Synthetic biology is changing the way the planet works.
One fact about our time is becoming increasingly well-known. No matter how far you travel, no matter in which direction you point, there is nowhere on Earth that remains free from the traces of human activity.
Despite the moniker, bedbugs evolved long before mattresses and even survived the K-T extinction.
- Scientists originally thought bedbugs evolved on bats roughly 50 million years ago.
- New research used DNA to map the bedbug ancestry and found the species evolved as far back as the Cretaceous.
- The researchers hope that understanding how bedbugs evolve will help us curb their ability to spread and transmit diseases to people.
An international team of scientists have been on a quest. They have traveled to Africa, South America, and South East Asia. They have scaled cliff faces, explored shadow-stained caves, bushwhacked through sweltering jungles, and dodged dangerous wildlife. What treasure did they seek: a golden idol, an ancient codex, a city lost to time?
Nope. They endured all this to procure a blood-sucking parasite that most of us can't wait to be rid of: bedbugs. For 15 years, these scientists traveled the world collected specimens of the family Cimicidae. Their goal was to create a molecular phylogeny — essentially a bedbug ancestral tree mapped through DNA analysis.What they found surprised them.
Bedbugs: Our Mesozoic bedfellows
A bedbug ingests its bloody meal on a human host. Though we do all we can to be rid of them, bedbugs survived the extinction event that wiped out the dinosaurs. (Photo: CDC/Wikimedia Commons)
Bedbugs were previously thought to have evolved with bats, their most common, and long-assumed first, hosts. This origin story kick-starts the bedbug lineage roughly 50 million years ago.
To learn more about these infectious pests, researchers began collecting as many bedbug species they could. Natural history museums and colleagues donated some specimens, but others had to be obtained in the field.
Over the course of 15 years, the scientists traveled the world collecting bedbugs from their natural hosts. These travels took them in proximity to dangerous wildlife like buffalo and leopards, not to mention a few wadings through knee-high guano. In the end, they collected 34 Cimicidae species from 62 locations.
After mapping their molecular phylogeny, the team discovered that bedbugs evolved about 115 million years ago. This new lineage predates bats by about 50 million years, stretching back into the Cretaceous period. Bedbugs roamed the earth alongside dinosaurs such as Triceratops, Velociraptor, and Tyrannosaurs rex.
The team published their results in Current Biology earlier this month.
"To think that the pests that live in our beds today evolved more than 100 million years ago and were walking the earth side by side with dinosaurs was a revelation. It shows that the evolutionary history of bedbugs is far more complex than we previously thought," Professor Mike Siva-Jothy, study co-author from the University of Sheffield's Department of Animal and Plant Sciences, said in a release.
This also means that bedbugs survived the K-T extinction event, the cataclysmic end of the Mesozoic era that saw the extinction of approximately 70 percent of all species living at the time, including, of course, dinosaurs. This puts bedbugs in league with nature's other K-T survivors and all-around badasses sharks, crocodiles, cockroaches, and the platypus.
Did bedbugs nosh on T-rex?
Probably not. While bedbugs evolved alongside the king of the thunder lizards, they likely didn't feed on its blood or any other dinosaur species. As the researchers point out, bedbugs and their relatives favor hosts who have "homes": birds with their nests, bats with their roosts, and humans with their beds. Dinosaurs likely employed a drifter lifestyle, and so wouldn't have been a favored host.
But if neither bats nor dinosaurs were the bedbug's original host, who was? We don't know. The species original host remains elusive.
If that answer is unsatisfactory, take heart that avian dinosaurs — or, as they are commonly known, birds — remain a potential candidate.
Others believe bats, or a bat ancestor, are still in the mix. "The fossil record for [both bed bugs and mammals] are patchy…that makes it hard to make definitive statements," Jessica Ware, an entomologist and evolutionary biologist at Rutgers University, told PBS. "It's possible bats are older, and we've just underestimated."
Evolving pest control
The researchers then used their data to explore the frequency at which bedbugs jump from one host to another. Broadly speaking, some bedbugs become specialized to a single host, but others are more generalized and able to jump between hosts.
The bedbugs that pester humans, Cimex lectularius and Cimex hemipterus, are just two of more than 100 Cimicidae species. These human-gorging bedbugs were thought to have diverged around the time our species entered the game of life — as is true of other human parasites such as lice.
However, the data showed that these bedbugs had evolved already, likely on bats. They opportunistically began snacking on slumbering humans when our species began using caves as dwellings. Throughout our shared history, a new bedbug species has jumped to human hosts about every 500,000 years. However, the way humans have reshaped our environments may speed up that pace.
"These species are the ones we can reasonably expect to be the next ones drinking our blood, and it may not even take half a million years, given that many more humans, livestock, and pets that live on earth now provide lots more opportunities," Professor Klaus Reinhardt, study co-led and bedbug researcher at Dresden University, said in the same release.
According to Siva-Jothy, the team hopes their findings will allow us to better understand the history and abilities of these pests. Understanding their evolution may help us control their ability to spread and transmit diseases to humans.
Over two billion people regularly eat insects. Why are Americans so squeamish?
- Humans have eaten insects for a long time, yet Westerners rarely put them on their plate.
- Insects are a sustainable and nutritious alternative that can help mitigate the effects of climate change.
- Currently, the edible insects market is $55 million and growing.
One of the world's deadliest diseases, malaria takes the life of a child every two minutes.
- Malaria, one of the world's deadliest diseases, kills 435,000 people a year, most of them children in Sub-Saharan Africa.
- Three African countries are set to receive the world's first malaria vaccine this week as part of a WHO pilot program.
- The vaccine has the potential to save the lives of hundreds of thousands of children worldwide.
