zoonotic diseases: ebola in africa
DESCRIPTION
This presentation was my Senior Biology Major Capstone and was given along with a written paper. The presentation discusses three scientific papers following the ebola virus from fruit bats to carriers such as gorillas, chimpanzees, and humans.TRANSCRIPT
Zoonotic Disease Transmission : Ebolavirus in Africa
Antoinette RiveraBaldwin-Wallace College
Senior SeminarJanuary 22, 2010
Zoonotic Disease: Cross species transmission of an infection.
▫Endemic: usual rate of disease within a certain area.
▫Epidemic: unusually high rate of disease within a certain area.
▫Host, Carrier: Animal, insect or plant that carries the infection (viral, bacterial, parasitic).
▫Vector: Any living thing that humans receive a disease from.
▫Reservoir: Animal that carries the infection that occurs naturally but is not affected by it.
Places Zoonotic Diseases affect (1940-2004)Global trends in emerging infectious diseases
Kate E. Jones, Nikkita G. Patel, Marc A. Levy, Adam Storeygard, Deborah Balk, John L. Gittleman & Peter Daszak
Blame Apportioning and the Emergence of Zoonoses over the Last 25 YearsS. B. Ca’ceres and M. J. Otte
Ebolavirus (EBOV) Classification
Family Filoviridae
Genus Filovirus
Species Marburg &
Ebola
Ebola Subspecies-
Zaire, Sudan,
Bundibugyo, Reston,
Ivory
Filovirus Virus Structure
•Branch with folded Nucleocapsid containing the RNA. •Negative-Sense ssRNA, 19,000 RNA bases.
• Humans: 3 billion (3 x 109) base pairs in DNA.
•Encodes for ~7 proteins.
Filovirus- Ebola
http://phene.cpmc.columbia.edu
Branch
Branch
Nucleocapsi
d
Nucleocapsi
d
Ebola Infection
•Direct contact with:
▫Infected blood, organs, tissues and other secretions
▫Handling of infected wildlife
▫Plants
Ebola Attack on immune system
Primar
y
•Mucosal Epithelium
•Skin: Cut, Abrasion
Secondary
•Lung
•Liver
•Spleen
Targeted
Cells
•Dendritic Cells
•Macrophage
•Endothelial
Hemorrhagic Fever• Incubation: 1st week
▫Fever▫Weakness▫Muscle pain▫Headache▫Sore throat▫Vomiting▫Diarrhea
• Late symptoms: 2nd-3rd weeks▫Bleeding (eyes, ears, nose, mouth, rectum)▫Eye Inflammation▫Genital Swelling▫Rash over entire body (hemorrhagic)▫Seizures▫Coma
Mortality rate: ~50-90%
Vaccine/Cure
How Ebola and Marburg viruses battle the immune system. Mansour Mohamadzadeh, Lieping Chen, and Alan L. Schmaljohn*
http://www.nsrc.org/AFRICA
Major Ebola
Outbreaks
Ebola in Africa
Year Place # Cases # Dead Mortality Rate
1976 Sudan,Congo
284318
151280
53%88%
1994 Gabon 57 30 53%
1995 Democratic Republic of the Congo
315 250 79%
1996 Gabon 60 45 75%
2000 Uganda 425 224 53%
2001-2003 Gabon +Democratic Republic of the Congo
302 254 84%
Total Deaths up until 2003
1850 1200 65%
Africa and Ebola
Year Place # Cases # Dead Mortality Rate
1976 Sudan,Congo
284318
151280
53%88%
1994 Gabon 57 30 53%
1995 Democratic Republic of the Congo
315 250 79%
1996 Gabon 60 45 75%
2000 Uganda 425 224 53%
2001-2003 Gabon +Democratic Republic of the Congo
302 254 84%
Total Deaths up until 2003
1850 1200 65%
Africa and Ebola
1 person=10 people 185 People
EBOLA
1 person=10 people 65 People
Pathway for Transmission
Reservoir
Carriers
Humans
Potential Reservoirs
Mammal Other Vertebrate
Arthropod Plant?
Potential Mammalian Filovirus Reservoirs
A. Townsend Peterson, Darin S. Carroll, James N. Mills, and Karl M. Johnson
Which mammals?
