A fulminating extension of rabies-which has been enzootic in northern Malaya since 1924-occurred in Kuala Lumpur in April 1952. The outbreak was suppressed by the compulsory mass vaccination of dogs, stringent legislation, and intensive stray-dog destruction. Similar measures are being employed in the current campaign, the aim of which is the complete eradication of the disease.From an average annual incidence of 112 confirmed canine cases prior to 1952-when a total of 198 cases was reported-the incidence fell to 15 cases (all in unvaccinated dogs) for the period January-November 1953, during the last 5(1/2) months of which no case in either animals or man was reported. It is considered that the extensive publicity campaign and strict enforcement of the control measures have contributed measurably to the present improved position.Statistics relating to confirmed cases in dogs previously vaccinated with (a) phenolized 20% brain-tissue suspension vaccine (buffalo origin) and (b) chicken-embryo vaccine (Flury strain) are quoted and their probable significance in favour of the latter under Malayan conditions is discussed. The hypothesis that the development of rabies may, in many instances, have been blocked by the vaccine is advanced.The plan for a pan-Federation compulsory vaccination campaign in 1954, to consolidate the 1952-3 improvements, is outlined.
In previous papers it has been demonstrated that ground-dwelling rats are the principal reservoir of leptospirosis in Malaya. The present paper considers the distribution of infection by sex and weight in the ten principal rat species. There appears to be a general tendency for females to be infected more frequently than males, but significant differences were demonstrated only in R. sabanus (more than three times as many females as males infected) and R. whiteheadi. In Malaya, where seasonal changes are minimal, weights can be used as a good index of age in rats. In rat species with a low incidence of infection the incidence appeared to rise steadily with age. In species with a medium incidence the infection rate rose at first with age, fell in the 6-8-month age-group, and then rose again. In high-incidence species the rate rose rapidly from the second month.There appear to be three types of enzootic infection; (1) intensive transmission of a single serogroup in a crowded population of rats of a single species (transmission probably being through urinary contamination of damp soil); (2) low-intensity transmission of several serogroups among ground-rats frequenting wet places (probably with urinary transmission); and (3) low-intensity transmission of several serogroups among ground-rats in dry places (the transmission may be venereal).