Rhipicephalus microplus | |
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Species: | R. microplus |
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Rhipicephalus microplus (Canestrini, 1888) | |
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The Asian blue tick (Rhipicephalus (Boophilus) microplus, Rhipicephalus microplus, or Boophilus microplus) is an economically important tick that parasitises a variety of livestock and wild mammal species, [1] especially cattle, on which it is the most economically significant ectoparasite in the world. [2] It is known as the Australian cattle tick, southern cattle tick, Cuban tick, Madagascar blue tick, and Puerto Rican Texas fever tick. [3]
It is classified as a hard tick in the family Ixodidae. It is a small teardrop-shaped arachnid with a hardened plate called the scutum covering its head. Males are entirely covered in scutum on their backs with additional plates called festoons along their sides. The body can be brown or pale in nymphs and darkens as the tick matures. Adults have 8 cream-colored legs. [1]
In R. microplus the hypostome has a hexagonal base (basis capitulum) which can be used as an identifying characteristic. Ticks may be identified by the arrangement of hair-like structures called setae. In R. microplus the setae are arranged in rows of two or three along the tick's body behind the scutum. [1]
Rhipicephalus microplus is best known for being a cattle parasite. However, it has also been discovered in a number of other animal hosts such as domestic water buffalo, wild and domestic goats, horses, wild pigs, various rat species, and humans. [4]
R. microplus serves as a vector for numerous pathogens, most notably Babesia bigemina and B. bovis . B. bigemina and B. bovis are responsible for bovine babesiosis which is ranked as the most economically important arthropod-transmitted illness in cattle. Bovine babesiosis is characterized by anemia, fever, and potentially multiple organ failure. [5] This results in weight loss and lower milk production in infected cattle and therefore, massive economic losses in countries like Brazil where 80% of the cattle population is infected. [6] R. microplus has also been shown to be a vector for Ehrlichia ruminantium in West Africa. [7] E. ruminantium causes fluid buildup around the heart in cattle and other species, a condition with an 80% mortality rate, causing significant economic damage in infected areas. [7] [8]
Rhipicephalus microplus was originally found in the tropical and sub-tropical forests of India. However, due to the centuries-long movement of cattle around Europe, R. microplus has dramatically spread from its original range, making it to the United States between 4 and 5 centuries ago. [9] [10] R. microplus is generally found between 32°N and 32°S, a region strongly overlapping with major cattle breeding countries and territories. [9]
Nearly a cosmopolitan species, Asian blue tick is found specifically in Costa Rica, Anguilla, Antigua and Barbuda, Brazil, Bahamas, Barbados, Belize, Bolivia, Argentina, Colombia, Cote D'Ivoire, Cuba, Dominica, Ecuador, El Salvador, Ethiopia, French Guiana, Guadeloupe, Guam, Guatemala, Guyana, Honduras, India, Indonesia, Jamaica, Libya, Madagascar, Malawi, Martinique, Mexico, Montserrat, Mozambique, Nicaragua, Panama, Paraguay, Peru, Puerto Rico, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, South Africa, Sri Lanka, Suriname, Tanzania, Trinidad and Tobago, Uganda, Uruguay, Venezuela, Vietnam, Virgin Islands (U.S.), Zambia and Zimbabwe. [11]
Tick populations in Australia once thought to belong to R. microplus are now recognized to belong to R. australis, which was reinstated as a sibling species of R. microplus in 2012. [12]
Having formerly been present in the United States, it has since been eradicated there, except for sporadic occurrences in a buffer zone along the Mexican border. [1]
In Louisiana, Governor Ruffin Pleasant in 1917 signed legislation sponsored by freshman State Senator Norris C. Williamson of East Carroll Parish to authorize state funding to eradicate the cattle tick. [13]
Some veterinary science research suggests that R. microplus could become established in the currently temperate countries once their autumns and winters become warmer by about 2–2.75 °C (3.60–4.95 °F). [14]
The life cycle of R. microplus has been examined under laboratory conditions using rabbit hosts. The average life cycle was determined to be approximately 65 days. The life cycle begins with an adult female which feeds for approximately 7 days before entering a 4-day pre-oviposition period. During pre-oviposition a female will mate with any and all males who present themselves. The female tick then spends 8.6 days in oviposition, during which time she will lay her eggs. On average, each female lays about 1450 eggs per brood. The eggs take about 21 days to hatch. Approximately 83.5% will survive to hatch into a free-living larval stage which lasts for 3.5 days. The larvae have their first feeding at this time, and their first molt 8 days later. At this point, the larvae have become nymphs. They will feed for 11 days before becoming adults. [15]
