Ticks: Blood-sucking acarid parasites of the order Ixodida comprising two families: the softbacked ticks (ARGASIDAE) and hardbacked ticks (IXODIDAE). Ticks are larger than their relatives, the MITES. They penetrate the skin of their host by means of highly specialized, hooked mouth parts and feed on its blood. Ticks attack all groups of terrestrial vertebrates. In humans they are responsible for many TICK-BORNE DISEASES, including the transmission of ROCKY MOUNTAIN SPOTTED FEVER; TULAREMIA; BABESIOSIS; AFRICAN SWINE FEVER; and RELAPSING FEVER. (From Barnes, Invertebrate Zoology, 5th ed, pp543-44)Tick Infestations: Infestations with soft-bodied (Argasidae) or hard-bodied (Ixodidae) ticks.Ixodes: The largest genus of TICKS in the family IXODIDAE, containing over 200 species. Many infest humans and other mammals and several are vectors of diseases such as LYME DISEASE, tick-borne encephalitis (ENCEPHALITIS, TICK-BORNE), and KYASANUR FOREST DISEASE.Ixodidae: A family of hardbacked TICKS, in the subclass ACARI. Genera include DERMACENTOR and IXODES among others.Arachnid Vectors: Members of the class Arachnida, especially SPIDERS; SCORPIONS; MITES; and TICKS; which transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.Tick Control: Chemical, biological, or medical measures designed to prevent the spread of ticks or the concomitant infestations which result in tick-borne diseases. It includes the veterinary as well as the public health aspects of tick and mite control.Nymph: The immature stage in the life cycle of those orders of insects characterized by gradual metamorphosis, in which the young resemble the imago in general form of body, including compound eyes and external wings; also the 8-legged stage of mites and ticks that follows the first moult.Dermacentor: A widely distributed genus of TICKS, in the family IXODIDAE, including a number that infest humans and other mammals. Several are vectors of diseases such as TULAREMIA; ROCKY MOUNTAIN SPOTTED FEVER; COLORADO TICK FEVER; and ANAPLASMOSIS.Rhipicephalus: A genus of TICKS, in the family IXODIDAE, widespread in Africa. Members of the genus include many important vectors of animal and human pathogens.Tick-Borne Diseases: Bacterial, viral, or parasitic diseases transmitted to humans and animals by the bite of infected ticks. The families Ixodidae and Argasidae contain many bloodsucking species that are important pests of man and domestic birds and mammals and probably exceed all other arthropods in the number and variety of disease agents they transmit. Many of the tick-borne diseases are zoonotic.Tick Paralysis: Paralysis caused by a neurotropic toxin secreted by the salivary glands of ticks.Rickettsia: A genus of gram-negative, aerobic, rod-shaped bacteria often surrounded by a protein microcapsular layer and slime layer. The natural cycle of its organisms generally involves a vertebrate and an invertebrate host. Species of the genus are the etiological agents of human diseases, such as typhus.Lyme Disease: An infectious disease caused by a spirochete, BORRELIA BURGDORFERI, which is transmitted chiefly by Ixodes dammini (see IXODES) and pacificus ticks in the United States and Ixodes ricinis (see IXODES) in Europe. It is a disease with early and late cutaneous manifestations plus involvement of the nervous system, heart, eye, and joints in variable combinations. The disease was formerly known as Lyme arthritis and first discovered at Old Lyme, Connecticut.Rhipicephalus sanguineus: A species of tick (TICKS) in the family IXODIDAE, distributed throughout the world but abundant in southern Europe. It will feed on a wide variety of MAMMALS, but DOGS are its preferred host. It transmits a large number of diseases including BABESIOSIS; THEILERIASIS; EHRLICHIOSIS; and MEDITERRANEAN SPOTTED FEVER.Ornithodoros: A genus of softbacked TICKS, in the family ARGASIDAE, serving as the vector of BORRELIA, causing RELAPSING FEVER, and of the AFRICAN SWINE FEVER VIRUS.Borrelia: A genus of gram-negative, anaerobic, helical bacteria, various species of which produce RELAPSING FEVER in humans and other animals.Anaplasma phagocytophilum: A species of gram-negative bacteria in the genus ANAPLASMA, family ANAPLASMATACEAE, formerly called Ehrlichia phagocytophila or Ehrlichia equi. This organism is tick-borne (IXODES) and causes disease in horses and sheep. In humans, it causes human granulocytic EHRLICHIOSIS.Tick Bites: The effects, both local and systemic, caused by the bites of TICKS.Borrelia burgdorferi: A specific species of bacteria, part of the BORRELIA BURGDORFERI GROUP, whose common name is Lyme disease