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Dengue and chikungunya f

The document discusses Dengue fever (DF), a mosquito-borne viral disease. It provides details on the history, transmission, clinical presentation, diagnosis and treatment of DF. DF is common in tropical and sub-tropical regions and is caused by the dengue virus, which has four serotypes. While most cases are mild, infection with a second serotype increases the risk of severe dengue which can be fatal if not properly treated through fluid resuscitation. Prevention relies on controlling the mosquito vectors and avoiding mosquito bites. There is no vaccine available for all four serotypes.

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পৃথিবীর সবচাইতে সুন্দর গাছ. জাপাতেI ওতেতেথরো:বযাপক আকাতরর । সারা পৃথিবী থিতক অসংখ্য মােুষ এই গাছ থেখ্তে আতস। ১৯৯০ বগগ ফু ট
DENGUE FEVER Dr mohammad nurul huq
History of DF • 1780: epidemics in in Asia, Africa, N America • First in Bangladesh in 1964 (Dacca Fever) • 1968: a small outbreak occurred in border with Myanmar • In India DF was first recorded in 1812. A double peak hemorrhagic F epidemic occurred in Calcutta 1963-64 • In N Delhi, outbreaks reported in 1967, 1970, 1982, 1996
Overview of Dengue Fever The commonest mosquito-borne viral disease • Aka ‘break bone fever’, Dandy fever • A multisystem inf. with wide clinical spectrum: ILI to fatal • Found in tropical & sub-tropical, mostly in urban & semi-urban areas • Risks: rainfall, temp., unplanned rapid urbanization • Severe DF is a leading c/of serious illness & death among children in some Asian & LatAm countries Aka: also known as. ILI: influenza like illness 7 Probably from Spanish, probably of African origin; compare Swahili kidinga
• Despite its complex features, Rx is relatively simple, cheap & very effective if timely done. Maintenance of body fluid is critical in severe DF • The success key is early Dx & knowing its different phases • Rx at the primary & secondary levels are critical. A well- managed front-line response reduces admissions • No specific Rx. • Fatality <1% • Prevention & control depends on effective vector control measures
• Vectors: mainly female A aegypti, less: A albopictus • 4 closely related serotypes: DENV-1, -2, -3, -4 • Every serotype can cause severe & fatal disease • Recovery from 1 gives lifelong immunity against that. Cross-immunity to another serotypes is partial & temporary: subsequent inf. by that increases the risk of severe DF • 500,000 DHF are admitted/y: a large portion are children • Death: 10,000/y 10
The commonest is female A aegypti (tiger mosquito). Unlike others it is primarily a daytime feeder: early in morning & before dusk. It lives near urban habitats & breeds mostly in man-made containers A albopictus, less common in Asia; has spread to N America & Europe. It is highly adaptive & can survive cold. It hibernates. Most active 5-6pm & 8-9am (2hours) A aegypti (5mm) A albopictus
Global burden of DF Underreported & misclassified • 390 million/y (25% clinical) • Incidence has grown x30 in recent decades • 50% global population is now at risk • <1970, only 9 countries had DF. Now >100. The Americas, SEA & W. Pacific are worst affected • DF spreads to new areas with explosive outbreaks • For a given country: DF knows only the entry but not the exit • In Europe first cases were reported in France & Croatia in 2010 & imported cases in 3 other countries 12
• 2012: outbreak occurred on Madeira islands (Portugal) & imported cases were detected in mainland Portugal & 10 other countries in Europe • 2013 saw outbreak in Florida & Yunnan; Costa Rica, Honduras & Mexico, Laos. Singapore has more cases after a lapse of several years • 2014: more cases in China, Cook Islands, Fiji, Malaysia & Vanuatu, Tonga & French Polynesia. DF was also reported in Japan after >70y • 2015: more cases occurred in Brazil & neighbors; worst outbreak in Delhi 13
14 Regions affected DF 2001
Global dengue burden, 2014
Dengue Virus • Arbovirus, flavivirus: 4 serotypes • Induces cytokines in cells with effects on endothelia in: – Heart, Liver, Kidneys, Lungs – Gut, Spleen, LN, Brain, Skin Causes increased permeability But no inflammation!
