Bill Gates of Bill and Melinda Gates foundation has congratulated Bihar Chief Minister for the state having no report of wild poliovirus in Bihar during the past 16 months.

"On the occasion of India being free of polio for one year, it is truly a pleasure to congratulate you on more than 16 months without a reported case of wild poliovirus in Bihar", Gates said in a letter to Nitish Kumar which was made available to the media today.

"When I first visited Bihar's polio programme in 2010, I was struck by the sheer scale of the effort and by your administration's keen ability to work synergistically with the World Health Organiszation, UNICEF, Rotary International and your local polio partners to reach some of the most remote and high-risk regions in Bihar. Even activities in the Kosi River region, which undoubtedly present some of the most challenging conditions faced by the global polio programme, were robust," he lauded.

"Your personal leadership has been extraordinary and your administration deserves special credit for this accomplishment. We hope your example inspires other governments around the world to strive for similar successes in this truly global effort", Bill Gates in his letter said.

"As you are aware, it is now more important than ever to sustain this remarkable progress. Despite the absence of reported polio cases in Bihar since September 2010, the risk of wild poliovirus importation through migrant groups and in high-risk areas continues to be very real. Your continued personal supervision of polio vaccination and surveillance efforts is critical and I would urge you to maintain regular communication with high-risk districts, particularly in the Kosi region to understand and directly address critical challenges," he said in his letter to the Chief Minister.