Chikungunya is an arbovirus transmitted by Aedes mosquitoes that causes fever and severe joint pain. It was first isolated in Tanzania in 1952. Major outbreaks have occurred in parts of Africa, Asia, and India. There is no vaccine or treatment, so prevention focuses on avoiding mosquito bites and eliminating mosquito breeding sites. Current research is investigating the origin and evolution of the virus in the Indian Ocean region to better understand recent large epidemics and severe forms of the disease.

1. CHIKUNGUNYACHIKUNGUNYA
Dr.T.V.Rao MDDr.T.V.Rao MD

2. What is ChikungunyaWhat is Chikungunya
 Manifest with Crippling Arthritic disease ofManifest with Crippling Arthritic disease of
sudden onset.sudden onset.
 Name is derived from Swahili –Name is derived from Swahili –
Chikungunya meaning that which bendsChikungunya meaning that which bends
upup
 Virus isolated in 1953 from serum andVirus isolated in 1953 from serum and
Aedes mosquitoes and Culex sppAedes mosquitoes and Culex spp

3. ChikungunyaChikungunya VirusVirus
 Family – TogaviridaeFamily – Togaviridae
 Genus - Alpha virusGenus - Alpha virus
 Chikungunya viral infection manifests withChikungunya viral infection manifests with
febrile illnessfebrile illness

4. Epidemics of ChikungunyaEpidemics of Chikungunya
Large epidemics were recognizedLarge epidemics were recognized
in Transvaal of South Africa,in Transvaal of South Africa,
Zambia, India and South eastZambia, India and South east
Asia, PhilippinesAsia, Philippines..

5. Update - ChikungunyaUpdate - Chikungunya

6. Out Breaks of ChikungunyaOut Breaks of Chikungunya
 Out breaks occur during rainy season withOut breaks occur during rainy season with
increasing densities of Aedes aegyptiincreasing densities of Aedes aegypti
mosquitomosquito
 Mosquitos bites infect the HumansMosquitos bites infect the Humans
 Laboratory acquired infection can alsoLaboratory acquired infection can also
occuroccur

7. Chikungunya a MosquitoChikungunya a Mosquito
transmitted viral infectiontransmitted viral infection

8. Cycle of InfectionCycle of Infection

9. HistoryHistory
 Isolated in Aedes aegypti mosquitoes andIsolated in Aedes aegypti mosquitoes and
man in 1952 in Tanzaniaman in 1952 in Tanzania
 Appeared in India in 1963Appeared in India in 1963
 Major epidemic outbreaks in Calcutta,Major epidemic outbreaks in Calcutta,
madras and other areasmadras and other areas
 Manifested with Major epidemics till 1973Manifested with Major epidemics till 1973

10. Clinical featuresClinical features
 Incubation 3 – 12 daysIncubation 3 – 12 days
 Fever may rise to 103Fever may rise to 10300
c to 104c to 10400
c withc with
rigorsrigors
 Viremia lead to fever.Viremia lead to fever.
Fever leads to release of large amount ofFever leads to release of large amount of
InterferonsInterferons

11. Clinical manifestationsClinical manifestations
 Fever,Fever,
 Crippling Joint painsCrippling Joint pains
 LymphadenopathyLymphadenopathy
 ConjunctivitisConjunctivitis
 A Maculopapular rashA Maculopapular rash
 May lead to hemorrhagic manifestations,May lead to hemorrhagic manifestations,
 Fever is biphasic with remission after 1 - 6 daysFever is biphasic with remission after 1 - 6 days
of fever.of fever.

12. How some Indian patientsHow some Indian patients
presentedpresented
 In India but not in Africa, patientsIn India but not in Africa, patients
presented with Inguinal lymphadenopathypresented with Inguinal lymphadenopathy
and red swollen ears, and are observedand red swollen ears, and are observed
as part of clinical picture.as part of clinical picture.