LC of flavivirus
Transmission • Within mosquito replication (extrinsic IP: 8-10d). It can transmit for the rest of vector’s life (2-3w) • Within humans (reservoir). Transmit for 4–5d (12d) after onset of disease. SS appear 4-7d (3-14d) (intrinsic IP) • Viremia starts slightly before SS; may last 3-10d (5d). The illness persists several days after the viremia has ended 21
22 Transmission Infected person Healthy person Infected mosquito IP: 3-14d Most commonly 4-7d
• Depends on the host immune response • Primary inf. is usually benign; but, 2y inf. with different serotype(s) within 3mo may cause DHF/DSS Antibody-dependent enhancement: by non- neutralizing, cross-reactive Ab from a primary inf., cause a heavy viral load: multisystem spread • Memory T cells & cytokines (INF-gamma, TNF-alpha, IL- 10) cause vascular leakage. No inflam.! Complements are reduced by NS1 Pathogenesis
• Hallmark of DHF: transient dysfunction of endoth.: leakage: (raised hct., low albumin, pl. effusions, ascites, hge., (thrombocytopenia & coagulation d.) • Loss of intravascular fluid causes hypoperfusion (lactic acidosis), hypoglycemia, hypoCa; finally, multi-organ failure • Infants can have DHF during a primary inf. due to transplacental antibodies Pathogenesis …
• Inf. with 1 serotype gives life-long immunity only for that with a very brief period of partial cross immunity (3mo) • Subsequent inf. by other serotypes increase the risk DHF • Everyone can be inf. by all 4. Several serotypes can be in circulation during an epidemic • Differential targeting of specific vascular beds triggers local vascular hyperpermeability No generalized edema! Pathogenesis …
3 Cl. Syndromes of DF: 1. Undifferentiated fever; 2. Classic DF 3. Severe DF: DHF, DSS Case Definition for DF an ac. viral biphasic F, frequently presenting with HA, bone/joint & muscular pains, rash, & leucopenia
DF VIRUS INFECTION Asymptomatic Symptomatic Undiffrentiated fever (viral syndrome) DF DF Haemorrhagic fever No Shock DF Shock Syndrome (DSS) (Plasma leakage)DF DF Haemorrhagic fever
29 SS Classical DF a severe, ILI that affects infants, young children & adults • Suspect DF if a HGF (40°C) is accompanied by any 2 of: severe HA, pain behind eyes, backache, muscle & joint pains, NV, swollen glands or rash on 3rd/4th d • Age: commonly 2-7y • Duration of illness: 2–7d • F: 3-5d • Slight gum & nasal bleeding • Pts. may also have itching, altered taste, particularly a metallic taste, extreme fatigue & severe depression
Skin rash Symptoms
4 Dx Criteria for DHF • Fever/recent F • Bleeds: skin, gum, nose, GIT, urine, menstruation • Low platelet (<100,000/mm3) • Leaky capillaries: raised hct. (≥20% over baseline) • low albumin • pleural or other effusions 4 Grades of DHF Grade 1: +ve tourniquet test Grade 2: above + spontaneous bleeding Grade 3: above + circulatory failure Grade 4: above + profound shock
Warning Signs of DHF 3–7d after onset with a fall in temp.: severe AP, HA, F., rash, persistent vomiting, tachypnea, bleeding gums/nose, fatigue, restlessness & internal hge All these show impending shock & should alert clinicians: close observation & fluids • The next 48h is critical for organ failure 34
Definition for DSS: DHF + • Evidence of shock: pinched face, sunken eyes, rapid thready pulse, cold clammy skin, beads of sweats on face, narrow pulse pressure (<20mmHg), hge., hypotension, low urine, late cap.refill, & altered mentation SS of Encephalitis/Encephalopathy in DF • Decreased consciousness: lethargy, confusion, coma • Seizures • Nuchal rigidity • Paresis
DHF causes death through dysfunction of endothelium (shock) & coagulopathy
Dx of DF • Direct: DENV isolation, genome detection (PCR), Ag. detection • Indirect: IgM & IgG – IgM to DENV or a ≥x4 rise in IgG in paired sample (ac. & convalescence serum) • Reverse transcription PCR (RT-PCR) & Ab (65.9%). PCR during first 5d of SS and/or early conval. (>5d) • NS1 & Ab (62.0%) Sample: serum or autopsy tissues
• Pts. who have IgM but a negative RT–PCR have probably a recent DF. IgM may remain elevated for 2-3mo • Also, there is cross reactivity with W. Nile V, St. Louis encephalitis V, Japanese Encephalitis V, Yellow FV. Dr should review past illness, recent travel, vax. record (especially YF) to Dx DF • Often paired specimens are needed for Dx. as Ag & IgM may be undetectable initially
Dx of DF ..,.
Flavivirus replication complex
42 Treatment No specific Rx. • For severe DF, medical care can decrease MR to <1% • Maintenance of fluid is critical • Classical DF recovers in 11d • DHF: intensive supportive Rx No NSAIDs: worsen the hemorrhage
DHF: emergency! • IVF is the essential & is the sole intervention: isotonic, for effective circulation. Boluses of 10−20 ml/kg/h for a limited period under close supervision; can avoid pulmonary edema • Blood transfusion • Follow urine output • In shock, colloid solution is preferred • Hct. before & after IVF. Basal Hct: 35−40% in adult females, 40−45% in males
Goals of fluid resuscitation: • improving circulation: less Hct., improving BP & pulse pressure, warm & pink limbs, a cap-refill <2sec • improving end-organ perfusion: stable mentation, urine ≥0.5ml/kg/h or decreasing metabolic acidosis • Later, IVF is given 10ml/kg/h for 1−2h; then 7ml/kg/h x2−4h & finally 3-5ml/kg/h for 24−48h
Prognosis • DF is typically self-limiting. CFR: <1% • Untreated, CFR: 50% • Usually recover without sequelae with serotype immunity • Factors for severity: age, preg., nutritional status, ethnicity, inf. with different serotypes, virus genotype, quality & extent of available medical care
46 Prevention & control Only by combating vector: Prevention of Mosquito Bites: • avoid going out when vector feeds • wear light-colored, long-sleeved clothing & trousers • mosquito-repellents over exposed parts of body & clothes every 4-6h
47 Prevention of Mosquito Bites Your accommodation should be air-conditioned or have mosquito nets Use insecticides or coil incenses
48 Elimination of Mosquitoes The most effective way is to keep environment clean & to remove stagnant water Cover water containers tightly so that mosquitoes can’t get in to lay eggs.
