(fē′vĕr)

[L. febris, fever]

1. An abnormal elevation of temperature. The normal temperature taken orally ranges from about 97.6° to 99.6°F (36.3°C to 37.6°C). Rectal temperature is 0.5° to 1.0°F higher than oral temperature. Normal temperature fluctuates during the day and is lowest in the morning and highest in the late afternoon; these variations are maintained during a fever. The expended basal energy is estimated to be increased about 12% for each degree centigrade of fever.
SYN: SEE: pyrexia
SEE: basal energy expenditure; SEE: temperature

CAUSES
Fever is caused by the release of interleukin-1 (IL-1), interleukin-2 (IL-2), and tumor necrosis factor from white blood cells (esp. macrophages), secretion of acute phase proteins, and redistribution of the blood away from the skin by the autonomic nervous system. The body cools itself and returns its temperature to normal range by diaphoresis (sweating). Elevated temperature caused by inadequate thermoregulatory responses during exercise in very hot weather is called hyperthermia; the set point is not increased. Infections, drugs, tumors, breakdown of necrotic tissue, CNS damage, and collagen diseases are the underlying causes of fevers. Despite common beliefs, fever is not harmful except for patients who cannot tolerate its hypermetabolic effects, for some older patients in whom it can cause delirium, and for children with a history of febrile seizures.

SYMPTOMS AND SIGNS
The patient may feel hot and will have an increased body temperature. Other physical findings may include chills, sweating, rashes, organomegaly, painful joints, and murmurs.

DIAGNOSIS
Fever is a rectal temperature higher than 38°C (100.4°F), oral temperature higher than 37.5°C (99.5°F), or axillary temperature higher than 37°C (98.6°F). Fever is categorized as follows: fever of short duration with localizing signs; fever without localizing signs and with a duration of less than 1 week; and fever of unknown origin (FUO) with a duration of more than 14 days that remains undiagnosed.

TREATMENT
Depending on the underlying cause and level of the illness, the treatment of fever will vary. Plenty of fluids and rest should be provided; ibuprofen, aspirin, or acetaminophen may be given.

PATIENT CARE
Patients with fever frequently seek professional medical attention. Fever is often an important indicator of infections or inflammations that may cause significant injury if left untreated. Diagnosing the cause of a fever may lead to specific therapies that limit the duration of an illness and prevent secondary organ damage or even death. The suppression of fever, however, is controversial. Some believe that fever helps to eradicate infecting organisms that cannot survive in a hot environment. Nonetheless, medications such as acetaminophen, aspirin, and nonsteroidal anti-inflammatory drugs (NSAIDs) can lower body temperatures in febrile patients and are commonly used, esp. if the body temperature exceeds 101°F (38.3°C). It is unknown whether using antipyretics results in improvements in survival or decreases in morbidity. In some settings, e.g., the care of the hospice patient with a fever, withholding an antipyretic drug is considered to be inadequate symptom management by most health care providers. In other settings, e.g., in patients with malignant hyperthermia or heatstroke, giving antipyretics represents a standard of care. To date, however, controlled trials of withholding antipyretics in many illnesses have not been performed.

Suppression of fever (by induced hypothermia) is recommended for those who have suffered stroke or persistent seizures; however, proof of the effectiveness of lowering the body temperature of stroke victims is based on laboratory data rather than clinical effectiveness. Suppression of fever in young children with viral or bacterial infections is often a comfort for them; yet some researchers have speculated about adverse effects of this common practice, e.g., whether there is a link to suppression of fever and autistic disorders. When the choice is made to suppress a fever, it is probably most comfortable to give antipyretics on a regular basis (every 4 or 6 hr) rather than intermittently. Intermittent dosing of antipyretics may produce alternating bouts of chills and sweats, which most patients find unpleasant. Some patients may never mount a fever; this is particularly true of those over 65, who may have serious treatable infections without elevations of body temperature. In older patients, the first indication of inflammatory or infectious illnesses may be a cough, lethargy, anorexia, or alterations in mental status.

Aspirin and other salicylates are contraindicated as antipyretics or analgesics in children because of their association with an increased risk of Reye syndrome. Public and parental education should be provided to make certain this knowledge is widely disseminated.

2. A disease characterized by fever.

acute pharyngoconjunctival fever

ABBR: APC An acute disease consisting of fever, pharyngitis, and conjunctivitis. Treatment is symptomatic.

African tick bite fever

A disease transmitted to humans by ticks of the genus Amblyomma infected with Rickettsia africae. The disease is found in sub-Saharan Africa and the French West Indies and is characterized by fevers, headache, muscle pain, scabs that form at the site of tick inoculation, and localized lymph node swelling.

