South America is a continent in the Western Hemisphere in the Southern Hemisphere, with a small portion in the Northern Hemisphere. It may be considered a subcontinent of the Americas, how it is viewed in the Spanish and Portuguese-speaking regions of the Americas; the reference to South America instead of other regions has increased in the last decades due to changing geopolitical dynamics. It is bordered on the west on the north and east by the Atlantic Ocean, it includes twelve sovereign states, a part of France, a non-sovereign area. In addition to this, the ABC islands of the Kingdom of the Netherlands and Tobago, Panama may be considered part of South America. South America has an area of 17,840,000 square kilometers, its population as of 2016 has been estimated at more than 420 million. South America ranks fourth in fifth in population. Brazil is by far the most populous South American country, with more than half of the continent's population, followed by Colombia, Argentina and Peru. In recent decades Brazil has concentrated half of the region's GDP and has become a first regional power.
Most of the population lives near the continent's western or eastern coasts while the interior and the far south are sparsely populated. The geography of western South America is dominated by the Andes mountains. Most of the continent lies in the tropics; the continent's cultural and ethnic outlook has its origin with the interaction of indigenous peoples with European conquerors and immigrants and, more locally, with African slaves. Given a long history of colonialism, the overwhelming majority of South Americans speak Portuguese or Spanish, societies and states reflect Western traditions. South America occupies the southern portion of the Americas; the continent is delimited on the northwest by the Darién watershed along the Colombia–Panama border, although some may consider the border instead to be the Panama Canal. Geopolitically and geographically all of Panama – including the segment east of the Panama Canal in the isthmus – is included in North America alone and among the countries of Central America.
All of mainland South America sits on the South American Plate. South America is home to Angel Falls in Venezuela. South America's major mineral resources are gold, copper, iron ore and petroleum; these resources found in South America have brought high income to its countries in times of war or of rapid economic growth by industrialized countries elsewhere. However, the concentration in producing one major export commodity has hindered the development of diversified economies; the fluctuation in the price of commodities in the international markets has led to major highs and lows in the economies of South American states causing extreme political instability. This is leading to efforts to diversify production to drive away from staying as economies dedicated to one major export. South America is one of the most biodiverse continents on earth. South America is home to many interesting and unique species of animals including the llama, piranha, vicuña, tapir; the Amazon rainforests possess high biodiversity, containing a major proportion of the Earth's species.
Brazil is the largest country in South America, encompassing around half of the continent's land area and population. The remaining countries and territories are divided among three regions: The Andean States, the Guianas and the Southern Cone. Traditionally, South America includes some of the nearby islands. Aruba, Curaçao, Trinidad and the federal dependencies of Venezuela sit on the northerly South American continental shelf and are considered part of the continent. Geo-politically, the island states and overseas territories of the Caribbean are grouped as a part or subregion of North America, since they are more distant on the Caribbean Plate though San Andres and Providencia are politically part of Colombia and Aves Island is controlled by Venezuela. Other islands that are included with South America are the Galápagos Islands that belong to Ecuador and Easter Island, Robinson Crusoe Island, Chiloé and Tierra del Fuego. In the Atlantic, Brazil owns Fernando de Noronha and Martim Vaz, the Saint Peter and Saint Paul Archipelago, while the Falkland Islands are governed by the United Kingdom, whose sovereignty over the islands is disputed by Argentina.
South Georgia and the South Sandwich Islands may be associate
A health system sometimes referred to as health care system or as healthcare system, is the organization of people and resources that deliver health care services to meet the health needs of target populations. There is a wide variety of health systems around the world, with as many histories and organizational structures as there are nations. Implicitly, nations must design and develop health systems in accordance with their needs and resources, although common elements in all health systems are primary healthcare and public health measures. In some countries, health system planning is distributed among market participants. In others, there is a concerted effort among governments, trade unions, religious organizations, or other co-ordinated bodies to deliver planned health care services targeted to the populations they serve. However, health care planning has been described as evolutionary rather than revolutionary; the World Health Organization, the directing and coordinating authority for health within the United Nations system, is promoting a goal of universal health care: to ensure that all people obtain the health services they need without suffering financial hardship when paying for them.
