Intracerebral Inoculation of Mouse-Passaged Saffold Virus Type 3 Affects Cerebellar Development in Neonatal Mice

Neuropathology in Neonatal Mice After Experimental Coxsackievirus B2 Infection Using a Prototype Strain, Ohio-1

Coxsackievirus B (CVB) causes severe morbidity and mortality in neonates and is sometimes associated with severe brain damage resulting from acute severe viral encephalomyelitis. However, the neuropathology of CVB infection remains unclear. A prototype strain of coxsackievirus B2 (Ohio-1) induces brain lesions in neonatal mice, resulting in dome-shaped heads, ventriculomegaly, and loss of the cerebral cortex. Here, we characterized the glial pathology in this mouse model. Magnetic resonance imaging revealed an absence of the cerebral cortex within 2 weeks after inoculation. Histopathology showed that virus replication triggered activation of microglia and astrocytes, and induced apoptosis in the cortex, with severe necrosis and lateral ventricular dilation. In contrast, the brainstem and cerebellum remained morphologically intact. Immunohistochemistry revealed high expression of the coxsackievirus and adenovirus receptor (a primary receptor for CVB) in mature neurons of the cortex, hippocampus, thalamus, and midbrain, demonstrating CVB2 infection of mature neurons in these areas. However, apoptosis and neuroinflammation from activated microglia and astrocytes differed in thalamic and cortical areas. Viral antigens were retained in the brains of animals in the convalescence phase with seroconversion. This animal model will contribute to a better understanding of the neuropathology of CVB infection.

Evidence of Saffold virus circulation in Italy provided through environmental surveillance

Saffold virus (SAFV) is an emerging human cardiovirus associated with respiratory and gastrointestinal infection, and, more recently, to symptoms related to the endocrine, cardiovascular, and neurological systems. Information about SAFV circulation in Italy is scarce. In order to provide insights into the epidemiology of SAFV in Italy, 141 raw sewage samples collected throughout Italy were tested using broad-range nested RT-PCR primers targeting the 5'-NC region. Seven samples (5·0%) were confirmed as SAFV in samples collected in North, Centre and Southern Italy. Typing was attempted through amplification of the VP1 coding region, using both published and newly designed primers, and one sample was characterized as SAFV-2. SIGNIFICANCE AND IMPACT OF THE STUDY: Prevalence, genetic diversity and geographic distribution of SAFV in Italy is currently unknown. This study represents the first detection of SAFV in sewage samples in Italy, suggesting that it is circulating in the population despite lack of clinical reporting. Whether the virus is associated with asymptomatic cases or with undetected gastroenteritis or respiratory illness is unknown. Further studies are needed to investigate on the occurrence and persistence of SAFV in water environments and its waterborne transmission potential.