Khin Maung TinE, UKyaw ThetThant Zin2009-06-302009-06-301969-01-011969-01-01Khin Maung Tin, E, U, Kyaw Thet, Thant Zin. The clinical and epidemiological observations on viral hepatitis in the Rangoon General Hospital. Union of Burma Journal of Life Scieces. 1969; 2(1): 53-58http://imsear.searo.who.int/handle/123456789/126668Periodic assessments on the susceptibility level of some anopheline vectors were carried out at routine catching stations in Kyaukse, Myingyan and Bassein Districts from 1958 up to date. The results obtained indicated that the increase of DDT pressure created bgy prolonged annual application of DDT reduced the susceptibility level of A.culicifacies and developed increased tolerance to DDT. But this species was found to be highly susceptible to dieldrin. Subsequently, the results taken in 1957 revealed that A. culicifacies in Kyaukse area was found to be resistant to DDT. A. sundaicus in a Pyinkhayaing village, Bassein, was still found to be highly susceptible to DDT up to date. The slope, shape and position of regression lines are meaningful in interpreting the changes in the response of mosquitoes to insecticide due to vigour tolerance or physiological resistance. LC50 values may remain close to base-line value in partially resistant heterogeneous strains. But only when resistant individuals approach 40 percent to 50 percent in the whole population, dose the LC50 value of the strain rise noticeably.Hepatitis Viral, Human-epidemiologyMyanmar