The 400 hydatid egg count per gram found in fecal matter was done by CDC and WHO infectious disease mds in hydatid contaminated epidemic regions where they tested human and animal fecal matter under a microscope and did egg counts. 400 eggs per gram (about a teaspoon) is the average egg count shed in a hydatid or e.granulosus infected human or animal.
The biggest problem with medical or animal dewormers is if the parasite load is behind the eyes it can cause optical damage during die off, also complications can occur if a huge load of worms obstruct or block the alimentary canal during die off and elimination. That is why some people with filarial (threadworm) parasites behind the eyes or a really heavy parasite load, like a bad ascarus or Tapeworm infection are recommended to take the medicines in treatment in a hospital for a few days, just in case. In parasite infected regions in Africa, Bill Gates and ex pres Jimmy Carter's health comission just pass out 650 milligram doses to 1 gram dose of praziquantel to all the infected villagers as there are no facilities in many hydatid endemic regions. WHO and CDC, global health comissions mds reported a 97% cure rate, 8 and 16 weeks later when fecal egg counts were done after single dose treatment of praziquantel. Problems cited in the WHO md drafted report was 400 million doses was not enough as there are hundreds of millions affected and are dying and in need of seasonal dosages due to reinfection from lack of santation systems. Bayer drug company said it can not afford to make another 400 million single dosages of praziquantel to be sold at cost again.
I personally think slowly reducing the parasite load is best. With ongoing correct diet, a clean colon, good elimination, herb and spice dewormers, a strong clean liver, liver flushes, good hygiene and an ongoing anti parasite program you will be reducing the load so if stronger medicines are used the die off will be easier to manage and eliminate.