Am. J. Trop. Med. Hyg., 87(2), 2012, pp. 345–348
Copyright © 2012 by The American Society of Tropical Medicine and Hygiene
Case Report: A Fatal Urban Case of Rocky Mountain Spotted Fever Presenting an
Eschar in San Jose´ , Costa Rica

Ana Patricia Argu¨ ello, Laya Hun,* Patricia Rivera, and Lizeth Taylor
Hospital Nacional de Nin˜ os, San Jose´, Costa Rica; Centro de Investigaciones en Enfermedades Tropicales (CIET), Facultad de Microbiolog?´a, Universidad de Costa Rica, San Jose´, Costa Rica
Abstract. This study reports the first urban human case of Rocky Mountain spotted fever caused by Rickettsia rickettsii, in Costa Rica. An 8-year-old female who died at the National Children’s Hospital 4 days after her admission, and an important and significant observation was the presence of an “eschar” (tache noire), which is typical in some rickettsial infections but not frequent in Rocky Mountain spotted fever cases.

Rocky Mountain spotted fever (RMSF) is an infectious
disease caused by the bacterial agent Rickettsia rickettsii.
Human infections are frequently reported throughout the
western hemisphere in countries such as Argentina, Brazil,
Canada, Colombia, Me´ xico, Panama´ , and United States.1,2
Nowadays, the international recommendation of the World
Health Organization (WHO) for the diagnosis of fever cases
with maculopapular rashes includes the analysis for spotted
group fever (SGF)-related rickettsial infection. In Costa
Rica, R. rickettsii, was first identified in 19773 and several
subsequent outbreaks have been reported since then, with
high mortality rates (~60%).4 Costa Rican cases5 are mostly
reported in areas north to the central volcanic system, specifically
in the towns of Limon, Sarapiqui, and San Carlos, as
well as in Turrialba (east) and San Ramo´n (west).5 All cases
were epidemiologically associated with the rain and tropical
forests characterized by dense vegetation, and large populations
of small rodents, which are highly infested with ticks,
the vector of the pathogens.
The incubation period for RMSF is ~3–12 days. A shorter
incubation period is usually associated with disease severity.
Only 60% of the RMSF patients remember a tick bite,
because these are painless and occur at body sites that people
usually overlook, like scalp, armpit, and lower legs. There are
a few reports of R. rickettsii infection with observable signs at
the site of the tick bite called eschars-touche noir,6 unlike the
ones observed with other rickettsial species such as Rickettsia
parkeri7 and Rickettsia massiliae.8 Clinical symptoms initiate
with high fever usually ³ 39.5°C, headache, generalized myalgia,
chills, and digestive problems including nausea, vomiting,
diarrhea, and anorexia. Because of the unspecificity of the
symptoms, RMSF is usually misdiagnosed for other infectious
diseases, such as leptospirosis, meningococcemia, enterocolitis,
or even dengue. As the disease progresses, a generalized
maculopapular rash may be observed that tends to concentrate
on hands and feet, and become petequial in the more
severe forms of the disease.2,9–11 Because of misdiagnosis,
fatal cases are usually associated with lack or late administration
of specific treatment. Here, we describe the first urban
human fatal case associated with RMSF disease, in the metropolitan
area of San Jose, the capital of Costa Rica, which presented
a tick bite eschar on the abdominal area.
On April 2, 2010, a female, 8 years and 11 months of age, a
resident of an urban area called San Rafael de Desamparados,
located ~6 km south of downtown San Jose, arrived at the
main children’s hospital in San Jose, Costa Rica (Hospital
Nacional de Nin˜ os-

[HNN]). At the time of admission, the
patient reported clinical symptoms of 7 days of evolution
characterized by frontal headache, fever, abdominal pain,
and severe myalgia. In the last 3 days, the patient developed
a maculopapular rash that started in both forearms and progressed
into a generalized exanthema mainly in palms and
soles. The patient reported suffering from asthma attacks that
were under clinical control. The mother of the patient denied
any recent visit to non-urban areas, not even to the city borders.
No other members of the family or neighbor reported
symptoms of the disease. The physical examination of the
patient at the time of arrival to the HNN, reported that the
patient was alert, conscious, with a generalized myalgia, and
dehydrated. The patient had a fever of 38.5°C, a heart rate
of 136 beats/minute, an oxygen saturation of 97%, the arterial
pressure of 84/30 mm of Hg with a mean arterial pressure
of 50 mm of Hg, conjunctival injection, and generalized
maculopapular rash, however more severe in face, palms, and
soles. Abundant petequia were observed in the lower limbs
and mucosa, and coalescent hemorrhagic lesions were present
in the inguinal area and thighs. No lymphadenopathies or signs
of neurological dysfunction were reported and a negative optical
return loss. Abdominal palpation was reported as soft and
very painful superficially as well as deep inside. Laboratory
cabinet tests at admittance were as follow: Hb: 11.5 g/dL,
leukocytes: 7 040/mL with 54% polimorphonuclear, 30% bands
and toxic granulation, platelets: 22,000/mL, and C-reactive protein:
248. Creatinine and ureic acid blood concentrations were
normal. Upon admission into the hospital the patient developed
hypotension, oliguria, hepatic dysfunction, and coagulopathy,
and was immediately transferred into the intensive
care unit where assisted respiration was initiated. Treatment
with gamma immunoglobulin was started because of the possibility
of Kawasaki disease. Electrocardiograms were relatively
normal with a mild decrease in the systolic function and the
coronaries had a normal appearance. On April 5, 3 days after
admission into the hospital, a laparoscopic abdominal surgery
was performed that showed no significant malfunctions.