spirochete.Borrelia burgdorferi Group: Gram-negative helical bacteria, in the genus BORRELIA, that are the etiologic agents of LYME DISEASE. The group comprises many specific species including Borrelia afzelii, Borellia garinii, and BORRELIA BURGDORFERI proper. These spirochetes are generally transmitted by several species of ixodid ticks.Argasidae: A family of softbacked TICKS, in the subclass ACARI. Genera include ARGAS and ORNITHODOROS among others.Encephalitis, Tick-Borne: Encephalitis caused by neurotropic viruses that are transmitted via the bite of TICKS. In Europe, the diseases are caused by ENCEPHALITIS VIRUSES, TICK-BORNE, which give rise to Russian spring-summer encephalitis, central European encephalitis, louping ill encephalitis, and related disorders. Powassan encephalitis occurs in North America and Russia and is caused by the Powassan virus. ASEPTIC MENINGITIS and rarely encephalitis may complicate COLORADO TICK FEVER which is endemic to mountainous regions of the western United States. (From Joynt, Clinical Neurology, 1996, Ch26, pp14-5)Bites and StingsAcaricides: A pesticide or chemical agent that kills mites and ticks. This is a large class that includes carbamates, formamides, organochlorines, organophosphates, etc, that act as antibiotics or growth regulators.Ehrlichiosis: A tick-borne disease characterized by FEVER; HEADACHE; myalgias; ANOREXIA; and occasionally RASH. It is caused by several bacterial species and can produce disease in DOGS; CATTLE; SHEEP; GOATS; HORSES; and humans. The primary species causing human disease are EHRLICHIA CHAFFEENSIS; ANAPLASMA PHAGOCYTOPHILUM; and Ehrlichia ewingii.Rickettsia Infections: Infections by the genus RICKETTSIA.Encephalitis Viruses, Tick-Borne: A subgroup of the genus FLAVIVIRUS that causes encephalitis and hemorrhagic fevers and is found in eastern and western Europe and the former Soviet Union. It is transmitted by TICKS and there is an associated milk-borne transmission from viremic cattle, goats, and sheep.Colorado tick fever virus: A species of COLTIVIRUS transmitted by the tick DERMACENTOR andersonii and causing fever, chills, aching head and limbs, and often vomiting. It occurs in the northwestern United States, except the Pacific Coast.Ehrlichia: Small, often pleomorphic, coccoid to ellipsoidal organisms occurring intracytoplasmically in circulating LYMPHOCYTES. They are the etiologic agents of tick-borne diseases of humans; DOGS; CATTLE; SHEEP; GOATS; and HORSES.Salivary Glands: Glands that secrete SALIVA in the MOUTH. There are three pairs of salivary glands (PAROTID GLAND; SUBLINGUAL GLAND; SUBMANDIBULAR GLAND).Babesia: A genus of tick-borne protozoan parasites that infests the red blood cells of mammals, including humans. There are many recognized species, and the distribution is world-wide.Ectoparasitic Infestations: Infestations by PARASITES which live on, or burrow into, the surface of their host's EPIDERMIS. Most ectoparasites are ARTHROPODS.Arthropod Proteins: Proteins synthesized by organisms belonging to the phylum ARTHROPODA. Included in this heading are proteins from the subdivisions ARACHNIDA; CRUSTACEA; and HORSESHOE CRABS. Note that a separate heading for INSECT PROTEINS is listed under this heading.Colorado Tick Fever: A febrile illness characterized by chills, aches, vomiting, leukopenia, and sometimes encephalitis. It is caused by the COLORADO TICK FEVER VIRUS, a reovirus transmitted by the tick Dermacentor andersoni.Anaplasma: A genus of gram-negative bacteria whose organisms are obligate parasites of vertebrates. Species are transmitted by arthropod vectors with the host range limited to ruminants. Anaplasma marginale is the most pathogenic species and is the causative agent of severe bovine anaplasmosis.Borrelia Infections: Infections with bacteria of the genus BORRELIA.Tick Toxicoses: Toxicoses caused by toxic substances secreted by the salivary glands of ticks; include tick paralysis (neurotropic toxin), sweating sickness (dermotropic toxin), and Rhipicephalus appendiculatus toxicosis (leukotropic toxin).Anaplasmataceae: A family of bacteria which inhabit RED BLOOD CELLS and cause several animal diseases.Argas: A genus of softbacked TICKS in the family ARGASIDAE. Most infect birds or bats but a few parasitize terrestrial mammals.Disease Reservoirs: Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (DISEASE VECTORS) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks.Salivary Proteins and Peptides: Proteins and peptides found in SALIVA and the SALIVARY GLANDS. Some salivary proteins such as ALPHA-AMYLASES are enzymes, but their composition