Q Fever as a Cause of Fever of Unknown Origin and Thrombocytosis: First Molecular Evidence of Coxiella burnetii in Brazil

Short Communication

Q Fever as a Cause of Fever of Unknown Origin

and Thrombocytosis: First Molecular Evidence

of Coxiella burnetii in Brazil

Elba R.S. Lemos,1 Tatiana Rozental,1 Maria Ange´ lica M. Mares-Guia,1 Daniele N.P. Almeida,1

Namir Moreira,1 Raphael G. Silva,1 Jairo D. Barreira,1 Cristiane C. Lamas,1

Alexsandra R. Favacho,1 and Paulo V. Damasco2

Abstract

We report a case of Q fever in a man who presented with fever of 40 days duration associated with thrombocytosis.

Serological and molecular analysis (polymerase chain reaction) confirmed infection with Coxiella

burnetii. A field study was conducted by collecting blood samples from the patient’s family and from the animals

in the patient’s house. The patient’s wife and 2 of 13 dogs showed seroreactivity. Our data indicate that C. burnetii

may be an underrecognized cause of fever in Brazil and emphasize the need for clinicians to consider Q fever in

patients with a febrile illness, particularly those with a history of animal contact.

Key Words: Brazil—Fever of unknown origin—Q fever—Serologic and molecular diagnosis—Thrombocytosis.

Qfever is a worldwide zoonosis caused by Coxiella

burnetii, a small obligate intracellular Gram-negative

bacterium of the order Legionellales. The disease has a broad

spectrum of clinical manifestations, ranging from a limited

febrile illness, pneumonia, and hepatitis to life-threatening

forms such as endocarditis and meningoencephalitis (Tissot-

Dupont and Raoult 2008, Cunha et al. 2009). Ticks, farm animals,

pets, and many wild animals are possible reservoirs of

infection. Transmission to humans is usually via inhalation of

contaminated aerosols from urine, feces, milk, and birth

products or less commonly by ingestion of unpasteurized

milk from infected farm animals. Occupational groups such as

veterinarians, farmers, and slaughterhouse workers are at

highest risk. Although Q fever is distributed throughout the

world, its distribution in Brazil, where it is not a reportable

disease, is poorly defined.

Since the first seroepidemiologic study was published in

1953, little additional information has become available and

only four cases associated with endocarditis have been confirmed

by serology or Gimenez staining of valves (Branda˜o

et al. 1953, Travassos et al. 1954, Ribeiro do Valle et al. 1955,

Riemann et al. 1974, Costa et al. 2006, Siciliano et al. 2008,

Lamas et al. 2009).

On October 13, 2008, a 47-year-old man from Itaboraı´, state

of Rio de Janeiro, in southeastern Brazil, was admitted to the

Gaffre´e Guinle University Hospital/UNIRIO with a fever of

>40 days duration, associated with abdominal pain, headache,

nausea, fatigue, malaise, and depression. Physical examination

was unremarkable, except for abdominal pain on

palpation.

Laboratory exams revealed a high erythrocyte sedimentation

rate (82mm in the first hour), leukocytosis (13,100/mm3)

with neutrophilia (74%), and thrombocytosis (611,000/mm3).

Bone marrow aspiration showed slight hyperplasia of the

monocyte–macrophage system and granulocytic cells. Echocardiogram

and tomographic scans of the abdomen and

thorax were normal. Treatment with a fourth-generation

cephalosporin (cefepime 4 g/day) was begun, but without

improvement.

The patient reported that 3 months before falling ill he had

purchased 12 goats (Saneen breed), some of them for personal

milk supply and some to sell to the community. The goats

1Laboratory of Hantaviroses and Rickettsioses, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil.

2Gaffre´e Guinle Hospital, Federal University of Rio de Janeiro—UNIRIO, Rio de Janeiro, Brazil.

Partial data of this study were presented as a poster at the XLV Brazilian Society of Tropical Medicine Meeting, Porto Alegre, Rio Grande

do Sul, Brazil, March 2009.

VECTOR-BORNE AND ZOONOTIC DISEASES

Volume 00, Number 00, 2010

ª Mary Ann Liebert, Inc.

DOI: 10.1089/vbz.2009.0261

1

were kept together with other animals, 14 dogs and 2 cats.

Additionally, the patient had a history of contact with the

birth products of three goats that had aborted, 3 weeks before

the onset of the symptoms.

