| what is the name and causative agent of a disease first decribed by Bordet et al. in 1900, a disease that causes violent paroxysmal productive cough in children. | whooping cough, caused by Bordetella pertussis |
| the incubation period and site of infection for B. petussi is | 7-10 days, it infects the cilia of respiratory epithelium of infected children. |
| transmission of whooping cough is by | direct or droplet contact with naso[pharygeal secretion of an infected person. |
| the infection of whooping cough has 2 infection periods | 1) from predrome- 3wks after paroxysmal cough
2) 5 days after starting antibiotic treatment( what is the antibiotic treatment?) |
| what is the reservoir of bordetella pertussis | humans. there are no animal or insect vectors known. whooping cough is a child-hood infection |
| the virulence factors of B. pertussis include | 1) adhesins: filamentous heagglutinin(FHA) rbc agglutination, and fimbriae/pilli for adherence
2) toxins which include: pertusis toxin, adnylate cyclase toxin/hemolysin, tracheal cytotoxins and lethal toxins( dermonercrotic toxins) |
| the epidemiology of whooping cough | most severe in infants under 1 yr old. more than half of infant that get it will be hospitalised and some even die. in adults the disease is less severe and my not be recognised, althought infected adults can spread to infants. |
| clinical symptoms of pertussis | 1) catherrhal stage:first stage. lasts for 1-2 wks most infective stage. runny nose, nasal congestion, sneezing occassional cough, low grade fever.
2) paroxysmal stage: 2nd stage classical whooping cough and inspirational whoops, more at night where an average of 15 attacks in 24hrs. lasts for 1-6wks
3) convalescent stage: 3rd stage. cough with many complications: secondary bacterial pneumonia sub-conjugal hemorrhage, convulsions. lasts for weeks or months |
| lab diagnosis. | 1)culture: naso-pahrygeal swab is most convenient. there is also a cough plate of bordet-gengou media where patient coughs directly into.
2)fbc show leukocytosis, with ablolute lymphocytosis of 70-80%
3) DIT: serology withe ELISA and Indirect hemagglutination test.
4) PCR |
| what does whooping cough look like on culture media | greyish, smooth, opaque white refractile colonies resembling pearls or mercury droplets. |
| identification of B. pertussis | gram neg coccobaccilli, non motile and non sporeforming.
oxidase and catalase pos.
nitrate and urea negative |
| treatment | erythromycin makes illness less contagious, give early to reduce symptoms.
tetracycline, chloraphenicol and ampicillin |
| further measures to prevent spread of whooping cough | vaccination with DTP and persons with close contact should be treated with erythromycin |
