What are childhood infectious diseases?
Acute communicable diseases occur primarily in childhood because most adults have become immune to such diseases, either by having acquired them as children or by having been inoculated against them. For example, prior to the use of vaccine for measles—a highly contagious disease found in most of the world—the peak incidence of the disease was in five- to ten-year-olds. Most adults were immune. Before a vaccine was developed and used against measles, epidemics occurred at two- to four-year intervals in large cities. Today, most cases are found in nonimmunized preschool children or in teenagers or young adults who have received only one dose of the vaccine.
Measles, a highly contagious virus, is a leading cause of fatalities among children worldwide. A person infected with red measles (also known as rubeola) becomes contagious about ten days after exposure to the disease virus, at which time the prodromal stage begins. Typically, the infected person experiences three days of slight to moderate fever, a runny nose, increasing cough, and conjunctivitis. During the prodromal stage, Koplik’s spots appear inside the cheeks opposite the lower molars. These lesions—grayish white dots about the size of sand particles with a slightly reddish halo surrounding them that are occasionally hemorrhagic—are important in the diagnosis of measles.
After the prodrome, a rash appears, usually accompanied by an abrupt increase in temperature (sometimes as high as 104 or 105 degrees Fahrenheit). It begins in the form of small, faintly red spots and progresses to large, dusky red confluent areas, often slightly hemorrhagic. The rash frequently begins behind the ears but spreads rapidly over the entire face, neck, upper arms, and upper part of the chest within the first twenty-four hours. During the next twenty-four hours, it spreads over the back, abdomen, entire arms, and thighs. When it finally reaches the feet after the second or third day of the rash, it is already fading from the face. At this point, the fever is usually disappearing as well.
The chief complications of measles are middle-ear infections, pneumonia, and encephalitis (a severe infection of the brain). There is no correlation between the severity of the case of measles and the development of encephalitis, but the incidence of the infection of the brain runs to only one or two per every thousand cases. Measles can also exacerbate tuberculosis.
The incubation period for rubella (German measles) lasts between fourteen and twenty-one days, and the disease occurs primarily in children between the ages of two and ten. Like the initial rash of measles, the initial rash of rubella usually starts behind the ears, but children with rubella normally have no symptoms save for the rash and a low-grade fever for one day. Adolescents may have a three-day prodromal period of malaise, runny nose, and mild conjunctivitis; adolescent girls may have arthritis in several joints that lasts for weeks. The red spots begin behind the ears and then spread to the face, neck, trunk, and extremities. This rash may coalesce and last up to five days. Temperature may be normal or slightly elevated. Complications from rubella are relatively uncommon, but if pregnant women are not immune to the disease and are exposed to the rubella virus during early pregnancy, severe congenital anomalies may result. Because similar symptoms and rashes develop in many viral diseases, rubella is difficult to diagnose clinically. Except in known epidemics, laboratory confirmation is often necessary.
The patient with mumps is likely to have fever, malaise, headache, and anorexia—all usually mild—but “neck swelling,” a painful enlargement of the parotid gland near the ear, is the sign that often brings the child to a doctor. Maximum swelling peaks after one to three days and begins in one or both parotid glands, but it may involve other salivary glands. The swelling pushes the earlobe upward and outward and obscures the angle of the mandible. Drinking sour liquids such as lemon juice may increase the pain. The opening of the duct inside the cheek from the affected parotid gland may appear red and swollen.
The painful swelling usually dissipates by seven days. Abdominal pain may be caused by pancreatitis, a common complication but one that is usually mild. The most feared complication, sterility, is not as common as most believe. Orchitis rarely occurs in prepubertal boys and occurs in only 20 to 30 percent of older males. In 35 percent of patients with orchitis, both testes are involved, and a similar percentage of affected testes will atrophy. Surprisingly, impairment of fertility in males is only about 13 percent; absolute infertility is rare. Ovary involvement in women, with pelvic pain and tenderness, occurs in only about 7 percent of postpubertal women and with no evidence of impaired fertility. Mumps during early pregnancy may cause miscarriage, but this is a rare complication for females who have been immunized.
