Tag Archives: tick

These African ticks survived for 8 years without food. Females laid eggs years after the last male had died

Argas brumpti. Credit: Jonathan Cohen.

The toughest animals on Earth are often not what you expect. A prime example is the eight-legged tardigrades capable of surviving extreme heat, cold, and even the vacuum of space. But there’s another tough guy you should know about, especially since they often like to take on humans. Meet the East African tick, a blood-sucking arachnid that can go without food for at least 8 years, and with a lifespan of over 27 years. What’s more, females have been able to lay eggs even 4 years after the last male in their group had died.

The remarkable longevity and resilience of the East African (Argas brumpti) tick were just recently revealed by a rare study almost 60 years in the making, which could be a separate story in itself, illustrating the virtues of patience in science.

It all started in 1976, when Julian Shepherd, an associate professor of biological sciences at Binghamton University in New York, was given six adult females, four adult males, and three nymphs of A. brumpti collected from caves near Nairobi, Kenya. He decided to monitor them in his lab in a habitat with stable conditions, where they were fed periodically on mice, rabbits, or drawn rat blood.

For years, the captive ticks enjoyed their regular feast until one day Shepard simply stopped giving them blood when his lab ran out of rabbits and mice to feed on. Little did the biologist realize at the time that, even starving, his original group of ticks would survive until the next century.

East African ticks have soft and leathery skins, unlike the hard shell sported by the common types of ticks that you’ll find in the parks and countryside. And unlike your run-of-the-mill tick, Argas brumpti is not reported to carry any diseases, although its bites can cause substantial, painful lesions with aftereffects sometimes persisting for many months and even years, something that Shepard knows from first-hand experience.

In their natural habitat, the ticks reside in shallow caves, rocky areas, or dust-bath areas used by their favorite prey, such as small to large mammals and lizards, notably in the dust around termite mounds that large mammals rub against. This perennially dry environment with few opportunities to encounter hosts may explain A. brumpti‘s extreme longevity, even within a taxon renowned for sustained survival even without food or water.

“I am always enthralled by the adaptations of organisms to their environment—in this case, a dry environment with virtually no access to water for long periods of time and a lifestyle that must wait for very long intervals of no food between encounters with host animals,” Shepherd said in a statement.

Adaptations to its environment may explain another incredible feat. Four years after the last original tick died, the females continue to live for another four years. These hungry females were eventually fed, and much to Shepherd’s surprise, at least one of the females laid a batch of eggs. This second generation of offspring is still alive and apparently healthy to this day, being 26 years old and counting. The oldest tick from the original batch died after 27 years, during which they were deprived of food for eight years.

One explanation is that the female ticks are capable of parthenogenesis, also known as “virgin births” because embryos can grow and develop without fertilization by sperm. But Shepherd thinks this is extremely unlikely. Instead, the females are probably capable of long-term sperm storage until they have ample food, at which point the sperm moves up the reproductive tract and fertilizes eggs.

In any case, both this longevity and long-term storage are records for any species of tick — and these insights could prove useful beyond the remarkable nature of conducting a 60-year experiment. That’s something for other researchers to learn though, as the ticks have been shipped to South Africa for further study, while Shepherd is now moving onto new research on moths and the physiology of their sperm.

“Research on how organisms master such challenges can inform understanding of how other organisms, including us, might manage similar challenges,” Shepherd said.

The findings appeared in the Journal of Medical Entomology.

Novel mRNA vaccine against ticks works in guinea pigs

A group of researchers from Yale University have developed an mRNA vaccine that teaches the immune system to identify saliva from tick bites. The vaccine, which proved to be effective in guinea pigs, could prevent ticks from feeding on and then transmitting tick-borne diseases to people, a growing problem in many countries. 

It's a much bigger problem than you think
Image credit: Creative Commons / Jaqueline Mattias.

The vaccine is based on the same mRNA technology that has proven effective against COVID-19. Essentially, the mRNA shot means being injected with genetic material from the target virus instead of the virus itself. The mRNA gives your body instructions to fight the targeted pathogen and then is eliminated. Researchers have been working on mRNA vaccines, but thanks to the great efforts invested in the current pandemic, we’re finally on the right path. 

