Introduction, history of reportable diseases
Definitions of Classes
Brief summary of each disease
The reason behind making certain diseases reportable is
ultimately to protect the public.
Keeping an accurate surveillance system of infectious disease protects
the public by preventing the spread of disease and perhaps eliminating the
disease entirely. Lists of reportable
diseases vary slightly from state to state.
The differences lie in whether lesser known diseases that are not
nationally reported are reported on a state level. This summary will focus on
reporting of disease began in this country in 1874 when the State Board of
Health of Massachusetts instituted
weekly voluntary reporting of prevalent diseases by physicians. In 1883,
step in disease reporting is identification of a suspected case. This is done by a health care provider of
some sort. The case is reported to the
local health department and then on to the state and national level if
necessary. Summaries of reported disease
of the reportable disease statistics in
National statistics are published weekly in the CDC’s Morbidity and Mortality Weekly Report. There are over 50 diseases and related conditions published in this report. These cases are put together and published on a yearly basis in the CDC’s “Summary of Notifiable Diseases”. The following tables are adopted from this publication in 2003, summarizing disease incidence in 2001. Some helpful websites in accessing national reporting systems are:
National center for infectious disease: infectious disease surveillance
This site offers information about different surveillance systems as well as links to reports from these different systems.
Morbidity and Mortality Weekly report
This site publishes weekly updates about notifiable diseases as well as extensive yearly summaries.
Reporting of notifiable diseases on an international scale is described in the International Health Regulations (IHR) put out by the World Health Organization. The IHR originially were set up to monitor 6 major infections: cholera, plague, yellow fever, smallpox, relapsing fever, and typhus. Today the IHR’s list of notifiable diseases are yellow fever, plague, and cholera. The organization responsible for overseeing the reporting of diseases is the Global Outbreak Alert and Response Network (GOARN). Global epidemic intelligence focuses on communicable diseases such as hemorrhagic fevers, cholera, meningitis, salmonellosis, and encephalitis as well as food and water safety. GOARN is a collaboration of over 100 institutions and NGOs set up to rapidly respond to disease outbreaks around the world.
Outbreak information is made available weekly in the WHO Outbreak Verification List. Another source for worldwide statistics is the Weekly Epidemiological Record (WER) that provides information mainly on diseases under the IHR.
And excellent resource to find out more about international disease reporting is the WHO’s site on Communicable Disease Surveillance and Response:
Definitions of classes
Reportable diseases in
also be noted that cases of human immunodeficiency virus (HIV) are reported on
separate forms from other diseases.
HIV/AIDS is not classified in any of the listed categories and has an
entirely separate system of reporting, at least in
Brief Summaries of
Diseases Reportable in
Class A1 diseases
Anthrax is caused by Bacillus anthracis and is most common among wild and domestic animals such as cattle, sheep, and goats. It is most common in agricultural regions, and human cases are usually from occupational exposure. It is a potential agent for biological warfare so the Department of Defense vaccinates active military personnel. Anthrax occurs in three forms: cutaneous (skin), inhalation, and gastrointestinal. The spores can survive in the soil or animal hides for years. It can also be acquired by eating undercooked meat from infected animals. Most anthrax cases are the cutaneous form when the bacteria enters a preexisting skin wound. It then forms a characteristic black ulcer. Untreated, this form has a 20% mortality. Inhalation anthrax is similar to a cold, but then progresses to great difficulty breathing resulting in shock and usually death. Intestinal anthrax causes severe gastrointestinal symptoms including vomiting blood, and is fatal in 25-60% of cases. Treatment is with penicillin G. Spread of anthrax from person to person is highly unlikely.
Botulism (from food)
Botulism is a paralyzing illness caused by the bacteria Clostridium
botulinum. 25% of botulism cases in
Cholera is an intestinal illness caused by the bacteria Vibrio cholerae. Infections can be mild or severe. 5% of people have severe disease with profuse watery diarrhea, vomiting, and cramping. The loss of body fluids can very rapidly lead to dehydration, shock, and death. Cholera is spread by the fecal-oral route most commonly through contaminated drinking water or food. Occasionally, cholera is contracted from eating raw shellfish. The disease rarely spreads from person to person. Symptoms usually start 2-3 days after exposure. Treatment includes mainly fluid resuscitation either orally or intravenously. There is a vaccine for cholera, but it only provides brief and incomplete immunity. Prevention includes boiling drinking water in at risk areas and proper hygiene.
Diphtheria is caused by the bacterium Corynebacterium diphtheriae. It causes upper respiratory infection with nasal discharge, sore throat, fever, and the formation of a whitish membrane on the tonsils, nasal septum, and pharynx. This may progress to hoarseness and cough with obstruction of the airway. Diagnosis is with culture of the organism, but clinical diagnosis is enough to start therapy. Most cases are in unimmunized children. It is passed through the air, usually by coughing. Treatment includes antitoxin along with antibiotics, usually penicillin and erythromycin. Having disease does not necessarily confer immunity, so patients should be immunized following resolution of the disease. Patients with diphtheria must be isolated while contagious. Contacts of the case must be cultured and boosters given.
Measles is a highly contagious viral disease that has been largely controlled through immunization. It is spread through nasal and mouth secretions and occasionally through the air. Symptoms appear in 2 stages: 1) runny nose, cough, and fever, possibly red eyes and photosensitivity, and 2) higher fever and red rash beginning on the face, then spreading over the body. White spots known as Koplik spots may appear inside the mouth. Complications include pneumonia, which is usually the cause of death in fatal cases. There is no specific treatment. Vaccination or having the disease confers permanent immunity.
