Tick
Overview
Ticks are small arachnid
Arachnid
Arachnids are a class of joint-legged invertebrate animals in the subphylum Chelicerata. All arachnids have eight legs, although in some species the front pair may convert to a sensory function. The term is derived from the Greek words , meaning "spider".Almost all extant arachnids are terrestrial...

s in the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Ixodida, along with mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...

s, constitute the subclass Acarina
Acarina
Acari are a taxon of arachnids that contains mites and ticks. The diversity of the Acari is extraordinary and its fossil history goes back to at least the early Devonian period. As a result, acarologists have proposed a complex set of taxonomic ranks to classify mites...

. Ticks are ectoparasites (external parasites), living by hematophagy
Hematophagy
Hematophagy is the practice of certain animals of feeding on blood...

 on the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 of mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s, bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s, and sometimes reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

s and amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...

s. Ticks are vectors of a number of diseases, including Lyme disease
Lyme disease
Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...

, Q fever
Q fever
Q fever is a disease caused by infection with Coxiella burnetii, a bacterium that affects humans and other animals. This organism is uncommon but may be found in cattle, sheep, goats and other domestic mammals, including cats and dogs...

 (rare; more commonly transmitted by infected excreta), Colorado tick fever
Colorado tick fever
Colorado Tick Fever is an obtuse viral infection transmitted from the bite of an infected tick...

, Rocky Mountain Spotted Fever
Rocky Mountain spotted fever
Rocky Mountain spotted fever is the most lethal and most frequently reported rickettsial illness in the United States. It has been diagnosed throughout the Americas. Some synonyms for Rocky Mountain spotted fever in other countries include “tick typhus,” “Tobia fever” , “São Paulo fever” or “febre...

, tularemia
Tularemia
Tularemia is a serious infectious disease caused by the bacterium Francisella tularensis. A Gram-negative, nonmotile coccobacillus, the bacterium has several subspecies with varying degrees of virulence. The most important of those is F...

, tick-borne relapsing fever
Relapsing fever
Relapsing fever is an infection caused by certain bacteria in the genus Borrelia. It is a vector-borne disease that is transmitted through the bites of lice or soft-bodied ticks.-Louse-borne relapsing fever:...

, babesiosis
Babesiosis
Babesiosis is a malaria-like parasitic disease caused by infection with Babesia, a genus of protozoal piroplasms. After trypanosomes, Babesia are thought to be the second most common blood parasites of mammals and they can have a major impact on health of domestic animals in areas without severe...

, ehrlichiosis
Ehrlichiosis
Ehrlichiosis is a tick-borne disease of dogs usually caused by the organism Ehrlichia canis. Ehrlichia canis is the pathogen of animals. Humans can become infected by E. canis and other species after tick exposure. German Shepherd dogs are thought to be particularly affected by the disease, other...

, Tick paralysis
Tick paralysis
Tick paralysis is the only tick-borne disease that is not caused by an infectious organism. The illness is caused by a neurotoxin produced in the tick's salivary gland. After prolonged attachment, the engorged tick transmits the toxin to its host...

 and tick-borne meningoencephalitis
Tick-borne meningoencephalitis
Tick-borne encephalitis is a viral infectious disease involving the central nervous system. The disease most often manifests as meningitis, encephalitis, or meningoencephalitis. Although TBE is most commonly recognized as a neurological disorder, mild fever can also occur...

, as well as bovine anaplasmosis
Anaplasmosis
Anaplasmosis is a disease caused by a rickettsial parasite of ruminants, Anaplasma spp. The organism occurs in the white blood cells and is transmitted by natural means through a number of haematophagous species of ticks...

.
There are three families
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of ticks, one of which – Nuttalliellidae
Nuttalliellidae
Nuttalliella namaqua is a tick found in southern Africa from Tanzania to Namibia and South Africa, which is placed in its own family, Nuttalliellidae. It can be distinguished from ixodid ticks and argasid ticks by a combination of characters including the position of the stigmata, lack of setae,...

 – comprises a single species, Nuttalliella namaqua.
Encyclopedia
Ticks are small arachnid
Arachnid
Arachnids are a class of joint-legged invertebrate animals in the subphylum Chelicerata. All arachnids have eight legs, although in some species the front pair may convert to a sensory function. The term is derived from the Greek words , meaning "spider".Almost all extant arachnids are terrestrial...

s in the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Ixodida, along with mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...

s, constitute the subclass Acarina
Acarina
Acari are a taxon of arachnids that contains mites and ticks. The diversity of the Acari is extraordinary and its fossil history goes back to at least the early Devonian period. As a result, acarologists have proposed a complex set of taxonomic ranks to classify mites...