“There are multiple tick-borne diseases, and this approach potentially offers more broad-based protection than a vaccine that targets a specific pathogen,” senior author Erol Fikrig and Yale researcher said in a statement. “It could also be used in conjunction with more traditional, pathogen-based vaccines to increase their efficacy.”

Lyme disease is the most famous and damaging of them all tick-borne diseases, but it’s not the only one. Lyme, as well as several other diseases, is expanding across North America and Europe, with about 40,000 reported cases in the US per year. Ticks are a potential danger to anyone outdoors, from farmworkers to hikers, and they transmit several pathogens that can cause serious health problems that can even be life-threatening.

The new vaccine is different from those developed by Valneva and Pfizer and it’s only early stages of development but moving forward. The main difference is that it targets the bacteria responsible instead of the tick carrier. They are both promising approaches that could bring a solution to a growing health concern. 

Developing a vaccine

The researchers at Yale developed a new vaccine that trains the immune system to respond to tick bites, exposing it to 19 proteins found in tick saliva. It has mRNA molecules that tell the cells to produce these proteins – just like the mRNA COVID-19 vaccine tells the cells to manufacture coronavirus proteins to shield against the virus. 

In a set of experiments, the team tested the vaccine on guinea pigs. Unlike unvaccinated animals, vaccinated guinea pigs exposed to ticks developed red rashes at the place where they were bitten, suggesting an immune response. The ticks also tended to detach early on without sucking as much blood as they normally would.

The researchers also placed ticks carrying the Lyme disease on both vaccinated and unvaccinated animals. They removed the ticks once the skin rashes appeared on the animals, something that usually happens in the first 18 hours. While none of the vaccinated guinea pigs became infected, half the unvaccinated animals did.

“The vaccine enhances the ability to recognize a tick bite, partially turning a tick bite into a mosquito bite,” Fikrig said in a statement. “When you feel a mosquito bite, you swat it. With the vaccine, there is redness and likely an itch so you can recognize that you have been bitten and can pull the tick off quickly.”

While the vaccine was successfully in guinea pigs, it wasn’t in mice – unable to get a natural resistance after infection. The researchers now plan to test it in other animals, such as rabbits, so to better understand how the immunity of ticks varies in different hosts, and slowly move on towards humans. They also want to develop in the future vaccines for other tick-borne pathogens.

The study was published in the journal Science Transnational Medicine.

Potentially fatal tick-borne brain disease found in the UK for first time

Tick-borne encephalitis virus (TBEV) has been found in the UK for the first time. The virus has been discovered as part of ongoing research by Public Health England and the Emerging and Zoonotic Infections National Institute for Health Research (NIHR) Health Protection Research Unit at the University of Liverpool.

Experts described the risk of infection as “very low,” but called on members of the public to be aware of ticks, small parasitic arachnids that are related to spiders and mites.

Front. Immunol., 26 September 2018 | https://doi.org/10.3389/fimmu.2018.02174

Tick-borne encephalitis (TBE) virus is an infection that causes no symptoms in most people. However, within one or two weeks of being bitten, some may complain of flu-like symptoms such as headaches, fever, fatigue and joint pain. In approximately one in ten cases, encephalitis or meningitis may follow, leading to severe headaches, light sensitivity, and dizziness, as well as problems with concentration, speech and walking. In rare cases, the virus can cause paralysis in the arms and legs and even death.

The infection is endemic in Scandinavia, mainland Europe, and parts of China and Japan. Ticks live in forests and grassy areas. It has now been detected in Thetford Forest, in eastern England, and the border between the southern counties of Hampshire and Dorset.

Earlier this year a European visitor became ill after being bitten by a tick in the New Forest area. This is a highly probable case of TBE. The patient, who was reported to PHE through the European Early Warning and Response System has since made a full recovery. No further cases in the UK have been identified. In 2017, there were 3,079 reported cases of TBE in Europe, including 9 associated fatalities.

https://www.youtube.com/watch?v=RhWlHsQnncw

The number of infections is increasing in Europe due to climate change and an increase in outdoor leisure pursuits, according to PHE. It is also possible that migratory birds introduced TBE-infected ticks to the UK, or they could have arrived along with pets traveling from endemic countries in Europe to the UK, according to PHE.

