An investigation was carried out on 244 rats (71,9% sewer rat; 27,7% black rats, 0,4% house mouse) with various index 30-40, which was increased and kept at high level from March to September. 268 fleas were collected (only 1 species of X.cheopis), the flea index oscillated from 0,11 to 1,90 and reached the highest level in April all isolations determined Y.pestis negatively. Flea resisted to malathion 5%, pyrethroid group was the greatest effectiveness
Plague ; Fleas

Backgound: Plague disease is one of three most seriously infectious diseases (plague, yellow fever and cholera disease). In Vietnam, this condition has been obviously controlled. The number of new cases and deaths of plague disease have decreased significantly: from 439.6 patients between 1991 and 1995 to 161.2 patients between 1996 and 2000. However, the disease is still circulating in some areas in the world. Objective: To survey plague disease related factors (rats and fleas) at Noi Bai international airport. Subjects and method: A surveillance to inspect plague disease related factors (rats and fleas) was conducted at Noi Bai international airport, Ha Noi, from January/2006 to December/2006. Results and Conclusion: There were two types of rats: R. flavipectus in majority and R. norvegicus. The enrichment index of the two kinds of rats had increased in April and May. R. flavipectus disposed at flat form T1 and R. norvegicus disposed at store area. The only flea species found at the surveillance site was X.cheopis. Bacterial isolation of 236 specimens of liver and spleen, and ELISA tests of 180 blood samples were performed. All of the specimens were negative to Yersinia pestis. The study suggests that the rat populations at Noi Bai airport have not been infected with Yesinia pestis.
Plague/ epidemiology ; pathology ; Siphonaptera/ pathogenicity ; Rats ;