Preliminary Studies Of DNA Vaccines Against Legionella Pneumophila

Legionellosis is a serious and sometimes fatal form of pneumonia. It is caused by the bacterium Legionella pneumophila and other legionella species,such as L. bozemanii and L. dumoffii, and the species L.micdadei. The legionellae have been found in natural freshwater systems and man-made aquatic environments. Legionella pneumophila infection follows the inhalation of aerosols generated by L.pneumophila-contaminated water sources,and caused disease such as untypical pneumonia and Pontiac fever. The death rate as a result of legionnella is dependent on the appropriateness of initial anti-microbial treatment. Case fatality rate may be very high in untreated immuno-suppressed patients. The elderly and immunocompromised individuals are the susceptible host.Currently, there are 48 species comprising 70 distinct serogroups in the genus Legionella. Although there are now 15 serogroups of Legionella pneumophila, 79%of all confirmed cases are caused by Legionella pneumophila serogroup 1. Legionella pneumophila causes approximately 90% of all reported cases of legionellosis in the United States. With the popularity of air-condition and humidifier in modern life, Legionella infection will increase and could be outbreak in someday if control and prevention measures are unavailable. There is no vaccine currently available for Legionnaires' disease.China and many other countries have classified it as a new emerging infectious disease that must be prevented and controlled.But there is no satisfactory prevention and control measures, and therefore develope some safe and effective vaccines for the disease will be of practical significance.