“Ticks carry a number of infections including Lyme disease, so we are reminding people to be ‘tick aware’ and take tick precautions, particularly when visiting or working in areas with long grass such as woodlands, moorlands and parks,” said Nick Phin of PHE.

Ticks are most active from May to October, although in some parts of Europe tick season could start as early as February if temperatures rise above 8 degrees Celsius. 

Experts recommend a TBE vaccine if you’re visiting a country where the infection is common and you’re planning to do outdoor activities when you get there. Two injections of the vaccine can protect you for about a year. A third injection can protect you for about 3 years. The first injection should be given at least 1 month before traveling.

Lyme disease remains a far more prevalent tick-borne health risk and health officials recommend that hikers walk on clearly defined paths and avoid brushing against vegetation where ticks may be present. Avoiding deep vegetation and sticking to paths will reduce the risk of tick bites, as will covering your skin and using insect repellants.

In 2018, a US congressional advisory committee said tick-related illnesses had become “a serious and growing threat to public health” and in July the US House of Representatives ordered an investigation into whether the Department of Defense had experimented with ticks and other insects as biological weapons.

Along came Alongshan virus, a new tick-borne disease

Blacklegged Tick.

This is what a blacklegged (deer) tick looks like.
Image credits Fairfax County / Flickr.

Tick-borne diseases, which afflict humans and other animals, are caused by infectious agents (viruses, bacteria, protozoa) transmitted by tick bites. As of 2016, 16 tick-borne diseases of humans have been identified, including Lyme diseasetularemiababesiosis and Rocky Mountain Spotted fever.

A group of patients in Inner Mongolia likely represent the first identified human cases of a new tick-borne illness — the Alongshan virus (ALSV). A description of ALSV, along with associated cases, was recently published in the New England Journal of Medicine. ALSV belongs to the jingmenvirus group in the flavivirus family. The first member of the group was described in 2014 and named the Jingmen tick virus (JMTV) because it was isolated from a tick in Jingmen, China.

In 2017, a 42-year-old woman (the index patient) presented to an Inner Mongolian hospital with a headache, fever, and history of tick bite. The woman showed signs of tick-borne encephalitis virus or TBEV but according to the study’s authors, “neither TBEV RNA nor antibodies against TBEV were detected.”

A total of 86 patients were eventually identified with similar symptoms. The patients were infected with an unknown segmented RNA virus, which the authors named ALSV. There were no deaths and all patients recovered with supportive care and the administration of antimicrobials and antivirals. However, 30 out of 86 (35%) patients experienced coma, which suggests ALSV can cause severe illness.

“Our findings suggest that ALSV may be the cause of a previously unknown febrile disease, and more studies should be conducted to determine the geographic distribution of this disease outside its current areas of identification,” the authors concluded. The authors noted the disease has only been found in Inner Mongolia an autonomous region of northern China and carried by Ixodes persulcatus ticks. Mosquitoes in the area, too, also purportedly carry the disease. It is not currently clear if patients are getting the illness exclusively from ticks or from mosquitoes.

New technologies such as next-generation sequencing have greatly accelerated the pace of discovery of new viruses in a wide range of hosts. In a related commentary, experts from the University of Texas Medical Branch at Galveston wrote, “The nature of ALSV, a unique virus in the family Flaviviridae with a vector that has a wide distribution, should warn us of its potential.”

ALSV is only one of the emerging pathogens that has recently been identified in China, in addition to Huaiyangshan banyangvirus (formerly SFTS virus) and Anaplasma capra. There will be more. The experts noted that a far more cost-effective way to understand the emergence of diseases and mitigate their outbreak is a proactive, real-time surveillance of human populations.

In summer months when tick season is at its height, it is recommended to check for ticks daily, especially under the arms, in and around the ears, inside the belly button, behind the knees, between the legs, around the waist, and on the hairline and scalp and shower soon after being outdoors.

Lyme Disease vaccine set to become available soon, as first trials successfully passed

In an exciting announcement, French drug manufacturer Valneva has announced that they’ve successfully completed their first-ever human trial of a vaccine against the disease. The vaccine, which is reportedly up to 96% effective, might soon be available in the UK and US at a “reasonably low” price.