According to WHO, healthcare systems' goals are good health for the citizens, responsiveness to the expectations of the population, fair means of funding operations. Progress towards them depends on how systems carry out four vital functions: provision of health care services, resource generation and stewardship. Other dimensions for the evaluation of health systems include quality, efficiency and equity, they have been described in the United States as "the five C's": Cost, Consistency and Chronic Illness. Continuity of health care is a major goal. Health system has been defined with a reductionist perspective, for example reducing it to healthcare system. In many publications, for example, both expressions are used interchangeably; some authors have developed arguments to expand the concept of health systems, indicating additional dimensions that should be considered: Health systems should not be expressed in terms of their components only, but of their interrelationships. The World Health Organization defines health systems as follows: A health system consists of all organizations and actions whose primary intent is to promote, restore or maintain health.
This includes efforts to influence determinants of health as well as more direct health-improving activities. A health system is therefore more than the pyramid of publicly owned facilities that deliver personal health services, it includes, for example, a mother caring for a sick child at home. It includes inter-sectoral action by health staff, for example, encouraging the ministry of education to promote female education, a well known determinant of better health. Healthcare providers are individuals providing healthcare services. Individuals including health professionals and allied health professions can be self-employed or working as an employee in a hospital, clinic, or other health care institution, whether government operated, private for-profit, or private not-for-profit, they may work outside of direct patient care such as in a government health department or other agency, medical laboratory, or health training institution. Examples of health workers are doctors, midwives, paramedics, medical laboratory technologists, psychologists, chiropractors, community health workers, traditional medicine practitioners, others.
There are five primary methods of funding health systems: general taxation to the state, county or municipality national health insurance voluntary or private health insurance out-of-pocket payments donations to charitiesMost countries' systems feature a mix of all five models. One study based on data from the OECD concluded that all types of health care finance "are compatible with" an efficient health system; the study found no relationship between financing and cost control. The term health insurance is used to describe a form of insurance that pays for medical expenses, it is sometimes used more broadly to include insurance covering disability or long-term nursing or custodial care needs. It may be provided from private insurance companies, it may be purchased by individual consumers. In each case premiums or taxes protect the insured from unexpected health care expenses. By estimating the overall cost of health care expenses, a routine finance structure can be developed, ensuring that money is available to pay for the health care benefits specified in the insurance agreement.
The benefit is administered by a government agency, a non-profit health fund or a
Nigeria the Federal Republic of Nigeria, is a federal republic in West Africa, bordering Niger in the north, Chad in the northeast, Cameroon in the east, Benin in the west. Its coast in the south is located on the Gulf of Guinea in the Atlantic Ocean; the federation comprises 36 states and 1 Federal Capital Territory, where the capital, Abuja, is located. The constitution defines Nigeria as a democratic secular country. Nigeria has been home to states over the millennia; the modern state originated from British colonial rule beginning in the 19th century, took its present territorial shape with the merging of the Southern Nigeria Protectorate and Northern Nigeria Protectorate in 1914. The British set up administrative and legal structures while practising indirect rule through traditional chiefdoms. Nigeria became a formally independent federation in 1960, it experienced a civil war from 1967 to 1970. It thereafter alternated between democratically elected civilian governments and military dictatorships until it achieved a stable democracy in 1999, with the 2011 presidential election considered the first to be reasonably free and fair.
Nigeria is referred to as the "Giant of Africa", owing to its large population and economy. With 186 million inhabitants, Nigeria is the most populous country in Africa and the seventh most populous country in the world. Nigeria has the third-largest youth population in the world, after India and China, with more than 90 million of its population under age 18; the country is viewed as a multinational state as it is inhabited by 250 ethnic groups, of which the three largest are the Hausa and Yoruba. The official language is English. Nigeria is divided in half between Christians, who live in the southern part of the country, Muslims, who live in the north. A minority of the population practice religions indigenous to Nigeria, such as those native to the Igbo and Yoruba ethnicities; as of 2015, Nigeria is the world's 20th largest economy, worth more than $500 billion and $1 trillion in terms of nominal GDP and purchasing power parity respectively. It overtook South Africa to become Africa's largest economy in 2014.
The 2013 debt-to-GDP ratio was 11 percent. Nigeria is considered to be an emerging market by the World Bank. However, it has a "low" Human Development Index, ranking 152nd in the world. Nigeria is a member of the MINT group of countries, which are seen as the globe's next "BRIC-like" economies, it is listed among the "Next Eleven" economies set to become among the biggest in the world. Nigeria is a founding member of the African Union and a member of many other international organizations, including the United Nations, the Commonwealth of Nations and OPEC; the name Nigeria was taken from the Niger River running through the country. This name was coined in the late 19th century by British journalist Flora Shaw, who married Lord Lugard, a British colonial administrator; the origin of the name Niger, which applied only to the middle reaches of the Niger River, is uncertain. The word is an alteration of the Tuareg name egerew n-igerewen used by inhabitants along the middle reaches of the river around Timbuktu prior to 19th-century European colonialism.
