What Tick Saliva Does to the Human Body, Atlantic, July 25, 2019Ticks use saliva to manipulate the body of their hosts so their bites stay painless, itchless, and as unobtrusive as a bug swelling with blood can be. Scientists have since cataloged more than 3,500 proteins from the saliva of various tick species.
When a tick starts to feed, it secretes enzymes in its saliva that destroy a small ring of host tissue. This creates a “feeding cavity,” which Ribeiro likens to a “lake of blood.” “The tick sucks blood from that lake,” he says. For this strategy to work though, ticks also need to make proteins that prevent blood from clotting, as it normally wants to do in an injury site. Over the course of days, a host’s body will try to heal the wound by sending cells that make collagen. Normally, this would allow the wound to scar over, but tick saliva has molecules to counteract this, too.
Lastly, the tick has to evade a host’s immune system. Mammals have complex immune systems with multiple lines of defense, and tick saliva can neutralize pretty much all of them. To start, ticks secrete molecular “mops,” which bind to and neutralize histamine. Histamine is best known for causing itching and redness, but it also plays an important role in opening up blood vessels to allow immune cells to get to a site of injury. Tick saliva prevents this, so tick bites don’t itch and immune cells can’t get to the bite. Tick saliva also degrades pain-inducing molecular signals in a host. That’s why tick bites also do not hurt. Ticks then inject molecules that neutralize or evade a suite of white blood cells that would otherwise be eating or attacking an invader.
Tick-Borne Disease: Working Group Supported by the U.S. Department of Health and Human Services, 2018 Report to Congress, Nov 2018The Tick-Borne Disease Working Group was established by Congress in 2016 as part of the 21st Century Cures Act to provide subject matter expertise and to review federal efforts related to all tick-borne diseases, to help ensure interagency coordination and minimize overlap, and to examine research priorities. The focus of this effort is the development of a report to the Secretary of Health and Human Services and Congress on the findings and any recommendations of the Working Group for the federal response to tick-borne disease prevention, treatment and research, as well as how to address gaps in these areas.
Tick Check, New Yorker, Aug 27, 2018Ticks wait in the grass and the leaves with their legs outstretched, ready to attach to a passing host, burrow into the host’s skin, and feed on the host’s blood while transmitting disease through their saliva, often within a few hours of contact. Kids are particularly vulnerable to ticks because of their exposure to the outdoors, so get in the habit of checking them every ten minutes. More if they’re yours. The elderly, too, are highly susceptible to the diseases transmitted by ticks, simply because they no longer have the strength to argue with Medicare.
An Invasive New Tick Is Spreading in the U.S., New York Times, Aug 6, 2018Although domestic American ticks are a growing menace and transmit a dozen pathogens, no long-horned ticks here have yet been found with any human diseases. In Asia, however, the species carries a virus that kills 15 percent of its victims. In East Asia, long-horned ticks do carry pathogens related to Lyme and others found in North America. But the biggest threat is a phlebovirus that causes S.F.T.S., for severe fever with thrombocytopenia syndrome.
Tickborne diseases are likely to increase, say NIAID officials, Medical XPress, July 26, 2018Bacteria cause most tickborne diseases in the United States, with Lyme disease representing the majority (82 percent) of reported cases. Tickborne virus infections are also increasing and could cause serious illness and death. For example, Powassan virus (POWV), recognized in 1958, causes a febrile illness that can be followed by progressive and severe neurologic conditions, resulting in death in 10 to 15 percent of cases and long-term symptoms in as many as 70 percent of survivors. Only 20 U.S. cases of POWV infection were reported before 2006; 99 cases were reported between 2006 and 2016.
Tickborne Diseases — Confronting a Growing Threat, New England Journal of Medicine, July 25, 2018According to the Centers for Disease Control and Prevention (CDC), the number of reported cases of tickborne disease has more than doubled over the past 13 years.1 Bacteria cause most tickborne diseases in the United States, and Lyme disease accounts for 82% of reported cases, although other bacteria (including Ehrlichia chaffeensis, Anaplasma phagocytophilum, and Rickettsia rickettsii) and parasites (such as Babesia microti) also cause substantial morbidity and mortality. Patterns of spirochete enzootic transmission are geographically influenced and involve both small-mammal reservoir hosts, such as white-footed mice, and larger animals, such as white-tailed deer, which are critical for adult tick feeding. The rising incidence and expanding distribution of Lyme disease in the United States are probably multifactorial, but increased density and range of the tick vectors play a key role. The geographic range of I. scapularis is apparently increasing: by 2015, it had been detected in nearly 50% more U.S counties than in 1996.
This Scary New Report Shows How Unprepared We Are to Fight Tick- and Mosquito-Borne Diseases, MotherJones.com, May 4, 2018William K. Reisen, an emeritus medical entomology professor in the School of Veterinary Medicine at the University of California-Davis, points out that because insect control efforts are often funded by property taxes, sparsely populated areas are particularly hard hit. “For West Nile virus, some of the highest incidence is in the Dakotas—well, no one lives there hardly,” he says. “So it’s hard to get the money to control those mosquitoes.”
The federal government has stepped up its efforts in the last few years. In 2016, Congress authorized the CDC to use an additional $350 million to fight the mosquito-borne Zika virus—the agency used some of that money the following year to launch five new research centers to study vector-borne diseases. Congress also established the Tick-Borne Disease Working Group in 2017. West Nile hospitalizations have cost nearly $800 million since 1999.