Alkhurma hemorrhagic fever

ABBR: AHFV A tick-borne hemorrhagic fever caused by a flavivirus, first identified on the Arabian peninsula.

biphasic fever

An illness characterized by an early elevation in body temperature followed by a later one. It is often caused by systemic bacterial infection.

blackwater fever

Hemoglobinuria (bloody urine) that occurs as a complication of falciparum malaria infection. It is the result of red blood cell destruction and the release of hemoglobin. It occurs most commonly in patients who have been treated with drugs derived from quinine.
SEE: falciparum malaria

SYMPTOMS
The illness is marked by high fevers, dark urine, epigastric pain, vomiting, jaundice, and shock. Physical findings include enlargement of the liver and spleen. Laboratory hallmarks include severe anemia and, occasionally, renal failure.

boutonneuse fever

SEE: Mediterranean spotted fever.

brain fever

SEE: Meningitis.

breakbone fever

SEE: Dengue.

Canefield fever

SEE: Leptospirosis.

childbed fever

SEE: Puerperal sepsis.

Colorado tick fever

A form of encephalitis found almost exclusively in the western U.S. and Canada, caused by a coltivirus transmitted to human beings by the bite of infected Dermacentor andersoni adult or nymph ticks. The disease is usually identified in spring and summer, typically in middle-aged men. Common symptoms include fevers, chills, headache, and muscle aches.
SEE: Colorado tick fever virus; SEE: coltivirus

Congo-Crimean viral hemorrhagic fever

Crimean-Congo viral hemorrhagic fever A frequently fatal viral infection found in the Middle East, Africa, and southwestern Asia, characterized by bleeding, diarrhea, hepatitis, high fevers, throat pain, and vomiting. The cause is the Congo-Crimean hemorrhagic fever virus, which is transmitted to humans by Ixodes ticks or exposure to the blood of infected animals or patients. Ribavirin has been used empirically to treat the disease in some patients.

continuous fever

A sustained fever, as in scarlet fever, typhus, or pneumonia, with a slight diurnal variation.

cotton fever

A generic term for transient fevers and other septic symptoms in injection drug users who use cotton to filter heroin before injecting the drug. The symptoms arise from a reaction to bacterial endotoxins contaminating cotton fibers.

dandy fever

SEE: Dengue.

deer fly fever

SEE: Tularemia.

dengue fever

SEE: Dengue.

dengue hemorrhagic fever

ABBR: DHF A grave sequela of dengue, marked by fever, headache, myalgia, arthralgias, rash, spontaneous bleeding, increased blood vessel permeability to proteins, and low platelet counts (<100,000/mm³).

desert fever

SEE: Coccidioidomycosis.

drug fever

Fever caused by the administration of a drug. The diagnosis of drug fever may be overlooked initially because fevers are more often caused by infections, rheumatological illnesses, or malignancies. Classically, the fever is present when a drug is given, stops when the drug is stopped, and returns when the patient is re-exposed to the drug.

Ebola virus hemorrhagic fever

An often fatal viral disease that appears in sporadic outbreaks in Africa. The clinical presentation of widespread bleeding into many organs and fever is similar to that seen in Lassa fever, Marburg virus disease, and Congo-Crimean viral hemorrhagic fever.
Like other hemorrhagic viruses Ebola virus requires maximal infection control and biocontainment, i.e., biosafety level 4.

CAUSES
The disease is caused by one of five species of Ebola virus of the Filoviridae family, distinguished by long threadlike strands of RNA. These species include: Bundibugyo ebolavirus (BDBV), Reston ebolavirus (RESTV), Sudan ebolavirus (SUDV), Taï Forest ebolavirus (TAFV), and Zaire ebolavirus (EBOV). The animal host has not been identified, which limits study of the disease. In each outbreak, the first human infection is believed to be caused by a bite from an infected animal. Subsequent cases are the result of contact with blood or body secretions from an infected person or the reuse of contaminated needles and syringes.

SYMPTOMS AND SIGNS
The incubation period of 2 to 3 weeks is followed by sudden onset of high fever, myalgia, diarrhea, headache, fatigue, and abdominal pain; a rash, sore throat, and conjunctivitis may be present. Within 7 days, shock develops, usually associated with hemorrhage; more than 50% of patients die. The patient is infectious after fever appears.

DIAGNOSIS
Ebola virus infection can be detected by real-time polymerase chain reaction testing of blood and body fluids and by serology to detect IgM and IgG against the virus.

PATIENT CARE
The use of standard barrier precautions prevents transmission, with the addition of leg and shoe covers if large amounts of blood, vomit, or diarrhea are present; negative-pressure isolation rooms are used if available. The spread of Ebola virus between humans by airborne droplets has not been documented, but face masks are recommended if the patient has respiratory symptoms. All equipment must be sterilized before reuse.

enteric fever

SEE: Typhoid fever.

epidemic hemorrhagic fever

SEE: Hemorrhagic nephrosonephritis.

