1 / 51

Vectorborne Infectious Disease

Vectorborne Infectious Disease. Vector. A living organism, usually an insect or other arthropod, that can transmit a communicable disease agent to a susceptible host. Vectorborne Disease Outbreak (VBDO). The occurrence of two or more cases of a vectorborne disease Risk increases with:

ross-norris
Download Presentation

Vectorborne Infectious Disease

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Vectorborne Infectious Disease

  2. Vector • A living organism, usually an insect or other arthropod, that can transmit a communicable disease agent to a susceptible host.

  3. Vectorborne Disease Outbreak(VBDO) • The occurrence of two or more cases of a vectorborne disease • Risk increases with: • Improper handling of waste water • Inadequate drainage of rainwater • Improper management of solid waste

  4. Climate Sensitive Diseases • Vectorborne Diseases: • Malaria (Mosquito) • Dengue Fever (Mosquito) • Lyme Disease (Tick) • Rocky Mountain Spotted Fever (Tick) • Erlichiosis (Tick) • Other vectorborne viruses

  5. Vector Transmission • mechanical transmissionthe transfer of a pathogen from an infectious source to a susceptible host by a vector without any reproduction or developmental changes in the pathogen • biological transmissionthe transfer of a pathogen to a susceptible host by a vector, with the pathogen undergoing reproduction, developmental changes, or both in the vector

  6. Insects as Vectors • Man as Principal Host • anthropophilicspecies that usually feed on humans. "human loving“ • Ex. dengue, epidemic typhus, filariasis, malaria, relapsing fever, yellow fever (urban) • Man as Incidental Host • zoonosis diseases of animal transmissible to man • Ex. African sleeping sickness, Chaga’s disease, encephalitis, hemorrhagic fever, leishmaniasis, plague, tularemia, yellow fever (jungle)

  7. Orders of Insect Vectors • Anoplura (anopl = unarmed; ura = tail)the sucking lice, containing the human head and body lice. • Diptera (di = two; ptera = wings)the flies, gnats, midges, and mosquitoes. • Hemiptera (hemi = half; ptera = wings)the true bugs, including the conenose bugs (which transmit Chagas' disease) and the bed bugs. • Orthoptera (ortho = straight; ptera = wings)the cockroaches, crickets, grasshoppers, katydids, mantids, and walking sticks. • Siphonaptera (siphon = tube; aptera = wingless)the fleas. • Acari the ticks.

  8. Anoplura (sucking lice) • Pediculidae: includes the human head and body louse (Pediculus humanus and Pediculus capitis) • Pthiridae: contains the human pubic louse or crab louse (Pthirus pubis).

  9. Diptera (The Flies and Mosquitoes) • Culicidae: The mosquitoes • 3000 species worldwide, 150 in North America • Muscidae: the muscid flies • Contain the house fly and the tsetse fly • Simuliidae: the black flies • 1000 species worldwide • Pscyhodidae: sand flies • Ceratopogonidae: the biting midges • Tabanidae: the horse and deer flies • 3000 species worldwide

  10. Mosquitoes Aedes spp. vectors of dengue, yellow fever, LaCrosse encephalitis, filariasis, other viruses Culex and Culiseta spp. vectors of SLE, EEE, VEE, WEE, WNV, RVF, filariasis, Anopheles spp. vectors of malaria, filariasis, heartworm Mansonia spp. Vectors of filariasis, RVF, WNV, Sindbis, other viruses Ochlerotatus spp. WNV, JEE, other viruses

  11. West Nile Virus 1999

  12. West Nile Virus 2000

  13. West Nile Virus 2001

  14. West Nile Virus 2002

  15. West Nile Virus 2003

  16. West Nile Virus 2004

  17. West Nile Virus 2005

  18. West Nile Virus 2006

  19. WNV Human Cases 2006

  20. WNV Bird Cases 2006

  21. WNV Veterinary Cases 2006

  22. New Routes of Exposure

  23. Muscid Flies House fly (Musca spp.)- mechanical vector of filth diseases (ex. Salmonella, Cryptosporidium, E.coli, etc.) Tsetse fly (Glossina spp.)- biological vector of African Trypanosomiasis

  24. Black Flies Black flies (Simuliidae) are biting flies that serve as vectors for Onchocerciasis (River Blindness) Onchocerciasis is caused by Onchocerca volvulus, a parasitic worm that lives for up to 14 years in the human body

  25. Sand Flies Phlebotomine sand flies are vectors of various pathogenic agents responsible for diseases of animals including man : leishmaniases, bartonellosis and various arboviroses

  26. Leishmaniasis • Parasitic disease caused by obligate intracellular protozoa of the genus Leishmania spread by the bite of infected sand flies • Several different forms of leishmaniasis • cutaneous (cue-TAY-knee-us) leishmaniasis, which causes skin sores • visceral (VIS-er-al) leishmaniasis, which affects some of the internal organs of the body (for example, spleen, liver, bone marrow).

