Finding out how scavengers survive eating spoiled meat could save people

Scavengers are subject to endless infections due to their diet of decayed organic matter. Various studies have tried to explain how these species avoid disease. No one has been able to discover this with certainty. Despite this, the scientific community assures that a detailed understanding of the mechanisms of immunological defense of these living creatures could improve medicine and human health.

Researchers from around the world have come up with many theories trying to explain how some animals can eat carrion. A study led by Daniel Blumstein, an ecologist at the University of California, Los Angeles (UCLA), analyzed eight hypotheses put forward over the past few decades. The goal was to evaluate the validity and strength of its foundations.

Studying scavengers could save people

The revised hypotheses provide different explanations. Work published in 1975 suggests that vultures eat at a high rate to prevent the formation of bacterial spores. Another study published in 2009 indicates that these birds urinate on their feet before eating to kill pathogens. Another suggests that the hair loss characteristic of some of these species is a physiological modification that facilitates cleaning and reduces exposure to viruses. In turn, a 2015 study qualifies raccoons’ food-washing behavior as a method of defense.

Blumstein and his colleagues rejected these approaches. “We found no strong evidence that using urine to sterilize carcasses, going bald, eating fast, or washing food reduces the risk of disease in scavengers,” they explain. On the contrary, they explain that the most robust claim suggests the existence of an enhanced immune system in scavengers. These include physical barriers such as the skin and immune surveillance devices such as natural killer cells and phagocytic leukocytes (WBCs).

Seven of the studies reviewed assessed hypothetical immune processes in mammals, birds, and reptiles. They agree that vultures have a more developed innate immune system compared to their relatives, who prefer fresh food. Experts note that maintaining a low stomach pH, ​​avoiding foods that take days to decompose, and having a specialized microbiome and optimized immune defenses are the theories that most closely justify how scavengers survive in their diet. However, the authors note that the available data is insufficient to determine a single strategy. “The limited amount of research tells us that we need more research to really understand how they do this,” Blumstein adds.

A specialist from the University of California at Los Angeles emphasizes that accelerating research on the topic could lead to the discovery of new alternatives to fight infections in humans and counteract drug resistance.

Today, resistant bacteria kill more than a million people a year. New project research Global research on antimicrobial resistance (GRAM) shows that without changes in disease prevention and the search for new antibiotics, deaths caused by thesesuperbugscould approach 2 million per year in 2050.

“Antibiotic resistance poses a huge threat to global public health. Scavengers can spread pathogens over long distances in search of their next meal. From a biomimetic point of view, some of their defense mechanisms could potentially be used to improve human and veterinary medicine,” concludes Blumstein.