Once a Toxoplasma Parasite Infects Mice, They Never Fear Cats Again
by Rachel Nuwer / September 19, 2013
“Toxoplasma gondii, a protozoan parasite that can only sexually reproduce within cat guts, regularly infects warm-blooded mammals. In healthy humans, it usually does not cause adverse affects, though it can seriously tamper with other species’ behaviors. Infected mice, for example, are known to approach their arch-enemy, the cat, without a shred of fear. Toxoplasma changes the mice’s innate, natural fear of cats, though researchers don’t really understand how the parasite pulls this off. Some speculated that inflammation or parasite eggs in the brain might account for the mice’s inexplicable feline love.
Now, it seems, that is not the case. According to new research, that rewiring persists even after the mice have been purged of their parasite load. Scientists placed ten previously infected and ten never infected mice into enclosures containing traces of either rabbit or bobcat urine. They monitored the mice’s movements and repeated the experiment two weeks, two months and four months after the infected group had first been cured. While the never infected group cowered and avoided the bobcat urine as mice are expected to do, the previously infected rodents were unfazed by the bobcat’s traces.
“Virtually any warm-blooded vertebrate may serve as intermediate hosts“
”It is remarkable that even after the infection has been largely or completely cleared, a profound behavioral change persists,” the authors said in a statement. “Simply having a transient infection resulting in what is potentially a permanent change in host biology may have huge implications for infectious disease medicine.” Toxoplasma is estimated to infect nearly one-third of humans worldwide, but what, if anything, these results mean for humans remains to be seen. At the very least, we can speculate that even if infected people were to rid themselves of their benign, cat-derived parasites, they’d probably still love their kitty just as intensely.”
“…In conclusion, T. gondii infection is fairly common in Asian elephants in Thailand. The prevalence of the infection found in wild animals in Thailand could be of public health and conservation concern. Furthermore, the Asian elephants can be used as sentinels to monitor the potential contamination in the environment with T. gondii. However, updated information on the seroprevalence of this infection in elephants and a risk factor analysis should be performed to determine the actual situation and to identify the infection source and possible transmission routes.”
How ancient horse-dung bacteria is helping locate where Hannibal crossed the Alps
by Chris Allen / April 3, 2016
“Despite thousands of years of hard work by brilliant scholars, the great enigma of where Hannibal crossed the Alps to invade Italy remained unsolved. But now it looks like we may just have cracked it – all thanks to modern science and a bit of ancient horse poo. As a microbiologist, I was part of the team that carried out the research. Hannibal was the leader of the Carthaginian army during the Second Punic War with Rome (218-201BC). He famously led his 30,000 assorted troops (including 37 elephants and over 15,000 horses) across the Alps to invade Italy – bringing the Roman war machine to its knees. While the great general was ultimately defeated after 16 years of bloody conflict, this campaign is now regarded as one of the finest military endeavours of antiquity.
We can say, in retrospect, that these events ultimately shaped the later Roman Empire and therefore the European civilisation as we know it. For more than 2,000 years historians, statesmen and academics have argued about the route he took. Even Napoleon is known to have shown an interest. But until now, there’s not been any solid archaeological evidence. Our international team, led by Bill Mahaney of York University in Toronto, have finally provided solid evidence for the most likely transit route: a pass called the Col de Traversette. This narrow pass between a row of peaks is located on the border slightly south-east of Grenoble in France and south-west of Turin in Italy. Our findings are published in Archaeometry.
The Traversette – found at about 3000m above sea level – is a torturous path even today. The route was first proposed over a century ago by the biologist and polymath Sir Gavin de Beer, but was not previously widely accepted by the academic community. Up to this point, many scholars have instead favoured other routes across such as the Col du Clapier, about 2400m high and further north, which is certainly less treacherous today. This popular choice was largely down to the writings of both modern and ancient historians such as Livy, who lived in Padua around 200 years after the historical event but never actually visited the site of the crossing in his lifetime. So it may be that many of Livy’s accounts are more fictional than factual.
Using a combination of microbial genetic analysis, environmental chemistry, pollen analysis and various geophysical techniques, we unveiled a mass animal deposition of faecal materials – probably from horses – at a site near the Col de Traversette. The dung, which can be directly dated to around 200BC through carbon isotope analysis (very close to the date on historical records – 218BC), was found at a mire or pond. This is one of the few in the area that could have been used for watering large numbers of animals.
The site was originally discovered during geological expeditions to the area, and already fitted descriptions of the terrain – including rockfalls – that Hannibal had to work his way through. Over 70% of the microbes in horse dung are from a group known as Clostridia and we found these microbes in very high numbers in the bed of excrement. Much lower levels of Clostridia genes were found elsewhere at the site. We knew it was these bugs because we were able to partially sequence genes specific to these organisms. The bacteria are very stable in soil, surviving for thousands of years.
So why did Hannibal choose the more difficult Traversette crossing? At this point we can only speculate, but he may not have had a choice at all. Hannibal wasn’t just worried about the actions of the Roman army at this time. In these relatively ancient days there were Gaulish tribes in the region, a major military force, and Hannibal may have been forced to take this more difficult and unexpected route to avoid a devastating ambush.
