<prompt> The most sensitive index for surveillance of malaria transmission is -Spleen rateParasite density indexInfant parasite ratePropoional case rate  <response>: - infant parasite rate is defined as the percentage of infants below the age of one year showing malaria parasites in their blood films. - It is regarded as the most sensitive index of transmission of malaria in a locality. Reference : Parks textbook of preventive and social medicine, 23rd edition pg no: 261 p 