1 CHIKUNGUNYA FEVER Infection and Tropical Pediatric Division Department of Child Health Medical Faculty, University of Sumatera Utara

2 Synonyms CHIKV Fever Buggy Creek virus infection Knuckle fever Me Tri virus infection Semliki Forest virus infection

3 A common viral fever Self limiting – non fatal illness Fever, myalgia, arthralgia, lasting days

4 CLINICAL EPIDEMIOLOGY

5 A disease of Africa and Asia

6 Asian Distribution

7 Epidemiological Triangle The Host The Virus The Environment Interaction The Vector

8 History (Its story) A viral infection transmitted to humans By the bite of an infected mosquito It has become endemic in south and central India First outbreak in 1952 on the Makonde Plateau Border between Tanganyika and Mozambique First published report is from Africa in 1955 by Marion Robinson and W.H.R. Lumsden Recent large epidemic occurred in Malaysis in 1999

9 What is this virus ? Causative agent is an RNA – VIRUS Class – Arbor Virus (Arthropod Borne) Family – Togaviridae Genus – Alpha Virus Species – Chikungunya Virus Similar to Semliki Forest Viruses (SFV) in Africa and Asia.

10 Chikungunya Virus - EM

11 Transmission Reservoir – Non-human primates in Africa No animal reservoir is found in India Maintained in nature by man – mosquito – man cycle Vector – Aedes aegypti, Ae. albapticus mosquito Same vector as for Dengue and Yellow fevers Vehicle of transmission – None No known mode - other than mosquito bite Incubation Period – 2 days to 12 days

12 The Vector Aedes aegypti mosquito, flight range < 100 meters Aggressive daytime biter – under lights – bites ankles Once infected – it has the virus until death (30 days) It is a man made mosquito – prefers its owner Breeds in man made household containers Indoor, peridomestic, fresh water mosquito Metallic, plastic, rubber, cement and earthen containers - open, left or unused - get filled with water Air coolers, ACs, Old oil drums, Over head tanks

13 Aedes aegypti

14 Aedes albaptycus Tiger Mosquito

15 Madam Aedes - at her Lunch

16 Water tap – A disease trap

17 Open Overhead Tanks

18 Domestic Water Collections

19 Why only Aedes Mosquito ? Scanning Electron Micro- graph of the mid gut cells of the mosquito Location of the Chik Virus binding proteins. Not transmitted to the progeny of the mosquito

20 Most Recent Epidemics Epidemic of CHIKV occurred in Malaysia – 1999 French island of Réunion in the Indian Ocean Epidemic was recorded in Mauritius – 2005 Madagascar, Mayotte and Seychelles – 2005 Hong Kong and Malaysia early 2006 Present indian epidemic is the largest -from Dec ’05

21 Attack Rates In urban localities it is more – why ? Usual age group is above 15 years Less common in children and infants Family clustering of cases usual Attack rates vary from 3 to 40% of population Average attack rate is 10% Herd immunity restricts further spread

22 Symptoms Sudden onset of fever, chills Headache, nausea, vomiting, abdominal pain Joint pain with or without swelling, Low back pain and rash Very similar to those of Dengue but Unlike in Dengue, no hemorrhagic or shock syndrome

23 Clinical Features Incubation period is 2-12 d; usually 3-7 days Viremia last for 5 days (infective period) Silent CHIKV – inapparent infections in children Flu-like symptoms, Severe headache and chills High grade fever (40°C or 104°F), Arthralgia or arthritis – lasting several weeks Conjunctival suffusion and mild photophobia Nausea, vomiting, abd. pain, severe weakness

24 The Arthralgia The small joints of the lower and upper limbs Migratory poly arthralgia – not much effusions Larger joints may also be affected (knee, ankle) Pain worse in the morning – less by evening Joints may be swollen & painful to the touch Some patients have incapacitating joint pains Arthritis may last for weeks or months.

