The wireless network is essential for medical solutions due to its accessibility for healthcare professionals by reducing costs. Hence it is essential to secure the network against attacks most importantly flooding attack that makes the entire network to degrade. In Mobile Ad-hoc Networks (MANET), each and every node act as transmitter and receiver and are assumed working with co-operative nature. Watchdog is a renowned method to detect and prevent the selfish nodes. In this work, we have tried to improve the energy efficiency at the node level and to increase the network lifetime by proposing model called CoCoWa based on diffusion of selfish nodes when a contact occurs, so that information is quickly propagated. The experimental works are carried over by network simulator. The experimental results and analyses for reducing the overhead and improved other metrics such as delay and throughput. © 2017 IEEE.