Flea Bites

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ber of international travelers to tropical destinations. The causative ectoparasite,. Tunga penetrans (a flea of approximately 1 mil- limeter of size), penetrates into ...
Flea Bites



pertussis, and tetanus (DPT1 and DPT3) and tuberculosis; 97 percent against measles; and 96 percent against polio and Haemophilus influenzae type B. HIV/AIDS does not present a major problem in Finland, and the current adult prevalence rate is less than 0.1 percent. Around 1,500 people are living with the disease, and it has proved fatal to less than 100. In May 2000, meningococcal disease was identified in Finland, and the country experienced outbreaks of influenza in 2003 and 2004. Severe acute respiratory syndrome (SARS) surfaced in spring 2003. The leading causes of death in Finland are cardiovascular disease, alcoholism-related conditions, and accidents. High cholesterol and obesity are also of grave concern. See Also: Childhood Immunization; Obesity. Bibliography. Central Intelligence Agency, “Finland,”

World Factbook www.cia.gov/cia/publications/factbook/ geos/fi.html; Commission on the Status of Women, “Finland” www.un.org/womenwatch/daw/Review/responses/ FINLAND-English.pdf (cited April 2007); Spencer Di Scala, Twentieth Century Europe: Politics, Society, Culture (McGraw-Hill, 2004); Sandra Halperin, War and Social Change in Modern Europe: The Great Transformation Revisited (Cambridge University Press, 2004); Martin A. Levin and Martin Shapiro, eds., Transatlantic Policymaking in an Age of Austerity: Diversity and Drift (Georgetown University Press, 2004); Jeremy Rifkin, The European Dream: How Europe’s Vision of the Future Is Quietly Eclipsing the American Dream (Jeremy P. Tarcher/Penguin, 2004); Social Security Administration, “Finland” www.ssa.gov/policy/docs/progdesc/ssptw/2002-2003/europe/finland.html (cited April 2007); Eric Solsten and Sandra W. Meditz, Finland: A Country Study (Federal Research Division, LOC, 1990); Peter Taylor-Gooby, New Risks, New Welfare: The Transformation of the European Welfare State (Oxford University Press, 2004). Elizabeth R. Purdy, Ph.D. Independent Scholar

Flea Bites A flea bite is the resulting injury from a flea sting, which could produce a local inflammatory reaction, or after an incubation period, a flea-borne disease,

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such as plague, endemic typhus fever, dipylidiasis, and hymenolepiasis, among others, but most species of flea do not transmit pathogens. Fleas belong (taxonomically) to the order Siphonapetra, with two important families for human and animal health: Pulicidae and Tungidae. The above-mentioned diseases are transmitted by members of family Pulicidae (Pulex, Ctenocephalides, and Xenopsylla). In history, Xenopsylla cheopis represented the most important vector of an ancient disease previously known as the Black Death (plague), one of the worst natural disasters in history. Plague or Black Death is an infection of rodents caused by Yersinia pestis and accidentally transmitted to humans by the bite of infected fleas. Plague has three forms: bubonic plague (infection of the lymph glands), septicemia plague (infection of the blood), and pneumonic plague (infection of the lungs). Pneumonic plague can spread from person to person. Fortunately, this disease is treatable with antibiotics if detected early. Prevention consists of controlling rodent fleas, educating the public and the medical community in places where plague occurs, and using preventive medicines and vaccines as appropriate. Endemic typhus fever or typhus (also called fleaborne typhus and murine typhus) is a disease caused by small bacteria called Rickettsia. Dipylidiasis is a common tapeworm infection of dogs and cats caused by Dipylidium caninum. Arthropods serve as intermediate hosts for this parasite, including then the fleas which include the dog flea (Ctenocephalides canis), the cat flea (C. felis), and the dog louse (Trichodectes canis). The risk to human beings to acquire this disease is low, because this occurs by ingestion of arthropod intermediate hosts which harbor the cysticercoid larvae. The hymenolepiasis, caused by the dwarf tapeworm or Hymenolepis nana, is the most common tapeworm infection diagnosed in the world. Although it is not the most common form of transmission, fleas could vectorize this disease in animals and may be in humans. People get infected by accidentally ingesting tapeworm eggs, by ingesting fecally contaminated foods and water, by touching the mouth with contaminated fingers, or by ingesting contaminated soil. Another important infection directly caused by fleas is the tungiasis which is a common health problem in economically depressed communities in South American and sub-Saharan African countries,

