<< Chapter < Page Chapter >> Page >

Contact transmission

Contact transmission includes direct contact or indirect contact. Person-to-person transmission is a form of direct contact transmission . Here the agent is transmitted by physical contact between two individuals ( [link] ) through actions such as touching, kissing, sexual intercourse, or droplet sprays . Direct contact can be categorized as vertical, horizontal, or droplet transmission. Vertical direct contact transmission occurs when pathogens are transmitted from mother to child during pregnancy, birth, or breastfeeding. Other kinds of direct contact transmission are called horizontal direct contact transmission . Often, contact between mucous membranes is required for entry of the pathogen into the new host, although skin-to-skin contact can lead to mucous membrane contact if the new host subsequently touches a mucous membrane. Contact transmission may also be site-specific; for example, some diseases can be transmitted by sexual contact but not by other forms of contact.

When an individual coughs or sneezes, small droplets of mucus that may contain pathogens are ejected. This leads to direct droplet transmission , which refers to droplet transmission of a pathogen to a new host over distances of one meter or less. A wide variety of diseases are transmitted by droplets, including influenza and many forms of pneumonia . Transmission over distances greater than one meter is called airborne transmission .

Indirect contact transmission involves inanimate objects called fomites that become contaminated by pathogens from an infected individual or reservoir ( [link] ). For example, an individual with the common cold may sneeze, causing droplets to land on a fomite such as a tablecloth or carpet, or the individual may wipe her nose and then transfer mucus to a fomite such as a doorknob or towel. Transmission occurs indirectly when a new susceptible host later touches the fomite and transfers the contaminated material to a susceptible portal of entry. Fomites can also include objects used in clinical settings that are not properly sterilized, such as syringes, needles, catheters, and surgical equipment. Pathogens transmitted indirectly via such fomites are a major cause of healthcare-associated infections (see Controlling Microbial Growth ).

Photo of person kissing a child and one of person playing arm wrestling with a child.
Direct contact transmission of pathogens can occur through physical contact. Many pathogens require contact with a mucous membrane to enter the body, but the host may transfer the pathogen from another point of contact (e.g., hand) to a mucous membrane (e.g., mouth or eye). (credit left: modification of work by Lisa Doehnert)
Photos of person touching doorknob, towel on a hook, and end of a syringe.
Fomites are nonliving objects that facilitate the indirect transmission of pathogens. Contaminated doorknobs, towels, and syringes are all common examples of fomites. (credit left: modification of work by Kate Ter Haar; credit middle: modification of work by Vernon Swanepoel; credit right: modification of work by “Zaldylmg”/Flickr)

Vehicle transmission

The term vehicle transmission refers to the transmission of pathogens through vehicles such as water, food, and air. Water contamination through poor sanitation methods leads to waterborne transmission of disease. Waterborne disease remains a serious problem in many regions throughout the world. The World Health Organization (WHO) estimates that contaminated drinking water is responsible for more than 500,000 deaths each year. World Health Organization. Fact sheet No. 391 —Drinking Water. June 2005. http://www.who.int/mediacentre/factsheets/fs391/en. Similarly, food contaminated through poor handling or storage can lead to foodborne transmission of disease ( [link] ).

