New Tests to Diagnose Chlamydia in Livestock

New tests to diagnose Chlamydia in livestock--and accurately identify all known strains of the bacterium--have been developed by scientists with the Agricultural Research Service in Ames, Iowa.

More than 60 chlamydial strains infect birds and mammals, including humans. In humans, Chlamydia causes sexually transmitted diseases, respiratory disease and eye infection leading to blindness. Recently, it has been associated with coronary atherosclerosis. In animals, Chlamydia causes respiratory disease, conjunctivitis, arthritis, enteritis and reproductive failure. In birds, chlamydial infection results in lethargy and sometimes death.

Until now, researchers studying these bacteria had to grow them in cell culture or in fertilized chicken eggs to confirm their presence. The new tests use polymerase chain reaction (PCR) to target DNA genetic material found in all chlamydial strains.

The new tests will help veterinarians diagnose and improve treatment for sick birds and animals. Most important, they will shed light on how people and animals become infected. The lone DNA-based test now available detects only some chlamydial strains that infect humans.

The new Chlamydia tests take about four hours, compared to two to four days to isolate the organism in tissue culture. ARS has applied for a patent on the new tests.

An article about the Chlamydia tests and research appears in the June issue of Agricultural Research magazine. The article is also on the World Wide Web at:

http://www.ars.usda.gov/is/AR/archive/jun98/test0698.htm

Scientific contact: Arthur A. Andersen, ARS Avian and Swine Respiratory Diseases Research Unit, National Animal Disease Center, Ames, IA 50010, phone (515) 239-8338, fax (515) 239-8458, aanderse@nadc.ars.usda.gov.