. Ticks are ectoparasites (external parasites), living by hematophagy
Hematophagy
Hematophagy is the practice of certain animals of feeding on blood...

 on the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 of mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s, bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s, and sometimes reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

s and amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...

s. Ticks are vectors of a number of diseases, including Lyme disease
Lyme disease
Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...

, Q fever
Q fever
Q fever is a disease caused by infection with Coxiella burnetii, a bacterium that affects humans and other animals. This organism is uncommon but may be found in cattle, sheep, goats and other domestic mammals, including cats and dogs...

 (rare; more commonly transmitted by infected excreta), Colorado tick fever
Colorado tick fever
Colorado Tick Fever is an obtuse viral infection transmitted from the bite of an infected tick...

, Rocky Mountain Spotted Fever
Rocky Mountain spotted fever
Rocky Mountain spotted fever is the most lethal and most frequently reported rickettsial illness in the United States. It has been diagnosed throughout the Americas. Some synonyms for Rocky Mountain spotted fever in other countries include “tick typhus,” “Tobia fever” , “São Paulo fever” or “febre...

, tularemia
Tularemia
Tularemia is a serious infectious disease caused by the bacterium Francisella tularensis. A Gram-negative, nonmotile coccobacillus, the bacterium has several subspecies with varying degrees of virulence. The most important of those is F...

, tick-borne relapsing fever
Relapsing fever
Relapsing fever is an infection caused by certain bacteria in the genus Borrelia. It is a vector-borne disease that is transmitted through the bites of lice or soft-bodied ticks.-Louse-borne relapsing fever:...

, babesiosis
Babesiosis
Babesiosis is a malaria-like parasitic disease caused by infection with Babesia, a genus of protozoal piroplasms. After trypanosomes, Babesia are thought to be the second most common blood parasites of mammals and they can have a major impact on health of domestic animals in areas without severe...

, ehrlichiosis
Ehrlichiosis
Ehrlichiosis is a tick-borne disease of dogs usually caused by the organism Ehrlichia canis. Ehrlichia canis is the pathogen of animals. Humans can become infected by E. canis and other species after tick exposure. German Shepherd dogs are thought to be particularly affected by the disease, other...

, Tick paralysis
Tick paralysis
Tick paralysis is the only tick-borne disease that is not caused by an infectious organism. The illness is caused by a neurotoxin produced in the tick's salivary gland. After prolonged attachment, the engorged tick transmits the toxin to its host...

 and tick-borne meningoencephalitis
Tick-borne meningoencephalitis
Tick-borne encephalitis is a viral infectious disease involving the central nervous system. The disease most often manifests as meningitis, encephalitis, or meningoencephalitis. Although TBE is most commonly recognized as a neurological disorder, mild fever can also occur...

, as well as bovine anaplasmosis
Anaplasmosis
Anaplasmosis is a disease caused by a rickettsial parasite of ruminants, Anaplasma spp. The organism occurs in the white blood cells and is transmitted by natural means through a number of haematophagous species of ticks...

.

Taxonomy

There are three families
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of ticks, one of which – Nuttalliellidae
Nuttalliellidae
Nuttalliella namaqua is a tick found in southern Africa from Tanzania to Namibia and South Africa, which is placed in its own family, Nuttalliellidae. It can be distinguished from ixodid ticks and argasid ticks by a combination of characters including the position of the stigmata, lack of setae,...

 – comprises a single species, Nuttalliella namaqua. The remaining two families contain the hard ticks (Ixodidae
Ixodidae
Ixodidae is a family of ticks containing the hard ticks.-Description:They are distinguished from the other main family of ticks, the soft ticks by the presence of a scutum or hard shield...

) and the soft ticks (Argasidae
Argasidae
Argasidae is a family of ticks containing the soft ticks. They lack the hard scutum that is present in the hard ticks . The capitulum is located on the underside of the animal's body and is not readily visible...

).

Ixodidae are distinguished from the Argasidae by the presence of a scutum or hard shield. Ixodidae nymphs and adults both have a prominent capitulum (head) which projects forwards from the body; in the Argasidae, conversely, the capitulum is concealed beneath the body.