Meningococcal disease includes meningitis and meningococcemia (disseminated infection in the blood) by the bacteria Neisseria meningitides. Many people carry the bacteria and are asymptomatic. It is passed by droplets. Symptoms of meningitis include altered mental status, stiff neck, photophobia, fever, and possibly seizures. Symptoms of meningococcemia are acute onset of fever/chills, malaise, and rash of pink or purple bumps. It can quickly progress to blood clotting abnormalities, shock, coma, and death. Diagnosis of both illnesses is made by Gram stain of spinal fluid or culture of the blood or spinal fluid. Treatment requires hospitalization and intravenous antibiotics. Patients should be isolated until they have received 24 hours of antibiotics. High risk contacts of cases should receive rifampin. There is a vaccine available but only to control outbreaks. It is not recommended for the general population.
Plague, known as the Black Death in the middle ages, is
caused by the bacteria Yersinia pestis and is carried by fleas on
rodents. Risk factors include working or
living in areas of infected rodents. In
The rabies virus is transmitted from infected animals and affects the central nervous system. It is fatal once symptoms occur. Transmission is usually from a bite of a rabid animal. Early symptoms are irritability, headache, anxiety, and fever. These progress to paralysis, muscle spasms, seizures, delirium, and death. Patients often have an intense fear of water. Rabies can be prevented by immediate wound cleansing, the administration of rabies immune globulin, and 5 doses of the rabies vaccine. Exposure from a rabid animal does not always result in disease. Prevention on a community scale is accomplished by minimizing the number of stray animals, and avoiding contact with wild animals.
Rubella (German measles) (not congenital)
Rubella virus is an airborne infection that causes German measles. The disease starts with a few days of fever, headache, malaise, conjunctivitis, runny nose, sore throat, cough, and swollen lymph nodes. These symptoms then disappear with the appearance of the characteristic rash. The rash consists of fine, pink bumps starting at the hair line and spreading downward. It lasts only 48 hours. The disease is especially dangerous in pregnant women since it can be devastating for the fetus. Diagnosis depends on antibody tests. There is no specific therapy. Patients should be isolated for 7 days after the onset of rash in order to protect susceptible pregnant women. The MMR vaccine has greatly reduced the incidence of rubella and is the best form of prevention.
Smallpox is caused by a virus known as Variola. It was declared eliminated in 1980 due to
worldwide vaccination, although stores of the virus are found in the
Several pathogens are responsible for causing hemorrhagic
fever. Some of the better known viruses
are Ebola virus, Lassa fever virus, and
This disease is caused by a virus transmitted by
mosquitoes. It is only found in
Chancroid is caused by the bacteria Haemophilus ducreyi. It is a sexually transmitted infection causing a painful genital ulcer and swollen inguinal lymph nodes. Several ulcers can develop. Humans are the only source. The organism can be isolated from the lesions. Treatment is with erythromycin. Its incidence has been steadily decreasing in industrialized countries.
This disease is caused by a one celled parasite, Cyclospora cayetanensis. It is passed by the fecal-oral route and can be found in contaminated water and food, usually fresh produce. It takes days to weeks for the parasite to become infectious once being passed in the stool, so person to person infection is unlikely. Symptoms include watery diarrhea, gas, cramping, vomiting, muscle aches, fever, and fatigue. Sometimes the symptoms relapse. Diagnosis is made by stool culture, but may take several samples. Treatment is fluid resuscitation and the antibiotic trimethoprim-sulfamethoxazole. Prevention includes hygienic food and water preparation.
Dengue is a disease caused by a
virus that is carried by infected Aedes mosquitoes. It occurs in most tropical and subtropical
areas of the world. Cases in the
E. coli 0157:H7
Most strains of E coli are harmless, but this one is particularly dangerous. E coli 0157:H7 produces a toxin that causes bloody diarrhea. Most outbreaks have been from contaminated beef. Infection can also come from drinking unpasteurized milk or contaminated water. It is passed by the fecal-oral route. Illness usually resolves in 5-7 days. In 2-7% of cases, infection leads to the complication of hemolytic uremic syndrome (see below). Diagnosis is by stool culture. Treatment is supportive and antibiotics may actually be counterproductive. Prevention includes eradicating this strain from the livestock population, and cooking meat thoroughly.
Most arboviruses (transmitted by mosquitoes) are asymptomatic or cause only mild disease. They peak during the warm months. They cause aseptic meningitis and/or encephalitis. Illness can manifest with a wide range of neurological symptoms. Diagnosis is by immunoassay of the CSF. Therapy is supportive. Eastern equine encephalitis (EEE) is an alphavirus. The reservoir of the virus is in birds. This is the rarest of the arboviral infections. EEE is fatal in about 30% of cases. There is a vaccine for horses, but it is ineffective in humans. After any case of EEE, bird and mosquito samples are taken in the area.
An outbreak is defined as “two or
more cases of a similar illness resulting from the ingestion of a common food”. An outbreak can be caused by a multitude of
different agents. Some common agents are
Staphylococcus aureus, Clostridium perfringens, Salmonella sp.,
This disease is caused by the bacteria Calymmatobacterium
granulomatis (which was previously known as Donovania granulomatis). The disease affects the lymph system near the
genital and anal area causing painless lumps under the skin that eventually
ulcerate and may join to form large ulcers.
It is common in tropical areas but rare in the
Invasive Haemophilus influenzae
This is usually caused by B type of this bacteria. ‘Invasive’ refers to the serious type of infection this bug can cause. In children it can cause meningitis, pneumonia, periorbital cellulites (infection around the eye), epiglottitis (infection and swelling in the lower throat), and septicemia (infection in the blood). The bacteria is spread through secretions. Treatment involves intravenous antibiotics. Infections of this type are not as common now since there is a vaccine against H. flu type B (the Hib vaccine). Those who are exposed to the bacteria can take rifampin to help prevent spread of the disease.
This is a group of viruses carried by rodents. Several varieties have been described, such
as Sin Nombre virus and
Hemolytic uremic syndrome
HUS is characterized by the sudden onset of a certain kind of anemia known as microangiopathic hemolytic anemia, kidney injury (possibly manifested by blood in the urine), and a low platelet count, which may cause easy bleeding and bruising. Most cases immediately follow a gastrointestinal illness such as that caused by E coli 0157:H7. Diagnosis is made by blood tests for the previous findings. Kidney failure may need to be treated by transfusion and dialysis.