Hemophilus influenzae type B is the most common cause of serious bacterial infection in the young child. It is the leading cause of bacterial meningitis in children between the ages of one month and four years, and it is the cause of many other serious, life-threatening bacterial infections in the young child. Bacterial meningitis, especially from Hemophilus influenzae and pneumococcus, is the major cause of acquired hearing impairment in childhood.
Poliomyelitis (polio), an acute viral infection, has a wide range of manifestations. The minor illness pattern accounts for 80 to 90 percent of clinical infections in children. Symptoms, usually mild in this form, include slight fever, malaise, headache, sore throat, and vomiting but do not involve the central nervous system. Major illness occurs primarily in older children and adults. It may begin with fever, severe headache, stiff neck and back, deep muscle pain, and abnormal sensations, such as of burning, prickling, tickling, or tingling. These symptoms of aseptic meningitis may go no further or may progress to the loss of tendon reflexes and asymmetric weakness or paralysis of muscle groups. Fewer than 25 percent of paralytic polio patients suffer permanent disability. Most return in muscle function occurs within six months, but improvement may continue for two years. Twenty-five percent of paralytic patients have mild residual symptoms, and 50 percent recover completely. A long-term study of adults who suffered the disease has documented slowly progressive muscle weakness, especially in patients who experienced severe disabilities initially.
Tetanus is a bacterial disease which, once established in a wound of a patient without significant immunity, will build a substance that acts at the neuromuscular junction, the spinal cord, and the brain. Clinically, the patient experiences “lockjaw,” a tetanic spasm causing the spine and extremities to bend with convexity forward; spasms of the facial muscles cause the famous “sardonic smile.” Minimal stimulation of any muscle group may cause painful spasms.
Diphtheria is another bacterial disease that produces a virulent substance, but this one attacks heart muscle and nervous tissue. There is a severe mucopurulent discharge from the nose and an exudative pharyngitis (a sore throat accompanied by phlegm) with the formation of a pseudomembrane. Swelling just below the back of the throat may lead to stridor (noisy, high-pitched breathing) and to the dark bluish or purplish coloration of the skin and mucous membranes because of decreased oxygenation of the blood. The result may be heart failure and damaged nerves; respiratory insufficiency may be caused by diaphragmatic paralysis.
Clinically, pertussis (whooping cough) can be divided into three stages, each lasting about two weeks. Initial symptoms resembling the common cold are followed by the characteristic paroxysmal cough and then convalescence. In the middle stage, multiple, rapid coughs, which may last more than a minute, will be followed by a sudden inspiration of air and a characteristic “whoop.” In the final stage, vomiting commonly follows coughing attacks. Almost any stimulus precipitates an attack. Seizures may occur as a result of hypoxia (inadequate oxygen supply) or brain damage. Pneumonia can develop, and even death may occur when the illness is severe.
Varicella (chickenpox) produces a generalized itchy, blister-like rash with low-grade fever and few other symptoms. Minor complications, such as ear infections, occasionally occur, as does pneumonia, but serious complications such as infection in the brain are rare. It is a very inconvenient disease, however, requiring the infected person to be quarantined for about nine days or until the skin lesions have dried up completely. Varicella, a herpes family virus, may lie dormant in nerve linings for years and suddenly emerge in the linear-grouped skin lesions identified as herpes zoster. These painful skin lesions follow the distribution of the affected nerve. Herpes zoster is commonly known as shingles.