•Reviewed all mammal species in the world.
•Deletions of genera based on 5 rationale criteria were made.
•Reviewed previous studies that tested African mammals for the virus.
Study Rationale1. Previous studies that suggest mammals.
2. Size.
3. Virus known to have a long-term evolutionary relationship with the reservoir species.
4. Range.
5. Non-commensal animals.
Families and Sub-families Fitting all rationale points
CrocidurinaePotamogalinaePteropodinaeMacroglossinaeEmballonuridaeMegadermatidaeRhinolophinaeHipposideridaeKerivoulinaeVespertilionidaeMiniopterinaeMolossidaeNycteridae
Procaviidae
SciurinaeMuridaeCricetomyinaeDendromurinaeGerbillinaeAnomaluridaeZenkerellinaeGraphiurinaeThryonomyidaeLeporidae
http://farm1.static.flickr.com
http://www.nwtrek.org/
http://thewebsiteofeverything.com
Bats seem to be focal point
•Of the 24 families and subfamilies of mammals, 11 are bats.
•Other studies have tested bats for antibodies to the virus; 3 fruit bat species were positive.
•Further research has a focus on probable species.
Pathway for Transmission
Host
Carriers
Reservoir
? ?
Humans
Apes As Carriers and Hosts of Ebola
•Apes are considered carriers and hosts because:
▫Infect other animals in the area.
▫Succumb to the disease (90-95% ape mortality).
▫Can be transmitted between ape species. (Gorillas, Chimpanzees, Humans)
Apes and Ebola
•Gabon and the Congo hold ~80% of the world’s great apes.
•Between 1983 and 2000 ape populations have declined by half due to hunting and Ebola.
•Deaths of gorillas, from Ebola, in the area of Gabon were tallied to be approximately 5000 individuals by 2000.
Gorillas and Chimpanzees
Western Lowland Gorilla (Gorilla gorilla gorilla)
http://www.cleverbadger.net http://www.apetag.orgg
Common Chimpanzee (Pan troglodytes)•Live in Cameroon, Equatorial
Guinea, Gabon, Republic of the Congo, DRC
•Eat pith, leaves, shoots and fruit
•Live in Cameroon, Congo, Gabon, Nigeria, and DRC
•Eat fruit, tree seeds, flowers, soft pith, galls, resin and bark
Potential for Ebola Transmission Between Gorilla and
Chimpanzee Social Groups
Peter D. Walsh, Thomas Breuer, Crickette Sanz, David Morgan, and Diane Doran-Sheehy
Is there potential for infection to pass between ape populations?
•Researchers used the fruit bat as an assumption, referencing previous study.
•Surveyed fruit trees.
•Analyzed feeding periods of both species.
Which fruit tree?•Apes are very picky about fruit.•Both apes leave bodily secretions on the fruit,
tree or surrounding (Urine, feces, saliva).•Types of trees: Nauclea pobeguinii (African
Peach), Ficus
http://www.ethnopharmacologia.org/
http://arbresvenerables.free.fr/ArbresVenerables
Findings: Gorilla-Gorilla Transmission
•15 total social groups (units) eating in 37 African Peach trees.▫4 Solitary silverbacks, 11 groups of 2+
•# of Cases:▫56: pair of units fed in same trees on the same
day, using same paths.▫13: gorilla(s) from one unit fed in the same tree
on the same day as another had.
Gorilla –Gorilla Foraging Overlap
Findings- Gorilla-Chimpanzee
•Observed 4 different communities of chimpanzees in Ficus.
•5 out of 75 days (once for every 15), Chimpanzees and Gorillas foraged in the same tree at the same time.*▫Lasted for ~47 minutes: ~10 Chimpanzees, ~4
Gorillas
*True Rates of occupancy might have been higher.
