Arenaviridae Notes

NOTES NOTES ARENAVIRIDAE MICROBE OVERVIEW Taxonomy ▪ Zoonotic virus family ▫ Associated with hemorrhagic fevers, meningoencephalitis ▪ Comprises > 20 viruses ▪ Groups ▫ Old World viruses (e.g. lymphocytic choriomeningitis virus, Lassa, Lujo) ▫ New World viruses (e.g. Junin, Machupo) Morphology ▪ Single-stranded RNA virus ▪ Ribosomes produce sand-like granular appearance under electron microscopy ▫ Latin: arena = sand ▪ Shape varies: pleomorphic–spherical ▪ Enveloped in lipid membrane with glycoprotein spikes ▫ Lipids in membrane → inactivation susceptibility by organic solvents/ detergents ▫ Also inactivated by temperatures > 55°C/131°F, ↑ ↓ pH, UV light, gamma irradiation Transmission ▪ Reservoir ▫ Rodents shed virus in urine, feces, saliva, nasal secretion ▪ Transmission ▫ Ingestion, direct contact, aerosolizedparticle inhalation → entry into cell by GP1 glycoprotein attachment to cellular receptors → systemic dissemination LYMPHOCYTIC CHORIOMENINGITIS VIRUS (LCMV) osms.it/LCMV PATHOLOGY & CAUSES ▪ Arenavirus ▫ Causes febrile illness with central nervous system (CNS) involvement, congenital infection ▪ Reservoir ▫ Mice (M. musculus/M. domesticus); occasional human disease outbreak related to pet hamster/guinea pig ▪ Transmission ▫ Ingestion, aerosolized-particle inhalation, transplacentally (infected mother → fetus) ▪ Post-transmission → 7–14 days incubation → replication in lungs → hematogenous dissemination → strong neurotropism (infects meninges, choroid plexus, ventricular ependyma) RISK FACTORS ▪ Infected rodent contact; dwelling/working in rodent habitats ▪ ↑ risk in substandard housing (e.g. mobile homes, inner-city housing), barns/ OSMOSIS.ORG 325

outbuildings ▪ Peak incidence: autumn, winter COMPLICATIONS ▪ Encephalitis, aseptic meningitis ▪ Transplacental infection: spontaneous abortion, neonatal neurologic deficits, chorioretinitis, seizures, periventricular calcifications, hydrocephalus, microcephaly ▪ Rarely: orchitis, parotitis, myocarditis SIGNS & SYMPTOMS ▪ May be asymptomatic/mild flu-like symptoms ▪ Prodrome: headache (retro-orbital), nausea, vomiting ▪ Meningitis: fever, rigors, malaise, myalgia, arthralgia anorexia, photophobia ▪ Encephalitis: focal seizures, cranial nerve palsies, papilledema 326 OSMOSIS.ORG DIAGNOSIS LAB RESULTS ▪ Cerebrospinal fluid (CSF) ▫ ↑ lymphocytes, ↑ protein, ↓ glucose, negative Gram stain Microbe identification ▪ Viral culture, polymerase chain reaction (PCR) Serology ▪ ↑ antibody titer (IgM, IgG) TREATMENT OTHER INTERVENTIONS Prevention ▪ Rodent control