Argasidae contains 193 species, although the composition of the genera is less certain, and more study is needed before the genera can become stable. The currently accepted genera are Antricola
Antricola
Antricola is a genus of tick. It contains 16 species-Species:*Antricola delacruzi Estrada-Pena, Barros-Battesti & Venzal, 2004*Antricola guglielmonei Estrada-Pena, Barros-Battesti & Venzal, 2004*Antricola inexpectata...

, Argas
Argas
Argas is a genus of tick.-Species:* Argas abdussalami Hoogstraal & McCarthy, 1965* Argas acinus Whittick, 1938* Argas africolumbae Hoogstraal, Kaiser, Walker, Ledger, Converse & Rice, 1975...

, Nothaspis, Ornithodoros
Ornithodoros
Ornithodoros is a genus in the soft-bodied tick family, Argasidae. The Linnean name derives from ornithos and doros , meaning "bird" and "gift," respectively...

and Otobius. Though common in North America, they feed rapidly, primarily on birds, and are very rarely found to parasitize land animals or humans.

Nuttalliella namaqua is a tick found in southern Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 from Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

 to Namibia
Namibia
Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...

 and South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, which is placed in its own family, Nuttalliellidae. It can be distinguished from ixodid ticks
Ixodidae
Ixodidae is a family of ticks containing the hard ticks.-Description:They are distinguished from the other main family of ticks, the soft ticks by the presence of a scutum or hard shield...

 and argasid ticks
Argasidae
Argasidae is a family of ticks containing the soft ticks. They lack the hard scutum that is present in the hard ticks . The capitulum is located on the underside of the animal's body and is not readily visible...

 by a combination of characters including the position of the stigmata, lack of setae, strongly corrugated integument, and form of the fenestrated plates.

Fossilized ticks are common. Recent hypotheses based on total-evidence approach analysis place the origin of ticks in the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

  with most of the evolution and dispersal occurring during the Tertiary
Tertiary
The Tertiary is a deprecated term for a geologic period 65 million to 2.6 million years ago. The Tertiary covered the time span between the superseded Secondary period and the Quaternary...

 . The oldest example is an argasid (bird) tick from Cretaceous New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...

 amber
Amber
Amber is fossilized tree resin , which has been appreciated for its color and natural beauty since Neolithic times. Amber is used as an ingredient in perfumes, as a healing agent in folk medicine, and as jewelry. There are five classes of amber, defined on the basis of their chemical constituents...

. The younger Baltic
Baltic amber
The Baltic region is home to the largest known deposit of amber, called Baltic amber or succinite, with about 80% of the world's known amber found there. It dates from 44 million years ago...

 and Dominican amber
Dominican amber
Dominican amber is amber from the Dominican Republic. Resin from the extinct species Hymenaea protera is the source of Dominican amber and probably of most amber found in the tropics....

s have also yielded examples, all of which can be placed in living genera.

Range and habitat

Tick species are widely distributed around the world. However, they tend to flourish more in countries with warm, humid climates, because they require a certain amount of moisture in the air in order to undergo metamorphosis, and because low temperatures inhibit their development from egg to larva.

For an ecosystem to support ticks, it must satisfy two requirements: there must be a high enough population density of host species in the area, and there must be high enough humidity for ticks to remain hydrated. Due to their role in transmitting Lyme disease, ixodid ticks, particularly I. scapularis, have been studied using geographic information systems (GIS
Geographic Information System
A geographic information system, geographical information science, or geospatial information studies is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographically referenced data...

), in order to develop predictive models for ideal tick habitats. According to these studies, it was determined that certain features of a given micro-climate – such as sandy soil, hardwood trees, rivers, and the presence of deer – are good predictors of dense tick populations.

Anatomy and physiology

Ticks, like mites, have bodies which are divided into two primary sections: the anterior capitulum (or gnathosoma), which contains the head and mouthparts; and the posterior idiosoma which contains the legs, digestive tract, and reproductive organs.

Diet and feeding behaviors

Ticks satisfy all of their nutritional requirements on a diet of blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

, a practice known as hematophagy
Hematophagy
Hematophagy is the practice of certain animals of feeding on blood...

. They extract the blood by cutting a hole in the host's epidermis
Epidermis (zoology)
The Epidermis is an epithelium that covers the body of an eumetazoan . Eumetazoa have a cavity lined with a similar epithelium, the gastrodermis, which forms a boundary with the epidermis at the mouth.Sponges have no epithelium, and therefore no epidermis or gastrodermis...

