TEXAS FEVERTEXAS FEVER

From 1865 to presentFrom 1865 to present

What is Texas Fever?What is Texas Fever?

• In June 1868 a fatal outbreak was reported among cattle in Illinois.

• It was characterized by high fever, anemia, emaciation, and diarrhea.

• NINE OUT OF TEN cattle who got the sickness died.

Why not Illinois Fever?Why not Illinois Fever?

But if the outbreak occurred in Illinois, why was it called Texas Fever?

The MysteryThe Mystery

Settlers quickly discovered that whenever healthy Texas longhorns mixed with mid-

western cattle from Kansas, Missouri, Illinois, and Oklahoma, the mid-western

cows became ill with the disease.

But WHY was this But WHY was this Important?Important?

Cattle Drives 101Cattle Drives 101

• In 1865 there was a great demand for beef on the eastern coast of the US where supplies of cattle were severely depleted from the recently ended Civil War.

• Meanwhile, there was a plentiful supply of cheap cattle in Texas and other southwestern territories.

Cattle Drives 101Cattle Drives 101

• Texas cattle ranchers and entrepreneurs began hiring many cowboys to round up and brand the unclaimed cattle and to move them to the eastern markets.

• Unfortunately, most of the Texas rangelands were isolated from any easy transportation to the east.

Cattle Drives 101Cattle Drives 101

• The task of the cowboy was to take part in cattle drives where cattle were driven from Texas to the railroad cow-towns.

Cattle Drives 101Cattle Drives 101

• Between 1866 to 1895 some 10 million cattle were taken to the railroad cow-towns by way of cattle trails. These trials were over 1,000 miles long and would take between 12 and 16 weeks to complete.

The DisagreementThe Disagreement

• To protect their own cattle from Texas Fever, states on the cattle trail, such as Kansas and Missouri, closed their borders to Texas cattle.

• The Texans became angry and attempted to defy the quarantines. They claimed that the disease could not possibly come from their cattle because they did not get sick.

Because the Texas longhorns did not seem to be infected by the disease, many

people developed a great fear and respect for the Texas cattle. Even some of the Texas cowboys who herded the cattle north refused to slaughter the animals.

To the CourtsTo the Courts

In 1877, Texas took their battle to the U.S. Supreme Court and won. The court declared the laws of Kansas and Missouri closing their

borders unconstitutional as they hindered interstate commerce.

However, the damage had already been done. Once

the states closed their borders, the era of the

cattle drives was effectively ended, as

many of the main trails, including the Shawnee

and Chisholm trails, were never to be used again.

The End of the Cattle DrivesThe End of the Cattle Drives

Inspection StationsInspection Stations

• But now that the Supreme Court allowed Texas longhorns to be sent north, mid-western cows started becoming sick again.

• The states tried to set up inspection stations at border crossings, but they were easy to avoid because of the widely unsettled state borders.

Bureau of Animal IndustryBureau of Animal Industry

So under pressure from the states, the federal government created the Bureau of Animal Industry in 1884, with the intent to regulate cattle traffic and suppress bovine

diseases.

Bureau of Animal IndustryBureau of Animal Industry

The Bureau of Animal Industry employed

many bright scientists to try and discover the

cause of this mysterious illness.

What was this mysterious illness?What was this mysterious illness?

Since the midwestern cows became sick after being mixed with Texas longhorns or grazing in the pasture soon after they were

gone, many people thought that the longhorns generated toxic waste that killed

the other cows.

Louis PasteurLouis Pasteur

However, another idea stemmed from the

experiments of Louis Pasteur, known for his demonstration of

germ theory of disease.

The DiscoveryThe Discovery

• This led to the discovery in 1893 by two scientists Theobald Smith and Frederick Kilborn who found the microscopic organism responsible for Texas Fever, a protozoan they named Babesia bigemina.

The Workings of the ParasiteThe Workings of the Parasite

It was discovered that the parasite first enters the infected animal’s bloodstream,

and then inhabits and destroys the red blood cells.

