1.5 HAEMOPHILUjjjhhhhhhhhhhhhhhhhhhhhhS AND PNEUMOCOCCAL DISEASES_0fe09ba7ca6e442e98351d5bfc74a3c2.pptx

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1. HAEMOPHILUS INFLUENZAE & Bacterial Pneumonia & Meningitis Dr G Mulundu UNZA Sch of Medicine

2. Haemophilus influenzae type b Causes severe bacterial infections, particularly among infants 1 st believed to cause influenza (viral infection) 1930s Immunology and microbiology clarified this Isolated only from humans

3. Species of H influenzae I nclude:- H influenzae H parainfluenzae H aphrophilus H ducreyi Often reported to cause systemic illness incl. pneumonia, meningitis, arthritis, endocarditis, and soft tissue infections

4. Properties Non-motile, Gram-negative, Fastidious, Capnophilic Facultative anaerobe with 02 torelance Catalase and Oxidase positive 2 strains; unencapsulated and encapsulated → with 6 gen recog types of (a, b, c, d, e, and f) Requires pre-formed growth factors that are present in blood: factor X (hemin) and factor V (nicotinamide adenine dinucleotide [NAD])

5. Serotypes Unencapsulated  non- typable ( NTHi ) H. influenzae Encapsulated  6 serotypes (a-f) Type b H. influenzae (Hib) is the most virulent

6. The Organism -2 Unencapsulated strains less invasive, but able to induce an inflammation that may cause epiglottitis, otitis media, conjunctivitis, sinusitis and pneumonia i n all ages and meningitis in 6-60 months Capsule appear as 1y virulence factor as strains – ve of capsule do not cause bacteremia

7. H flu type b Epidemiology Reservoir Human Asymptomatic carriers Transmission Respiratory droplets Temporal pattern Peaks in cool – cold months Communicability Generally limited but higher in some circumstances

8. H influenzae type b & Pneumonia Organism colonizes nasopharynx In some persons, may invades bloodstream and cause infection at distant site (meningitis) Antecedent upper respiratory tract infection may be a contributing factor

9. Epidemiology of Pneumococcal Disease Reservoir Human carriers Transmission Respiratory Temporal pattern Winter and early spring Communicability Unknown , Probably as long as organism in respiratory secretions

10. Pneumococcal Disease S pneumoniae first isolated by Pasteur in 1881 was confused with other causes of pneumonia until discovery of Gram stain in 1884 More than 80 serotypes described by 1940 First U.S. vaccine in 1977

11. Diseases H. influenzae type b (Hib) Acute Bacterial Meningitis Bacteremia Pneumonia Epiglottitis Cellulitis Osteomyelitis Infectious Arthritis Unencapsulated H. influenzae Otitis Media Conjunctivitis Sinusitis Pneumonia Transmission by droplets/aerosols or direct contact with nasophryngeal secretions

12. Clinical Syndromes of Pneumococcal Disease May clinically manifest as: Pneumonia Bacteremia Meningitis

13. Pneumococcal Pneumonia: Clinical Features Abrupt onset Fever Shaking chills Pleuritic chest pain Productive cough Dyspnea , tachypnea , hypoxia

14. Epidemiology of Pneumococcal Pneumonia Estimated 175,000 hospitalizations per year (in US; >Africa) Up to 36% of adult community-acquired pneumonia and 50% of hospital-acquired pneumonia Common bacterial complication of influenza and measles

15. Chn at Increased Risk of Invasive Pneumococcal Disease Functional or anatomic asplenia , especially in: sickle cell disease HIV infection Recipient of cochlear / other ear implants Child care groups

16. Pneumococcal Bacteremia More than 50,000 cases per year (in US; >Africa) Rates higher among elderly and very young infants Case-fatality rate ~20%; up to 60% among the elderly

17. Burden of Pneumococcal Disease in Children (/yr in US) Syndrome Cases Bacteremia 13,000 Meningitis 700 Death 200 Otitis media 5,000,000

18. H influenzae type b Meningitis Accounted for approximately 50%-65% of cases in the prevaccine era Hearing impairment or neurologic sequelae in 15%-30% Case-fatality rate 2%-5% despite of effective antimicrobial therapy

19. Medical Management of Meningitis Often requires hospitalization Treatment with an effective 3rd generation cephalosporin, or chloramphenicol plus ampicillin Ampicillin -resistant strains now common throughout the world

20. Pneumococcal Meningitis Estimated 3,000 - 6,000 cases per year (in USA; > in Africa) Case-fatality rate ~30%, up to 80% in the elderly Neurologic sequelae common among survivors

21. Hib Risk Factors for Invasive Disease Exposure factors household crowding large household size child care attendance low socioeconomic status low parental education school-aged siblings Host factors race/ethnicity chronic disease

22. Pneumococcal Disease Outbreaks Outbreaks not common Generally occur in crowded environments (jails, nursing homes) Persons with invasive disease often have underlying illness May have high fatality rate

23. Pneumococcal Conjugate Vaccine Pneumococcal polysaccharide conjugated to nontoxic diphtheria toxin (7 serotypes) Vaccine serotypes account for 86% of bacteremia and 83% of meningitis among children >6 yrs

24. Pneumococcal Conjugate Vaccine Highly immunogenic in infants and young chn , incl those with high-risk medical conditions 97% effective against invasive disease caused by vaccine serotypes 73% effective against pneumonia 7% reduction in all episodes of acute otitis media

25. Vaccines Contraindications & Precautions Severe allergic reaction to vaccine component or following prior dose of vaccine Moderate or severe acute illness

26. Other Clinical Features

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