factitious fever

Fever produced artificially by a patient. This is done by heating the thermometer or by self-administering pyrogenic substances. An artificial fever may be suspected if the pulse rate is much lower than expected for the degree of fever noted. This diagnosis should be considered in all patients in whom there is no other plausible explanation for the fever. Patients who pretend to have fevers may have serious psychiatric problems.
SEE: factitious disorder; SEE: malinger; SEE: Munchausen syndrome

familial Hibernian fever

A rare autosomal dominant syndrome characterized by intermittent elevations of body temperature, muscle pains, abdominal pain, inguinal hernias, and rash.
SYN: SEE: TNF receptor-associated periodic syndrome

familial Mediterranean fever

ABBR: FMF An autosomal recessive disorder in which patients suffer repeated febrile illnesses without evidence of infection. It occurs most often in people of Middle Eastern or Italian descent. Symptomatic attacks typically begin in children between 5 and 15 and often consist of fever, joint pains, abdominal pain resembling peritonitis, pleurisy or pericarditis, and rashes (although individual symptoms may vary). Duration and frequency of the attacks can be unpredictable. About 40% of patients ultimately develop amyloidosis. It can be treated with colchicine.
SYN: SEE: periodic fever; SEE: recurrent polyserositis

Flinders Island spotted fever

ABBR: FISF A spotted fever transmitted to humans by the bite of Ixodes ticks infected with Ricksettsia honei. It is found primarily in Victoria and Tasmania, Australia, and is similar to Rocky Mountain spotted fever in the U.S.

Fort Bragg fever

SEE: Pretibial fever.

Gibraltar fever

SEE: Brucellosis.

grain fever

SEE: Silo-filler's disease.

Guama fever

A mosquito-borne encephalitis, transmitted by a bunyavirus.

Haverhill fever

SEE: Rat-bite fever.

hay fever

A seasonal illness, marked by sneezing, sniffling, runny nose, and itchy or watery eyes. This condition, which affects 10% to 20% of the U.S. population, results from a type I hypersensitivity reaction involving the mucous membranes of the nose and upper air passages. It is the most common manifestation of atopic (inherited) allergy.
SYN: SEE: allergic rhinitis; SEE: pollinosis
SEE: allergen; SEE: allergy; SEE: desensitization

CAUSES
Airborne pollens, fungal spores, dust, and animal dander cause hay fever. It is most commonly triggered in the spring by pollen from trees, in the summer by grass pollen, and in the fall by pollen from wildflowers, e.g., ragweed. Nonseasonal rhinitis may result from inhalation of animal dander, dust from hay or straw, or house dust mites.

TREATMENT
Seasonal usage of antihistamines, cromolyn, and corticosteroid nasal sprays are the usual therapy in the U.S. Prophylaxis through desensitization is also useful but is less convenient and usually more expensive. Avoiding allergens is also effective but not always possible.

Overuse of corticosteroids may damage the nasal mucosa, and absorption of the drug can cause adverse side effects.

humidifier fever

Allergic alveolitis caused by exposure to inhaled antigens and marked by flulike symptoms.
SEE: alveolitis
SYN: SEE: humidifier lung

induced fever

Fever produced artificially to treat certain diseases such as central nervous system syphilis. A sustained fever of 105°F (40.5°C), or even higher, maintained for 6 to 8 or 10 hr may be induced by medical diathermy or injection of malarial parasites.

inhalation fever

Any respiratory or immunological illness that results from breathing in bacteria, dust, fumes, fungi, or other aerosolized toxins. Examples include humidifier fever and metal fume fever.

intermittent fever

Fever in which symptoms disappear completely between paroxysms.
SEE: malaria; SEE: undulant fever

Japanese spotted fever

A spotted fever transmitted to humans by the bite of Ixodes ticks infected with Rickettsia japonica. The disease has been identified mostly in Japan and Korea.

Karelian fever

SEE: Ockelbo disease.

Katayama fever

A systemic allergic reaction to invasion of the body by Schistosoma larvae. It is marked by fevers, an urticarial rash, cough, enlargement of the lymph nodes and viscera, and eosinophilia.

Korean hemorrhagic fever

SEE: Hemorrhagic nephrosonephritis.

Lassa fever

A potentially lethal viral hemorrhagic fever endemic in West Africa.

CAUSES
It is caused by an arenavirus that humans contract after contact with infected rodents (or their excretions).

INCIDENCE
Between 100,000 and 300,000 people are infected annually.

SYMPTOMS AND SIGNS
Common symptoms include fever, sore throat, headache, nausea, diarrhea, joint and muscle pain; bleeding or hearing loss occasionally complicate the illness.

DIAGNOSIS
The disease may be diagnosed with viral cultures or real-time polymerase chain reaction.

TREATMENT
Supportive nursing care is sufficient for most patients. Ribavirin given in the first week of illness and continued for 10 days has been very effective in reducing the death rate. This medicine should also be given orally for 10 days prophylactically to those who have been percutaneously exposed to the virus. Patients are isolated in special isolation units that filter the air leaving the room and maintain negative pressure. All sputum, blood, excreta, and objects that the patient has handled are disinfected.

PREVENTION
Patients suspected of having Lassa fever, or those with proven infection, should be isolated from others. Respiratory, blood, body fluid, and biosafety precautions should be imposed. Patients should avoid sexual intercourse with partners for several months after infection clears.

