ARTHROPOD BORNE INFECTIOUS DISEASE: ARTHROPOD BORNE INFECTIOUS DISEASE
ARTHROPOD BORNE INFECTIOUS DISEASE: ARTHROPOD BORNE INFECTIOUS DISEASE MOSQUITO
TICK
BED-BUGS
LICE
SAND-FLY
BLACK-FLY
FLEA
ARTHROPOD BORNE INFECTIOUS DISEASE: ARTHROPOD BORNE INFECTIOUS DISEASE LOUSE-BORNE DISEASE
OVERCROWDING
POOR HYGIENE
POOR SHELTER
HUMANITARIAN EMERGENCIES
ARTHROPOD BORNE INFECTIOUS DISEASE: ARTHROPOD BORNE INFECTIOUS DISEASE SAND-FLY
LEISHMANIASIS
ARTHROPOD BORNE INFECTIOUS DISEASE: ARTHROPOD BORNE INFECTIOUS DISEASE FORMS OF INFECTION
CUTANEOUS INFECTION
KALA-AZAR
ARTHROPOD BORNE INFECTIOUS DISEASE: ARTHROPOD BORNE INFECTIOUS DISEASE BLACK-FLY
RIVER BLINDNESS
Onchocerca volvulus
ARTHROPOD BORNE INFECTIOUS DISEASE: ARTHROPOD BORNE INFECTIOUS DISEASE MOSQUITO
MALARIA
DENGUE
YELLOW FEVER
JAPANESE ENCEPHALITIS
YELLOW FEVER: YELLOW FEVER YELLOW FEVER VIRUS
TYPE STRAIN FOR FLAVIVIRIDAE
SUB SAHARAN AFRICA & SOUTH AMERICA
Aedes aegypti
WEST NILE VALLEY ENCEPHALITIS: WEST NILE VALLEY ENCEPHALITIS ORIGINALLY ISOLATED UGANDA 1937
MORE WIDESPREAD IN RECENT YEARS
FIRST REPORTED IN WESTERN HEMISPHERE
USA 1999
WEST NILE VALLEY ENCEPHALITIS: WEST NILE VALLEY ENCEPHALITIS NOW DISSEMINATED WIDELY IN US
ALSO REPORTED IN EUROPE
ENZOOTIC CYCLE BIRDS/MOSQUITOS
MOSQUITO - Culex pipiens MAINTAIN TRANSMISSION IN BIRDS
HUMAN INFECTION
HYBRIDS OF C. pipiens WITH OTHER SPECIES
Aedes aegypti : Aedes aegypti
DENGUE: DENGUE VIRUS
FAMILY: FLAVIVIRIDAE
GENUS: FLAVIVIRUS
(YELLOW FEVER/HEPATITIS C VIRUS)
40-50 NM SPHERICAL VIRUS
LIPID ENVELOPE
FLAVIVIRIDAE IN IRELAND: FLAVIVIRIDAE IN IRELAND
HEPATITIS C VIRUS
FLAVIVIRIDAE: FLAVIVIRIDAE GEMOME ABOUT 11 000 BASES
ENCODES
3 STRUCTURAL PROTEINS
7 NON-STRUCTURAL PROTEINS
FLAVIVIRIDAE: FLAVIVIRIDAE 3 MAJOR SUB-GROUPS
Flavivirus
Pestivirus (VETERINARY)
Hepacivirus
3 GROUPS SHARE COMMON GENOMIC STRUCTURE
DO NOT SHARE COMMON ANTIGENS
FLAVIVIRIDAE: FLAVIVIRIDAE 3 MAJOR SUB-GROUPS
Flavivirus
Pestivirus (VETERINARY)
Hepacivirus
DO NOT SHARE COMMON ANTIGENS
WHY IS THAT IMPORTANT?
DIAGNOSTIC TESTS BASED ON ANTIBODIES
FLAVIVIRIDAE: FLAVIVIRIDAE ROUTES OF TRANSMISSION
MOSQUITO BORNE
DENGUE
TICK BORNE
TICK BORNE ENCEPHALITIS(TBE)
NO KNOWN ARTHROPOD VECTOR
HEPATITIS C VIRUS
FLAVIVIRUS: FLAVIVIRUS FLAVIVIRUS HAVE COMMON GROUP EPITOPES ON THE ENVELOPE PROTEINS
WHY MIGHT THAT MATTER?
