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Emerging and Re-emerging Infectious Diseases

Emerging and Re-emerging Infectious Diseases. INTRODUCTION RESPONSIBLE FACTORS CLASSIFICATION DISEASES OF CONCERN PREVENTION. INTRODUCTION :. INFECTIOUS DISEASES A ccounted for about 26% of the 57 million deaths worldwide in 2002 .

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Emerging and Re-emerging Infectious Diseases

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  1. Emerging andRe-emerging Infectious Diseases

  2. INTRODUCTION • RESPONSIBLE FACTORS • CLASSIFICATION • DISEASES OF CONCERN • PREVENTION

  3. INTRODUCTION : INFECTIOUS DISEASES • Accounted for about 26% of the 57 million deaths worldwide in 2002. • Remain among leading causes of death worldwide despite remarkable advances in medical research and treatments. • In addition, nearly 30% of all disability adjusted life years (DALYs) could be accounted to infectious diseases. • Emergence of new infectious diseases, re-emergence of old infectious diseases and persistence of intractable infectious diseases, all led to persistence and even increase in infectious diseases in many parts of the world .

  4. DEFINITIONS Emerging Infectious Diseases It includes outbreaks of previously unknown diseases or known diseases whose incidence in humans has significantly increased in the past two decades. Re-emerging Infectious Diseases These are the known diseases that have reappeared after a significant decline in incidence.

  5. “Are infectious diseases emerging more recently than before?“

  6. Major Factors Contributing to Emerging Infections: 1992 Human demographics and behavior Technology and Industry Economic development and land use International travel and commerce Microbial adaptation and change Breakdown of public health measures

  7. More Factors Contributing to Emerging Infections: 2003 • Human vulnerability • Climate and weather • Changing ecosystems • Poverty and social inequality • War and famine • Lack of political will • Intent to harm

  8. Emerging Infections:Human Demographics, Behavior, Vulnerability • More people, more crowding. • Changing sexual mores (HIV, STDs) • Injection drug use (HIV, Hepatitis C) • Changing eating habits: out more, more produce (food-borne infections) • More populations with weakened immune system: elderly, HIV/AIDS, cancer patients and survivors, persons taking antibiotics and other drugs.

  9. Emerging Infections:Technology and Industry • Mass food production (Campylobacter, E.coli O157:H7, etc…) • Use of antibiotics in food animals (antibiotic-resistant bacteria) • More organ transplants and blood transfusions (Hepatitis C, WNV,…) • New drugs for humans (prolonging immunosuppression) A big city on a sunny day

  10. Emerging Infections:Economic Development, Land Use, Changing Ecosystems • Changing ecology influencing waterborne, vector borne disease transmission (e.g. dams, deforestation) • Contamination of watershed areas by cattle (Cryptosporidium) • More exposure to wild animals and vectors (Lyme disease, erhlichiosis, babesiosis, …)

  11. Emerging Infections:International Travel and Commerce • Persons infected with an exotic disease anywhere in the world can be into your city within hours (SARS) • Foods from other countries imported routinely into your city (Cyclospora,….) • Vectors hitch-hiking on imported products (Asian tiger mosquitoes on bamboos….)

  12. Emerging Infections:Microbial Adaptation and Change • Increased antibiotic resistance with increased use of antibiotics in humans and animals (VRE, VRSA, penicillin- and macrolide-resistant Strep pneumoniae, multidrug-resistant Salmonella,….) • Increase virulence (Group A Strep) • Jumping species from animals to humans (avian influenza, HIV?, SARS?)

  13. Emerging Infections:Poverty, Social Inequality, Breakdown of Public Health Measures • Lack of basic hygienic infrastructure (safe water, safe foods, etc..) • Inadequate vaccinations (measles, diphtheria) • Discontinued mosquito control efforts (dengue, malaria) • Lack of monitoring and reporting (SARS)

  14. Emerging Infections:Intent to Harm • Bioterrorism: Anthrax in US 2001 • Bio-Crimes: Salmonella , Shigella • Potential agents: Smallpox, Botulism toxin, Plague, Tularemia, ….

  15. LIST OF EMERGING & RE-EMERGING DISEASES GROUP-1 PATHOGENS NEWLY RECOGNIZED IN LAST TWO DECADES • ACANTHAMOEBIASIS • BABESIOSIS • BARTONELLA HENSELE • EHERLICHIOSIS • CORONA VIRUS(SARS)

  16. CONTD… H.PYLORI HEPATITIS C HEPATITIS E HUMANHERPES VIRUS8(HHV8) HHV6 LYME BORRELIOSIS PARVOVIRUS B19

  17. GROUP-2 REMERGING PATHOGENS • ENTEROVIRUS71 • CLOSTRIDIUM DEFFICILE • COCCIDIOIDES IMMITIS • MUMPS VIRUS • PRION • STREPTOCOCCUS GROUP A • STAPHYLOCOCCUS AUREUS

  18. GROUP-3 AGENTS WITH BIOTERRORISM POTENTIAL CATEGORY A • B.anthracis • C.botulinum • Y.pestis • V.major • F.tulariensis • Hanta virus

  19. CATEGORY B • B.mallei • B.pseudomallei • C.brunetti • Brucella • Ricin toxin • Epsilon toxin(c.perfringens) • EnterotoxinB(staphylococcus) • Viral encephalitides(Japanese encephalitis virus,kyasanur forest virus)

  20. CONTD… FOOD &WATER BORNE DISEASES • BACTERIA(E.coli,Vibrio,shigella) • VIRUS(Hepatitis A,Calcivirus) • PROTOZOANS(Giardia,Entamoeba,Cryptosporidium)

  21. CATEGORY C • TICK BORN HAEMORRHAGIC FEVERS • TICK BORN ENCEPHALITIC FEVER • YELLOW FEVER • MDR TB & XDR TB • RABIES • SARS ASSOCIATED CORONAVIRUS • ANTIMICROBIAL RESISTANCE

  22. IMPORTANT RE-EMERGING DISEASES • TUBERCULOSIS • DENGUE FEVER • MALARIA • MENINGOCOCCAL MENINGITIS • BUBONIC PLAGUE • HANTA VIRUS PULMONARY SYNDROME

  23. HIV/AIDSPresent situation and challenges • HIV epidemic in SEAR mainly due to: • Unsafe sex • Injecting drug use • Poverty • Low literacy • Widespread stigma • Weak health systems. • India, Thailand, Myanmar, Indonesia and Nepal – account for the majority of the burden in the Region.

