Routes of infection Flashcards
how many ways can a person be infected ?
5
what’s the 5 ways ?
person to person oral - food contaminated water vector fomites
within the person to person category there is 3 ways this can occur , what are they ?
direct contact
contaminated body fluids
vertical transmission
describe direct contact ?
Direct contact occurs when there is a physical contact between an infected person and a susceptible person
describe contaminated body fluids ?
this is when a person becomes infected by being exposed to contaminated blood e.g Ebola. Or body fluids such as STD’s. Also can occur due to saliva. An example of this can be when someone sneezes and releases contaminated droplets into the atmosphere.
describe vertical transmission ?
This is when a variety of pathogens are transmitted from a mother to her foetus.
give an example of how one infection can make you more susceptible to another another ?
Herpes simplex virus type-2 may increase a woman’s susceptibility to HIV-1, this is carried out below:
- initiation of a clinical or subclinical mucosal inflammatory response
- alteration of innate mucosal immunity
- weakening or breaching the protective genital epithelia
list 3 infections that can be vertically transmitted ?
septicemia
pneumonia
gram negative bacilli
describe oral transmission ?
Food can be contaminated with a variety of organisms such as parasites, bacteria and viruses.
when food has been infected can this be traced back to the source ?
it can be traced back to the source normally.
describe contaminated water ?
Oral ingestion or by bathing/swimming in contaminated water can lead to the transmission of infections.
what is the water normally contaminated with ?
faeces
in children if diarrhoea occurs what does this make them more vulnerable to ?
diseases and malnutrition
how is the schistosome transmitted?
by contaminated water and the water snail
what organism of the life cycle penetrates the host skin to transmit the infection ?
the cercaria
where do the cercaria come from ?
the infected snail
the adult worm releases eggs into the water , what do these go on to form ?
miracidia which contain cilia to help them swim to the snails to infect them
what occurs once the miracidia are within the intermediate host of the snail ?
they undergo development to complete it’s life cycle.
what are vector borne diseases?
infections transmitted by the bite of infected arthropod species, such as mosquitoes, ticks, triatomine bugs, sandflies, and blackflies, fleas.
what does an infected female mosquito infect the host with ?
malaria
what does an infected sandfly infect the human with ?
leishmania
what kind of pathogen is the leishmania ?
a protazoan parasite
why does the parasite have many different forms ?
it depends on the infecting host species and the hosts response
name some of the different types ?
mucocutaneous leishmania
visceral leishmania
what’s the 3 tick borne disease that can be transmitted via a tick ?
tick borne encephalitis
Lymes Borreliosis
Crimean Congo hemorrhagic fever ( CCHF).
describe tick borne encephalitis ?
arbovirus of the family Flaviviridae and is transmitted by ticks they act as both the vectors and resevoirs .
describe lympe borreliosis ?
infection with the bacterial spirochete Borrelia burgdorferi which is transmitted to human beings during the blood feeding of hard ticks of the genus Ixodes.
describe Crimean Congo Hemorrhagic Fever?
This is an RNA virus that is from the Bunyaviridae family. It has a fatality rate of 40% and is transmitted via the Hyalomma spp ticks from domestic and wild animals.
what is zoonosis ?
a disease which can be transmitted to humans from animals
what are fomites ?
This is when a form of indirect contact that causes transmission , it occurs from an object such as bedding , toys or towels , it has to be a contaminated surface
how is the flu virus and athletes foot contracted ?
by a fomite
what’s the most effective way of preventing an infection in people ?
by vaccination
how can the mouth and respiratory tract be infected ?
infected via inhalation or ingestion of the infective material for example saliva droplets.
give the pathogen and type of pathogen that can be transmiteed by mouth or respiratory tract ?
influenza viruses , pathogen is orthomyxovirus
how can the gastrointestinal tract become infected ?
by contaminated water or food
give the pathogen and pathogen type ?
rotavirus and disease is diarrhoea
how can the reproductive tract become infected ?
sexual transmission
pathogen type and diesease
Neisseria gonorrhoeae and the disease is gonorrhoea
is gnorrerhea gram positive or gram negative ?
gram negative
how are opportunistic pathogens transmitted and give an example ?
by resident microbiota and the pathogen is candida albicans and the disease is candidiasis thrush and the type of pathogen is fungus
how is the external surface infected and give an example ?
physical contact , the pathogen is trichophyton and the disease is athletes foot. The type of pathogen is a fungus
how are wounds and abrasions infected and give examples ?
by puncture wounds and the type of pathogen is a clostridium tetani which causes tetanus and the type of pathogen is a gram positive bacteria
how are insect bites transmitted and give example ?
transmitted by mosquito bites and the pathogen is flavivirus and the disease is yellow fever , the type of pathogen is a virus.
what are soluble mediators at the entry site?
anti infectives
defensins
complement
tissue residents cells at the entry site ?
epithelial cells
special type of macrophages such as alveolar macrophages
recruited cells that are innate ?
NK cells
neutrophils
recruited cells that are specific ?
B and T lymphocytes
antibodies
the whipworm trichuris thrichuria embeds in what and what does this result in ?
the epithelium of the colon which leaves the posterior free to the lumen
when infected what is the response ?
increased mucus production in the gut and this helps to overcome the pathogen
