Giardiasis can occasionally be encountered as an outbreak.
A giardia outbreak requires both of the following:
(1) >= 2 cases of giardiasis
(2) cases are linked to a common exposure
Requirements for an outbreak:
(1) contaminated source
(2) vulnerable population
(3) a suitable connection between the two
Contaminated sources have included:
(1) water (well, municipal water supply, stream, lake)
(2) another person (with person-to-person contact, as with small children, or through fomites)
(3) food, typically uncooked
Vulnerable population:
(1) household
(2) childcare facility
(3) other group (college, military, church, etc)
Prevention
(1) proper hand hygiene
(2) cleaning and disinfecting home environments and child care facilities
(3) monitoring water quality of private wells
(4) proper food preparation
(5) prompt diagnosis and source identification
