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Development of a Loop-Mediated Isothermal Amplification Method for Rapid Diagnosis of Avian and Animal Chlamydiosis

Principal Investigator/Project Leader: 
Department of Project: 
Microbiology Dept.
Project Description: 

Chlamydiae are implicated in a variety of clinically and economically important diseases in livestock and companion animals. These bacteria are associated with abortion, conjunctivitis, encephalomyelitis, enteritis, pneumonia, and polyarthritis in ruminants. Infection with these bacteria is the most common cause of abortion in sheep and goats and also causes zoonotic infection in humans which, in pregnant women, can result in spontaneous abortion. Infection in cattle significantly reduces performance in fertility, neonatal growth and causes mastitis; the three most important areas of bovine production. Bovine infertility and abortion have been recognized as an increasing problem and losses to the cattle industry have been substantial. Infected bulls often display inflammation of the seminal vesicules and may transmit chlamydiae to cows as a venereal disease, where they can replicate, possibly leading to embryonic death.

Chlamydiosis bacteria also cause psittacosis and is one of the most common bacterial infections in our pet bird population. Infected pet birds, usually cockatiels, parakeets, parrots, and macaws as well as domestic poultry are the most affected in the United States. There have been several outbreaks of psittacosis nationally starting at pet shops or poultry factories and the infection can be transmitted to humans resulting in a sometimes fatal respiratory disease.

Establishing a timely confirmatory diagnosis of chlamydial infection in affected poultry and livestock is difficult as there is no single test to accurately diagnose the disease. Conventional diagnostic methods have inherent problems in detection and interpretation of results. Loop-mediated isothermal amplification (LAMP) is a novel DNA amplification method that is highly specific, efficient, and fast under isothermal conditions. The reaction can be processed at a constant temperature (~60C) and the specificity and detection limit have been shown to be comparable to polymerase chain reaction (current gold standard for detection of organisms, but is highly technical and expensive). These assays can be rapid (30-60 min) and results can be read visually without the need for expensive equipment and technical expertise. This project will explore the hypothesis that development of an effective LAMP assay for livestock and avian chlamydiosis will lead to significant reductions in zoonotic disease as well as morbidity, mortality and the reproductive health of farm animals.

Upon successful completion, this project will positively impact the citizens of Massachusetts and the nation by 1) establishing for the first time a standardized, easy to use testing system for chlamydiosis thus improving, ovine, caprine, camelid and bovine herd health; both of beef and dairy cattle; 2) enhancing milk production and quality, through reduced mastitis; 3) better fertility of both beef and dairy cattle, and improved growth rates of neonatal animals; 4) significantly reducing the rates of psittacosis and zoonotic chlamydiae infections and 5) provide much needed epidemiological data on the prevalence of chlamydiosis nationally.