IMPACT ON HEALTH
Many infections with Lassa fever cause only mild symptoms, but multiple organ system failure and shock may complicate infection. Between 1% and 2% of infected patients die of the disease.

PATIENT CARE
Lassa virus infection poses the highest level of safety concerns to caregivers and contacts of infected patients because it may be transmitted from person to person and may be lethal. Lassa fever is therefore considered a biosafety level 4 virus (requiring the most stringent isolation procedures of any pathogen). Similar biosafety level 4 virus infections include Crimean-Congo hemorrhagic fever, Ebola virus, Hantavirus, and Marburg virus. Up-to-date information about containment of biosafety level 4 viruses can be obtained from the Centers for Disease Control and Prevention, Special Pathogens Branch.

Malta fever

SEE: Brucellosis.

Mediterranean fever

SEE: Brucellosis.

Mediterranean spotted fever

An infectious, occasionally fatal illness transmitted to humans by ticks infected with Rickettsia conorii. The disease is clinically similar to Rocky Mountain spotted fever.
SYN: SEE: boutonneuse fever

metal fume fever

A syndrome resembling influenza, produced by inhalation of excessive concentrations of metallic oxide fumes such as zinc oxide or antimony, arsenic, brass, cadmium, cobalt, copper, iron, lead, magnesium, manganese, mercury, nickel, or tin. It occurs in those whose occupations expose them to these metals.
SEE: polymer fume fever

SYMPTOMS AND SIGNS
The onset of symptoms is usually delayed. Chills, weakness, lassitude, and profound thirst occur, followed some hours later by sweating and anorexia. Occasionally, there is mild inflammation of the eyes and respiratory tract. The symptoms are more acute at the beginning of the work week than at the end. This is felt to be attributable to the individual's adapting to the fumes as exposure continues.

FIRST AID
Therapy includes analgesics, antipyretics, and rest.

milk fever

A veterinary term, no longer used in clinical medicine, for an elevation in body temperature and paralysis occurring after a cow gives birth.
SYN: SEE: paresis puerperalis

monkey fever

A colloquial and imprecise name given to Kyasanur Forest disease.
SEE: Kyasanur Forest disease

neutropenic fever

Fever associated with an abnormally low neutrophil level, usually caused by infection. This condition is treated with empirical antibiotic therapy pending the results of cultures. Neutropenia has many causes, including chemotherapy, radiation exposure, aplastic anemia, bone marrow infiltration from malignancy, and complications of bone marrow transplantation. The risk of potentially life-threatening infection is substantial when the absolute neutrophil count is below 500/mm³.

Oroya fever

A clinical form of bartonellosis. It is an acute, potentially life-threatening disease endemic in Peru and other South American countries, characterized by high intermittent fever, lymphadenopathy, severe anemia, and pains in the joints and long bones. If untreated, the fever has a 10% to 90% fatality rate.
SEE: bartonellosis

pappataci fever

SEE: Sandfly fever.

paratyphoid fever

A rare form of febrile gastroenteritis in Western societies, marked by fevers, abdominal pain, diarrhea, headache, and occasionally intestinal perforation. It is caused by Salmonella paratyphi (A and B strains) and related Salmonella species and is typically contracted by travelers who have visited tropical countries. Antibiotic treatments include ciprofloxacin or chloramphenicol.

parrot fever

SEE: Psittacosis.

Pel-Ebstein fever

SEE: Pel-Ebstein fever

periodic fever

1. A fever that recurs at regular intervals, e.g., every second, third, or fourth day. SEE: 2. Familial Mediterranean fever.

phlebotomus fever

SEE: Sandfly fever.

polymer fume fever

A condition caused by breathing fumes produced by certain polymers heated over 300°C (570°F).

SYMPTOMS AND SIGNS
Symptoms include a tight gripping sensation of the chest, shivering, sore throat, fever, and weakness.

TREATMENT
Avoidance of the fumes is the treatment.

SEE: metal fume fever

Pontiac fever

An infection with Legionella species that causes fevers, chills, headache, muscle aches, (GI) upset, and prostration, but not pneumonia.

pretibial fever

A form of leptospirosis caused by one of the several serotypes of the autumnalis serogroup. It is characterized by fever, a rash on the legs, prostration, splenomegaly, and respiratory disturbances.
SYN: SEE: Fort Bragg fever

puerperal fever

SEE: Puerperal sepsis.

Q fever

1. An acute infectious disease characterized by headache, fever, severe sweating, malaise, myalgia, and anorexia. Q fever is caused by the rickettsia, Coxiella burnetii, an intracellular, gram-negative bacterium, and is contracted by inhaling infected dust, drinking unpasteurized milk from infected animals, or handling infected animals such as goats, cows, or sheep. Transmission by human contact is rare but has occurred. An effective vaccine is available for the prevention of infection for those who have a good chance of being exposed to the disease. Tetracyclines are used to treat the infection.

SEROPREVALENCE
Although few people recall an episode of Q fever, antibodies against C. burnetti are found in more than 3% of the American population.

