Puppies that die at 2 days of age due to larval nematodes in their lungs are most likely due to which parasite?

The scenario describes a situation where puppies die at a very young age, specifically due to larval nematodes in their lungs. Toxocara canis, the roundworm, is highly relevant in this context. This parasite can be transmitted from mother to puppies either through transplacental or transmammary routes, leading to significant infections particularly in very young animals. The larvae can migrate through various tissues, including the lungs, which is a critical aspect when considering the cause of respiratory distress and subsequent death in newborns.

In this case, the presence of the larvae in the lungs is significant because as they migrate, they can cause severe respiratory issues leading to the death of puppies shortly after birth. It is important to note that while other parasites like Ancylostoma caninum (hookworm) can cause serious health problems and potentially lead to death, they typically have a different lifecyle and may not directly result in immediate fatalities at 2 days of age through the mechanism described. Giardia lamblia is a protozoan that primarily affects the gastrointestinal tract and is not typically associated with lung migration or death in such young animals. Similarly, Trichuris vulpis (whipworm) primarily affects older puppies and adult dogs through intestinal issues and