Hepatitis type B is much more common in adults than in children, except in certain immigrant populations in which hepatitis B viral infections are endemic. High carrier rates appear in certain Asian and Pacific Islander groups and among some Inuits in Alaska, in whom perinatal transmission is the most common means of perpetuating the disease. Having this disease in childhood can cause problems later in life. An estimated five thousand deaths in the United States per year from cirrhosis or liver cancer occur as a result of hepatitis B. Carrier rates of between 5 and 10 percent result from disease acquired after the age of five, but between 80 and 90 percent will be carriers if they are infected at birth. The serious problems of hepatitis B occur most often in chronic carriers. For example, approximately, 15 to 40 percent of carriers will ultimately develop liver cancer. The virus is fifty to one hundred times more infectious than Human immunodeficiency virus (HIV), the virus that causes Acquired immunodeficiency syndrome (AIDS). Health care workers are at high risk of contracting hepatitis B, but virtually everyone is at risk for contracting this disease because it is so contagious.
Hepatitis type A is a virus that causes jaundice, fatigue, abdominal pain, nausea, diarrhea, and fever. Approximately 15 percent of those who have the disease will have relapsing symptoms for six to nine months. Hepatitis A is usually spread through fecal contamination, and during epidemic years over 35,000 cases are diagnosed in the United States.
The Centers for Disease Control and Prevention (CDC) and the US Department of Health and Human Services recommend immunizing all infants soon after birth and again at age one to two months, with a final dose after the age of twenty-four weeks. The Committee on Infectious Diseases of the American Academy of Pediatrics recommends extending hepatitis B immunization to all adolescents, if possible. Based on field trials, the hepatitis B vaccine appears to be between 80 and 90 percent effective. The plasma-derived vaccine is protective against chronic hepatitis B infection for at least nine years. Newer, yeast-derived vaccines appear to be safe for administration to all, including pregnant women and infants: Both the vaccine and a placebo evoke the same incidence of adverse reactions. These yeast-derived vaccines will be monitored to see if a booster dose is needed.
The incidence of infection with hepatitis B increases rapidly in adolescence, but teenagers are less likely to comply with immunization than are infants. Asking adolescents to participate in a three-dose immunization program over a six-month period is likely to result in high dropout rates. Therefore, the American Academy of Pediatrics has recommended combining vaccination at birth with vaccination of teenagers. Two states, Alaska and Hawaii, have implemented universal immunization of infants with hepatitis B vaccine, and so have twenty nations. Thirty-four states require vaccination for students before entry to middle school. Hepatitis A vaccine is recommended by the CDC for all children between twelve and twenty-three months of age. Two doses of the vaccine should be given, at least six months apart.
Primary vaccination with DTaP (diphtheria, tetanus, and acellular pertussis) vaccine is recommended at two months, four months, and six months of age, followed by boosters at fifteen to eighteen months and upon entry into school (at four to six years of age).
Once a child reaches fifteen months of age, only one dose of the Hemophilus influenzae type B vaccine is necessary, but vaccination should begin at two months of age. Three vaccines are licensed for use in infants. Depending upon which vaccine is used, shots are given at ages two, four, and six months, with a booster between twelve and fifteen months. These vaccines are safe and at least 90 percent effective in preventing serious illness, such as sepsis and meningitis, from influenza B.
At two and four months of age, infants should receive an inactivated poliovirus vaccination, with boosters between six and eighteen months and upon entry into school (four to six years of age).
MMR (measles, mumps, rubella) vaccination should take place at twelve and fifteen months and at four to six years of age. If the infant lives in a high-risk area, the first dose should occur at twelve months of age. While women who are pregnant or plan to become pregnant in the next three months should not receive MMR vaccination, children may receive the vaccine even if the mother is pregnant, since the viruses are not shed by immunized individuals. Children who have not received the second dose should be vaccinated at eleven to twelve years.
In the 1990s, researchers announced that they had developed a vaccine to prevent chickenpox. According to the CDC, the first dose of varicella vaccine should be given to children between twelve and fifteen months of age who have not had chickenpox. The second dose is given between ages four and six, but may be given as soon as three months after the first dose. Individuals age thirteen and older who have never had chickenpox or the vaccine should get two doses given at least twenty-eight days apart. The chickenpox vaccine is contraindicated for those who have had life-threatening allergic reactions to a prior dose of the vaccine, gelatin, or neomycin; children who are taking aspirin or other salicylates should not be given the vaccine. Those who are ill at the scheduled vaccination time and pregnant women should wait before being vaccinated. Those who have immune system diseases, are taking drugs that affect the immune system, have cancer, are receiving cancer treatments, or have had a recent blood transfusion or other blood products should check with their health care provider before receiving the vaccine.