TREATMENT
Like other ricksettsial diseases, Q fever is treated with oral doxycycline.

2. A chronic infectious disease caused by the same organism (Coxiella burnetii), and characterized by endovascular infection, or endocarditis. Chronic Q fever has a high mortality rate.
SYN: SEE: Query fever

Query fever

SEE: Q fever.

rabbit fever

SEE: Tularemia.

rat-bite fever

Either of two infectious diseases transmitted by the bite of a rat. One is caused by Streptobacillus moniliformis and is marked by skin inflammation, fever, chills, headache, vomiting, and back and joint pain. The other is caused by Spirillum minus and is associated with ulceration, rash, and recurrent fever. The latter disease is rare in the U.S.
SYN: SEE: Haverhill fever; SEE: sodokosis; SEE: sodoku

TREATMENT
Both diseases are treated with penicillin. Therapy is most effective when penicillin is given intravenously for 1 week, then orally for 1 week. Tetanus prophylaxis is also administered.

relapsing fever

SEE: Borreliosis.

remittent fever

A pattern of fever that varies over a 24-hr period but does not return to normal.
SEE: malaria

rheumatic fever

ABBR: ARF A multisystem, febrile inflammatory disease that is a delayed complication of untreated group A streptococcal pharyngitis (strep throat).

INCIDENCE
The disease is primarily seen in children between the ages of 5 and 15, but it is now uncommon in Western societies because of effective and prompt treatment for strep throat. It remains a major cause of morbidity in the developing world.

CAUSES
It is believed to be caused by an autoimmune response to bacterial antigens in the streptococci although the precise mechanism responsible for the illness has not been identified.

SYMPTOMS AND SIGNS
After a pharyngeal infection with group A streptococci, some patients experience sudden fever and joint pain. Other symptoms include migratory joint pains, pain on motion, abdominal pain, chorea, and cardiac involvement (pericarditis, myocarditis, and endocarditis). Precordial discomfort and heart murmurs develop suddenly. Skin manifestations include erythema marginatum or circinatum and the development of subcutaneous nodules.

Rheumatic fever may occur without any sign or symptom of joint involvement.

DIAGNOSIS
The Jones criteria are used to diagnose acute rheumatic fever. Two major manifestations (carditis, polyarthritis, chorea, erythema marginatum, or subcutaneous nodules) or one major and two minor criteria (fever of at least 100.4°F [38°C], arthralgia, previous rheumatic fever, elevated erythrocyte sedimentation rate, positive C-reactive protein, or prolonged P-R interval) are required to establish the diagnosis of acute rheumatic fever. Titers of antistreptolysin, anti-DNase B, or both, are used to aid in disease confirmation, since they point to a recent infection with group A streptococcus. By the time patients develop symptoms of ARF, throat cultures for strep are usually negative. Antistreptococcal antibody titers rise during the first few weeks of the illness.

PROPHYLAXIS
Prompt and adequate treatment of streptococcal infections with oral penicillin or cephalosporin is given for at least 10 days. Erythromycin or sulfa drugs are substituted in patients with penicillin allergy.

To prevent recurrence of rheumatic fever in a patient who has already been affected by the disease, benzathine benzylpenicillin is given intramuscularly every 3 or 4 weeks. Low-dose oral penicillin, erythromycin, or sulfa drugs are alternatives for compliant patients.

TREATMENT
Penicillin is given during the acute phase of the illness, and periodically, e.g., monthly, thereafter to prevent a recurrence of the disease. Salicylates, acetaminophen, and NSAIDs are used to lower fever, reduce inflammation, and alleviate pain. Diuretics and other cardiac medications are prescribed as necessary to treat heart failure. Severe heart valve dysfunction requires surgical correction but usually not until late adolescence or adulthood. Patients known to have carditis who must undergo dental or surgical procedures, esp. those involving instrumentation of the urinary tract, rectum, or colon, should receive additional antibiotic coverage on the day of the procedure and for several days thereafter.

IMPACT ON HEALTH
Damage to heart valves (resulting in heart failure) is the most concerning complication of ARF.

PATIENT CARE
During the acute phase, diversional activities that are not physically demanding are offered; family and friends are encouraged to visit; and a tutor may be provided to help the child stay current with schoolwork. The child and family are taught about the disease and treatment, and all diagnostic measures are described. The child and family are also taught about signs of recurrent streptococcal infection and of heart failure, which require immediate reporting and treatment. Health care professionals advise the patient about lifestyle and activity modifications, as well as the importance of taking prescribed antibiotics for the full course of treatment and prophylaxis. The child and family are informed about symptoms of hypersensitivity reaction to the antibiotic and are advised to stop the drug immediately and to notify the primary care provider if a rash, fever, chills, or other signs of allergy develop anytime during the course of therapy. The importance of maintaining a salt-restricted diet and of adhering to treatment with diuretics, digoxin, or afterload-reducing drugs is emphasized for patients with congestive heart failure. The American Heart Association provides educational materials and current protocol for prevention of bacterial endocarditis, which is different from the rheumatic fever regimen used to prevent recurrence. (800-AHA-USA1; http://www.heart.org/HEARTORG/).

