The flu has been identified as H1N1, the descendants of the 2009 pandemic virus.
I wonder if this area is remote enough not to be affected by seasonal flu most years, due to lack of contact, and perhaps large numbers of people had never been exposed to this virus or its relatives? Alternatively, perhaps the severe cases in young children reflect people who were not yet alive at the time of the pandemic and so had no existing immunity to H1 viruses?
Obviously, malnutrition doesn't help, but there might be immunological factors that explain why the illness here was more severe than expected.
If the cold chain can be preserved, perhaps the seasonal flu shot, which contains this virus, should be deployed to the affected area. If not, Tamiflu pills, which are shelf stable and don't require refrigeration (and are relatively cheap), should be administered to cases with respiratory symptoms. Even 15 years post-pandemic, most H1N1 viruses are Tamiflu sensitive.