, into which they insert their hypostome
Hypostome
A hypostome , is a calcified harpoon-like structure near the mouth area of certain parasitic arthropods including ticks and mites , that allows them to anchor themselves firmly in place on a host mammal while sucking blood...

, likely keeping the blood from clotting by excreting an anticoagulant
Anticoagulant
An anticoagulant is a substance that prevents coagulation of blood. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders. Some anticoagulants are used in medical equipment, such as test tubes, blood transfusion bags, and renal dialysis...

.

Legs

The legs of Ixodidae and Argasidae are similar in structure. Each leg is composed of six segments: the coxa, trochanter, femur, patella, tibia, and tarsus. Each of these segments are connected by muscles which allow for flexion
Flexion
In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...

 and extension
Extension (kinesiology)
In kinesiology, extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of...

, however the coxae have limited lateral movement. When not being used for walking, the legs remain tightly folded against the body.

In addition to being used for locomotion
Locomotion
The term locomotion means movement or travel. It may refer to:* Motion * Animal locomotion** Terrestrial locomotion* TravelLocomotion may refer to specific types of motion:* Gait analysis* walking* running, including trotting...

, the tarsus of leg I contains a unique sensory organ known as the Haller's organ
Haller's organ
Haller's organ is a complex sensory organ that ticks bear. The organ detects hosts – which the tick, being an obligate parasite, must find in order to survive – via olfaction and the sensing of humidity, temperature, and carbon dioxide. Haller's organ is a minute cavity at the terminal segment of...

 which can detect odors and chemicals emanating from the host, as well as sensing changes in temperature and air currents.

Ixodidae

Both ixodid and argasid ticks undergo three primary stages of development: larval, nymphal, and adult. Ixodid ticks require three hosts, and their life cycle takes at least one year to complete. Up to 3,000 eggs are laid on the ground by an adult female tick. When larvae emerge, they feed primarily on small mammals and birds. After feeding, they detach from their host and molt to nymphs on the ground, which then feed on larger hosts and molt to adults. Female adults attach to larger hosts, feed, and lay eggs, while males feed very little and occupy larger hosts primarily for mating.

Argasidae

Argasid ticks, unlike ixodid ticks, may go through several nymphal stages, requiring a meal of blood each time. Their lifecycle ranges from months to years. The adult female argasid tick can lay anywhere from a few hundred to over a thousand eggs over the course of her lifetime. Larvae feed very quickly and detach to molt to nymphs. Nymphs may go through as many as seven instars
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...

, each requiring a blood meal. Both male and female adults blood-feed, and they mate off the host. During feeding, any excess fluid is excreted by the coxal glands, a process which is unique to argasid ticks.

Medical issues

Tick-borne disease

Tick-borne illnesses are caused by infection with a variety of pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...

s, including rickettsia
Rickettsia
Rickettsia is a genus of non-motile, Gram-negative, non-sporeforming, highly pleomorphic bacteria that can present as cocci , rods or thread-like . Being obligate intracellular parasites, the Rickettsia survival depends on entry, growth, and replication within the cytoplasm of eukaryotic host cells...

 and other types of bacteria, virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...

es, and protozoa
Protozoa
Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...

. Because ticks can harbor more than one disease-causing agent, patients can be infected with more than one pathogen at the same time, compounding the difficulty in diagnosis and treatment. Major tick-borne diseases include Lyme disease
Lyme disease
Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...

, Rocky Mountain spotted fever
Rocky Mountain spotted fever
Rocky Mountain spotted fever is the most lethal and most frequently reported rickettsial illness in the United States. It has been diagnosed throughout the Americas. Some synonyms for Rocky Mountain spotted fever in other countries include “tick typhus,” “Tobia fever” , “São Paulo fever” or “febre...

, relapsing fever
Relapsing fever
Relapsing fever is an infection caused by certain bacteria in the genus Borrelia. It is a vector-borne disease that is transmitted through the bites of lice or soft-bodied ticks.-Louse-borne relapsing fever:...

, tularemia
Tularemia
Tularemia is a serious infectious disease caused by the bacterium Francisella tularensis. A Gram-negative, nonmotile coccobacillus, the bacterium has several subspecies with varying degrees of virulence. The most important of those is F...

