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Lecture 6 (Blastomycosis (cause is Blastomyces dermatitidis (normal…
Lecture 6
Blastomycosis
systemic fungal disease that begins as a respiratory infection
S/S: flu-like, produce lesions on face and upper body, or purulent lesions on various organs
cause is Blastomyces dermatitidis
normal growths in rich soil in organic material
in that cool, damp conditions favor growth and sporulation
pathogen yeast form at human body temp.
enters body through inhalation of dust carrying fungal spores in the lungs
in lungs the spores germinate to form yeast and multiply
Dx based on identifying fungus in clinical samples
examples are cultures, direct exam of sputum, bronchial washings, biopsies, CSF, or skin scrapings
treat with amphotericin B for teen weeks
relapse is common for AIDS patients
scientists have developed recombinant DNA vaccine against Blastomyces that gives protection in mice
Coccidioidomycosis
also called valley fever
S/S: fever, cough, chest pain, dyspnea, night sweats, weight loss, hemoptysis, HA, some have a rash
cause is Coccidioides immitis
found in soil and any activity that disrupts soil
assumes yeast form at human body temp
will germinate in alveoli into form called spherule
as the form matures it will enlarge and makes a large # of spores into the surrounding tissues
Dx by presence of spherules in clinical specimens
the dx is confirmed by injecting antigen beneath skin and observe an inflammation response
treat with amphotericin B
protective masks can prevent exposure to arthroconida
Histoplasmosis
S/S: asymptomatic in most cases, symptomatic infection causes coughing with bloody sputum or skin lesions
AIDS pts will develop an enlarged spleen and liver
cause is Histoplasma capsulatum
found in most soils that have high levels of N from bat droppings and birds
the pathogenic yeast forms at human body temperature
the virus produces several proteins that inhibit macrophages activation and other host defenses
humans inhale airborne spores from soil and fungus will attack alveolar macrophages in lungs
infected macrophages disperse the fungus beyond lungs by blood and lymph
Dx by identifying fungus in clinical samples and again with samples such as sputum, CSF, and various tissues
Parainfluenzavirus
3 strains cause coup and viral pneumonia
no specific antiviral treatment beyond support and careful monitoring of airways
must recover within two days
occur primarily in young children
Handwashing reduces spread of virus
Pneumocystis Pneumonia
S/S: difficult breathing, anemia, hypoxia, and fever, nonproductive cough
if left untreated will involve more and more lung tissue and eventually death
cause is Pneumocystis jirovecii
a normal member of the microbiome
can't survive on its own
transmitted by inhalation of droplets containing fungus
common disease in AIDS patients
Dx by clinical and microscopic findings
films usually reveal abnormal lung features
treat with trimethoprim and sulfamethoxazola
impossible to prevent infection with P. jirovecii
Metapneumovirus
estimated to be the second most common cause of viral respiratory disease
researchers found antibodies against virus form in all children by age 5
Cytomegalovirus