ddt 24 Flashcards
disease causing organisms are referred to as
pathogens
pathogens include:
- viruses
- bacteria
- prions
- protozoa
- metoza
misfiled proteins that can transmit its misfiled shape into normal variants of the same protein is
prions
single celled eukaryotes and are either free living or parasitic as trypanosoma brucei for sleeping sickness and trynososma Curzi for chagas disease are —
Protozoa
multicellular eukaryotes in biological kingdoms animi ad schistosomes - parastato flatworms
metoza
— are generally specialised for a particular method of transmission and the route of transmission is important to
epidemiologists as its shapes different responses and preventives measures
infectious agents
—- described the ability for an organism yo enter , survive , and multiply in a host
infectivity
—- of a disease agent indicates the cooperative ease with which its transmitted to another host
infectiousness
—- infectious agents passed from person to person or person to animals and all of — are infectious
contagious
— spread by an infectious agent but not from contact but from ——-
- infectious
1- airborne transmission
2- contact transmission ( direct or indirect )
3- vehicle transmission ( water, milk,food)
4- vector transmission
5- reans placental transmission
air borne transmissions is when a person w/ an infectious —- and the air will carry the infected droplet to healthy person and common symptoms are ——
sometimes while breathing we inhale dust particles that are infected
- cough , sneezes m breathes
- sine congestion , coughing , sore throat , inflammatory responses pf upper respiratory system
disease that are spread by air like
- cold n coughs
- influenza ( flu )
- measles , small box , chicken box
- whooping cough
- diphethia
- tuberculosis
- corona virus
Dirty hands are also responsible for carrying the germs of infectious diseases such as
Polio Myelitis.
— refers to the personal contact from direct physical contact w an infected person and is contagious .
—- contact with contaminated surface or substance as focal oral and is most common in hospital and families and sport contact
- direct transmission
- indirect transmission
vehicle-born transmission (inanimate objects) is included in
indirect transmission
Touching an infected person during a physical examination is —
direct transmission
direct and indirect transmission can lead to :
- ring worms
- small pox
- scabies
- impetigo
- scarlet fever
- covid 19
—- describes transmission of the disease agent through contaminated water, ice, milk, food, serum, plasma or other biological products (passively carry the pathogen) which provides an enviornemnt that supports the growth or toxins as: (e.g., botulinum toxin by Clostridium botulinum in improperly tinned foods.)
- vehicle transmission
— is most important vehicle of transmission in many areas of the world because it is used by every one - often ‘fecal-oral transmission’ or the ‘fecal-oral route’
water
water borne transmission includes:
- cholera
- typhoid fever
- viral hepatitis
- e coli
—- is an organism that does not cause the disease itself but that transmits infection by conveying pathogens from one host to another.
-vector
- For example, arthropods or other invertebrate hosts, which transmit infection by inoculation into the skin or mucosa by biting or by deposit of infective material on the skin or on food or other objects.
Vectors are often required in the life cycles of pathogens- common strategy is to interrupt this life cycle by killing the vector or controlling its behaviour.
vectors can transmit diseases by:
1- mechanical transmission which picks up the infectious agent outside of its body and transmits it in a passive manner as house fly , dust particles diseases may include: (b) Dysentery,
(c) Enteric fever,
(d) Diphtheria,
(e) Scarlet fever,
(g) Tuberculosis
2- biological vector transmission usually but not exclusive to arthropods as ticks , lice and mosiqtous and they have 3 types:
1- propagative: the disease agent multiplies and increases in insect vectors as: plague bacillus in rat flea
2- cyclo-propogative: the parasite undergoes a cycle of development in the body of the insect host with multiplication as malaria parasite plasmodium
3- cycle-development: the parasite undergoes a cycle of dvelopement without multiplication as: filarial parasite in culled mosquito and guiena worm nematode in embryo
plague bacilli is s a biological vector in —-
propagative
malaria parasite is —
cyclo-propagtaive
guinea worm is —-
cycle-developemtnal
trans placental transmission are diseases carried from
- infected mother to foetus in the uterus during childbirth ( perinatal infection ) or during child parent contact postnatally
as: Syphilis,
Rubella (German Measles),
Measles,
Toxoplasmosis
An infectious disease that is readily transmitted from person to person is considered a —
communicable disease these diseases can be transmitted from one person to another by direct ( as: physical contact , cough , sneeze ) or indirect methods ( intermediate mechanism as contaminated water or insect )
if a small number of cases are continually present in the population in a geographical area —
endemic
is the rapid spread of disease to a large number of hosts in a given population in a short period of time —
epidemic
( Sometimes endemic disease can flare up and assume epidemic proportions. This can happen when host immunity to either an established or new pathogen is suddenly reduced below that found in endemic equilibrium or if local conditions of transmission change (e.g. increased host vector populations or density).
— is a disease epidemic that has spread across a large region, for instance multiple continents, or worldwide
pandamic
true or false:
For a communicable disease to perpetuate itself there must be continuous transmission between individuals in the population (this can be by direct or indirect means
Thus in order to control or even eradicate the disease the chain of transmission must be broken.
true
effective control methods measures of any disease requires —- and — or else they won’t be effective.
- knowing the cause of the disease
- knowing the method of transmission
many diseases are controlled by —- once the life cycle of disease organism is known
- enviroemntal factors
eg:
Malaria - Mosquito control mechanisms
Cholera - Water sanitation
MRSA - Hand washing
HIV, Herpes - Condoms
COVID-19 - Social distancing, wearing face masks, hand washing - In addition to medical (e.g. respirators) and drug intervention we must include;
Education - water quality and safety
Environmental engineering - Sanitation facilities and design
Food - hygiene and quality, could also link to malnutrition and disease
Climate - could link to global warming- e.g., movement of vectors beyond current ranges.
Enhancement of the ‘Quality of life’ for humanity
not as important info ig
Miasma theory – ‘bad air’ – particles in air that arose from decomposing matter or dirty organic sources (Dr. William Farr, commissioner for the 1851 London Cenus and member of the General Register’s Office)
Germ theory – caused by a germ cell that had not yet been identified. (Louis Pasteur would not demonstrate this until 1861)
