Rift Valley fever virus detection in susceptible hosts with special emphasis in insects

Abstract

Rift Valley fever phlebovirus (RVFV, Phenuiviridae) is an emerging arbovirus that can cause potentially fatal disease in many host species including ruminants and humans. Thus, tools to detect this pathogen within tissue samples from routine diagnostic investigations or for research purposes are of major interest. This study compares the immunohistological usefulness of several mono- and polyclonal antibodies against RVFV epitopes in tissue samples derived from natural hosts of epidemiologic importance (sheep), potentially virus transmitting insect species (Culex quinquefasciatus, Aedes aegypti) as well as scientific infection models (mouse, Drosophila melanogaster, C6/36 cell pellet). While the nucleoprotein was the epitope most prominently detected in mammal and mosquito tissue samples, fruit fly tissues showed expression of glycoproteins only. Antibodies against non-structural proteins exhibited single cell reactions in salivary glands of mosquitoes and the C6/36 cell pellet. However, as single antibodies exhibited a cross reactivity of varying degree in non-infected specimens, a careful interpretation of positive reactions and consideration of adequate controls remains of critical importance. The results suggest that primary antibodies directed against viral nucleoproteins and glycoproteins can facilitate RVFV detection in mammals and insects, respectively, and therefore will allow RVFV detection for diagnostic and research purposes.

Immunohistochemical Characterization of the Nervous System of Culex pipiens (Diptera, Culicidae)

“…Morphological characterization of head ganglia was performed in Culex pipiens and Drosophila melanogaster after determination of the sectional plane using routine hematoxylin and eosin-stained slides. Immunohistochemistry was performed as previously described [ 26 ]. Sections were deparaffinized (Roticlear, #A538.3, Carl Roth GmbH and Co. KG, Karlsruhe, Germany), rehydrated and incubated with 0.5% hydrogen peroxide (H 2 O 2 ; #9681.1, Carl Roth GmbH and Co. KG, Karlsruhe, Germany) in 85% ethanol to inactivate the endogenous peroxidase.…”

“…Although arboviruses replicate in both host and vector, no apparent detrimental effects are observed in the latter [ 23 , 24 ]. However, in addition to infection of the nervous system [ 23 , 25 , 26 , 27 , 28 ], there is evidence that arboviruses alter vector behavior [ 29 ]. Arbovirus-infected mosquitoes have repeatedly shown behavioral changes, including altered locomotor activity, host-seeking or feeding behavior [ 23 , 24 , 30 , 31 , 32 , 33 ].…”

NO Synthesis in Immune-Challenged Locust Hemocytes and Potential Signaling to the CNS

“…Blocking solution (PBS-T with 5% normal goat serum, Invitrogen, Thermo Fisher, Waltham, MA, USA) was applied for 30 min. Mouse-anti-RVFV antibody Gn164b [ 73 ], which stains RVFV glycoprotein in various tissues of different mammalian and insect species [ 74 ], was used 1:50 in blocking solution on abdomens overnight. Subsequently, abdomens were washed twice with PBS-T for 5 min.…”

NSG-Mice Reveal the Importance of a Functional Innate and Adaptive Immune Response to Overcome RVFV Infection

“…RVFV strain MP-12 propagation follows previously published protocols [47]. Briefly, it was propagated on Vero-76 cells in Dulbecco's Modified Eagle's Medium (DMEM, #DMEM-HXA, Capricorn Scientific GmbH, Ebsdorfergrund, Germany)/2% fetal bovine serum (FBS; #FBS-HI-12A FBS, Capricorn Scientific GmbH, Ebsdorfergrund, Germany) under environmental conditions of 37 • C and a CO 2 content of 5%.…”

“…RVFV-infected and non-infected cell pellets were used as positive and negative controls, respectively. Details of the staining protocols have been published previously [47,68,69].…”