Are the chimpanzees safe from newly discovered pathogens?

-Souradip Mallick, National Institute of Technology, Rourkela

Tacugama in Sierra Leone is the sanctuary for western chimpanzees, a critically endangered subspecies. This sanctuary is the hub of environmental education, ecotourism, and community conservation projects. Ninety-nine chimps permanently reside at Tacugama today. Among them, many of them were rescued as babies from the illegal wildlife trade.

In 2005 many chimps died with epizootic neurologic and gastroenteric syndrome (ENGS). The syndrome varies with some showing neurological signs such as lack of coordination and seizures, and others suffering from gastrointestinal distress—or even both. Even if they recover from ENGS, they only succumb weeks or months, and then died without any warning signs. At that time veterinarians predict some virus attack so they vaccinated every chimp in the sanctuary, treat ill chimps with antibiotics and fluids. But cases kept coming, almost 53 perished between 2005 and 2018.

In 2016 Pan African Sanctuary Alliance, an umbrella organization for the continent’s primate sanctuaries took this matter seriously and discussed this with epidemiologist Tony Goldberg, Owens’ advisor at the University of Wisconsin–Madison. After two and a half years in 2019, the Wisconsin researchers obtained tissue, blood, serum, and fecal samples from 13 chimps that had died of the syndrome and 14 healthy ones. Owens, Goldberg, and their colleagues performed a comprehensive analysis on the samples to characterize all of the viruses, bacteria, and parasites present. Diagnostic sequencing and statistical analyses confirmed that it was the bacterium who is the main causative agent, and this bacterium was not present in any of the healthy chimps, suggesting a link to ENGS.

The causative microbe seemed to be Sarcina ventriculi, which looks like a four-leaf clover and is ubiquitous in water and soil around the world. The species was first discovered in a 19th-century human patient who presented with vomiting, but it then largely disappeared from the scientific literature related to the disease. After genome sequencing, it was revealed that it was unknown Sarcina species, which they named Sarcina troglodytae, and under a microscope, it looks like a cubic structure. It is not clear to them whether it was an emerging new pathogen or Sarcina modified itself, but it is more virulent than Sarcina ventriculi.

Owens and Goldberg hypothesized that there is a diversity of unrecognized Sarcina species, some of which are benign and some of which are opportunistic pathogens. 

The most important question now is how to treat them. Veterinarians are changing their approach to treatment. They give sick chimps antacids, anticonvulsive, antibiotics, probiotics, and a special diet, similar to that of the human. 

Source: Ann Gibbons; “A mysterious disease is killing chimps in West Africa. Scientists may now know the culprit”; Feb. 3, 2021; sciencemag.org;AfricaPlants & Animals; doi:10.1126/science.abg8897

For more articles visit bioXone.in