Hepatitis A is a virus that causes disease in the liver. Many people do not have any symptoms when infected. Symptomatic people usually have sudden onset of fever, fatigue, nausea, dark urine, and jaundice (yellow skin and eyes). Symptoms persist for weeks to months. Diagnosis is made by an antibody test from the blood. Hep A is transmitted by the fecal-oral route. Treatment is supportive. There is a vaccine available for those at high risk.
This is an infection caused by the bacteria Legionella pneumophila. Sources of infection are usually water sources such as air conditioners and showers. Patients complain of fever/chills, cough, muscle aches, fatigue. A chest X-ray usually shows pneumonia. The kidneys may also be affected. The disease has a predilection for those with chronic lung disease and the immunocompromised. Diagnosis requires the use of specialized tests that are not widely available. Therapy is erythromycin and rifampin. Prevention is difficult.
This infection is caused by the bacteria Listeria monocytogenes, found in soil and water. It usually affects pregnant women, newborns, and immunocompromised adults. The bacteria has been found to contaminate many kinds of food (vegetables, cheese, meat, unpasteurized milk). Symptoms include fever, muscles aches, and gastrointestinal symptoms. The disease can progress to the nervous system causing headache, stiff neck, confusion, and seizures. Those infected during pregnancy often only have flu-like symptoms but the infection to the newborn is much more serious. There is no screening test for infection in pregnancy. Diagnosis is by culture of blood or spinal fluid. Several antibiotics are used for treatment, but the mortality rate is still significant. Those at risk are advised to thoroughly cook all food and to avoid soft cheeses.
This occurs in some cases of Chlamydia infection (see Class A3). It is characterized by genital lesions, swollen, infected regional lymph nodes, and hemorrhagic proctitis (rectal bleeding). It is usually sexually transmitted. Diagnosis is made by aspirating fluid from the lymph nodes and seeing inclusion bodies in leukocytes. Treatment is tetracycline.
Malaria is a disease caused by the one-celled parasite Plasmodium sp., and is passed by the bite of an Anopheles mosquito. It is mainly a disease of tropical areas. Symptoms include fever/chills, headache, GI upset, jaundice (yellow skin), and blood clotting abnormalities. More severe illness includes kidney or liver failure, infection in the brain (cerebral malaria) causing seizures, coma, and sometimes death. An untreated person’s blood may be infectious for weeks to years, depending on the Plasmodium species. Diagnosis is made by identifying the parasites on a blood smear. There are many treatments, most are quinine or sulfa based. There are also multiple drug options for prophylaxis for those traveling to or living in an endemic area.
Meningitis (aseptic, viral)
Aseptic meningitis is a catch-all term for any infectious or non-infectious meningitis where the cause is not identified by initial stains and cultures of spinal fluid. Most of these cases are caused by a virus such as coxcackie A or B, echovirus, herpes simplex, arboviruses, varicella, and adenovirus. Symptoms are the same as bacterial meningitis but may have a more insidious onset. Most people recover fully with purely supportive therapy. Spinal fluid can be tested for a multitude of viruses for diagnosis. Children with the disease are excluded from school until the fever has subsided. Prevention is good personal hygiene, especially those in child care.
Mumps is caused by a paramyxovirus passed in oral
secretions. It causes painful swelling
of any of the salivary glands, mainly the parotid, and fever. Other symptoms may occur such as loss of
appetite, abdominal pain, and headache.
Among males, 20% have accompanying orchitis (inflamed testicle). Complications of more severe disease include
pancreatitis, deafness, and meningitis.
Diagnosis is by recovering the virus from saliva, urine, or spinal
fluid. Treatment is supportive. In
Pertussis (Whooping cough)
Whooping cough is caused by the
bacteria Bordatella pertussis. It
has become rare due to the DTP and DTaP vaccines. The disease is airborne and is only found in
humans. Disease course is divided into 3
stages: 1) catarrhal, which resembles the common cold and lasts 1-2 weeks, 2)
paroxysmal, describing the violent coughing paroxysms that end in the
characteristic “whoop” inhalation and sometimes vomiting. This stage lasts 4-6 weeks. 3) convalescent, where the whoop and vomiting
stop and the cough begins to disappear over several weeks. Diagnosis is by isolating the organism or
through DNA tests. Treatment is only
effective if given during the catarrhal stage of the illness. The drug of choice is erythromycin. In
Polio is caused by poliovirus types 1, 2, and 3. It has been eradicated in the Western hemisphere due to the massive immunization campaign over the past few decades. Humans are the only source. Poliovirus is passed by the fecal-oral route and can be found in contaminated water sources such as swimming pools. Up to 90-95% of infections are asymptomatic, 4-8% of infections are mild and similar to a flu-like illness, 1-2% result in nonparalytic poliomyelitis characterized by aseptic meningitis, and only 0.1-2% of polio cases result in paralytic disease. Paralytic polio manifests as flaccid paralysis of one or more limbs with loss of reflexes but maintained sensation. In most cases, muscle function returns completely, but some cases have residual disability. Diagnosis is confirmed by isolating the virus in spinal fluid, stool, or oral secretions. Serologic tests are also available. There is no specific treatment. Immunization is the most important prevention.
This disease is caused by the bacteria Chlamydia psittaci and is transmitted to humans from birds like parrots, pigeons, and turkeys. Risk factors include owning or working with birds. Infection is usually from inhaling dust from bird feathers or bird secretions. Symptoms include fever/chills, headache, and occasionally pneumonia. Disease can be severe, even fatal, in immunocompromised hosts. Treatment is with tetracycline drugs. Prevention of human disease involves treating affected birds and abiding by quarantine laws in the import of birds.
Q fever (Query fever, Abattoir fever, Balkan grippe)
Q fever is caused by the bacteria Coxiella burnetii and is carried by dairy animals such as sheep and cattle. Risk factors include working on farms or meat packing plants, or drinking unpasteurized milk. Disease can be asymptomatic or present with flu-like illness that can lead to high fever, sore throat, cough, sweats, vomiting, diarrhea, and generalized pain. Chronic cases are similar to chronic fatigue syndrome. Diagnosis is made by antibody tests. Treatment is with tetracycline type drugs.