ANTIBODIES TO ONE MAY REACT TO SOME DEGREE WITH ANOTHER
IMPLICATIONS FOR
IMMUNITY
DIAGNSOTICS SEROLOGY
DENGUE –THE VIRUS: DENGUE –THE VIRUS FOUR SEROTYPES
DENV-1
DENV-2
DENV-3
DENV-4
DENGUE- THE VECTOR: DENGUE- THE VECTOR Aedes aegypti
SMALL MOSQUITO
URBAN/DOMESTICATED MOSQUITO
LAYS EGGS IN ARTIFICIAL CONTAINERS
VASES
CAR-TYRES
EMPTY PLASTIC BOTTLES
WATER STORAGE CONTAINERS (BARRELLS/CISTERNS)
DENGUE- THE VECTOR: DENGUE- THE VECTOR Aedes aegypti
ADULT MOSQUITO RESTS INDOORS
DAYLIGHT FEEDER
FEMALE IS A “NERVOUS FEEDER”
EASILY DISTURBED
MAY BITE/PROBE SEVERAL PEOPLE DURING ONE BLOOD MEAL
VIRUS MAY TRANSMIT DURING VERY BRIEF PROBE
WHOLE FAMILIES MAY DEVELOP INFECTION WITHIN 24/36 HOURS FROM ONE MOSQUITO
DENGUE INFECTION: DENGUE INFECTION VIRAL REPLICATION OVER 3 TO 14 DAYS
FOR 2- 3 DAYS IN LYMPH NODES THAT DRAIN THE REGION OF THE BITE
DISSEMINATE WITHIN 2 – 3 DAYS
INFECTS MONOCYTES, T CELLS & B CELLS
CONSEQUENCES OF DENGUE INFECTION: CONSEQUENCES OF DENGUE INFECTION
DEPENDS ON
THE VIRUS
STRAIN OF DENGUE VIRUS
1,2,3,& 4
BUT ALSO GENETIC DIVERSITY WITHIN EACH SEROTYPE
THE HOST
IMMUNE STATUS
AGE
GENETIC BACKGROUND
CONSEQUENCES OF DENGUE INFECTION: CONSEQUENCES OF DENGUE INFECTION
ASYMPTOMATIC/ MINIMALLY SYMPTOMATIC
ESPECIALLY YOUNGER CHILDREN
CONSEQUENCES OF DENGUE INFECTION: CONSEQUENCES OF DENGUE INFECTION DENGUE FEVER
(OLDER CHILDREN & ADULTS)
3 TO 14 DAYS INCUBATION PERIOD
SUDEN ONSET OF FEVER
FRONTAL HEADACE
BODY ACHES
NAUSEA/VOMITING
JOINT PAIN
RASH
ENLARGED LYMPH NODES
SKIN HAEMORRHAGES OR GUM & NOSE BLEEDING
USUALLY SELF-LIMIITNG
RARELY FATAL
CONSEQUENCES OF DENGUE INFECTION: CONSEQUENCES OF DENGUE INFECTION DENGUE HAEMORRHAGIC FEVER (DHF)
USUALLY IN CHILDREN < 15 YEARS
INITIAL ILLNESS VERY LIKE DENGUE FEVER
AROUND THE TIME THE FEVER RESOLVES
SEVERE HAEMORRHAGIC MANIFESTATIONS
SHOCK (CIRCULATORY COLLAPSE)
FLUID FROM BLOOD LEAKS INTO TISSUE FROM THE CAPILLARIES
CONSEQUENCES OF DENGUE INFECTION: CONSEQUENCES OF DENGUE INFECTION DENGUE HAEMORRHAGIC FEVER (DHF)
OUTCOME
IF SHOCK (CIRCULATORY COLLAPSE) IS PROFOUND AND NOT TREATED
RAPID DEATH
IF SHOCK IS LESS PROFOUND/EFFECTIVELY TREATED
RECOVERY MAY BE RAPID
CRITICAL ISSUE IN TREATMENT IS TO MAINTAIN VOLUME IN THE CIRCULATION BY INTRAVENOUS FLUIDS
WHAT CAUSES DHF: WHAT CAUSES DHF IMMUNE ENHANCEMENT HYPOTHESIS
PERSON PREVIOUSLY INFECTED WITH DENV1 HAS ANTIBODIES TO DENV-1
BECOMES INFECTED WITH DENV-3
ANTIBODIES TO DENV-1 BIND TO DENV-3
THE ANTI-DENV-1 ANTIBOIDES FAIL TO NEUTRALISE DENV-3
MACROPHAGES TAKE UP THE DENV-3 MORE EFFECTIVELY BECAUSE OF THE BOUND ANTIBODY
WHAT CAUSES DHF: WHAT CAUSES DHF IMMUNE ENHANCEMENT HYPOTHESIS
MORE INTENSE INFECTION OF MACROPHAGES/MONONUCLEAR CELLS
MORE PRODUCTION OF CYTOKINES/VASOACTIVE SUBSTANCES BY MACROPHAGES/MONONUCLEAR CELLS
GREATER DEGREE OF VASCULAR PERMEABILITY
WHAT CAUSES DHF: WHAT CAUSES DHF GENETIC VARIABILITY OF DENV HYPOTHESIS
MUTATIONS IN VIRAL GENOME RESULT IN DIVERSITY OF VIRUS
SOME MUTATIONS RESULT IN VIRUS WITH INCREASED ABILITY TO CAUSE SEVERE DISEASE
LABORATORY DIAGNOSIS OF DHF: LABORATORY DIAGNOSIS OF DHF HOW?
