Blood-borne infections in young puppies are caused by bacteria that gain entrance via the respiratory and gastrointestinal tracts. They occur in puppies 5 to 12 weeks of age. At this age maternal antibodies are in decline and immunity acquired through vaccinations is not as strong as it eventually will be. This creates a window of vulnerability.
Very important contributing factors include overcrowding, chilling, poor nutrition, unsanitary whelping quarters, a heavy burden of intestinal parasites, and coexistent viral infections. In a healthy environment, bacterial exposure usually produces only a mild, self-limiting illness. But when environmental stresses are added, the death rate is high.
Signs of respiratory involvement include fever, cough, nasal discharge, and rapid, noisy breathing. When the gastrointestinal tract is involved, signs include loss of appetite, vomiting, diarrhea, weakness, dehydration, and weight loss.
Treatment: Notify your veterinarian if a puppy shows any of the signs just described. Shock and dehydration are treated with antibiotics and intravenous fluids. Respiratory and GI tract infections are treated like Pneumonia and Acute Infectious Enteritis.