Sloths, often perceived as slow-moving and docile creatures, have captivated public interest, leading to questions about their health and potential disease transmission to humans. Understanding their health status helps clarify potential health considerations.
Common Ailments in Sloths
Their fur, which often appears green due to symbiotic algae, also harbors a diverse community of microorganisms and invertebrates. This unique ecosystem can include various parasites, fungi, and bacteria, some of which can impact the sloth’s health.
Internal parasites are common, with captive sloths frequently infected with Coccidia and tapeworms, leading to symptoms like diarrhea and weight loss. Studies on wild sloths reveal a range of gastrointestinal parasites, though two-fingered and three-fingered species in the same areas often host different parasite communities.
External parasites, such as ticks and mites, affect sloths. The “giant sloth tick,” Amblyomma varium, is a host-specific tick, though sloths’ naturally low body temperature makes them less prone to heavy tick infestations than many other mammals.
Fungal infections can occur, and Candida species cause candidiasis in two-toed sloths, particularly when their immune systems are compromised, such as in captive settings. Interestingly, some fungi found in sloth fur have demonstrated bioactivity against parasites, like those causing malaria and Chagas disease, and even against certain cancer cells in laboratory studies. Sloth fur also contains various bacteria, including those that produce antibiotics, which may help regulate pathogenic microbes within their fur ecosystem. Sloths can experience bacterial issues like respiratory diseases caused by agents such as Bordetella bronchiseptica and Escherichia coli, and some may suffer from gastrointestinal upset or diarrhea due to bacterial infections.
Zoonotic Risks and Transmission
While sloths face their own health challenges, some diseases they carry can be transmitted to humans. These zoonotic diseases spread primarily through direct contact, indirect contact with contaminated environments, or vector-borne transmission. Understanding these pathways is important for minimizing risk.
The Oropouche virus, commonly called “sloth fever,” is a zoonotic concern. Sloths are reservoir hosts for this virus, along with birds, primates, and rodents. However, it is not transmitted to humans through direct contact with sloths; instead, it spreads via the bites of infected biting midges and certain mosquitoes. Symptoms in humans include fever, severe headache, muscle aches, and joint pains, with neurological complications occurring in some cases.
Another pathogen associated with sloths is Leishmania, the parasite responsible for leishmaniasis in humans. Sloths can serve as reservoir hosts, harboring the parasite without showing signs of illness. Sandflies, the actual vectors for Leishmania, do not live in sloth fur, and the disease is not transmitted to humans through direct contact or sloth bites. Human infection occurs when a sandfly, after biting an infected animal, then bites a person.
Rabies is a severe viral disease carried by many mammals, including sloths. While sloths can theoretically transmit rabies through a bite, documented cases of rabid sloths or human transmission from sloths are rare. Any animal bite should be medically evaluated, as post-exposure rabies treatment is often recommended if the animal’s rabies status is unknown. Salmonella species have been isolated from sloths, particularly in captive populations. This bacterium, commonly shed in feces, can pose a risk to humans, especially those in close contact with the animals or their environments.
Minimizing Risk During Interactions
Interacting with any wild animal carries risk, and sloths are no exception. Adopting preventative measures protects both human health and the animals’ well-being. Observing sloths from a distance is always the safest approach, whether in their natural habitat or in controlled settings.
Direct physical contact with sloths should be avoided, as this eliminates the risk of bites, scratches, or exposure to pathogens on their fur or skin. Even seemingly minor contact could potentially expose individuals to bacteria or fungi that might be harmful. Avoiding handling wild sloths is particularly important, as it can cause stress to the animals and increase the likelihood of disease transmission.
Practicing good personal hygiene is a simple yet effective preventative measure. Thoroughly washing hands with soap and water after any potential exposure to sloths or their environment significantly reduces the risk of pathogen transmission. For protection against vector-borne diseases like Oropouche virus, which is transmitted by biting insects rather than direct sloth contact, using insect repellent, wearing long-sleeved clothing, and staying in screened areas are recommended, especially when traveling in regions where the virus is prevalent.