Rocky Mountain spotted fever

An infectious disease caused by Rickettsia ricketsii and transmitted by the wood tick Dermacentor andersoni or D. variabilis. It was originally thought to exist only in the western U.S., but it can occur anywhere that the tick vector is present.

SYMPTOMS AND SIGNS
The organism causes fever, headache, myalgia, and a characteristic vasculitic rash. The rash appears several days after the other symptoms, first erupting on the wrists and ankles, then on the palms and soles. It is nonpruritic and macular and spreads to the legs, arms, trunk, and face. Disseminated intravascular coagulation or pneumonia may be serious complications.

TREATMENT
Tetracyclines are the drug of choice for treating this disease but are not recommended for pregnant women. Chloramphenicol may be substituted.

PROGNOSIS
The mortality resulting from acute infection approaches 20%.

PATIENT CARE
People living in areas with wood ticks should wear clothing that covers much of their bodies, including the neck, to prevent ticks from attaching to the skin. People who live in or travel to areas where ticks flourish should examine their scalps, skin, and clothing daily. To remove ticks, grasp them close to their mouthparts and not on the tick's body, as close to their point of attachment to their human host as possible. Pets should be examined regularly for ticks.

rose fever

Hay fever of early summer attributed to inhaling rose pollen.
SEE: hay fever

sandfly fever

A mild viral disease that clinically resembles influenza. The causative organism is any of several species of Bunyaviridae viruses and is transmitted by the common sandfly Phlebotomus papatasi. The disease occurs in tropical and subtropical areas that have long periods of hot, dry weather. Several antiviral drugs, e.g., alpha interferon and ribavirin, have some effect against the disease.
SYN: SEE: pappataci fever; SEE: phlebotomus fever; SEE: three-day fever

San Joaquin valley fever

SEE: Coccidioidomycosis.

scarlet fever

An acute, contagious disease characterized by pharyngitis and a pimply red rash. It is caused by group A beta-hemolytic streptococcus and usually affects children between 3 and 15 years of age.
SYN: SEE: scarlatina; SEE: second disease

CAUSES
The disease is caused by more than 40 strains of group A, beta-hemolytic streptococci that elaborate an erythrogenic toxin.

SYMPTOMS AND SIGNS
After an incubation period of 1 to 7 days, children develop a fever, chills, vomiting, abdominal pain, and malaise. The pharynx and tonsils are swollen and red, and an exudate is present. Initially the tongue is white, with red, swollen papilla (white strawberry tongue); within 5 days, the white disappears, creating a red strawberry tongue. A red pinpoint rash that blanches on pressure with a sandpapery texture appears on the trunk (chest to neck, abdomen, legs and arms, sparing soles and palms) within 12 hr after the onset of fever. Cheeks are flushed, with pallor surrounding the mouth. Pastia lines (faint lines in the elbow creases) are characteristic findings in full-blown disease. Over several days, sloughing of the skin begins, which lasts approx. 3 weeks.

INCUBATION
The incubation period is probably never less than 24 hr. It may be 1 to 3 days, and rarely longer.

TREATMENT
Scarlet fever is treated with 10 days of penicillin (or erythromycin for those allergic to penicillin). A full course of therapy is vital to decrease the risk of rheumatic fever or glomerulonephritis. In general, patients are directed to isolate the infected child from siblings until they have received penicillin for 24 hr.

PATIENT CARE
Good hand hygiene techniques and proper disposal of tissues with purulent discharge are emphasized. The parents also are advised about the importance of administering the prescribed antibiotic as directed for the entire course of treatment even if the child looks and feels better. Because the child may be irritable and restless, the parents are taught how to encourage him or her to rest and relax. The child should be kept occupied with age-appropriate books, games, toys, and television.

Sennetsu fever

A form of ehrlichiosis first identified in Japan, transmitted to humans by tick bite or, possibly, consumption of infected raw fish, and caused by Ehrlichia sennetsu. Symptoms include fever, malaise, backache, and lymphadenopathy.

Shanghai fever

A diarrheal illness caused by Pseudomonas species, associated with high fever, a rose-colored spotted rash that resembles typhoid, and headache. The infection is usually contracted in the tropics.

snail fever

SEE: Schistosomiasis.

spotted fever

A general, imprecise name for a variety of infectious diseases (including typhus and rickettsial illnesses) characterized by fever and rash.
SEE: Rocky Mountain spotted fever

spring fever

A feeling of rejuvenation or increased sex drive that affects some people in the spring.

three-day fever

SEE: Sandfly fever.

tick-borne relapsing fever

Infection with species of Borrelia, transmitted to humans by arthropod bite. Symptoms include fever, headache, malaise, muscle pains, and vomiting, followed by periods of defervescence, and then recurrence of fevers. The disease is treated with doxycycline. It can be prevented by avoiding habitats where ticks propagate or by wearing insecticide-impregnated clothing when outdoors.

