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Infectious disease.pdf
- 2. INFECTIOUS DISEASE ▪ Infectious diseases: Diseases that are caused by the growth of microorganisms inside the body. Some of these diseases are contagious. Despite the availability of vaccines & antibiotics, they are still prevalent in all parts of the world. 3/8/2023
- 3. ▪ Infectious diseases are disorders in which tissue damage or dysfunction is produced by microorganisms. ▪ Despite the availability and use of effective vaccines and antibiotics, infectious diseases remain an important health problem worldwide. ▪ Infectious disease= transmissible disease = communicable disease. Definition :
- 4. ▪ Contagious mean person to person transmission. ▪ Non contagious acquired from sources such as animals, insects , soil, air or originating from normal microbial flora of the body.
- 5. Infectious agents belong to a wide range of classes, they include; 1- Prions: which are modified host proteins lacking genetic molecules. 2- Viruses: obligate intracellular parasites which only replicate intracellularly. 3- Bacteriophage and plasmid. 4- Bacteria: prokaryotes lacking nucleic acid and endoplasmic reticulum. Infectious agents:
- 6. 5-Mycoplasma, rickettsiae, Chlamydia. 6-Fungi: non-motile filamentous, branching strands of connected cells. 7-Protozoa: single cell organisms with a well defined nucleus. 8-Helminthes: multicellular parasites with complicated life cycles often involving several hosts.
- 7. 3/8/2023 © 2009, James L. Fishback, M.D. Some common infectious diseases are – 1.Diptheria 2.Whooping cough 3.Tuberculosis 4.Syphillis 5.Clostridial infection 6.Pneumonia
- 8. CATEGORIES OF INFECTIOUS AGENTS 3/8/2023
- 9. SPECIAL TECHNIQUES FOR DIAGNOSING INFECTIOUS AGENTS 3/8/2023
- 10. Some Recently Recognized Infectious Agents and Manifestations 3/8/2023
- 27. 3/8/2023 Tuberculosis Tuberculosis is caused by a bacterium called Mycobacterium tuberculosis. The physiology of M. tuberculosis is highly aerobic and requires high levels of oxygen.Depending on the portal of entry of the infection,on the degree of haematogenous spread,many organs and systems can be affected .The commonest sites of infection are the lungs or the lymph nodes.Tuberculosis infection and diseases, infects an estimated 20-43% of the world’s population.
- 28. 3/8/2023 Sign and symptoms: Common symptoms: • Chest pain • Coughing up blood • Productive cough Systemic symptoms: • Fever • Chills • Night sweats • Appetite loss • Weight loss
- 29. 3/8/2023 Diagnosis:1.TB skin test 2.TB blood test Treatment: Antimicrobial chemotherapy: 1st 2 months:isoniazid+rifampicin+pyrazinamide+ethambutol Next 4 months:isoniazid+rifampicin Prevention: Bacillus Calmette-Guerin (BCG) vaccine for infants.
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- 31. 3/8/2023 Syphilis • Syphilis is a sexually-transmitted infectious disease caused by Treponema pallidum, a gram-negative spirochaete. • Syphilis is a sexually-transmitted infectious disease caused by Treponema pal Syphilis is transmissible by – sexual contact with infectious lesions – from mother to fetus (congenital syphilis) – via blood product transfusion – through breaks in the skin that come into contact with infectious lesions. • If untreated, it progresses through stages: primary, secondary, latent and tertiary stages..
- 32. 3/8/2023 SIGN AND SYMPTOMS: Primary stages: The appearance of a single sore marks the first (primary) stage of syphilis symptoms, but there may be multiple sores. The sore appears at the location where syphilis entered the body. Secondary stages: Skin rashes and/or sores in the mouth, vagina, or anus mark the secondary stage of symptoms. The rash usually does not cause itching. This rash may appear as rough, red, or reddish brown spots both on the palms of the hands and/or the bottoms of the feet. Latent and tertiary stages: Without treatment, the infected person can continue to have syphilis in their body even though there are no signs or symptoms. This latent stage can last for years. In this stage of syphilis, the disease damages the internal organs, including the brain, nerves, eyes, heart, blood vessels, liver, bones, and joints. This damage can result in death.
- 33. 3/8/2023 Diagnosis: 1.Blood test 2.Testing fluid from a syphilis sore. Treatment: • Primary and secondary syphilis can be successfully treated with a single dose of penicillin. • Doxycycline may be used as an alternative in case of penicillin allergy. • Tertiary syphilis need to be treated with three penicillin injections, which are given at weekly intervals. While treatment can stop the infection, it cannot repair any damage that has already been caused by the tertiary syphilis. • Refrain from any kind of sexual activity or close physical contact with another person until the treatment is completed.
- 34. 3/8/2023 Clostridia infection Clostridium species are gram-positive bacilli that grow under anaerobic conditions and produce spores that are frequently present in the soil. Clostridium perfringens, which causes a wide range of symptoms, from food poisoning to gas gangrene. Sign and symptoms of Gas gangrene: • Air under the skin • Progressive swelling around a skin injury • Vesicle formation • Blisters filled with brown-red fluid • Moderate to severe pain • Pale skin color
- 35. 3/8/2023 Diagnosis: 1.Blood, fluid and tissue culture to test for C. perfringens. 2.MRI, CT scan or X-ray to check the presence of gas in tissues. Treatment: • . Rapid diagnosis &aggressive early treatment • Administer supplemental oxygen • Restore intravenous fluid volume • Ensure that tetanus immunity is adequate • Treatment is combined with antibiotics &debriment.
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- 37. 3/8/2023 Pneumonia • Pneumonia is a form of acute infection of the lungs characterized primarily by inflammation of the alveoli due to filling of the alveolar air spaces with inflammatory cells and exudate which makes breathing painful and limits oxygen intake. • Pneumonia can be caused by viruses, bacteria or fungi. • Pneumonia accounts for 18% of all deaths of children under five years old worldwide.
- 38. 3/8/2023 Signs and symptoms: • Most people who develop pneumonia initially have symptoms of a cold: – Sneezing – sore throat – Cough • These symptoms are then followed by – cough with sputum production (discolored and sometimes bloody) – high fever (sometimes as high as 1040 F) – shaking chills – feeling of being short of breath – chest pain that is often made worse by coughing feeling very tired or weak.
- 39. 3/8/2023 Diagnosis: • X-ray • Culture of the sputum • Treatment: Antibiotic is the mainstay of pneumonia treatment. • Community acquired pneumonia: – In the UK, empiric treatment with amoxicillin is recommended as the first line for community- acquired pneumonia, with doxycycline or clarithromycin as alternatives. – In the USA, the recommended treatment option is macrolides (such as azithromycin or erythromycin), and doxycycline have displaced amoxicillin as first- line outpatient treatment in adults.
- 40. 3/8/2023 • Nosocomial pneumonia: – Third- and fourth-generation cephalosporins and fluoroquinolones, carbapenems, aminoglycosides, and vancomycin. • Prevention with vaccination: – There are currently 2 types of pneumococcal vaccines: • pneumococcal conjugate vaccine (PCV13) • pneumococcal polysaccharide vaccine (PPSV23) • Infants and Children younger than 2 Years of Age – PCV13 is routinely given to infants as a series of 4 doses, one dose at each of these ages: 2 months, 4 months, 6 months, and 12 through 15 months. • Children >2 years to adults: – A single dose of PCV13 • All adults 65 years of age and older: – A single dose of PPSV23 vaccine.
- 41. 3/8/2023 © 2009, James L. Fishback, M.D.