The patient was a previously healthy 41-year-old male forest policeman, which required him to have contact with wild animals in a virgin forest. His family members indicated that the patient on occasion hunted mammals (hares, civets, etc.) and drank stream water while on duty.
He was admitted to an emergency unit with a 4-day history of fever, adynamia, dry cough, and mental dysfunction. On physical examination, the patient exhibited a temperature of 39.0°C, heart rate of 80, blood pressure of 95/66 mm of Hg, and respiratory rate of 20. Blood chemistry revealed a hemoglobin of 6.2 g/dL (normal: 11–16), red blood cell count of 2,120,000/μL (normal: 3,500,000–5,500,000), white blood cell: 2,290/μL, with 42.8% neutrophils (normal white blood cell: 4,000–9,000; neutrophils 50–70%), platelets 9,000/μL (normal: 100,000–300,000), glucose 9.5 mmol/L (normal: 3.2–5.6),direct bilirubin 23.7 μmol/L (normal: 1.7–7.1), alanine aminotransferase 104 IU/L (normal: 4–40), aspartate aminotransferase 216 IU/L (normal: 8–40), lactic dehydrogenase 1,528 IU/L (normal: 114–240), triglyceride 3.21 mmol/L (normal: 0.37–1.80), ferritin 23,800 μg/L (normal: 20–280), fibrinogen 95 mg/dL (normal: 200–400). A blood culture was negative for bacteria and viruses. Serological testing for human immunodeficiency virus, hepatitis B virus, hepatitis C virus, and antinuclear antibody were negative. A chest x-ray revealed an interstitial and alveolar infiltrate. Hepatosplenomegaly was observed using B-ultrasonography and tomography.
On admission, the patient was given an empirical antimicrobial treatment with cefoperazone plus tazobactam and etimicin. However, fever, dyspnea, and dry cough persisted and his clinical condition rapidly worsened and mechanical ventilation was required by the third day following admission. On the fifth day, bone marrow was biopsied for further diagnosis. The patient finally died of multiorgan failure 8 days after admission. Bone marrow examination revealed a few nuclear cells and a great amount of T. gondii cysts and tachyzoites () using Wright's stain. The cyst sizes (N = 13) ranged from 10 to 25 μm.
A group of Toxoplasma gondii tachyzoites (arrow) in bone marrow smear of the patient, Wright's stain.
For further assessment of the pathogen, a bone marrow smear was submitted to the parasite research laboratory of Yunnan University. Total DNA from the bone marrow sample was isolated and polymerase chain reaction (PCR) analysis was performed using the T. gondii
-specific primer pairs TOX4 (CGCTGCAGGGAGGAAGACGAAAGTTG) and TOX5 (CGCTGCAGACACAGTGCATCTGGATT).7
The target fragment of 527 bp could be amplified from this sample (). The sequence of the PCR product was identical with the published sequence of T. gondii
Figure 2. Species-specific polymerase chain reaction (PCR) amplification of the 529 bp DNA fragment using the Toxoplasma gondii-specific primer pairs TOX4/TOX5. Lanes: 2 kb DNA ladder (M); negative control using TE buffer (A); positive control using T. gondii oocysts (more ...)