Animal leptospirosis in Malaya: 3. Incidence in rats by sex, weight and age

摘要: Abstract In previous papers it has been demonstrated that ground-dwelling rats are the principal reservoir of leptospirosis in Malaya. The present paper considers distribution infection by sex and weight ten rat species. There appears to be a general tendency for females infected more frequently than males, but significant differences were only R. sabanus (more three times as many males infected) whiteheadi. In Malaya, where seasonal changes minimal, weights can used good index age rats. species with low incidence appeared rise steadily age. medium rate rose at first age, fell 6-8-month age-group, then again. high-incidence rapidly from second month. There appear types enzootic infection; (1) intensive transmission single serogroup crowded population (transmission probably being through urinary contamination damp soil); (2) low-intensity several serogroups among ground-rats frequenting wet places (probably transmission); (3) dry (the may venereal).