Rubella infection in a pregnant woman during the first trimester may have devastating effects on the fetus in utero and after delivery. The incidence of stillbirths and spontaneous abortions is increased. Infants born with rubella may have any of the following: cataracts or glaucoma, congenital heart defects, hearing loss, purpura (purple bruises), jaundice, a large spleen, a small head, mental retardation, meningitis, and bone disease. Diagnosis is by isolating the virus or by antibody tests. There is no therapy for the disease. Infants can remain infectious for up to a year and should be isolated for that long unless they have repeated negative cultures any time after 3 months of age.
Infection by any of the Salmonella species of bacteria is termed salmonellosis. The bacteria infect humans and animals, usually causing a diarrheal illness. It is passed by the fecal oral route or through ingesting infected animal products such as meat and dairy. It is also commonly carried by reptiles, so having pets such as lizards and turtles is a risk factor. It is a common cause of food poisoning. Illness usually consists of fever, abdominal cramps, and diarrhea 12-72 hours after consuming the infectious agent. Most people recover without treatment in less than a week. In some cases the infection spreads into the bloodstream, which can be fatal if untreated. Some patients later on develop painful joints, irritated eyes, and painful urination, known as Reiter’s syndrome. Diagnosis is by stool culture or by blood culture in invasive disease. Invasive disease can be treated with a multitude of antibiotics such as ampicillin and gentamycin. Prevention is through good hygiene and cooking food thoroughly.
This is caused by bacteria of the genus Shigella, the most common of which are Shigella sonnei, S flexneri, and S dysenteriae, which causes dysentery. It is passed by the fecal-oral route and is a common cause of food poisoning. Symptoms include diarrhea that is usually bloody, fever, and stomach cramps starting within 2 days of exposure. Children less than 2 years can also develop seizures with infection. Diagnosis depends on stool culture. Treatment is with a variety of antibiotics. Antidiarrheal agents generally make the illness worse. A small proportion of those infected with S flexneri will develop Reiter’s syndrome (painful joints and eyes, and painful urination). Prevention is good hygiene.
Resistant Staph aureus
The bacteria Staphylococcus aureus used to be highly susceptible to antibiotics such as penicillin and methcillin. Resistance has now developed to these and other drugs, posing a greater threat to those infected with the bacteria. Invasive infections with staph include septicemia (infection in the blood), osteomyelitis (infection in the bone), arthritis, endocarditis (infection of the heart valves), and pneumonia. Staph can also cause food poisoning and toxic shock syndrome (discussed elsewhere). The most well known resistant strain is methicillin resistant Staph aureus (MRSA), which requires treatment with vancomycin. A very few cases of vancomycin resistant disease (VRSA) have been described. The only drug shown to be affective against these cases is a new drug called linezolid. Patients with resistant disease must be isolated.
Syphilis is caused by the bacteria Treponema pallidum and is transmitted sexually. Disease is divided up into several stages. Primary syphilis is characterized by a painless chancre (ulcer type lesion) at the site of infection, usually the genitalia. Secondary syphilis usually manifests as a diffuse rash and swollen lymph nodes. Syphilis can present with a wide range of symptoms and is easily mistaken for other diseases. It used to be termed ‘the great imitator’. The disease can also remain latent for many years. Tertiary syphilis can present as neurosyphilis when the central nervous system is infected. Other manifestations of late syphilis are lesions in the heart, skin (known as gummas), and bone. A diagnosis can be made by several methods. The bacteria from the original lesion can be seen on darkfield microscopy or by antibody tests. Several blood tests for Treponema proteins or antibodies are available. Treatment is with penicillin G. All sexual contacts of cases should be referred for care. Prevention is safe sexual practices.
Tetanus is caused by the bacteria Clostridium tetani. Spores of the bacteria are found in the soil. They can then be introduced into a puncture wound. The bacteria do not need oxygen to grow. Symptoms include excitability and generalized muscle spasms particularly of the neck. Symptoms are due to a neurotoxin released by the bacteria. Diagnosis can be made by culture but is usually clinical. Treatment is with tetanus immune globulin or with an equine variety to counter the toxin. Penicillin G or tetracycline is also given to kill the bacteria. Prevention involves getting a booster tetanus shot every 10 years.
TB is caused by the bacteria Mycobacterium tuberculosis that is spread through the air. Many people are infected with TB, as seen by a positive PPD test on the skin but no bacteria in the sputum, but a far smaller number actually develop disease. Those with weakened immune systems are much more likely to develop active disease. Symptoms are fever, night sweats, weight loss, and cough. Diagnosis is made by seeing the bacteria on sputum smear and by characteristic lesions on chest X-ray. Several drugs are used to treat TB although resistance is developing. The most common drugs are isoniazid, rifampin, ethambutol, and streptomycin. Drugs must be taken for several months. Those with evidence of disease even if it is not active should take several months of isoniazid. Prevention involves using respiratory precautions among infected individuals.
Tularemia is caused by the bacteria Francisella tularensis and is found in a wide variety of animals as well as humans. It can be transmitted by handling tissues of infected animals, bites of deer flies or ticks, or eating undercooked meat of an infected animal. It cannot be spread person-to-person. The most common mode of transmission in this country involves rabbits. Those at risk are hunters and others who spend a lot of time outdoors or who handle wild animals. Symptoms start with a skin lesion and swollen lymph nodes. People may also have GI upset or a pneumonia-like illness. Treatment is with gentamycin. To prevent infection, gloves should be worn when handling animals like rabbits. Protective clothing outdoors is also recommended.
