Mosquito-borne viral infection 1 Human Pathogen 2 Structure and properties of virion Transmission and epidemiology Clinical features Laboratory diagnosis Treatment & control Poonsook Keelapang, Ph.D. Department of Microbiology, Faculty of Medicine, Chiang Mai University
44
Embed
Structure and properties of virion Transmission and ... and epidemiology Clinical features ... DENGUE GUIDELINES FOR DIAGNOSIS,TREATMENT, ... Comprehensive Guidelines for Prevention
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Mosquito-borne viral infection
1
Human Pathogen 2
Structure and properties of virionTransmission and epidemiologyClinical features Laboratory diagnosis Treatment & control
Poonsook Keelapang, Ph.D.Department of Microbiology, Faculty of Medicine,Chiang Mai University
• Viruses that maintained in nature through biological transmission between susceptible vertebrate hosts by hemotophagous arthropods (mosquito, tick, sandfly) or through transovarian and possible sexual transmission in arthropods
• Viruses multiply and produce viremia in vertebrates, multiply in the tissues of arthropods and are passed on to new vertebrate by the bites of arthropods after a period of extrinsic incubation.
2
Arthropod-borne viruses (Arboviruses)
3
1. Plague2. Smallpox3. Crimean ‐ Congo hemorrhagic fever4. West Nile Fever5. Yellow fever6. Lassa fever7. Nipah virus disease8. Marburg virus disease9. Ebola virus disease10. Handra virus disease11. Severe Acute Respiratory Syndrome 12. Middle East Respiratory Syndrome
1. Severe plasma leakage2. Severe hemorrhage3. Severe organ impairment
14
with warning signs
Dengue + Warning signs
without
Severe Dengue
Probable dengueLive in/travel to dengue endemic area. Fever and 2 of the following criteria:• Nausea, vomiting• Rash• Muscle & bone pains• Tourniquet test positive• Leukopenia• Any warning signs
DENGUE GUIDELINES FOR DIAGNOSIS,TREATMENT, PREVENTION AND CONTROL (WHO,2009)
Severe plasma leakage• Shock (DSS)• Fluid accumulation with respiratory distressSevere bleedingSevere organ involvement• Liver: AST or ALT > 1,000 IU/ml
NS1antigen appears as early as day 1 after the onset of the fever and declines to undetectable levels by5–6 days
Dengvaxia® (CYD-TDV)(First approved human vaccine: Mexico, Brazil, Philippines, Thailand)
Clinical efficacy and safety of a novel tetravalent dengue vaccine in healthy children in Asia: a phase 3, randomised, observer-masked, placebo-controlled trial Capeding et al., Lancet 2014; 384:1358-65 22
live recombinant tetravalent dengue vaccine
prME YF17D
0/6/12 month schedule
For use in individuals 9-45 years of age living in endemic areas
23
Zika virus 1947 : First isolated from a sentinel monkey in Zika forest in Uganda 1954 : First report case in human in Nigeria
24
Adapted from https://wwwnc.cdc.gov/travel/files/zika-areas-of-risk.pdf
11947 First documented in monkey in Uganda
1954 First human case in Nigeria
23
2007 Outbreak in Yap185 cases
4
2013Outbreak in French polynesia8510 cases
5 2014Outbreak in New Caledonia114 cases
62014-2016Outbreak in Central and South Americaestimated > 1.5 million cases
25
Zika virus: 1 serotype, 2 lineages (African and Asian)Transmission:
Consequent of Zika virus infection• Asymptomatic : 80%• Symptomatic
– Incubation period: not clear (4-7 days?)– Symptoms: fever, skin rash, conjunctivitis, muscle and joint pain,
malaise and headache; usually mild and last for 2-7 days– Complications:
• Guillain-Barré syndrome• Zika virus infection during pregnancy may cause congenital brain
abnormalities such as microcephaly, metal retardation, and visual and auditory impairment; greatest risk if mother is infected during the first trimester
- Live-attenuated, chimeric JEV/YFV vaccine (IMOJEV): propagated in Vero cells ; 95% protection
Prevention and control
Outbreak of West Nile Virus in the US.
