Zoonotic Flashcards
t/f : zoonotic microbes are culturable
false , they are non-culturable
Define the following
Zoonotic infections : An animal infection which is transmissible and pathogenic to human
Vectors : Organisms that do not cause the disease but spread the infection by conveying pathogens from one host to another
Reservoir host : The host of an infection in which the which the infectious host develop and is essential for the maintenance of the infection during times when active transmission to humans is not occurring in addition , reservoir host differ for each infectious agent and some share the RH and there are different RH for the same infectious agent
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Modes of zoonoses transmission
infecting humans via
- contact with diseased animal or animal bit eg rabbis and Ebola
- ingestion of contaminated food and water
- inhalation of infectious organisms
- through bite of a vector eg tick bite fever
they may also spread from one person to another
- contact ,ingestion , inhalation ,vector
- blood or stem cell transfusions , organs and tissue transplantation
Differentiate between the rickettsia diseases tick bite fever
*Types
African Tick Bite
agent: Rickettsia africae
mode of transmission :Mode of transmission: bite of the tick that fed on infected wild animals
Epidemiology: Sub-saharan Africa, West Indies
Organs affected: Skin ( eschar, rash). All other organs can be affected as a complication
Mediterranean Tick Bite Fever
*Causative agent: Rickettsiae conorii
*Mode of transmission: bite of the tick that fed on infected animals
Epidemiology: Mediterranean basin, South Africa, India, Israel
Organs affected: Skin (eschar, rash)
More likely to develop complications than ATBF. Then, other organs can be affected
Discuss the typhus pathogenesis
Causative agent : Rickettsiase Prowazekii ( human lice )
Rickettsiae typhi ( mouse / rat fleas)
*Mode of transmission : bite of louse or flees that feed on rats or mice
Epideiology : central east africa , south africa
Organs affected: Skin ( rash)
Risk of complications :
Louse borne > Mouse borne. Then, other organs can be affected
Discuss the infections caused by bartonella spp that are not zoonotic
- Carrions disease ( he most common findings are fever (usually sustained, but with temperature no greater than 102 °F (39 °C)), pale appearance, malaise, painless liver enlargement, jaundice, enlarged lymph nodes, and enlarged spleen. This phase is characterized by severe hemolytic anemia and transient immunosuppression. )caused by bartonella bacilliforms and trench fever (onset of trench fever is sudden, with fever, weakness, dizziness, headache (with pain behind the eyes), conjunctival injection, and severe back and leg (shin) pains. Fever may reach 40.5° C and persist for 5 to 6 days.) caused by Quintana and are seen in HIV patients
Discuss the infections caused by bartonella spp that are zoonotic
- Cat scratch disease caused by bartonella henselae
- Mode of transmission ;cat flees ( that feed in infected cats) excreta enter broken skin
- Epidemiology : worldwide
organs affected :
infect RBC and endothelial cells characterized by nodular proliferation on the skin .
with dissemination ,all organs can be affected
define bioterrorism and give the categories and examples
*Bioterrorism is the deliberate release in infectious agents used to cause illness or death in people , animals or plants
1 Category A *Easily disseminated or spread from person to person *Result in high motility rate *Has major public impact eg bacillius anthracis ( anthrax ) filoviruses (ebola)
- Catergory B
* moderately easily disseminate
* less lethal than category A
eg food safety threats
Brucella species
Coxiella burnetti- Q fever
chlamydophila psittaci ( psittacosis)
- Category C pathogens
*including emerging infectious diseases
*easily available / can disseminate / producible
*Major health impact , high mortality
eg HIV , SARS
Discuss the Q fever pathogenesis
Causative agent : Coxiella Burnetti
Epidemiology: World wide ( except New Zealand and Antarctica
MOT ; Infected animals shed during birth leads to environmental contamination
Humans aquire the infection through inhalation of infective aerosol
Stages of Q fever
*Acute Q fever ;
majority of infections are asymptomatic and some show flu like symptomes and may affect lunfs
*Chronic :
affects the heart
Psittacosis
causative agent : Chlamydophila psittaci
Epidemiology : World wide ,increasing in developed countries
MOT : infected psittacine birds discharge organisms from beaks , eyes, faces ,feathers become contaminated
- Humans inhale the infected aerosol
- Psittacosis occur mainly in the lungs and other organs get infected
Discuss the Francisella tularemia
- category A
2.Epideomiology : N America and canada , central asia - MOT: Ticks , horses, deer flies , mosquitos are vectors and small rodents / rabbits are HR .
Can be inhaled AND DIGESTED .
nor HUMAN TO HUMAN INFECTION
Organ affected : Depends on how it entered the skin
Discuss Brucella (brucellosis )
Category B
*Epi ; S America , Mediterain ,
Agent : 9 species
6 terrestrial and 3 marine eg B melitensis (goats , sheeps camels )and B arbortus (cattle and buffalos )
MOT ;Consumption of unpasteurised milk or its products, contact with infected animal parts or aerosolization of infective particles. Human-to- human transmission does occur
organs affected ; Like=Tb can affect any organs especially lungs and GIT
Questions to ask when suspecting zoonotic infection
1.Residence travel history occupation eg vet , farmer ,abattoir worker ect ingestion of potentially contaminated food/ water hobbies pets presence of skin lesions knowledge of local epidemiology