The Nok civilisation of Northern Nigeria flourished between 500 BC and AD 200, producing life-sized terracotta figures that are some of the earliest known sculptures in Sub-Saharan Africa. Further north, the cities Kano and Katsina have a recorded history dating to around 999 AD. Hausa kingdoms and the Kanem–Bornu Empire prospered as trade posts between North and West Africa; the Kingdom of Nri of the Igbo people consolidated in the 10th century and continued until it lost its sovereignty to the British in 1911. Nri was ruled by the Eze Nri, the city of Nri is considered to be the foundation of Igbo culture. Nri and Aguleri, where the Igbo creation myth originates, are in the territory of the Umeuri clan. Members of the clan trace their lineages back to the patriarchal king-figure Eri. In West Africa, the oldest bronzes made using the lost-wax process were from Igbo-Ukwu, a city under Nri influence; the Yoruba kingdoms of Ife and Oyo in southwestern Nigeria became prominent in the 12th and 14th centuries, respectively.
The oldest signs of human settlement at Ife's current site date back to the 9th century, its material culture includes terracotta and bronze figures. Oyo, at its territorial zenith in the late 17th to early 18th centuries, extended its influence from western Nigeria to modern-day Togo; the Edo's Benin Empire is located in southwestern Nigeria. Benin's power lasted between the 19th centuries, their dominance reached further. At the beginning of the 19th century, Usman dan Fodio directed a successful jihad and created and led the centralised Fulani Empire; the territory controlled by the resultant state included much of modern-day northern and central Nigeria. For centuries, various peoples in modern-day Nigeria traded overland with traders from North Africa. Cities in the area became regional centres in a broad network of trade routes that spanned western and northern Africa. In the 16th century, Portuguese explorers were the first Europeans to begin significant, direct trade with peoples of modern-day Nigeria, at the port they named Lago
Reconstructive surgery is, in its broadest sense, synonymous with plastic surgery. However, reconstructive surgery is understood as the use of surgery to restore the form and function of the body, which does not include aesthetic or cosmetic surgery. For example, plastic surgeons, maxillo-facial surgeons and otolaryngologists do reconstructive surgery on faces after trauma and to reconstruct the head and neck after cancer. Other branches of surgery perform some reconstructive procedures; the common feature is that the operation attempts to restore the anatomy or the function of the body part to normal. Reconstructive surgeons use the concept of a reconstructive ladder to manage complex wounds; this ranges from simple techniques such as primary closure and dressings to more complex skin grafts, tissue expansion and free flaps. Cosmetic surgery procedures include breast enhancement and lift, face lift, forehead lift and lower eyelid surgery, laser skin resurfacing, chemical peel, nose reshaping, reconstruction liposuction, nasal reconstruction using the paramedian flap, as well as tummy tuck.
Many of these procedures are being improved. In 2010 only 10 research papers were identified which looked at reconstructive surgery after massive weight loss. Recent literature in medline has noted implementation of barbed suture in these procedures. Biomaterials are, in their simplest form, plastic implants used to correct or replace damaged body parts. Biomaterials were not used for reconstructive purposes until after World War II due to the new and improved technology and the tremendous need for the correction of damaged body parts that could replace transplantation; the process involves scientific and medical research to ensure that the biomaterials are biocompatible and that they can assume the mechanical and functioning roles of the components they are replacing. A successful implantation can best be achieved by a team that understands not only the anatomical, physiological and pathological aspects of the problem, but comprehends bioengineering. Cellular and tissue engineering is crucial to know for reconstructive procedures.
An overview on the standardization and control of biomedical devices has been gathered by D. G. Singleton. Papers have covered in depth the U. S. Food and Drug Administration Premarket Approval Process and FDA regulations governing Class III devices. Two papers have described how the National Bureau of Standards, American Dental Association, National Institute of Dental Research, private dental companies have collaborated in a number of important advances in dental materials and analytical systems
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti
Auschwitz concentration camp
The Auschwitz concentration camp was a complex of more than 40 Nazi concentration camps and extermination camps built and operated by Nazi Germany in occupied Poland during World War II and the Holocaust. It consisted of the main camp and administrative headquarters in Oświęcim. Germany invaded Poland in September 1939, sparking World War II, they converted Auschwitz I from an army barracks to a prison camp for Polish political prisoners; the first prisoners were German criminals who were brought to the camp as functionaries in May 1940, the first gassing of prisoners took place in block 11 of Auschwitz I in September 1941. Auschwitz II–Birkenau became a major site of the Nazis' Final Solution to the Jewish Question. Transport trains delivered Jews from all over German-occupied Europe to the camp's gas chambers from early 1942 until late 1944. At least 1.1 million people died at Auschwitz of the estimated 1.3 million sent there, some 90 percent of them were Jews. One in six Jews killed in the Holocaust died at the camp.
