Parasites - their role and value

Mind-bending, body-snatching, blood-sucking: parasites are bizarre yet vital for life on Earth

ijimino, Shutterstock

Euan Ritchie, Deakin University

Parasite, zombie, leech – these words are often used to describe people in unkind ways. Many of us recoil when ticks, tapeworms, fleas, head lice or bed bugs are even mentioned. Coming across such unwelcome guests – in our hair, on our skin or in our beds – can be a real nightmare.

Some parasites cause horrific deformities and diseases, maiming and killing millions of people and wildlife. Others may help boost immunity or provide the basis of food chains.

Parasites are often demonised and misunderstood. But the more we study these oddities and wonders of evolution, the more we appreciate their vital roles in ecosystems and our complex relationships with them. They’re essential to life on Earth.

As an ecologist with a focus on wildlife and conservation, I wrote this article to share some of my fascination for parasites and the importance of their extraordinary lives.

Cuckoos are known as brood parasites, tricking other birds into raising their own young.

What is a parasite?

Parasites rely on living organisms for food, to grow and to reproduce.

They can either live on the outside (ectoparasites) or inside (endoparasites) of their hosts. Far from being invited dinner guests, parasites typically turn up of their own accord and feed at the host’s expense, consuming part or all of them.

Parasites can live within their host (or hosts) for short or extended periods – in some cases many years – going largely unnoticed. For instance, one man lived with a tapeworm in his brain for more than four years until the headaches and strange smells become too much to bear. In other cases, parasites can kill their host.

Perhaps the most gruesome type of parasite, parasitoids, kill their hosts in order to reproduce. The disturbing chest-bursting scene from the 1979 movie Alien is a truly visceral sci-fi example of a parasitoid.

In real life, examples include spider wasps that first immobilise their spider prey, lay an egg on them, and bury them. Then when the egg hatches, the wasp larvae devour the incapacitated spider. That is, of course, if another animal such as a “bin chicken (Sacred Ibis)” or insect doesn’t intervene.

Parasites are widespread and profoundly affect our world.

Parasites are typically much smaller than their hosts. Many are furnished with equipment for latching on and remaining attached, including hooks, suckers and “teeth”.

Endoparasites such as tapeworms are often flat, allowing them to live within the tight spaces inside other organisms. The flatworm Diplozoon paradoxum that lives in gills of some fish must conjoin with another to reach adulthood and reproduce. Once fused, they form a permanent, lifelong bond and mate with each other over many years.

As much as 40% of all animal species may be parasites, and this mode of life might have evolved more than 200 times in the animal kingdom. But parasitism is not solely confined to animals. Many plants, fungi, protists, bacteria and viruses are parasites too.

Parasite powers

The leech scene in the iconic 1986 movie Stand By Me comes back to me every time I walk through a damp forest. The idea of providing a blood meal for another species sparks fear in many people. But leeches may also come to our aid, either by helping to reduce pooling of blood or reestablishing blood flow to areas post-surgery. Their anaesthetic saliva also has anti-inflammatory and anticoagulant properties, which are advantageous for medical procedures.

As the blood of leeches contains DNA from their past meals, conservation scientists can use them to search for rare and cryptic wildlife.

Leeches are aiding wildlife conservation.

One of the world’s most widespread parasites is Toxoplasma gondii. Some estimates suggest as many as one in three people are affected. This parasite’s main host is cats, large and small species. House cats are frequently infected, spreading this parasite through their faeces.

While many infected people appear to have no symptoms, serious effects can include organ damage, complications with pregnancy or abortion, erratic risk-taking behaviour, mental conditions, and more traffic accidents than unaffected people.

There are potential “benefits” too. Research suggests Toxoplasma infection, which can increase confidence and risk-taking, may even be linked with increased entrepreneurial and business-related activities. Indeed, this same study found that nations with higher rates of toxoplasmosis had a lower proportion of individuals concerned about failure related to new business ventures.

Toxoplasmosis is associated with a vast array of symptoms and medical conditions.

