Which of the following is commonly recognized as a contributing factor in the emergence of transboundary diseases?

Increased global travel is indeed a commonly recognized contributing factor in the emergence of transboundary diseases. This is due to the facilitation of animal and pathogen movement across regions and borders, which can lead to the spread of diseases to new populations. Global travel enables not only the movement of livestock but also the potential for infected animals or their products to reach new areas, increasing the risk of introducing diseases that were previously geographically confined.

In contrast, strict quarantine measures serve to control and prevent the spread of diseases by restricting the movement of animals and animal products from affected areas. Similarly, restricted wildlife trade aims to limit the interaction and transmission of diseases between wild and domestic animals, thereby reducing the risk of disease emergence. Lower animal population densities can also have an impact by potentially reducing the likelihood of disease spread, as diseases are often more easily transmitted in densely populated animal groups. Thus, while all other options involve measures or conditions that typically work against the emergence of diseases, increased global travel actively contributes to the risk of transboundary disease outbreaks.