What is Pertussis Bordetella pertussis also referred to as Whooping Cough Whooping cough is a...
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PertussisWhats All The Whoop About
What is PertussisBordetella pertussis also referred to as Whooping Cough
Whooping cough is a disease caused by a fastidious pathogen that invades the respiratory system. This pathogen secretes a toxin that disrupts the normal function of cilia in the lungs, resulting in a severe cough.
Gram-negative, aerobic coccobacillus
Humans are the only known host of pertussis.Bordetella pertussis is found in the mouth, nose, and throatIncidencePertussis occurs year-round, peaking in the later part of the year.
Annual incidence peaks every three to five years.
Adolescents and adults represent over half of the reported cases nationally. Even among highly vaccinated populations, waning immunity leads to a substantial number of susceptible older children and adults.
Adolescents and adults can serve as an important reservoir for transmission to young infants, who are at increased risk for serious complications
Outbreaks are more likely in fall and winter during cold and flu season
PrevalencePrevalence:Not all cases of whooping cough are reported or even diagnosed. Many cases of whooping cough are misdiagnosed due to individuals who have partial immunity (had only some of the required vaccinations) because their cough is less severe and mimics a common cold.
There are approximately 40,000,000 cases of whooping cough reported annually across the world.
In 2010, approximately 27,550 cases were reported in the United States, the most since 1959. source: CDC Whooping cough is the most common vaccine-preventable disease seen in the U.S.
SymptomsClinical symptoms of pertussis are similar to those of other infections:Runny noseNo or low grade feverCough
These symptoms also appear with croup or bronchiolitis respiratory syncytial virus (RSV) in children, viral or bacterial pneumonia, and other causes of chronic cough in adults therefore, isolation of the bacterium and confirmation of the pertussis diagnosis if very important, particularly if an outbreak is suspected.
Symptoms appear between 6 to 21 days (average 7 10) after exposure
Pertussis: Three StagesCatarrhal stage (prodromal stage; indistinguishable from the common cold): Runny noseSneezingMild coughLow-grade fever Malaise
Paroxysmal stage:After a week or two, Pertussis can be distinguished from the common cold by the paroxysm associated with coughing.; cough ending in a high-pitched inspiratory whoop sound, hence the name whooping cough.Coughing fits can last up to 12 weeks (which is why whooping cough is often referred to as the 100 day cough). Fever is absent or minimal.
Convalescent stage:Period of recovery as the cough slowly becomes less violent and the respiratory system begins to heal. May take up to 3 weeks to completely recover from B. pertussis.People with mild pertussis may have a persistent cough but without the whooping sound
TransmissionWhen an infected person coughs or sneezes, tiny germ-laden droplets are sprayed into the air and breathed into the lungs of those nearby.
A coughing attack can be very forceful; the velocity of air from a vigorous cough through the nearly closed vocal cords can approach 500 miles per hour.
Pertussis is transmitted through respiratory and nasal secretions.Pertussis is transmitted through dropletsTransmissionPertussis is highly contagious
Want proof? A person with pertussis will infect almost everyone in their household if those people arent vaccinated.
As many as 80% of immunized household contacts of symptomatic cases acquire infection, mainly because of waning immunity.
People with pertussis should avoid contact with others until they have been treated with antibiotics for five daysThink Pertussis THINK of pertussis in anyone with the following symptoms, regardless of vaccination history:
A cough in a person who has been notified of a close exposure to pertussis, A paroxysmal cough of any duration, with whooping, post-tussive vomiting/gagging or apnea, or
A persistent cough of unknown etiology, lasting more than seven days.
Pertussis can strike at an ageDiagnostic TestingSeveral types of laboratory tests are commonly used for the diagnosis of Bordetella pertussis. Culture is considered the gold standard because it is the only 100% specific method for identification. Other tests that can be performed include :
polymerase chain reaction (PCR) and serology
Serologic tests are more useful for diagnosis in later phases of the disease.