Pathway for Transmission
Host
Carriers
Reservoir
Chimpanzee
Humans
Human contact with non-human primates
Exposure to Nonhuman Primates in Rural CameroonNathan D. Wolfe, et. al. 2004
Habitat
Savanna
Gallery Forest
Forest
% R
ep
ort
ing
Beh
avi
or
Keep pet NHP
Butcher NHP
Hunt NHP
Eat NHP
Avg
. n
o. N
HP
Meals
per
mon
th
Cameroon
Gabon
Congo
Dem. Rep. of Congo
Uganda
Sudan
http://files.posterous.com/forestpolicy/
Wild Animal Mortality Monitoring and Human Ebola Outbreaks, Gabon and Republic of Congo,
2001-2003
Pierre Rouquet, Jean-Marc Froment, Magdalena Bermejo, Annelisa Kilbourn, William Karesh, Patricia Reed, Brice Kumulungui, Philippe Yaba, Andre Delicat, Pierre E. Rollin, and Eric M. Leroy.
Sampled Carcasses•August 2001- June 2003, 98 carcasses
( Gorillas, Chimpanzees, and Duikers)
•Found carcasses using field GPS locations and villager sightings.
•Liver, spleen, muscle, skin and bone samples.
•2 Peaks of animal death: Nov-Dec 2001, Dec 2002-Feb2003.
Lab tests on samples
Testing For Antigen (Viral Coat)
Viral RNA Visual Confirmation of Virus
Test Used ELISA PCR- DNA Amplification
Immunohistochem Staining & Microscopy
•If one test was positive, the carcass was labeled infected.
* 21 carcasses sampled, 14 tested positive.
Carcass peaks coincide with human outbreaks
• Nov• Dec
2001• Oct• May
2001-02
• Dec• Feb
2002-03
• Dec• Apr
2002-03
Human Outbreak
Carcass Peak
Carcass Peak
Human Outbreak
51 Carcasses
20 Carcasses
92 Cases 70 Dead
143 Cases
128 Dead
Pathway for Transmission
Host
Carriers
Reservoir
Chimpanzee
Carcasses
Ebola is a problem without a solution…•Complicated pathways.
•Research each level and inhibit transmission.
•Find an alternative means of food and income for native Africans.
•One strain of Ebola has been in the U.S. another could possibly come and infect thousands of Americans.
•Continue work on a vaccine as well as treatment for humans and apes.
Thank You!!!•Family•Friends•Sisters•Teachers
▫Dr. Barratt▫Dr. Melampy
•Zoo Influences▫D’Edra Thompson▫Terry Joyce▫Dr. Kristen Lukas
http://media.photobucket.com/
http://farm2.static.flickr.com/
Any Questions?
http://i30.photobucket.com
ReferencesCaceres, S B., and M J. Otte. "Blame Apportioning and the Emergence of Zoonoses over the Last
25 Years." Transboundary and Emerging Diseases 56 (2009): 375-79. Web. 22 Nov. 2009.Jones, Kate E., Nikkita G. Patel, Marc A. Levy, Adam Storeygard et al. "Global trends in emerging
infectious diseases." Nature 451 (2008): 990-94. Web. 22 Nov. 2009.Mohamadzadeh, Mansour, Lieping Chen, and Alan L. Schmaljohn. "How Ebola and Marburg
viruses battle the immune system." Nature 7 (2007): 556-67. Web. 22 Nov. 2009. Peterson, A. Townsend, Darin S. Carroll, James N. Mills, and Karl M. Johnson. "Potential
Mammalian Filovirus Reservoirs." Emerging Infectious Diseases 10.12 (2004): 2073-81. Web. 10 Dec. 2009.
Rouquet, Pierre, Jean-Marc Froment, Magdalena Bermejo, Annelisa Kilbourn et al. "Wild Animal Mortality Monitoring and Human Ebola Outbreaks, Gabon and Republic of Congo, 2001-2003." Emerging Infectious Diseases 11.2 (2005): 283-90. Web. 22 Nov. 2009.
Walsh, Peter D. "Catastrophic ape decline in western equatorial Africa." Nature 422 (2003): 611-14. Web. 22 Nov. 2009.
Walsh, Peter D., Thomas Breuer, Crickette Sanz, David Morgan et al. "Potential for Ebola Transmission between Gorilla and Chimpanzee Social Groups." The American Naturalist 169.5 (2007): 684-89. Web. 15 Dec. 2009.
Wolfe, Nathan D., A. Tassy Prosser, Jean K. Carr, Ubald Tamoufe et al. "Exposure to Nonhuan Primates in Rural Cameroon." Emerging Infectious Diseases 10.12 (2004): 2094-99. Web. 22 Dec. 2009.