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Management efforts in the United States began after R. microplus was deemed responsible for an estimated $63 billion in damages during the early 19th century. A control campaign began in 1906 and by 1943 it was considered complete, having eradicated most of the tick population other than a small region along the Southern US border. [9] [10] In the modern day, the standard form of control is spraying of acaricides: a type of pesticide that targets ticks and mites. Overuse of acaricides has resulted in some R. microplus populations developing resistance, [16] and it is now considered the most resistant tick ever. [4] Other control methods include ivermectin, a common anti-parasitic. In Mexico, it has been shown that R. microplus populations are developing varying levels of resistance to ivermectin, meaning this treatment is becoming less effective year over year. [17]
Vaccinating cattle against R. microplus was considered as another option, however, the original Bm86-based vaccines have shown limited efficacy against R. microplus as compared to other tick species. [4]
Acaricides and pyrethroids are commonly used however this has led to the development of acaricide- and pyrethroid- resistances. [2] Acaricide resistance in R. microplus is mediated by para sodium channel mutants. [2] Such alleles can be rapidly detected in a border livestock inspection by PCR+High Resolution Melt testing. [2] This is especially useful on the United States-Mexico border where the US has almost eradicated R. microplus, but Mexico has a high prevalence and a high prevalence of acaricide resistance. [2] This technique could also be applied in other countries where pyrethroid resistant R. microplus is a common problem. [2]
Some populations of R. microplus have developed resistance to acetylcholinesterase inhibitors. [18] The search for the acetylcholinesterase (AChE) mutations responsible has been stymied because, although there are only three AChEs in this genome, all three have a high copy number. [18] Progress has been made by Bellgard et al., 2012, Temeyer et al., 2012, and Bendele et al., 2015 toward identifying acaricide resistance alleles. [18]
Another management option that has shown promise is the use of pasture rotation. This is based on knowledge of the R. microplus life cycle. A large pasture is divided up into multiple regions that cattle are moved between regularly. The rotation time is based on the time it takes the R. microplus eggs to hatch. If timed correctly, the larvae in an area only become viable after the cattle have moved, leading to loss of that R. microplus generation. This has been shown to be effective in reducing the tick population. However, the amount of time a pasture needs to remain empty means it isn't generally economically viable for farmers. [16]
Ticks are parasitic arachnids of the order Ixodida. They are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by feeding on the blood of mammals, birds, and sometimes reptiles and amphibians. The timing of the origin of ticks is uncertain, though the oldest known tick fossils are from the Cretaceous period, around 100 million years old. Ticks are widely distributed around the world, especially in warm, humid climates.
Babesia, also called Nuttallia, is an apicomplexan parasite that infects red blood cells and is transmitted by ticks. Originally discovered by Romanian bacteriologist Victor Babeș in 1888; over 100 species of Babesia have since been identified.
Anaplasmosis is a tick-borne disease affecting ruminants, dogs, and horses, and is caused by Anaplasma bacteria. Anaplasmosis is an infectious but not contagious disease. Anaplasmosis can be transmitted through mechanical and biological vector processes. Anaplasmosis can also be referred to as "yellow bag" or "yellow fever" because the infected animal can develop a jaundiced look. Other signs of infection include weight loss, diarrhea, paleness of the skin, aggressive behavior, and high fever.
Heartwater is a tick-borne rickettsial disease. The name is derived from the fact that fluid can collect around the heart or in the lungs of infected animals. It is caused by Ehrlichia ruminantium —an intracellular Gram-negative coccal bacterium. The disease is spread by various Amblyomma ticks, and has a large economic impact on cattle production in affected areas. There are four documented manifestations of the disease, these are acute, peracute, subacute, and a mild form known as heartwater fever. There are reports of zoonotic infections of humans by E. ruminantium, similar to other Ehrlichia species, such as those that cause human ehrlichiosis.
Rhipicephalus sanguineus, commonly called the brown dog tick, kennel tick, or pantropical dog tick, is a species of tick found worldwide, but more commonly in warmer climates. This species is unusual among ticks in that its entire lifecycle can be completed indoors. The brown dog tick is easily recognized by its reddish-brown color, elongated body shape, and hexagonal basis capituli. Adults are 2.28 to 3.18 mm in length and 1.11 to 1.68 mm in width. They do not have ornamentation on their backs.
Dermacentor is a genus of ticks in the family Ixodidae, the hard ticks. The genus has a cosmopolitan distribution, with native species on all continents except Australia. Most are found in North America.
Rhipicephalus is a genus of ticks in the family Ixodidae, the hard ticks, consisting of about 74 or 75 species. Most are native to tropical Africa.
