Static electricity attracts ticks to hosts

Ticks can be attracted across air gaps several times larger than themselves by the static electricity that their hosts naturally accumulate, researchers at the University of Bristol have discovered.

This likely greatly increases their efficiency at finding hosts to parasitise because ticks are not capable of jumping, and therefore this is the only mechanism by which they would be able to make contact with hosts that are beyond the reach of their tiny legs.

The findings, published today in Current Biology, are the first known example of static electricity being implicated in the attachment of an animal to another animal.

Ticks carry a lot of nasty diseases, including Lyme disease, that make many people's and animal's lives miserable, and can even cause death. Therefore there is a huge social and economic benefit to trying to reduce the ability of ticks to attach onto people and the animals humans rely upon.

Lead author Sam England from Bristol's School of Biological Sciences explained: "We knew that many animals, including humans, can accumulate quite significant electrostatic charges.

"We see this when we get a static shock after bouncing on a trampoline, or when rubbing a balloon on our hair, for example. But this electrostatic charging also happens to animals in nature when they rub against objects in their environment like grass, sand, or other animals. These charges are surprisingly high, and can be equivalent to hundreds if not thousands of volts -- more than you get out of your plug sockets at home! Importantly, static charges exert forces on other static charges, either attractive or repulsive depending whether they are positive or negative.

"We wondered whether the static charges that mammals, birds, and reptiles naturally accumulate could be high enough that parasitic ticks could be lifted through the air by electrostatic attraction onto these animals, therefore improving their efficiency at finding hosts to feed on."

The team initially tested the idea by bringing statically charged rabbit fur and other materials close to ticks and observing whether they were attracted to them.

They witnessed the ticks being readily pulled through the air across air gaps of several millimetres or centimetres (the equivalent of humans jumping up several flights of stairs) by these charged surfaces, and so investigated further.

Sam continued: "First, we used previous measurements of the typical charge carried by animals to mathematically predict the strength of the electric field that is generated between a charged animal and the grass that ticks like to sit on and wait for hosts to pass by.

"Then, we placed ticks underneath an electrode, with an air gap in between, and increased the charge on the electrode until the ticks were attracted onto the electrode. By doing this we were able to determine the minimum electric field strength at which the ticks could be attracted. This minimum electric field was within the order of magnitude predicted by the mathematical calculations of the electric field between a charged animal and grass, therefore it is likely that ticks in nature are attracted onto their hosts by static electricity."

There are several wider implications and potential applications to these findings. Firstly, the phenomenon likely applies to many other parasitic species that want to make contact and attach to their hosts, such as mites, fleas, or lice, and so it could be a universal mechanism for animals to make contact with and attach onto each other.

Beyond the purely scientific implications, the discovery opens the door for new technologies to be developed to minimise tick bites in humans, pets, and farm animals, such as developing anti-static sprays.

Sam concluded: "We have now discovered that ticks can be lifted across air gaps several times larger than themselves by the static electricity that other animals naturally build up. This makes it easier for them to find and attach onto animals that they want to latch onto and feed from. Until now, we had no idea that an animal could benefit from static electricity in this way, and it really opens up one's imagination as to how many invisible forces like this could be helping animals and plants live their lives."

Read more at Science Daily

Study demonstrates that ticks weaken skin's immune response

Hitherto, scientists have not fully understood why ticks are such dangerous disease vectors. A research team led by Johanna Strobl and Georg Stary from MedUni Vienna's Department of Dermatology shows that tick saliva inhibits the skin's defence function, thereby increasing the risk of diseases such as tick-borne encephalitis (TBE) or Lyme disease. The study was recently published in the Journal of Clinical Investigation.

The researchers carried out their investigations on skin samples from volunteers and also on models of human skin, mimicking the bite of the most common European tick (Ixodes ricinus). In both cases, the team led by Georg Stary (MedUni Vienna's Department of Dermatology, CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases) in collaboration with the research group of Hannes Stockinger (Center for Pathophysiology, Infectiology and Immunology at MedUni Vienna) identified rapidly occurring patterns of immunomodulation. For example, it was found that the function of immune cells, especially T cells, which are important for immunological memory, was disrupted by contact with tick saliva.

