Ticks Spread Plenty More for You to Worry About Beyond Lyme Disease
By Jerome Goddard
When it comes to problems caused by ticks, Lyme disease hogs a lot of the limelight. But various tick species carry and transmit a collection of other pathogens, some of which cause serious, even fatal, conditions.
In fact, the number of tick-borne disease cases is on the rise in the U.S. The range where various species of ticks live in North America may be expanding due to climate change. Researchers continue to discover new pathogens that live in ticks. And new, invasive tick species keep turning up.
In my career as a public health entomologist, I've been amazed at the ability of ticks to bounce back from all the ways people try to control them, including with pesticides. Ticks excel at finding new ecological niches for survival. So people and ticks frequently cross paths, exposing us to their bites and the diseases they carry.
Here are some of the lesser-known, but growing, threats from ticks.
Ticks Can Spread Bacterial Diseases
Certain very small species of bacteria that can cause human diseases, such as rickettsia, ehrlichia and anaplasma, live in ticks. Ticks ingest these bacteria when they drink animals' blood. Then when the ticks take a subsequent blood meal, they pass the bacteria along to the next animal or person they feed on.
Probably the most well known of these bacterial diseases is Rocky Mountain spotted fever, the most frequently reported rickettsial disease in the U.S., with about 6,000 cases each year. The number of diagnoses seems to be increasing nationwide, especially among Native Americans, probably due to exposure on reservations to free-roaming dogs that can carry ticks.
Rocky Mountain spotted fever usually comes with a rash, as on this child.
Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases (NCIRD), CC BY
When people get sick with Rocky Mountain spotted fever, they usually come to a clinic with three things: fever, rash and history of tick bite. They may also report severe headache, chills and muscle pains, and gastrointestinal symptoms such as abdominal pain and diarrhea. A skin rash is usually present after a few days, but not always. Mental confusion, coma and death can occur in severe cases. Untreated, the mortality rate is about 20%; and even with treatment, 4% of those infected die.
Not all tick species are effective transmitters of the rickettsia bacteria. Even within the vector species, often only 1% to 5% of ticks in an area are infected. So getting bitten by a tick that passes rickettsia bacteria on to you is like getting stuck with a needle in a haystack. The primary carriers are the American dog tick in the eastern U.S. and Rocky Mountain wood tick in the West. The brown dog tick has also recently been shown to be a vector.
In most tick-borne diseases, the tick needs to feed for some amount of time before any pathogens it is carrying are transmitted to the animal whose blood it is eating. Rocky Mountain spotted fever organisms generally take between one and three hours for transmission to occur, so attached ticks need to be removed quickly. Doctors usually prescribe the antibiotic doxycycline to treat Rocky Mountain spotted fever, which works quite well if the disease is recognized early.
Ehrlichiosis is another bacterial disease transmitted from ticks to people. In the U.S. it's most commonly caused by Ehrlichia chaffeensis bacteria, carried by lone star ticks which are common in the eastern U.S. Ehrlichia bacteria infect a type of blood cell called leukocytes. Human monocytic ehrlichiosis occurs mostly in the southern and south-central U.S.; 1,642 cases were reported to the CDC in 2017.
Ehrlichiosis patients usually have fever, headache, muscle aches and a progressive low white blood cell count. As opposed to Rocky Mountain spotted fever, people get a rash only about 20% to 40% of the time. Doctors usually treat ehrlichiosis with doxycycline.
Another tick-borne bacterial disease to worry about is human granulocytic anaplasmosis. In human granulocytic anaplasmosis, Anaplasma phagocytophilum bacteria infects a type of white blood cell called granulocytes. It mostly occurs in the upper midwestern and northeastern U.S., and the incidence is increasing, with 5,762 cases of human granulocytic anaplasmosis reported to the CDC in 2017.
Symptoms include fever, headache, muscle aches and progressive low white blood cell count. It's the deer tick Ixodes scapularis — famously also responsible for Lyme disease — that transmits the Anaplasma bacteria to humans. There's the unlucky chance that a bite from a deer tick could infect you with both diseases. Again, recommended therapy is doxycycline.
A female Ixodes scapularis tick.
