Blog Post 2 (Week 3) - New Fatal Bacterial Disease in Chimpanzees

Chimpanzees at the Tacugama Sanctuary

For my second week, I will be investigating a FOX News article by Julia Musto, titled "Researchers worry chimpanzee-killing bacterium could jump to humans next." I will attempt to determine whether science was misused in the article as it instigates the concern that chimpanzee diseases can affect humans.

Summary of Article:

According to the news article, scientists are concerned about a recent bacterial disease that has been infecting chimpanzees at the Tacugama Chimpanzee Sanctuary (TCS) in Sierra Leone. Referencing a scientific article that was published on February 3rd in Nature Communications, the article discusses how the disease has killed 56 chimpanzees between 2005 and 2018 and has, so far, had a 100% mortality rate. The bacterium that is believed to be the cause of the disease has been named Sarcina troglodytae (after the chimpanzee species it infects - Pan troglodytes). The disease has been named Epizootic Neurologic and Gastroenteric Syndrome (ENGS), and is associated with severe diarrhea, vomiting and nausea. The greatest concern for scientists, according to the article, is that the disease may spread to humans. Gut bacteria in both chimpanzees and humans, is "nearly identical," and humans and chimpanzees have genomes that are 99% similar (here they link another news article from November 2012 to back up this claim). "There are very few pathogens that infect chimpanzees without infecting humans and very few pathogens that infect humans without infecting chimpanzees," lead researcher Tony Goldberg has stated.

Science in the Article:

This news article is categorized in the science section on the FOX News website. The title originally had "virus" in place of "bacterium" (refer to comments), although that has since been corrected. It appears that the news article is meant to draw concerns about the possibility that what appears to be a deadly bacterial disease in chimpanzees has a high likelihood of passing to humans. The scientific article they are referring to, however, titled "A Sarcina bacterium linked to lethal disease in sanctuary chimpanzees in Sierra Leone," focuses mainly on analyzing a particular new bacterial strain they found in the select chimpanzee population found in TCS, and being able to draw comparisons between similar Sarcina infections that affect humans. The authors mention in their discussion that "the genetic and physiological similarities between humans and chimpanzees are often cited as predisposing them to cross-species pathogen exchange" (Owens et. al). Yet, they have seen that in over 10 years of illness in the TCS chimpanzees (2005-2018), no known human cases have been reported, "even among personnel with close daily contact with affected individuals" (Owens et. al). 

While the scientific journal they cited does not explicitly say (and seems almost to even suggest the opposite) that scientists are particularly concerned about the disease hopping to humans, FOX suggests that because human and chimpanzee gut bacteria are "nearly identical," this poses the greater likelihood that this fatal bacterial disease can jump to humans. The article they referenced for this claim, "Chimpanzees and humans harbor compositionally similar gut enterotypes," discusses the similarities between human and chimpanzee 'enterotypes,' which are characteristic community structures in the gut. They found that the two species' enterotypes are "compositionally analogous," supporting the evolutionary relationship between chimpanzees and humans and the presence of similar enterotypes in their common ancestor. However, they do not indicate anywhere in the article that human and chimpanzee gut bacteria are "nearly identical." They do write, however, that "because enterotypes represent divisions within a continuous character (that is, the relative frequencies of numerous bacterial taxa within hosts), hosts that have the same enterotype need not have identical microbial communities" (Moeller et. al).

While this news article may have made some extrapolations from the scientific articles they have referenced in the article, it does appear to be correct in suggesting that an organism's individual gut bacteria plays a role in its susceptibility to bacterial infections. According to the scientific review article, "The gut microbiome: Relationships with disease and opportunities for therapy,"quite a bit of research has been done on the role of human gut microbes have in immune function. The authors have found that there is "increasing evidence for microbial causality in disease development and identification of specific mechanisms of pathogenesis" (Durack and Lynch). IF it was the case that the new bacterial disease in the TCS chimpanzees spread to humans and IF the human and chimpanzee gut bacteria are "nearly identical," then it is reasonable to be concerned that the spread of this new disease to humans can be just as fatal and dangerous as it is currently in the TCS chimpanzee population.

Assessment: Was Science Misused?

The FOX news article draws much concern that a new fatal bacterial disease in chimpanzees can spread to humans. Yet the scientific article they cited makes it clear that this was not a main concern of their study, even stating that there are no known cases (even among personnel who are directly in contact with sick chimpanzees) of the bacterial disease in humans, although the disease is being monitored by lead researcher Tony Goldberg to see if that is a possibility (even there, the main concern is more so that the disease could spread to wild chimpanzees, not humans). Furthermore, the article's claim that human and chimpanzee gut bacteria are "nearly identical" also appears to be extrapolated from the scientific article that found that chimpanzees and humans have similar enterotypes, which is certainly not the same thing as saying their gut bacteria are "identical." For these reasons, I find that the article misuses, or at least, misrepresents, the science to overstate concerns over a new fatal disease potentially spreading to humans. While there is much scientific evidence that says that gut microbiomes have major influences on an individual's immunity, the news article's claims that human and chimpanzee's gut microbiota are nearly identical is not true, and the fact that no humans have been infected by the disease suggests that the new pathogen may not have the same dramatic impact on humans as it does on chimpanzees.

Thanks for your reading! Feel free to comment below your thoughts about this topic!