Research sheds light on Valley dengue outbreak in 2005

Dengue fever

- Dengue fever is caused by a virus that is carried by certain mosquitoes. There is no vaccine and no cure.

- Symptoms of dengue infection include high fever, severe headaches, pain behind the eyes, joint and muscle pain and a rash. Most people recover fully.

- Dengue hemorrhagic fever is a complication of the disease and is more dangerous. Patients might show signs of shock, which can lead to death if left untreated.

- To prevent dengue, get rid of standing water in containers, or once a week rinse and scour containers that collect water. Install screens on doors and windows. When visiting areas with dengue, wear mosquito repellent and long-sleeve attire.

Source: U.S. Centers for Disease Control and Prevention

BROWNSVILLE — Cameron County was ground zero in the continental United States’ first outbreak of dengue hemorrhagic fever, according to research presented by health officials Wednesday.

Epidemiologists from the national Centers for Disease Control and Prevention and officials from the Texas Department of State Health Services have determined that in 2005 — during an outbreak of the dengue virus in Tamaulipas, Mexico — about 25 patients in Brownsville also were confirmed dengue cases.

Of those, nearly two-thirds had signs of dengue hemorrhagic fever, the more serious form of the disease, Allison Abell Banicki, epidemiologist for DSHS’ Office of Border Health, said.

Banicki and several health officials from Texas and Tamaulipas spoke at the South Texas-Mexico Dengue Prevention and Control Coalition’s planning meeting Wednesday in Brownsville.

People with previous exposure to dengue are at higher risk of developing hemorrhagic fever, and most of the U.S. cases involved people who had been previously exposed to the disease, Banicki said.

The findings add more puzzle pieces to the picture of what happened on both sides of the border during 2005’s dengue outbreak, in which Tamaulipas reported more than 1,000 cases of the disease and more than 200 cases of hemorrhagic fever.

The state of Tamaulipas, which has a broader definition of what constitutes a confirmed case, put the number of dengue cases even higher, at more than 4,000.

Usually, most dengue cases reported in the United States are “imported,” meaning the person contracted the disease from Mexico or another country, said Dr. Brian Smith, regional director for DSHS’ Region 11, which includes the Rio Grande Valley.

In 2005, however, the region saw its first cases of locally contracted dengue fever, according to a study published in August in the CDC’s Morbidity and Mortality Weekly Report. The study’s findings implied that dengue is growing beyond its usual borders, researchers said.

To keep future epidemics at bay, Texas and Mexico both need to educate their residents on dengue prevention and continue coordinating with each other, officials said.

Mexican health officials say they’re facing an uphill battle in stopping the spread of dengue in their country.

Conditions in much of Mexico — including poor sanitation, proliferation of used-tire dumping and the presence of trash in residents’ backyards — make it difficult to fully contain the disease, said Ernesto Lavin, preventive medicine coordinator for Tamaulipas’ secretary of health. The mosquitoes that carry the dengue virus flourish near standing water in tires and trash.

“We have to change the mentality (in Mexico),” Lavin said. “We’re trying to create a consciousness of the problem.”

The number of dengue cases in Tamaulipas has dropped significantly since the 2005 outbreak, however, with 143 cases in 2006 and 447 in 2007, according to Alfredo Rodriguez-Trujillo, state epidemiologist for Tamaulipas.

Only one dengue case was reported in Cameron County last year, said Laura Robinson, zoonosis control veterinarian for DSHS Region 11, in August. No confirmed cases of dengue have occurred in South Texas so far in 2007, epidemiologists said Wednesday.

Prevention is the key to stopping dengue, because the disease has no vaccine or treatment, Robinson said.

“It should be at the personal and community level,” she said.