🐼🧑‍⚕️2.12 Panda Base VH X SU MedSchool: My Research Findings on Panda Parasites

Late last year, I joined a collaborative program between the Chengdu Research Base of Giant Panda Breeding and Sichuan University on panda microbiome and disease prevention as a researcher. Due to confidentiality agreements, we had to keep our work and findings private until today.

For the past two months, my photo album and WeChat history have been filled with images of parasites. Now, I can finally clear them out. I’m sharing some of our key findings for the past three months: humans and giant pandas face similar challenges with parasites.

Humans and giant pandas share a common "annoyance" that has troubled us since the beginning of time – parasites, those tiny creatures with big consequences.

Warning: The following content contains real images of parasites. Viewer discretion is advised!

The battle between humans and parasites has been ongoing for centuries. In the Sui Dynasty, medical text Zhu Bing Yuan Hou Lun mentioned "nine worms," which refer to ascaris, pinworms, tapeworms, and others. Ascaris is also the most common internal parasite in wild giant pandas. According to scientific research, the infection rate of ascaris in wild giant pandas is 100%, with one rescued panda having been found with as many as 1,605 ascaris worms. In captivity, pandas receive good medical care, so the infection rate and intensity of intestinal parasites are generally lower, rarely posing a serious threat to their lives.

Diagram of the lifecycle of parasites in a giant panda.

Over the centuries, humans have continuously devised ways to combat parasites, but these "highly intelligent" creatures have also evolved. For example, ascaris worms have adapted to the narrow intestinal space by evolving into a thread-like shape. Female ascaris worms can lay up to 200,000 eggs per day. Many other parasitic worms have developed suction cups or hooks to resist the digestive tract's movements.

Common Parasite Diseases in Giant Pandas

Ascariasis: The cause of ascariasis in giant pandas is Baylisascaris schroederi. Wild pandas are most susceptible to ascaris infections from birth until they leave their mother. Most pandas are already infected before they leave their mother’s care. Ascaris can live in the panda's body for 1-2 years, and their fertilized eggs are excreted in the feces. Under the right temperature and humidity, these eggs become infectious in 2-3 weeks and can survive in the environment for months. When pandas ingest these eggs, they hatch in the small intestine, leading to continuous reinfection.

Clinical Symptoms: Baylisascaris typically resides in the small intestine but has also been found in the mouth, larynx, trachea, and stomach of pandas, and can even enter the bile ducts, causing blockages, inflammation, and sometimes death. While cases of death from ascariasis are rare in captive pandas, there have been numerous reports of wild pandas dying from it. Common pathological changes include blockages caused by ascaris in the bile ducts, liver ducts, and pancreatic ducts, as well as hemorrhagic pancreatitis and organ damage.

Prevention and Treatment:

- Regular screening for parasites and deworming.

- Disinfect panda enclosures and equipment regularly to maintain cleanliness.

-New pandas should be quarantined, disinfected, and dewormed preventatively.

Now that we've covered internal parasites, let's look at the external ones – the "invisible assassins" known as ticks!

Tick-borne Disease: Ticks, also known as mites, vary in size from sesame seeds to grains of rice. They commonly attach to the skin in areas where it’s hard to scratch. While over 900 species of ticks are known globally, only some cause disease in humans. In China, there are over 100 species of ticks, 12 of which can infect giant pandas. Ticks are more common in wild pandas but can also affect captive ones. Ticks can mix in varying degrees on the same panda, with some species being more harmful than others, such as Haemaphysalis flava and Ixodes acutitarsus.

Symptoms and Effects: Ticks can transmit viruses, bacteria, and parasites that seriously threaten panda health. They mainly attach to areas with thin fur, like the abdomen, limbs, neck, and eyes. A few ticks might cause little harm, but in large numbers, they can cause severe anemia, and some ticks even secrete toxins leading to paralysis or coma. Ticks like Haemaphysalis flava are especially dangerous due to their population size and blood-sucking ability.

Prevention and Treatment:

- Diagnosing tick infections by detecting them on the skin.

-Treat according to weight, with a second treatment after 4-5 days for better results.

-Severely infected pandas should receive fluid therapy and antibiotics to control secondary infections.

-It’s important to also eliminate ticks in the environment and prevent secondary infections from internal parasites.

-Proper care and feeding should be maintained to promote recovery from anemia caused by ticks.