In rodent models, tissues collected at the time of death do not typically contain abundant WNV-infected
cells due to prior clearance by the immune system, so it is not possible to understand viral tropism and pathogenesis without sampling tissues throughout the course of disease development (Siddharthan et al., 2009 and Tesh et al., 2005). Herein lies the value Compound C of rodent models in that they have been used in temporal studies to determine that the virus can infect many areas of the brain and spinal cord and subsequently affect neurological functions. Some WNV patients complain of confusion or altered mental status (Carson et al., 2006) (Table 1). In a retrospective study with 54 persons
about a year and a half after acute illness, the study cohorts scored below the 15 percentile on some cognitive tests as compared to normative controls. (Sejvar et al., 2008). Further human studies should be done to confirm these results, but rodent models could also help to identify neurological mechanisms of cognitive deficits. The greatest density of lesions in WNV-infected hamsters is observed in the area of the prefrontal cortex (PFC) (Siddharthan et al., 2009), which plays a critical role in cognition and executive functions in humans and rodents. Extensive studies in the rat model have revealed that sub-regions of the PFC control distinct components of cognitive executive function (Chudasama and Robbins, 2006 and Dalley ISRIB order et PIK-5 al., 2004). Additional WNV-induced lesions are also observed in the limbic system particularly with the hippocampus (Hunsperger and Roehrig, 2006 and Siddharthan et al., 2009) and thalamus (Ali et al., 2005 and Davis et al., 2006). Lesions in these anatomical regions might affect cognitive function via disturbance of connections between the PFC and the limbic system. Behavioral assays in rodents coupled
with virological and histological assays could elucidate the effect that WNV might have on cognitive and executive functions. Some WNV patients describe symptoms that may reflect a loss of proprioception (Moon et al., 2005) (Table 1), which is a declining sense of the relative position of neighboring parts of the body. The cerebellum is involved in coordinating this communication to motor functions. Rodent models could possibly be useful for these investigations inasmuch as WNV can infect the cerebellum in rodents. Some disease signs and symptoms of WNV encephalomyelitis are consistent with dysfunction of the autonomic nervous system, i.e., respiratory, cardiac, renal and gastrointestinal functions (Table 1). The most widely recognized WNV-induced disease sign controlled by autonomic function is respiratory distress (Betensley et al., 2004 and Sejvar et al.