Chikungunya is an RNA virus transmitted by Aedes mosquitoes that causes fever and severe joint pain. It originated in Africa and parts of Asia and has caused several outbreaks. The document discusses the virus's history, symptoms, diagnosis, treatment and prevention methods such as mosquito control and repellents. No vaccine currently exists, so prevention focuses on avoiding mosquito bites.

1. CHIKUNGUNYA
AN UPDATE
Dr.T.V.Rao MD
DR.T.V.RAO MD 1

2. • Manifest with Crippling
Arthritic disease of sudden
onset.
• Name is derived from
Swahili – Chikungunya
meaning that which bends
up
• Virus isolated in 1953 from
serum and Aedes
mosquitoes and Culex spp
WHAT IS CHIKUNGUNYA
DR.T.V.RAO MD 2

3. 3
WHAT IS CHIKUNGUNYA?
• Chikungunya is a virus that is transmitted from human to
human mainly by infected Aedes albopictus and Aedes
aegypti mosquitoes (later referred to as Aedes
mosquitoes) acting as the disease-carrying vector
• Chikungunya causes sudden onset of high fever, severe
joint pain, muscle pain and headache
• As no vaccine or medication is currently available to
prevent or cure the infection, control of Chikungunya
involves vector control measures and encouraging people
to avoid mosquito bites
DR.T.V.RAO MD

4. EMERGING DISEASE
• Change in vector
distribution due to
global warming/
changing weather
patterns
• Endemicity to
epidemic
DR.T.V.RAO MD 4

5. • Isolated in Aedes aegypti
mosquitoes and man in
1952 in Tanzania
• Appeared in India in 1963
• Major epidemic outbreaks
in Calcutta, madras and
other areas
• Manifested with Major
epidemics till 1973
HISTORY
DR.T.V.RAO MD 5

6. CURRENT DISTRIBUTION OF
CHIKUNGUNYA
DR.T.V.RAO MD 6

7. 7
CHIKUNGUNYA RISK ZONES
Outbreaks of Chikungunya virus are usually found in:
• Africa
• Southeast Asia
• Indian subcontinent and islands in the Indian Ocean
DR.T.V.RAO MD

8. WHAT IS IMPORTANT IN CHIKUNGUNYA?
• Togaviridae alphavirus
• RNA virus able to
evolve rapidly and
expand vector
• Endemic in Africa and
Asia, especially India
• Vectored by Aedes
species (albopictus,
aegypti)
DR.T.V.RAO MD 8

9. • Family –
Togaviridae
• Genus - Alpha
virus
• Chikungunya viral
infection manifests
with febrile illness
CHIKUNGUNYA VIRUS
DR.T.V.RAO MD 9

10. CHIKUNGUNYA VIRUS
• Enveloped virions
spherical, 60 to 70
nm in diameter
positive-sense,
single-stranded RNA
genome, ca. 11.7
kilobases long.
DR.T.V.RAO MD 10

11. CHIKUNGUNYA VIRUS
• Two changes to the
structure of E1 Makes
the virus more likely
to enter mosquito
cells and replicate
after the insect has fed
on the blood of an
infected person.
DR.T.V.RAO MD 11

12. EPIDEMIOLOGICAL TRIAD
AGENT
HOST ENVIRONMENT
VECTOR
DR.T.V.RAO MD 12

13. EPIDEMICS OF CHIKUNGUNYA
Large epidemics were
recognized in Transvaal of
South Africa, Zambia, India
and South east Asia,
Philippines.
DR.T.V.RAO MD 13

14. • Out breaks occur during
rainy season with
increasing densities of
Aedes aegypti mosquito
• Mosquitos bites infect
the Humans
• Laboratory acquired
infection can also occur
OUT BREAKS OF CHIKUNGUNYA
DR.T.V.RAO MD 14

15. RECENT HISTORY
• 2005-2007 epidemic in
India 1.4 million
infected in 2006, 56K
infected 2007 Cases
continuing to be
reported every month
• Outbreak in Italy in
2007 OMG!
DR.T.V.RAO MD 15

16. NATURAL CYCLE
• Aedes mosquitoes
• Feed in daytime
• Breed in stagnant
water
• Small puddle
• Reservoir
• Primates
• Transient viremia 3-7
daysDR.T.V.RAO MD 16

