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Dengue in pakistan

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Dengue

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Dengue in pakistan

  1. 1. Update on Outbreak PathogenesisUpdate on Outbreak Pathogenesis Diagnosis and other aspects of ViralDiagnosis and other aspects of Viral Haemorrhagic Fever in Pakistan 8Haemorrhagic Fever in Pakistan 8thth November 2006November 2006 Dr. Abbas HayatDr. Abbas Hayat Head Department of PathologyHead Department of Pathology Rawalpindi Medical College.Rawalpindi Medical College.
  2. 2. Aedes aegyptiAedes aegypti MosquitoMosquito
  3. 3. Historical BackgroundHistorical Background The earliest reports of a dengue-likeThe earliest reports of a dengue-like disease are from Chin Dynasty Chinadisease are from Chin Dynasty China (265-420 AD). The first rigorously(265-420 AD). The first rigorously documented outbreaks occurred almostdocumented outbreaks occurred almost simultaneously in:simultaneously in: Cairo and Alexandria (Egypt, 1799);Cairo and Alexandria (Egypt, 1799); Jakarta (the called Batavia, Indonesia,Jakarta (the called Batavia, Indonesia, 1799);1799); Philadelphia (United States, 1780);Philadelphia (United States, 1780); Madras (India, 1780).Madras (India, 1780).
  4. 4. The virus identified in 1940's : it becameThe virus identified in 1940's : it became a concern to armies fighting in Pacific anda concern to armies fighting in Pacific and Asia as it was causing a large number ofAsia as it was causing a large number of non-combat casualties to Allied andnon-combat casualties to Allied and Japanese forces.Japanese forces. Japanese scientists first identified theJapanese scientists first identified the virus in 1943 and were quickly followed byvirus in 1943 and were quickly followed by U.S. researchers. By 1956 the fourU.S. researchers. By 1956 the four serotypes of the virus identified and everyserotypes of the virus identified and every outbreak of the disease since has beenoutbreak of the disease since has been due to a virus belonging to one of the fourdue to a virus belonging to one of the four serotypes.serotypes.
  5. 5. Case fatality Rate of DF/DHF in SE AsiaCase fatality Rate of DF/DHF in SE Asia Karachi 2005
  6. 6. BackgroundBackground Sporadic cases of VHF in late SeptSporadic cases of VHF in late Sept and early Octand early Oct Media report of VHF in early Nov 2005Media report of VHF in early Nov 2005 – 2 HCWs died2 HCWs died – Laboratory results negative for CCHFLaboratory results negative for CCHF AKU reports increased number ofAKU reports increased number of VHFVHF – Clinical presentation and laboratoryClinical presentation and laboratory results consistent with Dengueresults consistent with Dengue Hemorrhagic feverHemorrhagic fever
  7. 7. YearYear LocationLocation No ofNo of cases/Deathscases/Deaths Positive by LabPositive by Lab 20032003 HaripurHaripur 1000 (7 deaths)1000 (7 deaths) 7 out of 117 out of 11 (Den Type-2)(Den Type-2) 20032003 KhushabKhushab (Nowshera)(Nowshera) 2500 (112500 (11 deaths)deaths) 7 out of 177 out of 17 (Den Type-2)(Den Type-2) 19951995 Hubb,Hubb, (Balochistan)(Balochistan) -------- 57 out 7657 out 76 Den antibodiesDen antibodies JuneJune 1994 to1994 to Sept 95Sept 95 KarachiKarachi 145 (01 death)145 (01 death) MultipleMultiple serotypes ofserotypes of DengueDengue Reported Dengue Epidemics in Pakistan
  8. 8. Preliminary FindingsPreliminary Findings of Karachi Outbreakof Karachi Outbreak (29(29thth Sept – 2Sept – 2ndnd DecDec 2005)2005)  106 VHF patients admitted to three106 VHF patients admitted to three tertiary care hospitalstertiary care hospitals >34% cases confirmed by>34% cases confirmed by serologyserology  Mean age 29 yrs (Range 3-78yrs)Mean age 29 yrs (Range 3-78yrs)
  9. 9. 2% 28% 26% 23% 21% < 10 y 10 to 19 20-29 30-39 > 39 Age Distribution of Patients with DHFAge Distribution of Patients with DHF Review of Records at AKU, CHK, JPMC
  10. 10. 25% 75% Female Male Gender Distribution of Patients with DHFGender Distribution of Patients with DHF Review of Records at AKU, CHK, JPMC
  11. 11. Outcome of Patients with DHF (Outcome of Patients with DHF (nn=106)=106) Review of Records at AKU, CHK, JPMC 8% 41% 30% 7% 14% Deaths Discharge Inpatients Other Unk