Typhoid is caused by the bacteria Salmonella typhi and occurs only in humans. It is passed by the fecal-oral route. Some people are carriers of the bacteria but do not suffer disease. Symptoms include a high fever, loss of appetite, abdominal pain, and rash. Severe cases can cause bowel obstruction. Diagnosis is by stool culture. Therapy includes ampicillin, trimethoprim-sulfamethoxazole, and ciprofloxacin. There is a vaccine available for those traveling to endemic countries. Prevention involves hygienic food preparation.
These outbreaks can be caused by many different kinds of organism. Some of the common causes are giardia, shigella, hepatitis A, and Norwalk-like viruses. The criteria for this kind of outbreak is 2 or more people must have similar illness after ingestion or exposure to the same water where the evidence points to water as the source of illness.
Amebiasis is an intestinal illness caused by Entamoeba histolytica, a parasite found worldwide. It is mainly found in tropical areas and unsanitary conditions. It is spread mainly by the fecal-oral route, so through contaminated food or water. It can be present for weeks to years, and can progress to amebic dysentery, which is characterized by abdominal pain, bloody stools, and fever. It can be cured with antibiotics.
Botulism (infant or wound)
Botulism is summarized above in Class A1. Wound botulism is seen most often among IV drug users. Medical care often involves surgical excision. Infant botulism is usually caused by the infant ingesting honey. Infants less than 1 year should not be fed honey. Infant botulism accounts for 72% of the cases of C botulinum infection.
Brucellosis (undulant fever)
Brucellosis is a bacterial disease, caused by Brucella species, usually spread by contact with livestock or products such as unpasteurized dairy products. It is not usually passed from person to person. Symptoms include fever/chills, headache, weakness, swollen lymph nodes, and weight loss. It is treated with doxycycline and streptomycin or rifampin. Early treatment can prevent chronic infection.
This is a disease of any bacteria in the Campylobacter
genus, usually C jejuni, and is the most common bacterial cause of
diarrhea in the
Chlamydia trachomatis causes many types of
infections. These include genital
infections of the urethra, epididymis, cervix, and fallopian tube, and
conjunctivitis and pneumonia in newborns.
It is the most prevalent of all STDs in the
CJD is a rare neurological disease usually found in older people. A new variant of CJD thought to be linked to bovine spongiform encephalopathy (BSE), commonly known as mad cow disease, afflicts younger people and from eating contaminated beef. Transmission is thought to occur through brain, eye, and spinal cord tissue of affected animals. The disease is thought to be caused by prions (protease resistant proteins) and not from an infectious etiology. Person to person transmission has not been seen. Symptoms include lethargy, decreased concentration, unsteadiness, agitation, dementia, and muscle spasms. Disease progresses to worsening dementia and ensuing death. There is not treatment.
This is a diarrheal disease caused by Cryptosporidum parvum, a one celled parasite. The eggs are shed in the stool and are the infectious agent. Risk includes drinking unfiltered water from rivers, lakes, or streams, and associating with infected persons. Illness is usually self-limited and includes watery diarrhea, fever, headache, and loss of appetite for 1-2 weeks. Immunocompromised individuals such as those with HIV or receiving chemotherapy can develop life-threatening illness from Cryptosporidium. Diagnosis is made from detecting the eggs in stool. Treatment is usually just supportive. Prevention includes proper cooking of food and good hygiene. Only bottled water that is distilled by reverse osmosis is considered free of the eggs.
Cytomegalovirus (CMV), also known as human (beta) herpesvirus 5, is a very common infection among adults, but can be devastating for a fetus. Intrauterine infection occurs in 0.5-2% of all births when the mother is infected during pregnancy, and is usually asymptomatic. Severe disease occurs in 5% of those infants infected in utero. Symptoms and signs include, lethargy, seizures, jaundice, petechiae, hepatosplenomegaly, intracerebral calcifications, and pulmonary edema. Infants that survive often have mental retardation, motor dysfunction, hearing loss, and liver disease. Diagnosis is made from viral culture or serology. It is usually transmitted in secretions such as saliva, urine, breast milk, and semen. The efficacy of antiviral therapy is debatable. Screening pregnant mothers for the virus has not been shown to be beneficial given the virus is shed intermittently, is extremely common, and lab tests are expensive. There is no vaccine.
This disease is caused by 2 species of Ehrlichia bacteria transmitted by ticks. People that spend a lot of time outdoors are at greatest risk. The disease caused by these bacteria are human monocytic ehrlichiosis (HME) caused by Ehrlichia chaffeensis, and human granulocytic ehrlichiosis (HE) cause by an unnamed Ehrlichia species. Symptoms include headache, fever/chills, aches, sweating, vomiting, and sometimes a rash. These occur 7-11 days after a tick bite. Diagnosis is by antibody assay. Treatment is tetracycline.
This is caused by the one celled parasite Giardia lamblia. It is passed by the fecal-oral route and is commonly contracted from contaminated water sources such as lakes and streams. Symptoms usually include diarrhea, nausea, and abdominal cramping, although many individuals are asymptomatic. Therapy is metronidazole. Prevention includes good hygiene, washing and peeling raw fruit and vegetables, and drinking bottled water when traveling. If a water source is suspected to be contaminated, it should first be checked for coliform bacteria since specific tests for Giardia are quite expensive.
Commonly known as gonorrhea, this is a sexually transmitted infection caused by the bacteria Neisseria gonorrheae. Patients may be asymptomatic or may experience pain on urination and/or a thick discharge. In women the disease can progress to pelvic inflammatory disease and cause pain in the lower abdomen. Untreated, PID can lead to infertility by scarring of the fallopian tubes. Diagnosis is made by culture or DNA based tests of the urethral or vaginal discharge. It can be treated with one injection of the antibiotic ceftriaxone, or with other drugs. All sexual contacts of the patient within the previous month should be tested and treated. Prevention involves safe sexual practices.
Hepatitis B virus affects the liver. Many cases resolve on their own, but some persist and cause lifelong infection, cirrhosis (scarring of the liver), liver cancer, all of which can lead to liver failure and death. Most people do not have acute disease when infected. Acute infections are similar to hepatitis A (see above). HBV is spread by blood and body fluids. Risk factors include unsafe sexual practices, IV drug abuse, and working with blood products. Diagnosis is made by antibody tests from the blood. There is no cure for hep B. There is a vaccine available that all children and adults at risk should receive. Prevention involves vaccination as well as safe sexual practices and not sharing needles.