*Address correspondence to Laya Hun, Centro de Investigaciones
en Enfermedades Tropicales (CIET), Facultad de Microbiolog?´a,
Universidad de Costa Rica, San Jose´ , Costa Rica. E-mail: [email protected]
Upon consultation with the infectologist, Kawasaki disease
was ruled out because the rashes were not characteristic of
this disease and instead rickettsiosis or staphylococcemia
should be considered first, but leptospirosis, ehrlichiosis, and
meningococcemia were also possible. Immediately, intravenous
ciprofloxacin treatment was applied at 360 mgs every
12 hours. By April 6, 4 days after hospital admission, all bacterial
cultures returned negative. On the same day, a neurologist
declared the patient brain dead.
Postmortem diagnosis (autopsy). The macroscopic findings
at the autopsy were as follow: a generalized maculopapular
exanthema; presence of hemorrhagic and centro-necrotic
papules in face, palms, and soles; numerous petequia distributed
in the lower limps, and confluent purpuric lesions on the
anterior and lower waist and both thighs (Figure 1A). Histologic
analysis showed a leukocytoclastic vasculitis with microclots
in different tissues and several organs, skin, hearth,
gastrointestinal tract, bladder, brain, and skeletal muscles.
The vasculitis was observed mainly in small communicating
vessels, arteries, and veins. A diffuse severe myocarditis associated
to the severe vasculitis (Figure 1B), a portal mononuclear
hepatitis, focal interstitial nephritis, and acute tubular
necroses were also noted. An important and significant
observation was the presence of an “eschar” (tache noire),
which is typical in some rickettsial infections, but not frequent
in RMSF cases. The lesion measured 9 mm in diameter, and
looked like a deep excavated necrotic ulcer, localized at the
left side of the paraumbilical zone (Figure 1C). Cultures of
lung fluids, cerebrospinal fluids, and blood were negative for
bacteria, fungi, and mycobacteria. Samples were sent to the
Center for Disease Control and Prevention (CDC, Atlanta,
GA) for immunohistochemical analysis for Leptospira and
Neisseria meningitidis, with negative results and positive for
SFG rickettsias. Polymerase chain reaction (PCR) for liver
and kidney were positive for Rickettsia sp. and negative for
HSV-1 and HSV-2, enterovirus, alphavirus, flavivirus, ehrlichia,
rubella, measles, and influenza A/Sw1.
Confirmatory (laboratory) Rickettsia rickettsii diagnosis.
Further analysis of samples recovered at the autopsy (e.g.,
brain, liver, spleen, lungs, blood, and skin), was performed
at the Laboratory of Virology, Facultad de Microbiolog?´a,
Universidad de Costa Rica.
In brief, PCR using SFG Rickettsia-specific primers, previously
designed for the detection of the citrate synthase
gene (gltA) of R. rickettsii,12 were performed and all the
tissue samples tested resulted positive. Worthwhile to mention
is the fact that the skin sample was taken from a site
near the eschar (not from the eschar itself), and this sample
showed the strongest PCR band. This would strongly suggest
that the eschar and the disease were a consequence of the
tick bite. Furthermore, macerated tissues were inoculated
into VERO E6 and primary chick embryo cell monolayers,
and incubated at 37°C in 5% CO2 for 7 days. Rickettsia
replication in the cell cultures was detected by Gime´nez
staining and later confirmed by immunofluorescence using
specific R. rickettsii antisera,13 as shown in Figure 1D and E.
Male guinea pigs were inoculated intraperitoneally with cell
lysates of positive infected cell cultures (1 +
106 and 1 +
cells, respectively). The animals were monitored daily for the
appearance of symptoms and weight loss. Infected animals
died 4–5 days after inoculation, presenting severe orquitis,
10–25% weight loss, and significant temperature rise, all consistent
with virulent R. rickettsii infections. Internal tissues of
affected animals were processed by PCR to detect the
ompA gene of SFG rickettsiae.14 Amplified PCR products
were sequenced using the Genetic Analyzer 3130 (Applied
Biosystems/HITACHI, CA, USA), edited and analyzed by
BLAST (basic local alignment search tool). The amplified
segments were also sent to the laboratory of Dr. Marcelo
Labruna at the School of Veterinary Medicine, Universidad
de Sao Paulo, Brazil, for corroboration of the results. All tissue
samples tested were positive by PCR for Rickettsia-specific fragments:
gltA and ompA and the sequences of amplified segments
showed a 100% homology with R. rickettsii. Both sequences
were analyzed in Brazil and Costa Rica. Rickettsia rickettsii was
identified as the responsible agent for the fatal outcome.