Dr. Blake Layton, MSU, CC BY-ND
Ticks Can Carry Viruses, Too
People usually think of mosquitoes when they think of insect-transmitted viruses – dengue, Zika or West Nile garner a lot of headlines. But ticks can transmit viruses, too.
Scientists have historically grouped tick-borne viral diseases into two categories. One is diseases similar to dengue fever. The main dengue-like viral disease transmitted by ticks in the U.S. is Colorado tick fever, which occurs in mountainous areas of the West.
The other group of tick-borne diseases resemble mosquito-borne encephalitis. Most of these illnesses, characterized by brain inflammation, are not found in the U.S. Powassan encephalitis is the one that is, occurring in the northeastern U.S. and adjacent regions of Canada.
Powassan is a relatively rare but serious human disease, characterized by sudden onset of fever with temperature up to 104 degrees Fahrenheit, along with convulsions. Brain inflammation is usually severe, with vomiting, respiratory distress and prolonged fever.
Fewer than 100 cases of Powassan have been reported in North America, with about half of them fatal. Its incidence seems to be increasing; there were 34 cases of Powassan reported during 2017. POW is maintained in a natural cycle when ticks — primarily Ixodes cookei — infect animals with the virus via their bites. Then these infected animals may serve as what scientists call disease reservoirs, infecting new ticks when they feed on their blood.
Tiny larval lone star ticks next to a penny.
In the last decade, researchers have found additional new tick-borne viruses in the U.S. About 30 cases of Heartland virus have thus far been identified. It's associated with the lone star tick and has been recognized in Missouri, Oklahoma, Kentucky and Tennessee.
A few cases of a new Thogotovirus called Bourbon virus have been identified in the Midwest and southern U.S. The lone star tick may be the vector of Bourbon virus as well.
A Food Allergy Triggered by a Tick Bite
Maybe the most bizarre threat from ticks is the "red meat allergy" scientists have recently traced back to tick bites. People can become allergic to eating meat when a tick's saliva passes on the carbohydrate galactose-α-1.3-galactose it had previously picked up in a blood meal from an animal. If prone to allergies, the person can get sensitized to that alpha-gal molecule that's found in animal blood and other tissues.
Then days or weeks later, he or she may develop hives, swollen skin and lips, or even life-threatening anaphylactic shock three to six hours after eating red meat. Meats containing alpha-gal include beef, pork, lamb, squirrel, rabbit, horse, goat, deer, kangaroo, seal and whale. People who become sensitized to alpha-gal may still eat chicken, turkey and fish.
Overall, people should be aware of what tick-borne diseases are present in their area and use personal protection techniques whenever outdoors in tick-infested areas. Remember that ticks often come into close contact with people via pet dogs or cats. It's a good idea to inspect yourself for ticks after being outdoors in tick-infested areas. Reducing the number of tick bites and the amount of time ticks remain attached can go a long way to protecting you from tick-borne diseases.
Invasive Tick Spreads to Ninth State, CDC Warns of 'New and Emerging Disease Threat' https://t.co/9r4yqpJvxJ— EcoWatch (@EcoWatch) December 3, 2018
Jerome Goddard is an extension professor of biochemistry, molecular biology, entomology and plant pathology at Mississippi State University.
Disclosure statement: Jerome Goddard does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond his academic appointment.
Reposted with permission from our media associate The Conversation.
- Ticks and Mosquitoes Bringing More Diseases—What Can We Do ... ›
- CDC Official Warns Warmer Earth Means More Insect-Borne Diseases ›
- Lyme Disease Symptoms Could Be Mistaken for COVID-19 ›
EcoWatch Daily Newsletter
A herdsman in the Chinese autonomous region of Inner Mongolia was diagnosed with the bubonic plague Sunday, The New York Times reported.
- Plagues Follow Bad Leadership in Ancient Greek Tales - EcoWatch ›
- Black Death Is Back! Two Cases of Plague Confirmed in China ... ›
By Matt Kasson, Brian Lovett and Carolee Bull
Home gardening is having a boom year across the U.S. Whether they're growing their own food in response to pandemic shortages or just looking for a diversion, numerous aspiring gardeners have constructed their first raised beds, and seeds are flying off suppliers' shelves. Now that gardens are largely planted, much of the work for the next several months revolves around keeping them healthy.