Ticks really are horrendous creatures — they live in warm, humid vegetation, waiting on unsuspecting creatures to walk by so they can jump on and feed on their blood. To make matters even worse, ticks don’t just suck your blood, they also carry a wide range of pathogens, including viruses, bacteria, and protozoa. Among the disease which ticks can carry, the most feared one is Lyme Disease — and for good reason.

Lyme Disease is one of the most common and widespread vector-borne illnesses in the Northern Hemisphere. After a tick bite, it typically kicks off through an expanding area of redness on the skin, though about one in four people don’t get a rash at all. If untreated, the disease can cause the loss of the ability to move one or both sides of the face, joint pains, severe headaches with neck stiffness, and to top it all off, the symptoms can resurface months or even years later. In some cases, the symptoms can re-emerge even after treatment, so it’s no wonder that Lyme Disease has become so feared.

This is where the new vaccine kicks in. The vaccine typically works by kickstarting the immune system to produce antibodies that attack the bacteria hiding inside the insect, preventing them from entering the human blood. According to trials, the vaccine has been found to be between 71.4% and 96.4% effective.

Things seem to bode well for this vaccine, as there are no significant side effects associated with it so far. The vaccine is available for adults or children as young as 2. After the vaccine is administered first, a booster dose is administered 13 months later, to improve effectiveness.

David Lawrence, Valneva’s chief financial officer, told The Sunday Telegraph that the company was investing £262 million ($350 million) into the development of the vaccine, attempting to make it even more effective, and also making sure that it can be manufactured at a reasonable price.

Valneva’s vaccine candidate, VLA15, is currently the only active vaccine program in clinical development against Lyme disease. The program was closely followed by national and international health bodies, being granted Fast Track designation by the U.S. Food and Drug Administration (FDA) in July 2017.

EDIT: The article was edited to clarify that this is not the first ever Lyme vaccine. In 1998, the FDA approved a new recombinant Lyme vaccine, LYMErix™, which reduced new infections in vaccinated adults by nearly 80%. Just 3 years later, the manufacturer voluntarily withdrew its product from the market amidst media coverage, fears of vaccine side-effects, and declining sales. More information here.

Ixodes tick.

Researchers zero in on Lyme disease’s ability to resurface months after treatment

New research at the University of Maryland (UMD) has uncovered how bacteria that cause Lyme disease survive and persist for months following our body’s immune response.

Ixodes tick.

Ixodes tick as seen under a confocal immunofluorescence microscope.
Image credits Dr. Utpal Pal / University of Maryland.

Throughout his 12 years of work at the UMD, Dr. Utpal Pal has gained a unique understanding of the works of Lyme disease and the bacteria that causes it (spirochete Borrelia burgdorferi). His previous research isolated the protein marker we use to identify when this spirochete infects the body. A new paper from his lab sheds light on one of this bacteria’s scariest and least understood abilities, by describing a protein it produces that disables our bodies initial immune responses. The new study also explains how this bacteria can re-appear in the body weeks after treatment.

When life gives you limes

Borrelia burgdorferi is one of the few pathogens that can persist in the body for long periods of time. In light of this fact, there has been keen interest from the medical community in understanding why and how it does it. Such knowledge would be a major breakthrough for the treatment of tick-borne diseases like Lyme, which is becoming an increasingly prevalent public health issue.

“Most people don’t realize that they actually are walking around with more bacterial cells in their bodies than their own cells, so we are really bags of bacteria,” Pal says. “Most are good, but the second your body detects something that is a pathogen and can cause disease, your immune system starts to work.”

According to Pal, Lyme disease isn’t actually caused by the bacteria, but by your body’s reaction to it. When the infection is first detected, our immune system has to work on incomplete information: it knows something is trying to invade, but not exactly what. So, it sends a versatile, nonspecific wave of attack in a bid to fight off the pathogens before they set up camp. This stage usually takes a few hours to a few days at most.

If unsuccessful, our immune system gets readied for a prolonged conflict. It takes between seven to ten days to gather data on the enemy, finally sending a second, more numerous and highly specialized wave of reinforcement to wipe the floor with whatever pathogens are still alive and kicking.

In the case of Lyme disease, however, this dance doesn’t go according to our body’s schedule. Sometime between six months to a year after traditional antibiotic therapy, many people experience returning, non-objective symptoms of varying intensity for which there is no currently-known treatment (but plenty of bogus ones) — a condition known as Post-Treatment Lyme Disease Syndrome.