New Name for an Old DiseaseNew Name for an Old Disease

The new name of Texas Fever became bovine babesiosis, after the protozoan that causes it. This is the current name that is

still used around the world.

The whole mystery was not solved The whole mystery was not solved yetyet

How did the protozoan infect the cattle?

A ClueA Clue

• One important clue was when the Texas longhorns spent the winter in the north, they no longer infected the mid-western cattle.

TICKS!TICKS!

This led many people to suspect that cattle ticks were involved

somehow.

They were correct!They were correct!

• The same scientists that discovered the protozoan found the vector to be cattle ticks.

• The ticks sucked blood from an infected animal, dropped in the grass, laid eggs and hatched young ticks harboring the protozoan, ready to infect more cattle.

Many settlers thought that the longhorns poisoned the grass, which was partially correct. The ticks dropped off

of them and hid in the grass, ready to infect another animal.

Ticks as the VectorTicks as the Vector

• But when the Texas longhorns spent the winter up north, the ticks died from the colder temperatures.

• And without the vector, there was no disease!

Blood-sucking InsectsBlood-sucking Insects

• This was a very important breakthrough because it marked the first time a blood-sucking insect transmitted a disease.

• This later led to the discovery of mosquitoes as vectors for malaria and yellow fever.

But this was But this was STILLSTILL not the whole story not the whole story

Why were the Texas longhorns not affected by the cattle ticks?

Only in modern times can we Only in modern times can we understand whyunderstand why

• It turns out that the Texas longhorns had developed an immunity to the parasitic protozoan.

• When the calves were born, they had a natural partial resistance to the infection from antibodies in their mother’s milk.

Texas Longhorns had ImmunityTexas Longhorns had Immunity

The calf would only suffer a mild non-fatal attack, and then develop resistance to the parasite. When the calf became an adult

cow, it maintained its immunity by constantly becoming re-infected by tick bites, remaining a carrier of the disease.

But non-Texas cattle did notBut non-Texas cattle did not

When a cow from the mid-west was

introduced to the infected ticks, they did

not have any immunity to the

parasite they harbored, and the

illness quickly became fatal.

Breaking the TransmissionBreaking the Transmission

After discovering that without the ticks the illness disappeared,

the Texas cattle were dipped in arsenic, beginning with the

first dipping vats on the King Ranch in

1903.

VaccinesVaccines

When Northern cattle were brought in to Texas, they could be immunized with small amounts of blood from infected animals, a type of vaccine

known as a live vaccine.

Finally!Finally!

Even with all of these efforts, the disease was not eradicated in the United States

until 1942.

In modern times…In modern times…

Cattle fever in the rest of the worldCattle fever in the rest of the world

The disease still inflicts millions of cattle all over the world, in places such as

Southern Europe, South America, South Africa, the West Indies, and Australia.

A New Threat from an Old EnemyA New Threat from an Old Enemy

The disease is also starting to come back to Texas. Although Texas has gotten rid of the ticks, Mexico still has problems with them. Because of our increased trade relations with Mexico, the disease is once again threatening our cattle population.

““Tick Riders”Tick Riders”To maintain the safety of

our Texas cattle, Texas officials have created a “permanent quarantine zone” on the border of

the Rio Grande, patrolled by 60 USDA

“tick riders” on horseback who

apprehend and inspect stray livestock in the

zone.

Safety of our CattleSafety of our Cattle

• Texas Animal Health Commission field personnel also are trained to collect and identify ticks, as there is always a chance that fever ticks could be carried northward, or other dangerous foreign ticks could be introduced from other parts of the world.

ConclusionConclusion

• Texas cattle fever nearly single-handedly ended the cattle drives of the 19th century. Even with extensive efforts of eradication, the parasite still infects millions of cattle around the world. However, through solving this mystery, we have gained knowledge about the source of disease, leading to the eradication of many other diseases.