1. Arboviruses and other zoonotic viruses
Arbovirus: Arthropod-borne Viruses  maintained  in nature principally, or  to  an  important extent,  through  biological  transmission  beten   susceptible vertebrate  hosts by haematophagus arthropods or through  transovarian and possibly venereal transmission in arthropods

2. ARBOVIRUSES FAMILY ENVELOPE yes no SYMMETRY icosahedral helical GENOME
ssRNA (+ve)
ssRNA (-ve)
segmented
dsRNA,

3. Transmission Cycles Man - arthropod -man
e.g. dengue, urban yellow fever.
Reservoir may be in either man or arthropod vector.
In the latter transovarial transmission may take place.
Animal - arthropod vector - man
e.g. Japanese encephalitis, EEE, WEE, jungle yellow fever.
The reservoir is in an animal.
The virus is maintained in nature in a transmission cycle involving the arthropod vector and animal. Man becomes infected incidentally.
Both cycles may be seen with some arboviruses such as yellow fever.

4. Man-Arthropod-Man Cycle

5. Animal-Arthropod-Man Cycle

7. Arthropod Vectors Mosquitoes Ticks Sandflies
Japanese encephalitis, dengue, yellow fever, St. Louis encephalitis, EEE, WEE, VEE etc.
Ticks
Crimean-Congo haemorrhagic fever, various tick-borne encephalitides etc.
Sandflies
Sicilian sandfly fever, Rift valley fever.

10. Examples of Arthropod Vectors
Aedes Aegyti
Assorted Ticks
Phlebotmine Sandfly
Culex Mosquito

11. Overwintering ability Transovarial transmission VERTEBRATE
ARTHROPOD
Habitat
Diurnal activity
Preferred host
Annual activity
Overwintering ability
Transovarial transmission
VERTEBRATE
Migratory activity
Persistence of viremia
Clinical consequences
Reservoir ?
Dead end host?
At least 150 species mosquito in US alone.
~3500 species worldwide

12. Prevention Surveillance - of disease and vector populations
Control of vector - pesticides, elimination of breeding grounds
Personal protection - screening of houses, bed nets, insect repellants
Vaccination - available for a number of arboviral infections e.g. Yellow fever, Japanese encephalitis, Russian tick-borne encephalitis

15. ARBOVIRAL DISEASE INITIAL VIRAL REPLICATION INTERFERON (RNA VIRUSES)
All are cytolytic
endothelial cells
macrophages/monocyte lineage
INTERFERON (RNA VIRUSES)
headache, fever, myalgia (flulike)
VIREMIA
spread to target tissues, depending on tropism of virus
Role of innate immunity in disease progression
Non-neutralizing Ab  may enhance flavivirus infection via Fc receptors on macrophages

16. RECOVERY INTERFERON CELL-MEDIATED IMMUNITY
ANTIBODY MAY PLAY A ROLE IN PREVENTING SPREAD DURING VIREMIC PHASE

17. Flaviviruses Spherical, 40-60 nm Positive sense, 11 kb ssRNA
3 structural proteins
Replication and essembly in cell cytoplasm

19. Yellow Fever West Africa and South America
Jungle YF is the natural reservoir of the disease in a cycle involving nonhuman primates and forest mosquitoes. Man may become incidentally infected on venturing into jungle areas.
The urban form is transmitted between humans by the Aedes aegypti mosquito
Some patients may experience an asymptomatic infection or a mild undifferentiated febrile illness.

20. Mild illness: Fever, headache, pink eye
Severe illness (%15 of the infected): Fever, chills, naussea, vomiting (vomitus negra), severe mylagia, lower back pain,yellow colorination of the sklerae (due to hepatic involvement), hemoorhagia, anuria, death

21. Yellow Fever
After a period of 3 to 4 days, the more severely ill patients with a classical YF course will develop bradycardia (Faget's sign), jaundice, and haemorrhagic manifestations.
50% of patients with frank YF will develop fatal disease characterized by severe haemorrhagic manifestations, oliguria and hypotension.
Diagnosis is usually made by serology
There is no specific antiviral treatment
An effective live attenuated vaccine is available against yellow fever and is used for persons living in or traveling to endemic areas.

22. Yellow Fever
50% of patients with frank YF  fatal disease with severe haemorrhagic manifestations, oliguria and hypotension
Diagnosis is usually made by serology, molecular detection
There is no specific antiviral treatment
Live attenuated vaccine  persons living in or traveling to endemic areas.

