1. Psittacosis (Ornithosis) – Caused by *Chlamydia psittaci* – Transmission: Inhalation of aerosolized feces, nasal secretions, or feathers from infected birds. – Symptoms: Fever, headache, myalgia, pneumonia (atypical), and possible extrapulmonary manifestations (e.g., hepatitis, encephalitis). – Diagnosis: Serology (IgM/IgG), PCR, or culture (high-risk, biosafety level 3). – Treatment: Doxycycline (100 mg PO/IV BID × 10–14 days) or macrolides (azithromycin 500 mg PO × 1 day, then 250 mg PO daily × 4 days) for mild cases. – Rationale: Doxycycline is first-line due to its efficacy against Chlamydiae; macrolides are alternatives for mild disease. –
2. Avian Tuberculosis – Caused by *Mycobacterium avium* complex (MAC), primarily *M. avium* subsp. *avium* or *M. genavense*. – Transmission: Inhalation of aerosolized droplets or ingestion of contaminated material. – Symptoms: Chronic, progressive weight loss, fever, night sweats, and pulmonary or disseminated disease (e.g., lymphadenopathy, hepatosplenomegaly). – Diagnosis: Acid-fast bacilli (AFB) staining, culture (slow growth), or molecular tests (e.g., PCR). – Treatment: Multidrug regimen (e.g., rifampin, ethambutol, clarithromycin, and moxifloxacin) for ≥12 months. – Rationale: MAC is intrinsically resistant to many antibiotics; prolonged therapy is required. –
3. Cryptococcosis – Caused by *Cryptococcus neoformans* or *C. gattii* (from pigeon droppings, but parrots can carry *C. neoformans*). – Transmission: Inhalation of fungal spores from contaminated droppings. – Symptoms: Pulmonary infection (cough, dyspnea) or meningitis (headache, fever, altered mental status). – Diagnosis: India ink stain, cryptococcal antigen (serum/CSF), or culture. – Treatment: Fluconazole (mild pulmonary disease) or amphoter
Context: [HarrisonPrincipleofInternalMedicine2025] that can be used to treat some infections. The prevalence of resistance... [HarrisonPrincipleofInternalMedicine2025] which the course of the illness can be inferred. In perplex - ing cases, it is useful to remember that uncommon presentations of common diseases are more likely than rare etiologies. Thus, even in... [HarrisonPrincipleofInternalMedicine2025] hypersensitivity reactions, inoculate toxins, transmit pathogens, create openings in the skin for secondary bacterial infection, and incite fear or disgust. Human beings are obligate hosts for few ectoparasites but can serve as facultative, dead-end, or paratenic (accidental) hosts for many others. ...
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