The CDC states that a combination vaccine called MMRV containing both chickenpox and MMR vaccines can be given instead of the two individual vaccines to children twelve and under. The combination vaccine is associated with rash and higher rates of fever than the two vaccines administered separately; seizures caused by a fever are also more frequently reported with the combination vaccine.
Influenza vaccine, containing two strains of type A and one strain of type B, is now recommended to be administered to all children to prevent infection with seasonal influenza viruses. Annual vaccination is necessary as influenza viruses continually mutate, resulting in new strains not present in previous vaccines. Sometimes, special strains of influenza, such as H1N1 (swine) influenza, may necessitate adding a separate influenza vaccine. Vaccination is particularly important for children with chronic heart and lung disease, diabetes, HIV, sickle cell disease, and other chronic conditions that place them at greater risk for severe influenza.
Pneumococcal vaccine is now routinely given to children aged two to twenty-three months and to certain children aged twenty-four to fifty-nine months who are at risk of overwhelming pneumococcal infections. For example, children without spleens and children with sickle cell disease should be considered for vaccination against pneumococcal disease.
Meningococcal vaccine, which protects against bacteremia and meningitis caused by some strains of meningococci, should be given to children with certain immune deficiency states, including the absence of a functioning spleen. The vaccine may also be given if there is an outbreak of meningococcal disease caused by a strain included in the vaccine, or if the child is traveling to a part of the world where the disease is common.
Some parents refuse to have their children vaccinated against pertussis because of concerns about the vaccine’s safety. Media focus on the safety of pertussis vaccines, as well as lawsuits, has frightened many physicians as well, the result being that they may be overly cautious in interpreting vaccine contraindications. Yet primary care physicians have also been sued for failing to give timely immunizations, which may result in complications from preventable disease. The Tennessee Medicaid Pertussis Vaccine Data should reassure them of the vaccine’s safety. Other pertussis vaccine safety information is also available, including reports from the American Academy of Pediatrics Task Force on Pertussis and Pertussis Immunization. Some parents have feared that there is a link between vaccinations and neurological disorders such as autism, but studies have found no connection.
The means exist to prevent many serious illnesses from infectious diseases in childhood, but both parents and health care professionals must make the effort to vaccinate all children at the appropriate times in their lives.
Some vaccines are more protective than others; effectiveness may hinge on a number of factors. In 1989, for example, 40 percent of people who developed measles had been vaccinated correctly under the old guidelines of one dose. Recommendations were therefore revised to include a booster dose. In the case of the hepatitis B vaccine, initial recommendations for administration of the vaccine established no injection site (only intramuscular), but studies revealed that there were fewer vaccine failures in recipients who were vaccinated in the deltoid region of the arm as opposed to the buttocks. The recommendation for injection site was therefore revised.
In the United States, vaccine coverage increased by the late 1990s after having been woefully inadequate during the 1980s. One state’s department of health, in a 1987 study, discovered that only 64 percent of children who were two years old were adequately vaccinated with DTaP, oral polio, and MMR vaccines. Although by 2000, rates were closer to 80 percent, in 2011, the rates had only moved to 82 percent. Undoubtedly, multiple and interacting factors have inhibited full vaccine coverage for all American children, including physicians’ attitudes and practice behaviors. For parents, the cost of vaccination, lack of health insurance, and other barriers to health care frustrate their efforts to get their children immunized. Some parents, for ideological or other reasons, may even be disinterested in or opposed to vaccination. In today’s highly mobile society, however, all persons should keep a standard personal immunization record to facilitate immunization coverage.
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