Others deported to Auschwitz included 150,000 non-Jewish Poles, 23,000 Roma, 15,000 Soviet prisoners of war, 400 Jehovah's Witnesses, tens of thousands of diverse nationalities, an unknown number of homosexual men. Many of those not killed in the gas chambers died because of starvation, forced labor, infectious diseases, individual executions, medical experiments. In the course of the war, the camp was staffed by 7,000 members of the German Schutzstaffel 12 percent of whom were convicted of war crimes. Several were executed, including camp commandant Rudolf Höss; the Allies did not act on early reports of atrocities, their failure to bomb it or its railways remains controversial. At least 802 prisoners tried to escape, 144 and two Sonderkommando units launched a brief, unsuccessful uprising on 7 October 1944, consisting of prisoners assigned to staff the gas chambers. Soviet troops approached Auschwitz in January 1945, most of the prisoners were sent west on a death march; the remaining prisoners were liberated on 27 January 1945, a day commemorated as International Holocaust Remembrance Day.
In the following decades, survivors wrote memoirs of their experiences in Auschwitz, such as Primo Levi, Viktor Frankl, Elie Wiesel, the camp became a dominant symbol of the Holocaust. In 1947, Poland founded the Auschwitz-Birkenau Memorial and Museum on the site of Auschwitz I and II, it was named a World Heritage Site by UNESCO in 1979; the ideology of Nazism brought together elements of antisemitism, racial hygiene and eugenics, combined them with pan-Germanism and territorial expansionism with the goal of obtaining more Lebensraum for the Germanic people. After the Nazi seizure of power in Germany, boycotts of German Jews and acts of violence against them became ubiquitous, legislation was passed excluding them from the civil service and certain professions, including the law. Harassment and economic pressure were used to encourage them to leave Germany. On 15 September 1935, the Reichstag passed the Nuremberg Laws, prohibiting marriages between Jews and people of Germanic extraction, extramarital relations between Jews and Germans, the employment of German women under the age of 45 as domestic servants in Jewish households.
The Reich Citizenship Law defined as citizens those of "German or kindred blood". Thus Jews and other minorities were stripped of their citizenship. By the start of World War II in 1939, around 250,000 of Germany's 437,000 Jews had emigrated to the United States, the United Kingdom, other countries; when Germany invaded Poland in September 1939, triggering World War II, Adolf Hitler ordered that the Polish leadership and intelligentsia be destroyed. 65,000 civilians, viewed as inferior to the Aryan master race, had been killed by the end of 1939. In addition to leaders of Polish society, the Nazis killed Jews, the Roma, the mentally ill. SS-Obergruppenführer Reinhard Heydrich head of the Gestapo, ordered on 21 September 1939 that Polish Jews be rounded up and concentrated into cities with good rail links; the intention was to deport them to points further east, or to Madagascar. Two years in June 1941, in an attempt to obtain new territory, Hitler invaded the Soviet Union. Auschwitz I, a former Polish army barracks, was the main camp and administrative headquarters of the camp complex.
Intending to use it to house political prisoners, Reichsführer-SS Heinrich Himmler, head of the Schutzstaffel, approved the site in April 1940 on the recommendation of SS-Obersturmbannführer Rudolf Höss of the Concentration Camps Inspectorate. Höss oversaw the development of the camp and served as its first commandant, with SS-Obersturmführer Josef Kramer as his deputy. Around 1,000 m long and 400 m wide, Auschwitz I consisted of 20 brick buildings, six of them two-story; the camp housed the SS by 1943 held 30,000 inmates. The first 30 prisoners arrived on 20 May 1940 after being transported from the Sachsenhausen concentration camp in Oranienburg, Germany. Convicted German criminals, the men were known as "greens" after the green triangles they were required to w
Borrelia is a genus of bacteria of the spirochete phylum. It causes borreliosis, a zoonotic, vector-borne disease transmitted by ticks and by lice, depending on the species of bacteria; the genus is named after the French biologist Amédée Borrel who first documented the distinction between a species of Borrelia, B. anserina, the other known type of spirochete at the time, Treponema pallidum. This bacteria must be viewed using dark field microscopy, which make the cells appear white against a dark background. Borrelia is grown in a medium called Barbour-Stoenner-Kelly medium. There are 52 known species of Borrelia; the Lyme disease group has been moved to their own genus, but this change is not yet accepted. This bacteria uses hard and soft ticks and lice as vectors Testing for the presence of the bacteria in a human includes two-tiered serological testing, including immunoassays and immunoblotting. Borrelia is a member of the Spirochaetacaea family and therefore present the characteristic spirochete shape.