49 Elimination of Mosquitoes • Dispose of domestic wastes properly to prevent stagnant water • Dispose of empty bottles, cans & lunchboxes properly
50 Elimination of Mosquitoes • Change water for vases & aquatic plants/w, leaving no water under the pots or in the bottom saucers • Scrub the container surfaces thoroughly to prevent mosquito eggs sticking on them
51 Elimination of Mosquitoes Remove or puncture any dumped tyres to prevent the accumulation of stagnant water
52 Elimination of Mosquitoes Ditches should be free from blockage. Fill up uneven ground to prevent stagnant water
53 Elimination of Mosquitoes Remove stagnant water immediately if mosquitoes are found to be breeding. Use environmentally friendly insecticides such as lavicidal oil if necessary Biological controls such as keeping fishes to eat mosquito larvae would be a good option
Potential Breeding Sites
• Cover rarely used gully traps. Replace the gully trap with non-perforated ones & install anti-mosquito valves.
Prevention includes use of bug spray & other mosquito preventatives
WHO • provides technical support & guidance for effective management of DF outbreaks • supports to improve reporting systems & capture the true burden of the disease • provides training on Rx, Dx & vector control • formulates evidence-based strategies & policies • develops new tools, including insecticide products & application technologies • gathers official records of DF & severe DF from over 100 Member States • publishes guidelines & handbooks for case Mx, prevention & control for Member States
64 Immunization • Vaccine available
C H I K U N G U N Y A Facts a mosquito-borne RNA viral d. 1st reported in Tanzania 1952 • Means “to be contorted”, stooped due to severe arthralgia, fever; myalgia, HA,, nausea, fatigue & rash • Usually not fatal • Arthralgia is often debilitating & varies in duration • C. shares some SS with DF & zika • C. mostly occurs in Africa, Asia & Indian sub-. But a major outbreak; 2015 affected several countries in Americas No cure!
Signs & Symptoms Typical: abrupt F, frequent arthralgia, myalgia, HA, nausea, fatigue & rash. Arthralgia is often debilitating, but usually lasts for a few days. May be prolonged: acute, subacute or chronic • Often mild & unrecognized, or be misdiagnosed in areas where DF occurs • Most recover fully. Some have joint pain for several mo., or even years • Rarely eye, neurological & heart complications are reported as well as GI complaints. Serious complications are not common; but in elderly, death may occur
Transmission • C. has been identified in >60 countries • Most commonly by A aegypti & A albopictus (also DF) • Vectors usually bite outdoors, but A aegypti will also readily feed indoors • IP: usually 4-8d (2-12d) A aegypti (5mm) A albopictus
More about Disease Vectors • Both vectors cause large outbreaks • A aegypti is confined in tropics & sub-. But A albo. also lives in temperate & even cold temperate. A aegypti is more closely a/with human habitation & uses indoor breeding sites: flower vase, water vessels & water tanks, as well as same artificial outdoor habitats as A albo. • A albopictus thrives in a wider range of water-filled breeding sites than A aegypti: coconut husks, cocoa pods, bamboo stumps, tree holes, rock pools, tires, etc. So, it is abundant in rural as well as peri-urban areas
Diagnosis • Confirmed by IgM & IgG anti-C. Ab. & RT-PCR during the first week • IgM is highest 3-5w after onset (~2 mo.) • RT-PCR during the first week. RT–PCR samples may also be used for genotyping, allowing comparisons with virus samples from various areas • C. virus may be isolated from blood in first few d. of inf. • Treatment. No specific Rx. Supportive only
R a r e complications in C. At risk: neonates exposed intrapartum, age >65y, & HTN, DM, CV diseases or other illnesses: • uveitis, retinitis • myocarditis, hepatitis, nephritis • bullous skin lesions, hge • Meningoencephalitis, myelitis, GBS, & cr. nerve palsies • Some may have relapse of polyarthralgia, polyarthritis, tenosynovitis in the months following acute illness • Mortality is rare & occurs mostly in elderlies
Prevention & Control relies heavily on reducing natural & artificial habitats • Outbreaks: insecticides may be sprayed to surfaces in & around containers. Treat water in these to kill larvae • Protection during outbreaks: full dress, repellents on skin or clothing • Insecticide-treated mosquito nets afford good protection. Mosquito coils or vaporizers may also reduce biting • Basic precautions should be taken by people travelling to risk areas (repellents, long sleeves & pants & rooms with screens) No vaccine