  24. SARS • A patient was admitted in Vietnam on 26th Feb. 2003 with respiratory illness and died in March 2003. • 7 health workers who cared for this patient also became ill on 5th March 2003. • Since then, the cases have been reported from many countries. • International travel facilitated its spread rapidly. • It was found that the disease initially emerged in China in November 2002. • The etiological agent is a virus -- isolated, but yet to be identified. Perhaps, it is a mutated strain of corona virus or a virus, which has jumped from an animal species to humans. • The infection is spread through droplets/aerosols. (It is also possible that SARS is transmitting through other unidentified routes.)

  25. AVIAN INFLUENZA REASONS FOR CONCERN ABOUT THE CURRENT OUTBREAKS • Most outbreaks caused by the highly pathogenic H5N1 strain • . • Strain has unique capacity to jump the species barrier & cause severe disease, with high mortality, in humans. • Gene swapping between the human & viruses inside the human body can give rise to a comavian pletely new subtype of the influenza virus to which Very few, if any, humans would have natural immunity.

  26. Sufficient human genes in virus direct man to man transmission Pandemic. • influenza pandemic of 1918–1919 when the virus spread around the globe in 4-6 months. • existing vaccines, would not be effective against completely new influenza virus.

  27. Every year 3 million people newly affected. over 500000 lose their lives. TuberculosisPresent situation • SEAR with 5million cases, has the highest number of TB cases among all WHO regions. • Bangladesh, India, Indonesia, Myanmar and Thailand are among the 22 high-burden countries in the world and together account for 95% of the TB burden in the Region. • TB -most common opportunistic infection among HIV-infected. • ~3 million people co-infected with HIV & TB.

  28. TB has emerged as MDR-TB & XDR-TB • About 50 million people worldwide are infected with drug resistant TB • % of MDR-TB in INDIA in 2004 was 2.4 among new cases • STOP TB STRATEGY adopted by WHO in 2006 focusses on prevention & control of MDR-TB & HIV -TB

  29. MalariaPresent situation and challenges PAST TWO DECADES The proportion of Plasmodium falciparum malaria has increased from 12% to more than 45%. Increasing resistance of Plasmodium falciparum to first- and second line anti- malarial drugs.

  30. MalariaPresent situation and challenges India reports the largest proportion of malaria cases in the Region. Annually there are approximately 100 million cases in SEAR PRESENTLY About 2.5 million cases and 4000 deaths per year.

  31. DENGUEPresent situation and challenges • Dengue has emerged as a serious public health problem over the last few decades. • Disease is spreading to new geographical areas, and frequency of outbreaks has increased. • During 2007, outbreaks have been reported from a number of countries in Asia including Thailand, Cambodia, Indonesia, Vietnam, Philippines and even in Singapore, which has one of the best dengue control programmes.

  32. PLAGUE • In SEAR, natural foci of plague- exist in INDIA, INDONESIA , MAYANMAR & NEPAL • No case was reported after 1966 in INDIA till it re-emerged in sept 2004 in MAHARASHTRA • 1997- outbreak of pneumonic plague in SURAT • 2002- 16 cases of pneumonic plague(4 deaths) in hatkoti , distt SHIMLA

  33. SCRUB TYPHUS • During world war II, an epidemic of scrub typhus occurred in ASSAM & WEST BENGAL. • 1970 -80,it was reported from INDIA, CHINA, JAPAN, INDONESIA & MALAYSIA. • In july,2008 ,outbreak occurred in some areas of HP.

  34. Response To “Threat” • Various international & national organizations have come together to combat this threat. • WHO, CDC, NIH, Department of Defense & FDA. • ALL work in collaboration to develop strategic plans to combat the microbial emergence and re-emergence.

  35. Prevention of Emerging Infectious Diseases Surveillance and Response Applied Research Infrastructure and Training Prevention and Control

  36. Surveillance • Global / Regional level laboratory surveillance • FLUNET : Surveillance network for monitoring influenza\ • RABNET : Surveillance network for rabies • PANCET : Pacific Public Health Services Network - to improve surveillance in pacific island.

  37. Surveillance • GPHIN : Global Public Intelligence Network • Antimicrobial resistance information bank Global / Regional level epidemiological surveillance. • International Health Regulations (IHR) mandatory reporting of certain infectious diseases eg. Cholera, plague, yellow fever • WHO Disease / rumor outbreak list - list unconfirmed disease outbreaks worldwide.

  38. Global & National Surveillance Systems / Networks At National Level - strong surveillance system is required to collect relevant, accurate & timely information of an outbreak. WHO – at Global Level- act as focal point for data exchange. WHO has recommended surveillance standards for 40 specific diseases and 8 syndromes. HIV/AIDS network – through sentinel sites Influenza network- Collects information from member laboratories to make decision regarding vaccine composition . Tuberculosis monitoring system- Produces reports on notification, results and the extent of implementation of DOTS . Global salmonella surveillance network .

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