The 20th century has seen some truly profound advances in human medicine. We now produce clean water and uncontaminated food at unprecedented levels. We've eradicated smallpox and rinderpest — the former having been one of history's deadliest diseases, the latter having caused widespread, depopulating famine — and we're close to eradicating deadly, debilitating diseases such as polio, yaws, and rabies.
But some medical leaps have been more elusive. One of the most devastating has been our inability to find a cure for malaria.
Malaria is among the world's deadliest diseases. It kills 435,000 people worldwide every year, the vast majority in Sub-Saharan Africa. Ninety percent of all malaria-related deaths occur in Africa, and children under the age of five are its most likely victims. In fact, every tenth child death in 2016 was the result of malaria.
But that tragic paradigm may be changing soon. The World Health Organization has launched a pilot program for the world's first malaria vaccine, a change that's been three decades in the making.
Countering the malaria epidemic
Image source: CDC / Wikimedia Commons
The malaria vaccine pilot program will launch in Malawi this week. In 2016, the country suffered 45 malaria-related deaths per 100,000 people. In the coming weeks, Ghana and Kenya will introduce the vaccine as well. In 2016, these countries suffered 69 and 11 deaths per 100,000 respectively.
The vaccine, called RTS,S, will be administered in a regimen of four doses. The first three will be given to children between five and nine months of age. The final dose will be provided around the children's second birthday. The program aims to vaccinate around 360,000 children per year across the three countries. It will focus on areas with moderate-to-high malaria transmission rates in the hopes of maximizing the impact.
"Malaria is a constant threat in the African communities where this vaccine will be given. The poorest children suffer the most and are at highest risk of death," Dr Matshidiso Moeti, WHO Regional Director for Africa, said in a statement. "We know the power of vaccines to prevent killer diseases and reach children, including those who may not have immediate access to the doctors, nurses and health facilities they need to save them when severe illness comes."
WHO's press statement notes that the pilot program is a global partnership. It has brought together a range of in-country and international partners to coordinate with the ministries of health in the three pilot countries. GSK, the vaccine's developer and manufacturer, will donate 10 million doses.
"This is a day to celebrate as we begin to learn more about what this tool can do to change the trajectory of malaria through childhood vaccination," Moeti added.
Difficulties in eradicating malaria
However, the vaccine is not a silver bullet aimed at ending the malaria epidemic. RTS,S does not have a 100 percent success rate, offering only partial protection. In clinical trials, it prevented approximately 4 in 10 malaria cases (3 in 10 for life-threatening malaria).
As such, WHO is presenting the vaccine as a "complementary malaria control tool." The vaccine paired and supported by other preventative measures, including bed nets, indoor insecticides, and antimalarial treatments.
"It's a difficult disease to deal with. The tools we have are modestly effective but drugs and insecticides wear out — after 10, 20 years mosquitoes become resistant. There's a real concern that in 2020s, [cases] are going to jump back up again," said Adrian Hill, a professor of human genetics and director of the Jenner Institute at the University of Oxford, told CNN.
Malaria has proven difficult to eradicate because of its nature. The disease is caused by a parasite of the genus Plasmodium. Its life cycle is split between a sexual stage in its mosquito hosts and an asexual stage in human hosts. When a mosquito bites an infected human, it contracts the disease from that person's red blood cells.
When it bites another person, the mosquito transmits the disease to a new host. The infected patient develops a fever, chills, headaches, and other flu-like symptoms. If untreated, it can develop into severe malaria, where the symptoms can manifest into anemia, organ failure, and neurological abnormalities. Any mosquito that bites this person has the chance to then pass on the disease further.
The difficulty in preventing mosquito bites, the insect's growing resistance to insecticides, and changes the parasite undergoes during its life cycle, all contribute the difficulties on controlling and containing malaria in the world's poorest countries.
Developing sustainable change
Graph showing the percentage of global malaria deaths per world region. Africa accounts for 90 percent of deaths resulting from the disease. (Source: Our World in Data)
WHO's Sustainable Development Goals are 17 directives comprising 169 targets. The ultimate aim is to advance peace and prosperity for all people.
The program's third directive is to ensure health and well-being for all people of all ages. Among its targets are the end of the AIDS, tuberculosis, and malaria epidemics by 2030 and the reduction of mortality for children under 5 to as few as 25 per 1,000 live births worldwide.
Despite the difficulties still ahead, any substantial reduction in malaria deaths is a welcome change and a significant step in achieving this goal.
Thanks to this vaccine, hundreds of thousands of children will likely avoid a crippling, painful death. Communities in some of the world's poorest regions will be given a chance to better stabilize and grow. And the pilot may help scientist develop better strategies for future endeavors.
The vaccine's development came at an auspicious moment, too. Malaria cases began to rise in 2017, after nearly two decades of decline.
"The malaria vaccine is an exciting innovation that complements the global health community's efforts to end the malaria epidemic," Lelio Marmora, executive director of Unitaid, said. "It is also a shining example of the kind of inter-agency coordination that we need. We look forward to learning how the vaccine can be integrated for greatest impact into our work."
Can sensitive coral reefs survive another human generation?
- Coral reefs may not be able to survive another human decade because of the environmental stress we have placed on them, says author David Wallace-Wells. He posits that without meaningful changes to policies, the trend of them dying out, even in light of recent advances, will continue.
- The World Wildlife Fund says that 60 percent of all vertebrate mammals have died since just 1970. On top of this, recent studies suggest that insect populations may have fallen by as much as 75 percent over the last few decades.
- If it were not for our oceans, the planet would probably be already several degrees warmer than it is today due to the emissions we've expelled into the atmosphere.
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