A 38-year-old man began to have symptoms of sore throat,
headache, myalgia, and fever (up to 38.3°C) on February 2,
2001. He had resided in Matzu, Taiwan for more than 30 years,
and had traveled to Mainland China in December 2000.
Laboratory tests disclosed thrombocytopenia (58000/mm3) and
leukopenia (3800/mm3). Because of the persistence of the
illness, he was transferred to the National Taiwan University
Hospital, Taipei, Taiwan on February 7, 2001. On admission,
his blood pressure was 138/85 mmHg and heart rate was 74
beats/min. His leukocyte count had returned to normal
(5670/mm3), however, proteinuria (>300 mg/ml) and elevation
of platelet count (78000/mm3) were noted. His
renal function was normal. He remained afebrile and his
general condition improved remarkably since the second day of
hospitalization. On the February 10, 2001, marked sinus
bradycardia (to as low as 33 beats/min) occurred (Figure
1(A)). Meanwhile, he did not complained of chest pain,
dizziness, or headache and his blood pressure remained
120-130/70-80 mmHg. Laboratory tests results showed the
electrolyte values were normal. There was no proteinuria and
serum values of creatinine kinase, MB fraction of creatinine
kinase, and troponin were normal. Echocardiography showed good
contractility of the left ventricle (ejection fraction, 80%).
Bradycardia (30-50 beats/min) persisted for 3 days, and his
heart rate returned to 60 to 80 beats/min since February 14,
2001 (Figure
1(B)
). He
was discharged on February 15, 2001 uneventfully.
Sera collected on days 5, 13, 18, and 32
after the onset of the illness were negative for IgM or
IgG of influenza viruses A and B, cytomegalovirus, Mycoplasma pneumoniae,
Dengue virus, Japanese encephalitis virus, and Rickettsia tsutsugamushi. A significant
increase of immunofluorescent IgG titres (from 1:320 to 1:5120)
and positive IgM titres of 1:80 against hantavirus antigen
(Seoul virus) were found.
This is the first documented indigenous case of
hantavirus infection in Taiwan. The possibility of his
acquiring the infection during his trip to Mainland China is
extremely low. This infection was caused by the Seoul virus
which also corresponded to the high seroprevalence rate of
this virus in rodents in Matzu. Marked sinus bradycardia (to
as low as 34 beats/min) in a patient with severe form of
hemorrhagic fever with renal syndrome has been reported but
this finding was not observed in patients with mild disease.
Marked sinus bradycardia should be included as a protean
manifestation of hantavirus infection and its mechanism needs
further investigation.
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