17. CYCLE OF INFECTION
DR.T.V.RAO MD 17

18. OTHER VECTORS
• Both Ae. aegypti and Ae. albopictus have been implicated in
large outbreaks of Chikungunya. Whereas Ae. aegypti is
confined within the tropics and sub-tropics, Ae. albopictus
also occurs in temperate and even cold temperate regions. In
recent decades Ae. albopictus has spread from Asia to
become established in areas of Africa, Europe and the
Americas.
• In Africa several other mosquito vectors have been implicated
in disease transmission, including species of the A. furcifer-
taylori group and A. luteocephalus. There is evidence that
some animals, including non-primates, may act as reservoirs
DR.T.V.RAO MD 18

19. • Incubation 3 – 12 days
• Fever may rise to 1030c
to 1040c with rigors
• Viremia lead to fever.
Fever leads to release
of large amount of
Interferons
CLINICAL FEATURES
DR.T.V.RAO MD 19

20. CLINICAL EVENTS IN
CHIKUNGUNYA
DR.T.V.RAO MD 20

21. CLINICAL MANIFESTATIONS
• Fever,
• Crippling Joint pains
• Lymphadenopathy
• Conjunctivitis
• A Maculopapular rash
• May lead to hemorrhagic manifestations,
• Fever is biphasic with remission after 1 - 6 days
of fever.
DR.T.V.RAO MD 21

22. CLINICAL DISEASE
• Significant
morbidity, minimal
mortality
• Fever, rash, nausea,
fatigue, arthralgia
lasting days to
weeks
• Arthritis may be
long-term sequellae
DR.T.V.RAO MD 22

23. • In India but not in
Africa, patients
presented with
Inguinal
lymphadenopathy
and red swollen
ears, and are
observed as part of
clinical picture.
HOW SOME INDIAN PATIENTS
PRESENTED
DR.T.V.RAO MD 23

24. DIAGNOSIS OF CHIKUNGUNYA
( WHO )
• Several methods can be used for diagnosis. Serological tests,
such as enzyme-linked immunosorbent assays (ELISA), may
confirm the presence of IgM and IgG anti-Chikungunya
antibodies. IgM antibody levels are highest three to five weeks
after the onset of illness and persist for about two months. The
virus may be isolated from the blood during the first few days of
infection. Various reverse transcriptase–polymerase chain
reaction (RT–PCR) methods are available but are of variable
sensitivity. Some are suited to clinical diagnosis. RT–PCR
products from clinical samples may also be used for genotyping
of the virus, allowing comparisons with virus samples from
various geographical sources.
DR.T.V.RAO MD 24

25. • The primary differential
diagnosis of
Chikungunya, should
be made from Dengue,
and O’Nyong nyong
fevers
• Chikungunya manifest
with Myalgia rather
than Arthritis.
DIAGNOSIS
DR.T.V.RAO MD 25

26. LABORATORY CRITERIA
Laboratory criteria: at least one of the following
tests in the acute phase:
• Virus isolation
• Presence of viral RNA by RT-PCR
• Presence of virus specific IgM/IgG
antibodies in single serum sample
collected
• Seroconversion to virus-specific antibodies
in samples collected at least one to three
weeks apart
DR.T.V.RAO MD 26

27. MICROBIOLOGICAL DIAGNOSIS
• Isolation of Virus
• Amplification of Nucleic acid
• Routine Diagnosis with serology
Detection of IgM antibody provides a
specific and reliable means for early diagnosis
ELISA and Dot blotting methods are used
DR.T.V.RAO MD 27

28. TREATMENT
• Chikungunya fever is not a life threatening
infection. Symptomatic treatment for mitigating
pain and fever using anti-inflammatory drugs
along with rest usually suffices. While recovery
from Chikungunya is the expected outcome,
convalescence can be prolonged (up to a year or
more), and persistent joint pain may require
analgesic (pain medication) and long-term anti-
inflammatory therapy
DR.T.V.RAO MD 28

29. CDC GUIDELINES FOR MANAGEMENT OF
CHIKUNGUNYA
DR.T.V.RAO MD 29
• There is no vaccine or specific antiviral treatment
currently available for Chikungunya fever. Treatment is
symptomatic and can include rest, fluids, and
medicines to relieve symptoms of fever and aching
such as ibuprofen, naproxen, acetaminophen, or
paracetamol. Aspirin should be avoided. Infected
persons should be protected from further mosquito
exposure (staying indoors in areas with screens and/or
under a mosquito net) during the first few days of the
illness so they can not contribute to the transmission
cycle.