  12. 12. Update on September - November 2006 Outbreak in Pakistan  Teaching Hospitals of RMC reporting large numbers of patients seen in OPD setting with unexplained fever  Suspect many cases are being seen and managed at primary care level
  13. 13. PAKISTAN: Eid travel bringsPAKISTAN: Eid travel brings dengue fever Northdengue fever North 24 Oct 200624 Oct 2006 (( media headlinesmedia headlines)) The Pathology department atThe Pathology department at Rawalpindi Medical College, close toRawalpindi Medical College, close to the capital, Islamabad, expressedthe capital, Islamabad, expressed apprehension that "as more and moreapprehension that "as more and more people arrive from areas in Sindhpeople arrive from areas in Sindh where the disease is endemic, there iswhere the disease is endemic, there is a danger the epidemic will spread".a danger the epidemic will spread".
  14. 14. Mosquitoes spreading the disease have ended up in buses trains and airplanes heading north; or those already infected with the virus in the south have been bitten by local mosquitoes at their destination, causing the disease to spread further.
  15. 15. Till yesterday 8Till yesterday 8thth November 2006November 2006 Reported Suspected cases in PakistanReported Suspected cases in Pakistan 32303230 ConfirmedConfirmed 11131113 Total Cases in the Twin Cities 500Total Cases in the Twin Cities 500 ConfirmedConfirmed 175175 Total deathsTotal deaths 3333 Cases being reported from Khushab ChakwalCases being reported from Khushab Chakwal Pindi gheb Nowshera Peshawar Lahore etc.Pindi gheb Nowshera Peshawar Lahore etc. ( media reports)( media reports)
  16. 16. Disease PathogenesisDisease Pathogenesis
  17. 17. Replication and TransmissionReplication and Transmission of Dengue Virus (Part 1)of Dengue Virus (Part 1) 1. Virus transmitted to human in mosquito saliva 2. Virus replicates in target organs 3. Virus infects white blood cells and lymphatic tissues 4. Virus released and circulates in blood 3 4 1 2
  18. 18. Transmission of Dengue VirusTransmission of Dengue Virus byby Aedes aegyptiAedes aegypti Viremia Viremia Extrinsic incubation period DAYS 0 5 8 12 16 20 24 28 Human #1 Human #2 Illness Mosquito feeds / acquires virus Mosquito refeeds / transmits virus Intrinsic incubation period Illness
  19. 19. Neutralizing antibody to Dengue 1 virus 1 1 Dengue 1 virus1 Homologous Antibodies FormHomologous Antibodies Form Non-infectious ComplexesNon-infectious Complexes Non-neutralizing antibody 1 1 Complex formed by neutralizing antibody and virus
  20. 20. Replication and TransmissionReplication and Transmission of Dengue Virus (Part 2)of Dengue Virus (Part 2) 5. Second mosquito ingests virus with blood 6. Virus replicates in mosquito midgut and other organs, infects salivary glands 7. Virus replicates in salivary glands 6 7 5
  21. 21. Risk Factors for DHFRisk Factors for DHF (continued)(continued) Higher risk in secondaryHigher risk in secondary infectionsinfections Higher risk in locations withHigher risk in locations with two or more serotypestwo or more serotypes circulating simultaneously atcirculating simultaneously at high levels (hyperendemichigh levels (hyperendemic transmission)transmission)
  22. 22. Hypothesis on PathogenesisHypothesis on Pathogenesis of DHF (Part 1)of DHF (Part 1) Persons who have experienced aPersons who have experienced a dengue infection develop serumdengue infection develop serum antibodies that can neutralize theantibodies that can neutralize the dengue virus of that samedengue virus of that same ((homologoushomologous) serotype) serotype
  23. 23. Increased Probability of DHFIncreased Probability of DHF Hyperendemicity Increased circulation of viruses Increased probability of secondary infection Increased probability of occurrence of virulent strains Increased probability of immune enhancement Increased probability of DHF Gubler & Trent, 1994
  24. 24. Hypothesis on PathogenesisHypothesis on Pathogenesis of DHF (Part 2)of DHF (Part 2) In a subsequent infection, the pre-In a subsequent infection, the pre- existingexisting heterologousheterologous antibodiesantibodies form complexes with the newform complexes with the new infecting virus serotype, but do notinfecting virus serotype, but do not neutralize the new virusneutralize the new virus