Disease Outbreaks • 1999–00: DR Congo & in 2007 Gabon had a large outbreak • 2005: a major outbreak occurred in islands of I. Ocean, causing a large number of imported cases in Europe • 2006-7: India had a large outbreak. Several SEA countries were also affected • Since 2005: India, Indonesia, Maldives, Myanmar & Thailand have reported >1.9 million • 2007: 1st local C. was reported in Italy (197 cases). It confirmed that outbreaks by A albopictus are plausible in Europe
Countries where chikungunya has been reported (2016)
• 2013: France reported 2 confirmed autochthonous cases in the French Caribbean island St Martin. Since then, local transmission has been confirmed in over 43 countries & territories in Americas • 2014: France confirmed 4 local cases. Outbreaks were reported in the Pacific islands, Senegal, India • 2015: >1,379,788 cases of C. were recorded in Caribbean islands, LatAm countries, & the USA with 191 deaths Canada, Mexico & USA have also imported cases Disease Outbreaks …
• 2015: In Americas, >693k C. were reported, Colombia bore the biggest burden. It was >1 million in 2014 • 2016: >349k C. cases reported; most in Brazil, Bolivia & Colombia. First time autochthonous transmission was reported in Argentina (>1,000 cases). In Africa: Kenya reported an outbreak (>1,700 ) • 2017: Pakistan had a continued outbreak starting in 2016. Bangladesh also had a large outbreak Disease Outbreaks …
WHO Response for Chikungunya • formulates evidence-based outbreak management plans • provides technical support & guidance • supports improve reporting systems • provides training on Dx & Rx & vector control & publishes guidelines & handbooks on these • Encourages to develop social communication strategies to reduce mosquito vectors
Mosquito-borne d. 1 of the deadliest animals; cause millions of deaths/y • Malaria alone kills >1 million/y; a child/30 sec. • DF has risen x30 in the past 30y, & more countries affected • Aedes: Zika, DF, chikungunya, & YF, filariasis, Rift Valley F • Culex: West Nile virus, Japanese encephalitis, filariasis • Anopheles: malaria, filariasis • >half of world’s popn. live in areas where it is present • Sustained mosquito control is essential
Vector-borne diseases Facts • VBD cause >17% of all IDs • >700k deaths/y • >3.9 billion people in >128 countries are at risk of DF, with 96 million cases/y • Chagas d., leishmaniasis & schistosomiasis affect hundreds of millions • Many of these are preventable
Vector-borne Diseases • VBD are c/by parasites, viruses & bacteria • Major VBD, together, account for 17% of IDs • Burden is highest in tropics & sub- . VBD affect the poorest. Since 2014, major outbreaks of DF, malaria, C., YF & Zika have claimed lives & overwhelmed health systems • Distribution of VBD is determined by complex demographic, environmental & social factors. Global travel & trade, unplanned urbanization & climate change can impact on transmission, making period longer or more intense or causing d. to emerge in de-novo countries
Main vectors & d. they transmit • Vectors can transmit ID between humans or from animals to humans • Many are bloodsucking insects, which ingest pathogens during a blood meal from a host (human or animal) & later inject it into a new host • Mosquitoes are the best known vector. Others include ticks, flies, sandflies, fleas, triatomine bugs & some freshwater aquatic snails
• Mosquitoes – Aedes: – Anopheles: – Culex: • Sandflies: Leishmaniasis, Sandfly F (phelebotomus F) • Ticks: – Crimean-Congo haemorrhagic F – Lyme d – Relapsing F (borreliosis) – Rickettsial d. (spotted F &Q F) – Tick-borne encephalitis – Tularaemia
• Triatomine bugs – Chagas d (American trypanosomiasis) • Tsetse flies – Sleeping sickness (African trypanosomiasis) • Fleas – Plague (fleas from rats to humans) – Rickettsiosis • Black flies – Onchocerciasis (river blindness) • Aquatic snails – Schistosomiasis (bilharziasis) • Lice – Typhus & louse-borne relapsing F
• Changes in agricultural practices due to variation in temp. & rainfall can affect the transmission of VBD • The growth of urban slums, lacking reliable piped water or adequate solid waste management, can render large populations in towns & cities at risk of viral d. spread by mosquitoes • Together, such factors influence the reach of vector populations & the transmission patterns of disease- causing pathogens Vector-borne Diseases …
থপাটগ ল্যাতের জাপাথে মযাতপল্, অতেক পুতরাতো একটি গাছ। েতব অেযােয মাতসর েু ল্োে বসন্ত এবং গ্রীষ্মকাতল্ এ গাতছর থসৌন্দর্গ থবশী ফু তট উতে। এই গাতছর বাহাথর রঙ মােুষতক আকৃ ষ্ট কতর।
Dengue and chikungunya f

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Dengue and chikungunya f

  • 2.
