Transcript Chikungunya by Dr Sarma

Updated until 23rd September 2006
CHIKUNGUNYA FEVER
Dr. R.V.S.N.Sarma., M.D., M.Sc., (Canada)
Consultant Physician and Chest Specialist
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What is this tongue twister ?
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It is CHIKUNGUNYA
To be pronounced as [chick’-en-GUN-yah]
It is not written as CHICKEN GUINEA
Nothing to do with chicken or mutton eating
Derived from the Makonde verb - Kun gunyala
In Swahili it means ‘to become contorted’ or
More specifically as ‘that which bends up’
• Refers to the stooped posture of the patient
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Synonyms
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CHIKV Fever
Buggy Creek virus infection
Knuckle fever
Me Tri virus infection
Semliki Forest virus infection
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Blessed are we !!
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This is not a Dengue epidemic !
This is not the SARS which stole all the show !!
This is not Bird-Flu hitting Indian economy !!!
This is not the Plague epidemic which threatened
to sweep our country !!!!
• Above all - it is not like HIV or Hepatitis B !!!!!
• This is a self limiting, non fatal viral illness –
Thanks to the Almighty
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Should we be panicky ?
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A common viral fever
Self limiting – non fatal illness
Fever, myalgia, arthralgia, lasting 2 - 7 days
Should give big name for it and be panicky ?
Should create such media hype and chaos ?
Above all, should we politicize to this extent?
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CLINICAL EPIDEMIOLOGY
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A disease of Africa and Asia
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Asian Distribution
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Epidemiological Triangle
The Environment
The Vector
Interaction
The Virus
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The Host
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History (Its story)
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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
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The CHIK Virus
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What is this virus ?
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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.
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Chikungunya Virus - EM
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Transmission
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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
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The Vector
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The Vector
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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
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Aedes aegypti
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Aedes albaptycus
Tiger Mosquito
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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 Micrograph of the mid gut cells
of the mosquito
• Location of the Chik Virus
binding proteins.
• Not transmitted to the
progeny of the mosquito
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The Recent Epidemics
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Notable Outbreaks
• 1963 to 1965 - An epidemic was reported in Calcutta –
• 4.37% of the people were later found to be
seropositive
• 1973 – An epidemic 37.53% in Barsi - Sholapur district
• 2006 – Present epidemic after 33 years is the largest
• 9,06,360 or more cases in Andhra Pradesh
• 5,43,286 cases from Karnataka; 66,109 from B’lore
• Maharashtra 2,02,114 cases; Gujarat 2,500 cases
• Tamil Nadu 49,567 cases; Orissa 4,904 cases,
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• Madhya Pradesh 43,784 and Pune 138 cases
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Distribution in India
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The disease is common with periodic epidemics
Sporadic outbreaks described in Madras and Vellore
Cases were reported in Chennai, Pondicherry, Vellore
Vizag in 1964; Rajahmundri, Kakinada, Nagpur in 1965
The last epidemic in India was in 1973
From Yavat village (Pune) in 2000
2.9% in the Andaman & Nicobar Islands are seropositive
Infected mosquitoes seen in Pune, Maharastra State
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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
• Madagascar, Mayotte and Seychelles – 2005
• Hong Kong and Malaysia early 2006
• Present indian epidemic is the largest -from Dec ’05
• Maximum # of cases from Andhra Pradesh so far
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The Indian Epidemic
• Present epidemic has started in Nov 2005
• Andhra Pradesh, Karnataka, Maharashtra,
Madhya Pradesh, Orissa, Gujarat, Tamilnadu,
Rajasthan, Kerala are under its onslaught
• This is spreading far and wide at a rapid rate
• Not much spread to the northern states like
Delhi, Haryana, Punjab as yet.
• Not much cry from U.P. and Bihar
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Attack Rates
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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
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Why is this sudden epidemic ?
Analysis of the recent Indian epidemic has
suggested that the increased severity of the
disease is due to a change in the genetic
sequence, altering the virus’ coat protein,
which potentially allows it to multiply more
easily in mosquito cells*.
*http//medicine.plosjournals.org
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Why is this quasi-pandemic ?
• Several distinct variants of the virus
• A change at position 226 of the E1 coat protein
• This A226V mutation caused the virus to more easily
invade and multiply in the mosquitoes
• Three protein changes in non-structural proteins
– nsP1 (T301I), nsP2 (Y642N), and nsP3 (E460 deletion)
– This mutant virus - from a neonatal encephalopathy case
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Clinical Features
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Symptoms
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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
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Clinical Features
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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
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The Arthralgia
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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.