Most species of Borrelia are obligate anaerobes. Borrelia has an outer membrane that contains a substance similar to lipopolysaccharides, an inner membrane, a layer of peptidoglycan in a periplasmic space, which classifies them as Gram-negative. However, this result is not visualized using Gram staining. Borrelia are 20-30 um long and 0.2-0.3 um wide. Spirochetes move using; the filaments rotate in this space, between the outer membrane and the peptidoglycan layer, propelling the bacterium forward in a corkscrew-like motion. The outer membrane of Borrelia contains outer surface proteins; the accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature and National Center for Biotechnology Information and the phylogeny is based on 16S rRNA-based LTP release 111 by'The All-Species Living Tree' Project. Notes: ♦ Type strain lost or not available ♠ Strains found at the National Center for Biotechnology Information but not listed in the List of Prokaryotic names with Standing in Nomenclature ♥ Strains not lodged at National Center for Biotechnology Information or listed in the List of Prokaryotic names with Standing in Nomenclature Ticks Hard ticks of the genus Ixodidae are common vectors of Borellia bacteria and are the only type of ticks that have been shown to transmit Lyme disease bacteria to humans.
Other species are carried by soft ticks. The soft tick Ornithodoros carries the species of Borellia. Another species, B. anserina is carried by the soft tick Argas. Inside the ticks, the bacteria grows in the midgut and travels to the salivary glands to be transmitted to a new host. Ticks can spread the bacteria to each other. If an animal has been infected by a tick and is bit by a second tick, the second tick can become infected; the bacteria is most transmitted to humans through ticks in the nymph stage of development, because they are smaller and less to be noticed and removed. The ticks must have around 36 to 48 hours of contact with a host in order to transmit the bacteria. Lice Lice that feed on infected humans acquire the Borrelia organisms that multiply in the hemolymph and gut of the louse; when an infected louse feeds on an uninfected human, the organism gains access when the victim crushes the louse or scratches the area where the louse is feeding. The Center for Disease Control reported that there is no credible evidence that lice can carry Borrelia.
Of the 52 known species of Borrelia, 21 are known to cause Lyme disease or borreliosis and are transmitted by ticks. The major Borrelia species causing Lyme disease are Borrelia burgdorferi, Borrelia afzelii, Borrelia garinii. All species that cause Lyme disease are referred to collectively as B. burgdorferi sensu lato, while B. burgdorferi itself is specified as B. burgdorferi senso stricto. B. burgdorferi was believed to be the only species to cause Lyme disease in the US, with the other two existing only in Europe and Asia, but a new species called B. mayonii has caused Lyme disease in the US as well. Relapsing fever borreliosis occurs with severe bacteremia. There are 25 species of Borrelia that are known to cause relapsing fever While most species use the soft tick Argasidae as their vector, there are some outliers that live in hard ticks or lice. Relapsing fever can be spread epidemically through endemically through ticks. B. Recurrentis, a common species underlying relapsing fever, is transmitted by the human body louse.
B. recurrentis infects the person via mucous membranes and invades the bloodstream. Other tick-borne relapsing infections are acquired from other species, such as B. hermsii, B. parkeri, or B. miyamotoi, which can be spread from rodents, serve as a reservoir for the infection, via a tick vector. B. hermsii and B. recurrentis cause similar diseases, although the disease associated with B. hermsii has more relapses and is responsible for more fatalities, while the disease caused by B. recurrentis has longer febrile and afebrile intervals and a longer incubation period. Direct tests include culture of Borrelia from skin, blood, or cerebrospinal fluid and detection of genetic material by polymerase chain reaction in skin, blood, or synovial fluid. Two-tiered serological testing is performed for differential diagnosis of Borrelia infection; the first-t