Dr. Pal and colleagues found that even in the absence of the protein used to defeat the first attack from our immune systems, the infection can reoccur a few weeks later. This suggests Borrelia, just like our immune system, uses a layered defense strategy, something that has never been observed before — and which could explain what causes chronic cases of Lyme disease.

“[Borrelia burgdorferi] wins the first battle, and your body overreacts so much that it causes intense inflammation in all the joints and areas that the bacteria spreads by sending so many reinforcements to kill it. Borrelia is then killed, but the inflammation remains and causes many of your symptoms for Lyme disease,” Pal explains.

“That is why killing Borrelia in the first wave of immunity is so important.”

According to estimates from the Centers for Disease Control and Prevention (CDC), there are about 300,000 new cases of Lyme disease in the US each year. However, these cases are largely underestimated and reported due to the attention given to mosquito-transmitted diseases like malaria. Pal says that ticks are actually a greater public health concern than people realize: he says “the majority” of vector-borne diseases in the US can be traced back to ticks, with 6 out of the 15 distinct tick diseases (including Lyme) transmitted by the Ixodes tick.

The paper “Plasticity in early immune evasion strategies of a bacterial pathogen” has been published in the journal Proceedings of the National Academy of Sciences.

New ancient tick.

Ancient amber reveals that ticks dined on feathered dinosaurs, too

Ticks are a much more ancient pain than you’d reckon — some 99 million years ago, they were bitting into (and annoying) feathered dinosaurs.

Tick and feather amber.

A tick grasping a dinosaur feather in Myanmar amber.
Image credits Peñalver et al., 2017, Nature Communications.

Dreaded today as vectors of Lime’s disease, ticks have been around for far longer than us humans. Being so ancient, scientists have long wondered what or who these insects dined on before mammals came to be. A recent discovery shows that even the mighty dinosaurs weren’t beyond the reach of this tiny, biting menace.

At least, not feathered dinosaurs.

Snapshot in time

The findings are partially based on amber specimens recovered from Myanmar. While forming, back in the Cretaceous, one of the pieces trapped a tick alongside a dinosaur feather in its hardening resin.

“Amber is fossilized resin, so it’s able to capture small bits of the ecosystem almost instantly,” says lead author Ricardo Pérez-de la Fuente, a research fellow at the Oxford University Museum of Natural History.

“Amber can actually preserve interactions between organisms. This is the case with the feather and the grasping tick.”

The fossilized interaction lends support to a theory that de la Fuente had been previously working on, largely based on other ticks trapped in amber during the same period. They didn’t get to endure the ages alongside feathers, but the bits of amber that enclosed them did contain little hairs, consistent with the type left behind by a type of beetle larva still seen today in birds’ nests.

New ancient tick.

A new species of ancient tick identified by the team.
Peñalver et al., 2017, Nature Communications

So there was evidence in favor of Pérez’s theory, but only of an indirect nature. Finding the feather-and-tick pair provided the link the team needed.

Until now, researchers assumed that ticks dined on early amphibians, reptiles, and the forefathers of modern mammals. Pérez’s theory doesn’t exclude these other types of animals from the menu, especially since feathered dinosaurs weren’t the only animals living in nests at the time, but it does expand on the menu.

Pérez says follow-up research needs to be done to understand how a new species of ancient tick identified in the study, Deinocroton draculi, fits into the bigger tick order Parasitiformes. Furthermore, the finding could help uncover the ancient origins of ticks and their blood-sucking behavior: one tick found in the amber is engorged with blood but the team couldn’t figure out how to analyze it — the tick was only partially encased in amber, so its original chemistry is altered.

The paper “Parasitised feathered dinosaurs as revealed by Cretaceous amber assemblages” has been published in the journal Nature Communications.

Amber discovery shows Lyme disease is older than human race

Lyme disease is a stealthy disease, which can be very dangerous, especially if misdiagnosed. It was only recognized officially 40 years ago, but now, a new amber research has shown that the bacteria causing it may have been around for over 15 million years – long before any human was walking on Earth. The study indicates tick-related illnesses have been around for the entire history of the human race.

