After C. psittaci pneumonia was confirmed, one of the three male patients received symptomatic anti-infective treatment with moxifloxacin (400mg ivgtt qd) and with adjuvant non-invasive ventilator therapy. The other two male patients received symptomatic anti-infective therapy with doxycycline (100mg po q12h) and were treated with high flow nasal cannula therapy. All three male patients were improved and discharged after more than 10 days of treatment. Two female patients were transferred to our hospital after invasive ventilator adjuvant treatment with tracheal intubation from other hospitals. They were treated with moxifloxacin (400mg ivgtt qd) combined with doxycycline (100mg po q12h) for symptomatic anti-infective therapy. The two female patients were treated with ECOM and ventilator adjuvant therapy due to their critical illness. One patient was removed ECOM after five days of treatment with blood oxygen saturation and oxygen partial pressure was significantly improved. After 3 days of consecutive treatment, the invasive ventilator was removed. The patient continued to receive treatment and was discharged from the hospital. Another 35-years old female patient (case 5) was critically ill and the disease progressed rapidly and finally die. One week before admission, the B-mode ultrasound showed that the patient was in early intrauterine pregnancy with a size of about 6 weeks, with no germ and heartbeat. The patient was transferred to the respiratory ICU of our hospital after oral endotracheal intubation with a high fever of 39  C and blood oxygen saturation of 65%. Chest radiograph showed multiple exudative lesions in both lungs and pleural effusion on the right side. After admission, she was given meropenem combined with moxifloxacin and ganciclovir. On the third day after admission, mNGS of blood indicated C. psittaci, with a sequence number of 533. mNGS of BAFL indicated Klebsiella pneumoniae, with a sequence number of 175. Then the patient was given an injection of doxycycline. On the 7th day of admission, the patient's blood oxygen saturation was still 70% (through endotracheal intubation and invasive ventilator), and ECMO treatment was performed. On the 8th day of admission, the patient died due to septic shock, disseminated intravascular coagulation (DIC), and multiple organ failures.