24. West Nile virus Japanese encephalitis virus antigenic complex
(Japanese encephalitis, St. Louis encephalitis, Murray Valley encephalitis, and Kunjin)

25. 80% asymptomatic In 20 % Fever Headache Fatigue
Skin rash on the trunk of the body (occasionally)
Swollen lymph glands (occasionally)
Eye pain (occasionally)

26. In 1/150 cases Fever Gastrointestinal symptoms
Ataxia and extrapyramidal signs
Optic neuritis
Seizures
Weakness
Change in mental status
Myelitis
Polyradiculitis
A minority of patients with severe disease develop a maculopapular or morbilliform rash involving the neck, trunk, arms, or legs.
Flaccid paralysis is sometimes seen.
Although not observed in recent outbreaks, myocarditis, pancreatitis, and fulminant hepatitis have been described.

29. Dengue Fever Vector: Aedes ; epidemic (> 100 countries)
Incubation period: 3-14 days (usually 4-7d)
4 serotypes called DENV-1, -2, -3, and -4
Three clinical presentation
Undifferentiated Fever;
Dengue Fever with or without hemorrhage; or
Dengue Hemorrhagic Fever or Dengue Shock Syndrome.

37. Bunyavirideae Nairovirus Ortho Bunyavirus Bunyavirus Hantavirus
Phlebovirus
Phlebovirus
Hantavirus
Nairovirus
Tospovirus
Tospovirus
7 serogroups;
CCHF Grubu:
CCHFv*
Dugbe*
Nairobi koyun hastalığı virusu*
Hazara (Patojen değil)

38. Segmented ss RNA virus
L, S and M segments

39. Tick vectors Hyalomma truncatum Hyalomma marginatum
Hyalomma impeltatum
Hyalomma impressum
Amblyomma variegatum
Boophilus decolaratus

43. CCHF: transmission Tick bite Crushing of ticks
Contact with viremic animal’s carcasses
Nosocomial
Patient contact
Tissue & body fluids contact
Laboratory

44. Incubation: - Following tick bite 1-3 d; max. 9 days,
- Following exposure to infected blood, tissue or body fluids 5-6 days: max. 13 days

45. Clinical course Human Animals Flu like signs Haemorrhagies + DIC…
Death (10-80%)
Animals
No disease
Temparate fever…
Viremia max. 10 days

46. Symptoms n (%) Fatigue 86 (94) Fever 84 (91) Myalgia 83 (90)
Head ache (80)
Sore throat (20)
Gastrointestinal
Naussea (75)
Vomiting (68)
Diarrhea (39)

47. Prehemorrhagic period
PLTs
Incubation
3-7 days
Prehemorrhagic period
1-7 days
Hemorrhagic period
2-3 days
Convelescence
Bleeding from various sites
(hematemesis, melena, etc.)
somnolence
AST
ALT
WBCs
Fatality happens
Polymerase Chain Reaction: The first 9 days
Myalgia,
Fever,
Nausea-vomiting
Diarrhea
7 d
10 d
days
DIC
IgM (7 days-4 months) and IgG (7 days-5 years)
viremia
Ergonul O. Lancet ID 2006; 6:

50. :150 cases; 4.5% fatality
2004: 249 cases; 5.2% fatality
2005: 266 cases; 5% fatality
2006: 224 cases.....
The largest epidemic in the World

52. Hantavirus
Distinct hantaviruses are associated with specific rodent hosts.
Cause hemorrhagic fever with renal syndrome (HFRS) or hantavirus pulmonary sundrome (HPS)
Transmission via: Inhalation of aeresols of rodent excreta

53. hemorrhagic fever with renal syndrome (HFRS)
Interstitiel nephritis  acute renal failure
Genralised hemorrhagia and shock
CFR is 5-15 %
Hantaan and Dobrova viruses in Asia and in Balkans
In Euroasia a mild form  nephropathia epidemica  caused by Puumala virus (Scandinavia)

58. HAntavirus Pulmonary Syndrome (HPS)
First described in 1993 in North America
Sin Nombre virus
Mortality 30 %

59. Sandfly Fever Phlebovirus Vector  Phlebotomus papatasii
Naples virus, Sicilian virus, Cyprus and Toscana virus

61. Arenaviruses Segmented RNA; two ss RNA molecules
Old and new world arenaviruses
Establish chronic infections among rodents
Lassa fever: Africa, most common seqelae is deafness