222 SCHROEDER 



mongoose, genet and horse. We can use almost the same order for animals 

 other than man, except that the vampire bat would hold first or second 

 position. Practical methods for the control of migration of the domestic 

 dog are available, but they are not and will not be followed in the U. S. A. 

 If the dog were declared legally a domestic animal, the Department of 

 Agriculture could set up a vigorous government supervised program for 

 the control of traffic and migration of dogs which would quickly bring 

 an end to our dog-transmitted rabies problem. For many unrelated rea- 

 sons, dog owners and kennel clubs are not in accord w^ith this proposal. 

 Bats, however, present quite a different problem and there are no simple 

 methods for either area extermination or migration prevention. 



In July, 1950, the author had occasion to investigate serious cattle 

 losses in an agricultural area in and adjacent to La Ceiba, Honduras. The 

 losses far exceeded those usually caused by snake bite, chronic infectious 

 diseases and nutritional inadequacies. The successful management of ex- 

 tensive banana plantations — the property of the Standard Fruit Company 

 of New Orleans — was dependent on the maintenance of adequate sources 

 of milk and other dairy products and meat for the field workers. Cattle 

 losses therefore seriously interfered with banana production. The causes 

 of death were variously attributed to metal poisoning, plant spray poison- 

 ing, tick fever, anaplasmosis, pasteurellosis, brucellosis, listeriosis, bovine 

 encephalitis, infectious bulbar paralysis (Aujesky's disease), and botulism. 

 Brain tissue had been sent to the Virus and Rickettsial Laboratories of 

 the Communicable Disease Center, Montgomery, Alabama, and rabies 

 virus had been isolated. The author discussed these findings with Harold 

 Johnson at the Rockefeller Institute for Medical Research, New York 

 City, preliminary to making the field investigation, and it was tentatively 

 agreed that the cause of death might very well be "Derriengue" — vam- 

 pire bat-transmitted paralytic rabies. Ten animals were examined within 

 a five day period, July 13-18, 1950, at La Ceiba. Brain tissues from six 

 of seven specimens were positive for inclusion bodies from direct impres- 

 sions of Ammon's horn using Seller's stain, and proved to be positive by 

 mouse inoculation. Postmortem changes were too far advanced to use 

 tissues from three other cases. Vampire bats identified as Desmodus 

 rotundus murinus, Wagner, were present in large numbers in the area, 

 retreating to hollow Ceiba trees, old buildings, and palm trees during 

 the daylight hours. Of fifty bat brains collected in neutral glycerine, all 

 were negative on mouse inoculation. However, cattle losses were most 

 abundant where the bat population was greatest, especially along the 

 river courses. Potential virus sources, other than bats, were not apparent. 

 By animal inoculation and by serological and cultural means, other in- 