Toxoplasma gondii manipulates its host to increase transmission and continue its life cycle. Infected rodents may become unwitting participants in a game of cat-and-mouse-and-parasite in which they lose their fear of cats and instead become attracted to them.

Rather than manipulating host behaviour, as in the case of fungi that turn ants into zombies, some parasites cause body malformations. This makes hosts more likely to become prey for subsequent hosts and hence to continue the parasite’s life cycle. One of the most striking examples is a trematode (flatworms often known as flukes) that causes missing legs, extra legs or deformed legs in frogs and other amphibians. Extra legs, in some cases several, serve no function and simply impede movement, making it harder to escape predators.

Sometimes extra legs are a hindrance not helpful. Brett Goodman and Pieter Johnson

Parasites are fundamental to ecosystems and require conservation

Parasites are a big part of life on Earth. A study on the Californian coast found the sheer mass of parasites exceeded that of top predators. In particular, the biomass of trematodes was greater than that of birds, fish, burrowing shrimps and polychaetes (marine worms).

Evidence suggests ecosystems rich in parasites are healthier than those with fewer parasites. But there is increasing concern for the survival of these species amid a growing extinction crisis. So a global plan for parasite conservation was proposed in 2020, with priorities including increased data collection and genetic analysis, making conservation assessments, and raising public awareness.

Sadly, parasites can inflict great pain, meat allergies, suffering, and a heavy death toll. Malaria, schistosomiasis (sometimes referred to as snail fever, bilharzia, and Katayama fever), and sleeping sickness are just a few examples.

But they also shape our world in profound ways, have crucial ecological roles, and paradoxically, may in some cases help keep us healthier. Though it may be confronting to admit, we need parasites as much as they need us.

The presence of parasites (Gyrodactylus turnbulli) can affect how colourful male guppies are, influencing their ability to attract mates. Wikimedia commons, CC BY

Euan Ritchie, Professor in Wildlife Ecology and Conservation, School of Life & Environmental Sciences, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Artificial Intelligence: it's all in the coding or is it ?

Sample 1 - AI created avatar - female

Sample 2 -AI created avatar - male

 

Considerable public debate has ensued on the positives and negatives (aka benefits versus risks) of Artificial Intelligence [AI]. The capability of the new systems cannot be fully quantified at this time however there are simple tests to demonstrate how such systems can interpret commands provided to them by users. On even a very simple, superficial level, AI can produce dramatically different results for the same question or request by a user.

The test above is one such example. A well known AI programme was tasked by a user to create an avatar image to assist the user to interact with the AI programme. The request was very basic without any significant details as to what image should be developed other than one should be female and one should be male with a positive expression. The AI program produced sample 1 for the female image and sample 2 for the male image. Is there an bias inherent within the AI programme ? That is hard to prove however the two images created could not be more different. Sample 1 is a very humanistic female image with a pleasant interactive professional expression. Sample 2 is an abstract almost idiotic impression of a non gender entity yet the instructions for each sample, female and male were identical and made at the same time. 

New Year 2025 - change and uncertainty remain the themes

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As the calendar year of 2024 draws to a close, the time for rest, recreation and reflection on the past year and consideration of the year ahead is a time-honoured pastime. 2024 was a difficult year and does provide a partial events map of what may eventuate in 2025. A few critical influences to consider are listed below -

International relations: the Russian (Putin-initiated) unilateral war on Ukraine continues into another year with the exacting and tragic toll of civilian life unabated. The outcome is unknown as there are, like most major military conflicts, many variables whether political, technological (military)or social that will impact the course of the conflict. The war is one which does draw in multiple parties and cannot be defined only as regional conflict. The election of Donald J Trump as US President may affect the continuation of the war or it may not. 

The Middle East remains a hotbed of turmoil with the ongoing Israel-Palestinian (Hamas) conflict together with the action taken by Israel against Hezbollah in Lebanon being central. The wildcard change has been the fall of the Assad regime in Syria that has been replaced by a collection of groups that formed the opposition to his dictatorship. Syria at present is geographically divided into different zones under various groups. Whether a cohesive multi-religious state can emerge from this situation is pure guesswork but the odds are not in favour of this outcome. Yemen and the Houthi insurgency continues to add a smaller yet measurable level of Middle Eastern instability.

