I read this book hastily a few years back and wish to re-read it, slowly this time. The theme is that of an infinite universe in which earth is replicated infinite times and we here on this earth have developed the means to connect with other earths. The title was "Black*** Mountain" or similar. Every earth contacted in the institute inside this mountain is being ravaged by a zombie type plague and it transpires the plague is purposely being let loose on each earth by a religious cult centred on one such earth.
I hope someone can relate the title and/or author of this fine SF book.