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Chikungunya an update

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Chikungunya an update

Chikungunya an update

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Chikungunya an update Chikungunya an update Presentation Transcript

  • CHIKUNGUNYA AN UPDATE Dr.T.V.Rao MDDR.T.V.RAO MD 1
  • WHAT IS CHIKUNGUNYA• 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 sppDR.T.V.RAO MD 2
  • 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 3
  • EMERGING DISEASE• Change in vector distribution due to global warming/ changing weather patterns• Endemicity to epidemic DR.T.V.RAO MD 4
  • HISTORY• 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 1973DR.T.V.RAO MD 5
  • CURRENT DISTRIBUTION OF CHIKUNGUNYADR.T.V.RAO MD 6
  • CHIKUNGUNYA RISK ZONESOutbreaks of Chikungunya virus are usually found in: • Africa • Southeast Asia • Indian subcontinent and islands in the Indian Ocean DR.T.V.RAO MD 7
  • 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
  • CHIKUNGUNYA VIRUS• Family – Togaviridae• Genus - Alpha virus• Chikungunya viral infection manifests with febrile illnessDR.T.V.RAO MD 9
  • 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
  • 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
  • EPIDEMIOLOGICAL TRIAD AGENT VECTOR HOST ENVIRONMENTDR.T.V.RAO MD 12
  • 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
  • OUT BREAKS OF CHIKUNGUNYA• Out breaks occur during rainy season with increasing densities of Aedes aegypti mosquito• Mosquitos bites infect the Humans• Laboratory acquired infection can also occurDR.T.V.RAO MD 14
  • 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
  • NATURAL CYCLE • Aedes mosquitoes • Feed in daytime • Breed in stagnant water • Small puddle • Reservoir • Primates • Transient viremia 3-7 DR.T.V.RAO MD days 16
  • CYCLE OF INFECTIONDR.T.V.RAO MD 17
  • 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 reservoirsDR.T.V.RAO MD 18
  • CLINICAL FEATURES• 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 InterferonsDR.T.V.RAO MD 19
  • CLINICAL EVENTS IN CHIKUNGUNYADR.T.V.RAO MD 20
  • 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
  • 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
  • HOW SOME INDIAN PATIENTS PRESENTED• In India but not in Africa, patients presented with Inguinal lymphadenopathy and red swollen ears, and are observed as part of clinical picture.DR.T.V.RAO MD 23
  • 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
  • DIAGNOSIS• The primary differential diagnosis of Chikungunya, should be made from Dengue, and O’Nyong nyong fevers• Chikungunya manifest with Myalgia rather than Arthritis.DR.T.V.RAO MD 25
  • LABORATORY CRITERIALaboratory criteria: at least one of the followingtests 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 apartDR.T.V.RAO MD 26
  • 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
  • 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 therapyDR.T.V.RAO MD 28
  • CDC GUIDELINES FOR MANAGEMENT OF CHIKUNGUNYA• 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.DR.T.V.RAO MD 29
  • 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 antibodiesDR.T.V.RAO MD 30
  • PREVENTIVE MEASURES SEEKING PROTECTION FROM CHIKUNGUNYAWhen 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 31
  • 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
  • BREEDING PLACES OF AEDES MOSQUITOS TRY TO ELIMINATE ….DR.T.V.RAO MD 33
  • 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 34
  • 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
  • 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
  • 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
  • FOLLOW ME FOR MORE ARTICLES OF INTEREST ON INFECTIOUS DISEASESDR.T.V.RAO MD 38
  • • Created by Dr.T.V.Rao MD for ‘e’ learning resources for Medical and Public Health Personal in the Developing World • Email • doctortvrao@gmail.comDR.T.V.RAO MD 39