Neospora caninum Infection And Abortion In Cattle
Robert Munson, PADLS Field
Investigation Unit, the University
of Pennsylvania School of Veterinary
Medicine, New Bolton Center
Neospora caninum is a common coccidian parasite of
cattle that usually causes an unrecognized infection. It has a
worldwide distribution and infects all breeds of cattle. The
disease is most commonly associated with abortions but de
creased milk production in first calf heifers and the birth of
calves that can not stand have also been seen.
The organism was first recognized in dogs in 1980 and
was linked to an abortion epidemic in a New Mexico dairy
in 1989. In 1998 the dog was recognized as the definitive
host (animal where the entire life cycle of the parasite can be
completed). The dog eats infective stages of the parasite and
subsequently passes infective organisms in its feces. The cow
and a variety of other animals are intermediate hosts
(animal where infection occurs by eating infective stages or
transmission from an infected dam but the parasite is not
passed in the feces). After infection occurs in the intermedi
ate host, the organism is found in cysts in muscle and other
tissues. These tissue cysts are infective if they are eaten un
cooked by the dog and possibly other canids.
The infection in cattle is life long and is transmitted from
infected dam to offspring before birth. This mechanism per
petuates the infection from generation to generation and ef
fectively maintains the infection in a herd. Before the dog
was recognized as the definitive host, this was the only
known method of transmission.
Abortion is the only clinical sign observed in infected
cows. Cows of any age may abort between 3 months of ges
tation and term but most Neospora induced abortions occur
at 5-6 months of gestation. The abortions can occur at any
time of the year and may infect only a few cows or as many
as 30% of cows in a herd.
Ventilation Systems: Air Quality Is the Goal
Dan F. McFarland, Extension Agent
Agricultural Engineering
Penn State Cooperative Extension
Livestock shelters can be ventilated naturally or mechani
cally, but the common goal is the same - provide good air
quality for the animals and their caretakers.
Good air quality is essential for good animal health and
efficient production. Poor air quality can lead to respiratory
complications, reduced animal comfort, and wet, undesir
able conditions.
Designed and managed properly, ventilation systems can
provide good quality air to the entire animal space in dairy,
swine and beef shelters. Before evaluating or selecting a ven-
Clinical signs
Animal Housing
Fetuses may die in utero, be resorbed, mummified, de
composed, stillborn, bom alive but diseased or born clini
cally normal but chronically infected. Animals that abort
may abort again in subsequent pregnancies. Infrequently
calves are born with signs that their central nervous system
has been damaged and/or are unable to stand.
Post mortem examination of an aborted fetus and the
demonstration of the Neospora caninum organism is needed
to make a diagnosis. The examination of blood samples
from aborting cows can be used to confirm the postmortem
diagnosis.
There is currently no treatment to prevent the transmis
sion of infection from infected dam to fetus.
Control
Although there is limited information on the frequency of
shedding of infective organisms by the dog, it is important
to prevent fecal contamination of cow feed or water by dog
feces. Dogs should not be allowed to eat aborted fetuses,
fetal membranes or dead calves. (This is the ideal way to
complete the life cycle of the parasite.) Feed should not be
stored on piles where dogs or other wild animals have easy
access.
There is no treatment other than culling to prevent the
transmission of the infection from dam to calf. There is no
proven vaccine for preventing Neospora induced abortion in
cattle or the shedding of infective organisms by dogs. There
is a conditionally licensed vaccine available in Pennsylva
nia. For conditional licensing the vaccine has demonstrated
it can cause an antibody response in cattle and that is safe
(no decrease in milk production or adverse reactions). It has
not been shown to be effective at controlling the transmis
sion of this organism.
tiiation system, it is important to understand what “good air
quality” is.
The levels of moisture, gases, and pollutants typically
determine the quality of a volume of air. These levels are
controlled by bringing fresh air into the animal area, mixing
it with air already in the building, then exhausting the com
bination from the building.
An air exchange is accomplished by creating a pressure
difference between the inside and outside of the building'
Mechanical ventilation systems use fans and inlets to create
the pressure difference, while naturally ventilated struc
tures rely on wind and heat produced by the animals.
(Turn to Pago 23)
Diagnosis
Treatment