Ch. 5 Ch. 5 Sec. 3 Sec. 3

Preventing Preventing Infectious DiseasesInfectious Diseases

immunityimmunitybody’s ability to body’s ability to destroy pathogens destroy pathogens before they can before they can cause diseasecause disease

2 kinds of immunity

1. active

2. passive

1. active immunity1. active immunity1.1. when person’s own immune when person’s own immune

system produces antibodies in system produces antibodies in response to presence of response to presence of pathogenpathogen

2.2. vaccination (immunization)vaccination (immunization) usually lasts for many years- usually lasts for many years-

sometimes for lifesometimes for life

vaccinationvaccination process by which harmless process by which harmless

antigens- deliberately introduced antigens- deliberately introduced into person’s body into person’s body creates creates active immunityactive immunity

given by injection, mouth, nasal given by injection, mouth, nasal sprayspray

Franklin D. Roosevelt in a wheelchairFranklin D. Roosevelt in a wheelchair

2. passive immunity2. passive immunity occurs when antibodies that occurs when antibodies that

fight pathogen come from fight pathogen come from another source rather than another source rather than from person’s own bodyfrom person’s own body

only lasts few monthsonly lasts few months

chemical that kills chemical that kills bacteria or slows bacteria or slows their growth their growth without harming without harming body cellsbody cells

does NOT work on does NOT work on virusesviruses

active active immunityimmunity

when person’s own when person’s own immune system immune system produces antibodies produces antibodies in response to in response to presence of pathogenpresence of pathogen

passive passive immunityimmunityoccurs when antibodies occurs when antibodies

that fight pathogen that fight pathogen come from another come from another source rather than from source rather than from person’s own bodyperson’s own body

passive passive immunityimmunity

•Only lasts few Only lasts few monthsmonths

active active immunityimmunity

•can last a lifetimecan last a lifetime

active active immunityimmunity

when person’s own when person’s own immune system immune system produces antibodies produces antibodies in response to in response to presence of pathogenpresence of pathogen

passive passive immunityimmunity

occurs when antibodies occurs when antibodies that fight pathogen that fight pathogen come from another come from another source rather than from source rather than from person’s own bodyperson’s own body

passive immunitypassive immunity

passive passive immunityimmunity

•only lasts few only lasts few monthsmonths