By Barbara Tone, RN
March 6, 2000
Photo: Photodisc

Southern Texas is home to gorgeous coastlines and beautiful countryside. But it also is home to diseases that are rare or nonexistent in other parts of the country. Because of poverty and population issues along the border, differences in public health emphases, and difficulties with binational coordination, health officials often encounter problems not seen in inland areas.

"There are a number of different challenges," said Marty Cetron, MD, acting deputy director for the division of quarantine at the national Centers for Disease Control and Prevention. "Some regions lack sufficient infrastructure for sound public health, even in terms of things as simple as a good potable water supply or adequate sanitation and sewage systems."

Dengue outbreak

Hepatitis, TB, diarrhea, and infectious diseases are ongoing public health concerns in border areas. In addition, health officials on both sides of the border are on constant alert for outbreaks of diseases most U. S. practitioners will never see.

The Texas Department of Health (TDH) reports that the fall of 1999 brought the worst dengue fever outbreak since 1995. Southern Texas confirmed 60 cases, including one that resulted in the death of a girl. "It is spreading slowly, but it certainly appears to be here," said Julie Rawlings, MPH, epidemiologist with the infectious disease epidemiology and surveillance division of the TDH.

Dengue season runs from August to December. The disease is spread through a bite from an infected mosquito and is characterized by high fever and severe joint and muscle pain. It is usually not fatal but can be temporarily incapacitating. The southern Texas fatality was caused by a particularly severe case that resulted in dengue hemorrhagic fever, a variation that causes internal bleeding.

Health officials constantly caution healthcare practitioners to be on the lookout for unusual symptoms or clusters of the same symptoms among patients. Last fall’s outbreak likely would have been worse had it not been identified early. "An astute physician in Mexico called local health officials in Laredo to report that he was seeing a lot of what appeared to be dengue and requested a quick lab confirmation from our side of the border," Rawlings said.

When outbreaks are suspected, the health department circulates information to emergency departments and infection control divisions of local hospitals. Depending on the circumstances, TDH officials may go to the area and search emergency records for patients who may have had disease symptoms and attempt follow-up.

Vaccines and clean water

Much of the risk of dengue can be lessened by reducing or eliminating mosquito populations. "People can do so much to reduce the risk just by getting rid of containers or by changing the water in flowerpots, birdbaths, and kiddie pools," Rawlings said.

Southern Texas also has the dubious distinction of being the only place in the United States where the canine strain of rabies is found. Rabies vaccination programs were successful in eliminating the disease in the United States until 1988, when canine rabies was found in a coyote in Starr County. The disease spread, hitting a high of 142 cases in 1995. That same year, health officials began airdropping coyote bait containing a vaccine across southern Texas, and the number of cases dropped to eight last year.

While officials point out there have been no human cases reported since 1994, they stress the importance of taking protective measures. "We still strongly emphasize the importance of having animals vaccinated annually," said Doug McBride, public information officer for the TDH. "We don’t do the airdrops to make the life of the coyote better. It’s to protect people. It’s too easy for it to go from coyote to dog to person."

A coordinated plan

Officials on both sides of the border are working together to identify and control the diseases that have come with the large increase in border factories, the lack of public health infrastructure, and the difficulties of tracking diseases across international boundaries. The Border Infectious Diseases Surveillance (BIDS) program is one such effort.

A cooperative venture among a variety of public health entities in the United States and Mexico, BIDS has established nine border clinics in four sister cities with goals of enhanced data sharing, increased laboratory capacity, and improved surveillance for infectious diseases. "We are really pleased with the way the project was assembled with binational consensus," said the CDC’s Cetron.

"There is a gradual recognition that this border is almost like a country unto itself, in the sense that when you’re sharing a common border, you’re going to have common health situations," McBride said. "Viruses and bacteria don’t require a visa or passport."