No one really knows exactly how much vector-borne illnesses cost the nation, because so many cases go unreported. But CDC spokesman Benjamin Haynes told me the annual estimated cost for Lyme tests alone is about $492 million. Since 1999, he added, the costs associated with hospitalizing people sickened by West Nile are estimated at $778 million. Yet in 2018, the budget for CDC’s Division of Vector-Borne Diseases is less than $50 million, with $10.6 million of that dedicated to Lyme disease.
Are we ready for an epidemic this summer?, Washington Post, May 4, 2018The CDC’s key findings: The number of Americans infected with such diseases, including Zika, West Nile and Lyme, has more than tripled in a decade, jumping from about 30,000 cases a year in 2006 to almost 100,000 in 2016. This total includes nine types of infections never before seen in the United States, including Zika and chikungunya. Looking ahead, 80 percent of state and local health departments are not ready for the insect-borne threat we are facing in just a few weeks.
Diseases from tick, mosquito, flea bites have tripled, BizWomen, May 4, 2018Mosquitos, ticks and fleas are “vectors” that can spread pathogens like dengue, Zika, Lyme disease or plague through their bite. The CDC reported more than 640,000 cases of these diseases in the period studied as well as the introduction or discovery of nine new germs, including the first outbreaks of Zika and Chikungunya in the United States. Peterson, director of the Division of Vector-Borne Diseases, said reforestation has led to an increase in the deer population and consequentially the population of deer ticks, which carry Lyme disease.
TICKBORNE DISEASES OF THE UNITED STATES: A Reference Manual for Health Care Providers, CDC, 2017Anaplasmosis, Babesiosis, Ehrlichiosis, Lyme Disease, Rocky Mountain Spotted Fever, Tularemia. Ticks are generally found near the ground, in brushy or wooded areas. They can’t jump or fly. Instead, they climb tall grasses or shrubs and wait for a potential host to brush against them. When this happens, they climb onto the host and seek a site for attachment.
53 Members Named to Serve on Working Group Subcommittees (Tick-borne Disease), HHS.gov, Feb 6, 2018The Department of Health and Human Services (HHS) announces the names of 53 individuals who have been selected to serve on one of six subcommittees of the Tick-Borne Disease Working Group (Working Group).
Deer-Targeted Methods: A Review of the Use of Topical Acaricides for the Control of Ticks on White-Tailed Deer, Journal of Integrated Pest Management, July 17, 2017White-tailed deer, Odocoileus virginianus (Zimmermann), are a major host for the adult stage of the blacklegged tick, Ixodes scapularis Say, and lone star tick, Amblyomma americanum L. The resurging population of deer in the twentieth century is linked to the emergence of multiple tick-borne pathogens associated with these and other tick species, particularly Lyme disease. Acaricides and parasiticides have long been the principal method for controlling ticks on domestic livestock, applied either topically or orally. The use and development of oral ivermectin and the passive topical treatment deer feeding station called the 4-poster for the control of the blacklegged tick on white-tailed deer is reviewed.
A single tick bite could put you at risk for at least 6 different diseases, Business Insider, June 25, 2016The broad range of potential conditions means that doctors don’t even necessarily know what to look for. Even worse, “ticks can frequently be co-infected with more than one pathogen,” says Tokarz. That’s especially true in certain locations, like on Long Island. One bite could transmit both Lyme disease and babesiosis, conditions that would normally be treated quite differently.
CDC warns against ticks, Lyme disease, Washington Times, June 1, 2017Most of us know that ticks are small insects (arachnids) that bite to fasten themselves onto the skin of an animal or human – and feed on blood. When an infected tick bites a person or an animal, the tick’s saliva transmits infectious agents — bacteria, viruses, or parasites — that can cause illness. They include: Lyme disease bacteria, Babesia protozoa, Anaplasma, Ehrlichia, and other rickettsia, even encephalitis-causing viruses, and possibly Bartonella bacteria. While “back in the day,” tick bites were more of an annoyance, today a bite is much more likely to make you sick and can even change your life!
Senators seek status of Tick-borne Diseases Working Group, LymeDisease.org, April 20, 2017In a letter today to Health and Human Services Secretary Thomas E. Price, U.S. Senators Richard Blumenthal (D-Conn.) and Kirsten Gillibrand (D-N.Y.) sought an update on efforts to form a Tick-Borne Disease Working Group as required by the 21st Century Cures Act. The Act requires HHS to support research related to tick-borne diseases and to establish a working group comprised of representatives of federal agencies, physicians and researchers, as well as patients, their family members and organizations that advocate on patients’ behalf.
Beyond Lyme: New Tick-Borne Diseases On The Rise In U.S., NPR, March 11, 2017In the Midwest, you can find Heartland virus, a new Lyme-like disease and Bourbon virus — which is thought to be spread by ticks but hasn’t been proven yet. In the South, there’s Southern tick-associated rash illness. Out west, there’s a new type of spotted fever. And across a big swath of the country, there’s a disease called ehrlichiosis.
WILDLIFE DISEASES AND HUMANS, Internet Center for Wildlife Damage Management. Diseases of wildlife can cause significant illness and death to individual animals and can significantly affect wildlife populations. Wildlife species can also serve as natural hosts for certain diseases that affect humans (zoonoses). The disease agents or parasites that cause these zoonotic diseases can be contracted from wildlife directly by bites or contamination, or indirectly through the bite of arthropod vectors such as mosquitoes, ticks, fleas, and mites that have previously fed on an infected animal. Humans have usually acquired diseases like Colorado tick fever, Rocky Mountain spotted fever, and Lyme disease because they have spent time in optimal habitats of disease vectors and hosts.