Exploding population of macaque monkeys and wild pigs poses risk of another global pandemic

Wild pigs and macaque monkeys in Southeast Asia are growing in alarming numbers. This places a dangerous burden on the region’s native forests and poses a risk to human health.

These species are known carriers of diseases that can be transmitted to people. This could potentially lead to outbreaks of diseases among livestock and people, spreading quickly around the world, like COVID-19.

This disturbing news comes from new research by The University of Queensland.

The study was led by Dr. Matthew Luskin from the university’s School of the Environment. He and his team collected and scrutinized data from across Southeast Asia.

Their team was tracking animal populations. The researchers used a network of cameras, set up in various locations, to monitor the species more closely.

“Macaques and wild pigs are taking over Southeast Asia’s disturbed forests,” declared Dr. Luskin.

He blamed human activities for this concerning trend. Our interference with nature, through practices such as logging and establishing palm oil farms, is creating ideal conditions for these animals to thrive.

Wild pig and macaque monkey populations up 400%

The researchers discovered that wild boar and macaque populations were a staggering 400% higher in forests near plantations than in unspoiled environments.

“These animals take full advantage of the farmland, raiding crops and thriving on calorie‐rich foods,” Dr. Luskin said. The cameras set up by Dr. Luskin and his team provided a firsthand view of the skyrocketing animal populations.

He recounted his experience with unnerving troops of macaques in Thailand, Malaysia, and Indonesia. Luskin described how they were everywhere at the forest edges and constantly interfering with their equipment.

Wild pigs and macaque monkeys pose human health risk

The booming populations of wild pigs and macaque monkeys also pose a significant risk to human health. Dr. Luskin referenced the COVID-19 pandemic, which originated from wildlife, as a warning sign of the potential risks.

“Both pigs and macaques are recognized as carriers of diseases that can be transmitted to people and they’re the most common species in a region considered to be the global zoonotic disease hotspot,” he explained.

This sentiment was echoed by Professor Carlos Peres from the University of East Anglia in the UK, who collaborated on the research.

Peres said that abnormally high populations of disease-carrying wildlife species often emerge in human-modified tropical forests. “This study again shows that densely settled rural areas in Southeast Asia may be a source of future human epidemics,” he said.

Impact of wild pigs and macaque monkeys on native plants

Jonathan Moore, a PhD candidate at the University of East Anglia and the Southern University of Science and Technology in China, focused on the immediate effects of these population explosions on the native plants in the affected areas.

Moore observed that pigs and macaques were having a disastrous impact on the local ecosystems. They were destroying seeds and seedlings of native plants.

They were also found to be eating eggs of birds and reptiles. In one striking example, Malaysian pigs alone were found to have reduced rainforest tree regeneration by 62%.

Dr. Luskin argued that swift action was needed to limit the population growth of wild pigs and macaques. Previous efforts to manage the populations have failed due to the animals’ rapid reproductive capacity and public opposition.

“Nobody favors needless killing of wildlife but the negative social and ecological impacts from hyperabundant pest species do demand ethical and urgent management solutions,” Dr. Luskin said, outlining the urgent need for action to curb this ecological crisis.

This research is published in the journal Biological Reviews. It highlights the urgent need for better management of wildlife populations in the wake of human-led changes to their environments.

More about zoonotic diseases

Zoonotic diseases, or zoonoses, are illnesses that animals can transmit to humans. They play a critical role in public health, making up approximately 60% of all infectious diseases in humans.

Notably, some of the most severe disease outbreaks in recent human history, including HIV/AIDS, Ebola, and COVID-19, are zoonotic in origin.

Causes of zoonotic diseases

Bacteria, viruses, parasites, and fungi can all cause zoonotic diseases. The hosts of these pathogens are often vertebrates such as birds, mammals, reptiles, and amphibians.

More specifically, related to this article, wild pigs and macaque monkeys.

People can contract these diseases through several ways. These include direct contact with animals, consuming contaminated food or water, inhaling airborne pathogens, or getting bitten by an infected vector like a tick or a mosquito.

Farmers, veterinarians, and others who work closely with animals are at higher risk of contracting zoonotic diseases. This is due to their regular close contact with animals.

However, anyone can get a zoonotic disease. The impact can range from mild symptoms to severe illness and even death.

Common zoonotic diseases

Some of the best-known zoonotic diseases include Lyme disease, rabies, salmonella, and West Nile virus. Rabies, for instance, spreads to humans through the bite of an infected animal. These are usually wild mammals like a raccoon, bat, skunk, or fox.

Lyme disease, on the other hand, is carried by ticks. These awful pests transmit the bacterium to humans during a bite.

Emerging zoonotic diseases pose a particularly significant threat. These diseases are newly identified or have recently begun to cause problems in certain areas or specific populations.

The most recent and impactful example of an emerging zoonotic disease is COVID-19. It was caused by the SARS-CoV-2 virus, believed to have originated in bats.

Prevention methods

Preventing zoonotic diseases requires a coordinated effort in both human and veterinary medicine. The One Health approach, for example, emphasizes this interdisciplinary collaboration. It recognizes that the health of people, animals, and our environment is deeply interconnected.

For individuals, good hygiene practices can reduce the risk of zoonotic diseases. This includes washing hands after handling animals, cooking meat thoroughly, and avoiding direct contact with wild animals.

Zoonotic diseases represent a significant part of our disease burden. They emerge from our interactions with animals and the environment. We must use a comprehensive approach to manage and prevent them effectively.