EAGLE PASS, Texas — Dengue fever cases are increasing along the Texas-Mexico border, with infection rates in the Lone Star State reaching levels not seen in more than two decades. Mexico has also seen an increase in hospitalizations and deaths due to complications from the virus.
Despite the proximity of Mexico and Texas border cities, dengue virus infection rates vary widely. Mexico has significantly higher infection and mortality rates from mosquito-borne viruses.
Texas didn’t see its first locally acquired dengue case this year until November. A Cameron County resident who lives just a few miles from the Mexican border was infected with the disease in Brownsville, Texas, according to the Texas Department of State Health Services (TDSHS). According to a recent press release, TDSHS data shows that as of November 25, there have been 106 travel-related dengue cases, including one death reported in Texas. This is the highest annual number of infections in Texas since 2002.
The agency warned residents to take precautions to avoid mosquito bites within Texas and while traveling abroad to countries where dengue fever is endemic.
In the Mexican border states across from Texas, the virus has had an even more dire impact for some surprising reasons. This year alone, the mosquito-borne virus has killed 33 residents in Tamaulipas, a state on the Mexican border across the Rio Grande from Brownsville, McAllen and Laredo, according to a recent report released by state officials. It is said that it was stolen. Brownsville’s sister city, Matamoros, recorded a total of 340 cases in 2024. In Reynosa, a city bordering the Rio Grande from McAllen, 163 residents tested positive for dengue this year.
Thirty-three residents of Coahuila, a state on the Mexican border across the Rio Grande from Eagle Pass and Del Rio, Texas, have died from dengue complications this year, La Rancherita del Aire News reports. did. In Piedras Negras, one of the state’s busiest border crossing areas from Eagle Pass, health officials said 50 percent of all dengue tests came back positive.
In Piedras Negras state, health authorities are struggling to treat people suffering from the most serious complications of dengue fever due to a lack of blood and plasma needed to properly treat the virus. In 2024, nearly 5,000 dengue cases were confirmed across Coahuila, most of them in Saltillo, the border state capital.
The dengue virus is transmitted by infected mosquitoes, and about 25% of infected people develop symptoms, according to the Texas Department of State Health Services. After about 3 to 14 days, infected people may develop a fever, nausea, vomiting, rash, muscle pain, joint pain, bone pain, pain behind the eyes, and headache. Most people fully recover within two weeks. However, about 1 in 20 people with symptoms develops a severe infection that can be fatal if untreated.
Differences in infection rates among border residents along both sides of the Rio Grande may be due to differences in lifestyle, according to a scientific report. In 1999, the Centers for Disease Control, working with health officials on both sides of the border, documented the disparity in infection between Nuevo Laredo, Mexico and Laredo, Texas. The two cities, separated by a thin strip of the Rio Grande, had vastly different rates of infection, as we see today.
The organizations participating in the study noted that more positive infections were confirmed among residents of Nuevo Laredo, despite the presence of a larger vector (Aedes aegypti) in Laredo. The report’s conclusions showed that the use of extensive air conditioning in Laredo significantly reduced infections.
The study concluded that 82% of homes in Laredo have air conditioning, compared to 24% in Nuevo Laredo. In Laredo, more homes had intact screen doors and more distance between them. The study noted that Laredo has fewer residents per home than the Mexican border city of Nuevo Laredo. Ultimately, scientists found that climate had less of an impact on infection rates than pure economics. Residents of Mexico spent a lot of time outdoors and were unable to protect themselves from vectors at home.
Randy Clark is a 32-year veteran of the U.S. Border Patrol. Prior to his retirement, he served as Division Chief of Law Enforcement Operations, directing operations for nine Border Patrol stations within the Del Rio, Texas area. Follow him at X (formerly Twitter) @RandyClarkBBTX.