Hepatitis C virus affects the liver and is spread by contact with an infected person’s blood. Risk factors include working with blood products, IV drug use, and having received blood transfusions. It is seldom transmitted sexually. HCV rarely manifests as an acute illness and most people are unaware they are infected. HCV is much more likely to cause long term liver damage than HBV. Of those infected, 70% develop chronic liver disease, 15% develop cirrhosis, and 5% die from complications of the infection. Diagnosis is by antibody tests. Treatment is with antiviral drugs such as interferon and ribavirin, although these drugs only provide a cure in 30-40% of patients.
Hepatitis D, Hepatitis E
These are other rare forms of hepatitis. Not much is known about them. Hep D exists conjointly with hep B and is spread the same way. Hep E is spread by the fecal-oral route. It resembles hep A and has a predilection for pregnant women.
Congenital herpes is caused by Herpes simplex virus types I and II, and manifests as several different symptom complexes: 1) disseminated disease involving the liver and other organs, 80% have skin lesions, 2) encephalitis, 60% have skin lesions, and 3) skin and mucosa involvement, 90% have skin lesions. The virus is isolted from skin lesions, mucous membranes, or spinal fluid. Transmission to the newborn usually occurs during the birthing process where the mother has active genital lesions. Thus, Caesarean section is recommended for these women. There is no cure for HSV. Infected infants should be placed in isolation and followed closely for a month.
This syndrome has no known etiology and is unresponsive to antibiotics. It consists of fever for more than 5 days, red eyes, redness around the lips and throat, swelling and redness of the extremities, rash, and large lymph nodes in the neck. Long term complications are coronary artery aneurysm with thrombosis. Diagnosis is purely clinical. It is most common in children less than 4 years of age. It cannot be transmitted person-to-person. Treatment consists of intravenous immune globulin and aspirin.
Leprosy (Hansen disease)
Leprosy is caused by the bacteria Mycobacterium leprae. It is a chronic infection that affects the
skin and nerves. There are several
manifestations of the disease: 1) tuberculoid, characterized by a few, light
colored, anesthetic lesions, 2) lepromatous, characterized by many red nodules
mainly on the face, hands, and feet in a symmetrical distribution, 3)
borderline, and 4) indeterminate.
Diagnosis is made from identifying the bacteria from skin biopsy. The disease is only found in humans. It is not very contagious, and usually is
spread by a lot of skin contact or by fomites (inanimate objects). The disease has a very long incubation
period: a person may not develop disease until many years after the
exposure. It is quite rare in the
This disease is caused by the bacteria of the genus Leptospira. It is found worldwide and is caused by ingesting water contaminated with an infected animal’s urine. Many kinds of animals carry the infection, and it is not passed from person-to-person. Infection can be asymptomatic or cause a multitude of symptoms such as fever/chills, headache, muscle aches, vomiting, diarrhea, jaundice, and rash. If left untreated, complications such as kidney or liver failure and meningitis can occur, usually in a relapse episode. Diagnosis is by blood or urine sample. Treatment is doxycycline or penicillin. Prevention involves avoiding possibly contaminated water sources such as lakes and streams.
Lyme disease is caused by the bacteria Borrelia
burgdorferi and is transmitted by the black-legged tick, Ixodes
scapularis. Risk factors include
being outdoors, especially in the summer/fall months and in wooded areas. The illness starts as a circular, red rash
around the tick bite that expands in size.
This is accompanied by flu-like symptoms and joint pain and
swelling. If untreated, nerve palsies
and heart problems can occur. Diagnosis
is by antibody tests in the blood or spinal fluid. Treatment is with tetracycline. Prevention includes wearing protective
clothing and insect repellant when outdoors in tall grass or wooded areas. When removing ticks from the body, it is
important to remove the mouthparts attached to the skin. Removed ticks can be checked for lyme disease
Meningitis (other bacterial)
Meningitis can be caused by a multitude of bacteria. The most dangerous and of greatest public health concern is that caused by Neisseria meningitides, as discussed above. Cases caused by other kinds of bacteria are also reportable. The most common of these are Streptococcus pneumoniae and Haemophilus influenzae type B. See the section on meningococcal disease for symptoms and treatment. Vaccines are available for H flu type B and for some strains of Strep pneumo.
Other mycobacterial disease
Other types of mycobacteria also cause disease. The most common is Mycobacterium avium intracellulare (MAI) which causes disease in immunocompromised patients such as those with AIDS. Disease is similar to MTB. It is treated with clarithromycin.
Pelvic inflammatory disease (PID)
PID is caused by several different organisms. The two most common are Neisseria gonorrheae and Chlamydia trachomatis. The disease results from the organisms spreading from the vagina to the pelvic organs (uterus, fallopian tubes). Criteria of PID are lower abdominal tenderness, cervical motion tenderness (pain on moving the cervix), and tenderness of the adnexa (ligaments surrounding the fallopian tubes). Additional signs of PID are high temperature, high white blood count, pus in the lower abdomen, and pelvic abscess. See gonococcal infection and chlamydia infection for diagnosis, treatment, and prevention.
The cause of Reye syndrome is not known. It usually follows a viral infection such as influenza or varicella (chicken pox). There is a link between taking aspirin during the viral illness and the development of Reye syndrome. The syndrome involves vomiting and encephalopathy presenting as an alteration in consciousness that can lead to coma and death. Liver damage is also present with increases in liver enzymes. It is a diagnosis of exclusion. Therapy is directed toward lowering intracranial pressure to decrease brain swelling. Prevention involves taking antipyretics other than aspirin during viral illnesses.
