SEP 14 154'
Veterinary Science Mimeograph July, 195l
Series No. $5-1
UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
WILLIARD M. FIFIELD, Director
LUNGWORM DISEASE OF CATTLE
Leonard E. Swanson, Walter R. Dennis and William M. Stone, Jr.
Lungworm disease of cattle is caused by a long, thin, white worm,
technically known as Dictyocaulus viviparus. The life cycle is direct,
no intermediate host is required. The larvae are passed from the
animal in the feces and become infective to calves or adult animals on
the fourth day. This parasitic disease is very prevalent throughout
Florida, especially where calves and older cattle have access to muck
lands, wet areas, deep shade, swamps, or drainages from barns or corrals.
In the areas mentioned above it is nearly impossible to raise replacement
dairy heifers. Beef calves from four months to yearlings suffer from the
ravages of this parasite. Many dairymen have lost their entire calf crop,
and beefmen have lost up to 30 percent of their calf crop. The biggest
loss, however, is not in the actual deaths but rather stunting the growth
of recovered animals.
HISTORY ANT SYMPTOMS
Usually the owners will report that they weaned the best crop of
calves and all of a sudden the animals begin to go off feed and lose
weight. The calves will stand out from the herd. Coughing is very
prevalent, especially if excited. The bowel passages may be normal or
the animal may be constipated, and many will show diarrhea. The mouth is
held open with a pronounced abdominal type breathing. Occasionally a
calf will be seen with the tongue protruding, ears drooping, and eyes glassy.
A frothy creamy colored mucous will be noted running from the nostrils
or mouth and the infected calf continually licking its nose. When the
animal becomes too weak to eat or stand it goes down and dies in a
semi-coma stage, usually without a struggle.
The blood is dark red. There is bilateral pleurisy (inflammation of
chest cavity), with straw colored fluids in the thoracic and abdominal
cavities. The entire carcass is emaciated, showing edematous infiltration
of the lymph glands, mesentery, momentum, heart and kidneys. The trachea and
bronchial tubes are filled with a yellowish-white frothy exudate mixed with
adult worms, embryonated ova and larvae. The bronchial lymph glands are
extremely large and gelatinous in appearance. There is heavy congestion
of the lung tissue with marked lobar pneumonia. The bronchioles and
trachea may be reddish in color but usually are clear. No pus has been
observed in these pneumonia cases having lungworms.
Death is a result of suffocation, lack of oxidation of the blood and
LONGEVITY OF ADULT WORMS
Naturally infected calves placed in concrete pens will be free of
lungworm larvae in from 69 to 180 days, depending upon the severity of
infection. Adult bulls and cows, when exposed to infected areas, will
carry light loads, constantly reinfecting the premises, yet they will
show no symptoms of the disease.
The larvae are recovered from the feces by means of a Baerman
apparatus. Lungworm larvae in fecal samples varies from 1 to 6,084
per gram feces depending upon the severity of the infection. Four day
old larvae given to parasite-free calves by mouth were able to establish
themselves in the lungs, and larvae were recovered in the feces of
experimentally infected animals in from 18 to 33 days. Embryonated
ova are found in the bronchiole, whereas free larvae are found in the
trachea, stomach and small and large intestines. The larger numbers of
larvae are found in the caecum and rectum. The highest daily output
(24 hours) of larva from any one calf on test was 18,900, however,
calves with much greater numbers of larvae in the feces died before
a 24 hour check could be obtained.
LIFE HISTORY OF LUNG WORMS
The lung worms of cattle are direct infectors, the adult Worms
live in the bronchioles and trachea of the animal, male and females
mate, the female lays her eggs which contain a larvae. The eggs hatch
in the trachea and/or digestive tract of the host. Those larvae or eggs
which are coughed up are swallowed, pass on out the animal with the
ingesta to the ground. Upon reaching the ground in feces and in the
presence of moisture, these larvae develop into infectious larval stages
in four to seven days. The infective larvae crawl upon blades of grass
where they are eaten by grazing animals. Their journey through the host
body has not been worked up, however, they reach the lungs and are
producing eggs within 18 to 33 days after taken into the body of the
host. They are probably carried from the stomach or small intestine
by the blood stream to the lungs.
OTHER PARASITIC INFECTIONS
All calves observed with natural infections of lungworms were also
carrying heavy burdens of stomach and intestinal parasites. A typical
parasite infection found on necropsy is as follows:
Number Location Kind
200 Stomach Haemonchus contortus Wireworms
8,600 Stomach Ostertagia ostertagi Threadworms
2,h00 Stomach Trichostrongylus axei Bankrupt worms
10,,00 Small Intestine Strongyloides spp. Microscopic worms
53,900 Small Intestine Cooperia spp. Threadworms
100 Small Intestine Buonostomum phlebotomum Hookworms
787 Large Intestine Oesophagostomum radiatum Nodular woTms
61 Large Intestine Trichuris discolor Whipworns
5,389 Bronchial tubes Dictyocaulus viviparus Lungworms
Other calves had like infections, although many were more fortunate
and carried only light infections of the stomach and intestinal parasites.
One hears many suggestions and sees few writings on the control of
lungworms in calves. Good feeds, protection from adverse weather con-
ditions, and removing animals from low, wet, shady places are recommended.
Good management practices are:
1. Creep feed the calves during their nursing or milk feeding
period to promote growth and to prevent the shock from sudden
change of feeds.
2. Rotate pastures frequently and do not allow animals to crop
grasses too close to the earth.
3. Use heavy muck lands and deep shaded areas for fattening
older cattle intended for slaughter.
U. Place dairy calves above barns or older cattle yards and
on well drained areas.
$. Segregate age and sex groups.
6. Remove visibly sick animals from the herd.
7. Infected calves should be placed on high, dry areas, given
free access to good hay, concentrates and minerals, and if
available, citrus or sugar cane molasses. All feeding should
be done from racks or bunkers. DO NOT FEED ON GROUND. Always
have your calves checked for parasites, especially stomach and
8. Treat all infected calves with the proper dosage of phenothia-
zine, small doses should be given extremely weak animals the
first time, and repeat the dosage in 21 days, using therapeutic
schedule on package. If necessary, continue the dosing every
21 days until stomach and intestinal parasites are reduced and
calves show improvement. This method will eliminate most of the
parasites, giving the calf an opportunity to throw off the lung-
worm infections. If calves are not treated and properly fed as
outlined, they will die from parasite infections.
TREATMENT FOR REMOVAL OF LUNGJORMS
All attempts to remove these worms from the lungs of calves have
failed. Various drugs administered directly into the lungs by inhalation,
hypodermically or by mouth are ineffective.
Experiments are in progress studying the life history and means of
destroying the adult parasites in the lungs, the larvae in the feces
and/or on pastures.