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Zoonotic & Emerging Infectious Diseases

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  1. Zoonotic & Emerging Infectious Diseases U Kentucky ACVPM Study 2007 Marc E. Mattix, DVM, MSS Diplomate, ACVP

  2. Today’s goals • ACVPM study focus • Public health perspective to emerging issues • Underlying factors • Strategies into the 21st century • Individual diseases as illustration • Encourage critical thinking

  3. Emerging Infectious Disease “...new, reemerging, or drug-resistant infections whose geographic range or incidence in humans has increased within the past two decades or whose incidence threatens to increase in the near future.” “A new disease or a new manifestation of an old disease”

  4. Emerging Infectious Diseases • There has been >60% increase in human death due to infectious disease in the US in the past 20 years • Most (>70%) are zoonotic agents • A few are [recent] species-jumping agents

  5. Reduced PH influence Depleted infrastructure Rampant urbanization Ecological manipulation Global transportation CNN effect Public reaction Expansion of human, reservoir and vector populations Changing human susceptibility Microbial adaptation Terrorism Factors

  6. Zoonotic Disease • Definition • Diseases caused by infectious agents transmitted from vertebrate animals to humans • Infectious agents maintained in animal “reservoir hosts” • Reservoir hosts often do not show signs of disease • Humans are accidental hosts • There are over 160 recognized zoonotic diseases • Types of zoonotic disease agents • Metazoan parasittes (“worms”) • Protozoa • Bacteria • Viruses • Fungus

  7. Zoonotic disease agents • Metazoan Parasites • Roundworms & hookworms • Trichosis • Protozoan • Cryptosporidiosis • Amoebic dysentery (“Montezuma’s Revenge”) • Bacteria • Brucellosis • Leptospirosis • Virus • West Nile Virus • Avian Influenza • Fungi • Ringworm (Dermatophytosis)

  8. Rabies Francisella tularensis Yersinia pestis DF-2 Afipia felis Pasteurella multocida Sporothrix schenckii Toxoplasma gondii Staphylococcus aureus Afipia felis Chlamydia psittaci Toxocara cati Toxascaris leonina Dipyllidium caninum Salmonella spp Campylobacter jejuni/coli Microsporum canis Capillaria aerophila Bartonella henselae Feline Zoonotic Diseases

  9. Raccoons • Rabies • Salmonellosis • Baylisascaris procyonis

  10. Direct contact with infected reservoir hosts Inhalation Bites Ingestion Indirect contact with infectious agents Contact with contaminated environment Airborne Contaminated food and water Bites of infected Arthropods (“Vectors”) Transmission

  11. Agents infectious to man & animals that survive free in the environment Soil Water Infectious agents that only affect people Cholera Smallpox Infectious agents that only affect animals Classical swine fever African Horse Sickness Rinderpest Non-zoonotic disease agents

  12. CDC’s response • Enhanced surveillance and outbreak response • Renewed support of basic and applied research • Strengthen public health infrastructure • Training and information programs

  13. State and local initiatives • Rebuild public health infrastructure • Increase reporting and surveillance capacity • All-Hazard use of bioterrorism funding • New partnerships & programs • Public awareness

  14. RESERVOIR ENVIRONMENT VECTOR AGENT Predictive Epidemiology Humans

  15. Spring 1999

  16. West Nile Virus • Agent • Group B Arbovirus, Family: Flaviviridae • Genus: Flavivirus JE Antigenic Complex • JE, St Louis virus, Kunjin, Murray Valley, etc. • Enveloped ssRNA virus (40-60 nm) • 1st occurrence in the Western Hemisphere: • Spring 1999 (NY)

  17. West Nile Virus • Epidemiology • Mosquito vector (43 sp) • Most efficient vector is Culex tarsalis • Migratory bird reservoir • Humans & horses incidental [deadend] hosts • Humans: • Average age: 69 years (36-81), #1 risk factor= >50 yrs old • Case fatality rate: 3-15% • Incubation: 3-14 days • Date of onset: July-October • Most infections asymptomatic • 20% develop “West Nile fever” • 1/150 develop meningoencephalitis ().67%)

  18. 4 documented cases (2002-3) • No illness in the infants • Benefits outweigh theoretical risks of WNV transmission via breastfeeding

  19. (EQUINE)

  20. 30 2001 25 2000 1999 20 Number of cases 15 10 5 0 7/7 8/4 9/1 9/29 10/27 11/24 12/23 Week ending Date of Symptom Onset, West Nile VirusUnited States, 1999-2001

  21. Risk reduction • Personal Protection • Clothing • Repellants • Screening • Dawn & dusk activities • Reduce mosquito populations • Habitat reduction • Insecticides • Adulticides • Larvacides

