I came across an interesting (and somewhat bizarre) paper in the journal The Lancet from 1988. It described a case of listeriosis in a baby. Listeriosis is caused by the bacterium Listeria monocytogenes. Human infections are usually acquired from eating contaminated food. I made some comments about the risk of listeriosis to household pets in an earlier post during the recent foodborne outbreak of listeriosis in Canada that was associated with contaminated meat
The paper from 1988 puts a "new spin" on potential sources of infection for pets.
The baby described in the report was not breastfed for the first three days of life because her mother had some post-delivery complications. The surplus milk that was collected over those three days was reportedly fed to a litter of Doberman puppies. All three puppies in the litter became sick the day after the child began showing signs of illness. Listeriosis was diagnosed in both the baby and the puppies. Listeria monocytogenes was cultured from the mother’s milk. Apparently the baby and the puppies were all infected by drinking the mother’s milk. The baby, and two of the three puppies, survived.
Certainly, human-associated listeriosis in pets is extremely rare, and (presumably) so is feeding puppies human milk. This case just shows how infectious diseases can do strange things, and that diseases can move between people and animals in both directions. It also highlights that knowing the health status of both animals and people is important for physicians and veterinarians to make informed decisions about diagnosis and treatment of some diseases.