Infection causing microbes travel from patient to person through:
(i) Air: Sneezing or coughing since little droplets are thrown which they reach another person
through air. Example, common Cole, pneumonia etc.
(ii) Water: contaminated water carries disease causing microbes which cause infection on its
usage. Example, diseases such as cholera.
(iii) Sexual contact: Diseases such as syphilis or AIDS are transmitted by sexual contact from one
person to the other.
(iv) Animals: These are intermediaries, called vectors, transmitting diseases from a patient to the
host. Example, mosquitoes (Female Anopheles mosquito) cause spread of malaria.

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