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  • 1. EMERGING & RE-EMERGING [parasitic] INFECTIONSINIMMUNOCOMPETENT & IMMUNOCOMPROMISED HOSTS
    Rumala Morel
    Department of Parasitology
    Faculty of Medicine
    Peradeniya
    Year 3 2005/06 Batch
  • 2. Mad cow disease
    H5N1 avian influenza
    Severe Acute Respiratory Syndrome (SARS)
    Ebola virus
    Hantavirus
    Monkeypox
    Swine flu
    New Diseases Emerge
    Old Diseases Re-emerge
  • 3. Objectives
    Define emerging & re-emerging infections
    List the emerging & re-emerging parasitic infections which are important globally & in SL
    Briefly describe the factors which predispose to emergence & re-emergence of infections in immunocompetent & immunocompromised hosts
    Recognize the current handicaps when dealing with the risks of these infections
    Briefly describe the preventive aspects of these infections
  • 4. "emerging," "re-emerging," or "endemic"
    Re-emerging
    = diseases that once were major health problems globally or in a particular country, and then declined dramatically, but are again becoming health problems for a significant proportion of the population.
    Diseases thought to be adequately controlled making a “comeback” are “re-emerging”
    Emerging = diseases
    that have not occurred
    in humans before
    or
    that occurred only
    in small numbers
    in isolated places.
    "endemic"
    a long term problem.
    Never significantly declining
    Eg. pneumonia
  • 5. New Diseases Emerge
    Emerging diseases = new infections that arise from changes in existing organisms
    or
    known infections that spread to new geographic areas or populations
    Incidence of such a disease in people increases over 20 years or threatens to increase
    WHAT ARE EMERGING DISEASE
    ‘HOT SPOTS’?
    • Regions where new emerging infectious diseases are most likely to originate.
    • 6. Usually tropical – developing countries
    • 7. ill equipped to cope
  • Old Diseases Re-Emerge
    (A) EVOLUTION OF THE INFECTIOUS AGENT
    Mutations in bacterial genes that confer resistance to antibiotics – 20%
    Multidrug-resistant & extremely drug-resistant TB
    Multi drug resistant P.falciparum
    (B) REDUCED HUMAN IMMUNITY
    Immunization failure
    (breakdowns in public health measures)
    a greater proportion of susceptible individuals in a population and an increased reservoir of the infectious agent.
    Increased number of immunocompromised hosts - due to the stress of famine, war, or disease
  • 8. WHY EMERGE? FACTORS PREDISPOSING TO EMERGENCE
    1st step
    Introduction of an infection for the first time into the
    human population
    ZOONOSES
    In most cases (60%) that’s an infection that’s already out there in nature – may be a virus that’s naturally infecting some other species.
    Ecological changes - puts humans in contact with the virus. Usually due to human activities
  • 9. WHY EMERGE? FACTORS PREDISPOSING TO EMERGENCE
    ENVIRONMENTAL CHANGE
    tropical forests are cleared to make way for new roads, displacing disease-carrying animals and insects and increased human traffic through previously isolated areas
    URBANIZATION - person-to-person transmission
    POOR PRIMARY HEALTH CARE
    public health services may not be equipped to deal with some infectious outbreaks
  • 10. Globally important Emerging & Re-emerging Infectious Diseases
    EMERGING
    AIDS
    cholera
    CJD
    Ebola hemorrhagic fever
    influenza
    Legionnaire disease Lyme disease
    RE-EMERGING
    tuberculosis
    malaria
    schistosomiasis
  • 11. List of NIAID* Emerging and Re-emerging Diseases
    Group I—Pathogens Newly Recognized in the Past Two Decades
    Group II—Re-emerging Pathogens
    Group III—Agents with Bioterrorism Potential
    NIAID—Category A
    NIAID—Category B
    NIAID—Category C
    * NIAID = National Institute of Allergy & Infectious Diseases - USA
  • 12. Emerging and Re-emerging Parasites
    NIAID Group 1 - Pathogens newly recognized in past two decades
    • Acanthamoeba
    • 13. Microsporidia
    Encephalitozoon cuniculi Encephalitozoon hellem Enterocytozoon bieneusi
    NIAID Group 3 -
    Category B
    Food & Waterborne pathogens
    • Cryptosporidium parvum
    • 14. Cyclospora cayatanensis
    • 15. Giardia lamblia
    • 16. Entamoeba histolytica
    • 17. Toxoplasma gondii
  • Encephalitozoon cuniculi
    coiled polar filament,
    thin wall with
    endospore,
    and
    exospore
    extruded polar filament.
