SMOKIN HEMI
12-23-2007, 03:45 PM
Spontaneous abortion may occur early or late into the pregnancy of a bitch. When spontaneous abortion occurs during the first or second trimester of the pregnancy, the fetuses will be resorbed. If prior confirmation of pregnancy has not been obtained, the owner may suspect failed breeding or infertility in the bitch. As such, diagnosis of the cause leading to early spontaneous abortions is often challenging.
Spontaneous abortions in the third trimester will result in expulsion of the fetuses and, therefore, greatly narrow the field for possible causes. Aborted fetuses and placenta should be collected and refrigerated (not frozen). Necropsy of the fetuses is often helpful for identifying conditions responsible for spontaneous abortion, however, results may not always provide a definitive explanation. Causes for spontaneous abortions may be either infectious or non-infectious conditions. The most common causes are discussed here.
http://<b><i><font face="Garamond, ...</font></i></b> (http://%3cb%3e%3ci%3e%3cfont%20face=%22garamond,%20times, %20serif%22%3einfectious%20causes%3c/font%3E%3C/i%3E%3C/b%3E)
<A href="http://%3cfont%20face=%22garamond,%20times,%20serif%22%3e %3cfont%20size=%224%22%3e%3cfont%20color=%22/#800040"><i><b>Brucellosis.</b></i></font></font></font>" target=_blank>http://<font face="Garamond, Times,...></font></font> Bacteria of the Brucella sp. are well known for inducing spontaneous abortion in the bitch. B. canis is the most common of the brucellosis-causing bacterial strains found in dogs and, as such, is routinely screened for by serological testing as part of the breeding management plan. Limitations to serological testing for B. canis, however, do exist and typically occur with use of the rapid slide agglutination test (RSAT) or the tube agglutination test which may result in false-positives or false-negatives. False-positives should be suspected if a dog is asymptomatic or concurrent blood cultures drawn at the same time as serological samples are negative for bacterial growth. Follow-up assessment with the agar-gel immunodiffusion (AGID) test will rule-out the possibility of false-positive results.
False-negatives will occur if serological testing is conducted within a 4 week period after the dog has initially contracted B.canis. Therefore, all negative tests should be confirmed by repeat testing 30 days from the first test before considering a dog to be free of infection.
B. canis infections in pregnant bitches will typically cause spontaneous abortions between 49 and 59 days after breeding, however, infections may also induce early spontaneous abortions with resorption of the fetuses, result in stillborn puppies, or cause death of puppies shortly after birth. A bitch that aborts a litter due to B. canis will demonstrate a brown or greenish-gray discharge that contains a large number of bacteria that will be infectious to both dogs and humans. Extreme caution, therefore, should be used when caring for a bitch suspected of harboring B.canis. At such point, collection of the vaginal discharge and specific culture testing for B.canis is usually sufficient to obtain the diagnosis.
Though B. canis is most often conceived as being transmitted from dog to dog during the actual act of copulation, the primary mode of transmission actually occurs via oronasal contact with infected body fluids. Therefore, spread of infection is not limited to breeding contact and as such, once introduced into a breeding kennel, the highly infectious B. canis will quickly spread through the population. Long-term, multiple treatments with antibiotics may assist in controlling symptoms and extent of infection within an individual dog, however, antibiotic treatment has limited efficacy for cure and the dog will remain potentially infectious to other dogs. As such, infected dogs should be neutered and removed from the breeding kennel environment to prevent spread to other breeding dogs. Retesting should be performed 6 months following completion of the antibiotic regimen to assess treatment efficacy. The alternative for controlling spread of B. canis is euthanasia of all confirmed-infected dogs.
Dogs may also become infected with other strains of Brucella sp. that typically infect livestock. Dogs with a history of spontaneous abortion, negative serological testing for B. canis, and exposure to livestock may harbor one of the other strains such as B. abortus, B. suis, and B. melitensis. Since serological tests for B. canis will not cross react with these other Brucella sp., dogs suspected of carrying an alternate strain of Brucella should be tested specifically for these other strains.
<A href="http://%3cfont%20face=%22garamond,%20times,%20serif%22%3e %3cfont%20size=%224%22%3e%3cfont%20color=%22/#800040"><i><b>Canine Herpesvirus Infection.</b></i></font></font></font>" target=_blank>http://<font face="Garamond, Times,...></font></font> Canine herpesvirus infection occurs as a relatively mild viral infection in the average dog, however, new infection in a pregnant bitch or newborn puppies will usually result in spontaneous abortion or neonatal fatality. Greatest risk occurs in the last three weeks of pregnancy and the first 3 weeks of birth. The virus is commonly found in dogs, and as many as 80% to 100% of dogs with a history of high exposure to other dogs (such as show dogs and kennel dogs) will be found to have life-long, latent states of infection (asymptomatic infection). Bitches that become infected with herpesvirus during pregnancy will usually experience pregnancy complications resulting in fetal death, fetal mummification, spontaneous abortion, or premature birth. Newborns that become infected with the virus usually succumb to septicemia. Additionally, surviving puppies will typically show indications of permanent nerve, kidney and lymphatic system damage. Bitches previously infected with canine herpesvirus may have normal pregnancies and litters without fatality, but at other times have a spontaneous abortion or lose puppies following birth. Outcome in bitches harboring infection prior to breeding appears to rely on the maternal immune system status at the particular point in time.
Serological testing showing any degree of titer for canine herpesvirus infection is considered positive since humoral immunity to this virus is minimal and short-lived. Monitoring titer, however, may provide an indication of viral "flare-up" at a particular point in time and may be helpful for assessing immune status and potential pregnancy complications in those bitches that have previously lost litters to canine herpesvirus complications. Additionally, serological titer is useful for diagnosis of canine herpesvirus as a cause for spontaneous abortion in the pregnant bitch. When abortion occurs late in the pregnancy, histopathological examination of tissues from the aborted fetuses can be used to confirm the presence of canine herpesvirus infection.