Start With Prevention<p>Just as preventive steps like maintaining a balanced diet help keep humans healthy, home growers can take many actions to help their gardens thrive.</p><p>One key step is assessing soil fertility – the ability of soil to sustain plant growth – which can vary widely depending on your location and soil type. Low soil fertility limits food production and predisposes plants to disease and pests. University extension <a href="https://soiltesting.wvu.edu/" target="_blank">soil testing labs</a> can help evaluate the quality of garden soil and identify nutrient deficiencies and acidic soils, often at no charge.</p>
Using weed barrier landscape cloth for planting rows and mulching between rows is an effective way to suppress weeds. Matt Kasson, CC BY-ND
Diagnosing Problems<p>Common plant pathogens include <a href="https://www.apsnet.org/edcenter/disandpath/viral/introduction/Pages/PlantViruses.aspx" target="_blank">viruses</a>, <a href="https://www.apsnet.org/edcenter/disandpath/prokaryote/intro/Pages/Bacteria.aspx" target="_blank">bacteria</a>, <a href="https://www.apsnet.org/edcenter/disandpath/nematode/intro/Pages/IntroNematodes.aspx" target="_blank">nematodes</a>, <a href="https://www.apsnet.org/edcenter/disandpath/oomycete/introduction/Pages/IntroOomycetes.aspx#:%7E:text=The%20oomycetes%2C%20also%20known%20as,foliar%20blights%20and%20downy%20mildews." target="_blank">oomycetes</a> and <a href="https://www.apsnet.org/edcenter/disandpath/fungalasco/intro/Pages/IntroFungi.aspx" target="_blank">fungi</a>. All of these microorganisms, especially at an early stage of infection, are too small to see. But when they proliferate, they cause changes in plants that we can recognize.</p><p>Unlike insects, which move around on six legs or on wings through the air, pathogens can move unseen and unchecked from leaf to leaf on the wind, through the soil or in droplets of water. Some microbes have even formed intimate relationships with insects and use them as vehicles to move from plant to plant, which makes these pathogens even more challenging to manage. Unfortunately, by the time some pathogens make their presence known, the damage is already done.</p><p>We recently conducted a <a href="https://twitter.com/kasson_wvu/status/1265989041725624323" target="_blank">Twitter poll</a> of gardeners nationwide to find out which culprits plagued their gardens. People named <a href="https://ento.psu.edu/extension/factsheets/aphids" target="_blank">aphids</a>, <a href="https://ento.psu.edu/extension/factsheets/squash-vine-borer" target="_blank">squash vine borers</a>, <a href="https://ento.psu.edu/extension/factsheets/squash-bug" target="_blank">squash bugs</a> and <a href="https://ento.psu.edu/extension/factsheets/flea-beetle" target="_blank">flea beetles</a> as the most problematic insect pests. Their most troublesome pathogens included <a href="https://extension.wvu.edu/lawn-gardening-pests/plant-disease/fruit-vegetable-diseases/powdery-mildew" target="_blank">powdery mildew</a>, <a href="https://plantpath.ifas.ufl.edu/rsol/Trainingmodules/BWTomato_Module.html" target="_blank">tomato bacterial wilt</a> and <a href="https://extension.wvu.edu/lawn-gardening-pests/plant-disease/fruit-vegetable-diseases/downy-mildew" target="_blank">cucurbit downy mildew</a>.</p><p>To manage such perennial challenges, the first step is to spend time closely looking at your plants. Do you notice any insects consistently hanging around, or molds colonizing leaves or other plant parts? How about symptoms such as blight, stunting, or leaves that are yellowing, browning or wilting?</p>
This white fungal growth is an early sign of powdery mildew on a leaf of susceptible summer squash. Matt Kasson, CC BY-ND
- 5 Ways to Make Your Garden Regenerative - EcoWatch ›
- How to Make your House and Garden More Tranquil - EcoWatch ›
- Gardening in Hard Times Has Deep History - EcoWatch ›
By Emma Charlton
The effects of climate change may more far-reaching than you think.
Hotter temperatures have been linked to a rise in energy poverty, with more people struggling to meet their energy bills from their household income, according to a new study published on ScienceDirect by researchers from Italy's Ca' Foscari University.
