Double Damned: English Tuberculosis Complex (2018) provided a history of errors in the attempted eradication of bovine tuberculosis (bTB) from the UK. Covid-19 appeared in 2019 and illustrated that the errors were embedded in the human race. Homo stupidus contains an update of the book, and much more. Human stupidity has and continues to hamper control and eradication of disease. For example, bTB is spread by movement of infected cattle and badgers. Incest is very rare in mammals. Male badgers move outside their social group to breed, and inadvertently spread disease.This long-established fact was ignored by planners. Badger bTB was localised to the West Country for at least 20 years, but is now widespread nationally. Badger to cattle and cattle to badger transmission occurs: once introduced, the major spread is within species. The disease was eradicated years ago from countries where it had not established in wild life.Aspects of the disease have changed during the past 50 years, but a possible solution is suggested. Simple fatal errors made in the control/eradication of Covid-19 are specified and discussed. Human and animal disease control/eradication is confounded by ignorance, misunderstanding, polarised viewpoints, fragments of information, conflicting ethics, political expediency and complex mathematics.