  25. 25. Non-neutralizing antibody to Dengue 1 virus Dengue 2 virus 2 2 2 2 2 Heterologous AntibodiesHeterologous Antibodies Form InfectiousForm Infectious ComplexesComplexes Complex formed by non-neutralizing antibody and virus 2
  26. 26. 2 2 2 2 2 22 2 2 2 Heterologous Complexes EnterHeterologous Complexes Enter More Monocytes, Where VirusMore Monocytes, Where Virus ReplicatesReplicates Non-neutralizing antibody Dengue 2 virus2 Complex formed by non- neutralizing antibody and Dengue 2 virus 2
  27. 27. Hypothesis on PathogenesisHypothesis on Pathogenesis of DHF (Part 3)of DHF (Part 3) Antibody-dependent enhancementAntibody-dependent enhancement is the process in which certainis the process in which certain strains of dengue virus, complexedstrains of dengue virus, complexed with non-neutralizing antibodies,with non-neutralizing antibodies, can enter a greater proportion ofcan enter a greater proportion of cells of the mononuclear lineage,cells of the mononuclear lineage, thus increasing virus productionthus increasing virus production
  28. 28. DiagnosisDiagnosis
  29. 29. Key Lab. Diagnostic TestsKey Lab. Diagnostic Tests.. Virus isolation by infection of new-bornVirus isolation by infection of new-born mice with blood or infected mosquitoesmice with blood or infected mosquitoes PCRPCR Detection of antigens or antibody to theDetection of antigens or antibody to the agent in the blood (serology)agent in the blood (serology) ELISA is availableELISA is available ThrombopeniaThrombopenia Raised hematocritRaised hematocrit Decreased platelets and increase ALTDecreased platelets and increase ALT
  30. 30. Clinical laboratory testsClinical laboratory tests – CBC--WBC, platelets, hematocritCBC--WBC, platelets, hematocrit – AlbuminAlbumin – Liver function testsLiver function tests – Urine--check for microscopicUrine--check for microscopic hematuriahematuria Dengue-specific testsDengue-specific tests – Virus isolationVirus isolation – SerologySerology
  31. 31. Virus Isolation:Virus Isolation: Cell CultureCell Culture
  32. 32. Recommendations for PreventionRecommendations for Prevention and Controland Control  Environmental assessment and vector controlEnvironmental assessment and vector control – Vector surveillance and responseVector surveillance and response Chemical, biologic methods, and personal protective measuresChemical, biologic methods, and personal protective measures – Integrated management with community level involvementIntegrated management with community level involvement – Health education at the communityHealth education at the community  Emergency preparednessEmergency preparedness – Hospital level plans to manage patientsHospital level plans to manage patients  Capacity development and trainingCapacity development and training – Vector controlVector control – SurveillanceSurveillance – Clinical managementClinical management – Infection controlInfection control
  33. 33. In the battle against spread of Dengue virusIn the battle against spread of Dengue virus biggest barrier seems is misinformation as well asbiggest barrier seems is misinformation as well as ignorance,ignorance, ““The claim of National Institute of Health,The claim of National Institute of Health, Islamabad, that not all labs can carry out theIslamabad, that not all labs can carry out the diagnostic tests for Dengue is totally false and thediagnostic tests for Dengue is totally false and the kit does not need the Bio-safety-level-3 protocol.”kit does not need the Bio-safety-level-3 protocol.” Owing to confusion created by medical circles,Owing to confusion created by medical circles, several private labs are charging thousands ofseveral private labs are charging thousands of rupees for these tests, while they hardly costrupees for these tests, while they hardly cost around Rs500-800 at the mainstream diagnosticaround Rs500-800 at the mainstream diagnostic centers. Private hospital labs are said to becenters. Private hospital labs are said to be charging around Rs3,000 for the same tests.charging around Rs3,000 for the same tests.
