Brucellosis is an important venereal disease in many species. It is caused by infection with a bacteria from the genus, Brucella. It does not usually come up in pet ownership because most pet dogs are not used for breeding. Once someone has decided to breed their dog, though, it behooves them to know all about this disease, particularly since it can be transmitted to humans. If you are planning to breed your dog, test your dog and insist that the owner of your dog’s mate produce results of a recent test for your inspection prior to breeding. All actively bred studs should be tested every 6 months.
There are six species of Brucella. The most common species infecting the dog is Brucella canis, however dogs can certainly become infected with Brucella abortus (from cattle), Brucella melitensis (from goats) and Brucella suis (from pigs) if they are allowed to drink contaminated milk or eat leftover birth membranes, contaminated meat, or aborted young. (The other two species are Brucella ovis, which affects only rams, and Brucella neotomae, which affects desert mice.) Luckily for humans, Brucella canis causes much less serious disease in humans than do the livestock Brucellae, but the health department still considers any Brucella infection reportable.
Dogs like to stick their noses in all sorts of nasty places. They also chew up all sorts of disgusting things. Brucellosis can be contracted sexually, but it can also be contracted by inhalation (sniffing contaminated urine or fetal membranes), through the eyes, or orally (licking contaminated urine or urogenital secretions, or chewing up fetal membranes). Urine and saliva from an infected dog are not nearly as contagious as urogenital secretions. It is when breeding and/or whelping is in the picture that the transmission risk becomes very high.
When a female dog aborts a pregnancy because of a Brucella infection, she continues to secrete fluids packed with Brucella bacteria for 4 to 6 weeks.
The organism requires an average of three weeks to become evident in the bloodstream. After that they localize in the reproductive or urinary tract, and either continuously or periodically seed the bloodstream from there. Lymph nodes can enlarge, and possibly the spleen or liver can become inflamed, but generally the infected adult dog does not seem sick. Chronic disease from long-term immune stimulation can result. This can include:
Discospondylitis (inflammation of a disc in the spine)
Uveitis (deep eye inflammation)
Multiple joint arthritis
Glomerulonephritis (kidney inflammation and protein loss)
Most of the time, the only sign is aborted pregnancy between the 45th and 59th day of pregnancy (relatively late in the pregnancy). Classically, the aborted pups appear to have died at least several days prior to abortion, as they do not look freshly dead. Abortion does not always appear in this most common form, though. Sometimes the pregnancy is lost much earlier and is deemed to represent infertility. Sometimes puppies are still born. Sometimes they are born live and infected.
Direct culture of the organism from a dead puppy, from an infected dog’s blood, or from a secretion is confirmatory but the organism is difficult to isolate in this way. This means we usually depend on immunologic tests. Which test is selected depends on what the test is being used for.
The RSAT (Rapid Slide Agglutination Test) is a screening test that can readily identify negative dogs. That is, if the test comes out negative, the dog can be considered negative. If the test comes out positive, further testing is needed. Up to 60% false positives occur. A test kit is available for use inside the veterinary hospital and some facilities can perform this test while you wait.
The IFA (Immunofluorescent Antibody) test is a similar screening test but it must be sent to the reference laboratory. The same guidelines apply: negative means negative, positive means do further tests.
There are two tests that fit in this category. The most specific test (meaning the most trustworthy positive value) is the AGID (Agar Gel Immunodiffusion) test. A version of the test called the CPAGID (named for the bacterial protein it detects) is the most accurate of all.
Another test is called a TAT (Tube Agglutination Test). It looks for antibodies against Brucella canis. Antibiotic treatment with tetracyclines can drop antibody levels low enough for the TAT to be negative but this does not necessarily indicate that the infection has cleared. At this time the CPAGID is favored over TAT.
If a dog is to travel to Australia, a TAT test is required as part of the travel documentation.
If a dog is to travel to New Zealand, an AGID test is required as part of the travel documentation.
First of all, the infected dog must be removed from the breeding program (spayed, neutered or euthanized) and isolated from any animals to be used for breeding. The dog can remain as a pet, but probably should not be sold due to potential health risks to potential buyers. For pet dogs, a course of antibiotics can be given, but since this bacterium is so good at hiding inside the host’s cells, one can never assume it is ever truly gone. Some people keep their dogs on tetracycline for life. Dogs do recover from this infection without treatment, but it can take up to five years. Naturally-recovered dogs cannot be reinfected; antibiotic-treated dogs can be reinfected. Human health must be considered in the decision to keep and treat an infected dog.
A new dog for a breeding kennel should be isolated for one month. Two Brucella tests one month apart should be adequate to confirm negativity (it takes about three weeks from infection for tests to turn positive). If an infection is detected in a kennel, the entire kennel population should be evaluated.
References: Portions of this handout were taken from this source:
Canine Herpes Virus
A name given to a group of cancers arising from the malignant transformation of lymphocytes (a type of white blood cell).
