Zoonoses Flashcards
check on learning
Diseases and infections which are naturally transmitted between vertebrate animals and Humans (WHO)
zoonoses
in the late 1600s, this scientist invented the microscope, investigations of etiological agents soon followed
Leeuwenhoek
Encephalitis in dogs with rabies
Ringworm in humans and animals
Glanders and tetanus in horses and humans
Epidemic of urban plague
Conditions dating back for centuries
ringworm first described in late 1840’s when they learned that the cat was a reservoir of human Microsporum canis in 1902.
Mycotic Diseases
Tick-borne relapsing fever found to be caused by a spirochete in 1873
Bacillus anthracis first describe by Loch in 1877
By 1890, most bacterial zoonoses known to occur at that time had been described.
Bacterial Diseases
Rocky Mountain Spotted fever caused by Rickettsia rickettsii was first described in 1909
Most rickettsial agents were described by the 1930’s
Rickettsial Diseases
In 1798 Jenner reported protection from human smallpox conferred by innoculation of cowpox
By 1903, rabies was the first confirmed viral zoonoses
By the 1930’s Electron microscopy confirmed most initial reports of viral zoonoses
Viral Diseases
Most Cestodes were described by 1880, Nematodes by 1800’s and Trematodes by 1870’s and Filarial Nematodes by 1930’s.
Most zoonotic protozoa described between 1885-1915 while the plasmodia (related to malaria) of primates were described between 1930-1960.
Parasitic Diseases
single-celled parasites and their role in disease continue through to the present.
coccidia and Microsporidia and other related single-celled parasites
Any illness that results from the transmission of agents from an infected host to another susceptible host.
Communicable Disease
Any vertebrate or invertebrate that harbors an agent which can be primary, secondary or incidental in nature.
Host
A host in which an agent normally lives and multiplies and depends on for survival and transmission.
Reservoir
Entry and development of an agent in the host
Infection
A clinically apparent disease that results from infection.
Infectious Disease
this is the host that harbors the infectious agent and has either an apparent or an inapparent disease. Normally referred to as the Carrier
Infected Individual
this is a term also used to describe an infected individual
Healthy or asymptomatic
Convalescent
Transient or chronic
carrier
this is the period of time during which the infectious agent can be transmitted either directly of indirectly to a susceptible host.
Communicable period
this is the term used to describe the time period between initial contact with the infectious agent and the onset of clinical symptoms.
incubation period
this is the presence of an agent on the surface of the body or on an inanimate object such as drinking glass, bed or food.
Contamination
the first individual recognized as being infected with the disease.
Index Case
the first or primary case having the disease.
Proband or Propositus
when direct transmission takes place from the infected host to a susceptible host by direct contact or through contact with an inanimate object or a non-biological mechanical vector).
NO developmental changes or propagation of the organism occurs during the transmission
Direct Zoonoses
what type of classification is the following?
rabies, trichinosis and brucellosis
direct zoonoses
when the agent multiplies and develops (or both) in either an invertebrate host before transmission or to the vertebrate host after transmission.
Requires that a definite prepatent or incubation period take place before transmission.
metazoonoses
what type of classification is the following?
Lyme disease, Arboviruses (Arthropod borne)
metazoonoses
requires more than one vertebrate host but NO invertebrate host.
Cyclozoonoses
what type of classification is the following?
Human Taeniasis, Echinococcosis (Tapeworms)
Cyclozoonoses
transmission requires a non-animal development site or a reservoir such as food plants, soil or other organic material.
Saprozoonoses
what type of classification is the following?
larval migrans and mycotic diseases
Saprozoonoses
Detection of disease
Measurement of the extent of occurrence
Identify the needed interventions
Evaluate the impact of interventions
Disease Surveillance
All the above except evaluation of
intervention aspects
Disease Monitoring
this type of host is described as follows?
Definitive (primary)
Intermediate (secondary)
reservoir host
described as follows?
Asymptomatic (healthy or subclinical)
Convalescent (Incubationary)
Carrier Host
described as follows?
Sylvatic – wildlife
Domicilated – Rats and mice Area of infected maintenance hosts - called natural focus, nidus or niche.
Habitat of Host
unusual occurrence of disease exceeding the expected numbers
Epidemic
A cluster of cases that may or may not be an epidemic
Outbreak
A widespread occurrence of disease, usually globally distributed or on its way to that level
Pandemic
an occurence of disease that meets the expected numbers
endemic
indirect transmission due to exposure to a common vehicle such as food, air, water, mechanical means.
common source
Are secondary cases resulting from the exposure to a primary case which serve to extend the period of infectivity.
Propagation
is the inhibiting of the introduction of a disease causing agent into a specific area, or population or to an individual.
Prevention
the steps taken to reduce and maintain the disease or the transmission at a tolerable level.
Control
The elimination of a disease causing agent from a specific population or area.
Total Eradication vs Practical Eradication
Eradication
the only disease that’s been totally eradictated
smallpox
keep the agent in
Isolation
Keep the agent out
Quarantine
Benign such as leash laws or restrictions of movement of livestock; Drastic reduction or elimination.
Population control
Vaccination of a critical number to keep down epidemics
Herd immunity
what type of transmission is this?
Touch, bite, sexual, droplet
direct transmission
what type of transmission is this?
Vector-borne such as a tick, mosquito or flea or Vehicle-borne such as food, water, soil
indirect transmission
what type of transmission is this?
dissemination of the infectious agent by aerosols to a suitable port of entry.
airborne transmission
what is this type of airborne transmission?
may remain for a long period of time
suspension
what is this type of airborne transmission?
(<5u) easily drawn into alveoli
small particle
what is this type of airborne transmission?
result from evaporation of fluids or atomization
droplet nuclei
what is this type of airborne transmission?
which are particles which result from soil
dust
Direct or indirect transmission from an infected individual to a susceptible individual – various modes of interspecies spread of Zoonoses
Horizontal Transmission
Transmission of a disease from one generation to another such as from mother to baby in utero via colostrum. An important feature in many vector-borne diseases.
Vertical Transmission
the characteristics that increase or decrease the likelihood of exposure, subsequent infection and prognosis.
Risk Factors
what is this type of risk factor?
Age, gender, breed/race, religion etc.
Host
what is this type of risk factor?
geographic features of occurrence
Place
what is this type of risk factor?
Time of day, seasonal (vector feeding)
Time
what is this type of risk factor?
Time and place
Environmental Factors