This is an inflammatory illness that sometimes occurs as a delayed reaction to inadequately treated group A streptococcal infection (strep throat). It is not communicable. Major criteria for disease are: carditis, polyarthritis (arthritis in several joints), chorea (uncoordinated movements), subcutaneous nodules, and a rash called erythema marginatum. Minor criteria that can be seen in rheumatic fever are: joint pain, fever, elevated erythrocyte sedimentation rate (ESR), positive C-reactive protein, or white count, and a prolonged PR interval (and EKG abnormality). Diagnosis is made clinically. Treatment is aimed at controlling inflammation and cardiac failure. This is usually done with aspirin and steroids. Some patients require prophylaxis with penicillin over the long term.
Rocky mountain spotted fever
This disease is caused by the bacteria Rickettsia rickettsii and is transmitted by the American dog tick, Dermacentor variabilis. Most cases are in the southern US. Symptoms start with headache, myalgias, and fever. A rash then develops, starting on the wrists and ankles spreading to the palms, soles, and trunk. Diagnosis is by antibody tests in the blood or DNA amplification. Treatment is tetracycline. Prevention includes controlling the tick population on dogs and wearing protective clothing outdoors.
Invasive Group A Strep
Group A Strep refers to Streptococcus pyogenes, bacteria commonly found in the mouth and on the skin. The bacteria become dangerous when they invade other areas of the body such as blood, lungs, spinal fluid, or muscle. People with chronic illness such as diabetes, lung, or heart problems are at greater risk of developing invasive disease. Diagnosis is with Gram stain and culture. Treatment is with penicillin based antibiotics and sometimes surgery.
Neonatal Group B Strep
Group B Streptococci are the most common cause of sepsis and meningitis in the newborn population. It is also a common cause of newborn pneumonia. One in 20 infected newborns die from the infection. The infection is usually acquired during childbirth from the mother’s birth canal since many women are asymptomatic carriers of the bacteria. Diagnosis is made by culture of blood or spinal fluid. Treatment is IV antibiotics of the penicillin family. Prevention includes culturing pregnant women at 35-37 weeks gestation. Infected women should be given intrapartem antibiotics to prevent infection of the newborn.
Invasive Streptococcus pneumoniae
This bacteria causes a multitude of infections: pneumonia, sepsis, ear infections, meningitis, peritonitis (infection in the abdominal cavity), and arthritis. Invasive disease has a 14% mortality rate. A vaccine (Pneumovax) has been developed that is effective against 89% of the serotypes causing invasive disease. It is not effective in infants.
Toxic shock syndrome
TSS can be caused by either group A Streptococci or Staph aureus. It can occur with any kind of infection but is usually associated with a skin lesion. In the past it has been associated with use of certain types of tampons. Disease is characterized by shock and multi-system organ failure. Early symptoms are high fever, rash, peeling skin on the palms and soles, and hypotension. Disease is toxin mediated and an organism is not usually found in the blood or spinal fluid. It is not communicable. Treatment consists of antibiotics as well as supportive therapy.
Mothers infected with Toxoplasma gondii early in pregnancy may pass the infection to the fetus. This can result in a variety of symptoms including encephalitis, chorioretinitis (inflammation of the retina), malformed organs, jaundice, and calcifications in the brain.
This disease is caused by the larvae of the nematode (type of worm) Trichinella spiralis. Many types of animals carry the parasite. Most human infections are from eating undercooked pork. Most cases are asymptomatic. Symptomatic cases manifest with gastroenteritis, eyelid swelling, muscle aches, fever/chills, and many eosinophils on a blood smear. The larvae enter through the digestive tract and then migrate to the muscles. Diagnosis is confirmed by a muscle biopsy or serologic tests. There is no treatment. Steroids may be helpful in severe cases. Disease is prevented by thoroughly cooking pork.
Typhus (murine typhus, squirrel associated epidemic typhus)
This disease is caused by either Rickettsia prowazekii or Rickettsia typhi transmitted by lice or fleas on mammals such as rats or flying squirrels. Symptoms include headache, fever, myalgias, and rash that starts on the trunk and spreads outward. Diagnosis is with serologic blood tests. Treatment is tetracycline. Prevention includes avoiding contact with squirrels.
Vancomycin resistant enterococcus
Enterococci are normal inhabitants of the gut. The drug vancomycin was developed to treat resistant strains of Staphylococcus. As a result, some strains of enterococcus have become resistant to vancomycin. Only some patients with VRE actually suffer disease from it. Patients at risk are those in intensive care settings and those who are immunocompromised. VRE is also frequently transmitted to health care workers who don’t use contact precautions in the hospital. The concern is that the vancomycin resistance gene will somehow find its way to Staphylococcus. This has been shown to happen in the laboratory, and a handful of cases have been described. The spread of VRE can be contained by improved infection control measures in healthcare facilities.
Varicella (deaths only)
Varicella is better known as chicken pox (discussed later). Only deaths due to varicella are classified as A3.
Two kinds of bacteria cause
disease in this category: Vibrio parahaemolyticus and Vibrio
vulnificus. V para causes a
self-limited gastrointestinal illness.
The bacteria is found in brackish waters in the
This disease is caused by bacteria from the genus Yersinia. It is spread by the fecal-oral route and is found among many domestic animals as well as humans. It causes gastrointestinal symptoms that are usually self limited. Diagnosis can be made by stool culture. Antibiotics are usually not used. Prevention includes good hygiene, especially after handling animals.
Class B diseases
Chicken pox are caused by varicella-zoster virus (VZV). Humans are the only host. Transmission is either airborne or through direct contact. It is usually a disease of children. Symptoms are a skin eruption of vesicles that are quite itchy. Fever and malaise may also be present. Complications include Reye syndrome, pneumonia, arthritis, and aseptic meningitis. Those infected as older children or adults are more likely to develop complications. Diagnosis can be made by isolating the virus from the lesions or by antibody tests. Treatment is symptomatic. Aspirin should not be used. Immunity is conferred after one infection. Cases should be isolated until the 6th day after the rash started or until all the lesions are dry. There is now a vaccine available.