25 Skin Rash in Dengue

26 Skin Rash in CHIKV

27 Rare Clinical Features A petechial or maculo papular rash usually involving the limbs may occur. Hemorrhage is rare Nasal blotchy erythema, freckle-like pigmentation over centro-facial area, Flagellate pigmentation on face and extremities Lichenoid eruption and hyper pigmentation in exposed areas

28 Rare Clinical Features Multiple aphthous-like ulcers over –scrotum, crural areas and axilla Unilateral or bilateral lympoedema of the limbs Lymphadenopathy not common Multiple ecchymotic spots in children Vesiculo-bullous lesions in infants and Sub-ungual hemorrhages Severe menigo-encephalitis – rare; may be fatal

29 Course of Illness Fever typically lasts for days and comes down Fever may reoccur after 3 days – ‘saddle back’ fever Some rare cases - fever lasts up to a couple of weeks Patients do have prolonged fatigue for several weeks High fever & crippling joint pain marked this epidemic Joint pain, intense headache, insomnia and an extreme degree of prostration may last for 5 to 7 days Life long immunity, once one suffers this infection

30 Who are at greater risk ? Pregnant women Elderly people Newborns Women in general Diabetics Immuno-compromised patients Patients with severe chronic illnesses

31 CHIKV Morbidity Chikungunya is a self-limiting illness Causes of prolonged morbidity are –Severe dehydration –Electrolyte imbalance and –Loss of glycemic control Recovery is the rule In about 3 to 5% –Incidence of prolonged arthritis

32 Mortality A few deaths have been reported - Examples It was thought to be due mainly to –Inappropriate use of antibiotics and NSAIDs –Virus can cause thrombocytopenia –These drugs can cause gastric erosions - thus –Leading to fatal upper GI bleed –Use of steroids for the joint pains & inflammation –This is dangerous and completely unwarranted

33 Differential Diagnosis Dengue fever, DHF, DSS O’nyong-nyong viral fever Sindbis viral fever Other non specific viral fevers Any other acute fever like malaria, UTI etc.

34 Differential Diagnosis FeatureCHIKVDENGUE PresentationA+F ± mild rashA+F+Rash ArthralgiaModerateSevere ArthritisNot commonFrequent Bone painsNoneBreak bone fever ThrombocytopeniaMild (Not < 1K)May be severe HemorrhageNoneMay be present Shock syndromeNeverMay occur Immunity (IgG)Life long2 nd attack fatality

35 Laboratory Diagnosis 1.Four fold or more rise of HI Antibody 2.IgM capture ELISA using MAbs 3.Indirect Immuno Flourescence Test (I IFT) –On infected cells from tissues 4.Virus Isolation – Infant Swiss Albino mice –Vero BHK-21 cell lines are used 5.Nucleic acid amplification by PCR & RT PCR

36 Laboratory Diagnosis IgM capture ELISA – Good serological test Not commercially available NIV – Pune, NICD – Delhi only Positive after 5-10 days & lasts up to 6 months HI Antibody appears on day 3 or 4 RT –PCR confirmatory – before the 5 th day

37 Treatment There is no specific treatment for CHIKV No vaccine or preventive pill is available The illness is usually self-limiting It will resolve with time over a week to 10 days No relapses occur – no second attacks Convalescence may take longer Symptomatic treatment only

38 Treatment Rest to the patient and mild movements of joints Cold compresses to inflamed joints Liberal fluid intake or IV fluids Analgesics and NSAIDS –Paraetamol ± Ibuprofen or aceclofenac or diclofenac –Naproxen sodium (Naprasyn, Xenobid) –Aspirin should be avoided Hydroxy chloroquine sulphate (HCQS) 200 mg/od Chloroquine phosphate 250 mg/od

39 What not to give ? No indication for antibiotics Never use costly, large spectrum drugs No indication for long acting steroids No indication for short term steroids also in the acute phase of illness Rarely, if the joint swelling persists – we may consider use of steroids in short burst.

40 Management of cases Rest in bed will help hasten recovery Infected persons should be protected –from further mosquito exposure –staying indoors and/or under a mosquito net –during the first few days of illness –This is to reduce transmission to others

41 Prevention from mosquito bites Use insect repellent such as DEET on exposed skin. Wear long sleeves & pants, treat clothes with permethrin Have secure screens on windows and doors Get rid of mosquito breeding sites by –Emptying standing water from flower pots, buckets etc., –Change the water in pet dishes in bird baths weekly –Drill holes in tire swings so water drains out –Keep children's wading pools empty

42 Perfect Protection

43 Vector Control Measures Cover all tanks, cisterns, barrels, containers Remove old tyres, tins, buckets and bottles Clogged gutters and drains need to be cleared Change water in dip trays, plant pots twice week Tanks need to be covered and cleaned - 2 weeks Weeds and tall grass to be cut short – ↓ hiding Temephos 1 ppm for large water tanks

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