EPIDEMIOLOGY OF EPIDEMIOLOGY OF CHIKUNGUNYACHIKUNGUNYA

Definition:Definition:The study of the distribution and the The study of the distribution and the determinants of health related states or determinants of health related states or events in specified population and the events in specified population and the application of this study to the control of application of this study to the control of health problemshealth problems

EPIDEMIOLOGICAL PYRAMIDEPIDEMIOLOGICAL PYRAMID► It includes It includes

host

environment

Agent

VECTOR AND MODE OF VECTOR AND MODE OF TRANSMISSIONTRANSMISSION

► It’s a vector borne diseaseIt’s a vector borne disease►Vector is mosquito belonging to Vector is mosquito belonging to

“AEDES” genus“AEDES” genus►Other diseases caused by Aedes are Other diseases caused by Aedes are ► DENGUE HAEMORRHAGIC FEVERDENGUE HAEMORRHAGIC FEVER► YELLOW FEVERYELLOW FEVER►RIFT VALLEY FEVERRIFT VALLEY FEVER

DESCRIPTION ABOUT AEDESDESCRIPTION ABOUT AEDES

► Important members causing Important members causing chickungunya are chickungunya are

►Aedes aegyptiAedes aegypti►Aedes albopictusAedes albopictus►Aedes africanusAedes africanus►Aedes furciferAedes furcifer►Aedes tayloriAedes taylori►Aedes cordelliriAedes cordelliri

Aedes aegyptiAedes aegypti

Aedes mosquitoAedes mosquito

►Abundantly seen in indiaAbundantly seen in india►Called “TIGER MOSQUITO” (white Called “TIGER MOSQUITO” (white

stripes on the black body)stripes on the black body)►Favourable climate tropical 27*cFavourable climate tropical 27*c►Life span of adult mosquito -15 daysLife span of adult mosquito -15 days►Habitat –mainly indoor-living Habitat –mainly indoor-living

room,offices, bussiness places, in room,offices, bussiness places, in isolated containersisolated containers

Breeding habitsBreeding habitsArtificial accumulation of water Artificial accumulation of water

in:in:► Broken bottlesBroken bottles►Discarded tinsDiscarded tins► Fire bracketsFire brackets► Flower potsFlower pots► Coconut shellsCoconut shells► Earthen potsEarthen pots► Tree holesTree holes► Rubber containersRubber containers► Plastic containersPlastic containers

Breeding places of mosquitoBreeding places of mosquito

Biting habitsBiting habits

►Only the female mosquito bitesOnly the female mosquito bites►Bites mainly in day timeBites mainly in day time►Bites humans and animalBites humans and animal►Powerful bites / fearless bitesPowerful bites / fearless bites►Bites 3 to 4 times for a satisfactory Bites 3 to 4 times for a satisfactory

meal meal

Resting habits Flying habits Resting habits Flying habits

► Rests in dark Rests in dark corners, walls, corners, walls, umbrellas, book umbrellas, book shelves, coolers, shelves, coolers, bed covers.bed covers.

► Flies around 100 Flies around 100 mts from breeding mts from breeding placesplaces

► This factor helps in This factor helps in its eradicationits eradication

► Transported to long Transported to long distances by aero distances by aero planes , ship, train.planes , ship, train.

Life cycleLife cycle

MODE OF TRANSMISSIONMODE OF TRANSMISSION►Only the female Aedes bites(blood meal)Only the female Aedes bites(blood meal)►Transmission cycle:Transmission cycle:

ManMan

►Becomes infective after ten days of bite Becomes infective after ten days of bite & remains life long infective& remains life long infective

MosquitMosquitoo

In Africa In Africa

►Viruses transmitted in Savanna & Viruses transmitted in Savanna & forests of Africa by Aedes forests of Africa by Aedes africanus,Aedes furcifer africanus,Aedes furcifer

►Vertebrate portion of the cycle is Vertebrate portion of the cycle is provided by non human primates like provided by non human primates like monkeys & Baboons which amplify monkeys & Baboons which amplify and maintain virus circulationand maintain virus circulation

In Asia In Asia

►Virus is primarily transmitted by Aedes Virus is primarily transmitted by Aedes aegypti and to a lesser extent by aegypti and to a lesser extent by Aedes albopictus in urban areas.Aedes albopictus in urban areas.

►Although Asian monkeys develop Although Asian monkeys develop significant viraemia after inoculation. significant viraemia after inoculation. But they But they never never have been shown to have been shown to participate in maintenance or participate in maintenance or amplification of the virusamplification of the virus

GLOBAL OUTBREAKGLOBAL OUTBREAKYearYear PlacePlace No.of CasesNo.of Cases

19521952 TANZANIATANZANIA

(IN AFRICA)(IN AFRICA)__

1958-19621958-1962 BANGKOK & BANGKOK & THAILANDTHAILAND

__

2005 2005 DEC- APRIL DEC- APRIL 0606

REUNION REUNION ISLANDISLAND

2,25,0002,25,000

99THTH JAN – 10 JAN – 10THTH MARCH 06MARCH 06

MAYOTTEMAYOTTE 28332833

WHOWHO

INDIAN OUTBREAKINDIAN OUTBREAKYEAR YEAR PLACEPLACE NO.OF NO.OF

CASESCASESSOURCESOURCE

19631963 CALCUTTACALCUTTA Lakhs Lakhs

200 death200 deathICMR ICMR

Bulletin Bulletin May1980May1980

19641964 MADRASMADRAS lakhslakhs IJMR 1964IJMR 1964

19731973 MAHARASMAHARASHTRAHTRA

Small Small outbreaksoutbreaks

--

2005 Dec2005 Dec APAP 2,00,0002,00,000 Wikipedia Wikipedia May5th-06May5th-06

2005 Dec2005 Dec KarnatakKarnatakaa

78,00078,000 Wikipedia Wikipedia May5th-06May5th-06

Present epidemic in south Present epidemic in south IndiaIndia

►Mainly affected states areMainly affected states are► Karnataka , Maharashtra, APKarnataka , Maharashtra, AP► Recent update on JULY 5Recent update on JULY 5thth 2006 2006

DISTRICTDISTRICT NO. OF CASESNO. OF CASES

GULBARGAGULBARGA 5500055000

BIDARBIDAR 4200042000

TUMKURTUMKUR 3300033000

CHITRADURGACHITRADURGA 2000020000

BANGALORE RURALBANGALORE RURAL 80008000

BANGALORE URBANBANGALORE URBAN 20002000 *wikipedia pandemic chikungunya