REMEMBER ONLY 2 THING
1. VIRUS/BITS OF VIRUS
2. HOST RESPONSE
LABORATORY DIAGNOSIS OF DHF: LABORATORY DIAGNOSIS OF DHF ANTIBODY DETECTION
ACUTE SAMPLE (WHEN ILLNESS STARTS)
CONVALESCENT SAMPLE (TAKEN AT/NEAR END OF ILLNESS)
IgM ELISA
BECOMES POSITIVE ABOUT DAY 5 OF ILLNESS
IgG DETECTION (HAEMAGGLUTINATION-INHIBITION)
WHAT DOES IgG MEAN?
LABORAOTRY DIAGNOSIS OF DHF: LABORAOTRY DIAGNOSIS OF DHF
ANTIBODY DETECTION
ACUTE SAMPLE (WHEN ILLNESS STARTS)
CONVALESCENT SAMPLE (TAKEN AT/NEAR END OF ILLNESS)
HIGHER LEVEL OF ATIBODY IN CONVALESCENT SAMPLE COMPARED WITH ACUTE SAMPLE
LABORAOTRY DIAGNOSIS OF DHF: LABORAOTRY DIAGNOSIS OF DHF VIRUS ISOLATION
TISSUE CULTURE
NUCLEIC ACID DETECTION
REVERSE TRANSCRIPTION & PCR
TREATMENT OF DENGUE VIRUS INFECTION: TREATMENT OF DENGUE VIRUS INFECTION
SUPPORTIVE
NO SPECIFIC ANTI-VIRAL TREATMENT
CONTROL OF DENGUE: CONTROL OF DENGUE VACCINE
NONE CURRENTLY AVAILABLE
BUT
3 LIVE ATTENUATED VACCINES UNDER DEVELOPMENT
ALSO
CHIMERIC VIRUS VACCINES
6 TETRAVALENT CANDIDATE VACCINES IN OR NEAR CLINICAL TRIALS
THE PEDIATRIC DENGUE VACCINE INITIATIVE
(BILL & MELINDA GATES FOUNDATION)
SPREAD OF DENGUE: SPREAD OF DENGUE 40% OF GLOBAL POPULATION AT RISK
ESTIMATED 50 MILLIION INFECTIONS PER YEAR
ENDEMIC IN > 100 COUNTRIES
GLOBAL DISTRIBUTION OF DENGUE: GLOBAL DISTRIBUTION OF DENGUE
SPREAD OF DENGUE: SPREAD OF DENGUE SPREAD IN RECENT DECADES
BEFORE 1971
ONLY 9 COUNTRIES HAD EXPERIENCED DHF EPIDEMICS
BY 1995
> 30 COUNTRIES HAD EXPERIENCED EPIDEMICS
SPREAD OF DENGUE: SPREAD OF DENGUE WHY THE SPREAD?
MAY BE MULTIPLE FACTORS
INCREASED AIR TRAVEL
INCREASED URBANISATION
INCREASED PLASTIC REFUSE
(WATER TRAP BREEDING SITES)
IS CLIMATE CHANGE A FACTOR?
