Bunyaviruses Notes

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Osmosis High-Yield Notes

This Osmosis High-Yield Note provides an overview of Bunyaviruses essentials. All Osmosis Notes are clearly laid-out and contain striking images, tables, and diagrams to help visual learners understand complex topics quickly and efficiently. Find more information about Bunyaviruses:

Hantavirus

NOTES NOTES BUNYAVIRUSES MICROBE OVERVIEW ▪ Bunyaviruses: RNA virus order ▪ AKA Bunyavirales Genetic material ▪ Negative-sense, single-stranded RNA ▪ Tripartite genome ▫ Large (L) segment (encodes RNApolymerase); medium (M) segment (encodes surface glycoproteins); small (S) segment (encodes nucleocapsid proteins) Morphology ▪ Enveloped (outer lipid membrane) ▪ Spherical ▪ Size: 90–100nm Replication ▪ Host cytoplasm replication Transmission ▪ Vector-borne, person-to-person, contact with reservoir (species-dependent) ▪ Reservoirs: arthropods, mammals (especially rodents Figure 58.1 Families of the Bunyavirus order and associated clinical syndromes. OSMOSIS.ORG 327
HANTAVIRUS osms.it/hantavirus PATHOLOGY & CAUSES ▪ Single-stranded RNA virus genus → causes severe renal/pulmonary disease ▪ AKA Orthohantavirus ▪ Hantaviridae family ▪ Reservoir ▫ Rodents (mice, voles, shrews, rats) ▪ Incubation period ▫ 9–33 days ▪ Tissue tropism ▫ Lymphoid organ, heart, lung, kidney vascular endothelium ▪ Hantavirus inhalation → lung phagocytosis → transport to lymph nodes → hantavirus enters epithelial cells using beta-3 integrins → ↑ vascular permeability → dissemination ▪ Immune response ▫ CD4+/CD8+ cytotoxic T cells, dendritic cells ▪ High-prevalence regions ▫ China, Russia, Europe Associated clinical syndromes ▪ Hemorrhagic fever + renal syndrome (“Old World” AKA Asia, Europe) 328 OSMOSIS.ORG ▪ ↑ vascular permeability → ↓ blood pressure → kidney endothelial dysfunction ▪ Hantavirus cardiopulmonary/pulmonary syndrome (“New World” AKA North, South America) ▪ ↑ vascular permeability → non-cardiogenic pulmonary edema CAUSES ▪ Rodents (urine/feces/saliva particle inhalation); person-to-person (rare) RISK FACTORS ▪ ▪ ▪ ▪ Rural indoor spaces (e.g. barns) Wild rodent exposure Smoking → Puumala virus infection risk ↑ risk among biological males COMPLICATIONS ▪ Cardiogenic shock, pulmonary edema, arrhythmia, renal insufficiency, acute kidney injury (AKI), coagulopathy, disseminated intravascular dissemination (DIC), hemorrhage; high mortality rate
Chapter 58 Bunyaviruses SIGNS & SYMPTOMS Urinalysis ▪ Renal syndrome: proteinuria, hematuria Pulmonary syndrome ▪ Systemic ▫ Fever, chills, myalgia, headaches, weakness ▪ Nausea, vomiting, diarrhea, abdominal pain, cough, oliguria ▪ Sometimes conjunctivitis, flushing, petechiae Tissue biopsy ▪ Kidneys: edema, perirenal hemorrhage, tubular destruction ▪ Lungs: edema, mononuclear cell infiltrates, tracheal/pleural fluid, hyaline deposits ▪ Lymphoid organs: mononuclear cell infiltrates Hemorrhagic fever + renal syndrome ▪ Fever, hypotension, malaise, headache, diffuse hemorrhage (e.g. petechiae, melena, ecchymoses), abdominal/loin pain, nausea/ vomiting, oliguria TREATMENT DIAGNOSIS DIAGNOSTIC IMAGING Chest X-ray ▪ Lungs: bilateral pulmonary infiltrates, pleural effusion Abdominal ultrasound ▪ Kidneys: ↑ size, perirenal fluid LAB RESULTS MEDICATIONS ▪ Renal syndrome antivirals ▫ Nucleoside analogue OTHER INTERVENTIONS ▪ ICU monitoring, mechanical ventilation ▪ Severe cases ▫ Extracorporeal membrane oxygenation (ECMO), dialysis, platelet transfusion Prevention ▪ Potential rodent nesting site removal (e.g. debris, garbage) ▪ Closed spaces ventilation ▪ Avoid rodent contact ▪ Reverse-transcriptase polymerase chain reaction (RT-PCR) Tests ▪ Diagnostic triad: thrombocytopenia, ↑ immunoblasts (> 10%), left-shifted granulocytic series ▪ ↑ lactate dehydrogenase (LDH), serum lactate ▪ ↑ liver enzymes ▪ ↑ C-reactive protein ▪ Severe ▫ ↑ hemoglobin, hematocrit; ↓ albumin; altered coagulation tests ▪ Renal syndrome ▫ ↑ serum creatinine, ↓ glomerular filtration rate (GFR) Serologic tests ▪ IgM/IgG detection through ELISA, strip immunoblot, Western blot, immunofluorescence OSMOSIS.ORG 329

Osmosis High-Yield Notes

This Osmosis High-Yield Note provides an overview of Bunyaviruses essentials. All Osmosis Notes are clearly laid-out and contain striking images, tables, and diagrams to help visual learners understand complex topics quickly and efficiently. Find more information about Bunyaviruses by visiting the associated Learn Page.