WASHINGTON (Reuters) - A nationwide recall of eggs linked to an outbreak of salmonella that has sickened hundreds of people in three U.S. states has been expanded and now covers 380 million eggs.

WASHINGTON (Reuters) - A nationwide recall of eggs linked to an outbreak of salmonella that has sickened hundreds of people in three U.S. states has been expanded and now covers 380 million eggs.

The eggs all came from a farm in Iowa linked to salmonella cases in California, Colorado and Minnesota over the last three months, the U.S. Food and Drug Administration (FDA) said.

Affected by the recall are eggs packaged under brand names Lucerne, Albertson, Mountain Dairy, Ralph's, Boomsma's, Sunshine, Hillandale, Trafficanda, Farm Fresh, Shoreland, Lund, Dutch Farms and Kemps.

Wright County Egg, of Galt, Iowa, expanded a nationwide recall to 380 million eggs on Wednesday from the initial recall of 228 million, the Egg Safety Center said.

Salmonella outbreaks nationwide have increased fourfold since May, sparking an investigation of the foodborne illness in 13 states, said the FDA. No deaths have been reported.

State and local officials were investigating salmonella cases in Arizona, California, Colorado, Connecticut, Massachusetts, Maryland, Minnesota, North Carolina, Nevada, Oregon, Pennsylvania, Tennessee and Texas, the FDA said.

The number of salmonella cases reported each week, normally around 50, zoomed to 200 a week since May, the FDA said. Preliminary investigations pointed to eggs from Wright County Egg as a potential source.

Some 266 cases of salmonella in California have been linked to the eggs, Los Angeles County officials said on Tuesday.

"There have been confirmed Salmonella enteritidis illnesses relating to the shell eggs and traceback investigations are ongoing," Wright County Egg said in a statement.

The company is part of DeCoster Farms, a family-run agribusiness that is a large egg producer. There was no answer to several calls on Wednesday to DeCoster offices in Clarion, Iowa.

The FDA said it was conducting an extensive investigation at the Iowa company, including sampling, a review of records and a search for potential sources of contamination, such as feed.

The egg producer said it was cooperating fully in the investigation and was diverting its eggs to a breaker for pasteurization to kill any harmful bacteria.

Salmonella can cause fever, diarrhea, vomiting and abdominal pain and even more serious illness or death.

The eggs are in cartons of six, 12 or 18 eggs and come from plants identified as P-1026, P-1413 or P-1946 and followed by a number from 136 to 225. The figures are stamped on the end of the carton.