Ixodes pacificus, the western black-legged tick, is a species of tick found on the western coast of North America. I. pacificus is a member of the family Ixodidae. It is the principal vector of Lyme disease in that region. I. pacificus larvae and nymphs typically feeds on lizards and small mammals, while adults typically feed on deer. It is an ectoparasite that attaches itself to the outside of its host and feeds on the host's blood. It can have a heteroxenous lifestyle or monoxenous life cycle depending on how many hosts it feeds on in each cycle. I. pacificus has a four-stage life cycle that takes around 3 years to complete. These stages include egg, larva, nymph, and adult. They prefer dense woodland habitats or areas of brush and tall grass.
Babesia bovis is an Apicomplexan single-celled parasite of cattle which occasionally infects humans. The disease it and other members of the genus Babesia cause is a hemolytic anemia known as babesiosis and colloquially called Texas cattle fever, redwater or piroplasmosis. It is transmitted by bites from infected larval ticks of the order Ixodida. It was eradicated from the United States by 1943, but is still present in Mexico and much of the world's tropics. The chief vector of Babesia species is the southern cattle fever tick Rhipicephalus microplus.
Ticks of domestic animals directly cause poor health and loss of production to their hosts. Ticks also transmit numerous kinds of viruses, bacteria, and protozoa between domestic animals. These microbes cause diseases which can be severely debilitating or fatal to domestic animals, and may also affect humans. Ticks are especially important to domestic animals in tropical and subtropical countries, where the warm climate enables many species to flourish. Also, the large populations of wild animals in warm countries provide a reservoir of ticks and infective microbes that spread to domestic animals. Farmers of livestock animals use many methods to control ticks, and related treatments are used to reduce infestation of companion animals.
Transstadial transmission is the persistence of a symbiont or pathogen in an organism from one life stage ("stadium") to the next, such as larva to nymph to adult. This type of transmission is typically observed in insects. For example, the bacterium Borrelia burgdorferi, the causative agent for Lyme disease, infects the tick vector as a larva, with the infection maintained as the tick molts to a nymph and later develops as an adult. Transstadial transmission is also seen with other microbes such as other bacteria, fungi, and viruses in numerous insects. In addition to ticks, mites are another common vector. Transstadial transmission is especially relevant to public health, as several threats to public health are maintained in insect populations by transstadial transmission. Some debate exists regarding the classification of transstadial transmission as vertical transmission versus horizontal transmission. Reasons for this stem from further debate regarding transovarial transmission, described as the passage of a symbiont or pathogen from an infected female to its progeny, especially in eggs.
Anaplasma bovis is gram negative, obligate intracellular organism, which can be found in wild and domestic ruminants, and potentially a wide variety of other species. It is one of the last species of the Family Anaplasmaceae to be formally described. It preferentially infects host monocytes, and is often diagnosed via blood smears, PCR, and ELISA. A. bovis is not currently considered zoonotic, and does not frequently cause serious clinical disease in its host. This organism is transmitted by tick vectors, so tick bite prevention is the mainstay of A. bovis control, although clinical infections can be treated with tetracyclines. This organism has a global distribution, with infections noted in many areas, including Korea, Japan, Europe, Brazil, Africa, and North America.
Amblyomma variegatum, commonly known as the tropical bont tick, is a species of tick of the genus Amblyomma endemic to Africa. It has spread from its centre of origin to several countries, including the Caribbean islands, where it is known as the Senegalese tick and the Antigua gold tick. They are vividly coloured and have a substantial impact on livestock, primarily through their transmission of diseases. They are three-host hard ticks that have been found on a variety of domesticated species such as camels, cattle, goats, sheep, dogs, and various species of wildlife.
Flumethrin is a pyrethroid insecticide. It is used externally in veterinary medicine against parasitic insects and ticks on cattle, sheep, goats, horses, and dogs, and the treatment of parasitic mites in honeybee colonies.
Mites are small crawling animals related to ticks and spiders. Most mites are free-living and harmless. Other mites are parasitic, and those that infest livestock animals cause many diseases that are widespread, reduce production and profit for farmers, and are expensive to control.
Hyalomma dromedarii is a species of hard-bodied ticks belonging to the family Ixodidae.
Haemaphysalis bispinosa is a hard-bodied tick of the genus Haemaphysalis. It is found in India, Sri Lanka, Myanmar, Pakistan, Nepal, Australia, and Indonesia. It is an obligate ectoparasite of mammals. It is a potential vector of Kyasanur Forest disease virus. These ticks was found parasitized by a chalcid Hunterellus sagarensis in these diseased areas.
Rhipicephalus annulatus, the cattle tick, is a hard-bodied tick of the genus Rhipicephalus. It is also known as North American cattle tick, North American Texas fever tick, and Texas fever tick.
The zebra tick or yellow back tick is a species of hard tick. It is common in the Horn of Africa, with a habitat of the Rift Valley and eastward. It feeds upon a wide variety of species, including livestock, wild mammals, and humans, and can be a vector for various pathogens. The adult male has a distinctive black and ivory ornamentation on its scutum.