I have travelled all over Mexico. Many people especially in farm communities still have no running water...the river that supplies their irrigation is also where they wash their clothes and where their sewage drains to. It is indeed a problem very much connected to third world conditions.
It is one of the main reasons a person can travel to Mexico, avoid all water sources but for bottled water and still return home with dysentery; they ate a salad.
Please cite when the last time was that Canada had an outbreak of hepatitis A connected to California agriculture. Hell...the last time California had an outbreak connected to agriculture it was traced to Mexican strawberries.
On edit: IN fact the strawberry scare a few years back was BLAMED on California strawberries but the berries were in fact from Baha California which is in MEXICO:
California strawberry sales hurt by a hepatitis scare involving imported berries took seventh in the list of 1997's top 10 stories. It was the second year in a row that California growers lost sales after their product was wrongly associated with disease contamination. A replay of the previous year's $40 million debacle--when California strawberries were defamed as the source of an outbreak of cyclospora--was averted by a nationally broadcast press conference clarifying that the hepatitis was related only to strawberries from Baja California Eighth place was taken by the listing of the Pacific Coast steelhead for federal protection. The Santa Maria River population was granted endangered status, while listing of two other North Coast and Central Valley populations was deferred until Feb. 9 pending further information. The endangered listing requires removing barriers to migration, screening diversion points to protect hatchlings in the spring, prohibiting steelhead sport fishing, and providing more water to critical reaches of the river. The Supreme Court decision to uphold generic commodity advertising was voted ninth. In its 5-4 ruling in Glickman vs. Wileman Bros. & Elliot, the high court found that marketing orders imposed no restraint on the freedom of any producer to communicate any message to any audience, did not compel any person to engage in actual or symbolic speech, and that believing their money was not being well spent did not give objectors to the programs a valid First Amendment complaint. Since the decision, all related cases pending in the U.S. Ninth Circuit Court of Appeals have been resolved in favor of the marketing orders.
http://www.cfbf.com/agalert/1996-00/1998/aa-0107b.htm