    পৃথিবীর সবচাইতে সুন্দরগাছ. জাপাতেI ওতেতেথরো:বযাপক আকাতরর । সারা পৃথিবী থিতক অসংখ্য মােুষ এই গাছ থেখ্তে আতস। ১৯৯০ বগগ ফু ট
  • 5.
  • 6.
    History of DF •1780: epidemics in in Asia, Africa, N America • First in Bangladesh in 1964 (Dacca Fever) • 1968: a small outbreak occurred in border with Myanmar • In India DF was first recorded in 1812. A double peak hemorrhagic F epidemic occurred in Calcutta 1963-64 • In N Delhi, outbreaks reported in 1967, 1970, 1982, 1996
  • 7.
    Overview of DengueFever The commonest mosquito-borne viral disease • Aka ‘break bone fever’, Dandy fever • A multisystem inf. with wide clinical spectrum: ILI to fatal • Found in tropical & sub-tropical, mostly in urban & semi-urban areas • Risks: rainfall, temp., unplanned rapid urbanization • Severe DF is a leading c/of serious illness & death among children in some Asian & LatAm countries Aka: also known as. ILI: influenza like illness 7 Probably from Spanish, probably of African origin; compare Swahili kidinga
  • 9.
    • Despite itscomplex features, Rx is relatively simple, cheap & very effective if timely done. Maintenance of body fluid is critical in severe DF • The success key is early Dx & knowing its different phases • Rx at the primary & secondary levels are critical. A well- managed front-line response reduces admissions • No specific Rx. • Fatality <1% • Prevention & control depends on effective vector control measures
  • 10.
    • Vectors: mainlyfemale A aegypti, less: A albopictus • 4 closely related serotypes: DENV-1, -2, -3, -4 • Every serotype can cause severe & fatal disease • Recovery from 1 gives lifelong immunity against that. Cross-immunity to another serotypes is partial & temporary: subsequent inf. by that increases the risk of severe DF • 500,000 DHF are admitted/y: a large portion are children • Death: 10,000/y 10
  • 11.
    The commonest isfemale A aegypti (tiger mosquito). Unlike others it is primarily a daytime feeder: early in morning & before dusk. It lives near urban habitats & breeds mostly in man-made containers A albopictus, less common in Asia; has spread to N America & Europe. It is highly adaptive & can survive cold. It hibernates. Most active 5-6pm & 8-9am (2hours) A aegypti (5mm) A albopictus
  • 12.
    Global burden ofDF Underreported & misclassified • 390 million/y (25% clinical) • Incidence has grown x30 in recent decades • 50% global population is now at risk • <1970, only 9 countries had DF. Now >100. The Americas, SEA & W. Pacific are worst affected • DF spreads to new areas with explosive outbreaks • For a given country: DF knows only the entry but not the exit • In Europe first cases were reported in France & Croatia in 2010 & imported cases in 3 other countries 12
  • 13.
    • 2012: outbreakoccurred on Madeira islands (Portugal) & imported cases were detected in mainland Portugal & 10 other countries in Europe • 2013 saw outbreak in Florida & Yunnan; Costa Rica, Honduras & Mexico, Laos. Singapore has more cases after a lapse of several years • 2014: more cases in China, Cook Islands, Fiji, Malaysia & Vanuatu, Tonga & French Polynesia. DF was also reported in Japan after >70y • 2015: more cases occurred in Brazil & neighbors; worst outbreak in Delhi 13
  • 14.
  • 17.
  • 18.
    Dengue Virus • Arbovirus,flavivirus: 4 serotypes • Induces cytokines in cells with effects on endothelia in: – Heart, Liver, Kidneys, Lungs – Gut, Spleen, LN, Brain, Skin Causes increased permeability But no inflammation!
  • 20.
  • 21.
    Transmission • Within mosquitoreplication (extrinsic IP: 8-10d). It can transmit for the rest of vector’s life (2-3w) • Within humans (reservoir). Transmit for 4–5d (12d) after onset of disease. SS appear 4-7d (3-14d) (intrinsic IP) • Viremia starts slightly before SS; may last 3-10d (5d). The illness persists several days after the viremia has ended 21
  • 22.
  • 23.
    • Depends onthe host immune response • Primary inf. is usually benign; but, 2y inf. with different serotype(s) within 3mo may cause DHF/DSS Antibody-dependent enhancement: by non- neutralizing, cross-reactive Ab from a primary inf., cause a heavy viral load: multisystem spread • Memory T cells & cytokines (INF-gamma, TNF-alpha, IL- 10) cause vascular leakage. No inflam.! Complements are reduced by NS1 Pathogenesis
  • 25.
    • Hallmark ofDHF: transient dysfunction of endoth.: leakage: (raised hct., low albumin, pl. effusions, ascites, hge., (thrombocytopenia & coagulation d.) • Loss of intravascular fluid causes hypoperfusion (lactic acidosis), hypoglycemia, hypoCa; finally, multi-organ failure • Infants can have DHF during a primary inf. due to transplacental antibodies Pathogenesis …
  • 26.