Politics: the returning US President, Donald J Trump takes office in January 2025. Given the experience of Trump politics in the first Trump presidency,  a fairly chaotic four years is the likely result. In the UK, the election of a Labour Government in July 2024 under Sir Keir Starmer has surprisingly led to a series of scandals in the first few months thus removing any sense of even a honeymoon period for the new leadership. In Europe, the Right of the political spectrum have gained much stronger positions in Holland, Italy, France, Austria and Germany reflecting considerable dissatisfaction with centrist or moderate left wing governments. There is no sign of this trend reversing in the next 12 months. Elsewhere totalitarian regimes continue in Russia, China and North Korea.

Economies: Economic instability and volatility will continue in 2025 with even more fluctuations as the Trump US Presidency gets underway and continuing conflicts in Eastern Europe and the Middle East . The real risk of either increased inflationary pressures or conversely stagflation cannot be underestimated. The slow-down in China exacerbated by the real estate/property development bubble then decline has proven to be difficult to counter and China's government has chosen the less effective policies to deal with it. 

Environment and Climate Change: irrespective of what government is in power or what conflicts are occuring, the climate will change due to the increase in termperature with carbon emissions continuing at a high level and the risk of the release of higher methane emissions in the Northern Hemisphere ever more likely. Ice sheets and glaciers continue to melt at a higher than projected rate and sea level rises are correspondingly continuing. The reality that the agreed limitation of temperature increase to 1.5C cannot be met has yet to be formally acknowledged although many climate scientists have published that conclusion. Any reduction in the efforts to reduce carbon emissions and/or not move to sustainable renewable energy generation would lead to a dismal outcome for the planet and the human race. Each and every year counts at this point in time.

2025 at this stage promises more of the same from this perspective. At a more positive level there are many more ongoing discoveries in science and health and hope for the future is not to be discounted.

Wherever you are living in the world, may 2025 be a healthy, happy and peaceful year.  

Astronomy - Dark Comets

What is a dark comet? A quick guide to the ‘new’ kids in the Solar System

Artist’s impression of ‘Oumuamua. ESA/Hubble, NASA, ESO, M. Kornmesser

Rebecca Allen, Swinburne University of Technology; Kirsten Banks, Swinburne University of Technology, and Sara Webb, Swinburne University of Technology

In 2017, NASA discovered and later confirmed the first interstellar object to enter our Solar System.

It wasn’t aliens. But artist impressions of the object (called ‘Oumuamua, the Hawaiian word for “scout”) do resemble an alien spaceship out of a sci-fi novel. This strange depiction is because astronomers don’t quite know how to classify the interstellar visitor.

Its speed and path around the Sun don’t match a typical asteroid, but it also has no bright tail or nucleus (icy core) we normally associate with comets. However, 'Oumuamua has erratic motions that are consistent with gas escaping from its surface. This “dark comet” has had astronomers scratching their heads ever since.

An artist’s impression of the dark comet ‘Oumuamua. European Southern Observatory / M. Kornmesser

Flash forward to today, and more of these mysterious objects have been discovered, with another ten announced just last week. While their nature and origins remain elusive, astronomers recently confirmed dark comets fall into two main categories: smaller objects that reside in our inner Solar System, and larger objects (100 metres or more) that remain beyond the orbit of Jupiter.

In fact, 3200 Phaethon – the parent body of the famous Geminid meteor shower – may be one of these objects.

How do dark comets differ from normal comets?

Comets, often described as the Solar System’s “dirty snowballs”, are icy bodies made of rock, dust and ices. These relics of the early Solar System are critical to unlocking key mysteries around our planet’s formation, the origins of Earth’s water, and even the ingredients for life.

Astronomers are able to study comets as they make their close approach to our Sun. Their brilliant tails form as sunlight vaporises their icy surfaces. But not all comets put on such a dazzling display.