Spontaneous abortions in the third trimester will result in expulsion of the fetuses and, therefore, greatly narrow the field for possible causes. Aborted fetuses and placenta should be collected and refrigerated (not frozen). Necropsy of the fetuses is often helpful for identifying conditions responsible for spontaneous abortion, however, results may not always provide a definitive explanation. Causes for spontaneous abortions may be either infectious or non-infectious conditions. The most common causes are discussed here.
http://<b><i><font face="Garamond, ...</font></i></b> (http://%3cb%3e%3ci%3e%3cfont%20face=%22garamond,%20times, %20serif%22%3einfectious%20causes%3c/font%3E%3C/i%3E%3C/b%3E)
<A href="http://%3cfont%20face=%22garamond,%20times,%20serif%22%3e %3cfont%20size=%224%22%3e%3cfont%20color=%22/#800040"><i><b>Brucellosis.</b></i></font></font></font>" target=_blank>http://<font face="Garamond, Times,...></font></font> Bacteria of the Brucella sp. are well known for inducing spontaneous abortion in the bitch. B. canis is the most common of the brucellosis-causing bacterial strains found in dogs and, as such, is routinely screened for by serological testing as part of the breeding management plan. Limitations to serological testing for B. canis, however, do exist and typically occur with use of the rapid slide agglutination test (RSAT) or the tube agglutination test which may result in false-positives or false-negatives. False-positives should be suspected if a dog is asymptomatic or concurrent blood cultures drawn at the same time as serological samples are negative for bacterial growth. Follow-up assessment with the agar-gel immunodiffusion (AGID) test will rule-out the possibility of false-positive results.
False-negatives will occur if serological testing is conducted within a 4 week period after the dog has initially contracted B.canis. Therefore, all negative tests should be confirmed by repeat testing 30 days from the first test before considering a dog to be free of infection.
B. canis infections in pregnant bitches will typically cause spontaneous abortions between 49 and 59 days after breeding, however, infections may also induce early spontaneous abortions with resorption of the fetuses, result in stillborn puppies, or cause death of puppies shortly after birth. A bitch that aborts a litter due to B. canis will demonstrate a brown or greenish-gray discharge that contains a large number of bacteria that will be infectious to both dogs and humans. Extreme caution, therefore, should be used when caring for a bitch suspected of harboring B.canis. At such point, collection of the vaginal discharge and specific culture testing for B.canis is usually sufficient to obtain the diagnosis.
Though B. canis is most often conceived as being transmitted from dog to dog during the actual act of copulation, the primary mode of transmission actually occurs via oronasal contact with infected body fluids. Therefore, spread of infection is not limited to breeding contact and as such, once introduced into a breeding kennel, the highly infectious B. canis will quickly spread through the population. Long-term, multiple treatments with antibiotics may assist in controlling symptoms and extent of infection within an individual dog, however, antibiotic treatment has limited efficacy for cure and the dog will remain potentially infectious to other dogs. As such, infected dogs should be neutered and removed from the breeding kennel environment to prevent spread to other breeding dogs. Retesting should be performed 6 months following completion of the antibiotic regimen to assess treatment efficacy. The alternative for controlling spread of B. canis is euthanasia of all confirmed-infected dogs.
Dogs may also become infected with other strains of Brucella sp. that typically infect livestock. Dogs with a history of spontaneous abortion, negative serological testing for B. canis, and exposure to livestock may harbor one of the other strains such as B. abortus, B. suis, and B. melitensis. Since serological tests for B. canis will not cross react with these other Brucella sp., dogs suspected of carrying an alternate strain of Brucella should be tested specifically for these other strains.
<A href="http://%3cfont%20face=%22garamond,%20times,%20serif%22%3e %3cfont%20size=%224%22%3e%3cfont%20color=%22/#800040"><i><b>Canine Herpesvirus Infection.</b></i></font></font></font>" target=_blank>http://<font face="Garamond, Times,...></font></font> Canine herpesvirus infection occurs as a relatively mild viral infection in the average dog, however, new infection in a pregnant bitch or newborn puppies will usually result in spontaneous abortion or neonatal fatality. Greatest risk occurs in the last three weeks of pregnancy and the first 3 weeks of birth. The virus is commonly found in dogs, and as many as 80% to 100% of dogs with a history of high exposure to other dogs (such as show dogs and kennel dogs) will be found to have life-long, latent states of infection (asymptomatic infection). Bitches that become infected with herpesvirus during pregnancy will usually experience pregnancy complications resulting in fetal death, fetal mummification, spontaneous abortion, or premature birth. Newborns that become infected with the virus usually succumb to septicemia. Additionally, surviving puppies will typically show indications of permanent nerve, kidney and lymphatic system damage. Bitches previously infected with canine herpesvirus may have normal pregnancies and litters without fatality, but at other times have a spontaneous abortion or lose puppies following birth. Outcome in bitches harboring infection prior to breeding appears to rely on the maternal immune system status at the particular point in time.
Serological testing showing any degree of titer for canine herpesvirus infection is considered positive since humoral immunity to this virus is minimal and short-lived. Monitoring titer, however, may provide an indication of viral "flare-up" at a particular point in time and may be helpful for assessing immune status and potential pregnancy complications in those bitches that have previously lost litters to canine herpesvirus complications. Additionally, serological titer is useful for diagnosis of canine herpesvirus as a cause for spontaneous abortion in the pregnant bitch. When abortion occurs late in the pregnancy, histopathological examination of tissues from the aborted fetuses can be used to confirm the presence of canine herpesvirus infection.