Questions & Answers

what is bacteria
Ibrahim Reply
a member of a large group of unicellular microorganisms which have cell walls but lack organelles and on organised nucleus and ,including some which can cause disease
Nadiya
what is a germ
Ibrahim
a microorganisms,speciallay one which causes disease .
Nadiya
bacteria are a type of biological cells. They are unicellular. Bacteria were among the first life forms appear on the earth. they have a number of shapes, typically a few micrometers in length. They are present in of its habitata on earth.
isha
What is Auto clave?
Lovely
Autoclave is a pressure chamber used to sterilize equipments
praveen
hi
Lovely
n
vijaya
hii
chandi
what is a Laminar air flow?
isha
Laminar airflow cabinet is a carefully enclosed bench designed to prevent contamination of semiconductor wafers, biological samples or any particle sensitive materials
praveen
Praveen Deepi.... thnq....
isha
what bacteria causes malaria
Silas
female anaphilis mosquitos!
Nadiya
malaria isn`t caused by a bacteria rather by a digenetic parasite named Plasmodium.
Online
plasmodium sp
SRUTHI
its caused by a plasmodium germ....
Cotilda
Malariya cycle
Mohit
what caused the expansion of the wound
Blessing Reply
Robert Koch ka Pura naam kya h?
isha Reply
the theory of Koch,'s Postulation are: 1_Any disease must found microorganism 2_Microorganism can grow it outside pure culture 3_ Pure culture can inoculated to susceptible host and can cause typical disease. 4_ Microorganism can reisolated from inoculated disease from susceptible host.
Algur
ok
Kwame
that good
Ifeoma
please I want a detailed explanation to " G6PD result being Partial Defect" of a young lady.
Kwame
a.o.a can u please tell me five name of Gram +be bacteria
Tahira Reply
a.o.a...please send me five name of Gram +ve bacteria
Tahira
a.o.a...please send me five name of Gram +ve bacteria
Tahira
a.o.a...please send me five name of Gram +ve bacteria
Tahira
staphylococcus ,streptococcus,lactobacillus,mycobacterium,clostridium, bacillus,enterococcus.
Nadiya
thank u so much
Tahira
1. Staphylococci 2. Mycobacterium tuberculosis 3. Bacillus anthrasis 4. Chlostridium 5. Diplococci
praveen
gram -ve mn knsy hn
Tahira
pseudomonas
Nadiya
wo bhi 5 hon
Tahira
salmonella,proteus,shigella,neisseria
Nadiya
wo bhi 5 hon
Tahira
Nadiya ap kia krti hn?
Tahira
bsc microbiology final year
Nadiya
1. Neisseria gonohorreae 2. E.coli 3. Salmonella typhi 4. Klebsiella pneumonia 5. Shigella dysenteriae
praveen
1. Neisseria gonohorreae 2. E.coli 3. Salmonella typhi 4. Klebsiella pneumonia 5. Shigella dysenteriae
praveen
1. Neisseria gonohorreae 2. E.coli 3. Salmonella typhi 4. Klebsiella pneumonia 5. Shigella dysenteriae
praveen
MSc zoolgy. 1st semester
Tahira
B.Sc microbiology 1st year
praveen
good
Tahira
mn vu sy hoon and u?
Tahira
davv
Nadiya
Vijaya College,R.V.Road,Basavangudi Bangalore-560004
praveen
oh!! bht khub
Nadiya
hi
Nouman
how are u
Nouman
thank u friend
Nouman
please define classification of bacteria
Nouman
calssification of bacteria are of 3 types: ●.on the basis of shap:1.spirilla 2.bacilli 3.cocci ●in the basis of gram stain : 1.gram -ve 2.gram +ve ●on the basis of oxygen demand: 1.aerobic 2.anaerobic.
Nadiya
detail se please
Nouman
paresention hai iseley
Nouman
jo bacteria hote hai pehle to woh 3 tarha se unka classification kiya jata hai .pehle y ki shape kya hai ....lakin shape hum tab hi define kar payenge jab hum unhe pehchanenge ki bacteria ko kaise jane ki woh kaise hote hai or unka classification kaise hota hai
Nadiya
to hum gram staining karte hai
Nadiya
gram staining ek aaisi technique hoti hai jise hun 2 large group m devide karte hai
Nadiya
or differenciate karte hai bacteria ko
Nadiya
based on thir diff. cell wall constituents
Nadiya
gram staining ko 2 procedure mai distinguish between kiya gaya hai
Nadiya
gram positive and gram negative
Nadiya
phir
Nouman
gram +ve and gram -ve groups by colouring these cells red or violet colour.
Nadiya
red jo cells hogi woh pink bhi ho sakti h because stains ki wajah se uski quantity ki wajah se
Nadiya
gram positive bact.stain violet due to presence a thick layer of a peptidoglycon in theri cell walls are stained with.. or gram -ve bact.stain red .which is attribute to a thinner peptidoglycan wall.
Nadiya
ab hum unhe identify karenge microscope mai
Nadiya
then fir hum identify karte karte hum shape dekhenge
Nadiya