    • Inf. with1 serotype gives life-long immunity only for that with a very brief period of partial cross immunity (3mo) • Subsequent inf. by other serotypes increase the risk DHF • Everyone can be inf. by all 4. Several serotypes can be in circulation during an epidemic • Differential targeting of specific vascular beds triggers local vascular hyperpermeability No generalized edema! Pathogenesis …
  • 27.
    3 Cl. Syndromesof DF: 1. Undifferentiated fever; 2. Classic DF 3. Severe DF: DHF, DSS Case Definition for DF an ac. viral biphasic F, frequently presenting with HA, bone/joint & muscular pains, rash, & leucopenia
  • 28.
    DF VIRUS INFECTION AsymptomaticSymptomatic Undiffrentiated fever (viral syndrome) DF DF Haemorrhagic fever No Shock DF Shock Syndrome (DSS) (Plasma leakage)DF DF Haemorrhagic fever
  • 29.
    29 SS Classical DF asevere, ILI that affects infants, young children & adults • Suspect DF if a HGF (40°C) is accompanied by any 2 of: severe HA, pain behind eyes, backache, muscle & joint pains, NV, swollen glands or rash on 3rd/4th d • Age: commonly 2-7y • Duration of illness: 2–7d • F: 3-5d • Slight gum & nasal bleeding • Pts. may also have itching, altered taste, particularly a metallic taste, extreme fatigue & severe depression
  • 31.
  • 32.
    4 Dx Criteriafor DHF • Fever/recent F • Bleeds: skin, gum, nose, GIT, urine, menstruation • Low platelet (<100,000/mm3) • Leaky capillaries: raised hct. (≥20% over baseline) • low albumin • pleural or other effusions 4 Grades of DHF Grade 1: +ve tourniquet test Grade 2: above + spontaneous bleeding Grade 3: above + circulatory failure Grade 4: above + profound shock
  • 34.
    Warning Signs ofDHF 3–7d after onset with a fall in temp.: severe AP, HA, F., rash, persistent vomiting, tachypnea, bleeding gums/nose, fatigue, restlessness & internal hge All these show impending shock & should alert clinicians: close observation & fluids • The next 48h is critical for organ failure 34
  • 35.
    Definition for DSS: DHF+ • Evidence of shock: pinched face, sunken eyes, rapid thready pulse, cold clammy skin, beads of sweats on face, narrow pulse pressure (<20mmHg), hge., hypotension, low urine, late cap.refill, & altered mentation SS of Encephalitis/Encephalopathy in DF • Decreased consciousness: lethargy, confusion, coma • Seizures • Nuchal rigidity • Paresis
  • 36.
    DHF causes deaththrough dysfunction of endothelium (shock) & coagulopathy
  • 37.
    Dx of DF •Direct: DENV isolation, genome detection (PCR), Ag. detection • Indirect: IgM & IgG – IgM to DENV or a ≥x4 rise in IgG in paired sample (ac. & convalescence serum) • Reverse transcription PCR (RT-PCR) & Ab (65.9%). PCR during first 5d of SS and/or early conval. (>5d) • NS1 & Ab (62.0%) Sample: serum or autopsy tissues
  • 38.
    • Pts. whohave IgM but a negative RT–PCR have probably a recent DF. IgM may remain elevated for 2-3mo • Also, there is cross reactivity with W. Nile V, St. Louis encephalitis V, Japanese Encephalitis V, Yellow FV. Dr should review past illness, recent travel, vax. record (especially YF) to Dx DF • Often paired specimens are needed for Dx. as Ag & IgM may be undetectable initially
  • 39.
  • 40.
  • 42.
    42 Treatment No specific Rx. •For severe DF, medical care can decrease MR to <1% • Maintenance of fluid is critical • Classical DF recovers in 11d • DHF: intensive supportive Rx No NSAIDs: worsen the hemorrhage
  • 43.
    DHF: emergency! • IVFis the essential & is the sole intervention: isotonic, for effective circulation. Boluses of 10−20 ml/kg/h for a limited period under close supervision; can avoid pulmonary edema • Blood transfusion • Follow urine output • In shock, colloid solution is preferred • Hct. before & after IVF. Basal Hct: 35−40% in adult females, 40−45% in males
  • 44.
    Goals of fluidresuscitation: • improving circulation: less Hct., improving BP & pulse pressure, warm & pink limbs, a cap-refill <2sec • improving end-organ perfusion: stable mentation, urine ≥0.5ml/kg/h or decreasing metabolic acidosis • Later, IVF is given 10ml/kg/h for 1−2h; then 7ml/kg/h x2−4h & finally 3-5ml/kg/h for 24−48h
  • 45.
    Prognosis • DF istypically self-limiting. CFR: <1% • Untreated, CFR: 50% • Usually recover without sequelae with serotype immunity • Factors for severity: age, preg., nutritional status, ethnicity, inf. with different serotypes, virus genotype, quality & extent of available medical care
  • 46.
    46 Prevention & control Onlyby combating vector: Prevention of Mosquito Bites: • avoid going out when vector feeds • wear light-colored, long-sleeved clothing & trousers • mosquito-repellents over exposed parts of body & clothes every 4-6h
  • 47.