trench fever

A disease characterized by fever, headache, malaise, pain, tenderness (esp. in the shins), splenomegaly, and, often, a transient macular rash. The causative agent is Bartonella quintana. The disease is rarely encountered in industrialized nations, except among the homeless; it is prevalent in many developing nations. The disease is treated with doxycycline, 100 mg administered orally, twice a day.
SYN: SEE: Wolhynia fever

typhoid fever

A severe infectious disease marked by fever and septicemia, caused by Salmonella typhi. The CDC reports 5,700 cases per year in the U.S., mostly among travelers. An estimated 21 million cases of typhoid fever and 200,000 deaths occur worldwide because it is endemic in areas of poor sanitation.
SYN: SEE: enteric fever
SEE: typhoid vaccine

CAUSES
The Salmonella organism enters the gastroinestinal tract, infects the biliary tract, invades the lymphoid tissues and walls of the ileum and colon, seeds the intestinal tract with millions of bacilli, and then gains access to the bloodstream. The disease is most commonly transmitted via the fecal-oral route through water or food contaminated by human feces, but it can be spread by vomitus and oral secretions during the acute stage. Unlike S. enteritidis, it lives only in humans. A small percentage of people become carriers after recovering from infection.

SYMPTOMS AND SIGNS
GI symptoms may develop within 1 hr of ingestion of the bacillus, but they usually subside before the onset of the typhoid fever symptoms. The disease is marked initially by a gradually increasing fever up to 104°F (40°C), anorexia, malaise, myalgia, headache, and slow pulse for about 7 days, followed by remittent fever up to 104°F (40°C) that usually occurs in the evening: a flat, rose-colored, fleeting rash (primarily on the abdomen); chills and sweating; increasing abdominal pain and distention; diarrhea or constipation; generalized lymphadenopathy; abdominal pain; anorexia; weakness and exhaustion; cough and moist crackles; a tender abdomen with enlarged spleen; and delirium as the bacteria spread through the bloodstream. About 14 days after the infection begins, persistent fever and increased weakness and fatigue are present but usually subside by about 21 days into the illness although relapses may occur. Internal bleeding usually develops owing to GI ulcers, abscesses, and intestinal perforation; this may lead to hypovolemic shock. Damage to the liver and spleen is common. In approx. 10% of patients, typhoid fever is complicated by pneumonia, thrombophlebitis, osteomyelitis, septic arthritis, cerebral thrombosis, meningitis, myocarditis, or acute circulatory failure, which account for most of the deaths.

DIAGNOSIS
Paratyphoid fever, pneumonia, dysentery, meningitis, smallpox, and appendicitis are among the differential diagnoses. Diagnostic points of value are the presence of rose spots, splenomegaly, leukopenia, the Widal serological test result, blood culture, and examination of feces for the presence of the causative organism. The best means of providing bacterial confirmation is through bone marrow culture. This method is successful even after patients have received antibiotics.
SEE: paratyphoid fever

TREATMENT
The disease is treated with ciprofloxacin or other antimicrobials based on organism sensitivity testing for 10 days. Dexamethasone is administered a few minutes before antibiotics are given in patients with shock or decreased levels of consciousness. Travelers should be aware that the most important safeguards are good food handling and water sanitation. The CDC recommends vaccination with typhoid vaccine, which is available in a live attenuated oral and parenteral form and in an intramuscular form for people traveling to developing countries in Africa, Asia, the Indian subcontinent, Central and South America, and the Caribbean. The oral vaccine is taken in multiple doses, with adults and children over 6 prescribed one capsule every other day for a total of four doses. Each dose should be taken 1 hr before a meal with cool water, and the capsules kept in the refrigerator. The one-dose parenteral vaccine may be used as an option for children 2 to 6, for the immunocompromised, and for those who might not adhere to the oral regimen. Vaccination protects only 50% to 80% of those vaccinated; therefore, all travelers should protect themselves by following the adage, boil it, cook it, peel it, or forget it. The vaccinations should be completed at least 1 week before the trip; boosters are required every 2 to 5 years, depending on the type of vaccine. The vaccinations should not be given to patients who are taking mefloquine for malaria prophylaxis.

PATIENT CARE
Contact precautions (handwashing, patient handwashing, glove and gown for disposal of feces or fecally contaminated objects) are followed until three consecutive stool cultures at 24-hr intervals are negative. Drugs are administered as prescribed, and the patient is observed for signs of complications, e.g., bacteremia, intestinal bleeding, and bowel perforation. During the acute phase, the temperature is monitored, but antipyretics are usually not administered because these mask the fever and can result in hypothermia; tepid sponge baths are also provided to promote vasodilation without shivering. The incontinent patient is cleansed, and high fluid intake (oral or intravenous) is encouraged to maintain adequate hydration. Fluid and electrolyte balance is monitored. Adequate nutrition is maintained. Rest is encouraged and oral hygiene and skin care provided. Abscesses may have to be drained surgically. The caregiver explains the importance of follow-up care and examination to ensure that the patient is not a carrier.