varies in different individuals.Anaplasmosis: A disease of cattle caused by parasitization of the red blood cells by bacteria of the genus ANAPLASMA.Babesiosis: A group of tick-borne diseases of mammals including ZOONOSES in humans. They are caused by protozoa of the genus BABESIA, which parasitize erythrocytes, producing hemolysis. In the U.S., the organism's natural host is mice and transmission is by the deer tick IXODES SCAPULARIS.Deer: The family Cervidae of 17 genera and 45 species occurring nearly throughout North America, South America, and Eurasia, on most associated continental islands, and in northern Africa. Wild populations of deer have been established through introduction by people in Cuba, New Guinea, Australia, New Zealand, and other places where the family does not naturally occur. They are slim, long-legged and best characterized by the presence of antlers. Their habitat is forests, swamps, brush country, deserts, and arctic tundra. They are usually good swimmers; some migrate seasonally. (Walker's Mammals of the World, 5th ed, p1362)Babesia microti: A species of protozoa infecting humans via the intermediate tick vector IXODES scapularis. The other hosts are the mouse PEROMYSCUS leucopus and meadow vole MICROTUS pennsylvanicus, which are fed on by the tick. Other primates can be experimentally infected with Babesia microti.Peromyscus: A genus of the subfamily SIGMODONTINAE consisting of 49 species. Two of these are widely used in medical research. They are P. leucopus, or the white-footed mouse, and P. maniculatus, or the deer mouse.Rocky Mountain Spotted Fever: An acute febrile illness caused by RICKETTSIA RICKETTSII. It is transmitted to humans by bites of infected ticks and occurs only in North and South America. Characteristics include a sudden onset with headache and chills and fever lasting about two to three weeks. A cutaneous rash commonly appears on the extremities and trunk about the fourth day of illness.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Ehrlichia chaffeensis: A species of gram-negative bacteria that is the causative agent of human EHRLICHIOSIS. This organism was first discovered at Fort Chaffee, Arkansas, when blood samples from suspected human ehrlichiosis patients were studied.Relapsing Fever: An acute infection characterized by recurrent episodes of PYREXIA alternating with asymptomatic intervals of apparent recovery. This condition is caused by SPIROCHETES of the genus BORRELIA. It is transmitted by the BITES of either the body louse (PEDICULUS humanus corporis), for which humans are the reservoir, or by soft ticks of the genus ORNITHODOROS, for which rodents and other animals are the principal reservoirs.Rodentia: A mammalian order which consists of 29 families and many genera.Insect Bites and Stings: Bites and stings inflicted by insects.Anaplasma marginale: A species of gram-negative bacteria and causative agent of severe bovine ANAPLASMOSIS. It is the most pathogenic of the ANAPLASMA species.Spirochaetales: An order of slender, flexuous, helically coiled bacteria, with one or more complete turns in the helix.Bacterial Outer Membrane Proteins: Proteins isolated from the outer membrane of Gram-negative bacteria.PolandPhylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.Larva: Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.Rodent Diseases: Diseases of rodents of the order RODENTIA. This term includes diseases of Sciuridae (squirrels), Geomyidae (gophers), Heteromyidae (pouched mice), Castoridae (beavers), Cricetidae (rats and mice), Muridae (Old World rats and mice), Erethizontidae (porcupines), and Caviidae (guinea pigs).Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Cattle Diseases: Diseases of domestic cattle of the genus Bos. It includes diseases of cows, yaks, and zebus.Rickettsia rickettsii: A species of gram-negative, aerobic bacteria that is the etiologic agent of ROCKY MOUNTAIN SPOTTED FEVER. Its cells are slightly smaller and more uniform in size than those of RICKETTSIA PROWAZEKII.Disease Vectors: Invertebrates or non-human vertebrates which transmit infective organisms from one host to another.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Anaplasmataceae Infections: Infections with bacteria of the family ANAPLASMATACEAE.Hemorrhagic Fever, Crimean: A severe, often fatal disease in humans caused by the Crimean-Congo hemorrhagic fever virus (HEMORRHAGIC FEVER VIRUS, CRIMEAN-CONGO).Hemorrhagic Fever Virus, Crimean-Congo: A species of NAIROVIRUS of the family BUNYAVIRIDAE. It is primarily transmitted by ticks and causes a severe, often fatal disease in humans.