Most of us are familiar with herpesviruses because we have heard of human herpes. Medications to suppress herpes outbreaks are advertised on television and educational programs are in place in schools and communities. In humans, there are two herpesviruses: herpes I, which causes facial sores and is spread by kissing or sharing food utensils, and herpes II, which causes genital sores and is spread by sexual contact. Herpesviruses have the ability to hide in the body’s nerve ganglia, where they are safe from the immune system, periodically emerging and causing symptoms. Herpes infection is generally considered to be permanent and outbreaks of symptoms are generally associated with stress.
In fact, our pets must deal with their own herpesviruses. In cats, herpes is a respiratory virus accounting for nearly 50% of feline upper respiratory infections. Feline herpes is very contagious and is a common problem wherever cats are housed in groups.
Canine herpes is more of a reproductive problem than a respiratory one. In fact, most infected dogs do not appear to get sick at all; the virus affects the unborn and newborn.
Herpes infection manifests in pregnancy as resorption of the embryos, abortion of the fetuses, stillbirth, or death of puppies within a few weeks of life. Transmission occurs by direct contact (sexual contact will do it but the usual route is simply normal nosing, licking, and sniffing) between the infected and uninfected dogs. For this reason, it is recommended that a pregnant female dog be isolated from other dogs for the last three weeks of pregnancy and the first three weeks after birth.
Let’s say that again: Any pregnant female dog should be isolated from other dogs for the last three weeks of pregnancy and the first three weeks after birth. If she gets infected during this period, the litter is likely to be lost.
Puppies can be exposed before, during, or after birth. Just because one member of the litter is infected does not mean they all are. The incubation period is 3 to 7 days following infection. Once symptoms begin (shallow breathing, loss of appetite, vomiting) death follows within 48 hours. Infected puppies uniformly have low platelet counts and may show red spots called petechiae that actually represent small bruises.
The necropsy (veterinary word for autopsy) is the only realistic means of finding out what happened. If you want to find out if the other litter members are at risk or if the mother dog can safely be bred again, the dead puppy should be examined.
Place the remains in a zip-lock plastic bag and refrigerate it until you can notify your veterinarian. If the placenta is available, it should be included.
Expect the mother dog and remaining littermates to be examined and the dead puppy to have a necropsy.
There are many causes for the loss of a near term or newly-born litter of puppies: coronavirus, parvovirus, toxoplasmosis, brucellosis, umbilical trauma, genetic disease, etc. Knowing what to do heavily depends on knowing what happened. Puppies who die from canine herpes have characteristic inclusion bodies in many tissues under the microscope. Inclusion bodies are essentially areas of heavy virus reproduction that are visible and unique in appearance. The presence of herpes inclusion bodies confirms the diagnosis.
The ability of an infected dog to maintain antibodies against canine herpes is variable. Some infected dogs show no antibodies after a couple of months and others have antibody levels persisting for years. If the history is suggestive of herpes, then any herpes antibodies found in the bloodstream would be considered significant. Without the history of puppy loss, antibodies simply indicate past exposure to the virus.
To get a better sense of how acute an exposure might be and whether or not the antibody level indicates active infection, a second antibody level can be drawn 10 to 14 days later. An active infection will show a four-fold rise in antibody level. In a breeding kennel situation, it may be useful to know which dogs have been exposed and which have not so that the risks can be assessed. It is only the unexposed females that are at risk for infection during pregnancy and losing the litter. Checking titers before breeding is not a bad idea for both the male and female dog.
If the infection is less than 3 weeks old, it may be possible to actually culture the virus from swabs from the nose or vagina. In general, confirming herpes infection in a dead puppy is much easier and faster than trying to confirm the infection in the adult dog.
Recently a PCR test (a test for herpesviral DNA) has been developed for dogs. This test is likely to become the diagnostic test of choice.
Canine herpes is very bad news for puppies under age 3 weeks of age. Often there is nothing that can be done to stop the sweep of this lethal virus. This does not keep us from fighting, however. Serum from a recovered dog can be separated and injected into the puppies as a source of anti-herpes antibodies. Warming the puppies may help as the virus cannot survive at body temperature. Antiviral medications such as Acyclovir may help.
Fortunately, herpesviruses do not live in the environment (they die at 68º F and are readily killed by common disinfectants). Direct contact with an infected host or fresh secretions is needed for transmission. Still, once a dog is infected, she will be infected for life. Shedding virus is increased by stress.
One more time: all mother dogs should be isolated from the final 3 weeks of pregnancy through the first 3 weeks after birth. In Europe, a vaccine is available for use during canine pregnancy (one dose at the time of breeding and a second 6 to 7 weeks later, to be repeated with each pregnancy).
Herpes is only a danger to the puppies when the mother is infected during pregnancy or shortly after delivery. Once the mother has been infected, subsequent pregnancies should be unaffected as she will have made enough antibodies to keep the virus in check.
- Canine herpes only causes symptoms in unborn or newborn puppies and they usually do not survive infection.
- The mother dog will not appear sick.
- Problems only occur for the puppies when an uninfected female becomes infected during pregnancy. Females infected long before pregnancy do not lose their litters to herpes.
- Herpes is a common canine infection and is spread not only by sexual contact but via oral and nasal secretions.
Reference: The Pet Health Library, Wendy C. Brooks, DVM, DipABVP, Educational Director, VeterinaryPartner.com