Tick saliva modulates immune system

The scientists made similar observations in early stages of model infection by Borrelia burgdorferi, the most common cause of Lyme disease. They found that pre-incubation of Lyme disease-transmitting bacteria (B. burgdorferi spirochetes) with tick salivary gland extracts impedes the accumulation of immune cells in the skin and increases the pathogen burden. "Overall, we found that tick feeding causes profound changes in the skin's immune system inhibiting the local immune response. This means that dangerous pathogens that are introduced into the skin together with tick saliva, can multiply more easily, leading to infection," says Johanna Strobl, lead author of the study, summarising the main research findings.

Climate change increases danger from ticks

Austria is one of the countries with the greatest prevalence of ticks. Nearly every second European tick is infected with pathogens, Lyme disease and tick-borne encephalitis (TBE) being the most common tick-borne diseases. The arachnids become active at a temperature of seven degrees. Due to rising temperatures associated with climate change, ticks now also pose a threat in higher-altitude regions of Austria and well into late autumn.

Read more at Science Daily

Longhorned tick discovered in northern Missouri

The Longhorned tick causes the loss of millions of dollars in agricultural revenue to cattle producers worldwide, and it is now in northern Missouri.

Originally found in eastern Russia and the Australasian region, this tick was first found in the United States in 2017 in New Jersey. It has since reached the Mid-Atlantic, New England and Midwestern regions of the U.S., and now has been discovered in northern Missouri for the first time by researchers at the University of Missouri.

Last year, the Longhorned tick was found in the southern part of the state. This latest discovery indicates an additional economic burden to cattle producers due to ticks; as the Longhorned tick infestation could lead to significant loss in weight gain for cattle, similar to an already widely prevalent disease called anaplasmosis; but so far, the threat from this species of tick to cattle -- and people and their pets -- in Missouri remains low. However, researchers emphasize that the discovery of the Longhorned tick in the state increases the need for more vigilance towards ticks in general.

While most ticks reproduce traditionally, female Longhorned ticks can lay thousands of eggs without the help of a male, which makes it easier for them to quickly establish in new areas. Infestation of the Longhorned tick can lead to possible transmission of bovine theileriosis, a disease that kills red blood cells in cattle.

While there have currently not been any confirmed cases of bovine theileriosis in Missouri cattle, this discovery further heightens the need for Missouri cattle ranchers to make informed decisions regarding quarantining protocols when introducing new cattle into their herds in an effort to protect the health of their livestock, which has significant economic implications.

"Studying the prevalence of invasive ticks in different geographical regions can help veterinarians and farmers take proactive, preventative steps that may ultimately protect the health of livestock, which has huge economic implications," said Rosalie Ierardi, an anatomic pathologist at the MU College of Veterinary Medicine who recently discovered two Longhorned ticks in Linn County, Missouri, while conducting anaplasmosis surveillance research.

Ierardi collaborated on the project with Ram Raghavan, a professor in the MU College of Veterinary Medicine and MU School of Health Professions. Raghavan, who has been tracking the spread of various species of ticks in the U.S. for 15 years, predicted the potential geographic distribution of the Longhorned tick back in 2019. So far, the tick appears to be establishing in the areas that he had predicted in that study. He said there not only appears to be an increase in the abundance of all ticks in the Midwest in the past decade, but also an increase in the pathogens and diseases they transmit to cattle, humans and pets.

"Warmer temperatures in the Midwest seem to be creating perfect conditions for ticks and the pathogens they carry to thrive, and this problem may get worse going forward as the planet continues to warm, which is concerning," Raghavan said. "We must be vigilant and devote resources toward trying to prevent these ticks from spreading diseases that harm the health of cattle, humans and their pets. The discovery of Longhorned ticks in northern Missouri greatly increases the need for more vigilance towards ticks in general and the need for routine monitoring of the pathogens they transmit."

Ierardi encourages cattle ranchers who notice weakness, jaundice and pregnancy loss in their cattle to contact their local veterinarian and the MU Veterinary Medical Diagnostic Laboratory for assistance with tracking down the causes for such signs.

Read more at Science Daily