, tick-borne meningoencephalitis
Tick-borne meningoencephalitis
Tick-borne encephalitis is a viral infectious disease involving the central nervous system. The disease most often manifests as meningitis, encephalitis, or meningoencephalitis. Although TBE is most commonly recognized as a neurological disorder, mild fever can also occur...

, Colorado tick fever
Colorado tick fever
Colorado Tick Fever is an obtuse viral infection transmitted from the bite of an infected tick...

, Crimean-Congo hemorrhagic fever
Crimean-Congo hemorrhagic fever
Crimean–Congo hemorrhagic fever is a widespread tick-borne viral disease, a zoonosis of domestic animals and wild animals, that may affect humans. The pathogenic virus, especially common in East and West Africa, is a member of the Bunyaviridae family of RNA viruses. Clinical disease is rare in...

, babesiosis
Babesiosis
Babesiosis is a malaria-like parasitic disease caused by infection with Babesia, a genus of protozoal piroplasms. After trypanosomes, Babesia are thought to be the second most common blood parasites of mammals and they can have a major impact on health of domestic animals in areas without severe...

 and cytauxzoonosis
Cytauxzoonosis
Cytauxzoonosis is a mostly fatal tick-borne disease of domestic cats. It is identified as the blood parasite Cytauxzoon felis.In Africa, this disease is carried by ungulates, but in North America, it is carried by bobcats, particularly in the South...

. A new find is a bacteria that causes blood clots is candidatus neoehrlichia mikurensis. It mainly affects persons with lowered immune defense and is present in 9% of rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s, and can be cured with antibiotics.

Tick bites may induce an allergy to red meat
Red meat
Red meat in traditional culinary terminology is meat which is red when raw and not white when cooked. In the nutritional sciences, red meat includes all mammal meat. Red meat includes the meat of most adult mammals and some fowl ....

 in some people, due to the allergen
Allergen
An allergen is any substance that can cause an allergy. In technical terms, an allergen is a non-parasitic antigen capable of stimulating a type-I hypersensitivity reaction in atopic individuals....

 galactose alpha-1,3-galactose. Allergic reactions to red meat typically occur in individuals who have had local allergic reactions to ticks. Within six months or so they develop anaphylaxis
Anaphylaxis
Anaphylaxis is defined as "a serious allergic reaction that is rapid in onset and may cause death". It typically results in a number of symptoms including throat swelling, an itchy rash, and low blood pressure...

 to red meat which almost invariably occurs several hours after eating red meat. The reactions may rarely be profound, due to the co-existence of an increased number of mast cell
Mast cell
A mast cell is a resident cell of several types of tissues and contains many granules rich in histamine and heparin...

s (mastocytosis
Mastocytosis
Mastocytosis is a group of rare disorders of both children and adults caused by the presence of too many mast cells and CD34+ mast cell precursors in a person's body.- Classification :Mastocytosis can occur in a variety of forms:...

).

Eggs can be infected with pathogens inside of the ovaries
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...

, meaning that baby ticks can be infectious immediately at birth, before feeding on their first host.

First aid

In general, the best way to remove adult Ixodidae is mechanically. If the tick's head and mouthparts are not attached to the body after removal, it may be necessary to perform a punch biopsy to remove any parts remaining inside the patient.

Population control measures

With the possible exception of widespread DDT
DDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....

 use in the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

, attempts to limit the population or distribution of disease-causing ticks have been very unsuccessful.

The parasitic Ichneumon wasp
Ichneumon wasp
The Ichneumonoidea are insects classified in the hymenopteran suborder Apocrita. The superfamily is made up of the ichneumon wasps and the braconids...

 Ixodiphagus hookeri
Ixodiphagus hookeri
The Chalcid wasp Ixodiphagus hookeri lays its eggs into ticks. It seems to utilize a symbiotic virus to weaken the tick's immune system.Ticks from the following genera are infected:*Amblyomma*Dermacentor*Haemaphysalis*Hyalomma...

has long been investigated for its potential to control tick populations. It lays its eggs into ticks; the hatching wasps kill their host.

Another natural form of control for ticks is the guineafowl
Guineafowl
The guineafowl are a family of birds in the Galliformes order, although some authorities include the guineafowl as a subfamily, Numidinae, of the family Phasianidae...

, a bird species which consumes mass quantities of ticks. Just 2 birds can clear 2 acres (8,093.7 m²) in a single year.

