dr hadeel fadhil FIBMS
pertussis (whooping cough)
Acute bacterial disease involving the resp tract.
The initial catarrhal stage has an insidious onset with irritating cough that gradually becomes paroxysmal, usually with in 1-2 wk & last for 1-2 month or longer.
Paroxysms are characterized by repeated violent cough ,
Paraxosyms frequently end with expulsion of clear, tenacious secretion , often followed by vomiting.
Infant less than 6 months old, adolescent & adults often do not have the typical whoop or cough paroxysms .
Morbidity is slightly higher in adult female than male.
In non immunised population, especially malnourished & multiple enteric & resp infection , pertussis is among the most lethal diseases of infant & young children.
Pneumonia is the most common
cause of death, fatal encephalopathy.
Pertussis has been recognized with increasing frequency in adolescents & young adults, whose symptoms varied in severity from mild to atypical resp illnesses.
Many of those cases occur in previously in immunized persons & indicate reduced immunity following immunization.
Para pertussis is similar but usually milder disease.
It usually occurs in school age children & is relatively infrequent.
Infectious agent:
Bordetella pertussis, the pertussis bacillus , B. parapertussis cause parapertussis.
Diagnosis is based on the recovery
of the etiologic organisms
from nasopharyngeal specimens
during the catarrhal
& early paroxysmal stager
on appropriate culture media.
()occurrence
Endemic disease common in children.
Outbreaks occur periodically . A mark decline in incidence & mortality rate during the past four decade, chiefly in communities with active immunization program & good nutrition & medical care are available.
reservoir
humans
Mode of transmission
Direct contact with discharge from respi mucus membrane of infected persons by the airborne route.
() incubation period: 7-20 days
Period of communicability
Highly communicable in the early catarrhal stage before the paroxysmal cough stage.
Communicability gradually decrease in about three week .
For control purposes the communicable stage extend from the early catarrhal stage to 3 wk after the onset of typical paroxysms in patient not treated with antibiotics .
When treated with erythromycin, the period of infectiousness usually in 5 days or less after the onset of therapy.
Susceptibility & resistance
Susceptibility : non-immunised individual.
Transplacental immunity in infants has not been demonstrated .
Incidence rate of recognized disease are highest in children under 5 years of age .
Milder & missed atypical cases occur in all age groups
Methods of control
A/ PREVENTIVE MEASURES:
1- educate the public about the danger of whooping cough & the advantages of the initiating immunization at 2 months of age & adhering immunization schedule
2- active immunization is recommended wit 3 doses of vaccine consisting of killed bacteria , usually in combination with diphtheria & tetanus toxoid
DTP is recommended to be given at 2,4 & 6 month of age , booster doses are recommended at 15-18 month of age & at school entry.
Vaccines containing pertussis are not recommended after the 7th birth day.
The vaccine can be given simultaneously with oral polio virus vaccine (OPV),
inactivated polio virus vaccine (IPV)
Haemophilus influenza type B (Hib)
Hepatitis B vaccine
MMR , at different sites.
A family history of convulsive seizure is not considered a contraindication to pertussis vaccine.
Pertusssis vaccine is not given to:
person 7 years of age or older , since reaction to vaccine may be increased
in older children & adults.
Those who experience severe reaction such as convulsions, collapse or temperature greater than 40.5 degree centigrade.
An anaphylactic reaction or acute encephalopathy within 48-72 hr of immunization is absolute contraindication to pertussis vaccine