Epidemic diseases may afflict large numbers of persons living in a particular geographical area. Symptoms of an epidemic disease also spread rather rapidly among many, but not all, persons in the same community. Epidemic diseases are frightening because of the number afflicted and because of the rapid spread of the disease. Some diseases, such as dengue fever and measles, disable victims for some days, but usually do not cause death. Others, such as cholera and yellow fever, cause a varying number of deaths. When particular groups have not been exposed to a disease vector, the outcome may be devastating, as appears to have been the case among the Plains Indians of Texas when they were exposed to the communicable diseases carried by the white settlers.
Texans experienced numerous epidemics during the nineteenth century. Cholera, yellow fever, smallpox, dengue fever, measles, influenza, diphtheria, and whooping cough afflicted Texans in different locales at different times. Though cholera appeared in 1833 and caused some deaths, it was far more destructive during an epidemic in 1849. Approximately 500 deaths from cholera had occurred in San Antonio by May of that year. During the early months of 1866 measles appeared "in nearly every house" in Galveston. In 1883 many residents of Galveston suffered with aches and pains of dengue fever. Galveston's doctors established a quarantine camp in 1899 to house some of the thirty-seven residents afflicted with smallpox.
Galvestonians experienced at least nine yellow fever epidemics between 1839 and 1867. The events of a yellow fever epidemic terrified everyone. A twenty-five-year-old man would be healthy one day and dead three days later, changing relentlessly from a state of debility, fever, and pains in the extremities and loins, to a stage of vomiting blood clots (called the black vomit), to jaundice and death. Doctors then did not understand the role of the mosquito in transmitting the yellow fever virus. Some thought that garbage heaps and stagnant ponds produced particles in the air (called miasmata) that caused the disease. To prevent their occurrence, doctors and town leaders advocated sanitary cleanups when epidemics appeared or threatened. Others believed that sick people transmitted the disease directly to others. During an epidemic in Galveston in 1839, Ashbel Smith tasted the "black vomit" of patients and did not become sick. He believed that yellow fever was not contagious and that Galvestonians should not quarantine incoming ships. Many disagreed with Smith and urged quarantines as ways to prevent the spread of this communicable disease.
Texans, like others, were confused because improved sanitation and enforced quarantine did not prevent epidemics from occurring or continuing. During a yellow fever epidemic in Galveston in 1853, approximately 60 percent of the 5,000 residents became sick and 523 persons died. There were 175 deaths from yellow fever in Houston during 1858. During Galveston's last yellow fever epidemic in 1867, thousands were afflicted and approximately 725 residents had died by early September. Improved sanitation and quarantines appeared ineffectual, though some argued that these reduced mortality and morbidity.
With dramatic improvements in sanitation and better control of the mosquitos that carry the yellow fever and dengue fever viruses, cholera, yellow fever, and dengue fever receded in importance. A few localized outbreaks of yellow fever occurred in Calvert, Brownsville, Laredo, and San Antonio between 1867 and 1903, and significant epidemics of dengue fever appeared in South Texas in 1907 and 1918.
Epidemics of other infectious diseases occurred during the twentieth century. The most prominent included influenza, polio, St. Louis encephalitis, and AIDS. During the fall of 1918 and the winter of 1919, an epidemic of Spanish influenza affected much of the civilized world. An estimated twenty-five million Americans experienced the disease; an estimated 550,000 died from the disease. During the fall months of 1918, many schools and businesses closed, and churches did not meet. In late October the Galveston schools closed for two weeks. By that time 5,000 cases had been reported in El Paso and 400 deaths had occurred. Since that time, various strains of influenza virus have afflicted Texans periodically. During the first week in January of 1944, for example, physicians reported 126,000 cases of influenza in the United States and 24,000 cases in Texas.
During the summer of 1943, 1,274 cases of poliomyelitis (infantile paralysis) were reported, the largest number ever recorded in the state. There were 168 deaths in this group. The total number of cases in 1943 more than doubled the cases reported in 1937. The epidemic in 1943 was most intense in the Panhandle. There were 996 cases confirmed for the entire state during 1945, and sixty-six counties reported 292 cases during the first six months of 1946. In Houston during 1948, 313 new cases were documented. The summer of 1952 was the worst epidemic period for both Texas and the nation as a whole. In the midst of a blistering heat wave, Texans watched the state polio totals climb to almost 4,000 cases. Not yet fully understanding the etiology and transmission of the disease, physicians struggled desperately to avert the sad results of infantile paralysis. Polio receded with the advent and use of vaccines during the mid-1950s.
More than once, St. Louis encephalitis frightened Texans. An epidemic involving 114 persons occurred in Cameron County in 1957. The first epidemic of this arbovirus disease in Houston occurred during the summer of 1964. Of 149 adults admitted to Ben Taub Hospital with signs of brain infection, 119 had positive serological tests for antibodies to the arbovirus causing this disease. Among the fifty children admitted to Ben Taub with signs of meningoencephalitis, twenty-six tested positive for these antibodies. Severe brain damage occurred in some of these patients. During the summer and fall of 1966 this disease afflicted 172 residents of Dallas, with twenty deaths. The most likely vector for these epidemics were the Culex mosquitos that flourished after summer rains.
With an initial appearance in the 1970s, AIDS (Acquired Immune Deficiency Syndrome) swept across the country and the rest of the world throughout the 1980s and 1990s. Scientists determined HIV (human immunodeficiency virus) as the cause for AIDS in 1984 and developed a diagnostic blood test for the disease. They soon discovered that, in addition to gay sex, the disease was transmitted through exposure to HIV-infected blood, blood transfusions, and heterosexual sex. In 1989 the Montrose Clinic in Houston became one of twelve test sites for the American Foundation for AIDS Research, providing greater access to experimental drugs by local patients. In 1996 retrovirus drugs were introduced that dramatically improved the outlook for patients suffering from HIV/AIDS. Expanded access of the drugs during the following decades has led to a steep decline in the number of deaths from HIV/AIDS. By the end of 2017 more than 90,000 Texans were living with HIV, according to the Texas Department of State Health Services HIV/STD Program.
Weather and infectious disease have long been intertwined. This fact has become increasingly evident during the first two decades of the twenty-first century with global warming and the subsequent rise of mosquito-borne and tick-borne diseases. Since 1999 Texas has experienced outbreaks of West Nile virus, Chikungunya, dengue fever, Lyme disease, and Zika. During the summer of 2012 Texas suffered a severe outbreak of West Nile virus with 1.868 reported cases. An eruption of the Zika virus became a global health concern in 2016. That year Texas reported 315 cases.
In late 2019 the coronavirus (COVID-19), linked to a Chinese poultry and seafood market in Wuhan, China, swept China and beyond causing respiratory illness and death throughout the world. The pandemic reached Texas with the confirmation of the first case by the Fort Bend County Health Department on March 4, 2020. On March 13, Governor Greg Abbott declared a statewide health disaster and authorized all resources needed to respond to COVID-19. The expeditious increase of cases throughout the following month brought about “Shelter-in-Place” orders for all Texas citizens. By early April the Centers for Disease Control reported almost 240,000 cases of the COVID-19 throughout the United States resulting in more than 5,400 deaths. More than 5,200 cases and 84 deaths were reported in Texas alone.