34http://wwwnc.cdc.gov/eid/images/05-0289a-F1.gif
New York
West Nile Virus (first detected in Uganda 1937)(Middle East, Australia, Africa, Europe, America)
• Vector: Culex ssp. Reservoir: Bird
• Incidental hosts: human, horse
• Asymptomatic: 80%
• West Nile fever: fever, vomiting, skin rash with swollen lymph glands
• West Nile encephalitis (1 in 150): high fever, neck stiffness, disorientation, coma, tremors, convulsions, muscle weakness and paralysis. High risk: elderly (> 50 years) and immunocompromised persons (mortality rate: 3-15%)
• IgM antibody-capture ELISA (CSF, serum), no vaccine35
Family Togaviridae (toga=cloak)2 Genera: Alphavirus, Rubivirus
• E1 spikes act as attachment proteins, induce neutralizing activity and possess hemagglutinating activity
• Replicates in cytoplasm
E1(59 kDa)
E2C
• An enveloped, icosahedral RNA virus (70 nm in diameter) with a linear single-stranded, positive-sense RNA (11.8 kb)
36
37
Major geographicdistribution
Primary vector
Reservoir Disease
Eastern Equine Encephalitis virus
North America Culex,Anopheles
Birds Encephalitis (mortality rate 30‐70%)
Western Equine Encephalitis virus
North America Culex,Anopheles
Reptile,(Bird?)
Encephalitis(mortality rate 3‐7%)
Venezuelan Equine Encephalitis virus
Central and SouthAmerica
Culex,Anopheles
Rodents Encephalitis
Chikungunya virus Africa, Asia Aedes Human Fever + rash + arthralgia
Onyong‐nong virus Africa Anopheles ? Fever + rash + arthralgia
Ross River virus Australia Culexannulirostris
Kangaroo, wallabies
Fever + rash + arthralgia
Mayaro virus South America Haemagogous Monkeys Febrile illness
Alphaviruses
Chikungunya virus (G. Alphavirus)(Makonde )= that which bends up
• First isolated in 1952 from the serum of a febrile patient during a dengue epidemic in Tanzania (Lumsden, 1955).
38
3 genotypes: West African, Asian, East-Central-South African
Weaver et al., N Engl J Med 2015;372:1231-9.
Transmission - mainly through mosquito bites
Viremia persistsfor upto 5 days (up to 109 copies/ml)
Madariaga et al., Braz J Infect Dis 2016;20:91-8.
Extrinsic incubation period:7- 10 days
39
Others: rodent, birdPrimary reservoir: human
40Couderc T & Lecuit M. Antiviral Research 2015;121:120–131.
Pathogenesis
Outcome of chikungunya virus infection• Asymptomatic infection: 3-25%• Incubation: 2-4 days (range 1-12 days)• High fever (>39°C), arthralgia (joint pain), headache, rash,
back pain, myalgia, nausea, vomiting and photophobia
• Migratory polyalthalgia, bilateral and symmetric. Most commonly in hands and feet joints. Joint swelling.
WHO SEAROBurt et al., Lancet 2012; 379: 662–71
41
Infant (intrapartum transmission): neurologic disease, hemorrhagic symptoms, and myocardial disease
50-60% persistent joint pains for months or years
Case fatality rate = 1:1000
42
Schwartz O & Albert ML. Nature Reviews Microbiology 2010; 8: 491-499.
Diagnosis• Virus isolation: < 3 days• Genome detection (RT-PCR): < 8 days• Anti-CHIKV IgM: > 5 days, peak at weeks 3 - 5 after the onset of
illness and persist for about 2 months• Anti-CHIKV IgG: (paired sera) 4 fold rising titer by HI or ELISA no specific treatment no vaccine
43
Bunyaviruses
• Enveloped RNA virus (Ø 100-120 nm)
• Tripartite, linear negative-sense ssRNA genome
Major geographicdistribution
Primary vector
Reservoir Disease
California encephalitis virus
North America Aedesmelanimon
Rodent Encephalitis
Bunyamwera Africa Aedes Rodent, rabbit Febrile illness
La Crosse America (Midwestern states)
Aedestriseriatis
Rodent Encephalitis(Mortality rate 1%)
Rift Valley fever Africa Aedes Sheep, Cattle Hemorrhagic fever (Mortality rate 50%)
Crimean ‐ Congo hemorrhagic fever Africa, Asia , Europe Tick