    47 Prevention of MosquitoBites Your accommodation should be air-conditioned or have mosquito nets Use insecticides or coil incenses
  • 48.
    48 Elimination of Mosquitoes Themost effective way is to keep environment clean & to remove stagnant water Cover water containers tightly so that mosquitoes can’t get in to lay eggs.
  • 49.
    49 Elimination of Mosquitoes •Dispose of domestic wastes properly to prevent stagnant water • Dispose of empty bottles, cans & lunchboxes properly
  • 50.
    50 Elimination of Mosquitoes •Change water for vases & aquatic plants/w, leaving no water under the pots or in the bottom saucers • Scrub the container surfaces thoroughly to prevent mosquito eggs sticking on them
  • 51.
    51 Elimination of Mosquitoes Removeor puncture any dumped tyres to prevent the accumulation of stagnant water
  • 52.
    52 Elimination of Mosquitoes Ditchesshould be free from blockage. Fill up uneven ground to prevent stagnant water
  • 53.
    53 Elimination of Mosquitoes Removestagnant water immediately if mosquitoes are found to be breeding. Use environmentally friendly insecticides such as lavicidal oil if necessary Biological controls such as keeping fishes to eat mosquito larvae would be a good option
  • 54.
  • 60.
    • Cover rarelyused gully traps. Replace the gully trap with non-perforated ones & install anti-mosquito valves.
  • 62.
    Prevention includes useof bug spray & other mosquito preventatives
  • 63.
    WHO • provides technicalsupport & guidance for effective management of DF outbreaks • supports to improve reporting systems & capture the true burden of the disease • provides training on Rx, Dx & vector control • formulates evidence-based strategies & policies • develops new tools, including insecticide products & application technologies • gathers official records of DF & severe DF from over 100 Member States • publishes guidelines & handbooks for case Mx, prevention & control for Member States
  • 64.
  • 65.
    C H IK U N G U N Y A Facts a mosquito-borne RNA viral d. 1st reported in Tanzania 1952 • Means “to be contorted”, stooped due to severe arthralgia, fever; myalgia, HA,, nausea, fatigue & rash • Usually not fatal • Arthralgia is often debilitating & varies in duration • C. shares some SS with DF & zika • C. mostly occurs in Africa, Asia & Indian sub-. But a major outbreak; 2015 affected several countries in Americas No cure!
  • 67.
    Signs & Symptoms Typical:abrupt F, frequent arthralgia, myalgia, HA, nausea, fatigue & rash. Arthralgia is often debilitating, but usually lasts for a few days. May be prolonged: acute, subacute or chronic • Often mild & unrecognized, or be misdiagnosed in areas where DF occurs • Most recover fully. Some have joint pain for several mo., or even years • Rarely eye, neurological & heart complications are reported as well as GI complaints. Serious complications are not common; but in elderly, death may occur
  • 72.
    Transmission • C. hasbeen identified in >60 countries • Most commonly by A aegypti & A albopictus (also DF) • Vectors usually bite outdoors, but A aegypti will also readily feed indoors • IP: usually 4-8d (2-12d) A aegypti (5mm) A albopictus
  • 73.
    More about DiseaseVectors • Both vectors cause large outbreaks • A aegypti is confined in tropics & sub-. But A albo. also lives in temperate & even cold temperate. A aegypti is more closely a/with human habitation & uses indoor breeding sites: flower vase, water vessels & water tanks, as well as same artificial outdoor habitats as A albo. • A albopictus thrives in a wider range of water-filled breeding sites than A aegypti: coconut husks, cocoa pods, bamboo stumps, tree holes, rock pools, tires, etc. So, it is abundant in rural as well as peri-urban areas
  • 75.
    Diagnosis • Confirmed byIgM & IgG anti-C. Ab. & RT-PCR during the first week • IgM is highest 3-5w after onset (~2 mo.) • RT-PCR during the first week. RT–PCR samples may also be used for genotyping, allowing comparisons with virus samples from various areas • C. virus may be isolated from blood in first few d. of inf. • Treatment. No specific Rx. Supportive only
  • 76.
    R a re complications in C. At risk: neonates exposed intrapartum, age >65y, & HTN, DM, CV diseases or other illnesses: • uveitis, retinitis • myocarditis, hepatitis, nephritis • bullous skin lesions, hge • Meningoencephalitis, myelitis, GBS, & cr. nerve palsies • Some may have relapse of polyarthralgia, polyarthritis, tenosynovitis in the months following acute illness • Mortality is rare & occurs mostly in elderlies
  • 77.
    Prevention & Control reliesheavily on reducing natural & artificial habitats • Outbreaks: insecticides may be sprayed to surfaces in & around containers. Treat water in these to kill larvae • Protection during outbreaks: full dress, repellents on skin or clothing • Insecticide-treated mosquito nets afford good protection. Mosquito coils or vaporizers may also reduce biting • Basic precautions should be taken by people travelling to risk areas (repellents, long sleeves & pants & rooms with screens) No vaccine
  • 78.
