arthropod-borne (arbo) viral diseases
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Arthropod-Borne (Arbo) Viral Diseases - PowerPoint PPT PresentationTRANSCRIPT
Chair of Medical Biology, Microbiology, Virology, and Immunology
Lecturer Prof. S.I. Klymnyuk
Arboviruses
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.
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,
Current taxonomic status of some arbovirusesCurrent Taxonomic
ClassificationArbovirus Members
Bunyaviridae
Genus Bunyavirus
Bunyamwera, Bwamba, C, California, Capim, Guama, Koongol, Patois, Simbu, and Tete; 7 unassigned viruses
Genus Uukuniemi Uukuniemi, 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
Current taxonomic status of some arboviruses
Current Taxonomic Classification
Arbovirus Members
Arenaviridae Genus Arenavirus
Junin, Lassa, Machupo, and Pichinde viruses
Nodaviridae Nodamura virus
Sindbis virus
Structures of Alphaviruses
Principal medically important alphaviruses
Virus Antigenic Clinical
Syndrome
Vector Host Distribution
Eastern equine
encephalitis
Encephalitis (EEE)
Mosquito Birds Americas
Western equine
encephalitis
Encephalitis (WEE)
Mosquito Birds North America
Venezuelan equine
encephalitis
Febrile illness,
encephalitis (VEE)
Mosquito Rodents, horses
Americas
Virus Antigenic Clinical
Syndrome
Vector Host Distribution
Chikunguny (CHIK) Africa,
Febrile illness, rash,
arthralgia
Mosquito Primates, humans
India, Southeast
Asia
O’nyong-nyong (ONN)
Febrile illness, rash,
arthralgia
Mosquito Primates Africa
Sindbisc (SIN)
Febrile illness, rash,
arthralgia
Mosquito Birds Nothern Europe,
Africa, Asia, Australia
Semliki Forest
Febrile illness, rare encephalitis
Mosquito Birds Africa
The scheme of Alphavirus replication
Pathogenesis of alphaviruses
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.
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
Rubella virus
Rash
FIGURE. Clinical findings, virus shedding, and serologic response in postnatally acquired rubella.
Abnormalities Associated with Congenital Rubella Syndrome
Type of defects Examples
Ocular defects Cataracts
Microphthalmia
Glaucoma
Retinitis
Heart defects Patent ductus arteriosus
Atrial septal defect
Ventricular septal defect
Peripheral pulmonic artery stenosis
Hearing impairment Sensorineural deafness
Abnormalities Associated with Congenital Rubella Syndrome
Type of defects Examples
Central nervous system Mental retardation
Meningoencephalitis
Progressive rubella panencephalitis (rare)
Microcephaly
Other Growth retardation
Radiolucent borne disease
Hepatosplenomegaly
Hemathologic abnormalities:
Thrombocytopenia, purpura
Pneumonitis
Endocrine dysfunction:
Insulin dependent diabetes mellitus, thyroididtis
Cataract
Glaucoma
Structure of Flaviviruses
Flavivirus
Tick-born encephalitis virus
Tick-born encephalitis virus
Figure 5. The scheme of Flavivirus replication
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
Virus Antigenic Clinical
Syndrome
Vector Host Distribution
Dengue (DEN)
Febrile illness, rash, hemorrhagic fever, shock syndrome
Mosquito Humans Tropics, worldwide
Yellow fever (YF)
Hemorrhagic fever,
hepatitis
Mosquito Primates, humans
Africa, South America
St. Louis encephalitis (SLE)
Encephalitis Mosquito Birds Americas
Principal medically important flaviviruses
Virus Antigenic Clinical
Syndrome
Vector Host Distribution
Japanese encephalitis
(JE)
Encephalitis Mosquito Pigs, birds India, China, Japan,
South-East Asia
West Nile Febrile illness
Mosquito Birds Africa, Middle East,
Europe
Tick-borne encephalitis (TBE)
Encephalitis Tick Rodent Europa, Asia
Principal medically important flaviviruses
Virus Antigenic Clinical
Syndrome
Vector Host Distribution
Omsk hemorrhagic
fever
Hemorrhagic fever
Tick Muskrats Siberia
Kyasanur Forest disease (KFD)
Hemorrhagic fever
Tick Rodents India primates
Principal medically important flaviviruses
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.
Tick
Yellow fever virus
Yellow fever
Dengue fever virus
Dengue fever
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.
Rift Valley Fever virus
Genus and Group
Virus Disease Vector Distribution
Bunyavirus
Anopheles A Tacaiuma Fever Mosquito South America
Bunyamwera Bunyamwera Fever Mosquito Africa
Germiston Fever Africa
Bwamba Bwamba Fever , Rash
Mosquito Africa
C Apeu Fever Mosquito South America
Human diseases Caused by Viruses of the Family Bunyaviridae
Human diseases Caused by Viruses of the Family Bunyaviridae
Genus and Group
Virus Disease Vector Distribution
Bunyavirus
California California encephalitis
Encepha-litis
Mosquito North America
Snowshoe hare
Encepha-litis
Mosquito North America,
Asia
Tahyna Fever Mosquito Europe
Simbu Shuni Fever Mosquito Africa, Asia
Human diseases Caused by Viruses of the Family Bunyaviridae
Genus and Group
Virus Disease Vector Distribution
Phlebovirus
Phlebovirus fever
Alenquer Fever Unknown South America
Naples Fever Sand fly Europe, Asia, Africa
Rift Valley Fever
Fever, encephalitis, hemorrhagic
fever, blindness
Mosquito Africa
Sicilian Fever Sand fly Europe, Africa, Asia
Human diseases Caused by Viruses of the Family Bunyaviridae
Genus and Group
Virus Disease Vector Distribution
Nairovirus
Crimean-Congo
Crimean-Congo
hemorrhagic fever
Hemorrhagic fever
Tick Africa, Asia
Nairobi sheep disease
Nairobi sheep disease
Fever Tick Africa, Asia
Human diseases Caused by Viruses of the Family Bunyaviridae
Genus and Group
Virus Disease Vector Distribution
Hantavirus
Hataan Hantaan HFRS Rodent Asia
Puumala HFRS Rodent Asia
Sequl HFRS Rodent Asia, Europe
Human diseases Caused by Viruses of the Family Bunyaviridae
Genus and Group
Virus Disease Vector Distribution
Genus unassigned
Bangui Fever, rash Unknown Africa
Bhanja Fever, encephalitis
Tick Africa, Europa, Asia
Issk-kul Fever Tick Asia
Kasokero Fever Unknown Africa
Nyando Fever Mosquito Africa
Tataguine Fever Mosquito Africa
Wanowrie Fever, hemorrhage
Tick Middle East, Asia
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.
FIGURE 5. La Crosse encephalitis transmission cycle
Signs of Crimean-Congo Hemorrhagic Fever
Clinics of Hataan virus infection