  • 18. What is a Pandemic?
    ????Panic & Epidemic???
    pandemic is a global disease outbreak
    "The world is now at the start of the 2009 influenza pandemic 30,000 confirmed cases from 74 countries” 11th June 2009
    WHO increases pandemic alert level to phase 6 "community level outbreaks in at least one other country in a different WHO region in addition to the criteria defined in Phase 5.
    " Phase 5 is characterized by human-to-human transmission of the virus into at least 2 countries in 1 WHO region.
    H1N1 immunization campaign
  • 19.
  • 20. Global Warming
    A temperature change of several degrees may make temperate zones more hospitable to vectors of tropical diseases
    Malaria, Dengue - mosquitoes
    Schistosomiasis – snails
    At the same time, tropical areas may become less hospitable to some of the same diseases.
  • 21.
  • 22. Schistosomiasis
    ? Spreading from
    TROPICAL to
    TEMPERATE regions
    Due to spread
    of snail vector
    With
    GLOBAL WARMING
  • 23. crayfish as a biocontrol agent for the
    snail vector of human schistosomiasis,
    a disease that has resurfaced
    as a growing problem due to
    China's rapid land-use change.
  • 24. Transmission ofpathogens with reduced dependence on host mobility
    water-borne –diarrhoeal agents
    attendant-borne [eg. Escherichia coli]
    Emerging hospital-acquired pathogens
    Humans create pathways for transmission
    eg. spreading HIV through needle sharing, blood transfusion, commercial sex trade. It is now pandemic in spite of its relatively inefficient transmission.
    mosquito-transmitted diseases: water is the limiting step.
    So irrigation projects, building of dams, cause an increase
    in the mosquito population, and suddenly you see an
    increase in the diseases
  • 25. MALARIA
    WHO Global Malaria Programme
    aims not only to reduce
    • the burden of malaria in endemic areas,
    but also to
    • Limit the geographical extent of malaria in the world.
    Local Elimination
    the complete interruption
    of mosquito-borne malaria transmission
    in a
    defined geographical area
  • 26. Key interventions to control malaria include:
    • prompt and effective treatment with
    artemisinin-based combination therapies;
    • use of insecticidal nets by people at risk;
    And
    • indoor residual spraying
    to control the vector mosquitoes.
  • 27. Emerging Parasitic Diseases in Sri Lanka
    Leishmaniasis
    Cryptosporidiosis
    Dirofilariasis
    Toxocariasis
    Cutaneous Larva Migrans
  • 28. Sand fly
    Cutaneous leishmaniasis is established
    Visceral leishmaniasis is
    Emerging in Sri Lanka
    Promastigotes
    Amastigotes
  • 29. Cutaneous leishmaniasis in Sri Lanka
  • 30.
  • 31.
  • 32. Since 1981, HIV/AIDS has infected
    60 million & killed half of them.
    2 million die every year &
    every 15 seconds a person is infected with HIV
  • 33. Control of HIV/AIDS
    “test and treat”
    strategy of universal,
    voluntary, annual HIV testing
    and immediate treatment for
    those who test positive.
    High-risk populations
    In SL
    CSWs, Drug users,
    Internal migrants
    and transport workers
    Global fund for AIDS/TB/Malaria ( GFATM)
    Community-based outreach
    strategies and new social-media
    tools like mobile phones,
    the Internet, Twitter, and Facebook
  • 34. Guidelines for Preventing Opportunistic Infections Among HIV-Infected Persons --- 2002Recommendations of the U.S. Public Health Service and the Infectious Diseases Society of America*
    (A) preventing first episodes of disease by chemoprophylaxis or vaccination (primary prophylaxis), and preventing disease recurrence (secondary prophylaxis).
