Maternal environmental stresses |
Infectious agents gain access to the pregnant uterus via the
blood stream or through the cervix. These can cause placental
dysfunction leading to fetal death and in some cases may infect
fetuses directly. |
Brucella canis |
The most common bacterial cause of abortion in the bitch.
Abortion occurs between 45 and 55 days of pregnancy. Infertility
follows infection and abortion. Vaginal discharges and aborted fetal
tissues are highly infectious to other females. |
Staphylococcus aureus
Streptococcus spp.
|
These are frequently cultured from vaginal discharges or from
fetal tissues after abortion. Their role in causing abortion is
unknown. May be associated with infertility, persistent vaginal
discharge and repeat abortions in older bitches. |
Mycoplasma spp.
Ureaplasma spp.
|
These are opportunistic organisms normally found in the vaginal
canal. In large enough numbers, they may cause infertility, early
embryonic deaths, resorptions, abortions, stillbirths and weak,
nonviable pups. |
Canine herpesvirus |
Infections in newborn puppies are fatal. Causes vaginitis in the
bitch. This virus can cross the placenta and infect puppies,
resulting in fetal death, mummification, abortion, premature birth
or delivery of weak, nonviable pups. |
Canine distemper virus |
May cause spontaneous abortion with or without fetal infection.
Often abortion results from the stress of the clinical
disease. |
Canine adenovirus (infectious hepatitis) |
May cause spontaneous abortion with or without fetal infection.
Often abortion results from the stress of the clinical
disease. |
Toxoplasma gondii |
Protozoal parasite causing mild disease in adult dogs. May be
more severe when present with distemper virus, which is known to
suppress the immune system. Fetal infection may occur and
Toxoplasma gondii has been found in milk of lactating
bitches. |
Neospora caninum |
Recently identified protozoal parasite that resembles
Toxoplasma gondii, can infect brain and spinal cord of
developing fetuses or neonates. Newborns have progressive muscular
weakness leading to death. |
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With any
abortion, the bitch should be presented to a veterinarian as soon
as possible for a complete physical examination and collection of samples
for diagnostic testing. In most cases, these diagnostic procedures will
not save the pregnancy, but they will help identify the appropriate
supportive medical therapy and the management practices necessary to
prevent future abortions. Several possible infectious causes of early
embryonic deaths and abortion are listed below.