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Key Features

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Essentials of Diagnosis
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  • Psittacosis

    • Fever, cough, malaise, chills, headache

    • Diffuse rales; no consolidation

    • Long-lasting radiographic findings of bronchopneumonia

    • Isolation of the organism or rising titer of complement fixing antibodies

    • Exposure to infected birds (ornithosis)

  • Neonatal Chlamydophila (Chlamydia) conjunctivitis

    • Watery, mucopurulent, to blood tinged discharge and conjunctival injection presenting from a few days of life until 16 weeks of age

    • May be associated with neonatal Chlamydophila pneumonia

    • Identification of Chlamydophila conjunctivitis or pneumonia in a neonate should prompt evaluation and treatment of the mother and her sexual partner

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General Considerations
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  • Chlamydophila psittaci

    • When the pathogen is transmitted to humans from psittacine birds (parrots, parakeets, cockatoos, and budgerigars), the disease is called psittacosis

    • However, other avian genera (eg, pigeons and turkeys) are common sources of infection in the United States, and the general term ornithosis often is used

    • Human-to-human spread rarely occurs

    • Incubation period is 5–14 days

  • Chlamydophila pneumoniae (formerly Chlamydia pneumoniae)

    • May cause atypical pneumonia similar to that due to Mycoplasma pneumoniae

    • Transmission is by respiratory spread

    • Lower respiratory tract infection due to C pneumoniae is uncommon in infants and young children

    • Has been associated with acute chest syndrome in children with sickle cell disease

  • Chlamydophila trachomatis

    • In infants born to infected mothers, infection can be acquired through exposure in the birth canal, causing neonatal conjunctivitis and pneumonia

    • Risk of acquisition for a baby born vaginally to an infected mother is about 50%

    • "Trachoma"

      • Caused by certain C trachomatis serovars (A–C)

      • Seen in developing countries in Africa, Asia, Latin America, the Middle East, and some Pacific and East Pacific islands; rare in the United States

      • Most common cause of acquired blindness worldwide

      • Peak incidence is seen at 4–6 years of age, with scarring and blindness occurring in adulthood

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Clinical Findings

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Symptoms and Signs
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  • C psittaci pneumonia

    • Tends to be mild in children

    • Onset is rapid or insidious, with fever, chills, headache, backache, malaise, myalgia, and dry cough

    • Pneumonitis, altered percussion notes and breathe sounds, and rales

    • Pulmonary findings may be absent early

    • Dyspnea and cyanosis may occur later

    • Splenomegaly, epistaxis, prostration, and meningismus are occasionally seen

    • Delirium, constipation or diarrhea, and abdominal distress may occur

  • C pneumoniae pneumonia

    • Clinically similar to M pneumoniae infection

    • Most patients have mild upper respiratory infections

    • Lower respiratory tract infection is characterized by

      • Fever

      • Sore throat (perhaps more severe with C pneumoniae)

      • Cough

      • Bilateral pulmonary findings and infiltrates

  • C trachomatis neonatal conjunctivitis and pneumonia

    • Can occur from a few days until 12–16 weeks after birth

    • Mild to moderate swelling of the lids and watery or mucopurulent discharge may be present

    • Conjunctivae may be friable and there may be some bloody discharge

    • Pneumonia may occur in babies with or without neonatal conjunctivitis

      • Most commonly seen between 2 and 12 weeks of age

      • Most babies are afebrile and have tachypnea and a staccato cough

  • C ...

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