30. VACCINES FOR CHIKUNGUNYA
• An experimental – live attenuated vaccine
( TSI – GSD – 218 ) enveloped by passage
of an isolate from Thailand in MRC – 5 cell.
• At present used in some laboratory workers
who can be protected,
Vaccine produces neutralizing
antibodies
DR.T.V.RAO MD 30

31. 31
PREVENTIVE MEASURES
SEEKING PROTECTION FROM CHIKUNGUNYA
When staying in affected areas:
• Wear long-sleeved shirts and long trousers
• Use mosquito repellents, coils or other devices that will help
fend off mosquitoes
• If possible, sleep under bed nets pre-treated with insecticides
• If possible, set the air-conditioning to a low temperature at night
– mosquitoes do not like cold temperatures
• Pregnant women, children under 12 years old, and people with
immune disorders or severe chronic illnesses should be given
personalised advice
DR.T.V.RAO MD

32. HOW CHIKUNGUNYA CAN BE
PREVENTED
• There is neither Chikungunya virus vaccine nor drugs
are available to cure the infection. Prevention,
therefore, centres on avoiding mosquito
bites. Eliminating mosquito breeding sites is another
key prevention measure. To prevent mosquito bites,
do the following:
• Use mosquito repellents on skin and clothing
• When indoors, stay in well-screened areas. Use bed
nets if sleeping in areas that are not screened or air-
conditioned.
• When working outdoors during day times, wear long-
sleeved shirts and long pants to avoid mosquito bite.
DR.T.V.RAO MD 32

33. BREEDING PLACES OF AEDES MOSQUITOS
TRY TO ELIMINATE ….
DR.T.V.RAO MD 33

34. 34
REDUCING THE SPREAD OF THE
VECTOR
• The vector lives in a number of different habitats
• The presence of water is of great importance for
mosquitoes’ breeding as their eggs require water in order
to develop into adult mosquitoes
DR.T.V.RAO MD

35. USE OF LARVICIDES
(i) Where the water cannot be removed but
used for cattle or other purposes, Temephos
can be used once a week at a dose of 1 ppm
(parts per million).
(ii) Pyrethrum extract (0.1% ready-to-use
emulsion) can be sprayed in rooms (not
outside) to kill the adult mosquitoes hiding in
the house.
DR.T.V.RAO MD 35

36. SEVERITY OF INDIAN EPIDEMIC
• Till 10 October 2006, 151 districts of eight
states/provinces of India have been affected by
Chikungunya fever. The affected states are Andhra
Pradesh, Andaman & Nicobar Islands, Tamil Nadu,
Karnataka, Maharashtra, Gujarat, Madhya Pradesh,
Kerala and Delhi.
• More than 1.25 million cases have been reported from the
country with 752,245 cases from Karnataka and 258,998
from Maharashtra provinces. In some areas attack rates
have reached up to 45%.
DR.T.V.RAO MD 36

37. CURRENT RESEARCH ON
CHIKUNGUNYA
• Researchers at the Institute Pasteur have managed to
retrace the origin and evolution of the Chikungunya
virus in the Indian Ocean through complete
sequencing of the genome of six viral strains isolated
from patients from Reunion Island and the
Seychelles, as well as through partial sequencing of
the viral protein E1 from 127 patients from the Indian
Ocean islands (Reunion, Madagascar, Seychelles,
Mauritius, Mayotte). Their study, published in PLoS
Medicine, opens up new research paths that should
help to explain the magnitude of the epidemic and the
occurrence of severe forms of the disease.
DR.T.V.RAO MD 37

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39. • Created by Dr.T.V.Rao MD for ‘e’
learning resources for Medical and
Public Health Personal in the
Developing World
• Email
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DR.T.V.RAO MD 39