  34. 34. At many hospitals, patients are being keptAt many hospitals, patients are being kept in isolation wards with the staff treatingin isolation wards with the staff treating hem wearing masks and gloves which ishem wearing masks and gloves which is also unnecessary.also unnecessary. Generally GPs in the city start treating feverGenerally GPs in the city start treating fever with anti-malarial or anti-biotic medicines,with anti-malarial or anti-biotic medicines, while in an epidemic situation, allwhile in an epidemic situation, all treatments should be followed by pre-treatments should be followed by pre- testing to rule out the possibility oftesting to rule out the possibility of contracting the disease that is spreading.contracting the disease that is spreading. But this is usually not done and in someBut this is usually not done and in some cases this negligence proves fatal.cases this negligence proves fatal.
  35. 35. At the same time, the anti-biotics and anti-malarialAt the same time, the anti-biotics and anti-malarial drugs bear a serious toxic effect on bone marrow.drugs bear a serious toxic effect on bone marrow. This impairs the production of white blood cellsThis impairs the production of white blood cells (WBCs) and platelets.(WBCs) and platelets. What is interesting is that the Dengue virus alsoWhat is interesting is that the Dengue virus also acts in the same manner by killing WBCs andacts in the same manner by killing WBCs and platelets. The combination of the two greatlyplatelets. The combination of the two greatly worsens the condition.worsens the condition. Dengue mosquito has certain peculiarDengue mosquito has certain peculiar characteristics, which have serious implicationscharacteristics, which have serious implications on Dengue Hemorrhagic Fever (DHF) control.on Dengue Hemorrhagic Fever (DHF) control.
  36. 36. A patched body which slightly differentA patched body which slightly different from malarial mosquito, secondly, itfrom malarial mosquito, secondly, it can transmit the disease with every bitecan transmit the disease with every bite unlike the other which undergoes a 15-unlike the other which undergoes a 15- day cycle of maturing before making itsday cycle of maturing before making its bite lethal again.bite lethal again. Worrisome is that the Aedes aegyptiWorrisome is that the Aedes aegypti mosquito is a dawn-and-dusk-bitermosquito is a dawn-and-dusk-biter when it is difficult to sense the bite.when it is difficult to sense the bite. While window screening and bedWhile window screening and bed netting may help until dawn, but mostlynetting may help until dawn, but mostly people are outdoors at duskpeople are outdoors at dusk
  37. 37. Another problem : since it tends toAnother problem : since it tends to breed inside closets, and in waterbreed inside closets, and in water containers that are cool andcontainers that are cool and covered, they are likely to findcovered, they are likely to find opportune breeding ground insideopportune breeding ground inside water storage tanks of houses aswater storage tanks of houses as well as in institutions like prisons,well as in institutions like prisons, hostels, hospitals, and schools.hostels, hospitals, and schools. That is why clustering of cases isThat is why clustering of cases is witnessed and it spreads like wildwitnessed and it spreads like wild fire.fire.
  38. 38. ““It is wise to cover the body properly withIt is wise to cover the body properly with clothing and apply mosquito repellantsclothing and apply mosquito repellants adequately on the exposed skin surface. Anadequately on the exposed skin surface. An ingredient in the repellants DEET actuallyingredient in the repellants DEET actually works to keep these biters away becauseworks to keep these biters away because with its peculiar odor.with its peculiar odor. Mustard oil for its strong smell also servesMustard oil for its strong smell also serves the same purpose,”the same purpose,” The myths surrounding the reality of thisThe myths surrounding the reality of this disease are making it all the more difficult todisease are making it all the more difficult to deal with it, contend medical practitioners.deal with it, contend medical practitioners. “Internationally, the mortality rate of DHF is“Internationally, the mortality rate of DHF is hardly 2% while our data shows anhardly 2% while our data shows an alarmingly high 5-10% only because ofalarmingly high 5-10% only because of improper disease management,”improper disease management,”
  39. 39. Thank youThank you

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