If the patient’s stool cultures are still positive at the time of discharge, he or she should be careful to use good hand hygiene, esp. after defecating, and should avoid preparation of uncooked foods, e.g., salads, for family members. Those who retain positive cultures (asymptomatic carrier state) should not be employed as food handlers. All cases of typhoid fever should be reported to the state health department. While traveling in endemic areas, people should be careful to buy bottled water or boil tap water for 5 min before drinking, cooking, or brushing their teeth with it; they should avoid ice in beverages, desserts, and treats; eat well-cooked foods that are still steaming hot; and avoid raw food, including garden or fruit salads. Before eating fresh fruit, people should wash their hands vigorously, wash the outside of the fruit, then peel the fruit, and they should avoid food sold by street vendors.

undulant fever

SEE: Brucellosis.

fever of unknown origin

ABBR: FUO An illness of at least 3 weeks' duration with fever exceeding 100.9°F (38.3°C) on several occasions and diagnosis not established after 1 week of hospital investigation. The main causes are systemic and localized infections, neoplasms, or collagen-vascular diseases, e.g., rheumatoid arthritis, disseminated lupus erythematosus, and polyarteritis nodosa. Less common causes are granulomatous disease, inflammatory disease of the bowel, pulmonary embolization, drug fever, cirrhosis, and rare conditions such as Whipple disease. Diseases such as AIDS, chronic fatigue syndrome, or Lyme disease are occasionally the cause of FUO. Some cases remain undiagnosed.

valley fever

SEE: Coccidioidomycosis.

viral hemorrhagic fever

ABBR: VHF Any of a group of diseases caused by arthropod-borne viruses, esp. the Bunyaviridae group, including Alkhurma, Congo-Crimean, Ebola, Lassa, Marburg, and Rift Valley hemorrhagic fever viruses.

Wolhynia fever

SEE: Trench fever.

yellow fever

Either of two forms of an acute, infectious disease caused by a flavivirus and transmitted by species of the Aedes mosquito. It is endemic in Western Africa, Brazil, and the Amazon region of South America but is no longer present in the U.S.
There are two forms of yellow fever: urban, in which the transmission cycle is mosquito to human to mosquito; and sylvan, in which the reservoir is wild primates.

According to the World Health Organization, yellow fever afflicts about 200,000 people a year in Africa and South America, about 30,000 of whom die.

CAUSES
The virus is carried most commonly by the Aedes aegypti mosquito, but the A. vittatus and A. taylori mosquitoes are also important vectors.

SYMPTOMS AND SIGNS
After an incubation period of 3 to 6 days, patients develop high fever, headache, muscle aches, nausea and vomiting, and GI disturbances such as diarrhea or constipation. In most patients, the disease resolves in 2 or 3 days, but in about 20% the fever returns after a 1- to 2-day remission and is accompanied by abdominal pain, severe diarrhea, GI bleeding (producing a characteristic black vomit), anuria, and jaundice (hence the name yellow fever) caused by liver infection. Rarely, there is progressive liver failure, renal failure, and death.

Yellow fever can be distinguished from dengue by the presence of jaundice, and from malaria by the absence of splenomegaly and low serum transaminase levels. Blood tests can identify the virus and its antigens, to which antibodies are formed in 5 to 7 days. A liver biopsy to isolate the virus is contraindicated because of the risk of bleeding.

LABORATORY FINDINGS
As in many viral infections, the white blood cell count and platelet count may be suppressed. The erythrocyte sedimentation rate is rarely elevated. In severely ill patients with jaundice or renal failure, the serum bilirubin and creatinine levels are elevated.

DIAGNOSIS
Diagnosis on clinical grounds alone is almost impossible during the period of infection or in atypical mild forms. Yellow fever viral antigen or antibodies may be detected during the acute phase of the illness.

PROPHYLAXIS
Preventive measures include mosquito control by screening, spraying with nontoxic insecticides, and destruction of breeding areas. Yellow fever vaccine prepared from the 17D strain is available for those who plan to travel or live in areas where the disease is endemic. The vaccine is contraindicated in infants under 4 months old and in women in the first trimester of pregnancy.

TREATMENT
No antiviral agents are effective against the yellow fever virus. Fluids are given to maintain fluid and electrolyte balance, acetaminophen to reduce fever, and histamine blockers, e.g., ranitidine, or gastric acid pump inhibitors, e.g., omeprazole, to decrease the risk of GI bleeding. Vitamin K is given if there is decreased production of prothrombin by the liver.

A live virus vaccine, which can be obtained only at designated vaccination centers, may be given to adults and children over 9 months old who are traveling to countries where yellow fever is endemic; the vaccine is effective for 10 years, after which a booster is required. Those who are immunosuppressed, pregnant, or allergic to eggs should not receive the vaccine. Travelers must determine if the country they are visiting has regulations about vaccination.

IMPACT ON HEALTH
The prognosis is grave. Mortality is 5% in an area where the disease is endemic.