gram positive cocci or rod shaped k honge .or garm negative cocci or rods or spirochaetes honge .......lakin inke colour ki wajah se hum pehchanenge ki red or pink aaya to gram negative .or agar violet aaya to positive
Nadiya
ok?
Nadiya
fir
Nouman
or bhi types k hote hai bacteria jaise sphirical "cocci",rod "bacilli",spiral"spirilla",comma shape k jo honge woh"vibrio",or corkscrew shape k jo honge woh "spirochaetes.
Nadiya
fir
Nouman
or oxygen k basis pr dekhenge agar apan to woh :aerobic jo o2 ki presence m honge or anaerobic jo honge woh without oxygen ki presence mai servive karenge .sabhi micro organisms banate h energy cellular respiration k through. lakin aerobic and anaerobic k basis pr bhi diffrenciate hote hai yeh .
Nadiya
Streptococcus Staphylococcus Corynebacterium Clostridium
Srinivas
yeh 3no calssification batadiye detail mai ab aap net p or seach kar le
Nadiya
fir
Nouman
ok thank u so much
Nouman
کتنے پیارے اور چھوٹے سے خواب ہیں آپ کے ۔ الله پاک آپ کے سپنے سچ اور پورے کرے ۔ آمین ۔۔۔۔۔۔۔۔۔۔۔💝
Nouman
my pleasure!
Nadiya
acha ji ap ho kaha se
Nouman
Hyderabad
Srinivas
telangana
Srinivas
Can hiv virus survive in mosquitoes?
Mad
hiv virus cannot survive in mosquitoes.
Nadiya
Lol
Number
What,s the correct answer?
Nadiya
:-)
Nadiya
We will also know?what's the right answer !
Nadiya
Good going people
Number
Ok tell me all the conditions where a gram positive organism appears wrongly as gram negative organism in microscopy
Number
Staphylococcus Listria 2.Streptomyces 3. Streptococcus 4. Clostridium 5. Propionibacteriu
Basem
We know answer!
Lovely
ok
Basem
but you tell me first :can hiv virus survivr in mosquitoes? i dont know what's the correct answer !
Nadiya
No it can't.... Coz retroviruses require CDt4 receptors for replication which aren't found in mosquitoes
Number
Samjhi?
Number
yaaaa .......jazakallah !
Nadiya
well done doc.!
Nadiya
Good
Number
scale up fermentation ? define plz !
Nadiya
U can find all these answers easily on Web. Discuss something which is unique
Number
what is the gram negative
Xaviery Reply
what is enzyme immobilizatio ?
Nadiya Reply
the process of decreasing the rate of enzyme activity.
Edward
shukriya edward knevy .thnks .
Nadiya
sorry thi one is about enzyme inhibition
Edward
enzyme immobization is imprisonment of enzyme in a matrix.
Edward
i am confused
Nadiya
about what
Edward
ok .....i understood ur last one msg .
Nadiya
thanks .
Nadiya
Hallow
Chimo
my pleasure
Edward
can you helpe me please 🤗🤗
Chimo
?
Nadiya
but why
Nadiya
imuhhe patta nhi aapka ki aap kon ho to mai kaise no. send karu aapko or kyu karu ? wajaah to bataaa .
Nadiya
mujhe pata nhi
Nadiya
I want to learn microbiology
rakesh
this app is very benifit to learn microbiology .
Nadiya
Man Topics for Microbiology
rakesh
Please tell me
rakesh
first.u clear ur basic concept in microbiology .
Nadiya
Secondly what should you do
Nancy
u can start ur studies in book by dubey and maheshwari author.
Nadiya
what is primary and secondary screening ?
Nadiya Reply
which scope in the field of dmlt corse ? snd plz explain your experiences with me !
Nadiya
Country?
Number
india
Nadiya
Depends on place
Number
your birth place ?
Nadiya
whats your profession ?
Nadiya
scope of microbiolgy?
Nadiya
Clinical microbiologist
Number
M a doctor
Number
Dmlt isn't that good in india
Number
Bakwas hai
Number
but why ?
Nadiya
whats ur counter plz give m answer ?
Nadiya
Coz i know
Number
Saturation
Number
oh .i get it.
Nadiya
but what choose i ?in this field?
Nadiya
Hmm
Number
Wats ur basic qualification
Number
Good evening all
Ngozi
microbiology
Nadiya
evening
Dennis
good evening 2 u
Nadiya
What microbiology?
Number
bsc final year in micro.......
Nadiya
Do msc n PhD then.... Its better than dmlt n ll
Number
but i dont do this
Nadiya
what Cadillac
Topcy
number@......u r a doctor ?
Nadiya
really
Nadiya
plz explain the defination of scale up of fermentation ?
Nadiya
how do micro biology aids pharmacy
Dennis Reply
please check Google.
Nadiya
bcz very interested topic are able in goggle site
Nadiya
I'm Jeremiah what are the step that involved Gram staining
Jeremiah Reply
place slide with heat fixed smear on staining
Nadiya
smear with crystal violet and let stand for 1 min
Nadiya
and then after 1 min gently wash rinse with tap water...than smear the grams idone and stand for 1 min
Nadiya
again rinse with tap water.then,rhe smear will appear as a purple circle on the slide
