TOXOPLASMOSIS: ABORTIONS, WEAK KIDS, STILLBIRTHS

Toxoplasmosis is a disease that causes abortions, weak kids, stillbirths, birth defects, and mummification of fetuses in pregnant does. Cats are the carriers of this protozoan known as Toxoplasma gondii. Cats, especially kittens under six months of age, pass the oocysts in their feces when they eat infected rodents, raw meat, or placentas of toxoplasmosis-infected animals.

Goats become infected with this parasite when they eat grain, grass, or hay that has been contaminated by cat feces. The infection enters the body through the small intestine and nearby lymph nodes, then spreads throughout the goat's system via the blood stream. Toxoplasma gondii can be encysted for years in the goat's brain, muscles, liver, or other vital organs. Some resistance to future infection (immunity) is usually acquired by previously-infected does. Male goats can be carriers. Weak kids born of Toxoplasmosis-positive does require extensive supportive care in order to survive.

Toxoplasmosis-caused abortions usually (but not always) occur during the first half of gestation. Once the pregnant doe has been infected, it takes about two weeks for the parasite to infiltrate the placenta and kill the fetuses. Blood tests can be done on does immediately after they have aborted, but because a doe can test 'positive' for Toxoplasmosis for years after becoming infected, it is easier to prove that the cause was not this protozoan by obtaining a 'negative' serological (blood) reading. It is reasonable to conclude that any doe testing positive for Toxoplasmosis as long as six months after she has aborted is still highly infected with the disease and therefore is a threat to the other animals in the herd.

Aborted placentas can be tested, but getting accurate results can be difficult. The longer the doe was infected before she aborted, the easier it is to determine if Toxoplasmosis was the cause. Because most producers have no idea when the actual infection took place, placental testing is less helpful than blood testing. A fetal blood test is available but works best during the last half of the pregnancy. If the fetus is infected when quite young, antibodies may not appear in the blood but it could still be harboring Toxoplasmosis. Many producers will not find it cost-effective to do in utero blood testing.

At the present time in the United States of America, there is neither a vaccine nor a cure for this disease, and there is no regimen of medication effective against Toxoplasmosis. There is a Toxoplasmosis vaccine available for use with sheep in Britain, but it is a live vaccine that also infects humans. The likelihood of its ever being approved for usage in the USA is low. No testing has been done to determine if it might be effective against Toxoplasmosis in goats.

Ed Lehigh, Vice President-Marketing, Colorado Serum Company, says that research for and production of a vaccine to prevent Toxoplasmosis in goats, sheep, or cattle is not likely to occur at any time in the foreseeable future. The cost of establishing a laboratory in which to begin the research would exceed a million dollars, according to Mr. Lehigh. Vaccine manufacturers do not see a large enough market for the resulting product to justify the investment.

Prevention involves keeping feed (grain and hay) away from cat feces. Clean bedding and pen areas are essential. Barn cats are useful, but the population must be kept under control. Kittens are more likely to be carriers than adult cats, and it is possible that only one cat is the host. Neuter/spay all adult cats, and do not feed them raw meat. A blood test is available for cats to determine if they carry Toxoplasmosis antibodies. Keep the rodent population down with carefully-placed containers of rat bait. Do not depend upon cats to keep the rat population down; such action will likely compound your potential of introducing Toxoplasmosis to your goats, your cats, and even your family. Toxoplasmosis is zoonotic . . . it can be transmitted to humans. Pregnant human females should never be exposed to Toxoplasmosis because fetal abortion and/or serious birth defects are possible. Using disposable gloves and proper containers, burn or otherwise permanently get rid of all placental material, dead fetuses, and anything else that has come in contact with the infection. Because the milk of a Toxoplasmosis-positive doe can be infected, pasteurization is essential prior to consumption. Either thoroughly cook all meat or dispose of the carcass properly. Bob Glass of Pan American Vet Laboratory in Austin, Texas advises that the meat-encysted parasite can be very difficult to eliminate.

Blood testing for this disease in goats, cats, sheep, and cattle is available through Pan American Vet Laboratory. Their toll-free phone number is 1-800-856-9655.

The author thanks Ed Lehigh of Colorado Serum Company and Bob Glass of Pan American Veterinary Laboratory for their contributions to this article.

The author, Suzanne Gasparotto, hereby grants to local goat publications and club newsletters, permission to reprint articles published on the Onion Creek Ranch website under these conditions: THE ARTICLE MUST BE REPRODUCED IN ITS ENTIRETY AND THE AUTHOR'S NAME, ADDRESS, AND CONTACT INFORMATION MUST BE INCLUDED AT THE BEGINNING OF THE REPRINT. We would appreciate notification from any clubs or publications when the articles are used. (A copy of the newsletter or publication would also be a welcome addition to our growing library of goat related information!)

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