The newly discovered dark comets challenge our typical understanding of these celestial wanderers.

Image of comet C/2023 A3 Tsuchinshan-ATLAS taken by astronauts aboard the International Space Station. NASA

Dark comets are more elusive than their bright siblings. They lack the glowing tails and instead resemble asteroids, appearing as a faint point of light against the vast darkness of space.

However, their orbits set them apart. Like bright comets, dark comets follow elongated, elliptical paths that bring them close to the Sun before sweeping back out to the farthest reaches of the Solar System.

They go beyond Pluto, some even making it out to the Oort Cloud, a vast bubble of tiny objects at the fringe of our Solar System. Their speed and paths are what allow astronomers to determine their origins.

A comparison of dark comets and bright comets set against the Milky Way. On the left, a small, rocky, dark comet represents their typical size of one metre to a few hundred metres wide. On the right is a larger, icy, bright comet with a glowing tail, whose size ranges from 750 metres to 20 kilometres wide. The stark difference in size explains why dark comets lack the bright, visible tails of their larger, more iconic counterparts. Composition: Dr Kirsten Banks; Background image: R. Wesson/ESO; Dark comet: Nicole Smith/University of Michigan, made with Midjourney; Bright comet: Linda Davison

But what makes these comets so dark? There are three main reasons: size, spin and composition or age.

Dark comets are often small, just a few metres to a few hundred metres wide. This leaves less surface area for material to escape and form into the beautiful tails we see on typical comets. They often spin quite rapidly and disperse escaping gas and dust in all directions, making them less visible.

Lastly, their composition and age may result in weaker or no gas loss, as the materials that go into the tails of bright comets are depleted over time.

These hidden travellers may be just as important for astronomical studies, and they may even be related to their bright counterparts. Now, the challenge is to find more dark comets.

How can we find dark comets?

How do we even find these mysterious dark comets in the first place? As they get closer to the Sun, we don’t see spectacular tails of debris.

Instead, we rely on the light they reflect from our Sun.

Several astronomical images are combined to capture the faint, fast moving object ‘Oumuamua in the centre. The white streaks are stars. ESO/K. Meech et al.

These little guys might be stealthy for our eyes, but they are often no match for our large telescopes around the world. The discovery of ten new dark comets revealed last week was all thanks to one amazing instrument, the Dark Energy Camera (DECam) on a large telescope in Chile.

This camera can’t “see” dark energy directly, but it was designed to take massive photos of our universe – for us to see distant stars, galaxies and even hidden Solar System objects.

In their recent study, astronomers pieced together that some of these nightly images contained likely dark comets.

A) The Dark Energy Camera (DECam), mounted on the Victor M. Blanco four-metre telescope at the Cerro Tololo Inter-American Observatory in the Chilean Andes (Credit: Dark Energy Survey). B) Two examples of newly discovered dark comets within the DECam data, from Seligman et al. (2024).

The good news is, we are starting to focus more attention on these objects and on how to find them.

In even better news, in 2025, we’ll have a brand new mega camera in Chile ready to find them. This will be the Vera C. Rubin Observatory, with the largest digital camera ever built.

It will allow us to take more images of our night sky more quickly, and see objects that are even fainter. It’s likely that in the next ten years we could double or even triple the amount of known dark comets, and start to understand their interesting origin stories.

There could be more 'Oumuamua-like objects out there, just waiting for us to find them.

Rebecca Allen, Co-Director Space Technology and Industry Institute, Swinburne University of Technology; Kirsten Banks, Lecturer, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, and Sara Webb, Lecturer, Centre for Astrophysics and Supercomputing, Swinburne University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Christmas 2024

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Christmas each year is a time of celebration, mixing with family and friends, observing religious rituals notably prayer / carol singing and exchanging gifts. Usually there is a message of sharing goodwill and generosity to those around us. Often it is also a time of considerable stress and isolation for others where families are in difficult domestic circumstances or there is separation by time and distance between family members. For the very old, whom may have outlived their peers and partners it can be especially difficult.