    (B) PREVENTING EXPOSURE TO PATHOGENS
    oral-anal contact - to reduce the risk for intestinal infections e.g., cryptosporidiosis, shigellosis, campylobacteriosis, amebiasis, giardiasis, and hepatitis
    contact with animals - cryptosporidiosis, toxoplasmosis, salmonellosis, campylobacteriosis, or Bartonella infection.
  • 35. HIV infected - PREVENTING EXPOSURE TO PATHOGENS (contd)
    New pet – avoid animals aged <6 months or <1 year for cats –toxoplasmosis,cryptosporidiosis, Bartonella infection (avoid cat bite/scratches, flea control), salmonellosis, and campylobacteriosis
    Poultry and meat are safest when adequate cooking is confirmed with a thermometer (internal temperature of 180ºF for poultry and 165ºF for red meats). no trace of pink
    Uncooked meats should not be allowed to come in contact with other foods; hands, cutting boards, counters, and knives and other utensils should be washed thoroughly after contact with uncooked foods (BIII).
  • 36. Cryptosporidium parvum: an emerging pathogen
    six major outbreaks in the United States
    - contamination of drinking water
    • highly environmentally resistant cyst of
    C. parvum survives
    • drinking water filtrations
    • 37. chlorination
    • 38. oocysts do not survive cooking
    2 types of oocysts
    thick-walled - excreted
    thin-walled -autoinfection
  • 39. Cryptosporidium
  • 40. TRANSMISSION
    CLINICAL FEATURES
    feco-oral
    water contaminated by livestock mammal feces
    HIGH RISK GROUPS
    • infants and younger children in day-care centers -frequent diaper-changing
    • 41. those whose drinking water is unfiltered and untreated
    • 42. Farmers / veterinarians
    Watery diarrhea (up to 20 liters/day)
    dehydration, weight loss, abdominal pain, fever, nausea and vomiting. 
    In immunocompetent – self limited -1 to 2 wks
    immunocompromised
    chronic and severe diarrhoea
    Disseminated - lungs
    50% infective dose (ID50) of C. parvum
    is only 132 oocysts for healthy persons
  • 43. CRYPTOSPORDIOSIS
    Laboratory Diagnosis:Acid-fast staining
    immunofluorescence microscopy
    method of choice - greatest sensitivity and specificity
    enzyme immunoassays
    Molecular methods - research tool.
  • 44. THE U.S. PUBLIC HEALTH SERVICEAND INFECTIONS DISEASES SOCIETY OF AMERICABOTH RECOMMEND THAT HIV-INFECTED INDIVIDUALSSHOULD NOT BRING INTO THEIR HOMES:
    Animals with diarrheaStray dogs or catsDogs or cats under age 6 months
    TREATMENT OF CRYPTOSPORIDIOSIS
    Paromomycin.
  • 45. Cyclospora cayetanensis
  • 46. Life Cycle
    of
    Cyclospora
    cayetanensis
  • 47. Acanthameoba spp.
    Isolated from water, soil, air conditioning etc
    In healthy -
    Acanthamoeba
    keratitis
    Immunosuppressed -
    Granulomatous Amebic Encephalitis (GAE)
    Disseminated infection
  • 48. Emerging & Re-emerging Infectious Diseases Surveillance & Control
    Disease surveillance is concentrated not in developing countries, where emerging diseases are most likely to arise, but in developed countries that can afford laboratories
    Global disease surveillance networks
    (1) U.S. Defense Department’s GEIS
    (2) WHO - Global Outbreak Alert and Response Network (GOARN)
    Identify, confirm and respond to outbreaks of international importance.Emerging Pathogens Institute -prevent or contain new and re-emerging diseases
  • 49. References
    “Global Trends in Emerging Infectious Diseases,” February 2008 in the journal Nature.
  • 50. SGD questions