Răileanu Cristian, Silaghi Cornelia, Schäfer Mandy
Institute of Infectology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, 17493 Greifswald, Germany.
Scientific Institute of Veterinary Medicine of Serbia, 11000 Belgrade, Serbia.
Trop Med Infect Dis. 2023 Aug 11;8(8):410. doi: 10.3390/tropicalmed8080410.
The increasing threat of arboviruses such as West Nile virus (WNV) and Usutu virus (USUV) requires the fast and efficient surveillance of these viruses. The examination of mosquitoes takes up an important part; however, these investigations are usually very time-consuming. An alternative sample type for arbovirus surveillance might be mosquito excreta. In order to determine the excretion dynamics under laboratory conditions, laboratory colonies of and biotype were infected with WNV, USUV or tick-borne encephalitis virus (TBEV). After infection, the excreta were sampled and investigated for viral RNA. Excretion of viral RNA together with infectious blood meal could be detected up to five days after infection. Further excretion seemed to correlate with a disseminated infection in mosquitoes, at least after USUV infection. In addition, it could be determined that the amount of viral RNA in the excretions correlated positively with the viral load in the mosquito bodies. Overall, this study shows that the usage of mosquito excreta as a sample type for surveillance enables the detection of endemic viruses (WNV, USUV) as well as non-mosquito-borne viruses (TBEV). In addition, examination of viral shedding during vector competence studies can provide insights into the course of infection without sacrificing animals.
西尼罗河病毒（WNV）和乌苏图病毒（USUV）等虫媒病毒构成的威胁日益增加，因此需要对这些病毒进行快速有效的监测。对蚊子的检测是其中的重要环节；然而，这些调查通常非常耗时。蚊虫排泄物可能是虫媒病毒监测的另一种样本类型。为了确定实验室条件下的排泄动态，将库蚊和致倦库蚊生物型的实验室种群感染WNV、USUV或蜱传脑炎病毒（TBEV）。感染后，采集排泄物样本并检测病毒RNA。感染后长达五天都能检测到病毒RNA与感染性血餐一起排出。至少在感染USUV后，进一步的排泄似乎与蚊子的播散性感染相关。此外，可以确定排泄物中病毒RNA的量与蚊子体内的病毒载量呈正相关。总体而言，这项研究表明，将蚊虫排泄物用作监测样本类型能够检测到地方性病毒（WNV、USUV）以及非蚊媒病毒（TBEV）。此外，在媒介能力研究期间检测病毒传播情况可以在不牺牲动物的情况下深入了解感染过程。