Genital herpes is also caused by Herpes simplex virus types I and II and is transmitted sexually. The virus causes painful genital or anal ulcers. Primary infections may cause constitutional symptoms and painful lymph nodes. Diagnosis is made by isolating the virus from the lesion or showing the characteristic cell pattern (multinucleated giant cells) on a smear of the lesion. The antiviral drug acyclovir is given to control recurrences but is not curative. Prevention is safe sexual practices.
There are 3 influenza viruses: A, B, and C. It is spread through droplets from secretions. Cases can vary from asymptomatic to severe. Usually it causes a respiratory infection with fever/chills, headache, fatigue, and runny nose. Complications include pneumonia, myositis (muscle inflammation) and Reye syndrome (a post-viral encephalopathy). Diagnosis is through detection of viral antigen in the nose or through serological tests from the blood. Treatment is to alleviate symptoms. Aspirin should not be used since it increases the risk of developing Reye syndrome.
Class C diseases
This is caused by the fungus Blastomyces dermatitidis that is found in soil in much of the northeastern US. Infection occurs through the respiratory tract. It can cause a mild respiratory disease as well as granulomas in skin and bone. Diagnosis is by tissue biopsy. Treatment is with itraconazole or amphotericin B. There are no means of prevention.
Conjunctivitis is inflammation of the mucosa surrounding the eye, often resulting in irritation and discharge. It is commonly known as pink eye. It can be caused by a variety of organisms such as viruses, bacteria, fungi, or environmental allergens. Treatment depends on the causative agent.
Histoplasmosis (reticuloendothelial cytomycosis, cavern disease, Darling’s disease)
Histoplasma capsulatum is a fungus that grows in
the soil as well as animals and humans.
It is commonly found in caves or areas of bat and bird excreta, mainly
Nosocomial infections are infections acquired while a patient is admitted to the hospital or a healthcare facility. The rate of nosocomial infections can reflect an institution’s effectiveness at infection control. Common infections include pneumonia, urinary tract infections, and gastroenteritis.
There are several kinds of lice
that affect humans. Pediculus humanus capitis is the head louse, Pediculus
humanus corporis is the body louse, and Pthirus pubis is the pubic
or crab louse. Head lice cause itching
of the scalp and are found mainly among young school children. Head lice do not transmit diseases. Body lice are found only in populations with
very poor hygiene. They cause a rash of
itchy, red bumps in the affected area and have been known to transmit other
diseases such as typhus and relapsing fever.
Pubic lice or “crabs” infest coarsely haired parts of the body, and may
cause bluish lesions on the trunk and limbs.
They are usually spread by sexual contact and are not known to transmit
diseases. Diagnosis is made by finding
the nits or eggs in the hair. The
infected individual can be treated with one of several products: lindane
preparations, synergized natural pyrethrins, and synthetic pyrethrins. All contacts of the infested person should be
examined. The last step is to achieve
environmental control by cleaning all clothes, bedding, and other objects
contacted by the patient in the last 48 hours.
Scabies is a skin disease caused by mites that burrow into the skin. This causes itchy, pimple-like lesions and burrows, usually occurring in the finger web spaces, armpits, genitalia, and buttocks. The mites are transmitted from skin-to-skin contact or through infected clothing or bedding. Diagnosis is by microscopic analysis of skin scrapings. Treatment is with prescription creams containing lindane, permethrin, pyrethrin, or crotamiton. Infected clothing and bedding should be washed in hot water and/or sealed in a container for over a week. Fumigating the home is not necessary. Prevention involves wearing latex gloves whenever coming into contact with an infected person or their belongings.
Sporothrix schenckii is a fungus that lives on plants. When it enters the skin, usually from a thorn, it causes a pustule or ulcer and regional swollen lymph nodes. Diagnosis is from clinical history or tissue specimens. Treatment is itraconazole. It is commonly known as rose gardener’s disease. It can be prevented by wearing gloves while handling plants.
Staph skin infection
Staphylococcus aureus is a major cause of skin infections. These include furuncles (pimples and boils), impetigo (crusty lesions on the face), cellulitis, and wound infections. The bacteria is commonly found on the skin, and thus any break in the skin predisposes to infection. Diagnosis is by Gram stain or culture. Treatment is with a variety of antibiotics.
This disease is caused by the one-celled parasite, Toxoplasma gondii. Many people are infected, but most are asymptomatic. Illness develops mainly in those who are immunocompromised. Toxoplasmosis can be transmitted by any contact with cat feces, by eating infected meat, or by organ transplantation. Pregnant women who are newly infected with Toxoplasma can pass the infection to the fetus, which may result in mental retardation and other physical problems. Symptoms in adults usually resemble the flu. In the immunocompromised, toxo can cause serious damage to the eyes and brain. Several types of tests are available for diagnosis. Treatment is with antibiotics. Immunocompromised people and pregnant women should limit contact with cats to prevent infection.
Other outbreaks not categorized in A, B, or C.
Self-explanatory. Unrecognized diseases would fall into this category.
There are many, many diseases that are reportable in
Recommendations and Reports: Mandatory Reporting of
Infectious Diseases by Clinicians, Morbidity
and Mortality Weekly Report,
Centers for Disease
Control and Prevention. Summary of
foodborne-disease outbreaks –
“Surveillance for waterborne-disease outbreaks – US,
Levinson W, Jawetz E,
Medical Microbiology and Immunology 6th ed, Lange
Infectious Disease Control Manual (IDCM)
Summary of Infectious Diseases,
www.who.int/csr - Communicable Disease Surveillance and Response, WHO
National center for infectious disease: infectious disease surveillance
Morbidity and Mortality Weekly report
for Disease Control and Prevention.
Summary of notifiable diseases,
 Information on international reporting is from www.who.int/csr
 Information for disease summaries is from Levison and Jawetz 2000 and ODH’s Infectious Disease Control Manual (IDCM)
Surveillance for foodborne-disease outbreaks –
“Surveillance for waterborne-disease outbreaks – US, 1995-1996”, MMWR