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Fluoride

but it should be considered in the increasing number of international travelers to tropical destinations. The causative ectoparasite, Tunga penetrans (a flea of approximately 1 millimeter of size), penetrates into the skin of its host, undergoes a peculiar hypertrophy, expels several hundred eggs for a period of less than three weeks, and eventually dies. Besides the human, this flea could infect cattle, sheep, and horses. SEE ALSO: Medical Entomology; Medical Helminthology;

Parasitic Diseases; Tick Bites.

Bibliography. Harold Brown, Clinical Parasitology (Ap-

pleton-Century-Crofts, 1983); Albert Camus, The Plague (Penguin, 1970); Gordon Cook and Alimuddin Zulma, Manson’s Tropical Diseases (Saunders, 2003); Hermann Feldmeier, “Severe Tungiasis in Underprivileged Communities: Case Series from Brazil,” Emerging Infectious Diseases (v.9/8, 2003); Becerri Flores and Romero Cabello, Medical Parasitology (McGraw-Hill, 2004); David Heymann, Control of Communicable Diseases in Man (APHA/ PAHO/WHO, 2004). Alfonso J. Rodriguez-Morales, M.D., M.Sc. Universidad de Los Andes, Venezuela Carlos Franco-Paredes, M.D., M.P.H. Emory University

Fluoride Fluoride is the ionic form of the element fluorine, and there are organic and inorganic compounds containing fluorine which form fluorides. Some of these are found naturally in low concentrations in drinking water and in tea and other foods, and indeed, the ocean itself has an average concentration of fluoride compounds of 1.3 parts per million. In industry, hydrofluoric acid is used for the etching of glass and also for the making of integrated circuit boards and other industrial applications. However, generally, in terms of healthcare, it is used to deal with prevention of tooth decay. In a very concentrated form, it can be a prescription drug as a part of drug molecules to resist the detoxification in the liver by the Cytochrome P450 oxidase.

Fluoride has been used for a long time in the treatment of teeth to prevent tooth decay, and is found in toothpaste. In 1951, Joseph C. Muhler and Harry G. Day of Indiana University reported that their research on stannous fluoride was an effective means of preventing tooth decay, and the university sold the research findings to Procter & Gamble who started using it in their Crest® toothpaste. Nowadays, fluoride is found in most toothpastes, and it is possible to use fluoride although care must be taken not to use too much, otherwise dental fluorosis could occur through overexposure. In addition, there has been much debate over water fluoridation with some parts of the world introducing it into water supplies to help reduce the level of tooth decay in children. This has led to widespread debate around the world with the World Health Organization and the American Dental Association recommending increasing the level of fluoride in water to between 0.7 and 1.2 parts per million. Opponents of water fluoridization claims that an increase in fluoride could weaken the human immune system, and this could lead to increased prevalence of certain diseases and disorders. However, most international health service agencies recognize that the benefits involved in the prevention of dental decay hugely outweigh the concerns that some people have expressed regarding the side effects. Articles on the role of fluoride and it possible side effects have been published in the British Medical Journal and also in forums such as The Journal of Fluorine Chemistry. This has not stopped politicians in many countries opposing the fluoridization of water, some of which involved several marathon debates in the British House of Commons, the latest of which was in November 2003. SEE ALSO: Dental Health. Bibliography. L. L. Demos, et al., “Water Fluoridation,

Osteoporosis, Fractures—Recent Developments,” Australian Dental Journal (v.46/2, 2001); M.S. McDonagh, et al., “Systematic Review of Water Fluoridation,” British Medical Journal (v.321, 2000); G.M. Whitford, “Fluoride in Dental Products,” Journal of Dental Research (v.66/5, 1987).

Justin Corfield Geelong Grammar School, Australia