Replication and Tissue Tropism of the Alphavirus Sindbis in the Mosquito Aedes albopictus

Abstract

We have examined the replication and tissue distribution of the alphavirus Sindbis in the mosquito Aedes albopictus. Parenteral inoculation of virus resulted in an acute infection accompanied by rapid virus replication and a persistent infection, during which total virus production was reduced. Acute and persistent phase virus RNA synthesis, virus production, and organ-specific distribution of infection were determined over an 18-day incubation period. Organs were classified as refractory (ovarioles, Malpighian tubules), cleared (head ganglia), transient (salivary glands, anterior midgut, posterior midgut, and thoracic muscle), or persistent (fat bodies-hemolymph, hindgut, and tracheole-associated cells) according to the onset, peak, and duration of Sindbis virus antigens within that particular organ. Virus was identified in respiratory tissue by immunological and ultrastructural methods. This represents a novel tropism for an alphavirus. These findings demonstrate that the cells of mature insect organs respond differently to virus infection. Correlations among virus replication, virus RNA synthesis, and organ-specific clearing of a pantropic infection were observed. We suggest that the underlying temporal and spatial kinetics that characterize this virus-invertebrate interaction may reflect a mechanism for the modulation of the arbovirus titer seen in the mosquito host.

An Antiviral Role for Antimicrobial Peptides during the Arthropod Response to Alphavirus Replication

“…Vertebrates infected with alphaviruses develop an acute infection that is cleared by the host immune system, while arthropods maintain a persistent infection, which is crucial for efficient transmission (5,6). How arthropod hosts respond to alphaviruses and influence their amplification leading to a persistent infection is still not well understood.…”

Blood Feeding Position Increases Success of Recalcitrant Mosquitoes

“…aegypti (Orlando) and Ae. albopictus (Skuse) were hatched, reared, and maintained in the University of North Florida insectary maintained at 25.58C AE 0.58C, 70%-80% relative humidity, and 16:8 (light:dark) photoperiod as previously described (Bowers et al 1995). Female and male adults were housed together for 5 days in white bucket cages topped with mosquito netting, supplied ad lib with honeysoaked cellucotton, and water-saturated cotton.…”

Sub-clinical infection of farmed Atlantic salmon Salmo salar with salmonid alphavirus— a prospective longitudinal study

“…This is in contrast to infectious salmon anaemia virus (ISAV), where saithe have been shown to be resistant to infection and not to play a significant role in the epizootiology of the infection (Snow et al 2002, McClure et al 2004). Additional work is required to confirm this preliminary finding, particularly in light of the poor specific antibody response typically observed in gadoids to infectious agents (Samuelsen et al 2006) Although insect vectors have not been identified for SAV, they form an important part of the epidemiology of other alphavirus infections (Walton et al 1973, Bowers et al 1995. Recently, the elephant seal louse Lepidophthirus macrorhini has been proposed as the vector for the newly identified alphavirus named southern elephant seal virus (SESV) (La Linn et al 2001).…”