The origins of the Christmas celebration are considerably more humble than the current focus of materialistic consumerism. Until the 20th Century it was a more modest time with the emphasis on the spiritual experience.

The modern Christmas tree with decorations originates from Central Europe, predominantly Germany and the countries now known as Latvia and Estonia with records suggesting it became a common practice in the 16th Century. The Renaissance period in Europe is the most likely point in time when it commenced and gained wider use within the Lutheran Church and the Holy Roman Empire. The tree was decorated with representations of roses made from coloured paper, apples, wafers and sweet meats with a later addition being some candles. In its current form, the Christmas tree with electrification is effectively an extravagent light show in contrast. 

With the earlier version of simplicity in mind, wherever you may be, Merry Christmas.

World Economic Forum - January 2025

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The next meeting of the World Economic Forum (WEF) will be held as usual in the Swiss ski resort town of Basel from 20 January to 24 January 2025.

What is the World Economic Forum ? 

The WEF is headquartered in Geneva, Switzerland, and is an international not-for-profit organization focused on promoting cooperation between the public and private sectors. It was founded in 1971 by German economist Klaus Schwab, and the forum seeks to "foster a spirit of collaborative entrepreneurship to address global issues and shape governmental, industry, and social agendas".

Who attends the WEF  ? 

Some 2,500 delegates and hundreds of other participants, observers and groups gather in Davos during this period and consequently the WEF claims "..it is possibly the largest assembly of global decision makers each year". The WEF describes its attendees as a "highly curated group of delegates from global business, government, civil society, media and academia who converge on Davos to address the most pressing issues of the day and ultimately develop solutions". "Curated" is itself a very unusual term to describe an an ïnvitation-only" event.  

What is the agenda for the January 2025 WEF ?

The WEF has published the theme for Davos as being “Collaboration for the Intelligent Age” with the program to be oriented around five interconnected priorities:

• Reimagining growth. Given today’s geopolitical and economic realities, policy makers will need to look toward new sources of growth for the future. The digital economy already accounts for nearly 16 percent of global GDP and could form the basis for up to 70 percent of all new value created in the global economy over the next decade.

• Industries in the intelligent age. Technology is now the primary driver of change and disruption across business sectors. To take full advantage of the plethora of opportunities, leaders will need a new tool kit to help themselves, and their organizations, adapt.

• Investing in people. Technological advancements have created the need to reskill and upskill people to meet the demands of tomorrow’s economy.

• Safeguarding the planet. Partnerships and dialogues that enable investment and deployment of new climate technologies are critical to making progress on global climate and nature-related goals. A scaling up of ambition, governance, partnerships, and capital will be necessary to achieve net zero.

• Rebuilding trust. As the pace of change accelerates, societal divides have deepened as people around the world seek to reaffirm their identities. To move forward, stakeholders will need to find new ways to collaborate—both internationally and within their own societies.

The WEF is essentially a meeting of key economic leaders, organisations and ''drivers'' of economic and social activity.  It could be best described as a private sector/non government version of formal government forums such as the G7 or G20 or a form of capitalist mega think tank. The Davos WEF however cannot negotiate or manage global wide treaties, agreements or trade relationships as it does not have that role nor power. It has often been seen as quite exclusive and elitist despite its stated intention.

Syria and the collapse of the regime

Bashar al-Assad’s regime has fallen in Syria. How will this change the Middle East?

Ali Mamouri, Deakin University

The swift and unexpected fall of the Syrian capital, Damascus, to Sunni opposition forces marks a pivotal moment in the modern history of the Middle East.

Bashar al-Assad’s regime had withstood more than a decade of uprisings, civil war and international sanctions since the onset of widespread protests in 2011. Yet, it collapsed in a remarkably short period of time.

This sudden turn of events, with the opposition advancing without significant battles or resistance, has left regional powers scrambling to assess the fallout and its broader implications.

This dramatic development signals a reshuffling of power dynamics in the region. It also raises questions about Syria’s future and the role of its neighbours and global stakeholders in managing the post-Assad landscape.

