THE Covid-19 pandemic has focused the world’s attention on the potential dangers of human-animal interactions at traditional wet animal markets.
Wild animals are reservoirs for many potential pathogens that, if transmitted to humans, can lead to the emergence of new infectious diseases like Covid-19.
Covid-19 is caused by the virus SARS-CoV-2, which is closely related to bat coronaviruses, and was likely transmitted to humans via another mammal such as a pangolin. Any cultural practices that bring humans and wild animals into close contact increase the risk of unleashing new diseases that can ravage immunologically naïve human populations.
Unfortunately, while governments are at least temporarily cracking down on the wildlife trade at wet markets, many other problematic cultural practices have not received the same scrutiny. As professional primatologists from the Malaysian Primatological Society, a professional organisation committed to studying and protecting Malaysian primates, we have dedicated our lives to the conservation of these amazing animals and are writing to express our deep concerns about the implications of one of these practices - the feeding of wild monkeys and apes by animal lovers.
Monkeys and apes are biologically very similar to humans. As a result, zoonosis, or the transmission of diseases between humans and animals, is particularly likely to occur when humans have close contact with non-human primates.
For example, HIV (Human Immunodeficiency Virus), the virus that causes AIDS, evolved from SIV (Simian Immunodeficiency Virus), a common virus among monkeys and apes in Africa.
The viruses that cause Ebola and yellow fever also circulate in wild primates.
Plasmodium knowlesi, a monkey pathogen that is common in South-East Asian macaques, has also been increasingly crossing the species boundary and infecting humans, recently becoming the most common form of malaria diagnosed in human communities in Sabah and Sarawak.
Several other known pathogens, including a herpesvirus (Herpes B) that has killed 21 of the 50 people known to have become infected, are common in Asian macaques.
Feeding macaques and other primates reduces their natural fear of humans and has led to an increasing number of animal attacks, sometimes resulting in severe injuries to their human victims, and dramatically increasing the risk of zoonotic infection. As human and non-human primates have more contact because of both human encroachment into forests and the resulting movement of primates into human-dominated spaces, the danger increases exponentially.
People who feed wild animals are not only placing themselves and their communities at risk of injury or disease, they are also exposing the animals to potentially lethal diseases. Several recent studies show that human pathogens that cause mild or no symptoms in humans can kill wild primates, and disease outbreaks originating from humans have been implicated in several major disease outbreaks affecting wild African and Asian apes.
The IUCN Primate Specialist Group and the IUCN Wildlife Health Specialist group recently released a statement of concern about the potential for Covid-19 to infect great apes, resulting in the closure of several African national parks to visitors to protect vulnerable populations of chimpanzees, bonobos and gorillas.
Recent viral videos from Thailand show large groups of hungry macaques roaming the streets, searching for food after a sharp decline in tourism deprived them of their ordinary diet of human handouts. While most viewers feel compassion for the suffering of these hungry animals, their sheer number illustrates an important and frustrating biological fact; feeding wild animals increases their rates of reproduction, causing population explosions. So, every monkey that we feed creates more mouths to feed, leading to a vicious cycle of dependency on humans.
With the movement control order and park closures, we have a rare opportunity to reset these detrimental relationships and build a healthier and more respectful way of coexisting in the spaces that we share with other primates. The closure of public parks to visitors have dramatically reduced contact between humans and wild primates and disrupted the monkey’s unhealthy dependence on human food.
Wild primates can eat a broad variety of foods and quickly and flexibly respond to changes in food availability. When the sources of an attractive food, such as human food or food garbage, dry up, they change their search pattern and look elsewhere.
In Lumut, Perak, for example, monkeys that routinely beg for food from park visitors have recently been observed foraging for natural food like molluscs, crabs and plants in nearby mangroves. However, continued feeding of these monkeys by well-intentioned community members may disrupt this adaptive response and perpetuate the problem.
Continued feeding of macaques during the MCO period will create further long-term problems, as luring the animals out of the closed park and to the nearby road increases the likelihood of road kills and the risk of animals crossing into the nearby housing area in search of human food.
Accordingly, we encourage community members and park visitors to stop feeding monkeys and encourage tourism and wildlife authorities to increase their efforts to educate the public about the dangers of feeding wild primates. Wild animals should forage for their food, rather than seeking them from humans, for their health and safety and our own.
So if you love them, please leave them alone!
DR SUSAN LAPPAN, DR NADINE RUPPERT, AINI HASANAH and MUHAMMAD ZAKI ZAINOL
Malaysian Primatological Society