Dengue and chikungunya 2016
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Dengue and chikungunya are arboviral infections transmitted by Aedes mosquitoes. Dengue is caused by any of four dengue virus serotypes and causes flu-like symptoms. Chikungunya virus causes sudden onset of high fever and severe joint pain. Both illnesses present symptoms within 1 to 12 days of a mosquito bite. Prevention relies on controlling the Aedes aegypti and albopictus mosquito vectors through reducing standing water and using insect repellents.
Dengue and chikungunya 2016
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- 3. Dengue & Chikungunya Viral infections Arbo Viral Infections RNA viruses Prof. Ashok Rattan, MD, MAMS, INSA DFG, WHO Lab Director Academics, Industry: Research, Diagnosis, Public Health, Academics
- 4. Dengue • Of great antiquity, clinically known in China • Swahili “ka dinga pepo” • Along with slaves ; Africa Caribbean • In Cuba (Spanish) Dinga is Dengue (fastidious) • 4 closely related RNA viruses – DEN 1, DEN 2, DEN 3, DEN 4 – Share same geographical & ecological niche – Ss RNA, flavi virus
- 5. Dengue Virus
- 6. Mosquito Transmission: Aedes aegypti and Aedes albopictus
- 7. Transmission: Aedes mosquito • Aedes aegypti – Urban mosquito – Needs standing water for larvae – Prefers cool, dark areas for resting – Feeds through the day, most active at dawn/dusk – Eggs do not survive winter in temperate climates • Aedes albopictus: Asian Tiger Mosquito – Urban, periurban, rural habitats – Feeds through the day, most active dawn/afternoon – Eggs survive winter in temperate climates – Invasive- spreading in Europe and Americas www.cdc.gov
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- 12. Course of Dengue illness
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- 18. Lumsden WH. Trans Roy Soc Trop Med Hyg 1955;49:33-57
- 19. Chikungunya Virus (CHIKV): Alphavirus • “That which bends up” in Swahili • Togaviridae family • Single strand RNA virus, mosquito-transmitted www.cdc.gov/ncidod/dvbid/arbor/alphavir.htm
- 20. 20 What is Chikungunya? • Chikungunya is a virus that is transmitted from human to human mainly by infected Aedes albopictus and Aedes aegypti mosquitoes acting as the disease- carrying vector • Chikungunya causes sudden onset of high fever, severe joint pain, muscle pain and headache – 3 main presentations • Acute: – sudden onset, – Severe, incapacitating polyarthralgia – Maculopapular rash on trunk & extremities • Subacute: – Relapse of symptoms 2 to 3 months following initial infection – Exacerbated pain in previously affected joints • Chronic: – Persistence of arthralgia & fatigue for > 3 months – Prevalence in 12 to 50%
- 21. 21 Symptoms • Symptoms include: Sudden onset of high fever Headache Back pain Myalgia Arthralgia • The symptoms will appear on average 4 to 7 days (but can range from 1 to 12 days) after being bitten by an infected Aedes mosquito
- 22. Mosquito Transmission: Aedes aegypti and Aedes albopictus
- 23. Transmission: Aedes mosquito • Aedes aegypti – Urban mosquito – Needs standing water for larvae – Prefers cool, dark areas for resting – Feeds through the day, most active at dawn/dusk – Eggs do not survive winter in temperate climates • Aedes albopictus: Asian Tiger Mosquito – Urban, periurban, rural habitats – Feeds through the day, most active dawn/afternoon – Eggs survive winter in temperate climates – Invasive- spreading in Europe and Americas www.cdc.gov
- 24. 24 Epidemiology Chikungunya risk zones Outbreaks of Chikungunya virus are usually found in: – Africa – Southeast Asia – Indian subcontinent and islands in the Indian Ocean
- 25. CHIKV: re-emerging disease • Initial descriptions in 1950s • 2000 Epidemic in Kinshasa, DRC, 1st in 39 years • 2001-2003 epidemic in Indonesia, 1st in 20 years • 2004 Coastal Kenya – E226V mutation more efficiently transmitted by Aedes albopictus – 2005 Spread to Comoros Islands • 2005-2007 Epidemic in Réunion: 35% attack rate – 266,000 cases – 0.1% mortality • 2006 Maldives & India • 2008 Singapore • 2012 Rural Cambodia – 44.7% prevalence – 5.3% asymptomatic • 2012 Bhutan – 1st cases reported – Index case recent travel from India – East/Central/South African genotype • 2012 Papua New Guinea – 1st cases reported MMWR 2012; 61: 737-40 www.cdc.gov/eid 2013 vol 19
- 27. Treatment and Prevention • Acute Illness – Supportive care – NSAIDS – Case reports of short steroid courses for severe early disease • Persistent arthralgias: no good data for treatment – Chloroquine, hydroxychloroquine • No sig difference in efficacy for acute arthralgias between chloroquine and meloxicam in 509 indiv in India – Sulfasalazine, methotrexate, ribavirin, interferon-alpha • Mosquito avoidance • Vaccines in research, not licensed • Monoclonal antibodies as prophylaxis effective in mouse models
- 42. 42 What should I do if I suspect my patient has Chikungunya? Chikungunya is a reportable disease. ECDC proposes the following reporting levels: Case categories • Possible case: a patient meeting clinical criteria • Probable case: a patient meeting both the clinical and epidemiological criteria • Confirmed case: a patient meeting the laboratory criteria, irrespective of the clinical presentation
- 43. 43 Algorithm for ascertainment of suspected Chikungunya case Source: ECDC Mission Report: Chikungunya in Italy, Joint ECDC/WHO visit for a European risk assessment 17 – 21 September 2007
- 47. Protection • Personal protection: DEET, Picaridin • Household prevention: Screen, Bed nets • Neighbourhood & community prevention • Vector Control – Same as for Dengue vector control