  27. Deer Flies Deer flies (Chrysops spp.) may serve as vectors for Tularemia and Loa Loa (loiasis)

  28. Hemiptera (true bugs) • Reduviidae - assassin and conenose or kissing bugs. About 2,500 species worldwide (subfamily Triatominae vectors Chaga’s Disease) • Cimicidae - bed bugs. At least 75 species worldwide.

  29. Chaga’s Disease • American Trypanosomiasis caused by Trypanosoma cruzi Acute: • Acute symptoms only occur in about 1% of cases. swelling of the eye on one side of the face, fatigue, fever, enlarged liver or spleen, and swollen lymph glands. Sometimes, a rash, loss of appetite, diarrhea, and vomiting occur. In infants and in very young children with acute Chagas disease, swelling of the brain can develop in acute Indeterminate: • Eight to 10 weeks after infection, the indeterminate stage begins. During this stage, people do not have symptoms. Chronic: • Ten to 20 years after infection, people may develop the most serious symptoms of Chagas disease. Cardiac problems, including an enlarged heart, altered heart rate or rhythm, heart failure, or cardiac arrest are symptoms of chronic disease. Chagas disease can also lead to enlargement of parts of the digestive tract, which result in severe constipation or problems with swallowing. Not everyone will develop the chronic symptoms of Chagas disease.

  30. Orthoptera (roaches) • Mechanical vectors • Several families • Most important include: • Periplaneta (American cockroach) • Blatella(German and Oriental cockroaches)

  31. Siphonaptera (the fleas) • Ceratophyllidae - mainly associated with rodents • Leptopsyllidae • Pulicidae - several species of human pests • Tungidae - chigoe fleas

  32. Plague • Yersinia pestis • Two forms: • Bubonic • Pneumonic • Transmission from Rodents via flea

  33. Acari (the mites and ticks) • Ixoididae • Ixodes and Dermacentor (hard ticks) • Argasidae • Orithodoros (soft ticks)

  34. Lyme’s Disease • Borrelia burgdorferi • red, slowly expanding rash (called erythema migrans or EM) • Neurologic and muscular symptomology, arthritis • Named after cluster of cases in Lyme, CT in 1970’s • First observed in early 20th century

  35. Rocky Mountain Spotted Fever • Rickettsia rickettsii • Clinical description • A tickborne febrile illness most commonly characterized by acute onset and usually accompanied by myalgia, headache, and petechial rash (on the palms and soles in two thirds of the cases).

  36. Vertebrate Vectors • Dogs • Cats • Raccoons • Bats • Mice • Etc.

  37. Rabies • Rhabdoviridae-nonsegmented, negative-stranded RNA genomes • Illness is acute encephalitis in all warm-blooded hosts, including humans, and the outcome is almost always fatal

  38. 0 Cases 1-4 Cases 5-9 Cases >=10 Cases Hantavirus Pulmonary Syndrome Cases by State of Exposure United States – September 19, 2006 Total Cases (N=453 in 30 States) Twenty-seven cases were reported with unknown state of exposure.

  39. Characteristics of Hantaviruses • No arthropod vector established • Unique among genera of Bunyaviridae • Rodent hosts • Genus and possibly species specific • Transmission • Aerosolization of rodent excreta

  40. Transmission of Hantaviruses Chronically infected rodent Horizontal transmission of infection by intraspecific aggressive behavior Virus also present in throat swab and feces Virus is present in aerosolized excreta, particularly urine Secondary aerosols, mucous membrane contact, and skin breaches are also sources of infection

  41. Peromyscus maniculatus Deer mouse Sigmodon hispidus Cotton rat

  42. Sin Nombre Virus Characteristics Bunyaviridae vertebrate hosts, no arthropod vectors spherical, 80-120 nm Glycoproteins: G1, G2 nucleoprotein: N ss-RNA, trisegmented, negative polarity Family Transmission Viral particles Structural proteins Genome

  43. Rodent Exposure 70 confirmed HPS cases Peridomestic exposure Peridomestic & occupational exposure Peridomestic & recreational exposure Occupational exposure Entering/cleaning rodent-infested structures 69% (48/70) 19% (13/70) 9% (6/70) 4% (3/70) 9% (6/70) Armstrong, L.R. et al., JID 1995; 172 (October)

  44. Prevalence of SNV IgG Antibodies in Select U.S. Populations Risk group Forest workers1 Health care workers2 Prodromal HPS3 Contacts4 Rural OCC5 Rodent workers6 Total Location/time SW US, 1993 SW US, 1993 SW US, 1993 SW US, 1993 SW US, 1994 US, 1994 Postive/tested (%) 0/143 0/396 3/299 (1.0%) 3/239 (1.3%) 1/522 (0.2%) 8/932 (0.9%) 15/2531 (0.6%) 2. Vitek et al, 1996 3. Simonsen et al, 1995 1. Vitek et al, 1996 4. Zeitz et al, 1995 5. Zeitz et al, 1995 6. Armstrong et al, 1995

More Related