13. Morbidity and MortalityMorbidity and Mortality
 Fatalities are rare and when they occurFatalities are rare and when they occur
are associated with either with young ageare associated with either with young age
or with Thrombocytopeniaor with Thrombocytopenia
 Hemorrhagic version of illness, that canHemorrhagic version of illness, that can
lead to shocklead to shock

14. DiagnosisDiagnosis
 The primary differential diagnosis ofThe primary differential diagnosis of
Chikungunya, should be made fromChikungunya, should be made from
Dengue, and O’Nyong nyong feversDengue, and O’Nyong nyong fevers
 Chikungunya manifest with Myalgia ratherChikungunya manifest with Myalgia rather
than Arthritis.than Arthritis.

15. Microbiological DiagnosisMicrobiological Diagnosis
 Isolation of VirusIsolation of Virus
 Amplification of Nucleic acidAmplification of Nucleic acid
 Routine Diagnosis with serologyRoutine Diagnosis with serology
Detection of IgM antibodyDetection of IgM antibody
provides a specific and reliableprovides a specific and reliable
means for early diagnosismeans for early diagnosis
ELISA and Dot blotting methods are usedELISA and Dot blotting methods are used

16. TreatmentTreatment
 Chikungunya fever is not a life threateningChikungunya fever is not a life threatening
infection. Symptomatic treatment for mitigatinginfection. Symptomatic treatment for mitigating
pain and fever using anti-inflammatory drugspain and fever using anti-inflammatory drugs
along with rest usually suffices. While recoveryalong with rest usually suffices. While recovery
from Chikungunya is the expected outcome,from Chikungunya is the expected outcome,
convalescence can be prolonged (up to a yearconvalescence can be prolonged (up to a year
or more), and persistent joint pain may requireor more), and persistent joint pain may require
analgesic (pain medication) and long-term anti-analgesic (pain medication) and long-term anti-
inflammatory therapyinflammatory therapy

17. Vaccines for ChikungunyaVaccines for Chikungunya
 An experimental – live attenuated vaccineAn experimental – live attenuated vaccine
( TSI – GSD – 218 ) enveloped by( TSI – GSD – 218 ) enveloped by
passage of an isolate from Thailand inpassage of an isolate from Thailand in
MRC – 5 cell.MRC – 5 cell.
 At present used in some laboratoryAt present used in some laboratory
workers who can be protected,workers who can be protected,
Vaccine produces neutralizingVaccine produces neutralizing
antibodiesantibodies

18. How Chikungunya can beHow Chikungunya can be
PreventedPrevented
 There is neither Chikungunya virus vaccine nor drugsThere is neither Chikungunya virus vaccine nor drugs
are available to cure the infection. Prevention, therefore,are available to cure the infection. Prevention, therefore,
centers on avoiding mosquito bites. Eliminatingcenters on avoiding mosquito bites. Eliminating
mosquito breeding sites is another key preventionmosquito breeding sites is another key prevention
measure. To prevent mosquito bites, do the following:measure. To prevent mosquito bites, do the following:
 Use mosquito repellents on skin and clothingUse mosquito repellents on skin and clothing
 When indoors, stay in well-screened areas. Use bedWhen indoors, stay in well-screened areas. Use bed
nets if sleeping in areas that are not screened or air-nets if sleeping in areas that are not screened or air-
conditioned.conditioned.
 When working outdoors during day times, wear long-When working outdoors during day times, wear long-
sleeved shirts and long pants to avoid mosquito bite.sleeved shirts and long pants to avoid mosquito bite.

19. Control of breeding of AedesControl of breeding of Aedes
MosquitosMosquitos
Source reduction MethodSource reduction Method
(i) By elimination of all potential vector breeding(i) By elimination of all potential vector breeding
places near the domestic or peri-domestic areas.places near the domestic or peri-domestic areas.
(ii) Not allowing the storage of water for more than(ii) Not allowing the storage of water for more than
a week. This could be achieved by emptying and dryinga week. This could be achieved by emptying and drying
the water containers once in a week.the water containers once in a week.
(iii) Straining of the stored water by using a clean(iii) Straining of the stored water by using a clean
cloth once a week to remove the mosquito larvae fromcloth once a week to remove the mosquito larvae from
the water and the water can be reused. The sieved cloththe water and the water can be reused. The sieved cloth
should be dried in the sun to kill immature stages ofshould be dried in the sun to kill immature stages of
mosquitoes.mosquitoes.