  22. Mosquito Habitat Elimination

  23. Brucellosis • DEFINITION: An infectious disease of the reproductive system of livestock caused by Brucella • B. abortus biovars 1-6,9; B. meletensis biovars 1-3; B. suis biovars 1-5; B. canis • Gram-negative, aerobic, nonmotile facultative intracellular • Worldwide distribution • Reservoirs: cattle, swine, goats & sheep • Infectious dose: 10-100 organisms • Transmission • Direct contact, aerolization, ingestion (raw dairy products) • Organisms shed in urine, semen, milk, uterine fluids, blood, placenta & aborted fetuses

  24. Brucella species Ovis: Sheep Rangifer: now B. suis biotype 4 Neotomae : Desert wood rat Maris (B. pinnipediae & B. cetaceae): Marine mammals

  25. Human disease • 2nd most common Critical Biological Agent • 1992-1999: 813 cases (Primarily INGESTION) • Acute or insidious onset • Fatigue, fever & night sweats • Anorexia, weight loss, headache, malaise, osteoarticular illness, orchitis & epididymitis • Valvular endocarditis (2%) • High morbidity, low mortality • Diagnosis • Serum tube agglutination • 2-mercaptoethanol • Culture, ELISA, PCR

  26. Abortion with rare systemic signs 3rd trimester Endometritis Placental retention Decreased milk yield Arthritis in chronic cases Orchitis/epididymitis Horses Suppurative draining bursitis Fistulous withers (supraspinous bursa) Poll evil (supra-atlantal bursa) Clinical Signs: Livestock

  27. Pathology Necrotizing placentitis Autolytic fetus Acute bronchopneumonia Meningoencephalitis Adult livestock Endometritis Orchitis Mastitis Lymphadenitis Culture: BSL-3 Phage typing Immunoflourescence PCR Diagnosis

  28. Diagnosis: Culture • Samples: • Placenta/aborted fetus • FEMALE: • Reproductive tract • Mammary gland • Lymph nodes: Supramammary, pharyngeal, lumbar, iliac • Spleen • MALE: • Lymph nodes: Superficial, inguinal, suprapharyngeal, lumbar, internal iliac • Milk • Blood: Bacteremia uncommon in chronic infections

  29. Diagnosis: Culture • Enriched Brucella media (high serum content) • Brucella media with Crystal Violet • 37º at 10% CO2 x 5 days • Colonies appear day 3-4 • 1-2 mm, convex and opaque • Purple colonies on Brucella-CV media

  30. Diagnosis • Serology: Livestock • Agglutination assays- serum, milk & semen • Card test • Plate agglutination • ELISA • CF • Fluorescence polarization • Rivanol precipitation

  31. Control and prevention • Reservoir control • CALFHOOD VACCINATION • TESTING OF ADULTS • SLAUGHTER OF REACTORS • TRACEBACK/ID SYSTEM • Public education

  32. Tularemia • Francisella tularensis • 4 subsp. (F.t. subsp tularensis & holarctica) • Aerobic gram-negative coccobacilli • CAT A Critical Biological Agent (CDC) • Features • Large number of transmission routes • Tremendous species susceptibility • >100 invertebrates, >150 vertebrate spp. • Wide array of clinical syndromes • Environmental Persistence • Soil, water, amoeba, invertebrates, rodents

  33. Vectors HARD TICKS Transstadial/transovarian Human transmission MT: Dermacenter variabilis BITING FLIES Chrysops Tabanus Mechanical transmission Infective for 14 days Direct contact Skinning infected animals Ingestion Infected tissues Water (esp. Microtus spp) Inhalation Transmission

  34. Clinical presentations • Ulceroglandular (75-85%) • Ulcer and regional lymphadenopathy • Glandular (5-10%) • Oculoglandular • Conjunctivitis, cervical lymphadenopathy • Typhoidal (5-15%) • Oropharyngeal (1-2%) • Intestinal • Pulmonary

  35. Diagnosis • History of exposure • Culture • CHAB-A @ 37o • Paired serology • ELISA, tube agglutination, • IgM MAT • Histopathology • Immunohistochemistry • FA • Multitarget RT-PCR

  36. Courtesy of LTC K Steele USAMRIID

  37. Martha’s Vineyard • Risk groups • Gardeners & Landscapers • 2000 • Pulmonic form in 11/15 cases • 2005 • Pulmonic form in 3/8 cases • Epidemiologic investigation • Initiated in 2004

  38. Kosovo • Nov 2001 – Feb 2002 • 715 human cases • Ages 16-44 • Oropharyngeal form • Rodent contamination of food & water

  39. Texas, 2002 3600 infected PDs shipped to 10 states & 7 countries Human Tularemia Facility animal handler 3-yr-old child in Spain Captive Prairie Dogs

  40. Plague • Yersinia pestis • Family Enterobacteriaceae • Gram-negative coccobacillus • Bipolar staining (1-2 x 0.5 µm) • Non-spore forming & nonmotile • Slow-growing on standard media • CAT A Critical Biological Agent (CDC) • Plague is a reportable disease • CDC & WHO