Topical (drops/dust) flea/tick medicines may be toxic to animals and humans. Phenothrin
Phenothrin
Phenothrin, also called sumithrin, is a synthetic pyrethroid that kills adult fleas and ticks. It has also been used to kill head lice in humans...

 (85.7%) in combination with Methoprene
Methoprene
Methoprene is a juvenile hormone analog which can be used as an insecticide that acts as a growth regulator. Methoprene is an amber-colored liquid with a faint fruity odor which is essentially nontoxic to humans when ingested or inhaled. It is used in drinking water cisterns to control mosquitoes...

 was a popular topical flea/tick therapy for felines. Phenothrin kills adult fleas and ticks. Methoprene
Methoprene
Methoprene is a juvenile hormone analog which can be used as an insecticide that acts as a growth regulator. Methoprene is an amber-colored liquid with a faint fruity odor which is essentially nontoxic to humans when ingested or inhaled. It is used in drinking water cisterns to control mosquitoes...

 is an insect growth regulator that interrupts the insect's life cycle by killing the eggs. However, the U.S. Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...

 required at least one manufacturer of these products to withdraw some products and include strong cautionary statements on others, warning of adverse reactions.

Deer ticks

The black legged or deer tick (Ixodes scapularis
Ixodes scapularis
Ixodes scapularis is commonly known as the deer tick or blacklegged tick , and in some parts of the USA as the bear tick. It is a hard-bodied tick of the eastern and northern Midwestern United States...

) is dependent on the white-tailed deer
White-tailed Deer
The white-tailed deer , also known as the Virginia deer or simply as the whitetail, is a medium-sized deer native to the United States , Canada, Mexico, Central America, and South America as far south as Peru...

 for reproduction. Larval and nymph stages (immature ticks that cannot reproduce) of the deer tick feed on birds and small mammals. The adult female tick needs a large 3-day blood meal from the deer before she can reproduce and lay her 2000 or more eggs. Deer are the primary host for the adult deer tick and are key to the reproductive success of the tick.

Numerous studies have shown that abundance and distribution of deer ticks are correlated with reduced deer densities.

When the deer population was reduced by 74% at a 248 acres (100.4 ha) study site in Bridgeport, Connecticut
Bridgeport, Connecticut
Bridgeport is the most populous city in the U.S. state of Connecticut. Located in Fairfield County, the city had an estimated population of 144,229 at the 2010 United States Census and is the core of the Greater Bridgeport area...

, for example, the number of nymphal ticks collected at the site decreased by 92%. The relationship between deer abundance, tick abundance, and human cases of Lyme disease
Lyme disease
Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...

 was well documented in the Mumford Cove Community in Groton, Connecticut
Groton, Connecticut
Groton is a town located on the Thames River in New London County, Connecticut, United States. The population was 39,907 at the 2000 census....

, from 1996 to 2004. The deer population in Mumford Cove was reduced from about 77 deer per square mile to about 10 deer per square mile (4 deer per square kilometer) after 2 years of controlled hunting. After the initial reduction the deer population was maintained at low levels. Reducing deer densities to 10 deer per square mile (4 deer per square kilometer) was adequate to reduce by more than 90% the risk of humans contracting Lyme disease in Mumford Cove.

A 2006 study by Penn State's Center for Infectious Disease Dynamics indicated that reducing the deer population in small areas may lead to higher tick densities, resulting in more tick-borne infections in rodents leading to a high prevalence of tick-borne encephalitis
Encephalitis
Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue...

 and creating a tick hot-spot.

See also

  • Flea
    Flea
    Flea is the common name for insects of the order Siphonaptera which are wingless insects with mouthparts adapted for piercing skin and sucking blood...

  • Mosquito
    Mosquito
    Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...

  • Parasitology
    Parasitology
    Parasitology is the study of parasites, their hosts, and the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question, but by their way of life...

  • Vampire bat
    Vampire bat
    Vampire bats are bats whose food source is blood, a dietary trait called hematophagy. There are three bat species that feed solely on blood: the Common Vampire Bat , the Hairy-legged Vampire Bat , and the White-winged Vampire Bat .All three species are native to the Americas, ranging from Mexico to...

  • Rickettsia helvetica
    Rickettsia helvetica
    Rickettsia helvetica is a bacterium found in Dermacentor reticulatus and other ticks that was previously thought harmless. In 1997, a man living in eastern France had seroconverted to Rickettsia 4 weeks after the onset of a then unexplained febrile illness...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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