Controlling Cattle

Fever Ticks

The rugged cowboys that dominated the American

television screen in the 1950’s may have faded away,

but real cowboys still ride the range—make that the

river banks—of the Rio Grande. These cowboys

work for the U.S. Department of Agriculture’s (USDA)

Animal and Plant Health Inspection Service (APHIS)

and are looking for the ticks that cause cattle fever,

another term for babesiosis.

Known as “tick riders,” these cowboys first

appeared in 1906 as part of the Cattle Fever Tick

Eradication Program (CFTEP), one of the first cooperative State–Federal eradication efforts. Through

the CFTEP, the tick riders helped eradicate the existing infestation of cattle fever ticks in the United States

and prevented the introduction of new cattle fever

ticks from Mexico. They did so by using horseback

patrol and systematic quarantines along the Rio

Grande River. By 1943, the tick riders had helped

eradicate the two species of cattle fever ticks from

the United States, with the exception of a permanent

quarantine zone between Texas and Mexico.

The ticks of interest to the APHIS tick riders are

the cattle fever tick (Boophilus annulatus) and the

southern cattle tick (Boophilus microplus). These

pests are responsible for the spread of a severe and

often fatal disease of cattle, commonly known as

Texas or cattle fever. The disease, spread through a

parasite that destroys red blood cells, was eradicated

from the United States by CFTEP between 1906 and

1961.

Background

Spanish colonists first brought both types of 

cattle fever ticks and cattle fever disease to the

United States through the introduction of infested 

cattle. Currently, both types of ticks infest most 

tropical and subtropical areas of the Western

Hemisphere. They frequently are found in the part of

Texas that borders on infested parts of Mexico and

are occasionally found in California. Florida had outbreaks of cattle ticks in the 1950’s and in 1960.

Clinical Signs

Cattle with the acute form of tick fever (generally

contracted during the summer) develop high temperatures (107% or 108% F) and stand with their heads

lowered and backs arched. They experience a loss

of appetite, constipation followed by diarrhea, and

decreased milk production. “Red water,” or bloodstained urine, is common. Death usually comes 

within 3 or 4 days after fever develops.

Cattle affected with the chronic form of cattle

fever (contracted in late autumn and winter) develop

a mild fever and stop eating and chewing their cuds.

They also develop anemia and lose weight rapidly.

The chronic form of the disease lasts for many

weeks. Some deaths occur, but most animals 

recover gradually.

Surviving animals may display nervousness

known as “tick poverty” or “tick worry”—they become

weak, stunted, and anemic from the continuous loss

of blood. Ticks can reduce the weight of a

1,000–pound steer by 200 pounds in a year. Infected

cattle frequently have relapses 3 to 6 weeks after

their temperatures return to normal and become 

susceptible to other diseases or secondary infections.

In summer, the incubation period (the time from

when an animal becomes infected until it first shows

disease signs) is usually 10 to 15 days after the

infected larvae, or seed ticks, begin feeding on the

animal. In winter, it may take as long as 90 days.

Ticks’ Life Cycle

Cattle fever ticks spend the early part of their

lives on the ground. Eventually they infest cattle,

or–occasionally– horses, mules, sheep, goats, or

deer. The ticks must have blood from an animal host

to complete their life cycles.

Newly hatched seed ticks, or larvae, are barely

visible to the unaided eye. These waxy brown, 

six-legged ticks crawl up grass or plants where they

wait for an animal to pass by. If ticks do not find a

host, they eventually die of starvation. In summer,

seed ticks may starve after 3 to 4 months; in colder

periods, they may survive for 6 months.

Usually seed ticks first attach themselves to soft

skin inside the animal’s thigh, flanks, and forelegs or

along the belly and brisket. There, they suck blood,

or engorge. Then these ticks molt twice: seed ticks

become tiny, white,eight–legged nymphs; after

engorging about a week, nymphs molt to become

adults. Many adult ticks are olive green; others are

mottled yellow or olive brown.

Eradication

Cattle fever has caused enormous losses to the

U.S. cattle industry in the past. Before the nationwide

eradication program began in 1906, direct and indirect economic losses were estimated to be $130.5

million (which would be approximately $3 billion

Factsheet

Veterinary Services February 2002

APHIS
today). If the ticks had not been eradicated from the

United States, the cattle industry’s losses from ticks

could amount to approximately $1 billion annually.

Current Activities

The tick riders, working through CFTEP, still patrol

the Rio Grande river on horseback. The highly successful program currently consists of 57 inspectors, 7

supervisors, and a director of field operations, with 2

assistants. The quarantine or “buffer” zone extends

over 900 miles from Del Rio, TX, to the Gulf of

Mexico, and is 200 yards to 6 miles wide. Outbreaks

outside the zone are rare. Premises found to be

infested with cattle fever ticks are placed under 

quarantine for 6 to 9 months, depending on the time

of year.

APHIS tick riders detect and apprehend any 

illegally entered (stray or smuggled) Mexican livestock

or native livestock that have crossed into Mexico and

returned. APHIS officials inspect and dip all native

livestock being moved within or out of the buffer zone

in pesticides that kill ticks without injuring the animals.

Although a single treatment kills all the ticks on an

animal, it will not assure eradication because it does

not prevent reinfestation. Only long-range programs

can rid an area of ticks. For this reason, APHIS dips

cattle at regular intervals for at least 1 year following

direct or presumed contact with the pest.

Without these controls, cattle fever ticks would

reinfest areas of the United States that have warm 

climates.

If Your Cattle Have Ticks

If you suspect that your cattle have cattle fever

ticks or you do not know the species infesting your

cattle, ask an APHIS tick inspector or your local veterinarian to have the ticks identified and give you

information about control or eradication. Each suspect animal should be chute-restrained so an experienced person can make a dry-scratch inspection.

State and Federal inspectors regularly examine cattle

throughout the infested buffer area until all cattle fever

ticks are eradicated.

Chemical dips—when properly used—kill ticks on

animals without injuring the animals. You may obtain

the names of the permitted dips from your veterinarian, State or Federal disease control officials, or the

Federal veterinarian in charge of your State. Every

animal in every infested and exposed herd must be

treated.

Getting the Word Out

The ultimate goal of the CFTEP is to completely

eliminate cattle fever ticks from the United States.

Success of the program not only prevents exposure of

U.S. livestock to babesiosis but allows the annual

importation of hundreds of thousands of Mexican cattle, a large number of which are presumed to be

infected with the disease, while protecting the U.S.

cattle industry.

As part of its increased surveillance activities,

APHIS is continuing an education effort to inform U.S.

cattle producers and veterinarians about this pest and

the disease that it causes.

For more information, contact:

USDA, APHIS, Veterinary Services

National Center for Import/Export

Animals Program

Telephone: (301) 734-8170

or

USDA, APHIS, Veterinary Services

Emergency Services

4700 River Road, Unit 41

Riverdale, MD 20737-1231

Telephone: (301)734-8073

The U.S. Department of Agriculture (USDA) prohibits discrimination

in all its programs and activities on the basis of race, color, national

origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to

all programs.) Persons with disabilities who require alternative

means for communication of program information (Braille, large

print, audiotape, etc.) should contact USDA’s TARGET Center at

(202) 720–2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of

Civil Rights, Room 326–W, Whitten Building, 1400 Independence

Avenue, SW, Washington, DC 20250–9410 or call (202) 720–5964

(voice and TDD). USDA is an equal opportunity provider and

employer.

United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture