HantaVirus

1. HantaVirus By: vivekpatel ROLL #: 1287

2. TABLE OF CONTENTS • Introduction • Replicative cycle • Transmission and epidemiology • Pathogenesis and immunity • Clinical findings • Lab diagnosis • Treatment and prevention

3. introduction • Hantaviruses are emerging viruses which are hosted by small mammals. • Leads to one of two serious illnesses: Hantavirus Pulmonary Syndrome (HPS) and Hemorrhagic Fever with Renal Syndrome (HFRS) • Bunyaviridae family • (-) single stranded enveloped RNA virus.

4. Replicative cycle Attachment of virionparticle to cell's surface through interactions between the cell surface receptors and viral glycoprotein Entry through receptor-mediated endocytosis and uncoatingand release of the viral genomes Transcription of complementary RNA (cRNA) from viral RNA (vRNA) genome using host-derived primers. Translation of L, M, and S mRNAs into viral proteins using host machinery Replication and amplification of vRNA, assembly with the N protein, and transport to Golgi apparatus Assembly of all components at the Golgi apparatus or, possibly for New World viruses, at the plasma membrane Viral egress via fusion of Golgi vesicle harboring the mature virion particles with the plasma membrane

5. Transmission and epidemiology • Exposure to aerosolized urine, droppings, or saliva of infected rodents or after exposure to dust from their nests • Transmission may also occur when infected urine is directly introduced into broken skin or onto the mucous membranes of the eyes, nose, or mouth • First outbreak occurred during the Korean war (1950-1953) where more than 3000 united nations troops were infected with Korean hemorrhagic fever • Increase in number of outbreaks in the Americas • The main known disease burden of hantaviruses in the Old World is HFRS, which caused by Myodes-,Rattus-, and Apodemus-borne hantaviruses, and that in the New World is HPS, which is caused by the sigmodontine-borne hantaviruses. • Old World and New World Hantaviruses.

6. Transmission and epidemiology contd… • For corners virus or Sin Nombre Virus was the name given after 4 regions: Utah, Colorado, New Mexico and Arizona were infected by Hantavirus which caused HPS • Old world hantavirus: hemorrhagic fever with renal syndrome (HFRS) • Also Nephropathia Epidemica (NE) which is a milder form of HFRS which is caused by Puumala virus • there may be as many as 150,000 cases of HFRS each year; more than half occurring in China • New world hantavirus: hantavirus pulmonary syndrome (HPS) is a severe, sometimes fatal, respiratory disease in humans caused by infection with a hantavirus

8. Pathogenesis and immunity • HFRS: 5 Phases: febrile, hypotensive, oliguric, diuretic, and convalescent. • The central physiologic derangement in HFRS is vascular dysfunction, manifested by impaired vascular tone and increased vascular permeability • The systemic effects of this dysfunction account for the occurrence of hypotension and shock, while local effects are probably important in the development of renal failure • Hemorrhage is a consequence of vascular injury and a deficit of functional platelets • Vascular and platelet dysfunction are both compounded by uremia

9. Pathogenesis and immunity contd… • HPS: Immunohistochemistry analysis has shown that viral antigens are distributed primarily within the endothelium of capillaries throughout various tissues from patients with HPS • Electron micrographic studies confirm the infection of endothelial cells and macrophages in the lungs of HPS patients • Functional impairment of vascular endothelium is central to the pathogenesis of HPS

10. Clinical findings • HPS: SHORT FEBRILE PRODROME LASTING 3-5 DAYS. • In addition to fever and myalgias, early symptoms include headache, chills, dizziness, non-productive cough, nausea, vomiting and other GI problems • Typical findings on initial presentation include fever, tachypnea and tachycardia. The physical examination is usually otherwise normal.

11. CLINICAL FINDINGS CONTD… • HFRS: Symptoms of HFRS usually develop within 1 to 2 weeks after exposure to infectious material, but in rare cases, they may take up to 8 weeks to develop. • Initial symptoms begin suddenly and include intense headaches, back and abdominal pain, fever, chills, nausea, and blurred vision.  •  may have flushing of the face, inflammation or redness of the eyes, or a rash. •  Later symptoms can include low blood pressure, acute shock, vascular leakage, and acute kidney failure, which can cause severe fluid overload.

12. Lab diagnosis • Serologic identification of IgM and IgG antibodies to Sin Nombre Virus. • CDC uses an enzyme-linked immunosorbent assay (ELISA) to detect IgM antibodies to SNV and to diagnose acute infections with other hantaviruses. • If a hantavirus infection is suspected, a CBC and blood chemistry should be repeated every 8 to 12 hours. • In severe cases PT, PTT, Fibrinogen and Fibrin split products are elevated.

13. Treatment and prevention • There is no specific treatment or cure for hantavirus infection.  • Appropriate broad spectrum antibiotics while awaiting confirmation of a diagnosis of hps. • Fluids should be administered carefully due to the potential for capillary leakage. • Supplemental oxygen should be administered if patients become hypoxic. • Intravenous ribavirin, a guanosine analogue, has not been shown to be effective for treatment of HPS despite its effects on a related disease, hemorrhagic fever with renal syndrome (HFRS).

15. REFERENCES • http://www.ncbi.nlm.nih.gov/pubmed/24406800 • http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2863364/ • http://www.cdc.gov/hantavirus/hps/index.html • http://www.nytimes.com/health/guides/disease/hantavirus/overview.html