Researchers from the Oregon State University (OSU) were studying amber from the Dominican Republic when they came across samples with Borrelia, a type of spirochete-like bacteria that to this day causes Lyme disease. The results were published in Historical Biology.

“Ticks and the bacteria they carry are very opportunistic,” said George Poinar, Jr., a professor emeritus in the Department of Integrative Biology of the OSU College of Science, and one of the world’s leading experts on plant and animal life forms found preserved in amber. “They are very efficient at maintaining populations of microbes in their tissues, and can infect mammals, birds, reptiles and other animals.

In a related study, published in Cretaceous Research, the same team announced the first fossil record of Rickettsial-like cells, a bacteria that can cause various types of spotted fever. The samples they analyzed however were much older – over 100 million years old.

As summer arrives and millions of people start heading for the outdoors, it’s important to be aware of the danger posed by ticks. Given the long period in which the bacteria has been around, researchers think that Lyme disease did much more damage than previously believed – but the diseases was never diagnosed.

“In the United States, Europe and Asia, ticks are a more important insect vector of disease than mosquitos,” Poinar said. “They can carry bacteria that cause a wide range of diseases, affect many different animal species, and often are not even understood or recognized by doctors. It’s likely that many ailments in human history for which doctors had no explanation have been caused by tick-borne disease.”

In 30 years of studying diseases revealed in the fossil record, Poinar has documented the ancient presence of such diseases as malaria, leishmania, and others. The oldest documented case of Lyme disease is the Tyrolean iceman, a 5,300-year-old mummy found in a glacier in the Italian Alps.

“Before he was frozen in the glacier, the iceman was probably already in misery from Lyme disease,” Poinar said. “He had a lot of health problems and was really a mess.”

Interestingly enough, at a 1909 research conference, Swedish dermatologist Arvid Afzelius presented a study about an expanding, ring-like lesion he had observed in an older woman following the bite of a sheep tick. He named the lesion erythema migrans – but it wasn’t until 1975 that the disease was properly identified and started being treated. Still, numerous cases are misdiagnosed even today. If you are bitten by a tick, be sure to visit your doctor!

Journal References: George Poinar. Spirochete-like cells in a Dominican amberAmbylommatick (Arachnida: Ixodidae). Historical Biology, 2014; 1 DOI: 10.1080/08912963.2014.897699
George Poinar. Rickettsial-like cells in the Cretaceous tick, Cornupalpatum burmanicum (Ixodida: Ixodidae). Cretaceous Research, 2014; DOI: 10.1016/j.cretres.2014.02.007

Tick bite helps spread vegetarianism

What would you like with your burger? Some anaphylaxis, maybe? No? How about nausea, stomach cramps, indigestion, vomiting, diarrhea, congestion, sneezing, headaches or asthma? If this would happen to me, I would definitely say pass.

What does this have to do with a tick or with anything for that matter, one might ask. As it turns out, if you get bitten by a lone star tick, you have a good chance of developing what is called “alpha-gal allergic reaction” – which thankfully, doesn’t mean you’ll become allergic to girls, but sadly, means you will become allergic to a sugar carbohydrate found in red meats.

If you get bitten by this tick antibodies to alpha-gal in the tick’s saliva are produced in the person’s blood. Your body of course starts attacking the carbohydrate and remembers it as a bad thing, therefore it will attack it every time it sees it – including the one from meat.

“Blood levels of antibodies for alpha-gal in the human body can rise after a single bite from the lone star tick,” said allergist Stanley Fineman, M.D., ACAAI president. “This can result in allergic symptoms which are usually delayed after meat ingestion and may present as mild hives but may also be a severe, potentially deadly reaction known as anaphylaxis.”

The tick may be small, but it’s leaving quite a footprint. According to researchers, positive alpha-gal rates are 32 percent higher in the central and southern regions of the United States, which is lone star tick territory.

“These findings suggest that other species of ticks, or possibly human factors, may play a role in allergic reactions to alpha-gal,” said Fineman. “Patients with delayed allergic reactions after eating meats should see an allergist to determine if it is an alpha-gal allergy. The best treatment is strict avoidance of meat.”

So cows and pigs rejoice, hamburger sales go down, veggie sales go up… sounds like a good thing to me.