What does the future hold for Syria?

With the collapse of the Assad regime, Syria now finds itself fragmented and divided among three dominant factions, each with external backers and distinct goals:

1. Syrian opposition forces, led by Hayat Tahrir al-Sham: These groups, supported by Turkey, now control central Syria, extending from the northern border with Turkey to the southern border with Jordan.

Although they share a common religious identity, the Sunni factions have a history of internal conflicts, which could hinder their ability to form a cohesive government or maintain long-term stability.

The opposition forces range from former jihadists coming from Islamic State and al-Qaeda to secular groups such as the Syrian National Army, which split from Assad’s army after the 2011 uprising.

2. Kurdish forces: The Kurdish groups control territory in northeastern Syria, bordering Turkey in the north and Iraq in the east. They continue to receive support from the United States, which has established military bases in the area. This support risks escalating tensions with Turkey, which views Kurdish empowerment as a threat to its territorial integrity.

3. Alawite forces: Pro-Assad Alawite factions, primarily situated in the coastal regions of western Syria, maintain strong ties with Iran, Iraq and Lebanon’s Hezbollah militant group. These areas could serve as a stronghold for remnants of Assad-aligned groups after the opposition’s takeover, perpetuating sectarian divides.

The stark divisions among these groups, combined with the absence of a mutually acceptable mediator, suggest that Syria may now face prolonged instability and conflict.

How will this impact the region?

The swift fall of the Assad regime has profound implications for the major players in the Middle East.

The Sunni rebel forces, with strong Turkish backing, capitalised on a moment of vulnerability in Syria. The Assad regime’s allies were preoccupied — Russia with its ongoing war in Ukraine, and Iran and its proxies with their ongoing conflict with Israel. This provided a strategic opportunity for the rebels to advance swiftly across Syria to the capital, Damascus.

Turkey already effectively controls a strip of territory in northern Syria, where its military has been fighting Syrian Kurdish forces. Now, with the victory of its Syrian opposition allies, Turkey is expected to expand its political and military influence in Syria, causing more challenges for the Kurdish minority fighting for its autonomy.

Israel is also in a strategically better position. The fall of Assad disrupts the so-called “axis of resistance”, comprised of Iran, Syria and Tehran’s proxy groups like Hezbollah in Lebanon, Hamas in Gaza and the Houthi rebels in Yemen.

Iran’s critical military supply lines to Hezbollah will likely be severed, isolating the militant group and likely weakening it even further.

Additionally, the fragmentation of Syria into ethnic and religious factions could diminish the regional focus on Israel, providing space for it to pursue its broader strategic goals. After Israel agreed to a ceasefire with Hezbollah last month, for example, Israeli Prime Minister Benjamin Netanyahu emphasised a shift in focus to countering the “Iranian threat”.

Iran, meanwhile, has the most to lose. Assad was a crucial ally in Iran’s regional proxy network. And the collapse of his government follows the significant damage that Israel has already inflicted on its other partners, Hamas and Hezbollah. Iran’s regional influence has now been severely diminished, leaving it more vulnerable to direct conflict with Israel.

The fragmentation of Syria also poses significant security risks to its neighbouring countries – Turkey, Iraq, Jordan and Lebanon. Refugee flows, cross-border violence and sectarian tensions are likely to escalate. Turkey is already hosting more than 3 million Syrian refugees – many of whom it hopes will return home now that Assad’s government is gone.

For Iraq and Lebanon, this instability could exacerbate their fragile political and economic situations. The Balkanisation of Syria along ethnic and religious lines could encourage other groups in the region to rebel against governments in the pursuit of their own autonomy. This risks entrenching divisions and prolonging conflict across the region.

While many Syrians have celebrated Assad’s fall, it remains to be seen whether their lives will improve much. With the absence of a unified and internationally recognised government in Syria, sanctions are unlikely to be lifted. This will further strain an already devastated Syrian economy, deepening the humanitarian crisis and potentially fuelling extremism.

Ali Mamouri, Research Fellow, Middle East Studies, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.