Value of air conditioning imports in selected OECD countries. ScienceDirect
The ‘Golden Thread’<p>The <a href="https://www.endenergypoverty.org/reports" target="_blank">Global Commission to End Energy Poverty</a> calls access to energy the "golden thread" that weaves together economic growth, human development, and environmental sustainability. And one of the <a href="https://www.weforum.org/agenda/archive/sdg-07-affordable-and-clean-energy" target="_blank">United Nations' Sustainable Development Goals</a> is to ensure access to affordable, reliable, sustainable and modern energy for all by 2030.</p><p>Sustainability also has a large role to play in the future of energy and failing to embed green policies in COVID-19 stimulus packages and underinvesting in green infrastructure are current risks, according to the <a href="http://www3.weforum.org/docs/WEF_COVID_19_Risks_Outlook_Special_Edition_Pages.pdf" target="_blank">World Economic Forum</a>.</p><p>In its vision for a 'Great Reset' – building a better world after the pandemic – the Forum and the IMF jointly backed the <a href="https://www.weforum.org/agenda/2020/06/end-fossil-fuel-subsidies-economy-imf-georgieva-great-reset-climate/" target="_blank">transition to a green economy</a> and called for an end to fossil fuel subsidies.</p>
As if the surging cases of coronavirus weren't enough for Floridians to handle, now the state's Department of Health (DOH) has confirmed that a person in the Tampa area tested positive for a rare brain-eating amoeba, according to CBS News. The Florida DOH posted a warning to residents to remind them of the dangers of the rare single-celled amoeba that attacks brain tissue.
Scientists are urging the WHO to revisit their coronavirus guidance to focus more on airborne transmission and less on hand sanitizer and hygiene. John Lund / Photodisc / Getty Images
The World Health Organization (WHO) is holding the line on its stance that the respiratory droplets of the coronavirus fall quickly to the floor and are not infectious. Now, a group of 239 scientists is challenging that assertion, arguing that the virus is lingering in the air of indoor environments, infecting people nearby, as The New York Times reported.
- Summer Heat Won't Kill the Coronavirus, New Study Says - EcoWatch ›
- Here's Why COVID-19 Can Spread So Easily at Gyms and Fitness ... ›
- Is the New Coronavirus Airborne? A Study From China Finds Evidence ›
Along the northern shores of the Gulf of Mexico, oysters live in coastal estuaries where saltwater and freshwater meet and mix.
- Hurricanes, Water Wars Threaten New High-End Oyster Industry on ... ›
- 'Dead Zone' Predicted for Gulf of Mexico ›
- The Gulf Oyster Situation Is Very Bad, But There's Hope - EcoWatch ›
Scores of people remained stranded in southern Japan on Sunday after heavy rain the day before caused deep flooding and mudslides that left at least 34 people confirmed or presumed dead.
Care Home Inundated<p>Altogether 16 residents at an elderly care home in Kuma Village are presumed dead after the facility was flooded by water and mud.</p><p>Fifty-one other residents have been rescued by boats and taken to hospitals for treatment, officials said.</p><p>Eighteen other people elsewhere have been confirmed dead, while more than a dozen others were still missing as of Sunday afternoon.</p><p>The Fire and Disaster Management Agency said many others were still waiting to be rescued from other inundated areas.</p><p>Hitoyoshi City was also badly affected by flooding, as rains in the prefecture exceeded 100 millimeters (4 inches) per hour at their height.</p>
More Rain Forecast<p>The disaster in the Kumamoto prefecture on Kyushu island is the worst natural catastrophe since Typhoon Hagibis in October last year, which cost the lives of 90 people.</p><p>Although residents in Kumamoto prefecture were advised to evacuate their homes following the downpours on Friday evening into Saturday, many people chose not to leave for fear of contracting the coronavirus.</p><p>Officials say, however, that measures are in place at shelters to prevent the transmission of the disease.</p><p>More rain is predicted in the region, and the Japan Meteorological Agency has warned of the danger of further mudslides.</p>
- 900,000 Forced to Evacuate Due to Flooding in Japan - EcoWatch ›
- Typhoon Slams Into Flood-Ravaged Japan - EcoWatch ›
- Historic Floods in Japan Kill More Than 100, Force Millions to Flee ... ›