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Kun gunyala
The Contorted Posture
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Acute CHIKV Fever
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Skin Rash in Dengue
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Skin Rash in CHIKV
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Petechiae on feet
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The Burden of CHIKV
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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
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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
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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
• 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
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Who are at greater risk ?
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Pregnant women
Elderly people
Newborns
Women in general
Diabetics
Immuno-compromised patients
Patients with severe chronic illnesses
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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
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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
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Pregnancy and CHIKV
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Pregnancy and CHIKV
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Mother to fetus transmission can occur
Reported between 3 to 4.5 months of gestation
Maternal IgG develops in 2 weeks after CHIKV
This passes through placenta – confers protection
Intra-partum risk is 48% if mother has viremia
Neonatal infections are very mild; fully recover
No miscarriages or congenital malformations
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Vertical Transmission
Vertical maternal-fetal transmission of the
Chikungunya virus. Ten cases in newborns
among 84 pregnant women
Robillard PY, Boumahni B, Gerardin P, Michault A,
Fourmaintraux A, Schuffenecker I, Carbonnier M,
Djemili S, Choker G, Roge-Wolter M, Barau G.
Pub Med. 2006 May; 35(5 Pt 1):785-8.
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Pregnancy - CHIKV
• June 2005 to Jan 2006, 84 pregnant women with CHIKV
• In 88% cases the newborns are asymptomatic
• 10 newborns had severe attacks, 4 meningo-encephalitis
• 3 with intravascular coagulations; No infants died
• One case of severe intra cerebral hemorrhage
• Had severe thrombocytopenia
• All confirmed by specific serology or PCR or both
• Women had severe intra-partum viremia & fever
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Differential Diagnosis
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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.
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Differential Diagnosis
Feature
Presentation
Arthralgia
Arthritis
Bone pains
Thrombocytopenia
Hemorrhage
Shock syndrome
Immunity (IgG)
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CHIKV
A+F ± mild rash
Moderate
Not common
None
Mild (Not < 1K)
None
Never
Life long
DENGUE
A+F+Rash
Severe
Frequent
Break bone fever
May be severe
May be present
May occur
2nd attack fatality
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Laboratory Diagnosis
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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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On infected cells from tissues
4. Virus Isolation – Infant Swiss Albino mice
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Vero BHK-21 cell lines are used
5. Nucleic acid amplification by PCR & RT PCR
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Laboratory Diagnosis
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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 5th day
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Value of RT -PCR
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Real Time PCR scores over conventional PCR
Positive in the phase of viremia – up to 5 days
Transportation of sample to be at 2o to 8o c
It is a confirmatory test with high specificity
Its sensitivity is very high; detects even 1 copy
After the viremia ceases – it will be negative
We do not have the HI Ab or Ig M capture
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Treatment of CHIKV
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Treatment
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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
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CHIKUNGUNYA DRUG
France develops a new drug to treat
"We are confident today that a drug to treat
Chikungunya will be made available and we are
hopeful that this drug will be available at the
very end of this year or at the very start of
2007"
- French Health Minister - Xavier Bertrand
- September 11th 2006
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Treatment
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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
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What not to give ?
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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.
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AYUSH
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A Ayurvedic or Acupuncture
Y Yoga and or Naturopathy
U Unaani
S Siddha
H Homeopathy
No comments on these alternative medicines
If no pathy works, finally
Venkatapathy or Tirupathy
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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
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Pregnancy and Lactation
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NSAIDs in Pregnancy
• Using NSAIDs during early or late stages of
pregnancy is not associated with congenital
anomalies, prematurity, or low birth weight, but
• There is a significant link between NSAID use and
miscarriage in the first trimester.
• In third trimester may cause premature delivery
• Recommend stopping NSAIDS 6 to 8 weeks before
delivery to prevent premature closure of fetal ductus
arteriosus.
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Lactating Women
Q. Can a woman suffering from early signs of
Chikungunya breast feed her month old baby?
A. It is better if you do not. During very early stages
fever there is viremia. And some of the virus may be
present in the breast milk. As in newborns the
immune system is not mature particularly monocytemacrophages system, these cells may not be able to
take care of the ingested virus absorbed through
mucous membranes.
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Answered on 28 August 2006 by Dr. Pradeep Seth
Professor of Virology and Head, Department of Microbiology
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Prevention of Mosquito bite
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Avoid Mosquito Menace
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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
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Perfect Protection
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Vector Control Measures
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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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Correct leaking taps
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Cover overhead tanks
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Domestic Water Collections
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Properly close the garbage bins
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Peri domestic fumigation
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Out door fumigation
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Mosquito Magnet
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IEC Activities
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Awareness of CHIKV
Mass media, TV, Radio, News papers
Awareness of vector and its control
Involvement of NGOs
Special campaigns
Punishment for non-compliance
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