20. Use of larvicidesUse of larvicides
(i) Where the water cannot be removed(i) Where the water cannot be removed
but used for cattle or other purposes, Temephosbut used for cattle or other purposes, Temephos
can be used once a week at a dose of 1 ppmcan be used once a week at a dose of 1 ppm
(parts per million).(parts per million).
(ii) Pyrethrum extract (0.1% ready-to-use(ii) Pyrethrum extract (0.1% ready-to-use
emulsion) can be sprayed in rooms (not outside)emulsion) can be sprayed in rooms (not outside)
to kill the adult mosquitoes hiding in the house.to kill the adult mosquitoes hiding in the house.

21. Indian EpidemicIndian Epidemic
 The states affected by chikungunya areThe states affected by chikungunya are
Andhra Pradesh, Karnataka, Maharasthra,Andhra Pradesh, Karnataka, Maharasthra,
Madhya Pradesh, Tamil Nadu, Gujarat &Madhya Pradesh, Tamil Nadu, Gujarat &
Kerala. In the year 2006, total number ofKerala. In the year 2006, total number of
1390322 suspected Chikungunya fever1390322 suspected Chikungunya fever
cases were reported from the country.cases were reported from the country.

22. Severity of IndianSeverity of Indian
EpidemicEpidemic
 Till 10 October 2006, 151 districts of eightTill 10 October 2006, 151 districts of eight
states/provinces of India have been affected bystates/provinces of India have been affected by
Chikungunya fever. The affected states areChikungunya fever. The affected states are
Andhra Pradesh, Andaman & Nicobar Islands,Andhra Pradesh, Andaman & Nicobar Islands,
Tamil Nadu, Karnataka, Maharashtra, Gujarat,Tamil Nadu, Karnataka, Maharashtra, Gujarat,
Madhya Pradesh, Kerala and Delhi.Madhya Pradesh, Kerala and Delhi.
 More than 1.25 million cases have beenMore than 1.25 million cases have been
reported from the country with 752,245 casesreported from the country with 752,245 cases
from Karnataka and 258,998 from Maharashtrafrom Karnataka and 258,998 from Maharashtra
provinces. In some areas attack rates haveprovinces. In some areas attack rates have
reached up to 45%.reached up to 45%.

23. Current Research onCurrent Research on
ChikungunyaChikungunya
 Researchers at the Institut Pasteur haveResearchers at the Institut Pasteur have
managed to retrace the origin and evolution ofmanaged to retrace the origin and evolution of
the Chikungunya virus in the Indian Oceanthe Chikungunya virus in the Indian Ocean
through complete sequencing of the genome ofthrough complete sequencing of the genome of
six viral strains isolated from patients fromsix viral strains isolated from patients from
Reunion Island and the Seychelles, as well asReunion Island and the Seychelles, as well as
through partial sequencing of the viral proteinthrough partial sequencing of the viral protein
E1 from 127 patients from the Indian OceanE1 from 127 patients from the Indian Ocean
islands (Reunion,Madagascar, Seychelles,islands (Reunion,Madagascar, Seychelles,
Mauritius, Mayotte). Their study, published inMauritius, Mayotte). Their study, published in
PLoS Medicine, opens up new research pathsPLoS Medicine, opens up new research paths
that should help to explain the magnitude of thethat should help to explain the magnitude of the
epidemic and the occurrence of severe forms ofepidemic and the occurrence of severe forms of
the disease.the disease.

24. Created for HealthCreated for Health
Awareness onAwareness on
ChikungunyaChikungunya
Dr.T.V.Rao MD.Dr.T.V.Rao MD.
EmailEmail
doctortvrao@gmail.comdoctortvrao@gmail.com