Because of a high clinical suspicion of brucellosis, treatment

with doxycycline (200 mg/day) and rifampin (600 mg/day)

was begun and the fever disappeared in 4 days.

Serological testing for brucellosis, toxoplasmosis, leishmaniasis,

cytomegalovirus, hepatitis B and C, syphilis, bartonellosis,

ehrlichiosis, rickettsiosis, and histoplasmosis and

detection of circulating capsular polysaccharide antigen from

Cryptococcus neoformans performed on the first available serum

sample collected on 40th day after onset of illness were negative.

Mycobacteria, leishmania, and fungi cultures were also

negative. Two serum samples collected 40 and 70 days after

onset of the illness were tested for C. burnetii using a commercial

indirect immunofluorescence assay for IgG (Panbio).

Titers of specific antibodies to phase II antigen of 256 and 1024

were detected in the first and second serum samples, respectively.

After DNA extraction using a commercial kit (QIAamp

DNA; Qiagen), polymerase chain reaction (PCR) was performed

and heat shock proteins genes (htpAB) of C. burnetii

(687 bp) were amplified from the first serum sample DNA

(Hoover et al. 1992). The PCR was repeated without a positive

control and the result was confirmed, but DNA sequencing of

the amplicon detected was not possible because of insufficient

serum samples (Fig. 1). Rifampin was discontinued and the

patient was treated with doxycycline for 21 days.

In December 2008, a field investigation was carried out in

the patient’s home and blood samples from his family (wife

and daughter) and 13 dogs were collected for analysis. His

wife, who handled and fed them goat milk, told the investigators

that one of their dogs (a 7-month-old female) had died,

and another had aborted puppies, while the patient was in

hospital. The wife was seroreactive for C. burnetti (titer of antiphase

II IgG of 128) and 2 of the 13 dogs showed indirect

immunofluorescence assay (IFA) reactivity (titers of antiphase

II IgG of 64 and 128) but displayed no clinical manifestations.

Unfortunately, the goats had been sold to another

farmer so biological samples from these animals were not

available for analysis.

All the symptoms were resolved and the patient was discharged

at 4 weeks after admission. A third sample of the

patient’s serum collected at 6 months after the onset of illness

was analyzed and showed an IgG titer of 128 against phase II

antigens of C. burnetii.

Although several classical clinical descriptions of Q fever

have been recognized in different regions of the world, some

atypical and severe forms can be difficult to identify. Fever of

unknown origin, clinical pictures mimicking systemic inflammatory

disease, or lymphoproliferative disorders have

also been described (Tissot-Dupont and Raoult 2008, Cunha

et al. 2009). This article reports a case of Q fever presenting as

fever of unknown origin and thrombocytosis that recovered

after 3 weeks of treatment with doxycycline. Although

thrombocytopenia occurs in about 25% of patients in the early

phase of the illness, the presence of reactive thrombocytosis

has also been described during its later phase (Tissot-Dupont

and Raoult 2008, Cunha et al. 2009).

Studies of C. burnetii in humans and animals are

frequently based on serologic tests, and the prevalence of

C. burnetii infection varies widely from one country to another

(Tissot-Dupont and Raoult 2008). Our findings provide

definitive confirmation of Q fever in Brazil, where there are

no molecular studies documenting C. burnetii infection in

humans or animals. Anti-C. burnetii antibodies were also

detected in the patient’s wife and in two dogs, providing

further evidence of the circulation of C. burnetii in Itaboraı´,

Rio de Janeiro, Brazil.

Although the PCR results were positive, DNA sequencing

of the detected amplicon was not possible because of lack of

sufficient biological material in the first serum sample.

Further studies including molecular characterization of

C. burnetii are necessary to establish the extent and the importance

of Q fever in Brazil.

Disclosure Statement

No competing financial interests exist.

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FIG. 1. Agarose gel electrophoresis of Coxiella burnetii

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Address correspondence to:

Elba R.S. Lemos

Laboratory of Hantaviroses and Rickettsioses

Oswaldo Cruz Institute

FIOCRUZ

Pavilha˜o He´lio Peggy Pereira

Sala B116, FIOCRUZ

Avenida Brasil, 4365

Rio de Janeiro 22040-900

Brazil

E-mail: elemos@ioc.fiocruz.br

Coxiella burnetii IN BRAZIL 3