2. Arthropod-Borne (Arbo) Viral Diseases The arthropod-borne viruses, or arboviruses, are a group of infectious agents that are transmitted by blood-sucking arthropods from one vertebrate host to another. They can multiply in the tissues of the arthropod without evidence of disease or damage. The vector acquires a lifelong infection through the ingestion of blood from a viremic vertebrate. All arboviruses have an RNA genome, and most have a lipid-containing envelope and consequently are inactivated by ether or sodium deoxycholate.

4. Current taxonomic status of some arboviruses Current Taxonomic Classification Arbovirus Members Togaviridae Genus Alphavirus Aura, Chikungunya, eastern equine encephalitis, Getah, Maygro, Mucambo, Ndumu, O'Nyong-nyong, Ross River, Semliki Forest, Sindbis, Venezuelan and Western equine encephalitis Flaviviridae Genus Flavivirus Dengue, Israel turkey meningoencephalitis, Japanese B encephalitis, Kunjin, Kyasanur Forest disease, Murray Valley encephalitis, Ntaya. Omsk hemorrhagic fever. Powassan, St. Louis encephalitis, tick- borne encephalitis, Uganda S, Wesselsbron, West Nile fever, yellow fever,

5. Current taxonomic status of some arboviruses Current Taxonomic Classification Arbovirus Members Bunyaviridae Genus Bunyavirus Bunyamwera, Bwamba, C, California, Capim, Guama, Koongol, Patois, Simbu, and Tete; 7 unassigned viruses Genus UukuniemiUukuniemi, Anopheles A, Anopheles B, Bakau, Crimean-Congo hemorrhagic fever, Kaisodi, Mapputta, Nairobi sheep disease, Phlebotomus fever, and Turlock; 8 unassigned viruses Reoviridae Genus Orbivirus African horse sickness, bluetongue, and Colorado tick fever viruses Rhabdoviridae Genus Vesiculovirus Cocal, Hart Park, Kern Canyon, and vesicular stomatitis viruses

6. Current taxonomic status of some arboviruses Current Taxonomic Classification Arbovirus Members Arenaviridae Genus Arenavirus Junin, Lassa, Machupo, and Pichinde viruses NodaviridaeNodamura virus

8. Sindbis virus

9. Structures of Alphaviruses

10. Principal medically important alphaviruses VirusAntigenic Clinical Syndrome VectorHostDistribution Eastern equine encephalitis Encephalitis (EEE) MosquitoBirdsAmericas Western equine encephalitis Encephalitis (WEE) MosquitoBirdsNorth America Venezuelan equine encephalitis Febrile illness, encephalitis (VEE) MosquitoRodents, horses Americas

11. VirusAntigenic Clinical Syndrome VectorHostDistribution Chikunguny (CHIK) Africa, Febrile illness, rash, arthralgia MosquitoPrimates, humans India, Southeast Asia O’nyong- nyong (ONN) Febrile illness, rash, arthralgia MosquitoPrimatesAfrica Sindbisc (SIN) Febrile illness, rash, arthralgia MosquitoBirdsNothern Europe, Africa, Asia, Australia Semliki Forest Febrile illness, rare encephalitis MosquitoBirdsAfrica

12. The scheme of Alphavirus replication

13. Pathogenesis of alphaviruses

14. FIGURE Alphavirus transmission. Virus abbreviations: Chik, chickungunya; RR, Ross River; May, Mayaro; ONN, O'nyong-nyong; SIN, Sindbis; EEE, eastern equine encephalitis; VEE, Venezuelan equine encephalitis.

15. Rubella (German measles) is a common mild disease characterized by a rash. It affects children and adolescents worldwide and can also affect young adults. When rubella virus infects susceptible women early in pregnancy, it may be transmitted to the fetus and may cause birth defects. Therefore, accurate diagnosis is critical in pregnancy. The rubella virus is a member of the genus Rubivirus in the family Togaviridae. Rubellaviruses

17. Rubella virus

21. Rash

24. FIGURE. Clinical findings, virus shedding, and serologic response in postnatally acquired rubella.

25. Abnormalities Associated with Congenital Rubella Syndrome Type of defectsExamples Ocular defectsCataracts Microphthalmia Glaucoma Retinitis Heart defectsPatent ductus arteriosus Atrial septal defect Ventricular septal defect Peripheral pulmonic artery stenosis Hearing impairmentSensorineural deafness

26. Abnormalities Associated with Congenital Rubella Syndrome Type of defectsExamples Central nervous systemMental retardation Meningoencephalitis Progressive rubella panencephalitis (rare) Microcephaly OtherGrowth retardation Radiolucent borne disease Hepatosplenomegaly Hemathologic abnormalities: Thrombocytopenia, purpura Pneumonitis Endocrine dysfunction: Insulin dependent diabetes mellitus, thyroididtis