For the CDC single point serology, the optimal timing for specimen collection is 2 to 8 weeks following cough onset, when the antibody titers are at their highest; however, serology may be performed on specimens collected up to 12 weeks following cough onset.
Diagnostic TestingCulture testing is the criterion standard for B pertussis infection, owing to its high specificity (100%) for identification.
The best time frame for nasopharyngeal specimen collection for culture testing is within the first 2 weeks of cough onset, when viable bacteria are present.
Diagnostic TestingThe best, but most difficult way is to try to detect the causative organism (Bordetella pertussis) in the back of the nose. This usually involves passing a swab on a wire through a nostril to the back of the throat and sending it to a medical lab to culture the material.
This may take 5 to 7 days. If Bordetella pertussis or parapertussis grows this is usually taken as proof that it is whooping cough.
Communicability of PertussisPrevent The SpreadPatients are most infectious early in the illness, but communicability may persist for three weeks after onset of cough.
During the first week of illness, symptoms resemble the common cold, and paroxysmal coughing gradually develops during the second week of illness.
Antimicrobial therapy decreases communicability and may limit the spread of disease.
The bacteria is shed in nasopharyngeal secretions (droplets) and spreads when secretions get into mucous membranes such as the mouth, nose, eyes, or non-intact skin, especially when droplets are disseminated during coughing and sneezing.
The incubation period for pertussis is usually 7 to 10 days, but can range from four to 21 days.
Advise patients with suspect pertussis to stay home from school, work, or other activities during which they could expose others until they have completed five full days of appropriate antimicrobial treatment.
Exception: If onset of cough was more than three weeks prior, the patient is no longer infectious, even if the cough persists.
Communicability / Infectiousness
Inform patients with suspected pertussis to stay at home and avoid close contact with others until they have:
Completed the fifth day of an appropriate antibiotic OR Had cough symptoms for at least three weeks.
VDH Definition of close contact: within 3 feet of infected patient for: (a)1 hr continuous period, or (b) 10 hrs/week.
Cases are potentially infectious for the first three weeks of cough. Infectiousness after AntibioticPatients are considered to be non-infectious after completing the fifth day of appropriate antimicrobial treatment; however, they should complete the full regimen to avoid bacterial relapse.
The standard recommendations for a five-day course will remain unchanged until new data from comparative studies are available. Some health care providers are prescribing a one- or -three-day course of azithromycin (Zithromax) in place of the five-day course that is currently one of the standard pertussis treatment options. While this may be appropriate for some respiratory illnesses, the data from published randomized clinical trials using a three-day course for treatment of pertussis are insufficient. Assessing Potential ContactsContacts of pertussis cases may include:
Household members (who stay overnight in the same household)Day care contacts in the same home day care or in the same classroom within a day care center (in part because of the increased severity of disease in very young children)Persons who have had direct face-to-face contact with an infectious pertussis case during coughing or sneezingStudents participating in extracurricular activities with a pertussis case at least 10 hours per weekOther persons spending at least 10 hours per week with an infectious case, during which time they are frequently in close proximity (i.e., within arms length)Other contacts identified by public health in an outbreak situation
Local public health will work with the patient and the community to identify close contacts
ProphylaxisAntimicrobial prophylaxis of close contacts:
Antimicrobial prophylaxis (same regimen as therapy for cases) may be recommended to patients who are asymptomatic but are close contacts of pertussis cases. Antimicrobial prophylaxis is recommended if exposure to an infectious case occurred within the previous 21 days (the maximum incubation period for pertussis). Asymptomatic contacts receiving prophylaxis should not be excluded from their usual activities. Symptomatic contacts should be evaluated as suspect pertussis cases. In general, antimicrobial prophylaxis isn't recommended until there has been laboratory confirmation of the suspect case.
Post Exposure for Healthcare WorkersData on the need for postexposure antimicrobial prophylaxis in T-dap immunized HCWs are inconclusive.
If 21 days have lapsed since onset of cough in the index cause, chemoprophylaxis has limited value.
Source: American Academy of Pediatrics Red BookImmunization of Case ContactsImmunization of case contacts