The finding is exciting, however we cannot yet be absolutely certain that these bacteria do actually come from horses or humans. The gene analysis needs to be expanded with more genetic sequencing of other genes, if this conclusion is to be certain. I am currently leading an extensive microbiology programme to try and assemble either complete or partial Clostridia genomes from the samples taken at the Traversette mire. We may also be able to find parasite eggs – associated with gut tapeworms – still preserved in the site like tiny genetic time capsules.
With this information, we hope to to shed considerable light on the presence of horses, men – and even Hannibal’s famous elephants – at the Traversette mire over 2,000 years ago. This is because with more genetic information we can be more precise about the source and perhaps even the geographical origin of some of these ancient beasts by comparison with other microbiology research studies.”
Hannibal’s Superweapon: The War Elephant
by Elizabeth Lundin / December 21, 2021
“The very idea of the war elephant is almost synonymous with the great Carthaginian general: Hannibal. He was able to win battles with them on their sheer terror factor alone. Imagine, for a moment, that you’re a soldier in a Roman army. You’ve never seen an elephant before. Imagine facing a line of Carthaginian soldiers, and on the horizon looms this armored creature, up to eleven feet tall, maybe six thousand pounds of armored fury, and that creature comes charging at you. It was enough to scatter any army! Hannibal’s armored war elephants are, perhaps, one of the coolest bits of ancient war history. They’ve inspired the imaginations of storytellers for centuries, including the famous J.R.R Tolkien, who re-purposed the idea of Hannibal’s war elephant for his Mûmakil. They were the general’s favorite superweapon. Unfortunately for Hannibal, though, they were also his biggest weakness.
First, a little background on Hannibal Barca, and why exactly he wanted to use something like war elephants to destroy Rome. Hannibal lived during a period of enormous tension in the Mediterranean. He’s often regarded as one of the greatest military strategists to have ever lived, and is, unquestionably, one of the greatest generals of the ancient world. Hannibal was a child during the First Punic War– a war between the Roman Empire, and Carthage, surrounding a power struggle between the two empires. When Hannibal’s father and older brother died, Hannibal took over the Carthaginian army and led it against Rome in the Second Punic War in 218 BC.
He literally wanted to destroy Rome, like, burn it to the ground, because he so believed in the supremacy of Carthage and the superiority of his own people over the Romans. He almost succeeded, almost. Unfortunately, Hannibal’s assault on Rome meant that he had bitten off slightly more than he could chew, and his war elephants didn’t help that fact. Managing them was a logistical nightmare for his army, and it could be said that his love of war elephants was partially responsible for Hannibal’s downfall and his failure to capture Rome.
Nobody can quite agree on where Hannibal got his elephants from. During Hannibal’s time (247 to 183 BC), there were only two varieties of elephant in existence: Asian, and African. Carthage wasn’t exactly very near either of these areas by the ancient world’s standards, and it would’ve been quite an ordeal to obtain the animals. It isn’t clear to historians whether Hannibal used Asian elephants, African elephants, or a combination of both in his army. But, it’s most likely that he used mostly Asian elephants. African elephants run larger than their Asian cousins, and are harder to control.
An army like Hannibal’s would need elephants that could be well-trained and manageable, so Asian elephants seem the most likely choice. The story goes that, in a battle, Hannibal would armor up his elephants, give alcohol with them to get them drunk, and then antagonize them by poking their ankles with spears. Animal cruelty aside, it was an excellent strategy. The elephants, completely drunk and worked up into a fury were easy to work with at that point.
All Hannibal had to do was set them loose on the opposing army, and they’d go crashing through the enemy lines, wreaking havoc. It was the easiest way to force an enemy to break their lines and retreat known to mankind. The trouble with elephants, of course, is that they’re big. They eat a lot of fodder in a day, and Hannibal had sixty in his army that he had to take care of. He did fine, for a while, when the Romans were actually meeting him on the field of battle. He could use the elephants to force the Roman army into retreat, up the body count, and utterly massacre them on the battlefield.
The trouble started when the Romans started to realize that the only way to defeat Hannibal was by a strategy called attrition – basically, they hid in holes, practiced guerilla war tactics, and slowly let Hannibal’s army waste away. Hannibal had no way to fight an army that simply wasn’t there, especially with elephants. Eventually, all his elephants were doing was eating food and forcing him to carry extra stuff around with him to feed them. By the time Hannibal was actually on his way to Rome, many of his own officers advised him to leave the elephants behind. They were only a hindrance, they said. But Hannibal loved his superweapon too much, and his vision of crushing Rome was too important to him, and he needed those elephants to break Rome for good.
Crossing the Alps should have taken Hannibal one week. With his elephants, it took him two. In that time, he lost over half his army, and all but one of his elephants. The animals simply couldn’t withstand the harsh terrain, and his army simply couldn’t sustain their huge appetites and control them properly. By the time Hannibal came out on the other side of the alps, his army was far too weak to be able to sustain a march on Rome itself. Many historians argue that if Hannibal had listened to his officers and left his elephants behind, he would have been able to take the city of Rome and fulfill his vision of destroying the greatest empire the western world has ever known.”