Nadiya
then ,decolarize 95%with ethyl alcohol and acetone .till the slide slightly and apply tge alcohol deop by drop for 5 to 10 sec.
Nadiya
and then the alcohol until runs the almost clear .carefully not to over decolorization
Nadiya
immideatly rinse with water.
Nadiya
view the smear using a light microscope under oil immersion
Nadiya
and then complete 😊
Nadiya
.
Nadiya
what is the relation between aspergillus and vinegar.
Asad
can anyone send me the procedure of using autoclave.
Asad
yeh i will....but i can send a site on google !then u can read easily and understand it the procedure of autoclave ? ok .
Nadiya
***google autoclave procedure.
Nadiya
and u write in google site ......procedure of using an autoclave
Nadiya
can anyone send me the calculation and formula for spread plate technique cfu/ml
Ankita
@Nadiya... I think u have missed the last step of gram staining after decolonization with alcohol we have to counter stain it with either basic fucshin Or Saffranin.
Ankita
yaa ofcourse ...thank u so much ankitaa.
Nadiya
hi asghar
Nadiya
who are u ? and where are u live from ?
Nadiya
Ideally we should use 5 second technique while making one slide of Grams stain
Number
what is scale up of fermentation ?
Nadiya
the most commonly used microorganisms in alcohol fermentation is?
Shaikh Reply
Saccharomyces cerevisiae
Online
saccharomyses
Nadiya
Yeast is the most commonly used microorganism for ethanol productionby fermentation. ... Besides S. cerevisiae, other examples of yeastsused for ethanol production are Schizosaccharomyces pombe, Kluyveromyces lactis, Candida spp., Pichia spp that are able to ferment...
bazi
Ethanol fermentation using the hydrolysate obtained after the saccharification of biomass is the last step in lignocellulosic bioethanol production process. The hydrolysate contains large amount of fermentable sugars that can be directly used by the ethanologenic microorganisms. Yeast is the most co
Najeebul
saccharomyces
Nadiya
yeast
Nadiya
yeast
Veronica
A.o.a aspergillus aur vinegar ka kia relation he.?
Asad
Hmm
Number
what is difference between primary host and secondary host ?
Edward
what is primary screening and secondary screening ....hmm?
Nadiya
primary and secondry host ...best example of female anaPhilis .and disease -maleria !
Nadiya
i am asking about difference not example
Edward
Primary host- the host in which the adult parasite lives, and reproduces sexually. Secondary host- the host in which the immature forms of parasite lives
bazi
primary host -the host in which the adult parasite lives ,and reproduces sexually.and the second host -host in which the immature forms of parasite lives. okyyyy?
Nadiya
synthesis of DNA from a single strand of RNA
Veronica Reply
In this initially , a single stranded RNA is taken into a eppendorff tube as a template for synthesis of Double stranded DNA and dNTPs are added along with reverse transcriptase enzyme . All should be placed in buffered solution. Then above mixture is run on RTPCR machine.
Ravikumar
In which initially double stranded RNA- DNA hybrid is formed and later multiple copies of Double stranded DNA is Formed in number of cycles.
Ravikumar
exactly
Nadiya
what is a virus?
abdulwali Reply
What is DNA transcription
abdulwali
virus is not a bacteria ...it is present in our body fluid .the protein are not composed and work in a proper manner the virus present quikly .
Nadiya
i refer a book name .u find ur question answers .12 or 11th book
Nadiya
DNA trancription is a process the imfirmation are transfer into dna to dna and dna to rna is called dna transcription
Nadiya
in other words,dna transcription ,:in thich a particular segment of dna is copied into rnaand especially mRNA by the enzyme rna polymerase .
Nadiya
why most virus are of RNA genome?
Mika Reply
Good Question❓
MALESELA
its due to their fastidious nature.
Kwame
enlist types of bacteria on tha basis of arrangement of tha flagella
Mihir Reply
monotrichous:vibrio cholerae, amphitrichous,lophotrichous,and last peritrichous.
Nadiya
econom emportance of bacteria
Japhet Reply
We can get agar which is used in microbiological media
Kashif
cause disease
Mika
industrial use.
Nadiya

Get the best Microbiology course in your pocket!





Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Microbiology' conversation and receive update notifications?

Ask