28. Cataract

30. Glaucoma

32. Structure of Flaviviruses

33. Flavivirus

34. Tick-born encephalitis virus

36. Figure 5. The scheme of Flavivirus replication

37. Virions are formed in perinuclear regions of the cytoplasm in association with Golgi or smooth membranes (Figure 6). Virions appear within cytoplasmic vacuoles and appear to exit the cell as vacuoles fuse with the plasma membrane. Unlike alphaviruses, no evidence of budding has been seen in flavivirus-infected cells, and the mechanisms of virion assembly and release remain obscure. FIGURE 6. Morphogenesis of flaviviruses

38. VirusAntigenic Clinical Syndrome VectorHostDistribution Dengue (DEN) Febrile illness, rash, hemorrhagic fever, shock syndrome MosquitoHumansTropics, worldwide Yellow fever (YF) Hemorrhagic fever, hepatitis MosquitoPrimates, humans Africa, South America St. Louis encephalitis (SLE) EncephalitisMosquitoBirdsAmericas Principal medically important flaviviruses

39. VirusAntigenic Clinical Syndrome VectorHostDistribution Japanese encephalitis (JE) EncephalitisMosquitoPigs, birdsIndia, China, Japan, South-East Asia West NileFebrile illness MosquitoBirdsAfrica, Middle East, Europe Tick-borne encephalitis (TBE) EncephalitisTickRodentEuropa, Asia Principal medically important flaviviruses

40. VirusAntigenic Clinical Syndrome VectorHostDistribution Omsk hemorrhagic fever Hemorrhagic fever TickMuskratsSiberia Kyasanur Forest disease (KFD) Hemorrhagic fever TickRodentsIndia primates Principal medically important flaviviruses

41. Human infection with both mosquito-borne and tick-borne flaviviruses is initiated by deposition of virus through the skin via the saliva of an infected arthropod (Fig 7). Figure 7. Pathogenesis of flaviviruses.

42. Tick

44. Yellow fever virus

45. Yellow fever

47. Dengue fever virus

48. Dengue fever

51. Bunyaviridae is a family of arthropod-borne or rodent-borne, spherical, enveloped RNA viruses. Bunyaviruses are responsible for a number of febrile diseases in humans and other vertebrates. They have either a rodent host or an arthropod vector and a vertebrate host.

54. Rift Valley Fever virus

55. Genus and Group VirusDiseaseVectorDistribution Bunyavirus Anopheles ATacaiumaFeverMosquitoSouth America Bunyamwera FeverMosquitoAfrica GermistonFeverAfrica Bwamba Fever, Rash MosquitoAfrica CApeuFeverMosquitoSouth America Human diseases Caused by Viruses of the Family Bunyaviridae

56. Genus and Group VirusDiseaseVectorDistribution Bunyavirus CaliforniaCalifornia encephalitis Encepha- litis MosquitoNorth America Snowshoe hare Encepha- litis MosquitoNorth America, Asia TahynaFeverMosquitoEurope SimbuShuniFeverMosquitoAfrica, Asia

57. Human diseases Caused by Viruses of the Family Bunyaviridae Genus and Group VirusDiseaseVectorDistribution Phlebovirus Phlebovirus fever AlenquerFeverUnknownSouth America NaplesFeverSand flyEurope, Asia, Africa Rift Valley Fever Fever, encephalitis, hemorrhagic fever, blindness MosquitoAfrica SicilianFeverSand flyEurope, Africa, Asia

58. Human diseases Caused by Viruses of the Family Bunyaviridae Genus and Group VirusDiseaseVectorDistribution Nairovirus Crimean- Congo Crimean- Congo hemorrhagic fever Hemorrhagic fever TickAfrica, Asia Nairobi sheep disease FeverTickAfrica, Asia

59. Human diseases Caused by Viruses of the Family Bunyaviridae Genus and Group VirusDiseaseVectorDistribution Hantavirus HataanHantaanHFRSRodentAsia PuumalaHFRSRodentAsia SequlHFRSRodentAsia, Europe

60. Human diseases Caused by Viruses of the Family Bunyaviridae Genus and Group VirusDiseaseVectorDistributi on Genus unassigned BanguiFever, rashUnknownAfrica BhanjaFever, encephalitis TickAfrica, Europa, Asia Issk-kulFeverTickAsia KasokeroFeverUnknownAfrica NyandoFeverMosquitoAfrica TataguineFeverMosquitoAfrica WanowrieFever, hemorrhage TickMiddle East, Asia

61. FIGURE 3. Pathogenesis of bunyavirus infections. Humans are dead-end hosts of most bunyaviruses; however, the blood of Crimean-Congo hemorrhagic fever patients may be highly infectious.

62. FIGURE 5. La Crosse encephalitis transmission cycle

63. Signs of Crimean-Congo Hemorrhagic Fever

64. Clinics of Hataan virus infection