CLIMATE CHANGE: CLIMATE CHANGE UN INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE
http://www.ipcc.ch/
WMO
WORLD METEOROLOGICAL ORGANIZATION
UNEP
UNITED NATIONS ENVIRONMENTAL PROGRAMME
ESTABLISHED IN 1988
CLIMATE CHANGE: CLIMATE CHANGE UN INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE (IPCC)
FIRST IPCC ASSESSMENT REPORT 1990
SECOND ASSESSMENT REPORT 1995
THIRD ASSESSMENT REPORT 2001
FOURTH ASSESSMENT REPORT 2007
CLIMATE CHANGE: CLIMATE CHANGE UN INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE (IPCC)
SUMMARY FOR POLICY MAKERS
CLIMATE CHANGE: CLIMATE CHANGE
ATMOSPHERIC CONCENTRATIONS OF CO2 METHANE AND NITROUS OXIDE FAR EXCEED PREINDUSTIAL LEVELS
CO2 FOSSIL FUEL USE & LAND USE CHANGE
METHANE & NITROUS OXIDE
AGRICULTURE
CLIMATE CHANGE: CLIMATE CHANGE CO2
280ppm PRE INDUSTRIAL
(RANGE OVER LAST 650 000 YEARS 180-300)
379 PPM 2005
FOSSIL FUEL USE & LAND USE CHANGE
METHANE
715ppb PRE INDUSTRIAL
(RANGE OVER LAST 650 000 YEARS 320-790)
1774 IN 2005
CLIMATE CHANGE: CLIMATE CHANGE “Warming of the climate system is unequivocal”
11 OF THE LAST 12 YEARS RANK AMONG THE 12 WARMEST YEARS SINCE RECORDS BEGAN IN 1850
CLIMATE CHANGE: CLIMATE CHANGE
SNOW COVER AND ICE EXTENT HAVE DIMINISHED
GLOBAL AVERAGE SEA LEVEL HAS INCREASED AT AN AVERAGE RATE OF 1.8 mm/YEAR FROM 1961-2003
FROM 1993-2003 RATE WAS 2.4 TO 3.8 mm/YEAR
SEA LEVEL HAS RISEN BY 0.17 M IN 20TH CENTURY
CLIMATE CHANGE: CLIMATE CHANGE
“MOST OF THE OBSERVED INCREASE IN GLOBALLY AVERAGED TEMPERATURES SINCE THE MID 20TH CENTURY IS VERY LIKELY DUE TO THE OBSERVED INCREASE IN ANTHROPOGENIC GREENHOUSE GAS CONCENTRATIONS.”
CLIMATE CHANGE: CLIMATE CHANGE IRELAND
ENVIRONMENTAL RTDI PROGRAMME 200-2006
CLIMATE CHANGE INDICATORS FOR IRELAND
CLIMATE CHANGE & HEALTH: CLIMATE CHANGE & HEALTH LICE
TYPHUS
RELAPSING FEVER
CLIMATE CHANGE & HEALTH: CLIMATE CHANGE & HEALTH
CLIMATE CHANGE & HEALTH: CLIMATE CHANGE & HEALTH LICE
TYPHUS
RELAPSING FEVER
CLIMATE CHANGE & HEALTH: CLIMATE CHANGE & HEALTH LICE
TYPHUS
RELAPSING FEVER
VECTOR BORNE DISEASE: VECTOR BORNE DISEASE LARGE BURDEN OF HUMAN DISEASE
HUMAN ACTIVITY IMPACTS ON
VECTOR NUMBERS
VECTOR DISTRIBUTION
SOCIAL STRUCTURE IMPACTS ON EXPOSURE TO VECTORS
OUTCOME OF INFECTION
VECTOR BORNE DISEASE: VECTOR BORNE DISEASE WHO
HUMAN INDUCED CLIMATE CHANGE MAY CAUSE 150 000 DEATHS/YEAR
MAINLY FROM
1. DIRECT:HEAT WAVES & DROUGHTS
2. INDIRECT: INFECTIOUS DISEASE
VECTOR BORNE DISEASE: VECTOR BORNE DISEASE CLIMATE & DENGUE
El Nino Southern Oscillation (ENSO)
REVERSAL OF CURRENTS IN PACIFIC
LINKED TO
DENGUE FEVER
DENGUE HAEMORRHAGIC FEVER
VECTOR BORNE DISEASE: VECTOR BORNE DISEASE CLIMATE CHANGE & MALARIA
CONFLICTING RESULTS
CLIMATE CHANE & CHOLERA
LINKS BETWEEN CHANGING PATTERNS OF RAINFALL AND INCREASED CHOLERA IN BANGLADESH
Koelle K. Nature 2005; 436:696-700
VECTOR BORNE DISEASE: VECTOR BORNE DISEASE CLIMATE CHANGE & MALARIA
CONFLICTING RESULTS
CLIMATE CHANE & CHOLERA
LINKS BETWEEN CHANGING PATTERNS OF RAINFALL AND INCREASED CHOLERA IN BANGLADESH
Koelle K. Nature 2005; 436:696-700
VECTOR BORNE DISEASE: VECTOR BORNE DISEASE
http://www.ehponline.org
CLIMATE CHANGE AND MOSQUITO BORNE DISEASE
Reiter P. 2001;109
“The natural history of mosquito-borne diseases is complex, and the interplay of climate, ecology, vector biology and many other factors defies simplistic analysis. The recent resurgence of many of these diseases is a major cause for concern, but it is facile to attribute this resurgence to climate change.”
READING: READING http://www.who.int/globalchange/en
GLOBAL ENVIRONMENTAL CHANGE
Dengue: an escalating problem. Gibbons RV, Vaughn DW
BMJ. 2002;324:1563-1566
http://www.who.int/mediacentre/factsheets/fs117/en/
http://www.scidev.net
CLIMATE CHANGE IN AFRICA