MEXICO CITY (July 21, 2010)—Miguel Angel, the director of Mexico’s National Epidemiological Center, reports a spike in the number of hemorrhagic dengue fever cases in northeastern Mexico.

Angel said the disease's Type 2 strain is now in the Gulf coast state of Veracruz and moving north toward the U.S. border.

Type 1 is already present in such border states as Tamaulipas, which suffered extensive flooding in the weeks after Hurricane Alex made landfall June 30.

Lezana says Type 2 of the mosquito-borne illness makes those who have had Type 1 more vulnerable to developing the hemorrhagic form.

Cases of the milder, classic form have declined slightly in Mexico since 2009, but the more serious hemorrhagic form has spiked to about 1,900 cases this year, compared to about 1,430 in the same period of 2009.

Sixteen people have died in Mexico this year from the hemorrhagic form.