    Disease Outbreaks • 1999–00:DR Congo & in 2007 Gabon had a large outbreak • 2005: a major outbreak occurred in islands of I. Ocean, causing a large number of imported cases in Europe • 2006-7: India had a large outbreak. Several SEA countries were also affected • Since 2005: India, Indonesia, Maldives, Myanmar & Thailand have reported >1.9 million • 2007: 1st local C. was reported in Italy (197 cases). It confirmed that outbreaks by A albopictus are plausible in Europe
  • 79.
    Countries where chikungunyahas been reported (2016)
  • 80.
    • 2013: Francereported 2 confirmed autochthonous cases in the French Caribbean island St Martin. Since then, local transmission has been confirmed in over 43 countries & territories in Americas • 2014: France confirmed 4 local cases. Outbreaks were reported in the Pacific islands, Senegal, India • 2015: >1,379,788 cases of C. were recorded in Caribbean islands, LatAm countries, & the USA with 191 deaths Canada, Mexico & USA have also imported cases Disease Outbreaks …
  • 81.
    • 2015: InAmericas, >693k C. were reported, Colombia bore the biggest burden. It was >1 million in 2014 • 2016: >349k C. cases reported; most in Brazil, Bolivia & Colombia. First time autochthonous transmission was reported in Argentina (>1,000 cases). In Africa: Kenya reported an outbreak (>1,700 ) • 2017: Pakistan had a continued outbreak starting in 2016. Bangladesh also had a large outbreak Disease Outbreaks …
  • 82.
    WHO Response forChikungunya • formulates evidence-based outbreak management plans • provides technical support & guidance • supports improve reporting systems • provides training on Dx & Rx & vector control & publishes guidelines & handbooks on these • Encourages to develop social communication strategies to reduce mosquito vectors
  • 83.
    Mosquito-borne d. 1 ofthe deadliest animals; cause millions of deaths/y • Malaria alone kills >1 million/y; a child/30 sec. • DF has risen x30 in the past 30y, & more countries affected • Aedes: Zika, DF, chikungunya, & YF, filariasis, Rift Valley F • Culex: West Nile virus, Japanese encephalitis, filariasis • Anopheles: malaria, filariasis • >half of world’s popn. live in areas where it is present • Sustained mosquito control is essential
  • 84.
    Vector-borne diseases Facts • VBDcause >17% of all IDs • >700k deaths/y • >3.9 billion people in >128 countries are at risk of DF, with 96 million cases/y • Chagas d., leishmaniasis & schistosomiasis affect hundreds of millions • Many of these are preventable
  • 85.
    Vector-borne Diseases • VBDare c/by parasites, viruses & bacteria • Major VBD, together, account for 17% of IDs • Burden is highest in tropics & sub- . VBD affect the poorest. Since 2014, major outbreaks of DF, malaria, C., YF & Zika have claimed lives & overwhelmed health systems • Distribution of VBD is determined by complex demographic, environmental & social factors. Global travel & trade, unplanned urbanization & climate change can impact on transmission, making period longer or more intense or causing d. to emerge in de-novo countries
  • 86.
    Main vectors &d. they transmit • Vectors can transmit ID between humans or from animals to humans • Many are bloodsucking insects, which ingest pathogens during a blood meal from a host (human or animal) & later inject it into a new host • Mosquitoes are the best known vector. Others include ticks, flies, sandflies, fleas, triatomine bugs & some freshwater aquatic snails
  • 87.
    • Mosquitoes – Aedes: –Anopheles: – Culex: • Sandflies: Leishmaniasis, Sandfly F (phelebotomus F) • Ticks: – Crimean-Congo haemorrhagic F – Lyme d – Relapsing F (borreliosis) – Rickettsial d. (spotted F &Q F) – Tick-borne encephalitis – Tularaemia
  • 88.
    • Triatomine bugs –Chagas d (American trypanosomiasis) • Tsetse flies – Sleeping sickness (African trypanosomiasis) • Fleas – Plague (fleas from rats to humans) – Rickettsiosis • Black flies – Onchocerciasis (river blindness) • Aquatic snails – Schistosomiasis (bilharziasis) • Lice – Typhus & louse-borne relapsing F
  • 89.
    • Changes inagricultural practices due to variation in temp. & rainfall can affect the transmission of VBD • The growth of urban slums, lacking reliable piped water or adequate solid waste management, can render large populations in towns & cities at risk of viral d. spread by mosquitoes • Together, such factors influence the reach of vector populations & the transmission patterns of disease- causing pathogens Vector-borne Diseases …
  • 90.
    থপাটগ ল্যাতের জাপাথেমযাতপল্, অতেক পুতরাতো একটি গাছ। েতব অেযােয মাতসর েু ল্োে বসন্ত এবং গ্রীষ্মকাতল্ এ গাতছর থসৌন্দর্গ থবশী ফু তট উতে। এই গাতছর বাহাথর রঙ মােুষতক আকৃ ষ্ট কতর।