CHIKUNGUNYA FEVER

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Infection and Tropical Pediatric Division

Department of Child Health

Medical Faculty, University of Sumatera Utara

Synonyms

• CHIKV Fever

• Buggy Creek virus infection

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• Knuckle fever

• Me Tri virus infection

• Semliki Forest virus infection

• A common viral fever

• Self limiting – non fatal illness

• Fever, myalgia, arthralgia, lasting 2 - 7 days

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• Fever, myalgia, arthralgia, lasting 2 - 7 days

CLINICAL EPIDEMIOLOGY

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CLINICAL EPIDEMIOLOGY

A disease of Africa and Asia

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Asian Distribution

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Epidemiological Triangle

The EnvironmentThe Vector

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The HostThe Virus

Interaction

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

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• 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

What is this virus ?

• Causative agent is an RNA – VIRUS

• Class – Arbor Virus (Arthropod Borne)

• Family – Togaviridae

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• Family – Togaviridae

• Genus – Alpha Virus

• Species – Chikungunya Virus

• Similar to Semliki Forest Viruses (SFV) in Africa and Asia.

Chikungunya Virus - EM

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Transmission

• Reservoir – Non-human primates in Africa

• No animal reservoir is found in India

• Maintained in nature by man – mosquito – man cycle

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• 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

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)

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• 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

Aedes aegypti

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Aedes albaptycus

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Tiger Mosquito

Madam Aedes - at her Lunch

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Water tap – A disease trap

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Open Overhead Tanks

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Domestic Water Collections

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Why only Aedes Mosquito ?

• Scanning Electron Micro-graph of the mid gut cells of the mosquito

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of the mosquito

• Location of the Chik Virus binding proteins.

• Not transmitted to the progeny of the mosquito

Most Recent Epidemics

• Epidemic of CHIKV occurred in Malaysia – 1999

• French island of Réunion in the Indian Ocean- 2005

• Epidemic was recorded in Mauritius – 2005

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• 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

Attack Rates

• In urban localities it is more – why ?

• Usual age group is above 15 years

• Less common in children and infants

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• 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

Symptoms

• Sudden onset of fever, chills

• Headache, nausea, vomiting, abdominal pain

• Joint pain with or without swelling,

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• 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

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

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• 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

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)

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• 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.

Skin Rash in Dengue

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Skin Rash in CHIKV

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Rare Clinical Features

• A petechial or maculo papular rash usually

involving the limbs may occur.

• Hemorrhage is rare

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• 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

Rare Clinical Features

• Multiple aphthous-like ulcers over

– scrotum, crural areas and axilla

• Unilateral or bilateral lympoedema of the limbs

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• 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

Course of Illness

• Fever typically lasts for 2 - 3 days and comes down

• Fever may reoccur after 3 days – ‘saddle back’ fever

• Some rare cases - fever lasts up to a couple of weeks

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• 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

Who are at greater risk ?

• Pregnant women

• Elderly people

• Newborns

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• Newborns

• Women in general

• Diabetics

• Immuno-compromised patients

• Patients with severe chronic illnesses

CHIKV Morbidity

• Chikungunya is a self-limiting illness

• Causes of prolonged morbidity are

– Severe dehydration

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– Severe dehydration

– Electrolyte imbalance and

– Loss of glycemic control

• Recovery is the rule

• In about 3 to 5%

– Incidence of prolonged arthritis

Mortality

• A few deaths have been reported - Examples

• It was thought to be due mainly to

– Inappropriate use of antibiotics and NSAIDs

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– 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

Differential Diagnosis

• Dengue fever, DHF, DSS

• O’nyong-nyong viral fever

• Sindbis viral fever

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• Sindbis viral fever

• Other non specific viral fevers

• Any other acute fever like malaria, UTI etc.

Differential Diagnosis

Feature CHIKV DENGUE

Presentation A+F ± mild rash A+F+Rash

Arthralgia Moderate Severe

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Arthritis Not common Frequent

Bone pains None Break bone fever

Thrombocytopenia Mild (Not < 1K) May be severe

Hemorrhage None May be present

Shock syndrome Never May occur

Immunity (IgG) Life long 2nd attack fatality

Laboratory Diagnosis

1. Four fold or more rise of HI Antibody

2. IgM capture ELISA using MAbs

3. Indirect Immuno Flourescence Test (I IFT)

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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

Laboratory Diagnosis

• IgM capture ELISA – Good serological test

• Not commercially available

• NIV – Pune, NICD – Delhi only

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• 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 5th day

Treatment

• There is no specific treatment for CHIKV

• No vaccine or preventive pill is available

• The illness is usually self-limiting

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• 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

Treatment

• Rest to the patient and mild movements of joints

• Cold compresses to inflamed joints

• Liberal fluid intake or IV fluids

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• 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

What not to give ?

• No indication for antibiotics

• Never use costly, large spectrum drugs

• No indication for long acting steroids

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• 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.

Management of cases

• Rest in bed will help hasten recovery

• Infected persons should be protected

– from further mosquito exposure

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– 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

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

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• 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

Perfect Protection

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Vector Control Measures

• Cover all tanks, cisterns, barrels, containers

• Remove old tyres, tins, buckets and bottles

• Clogged gutters and drains need to be cleared

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• 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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