Initially, the clinical history did not reveal enough data to
guide the physicians to the proper diagnosis and some details
may have been overlooked. After the patient’s death, the
personnel of the pathology service at the HNN interviewed
her mother, who referred that the family had moved a few
weeks before to a new home and that the girl complained of
an insect bite on the abdominal area, where the eschar was
later found. She also mentioned that they had a pet dog, but
the dog was not at their home any more.
For another research project, some of the neighboring
dogs were bled for serological analysis and the dog belonging
to the patient (it was at another house) was seropositive for
R. rickettsii antibodies by indirect immunofluorescence (results
will be published separately).
Conclusions. Although rickettsial diseases have been
described previously in Costa Rica in several occasions; this
is the first report of a human fatal case presenting an eschar,
and the first report of an infection acquired in a residential
area of the capital city, San Jose´ .
Human cases of RMSF are usually related to tropical areas,
where the vector is able to complete its life cycle; however, a
few cases have been associated with urban environments. For
example, a fatal human case was reported in Rio de Janeiro,
Brazil, where a 48-year-old male acquired the infection from
his brother who was a carriage-horse driver. In this case
R. rickettsii was diagnosed by PCR alerting the health authorities
in Rio de Janeiro of the presence of the pathogen, which
was not reported in the area for more than three decades.
Furthermore, Freitas and others and Lamas and others15,16
reported that 9.33%of the horses in the area were seropositive
for SFG. Although the pathogenicity for horses is unknown,
they are currently used in urban and marginal areas of Brazil as
sentinels of the disease.
In the state of Sonora, Mexico, from 2003 to 2010 more
than 600 cases of rickettsial infection have been diagnosed,
most of them as a result of R. rickettsii infection of the pediatric
population, which were highly lethal. During 2009, the
lethality in the same area was 43% of a total of 21 registered
cases, especially caused by misdiagnosis of the disease and the
consequent lack or delayed application of specific treatment.
An aggravating factor is that most people have dogs in their
houses in Sonora, where the main rickettsial vector is the
brown tick of dogs (Rhipicephalus sanguineus).17
In recent years other species of ticks and fleas,2,18,19 and
some new species of Rickettsia have been associated with
disease in humans in the Americas.2,20,21 Although the pathogenic
mechanisms for most of them is still unknown, the
health personnel should be aware of potential rickettsial
infections in urban areas where rodents are present. This
case illustrates and emphasizes the importance of a good
initial clinical description, and the need to correlate it with
all the epidemiological information available from the patient,
to obtain the most accurate diagnosis in a timely manner. This
case also illustrates that zoonotic diseases are not restricted
to rural, selvatic areas. Therefore, it is also necessary to
take into account the possibility that this and other zoonotic
diseases could infect patients even if they came from an
urban area. This report urges medical professionals to assist
Figure 1. (A) Maculopapular rash with areas of central necrosis violacea. (B) Lymphocytic myocarditis with vasculitis in small vessels. (C) Skin
section of the lesion (Tache noire), showing necrosis and leukocytoclastic. (D) Gimenez staining of VERO E 6 cells infected with isolated
Rickettsia. (E) Immunofluorescense of VERO E6 cells infected with isolated R. rickettsii.
these cases promptly and with proper treatment to avoid
unnecessary lethality.
Received March 7, 2012. Accepted for publication April 17, 2012.
Acknowledgments: We thank Francisco Vega and Carlos Vargas
(University of Costa Rica) for providing excellent support and technical
assistance. The authors are also grateful to Marcelo Labruna
and his staff (Departamento de Medicina Veterinaria Preventiva e
Salude Animal, Universidade de Sao Paulo, SP, and Brazil) for his
generous help in confirming Rickettsia identity. We also thank
Adriana Troyo and Andres Moreira for providing support in the
collection of serum samples from dogs and David Loria for his kind
assistance in preparing the manuscript.
Financial support: This research was supported in part by grants
from Netropica (grant no.9-N-2008), the Universidad de Costa Rica
(project no. 803-A8-127), and by the Faculty of Microbiology, UCR,
project ED-541.
Authors’ addresses: Ana Patricia Argu¨ ello and Patricia Rivera,
Hospital Nacional de Nin˜ os – Pathology San Jose, San Jose, Costa
Rica, E-mails: [email protected] and [email protected]
Laya Hun and Lizeth Taylor, Universidad de Costa Rica – Centro de
Investigacio´n en Enfermedades Tropicales, Departamento de Microbiolog?
´a e Inmunolog?´a, Facultad de Microbiolog?´a San Jose, San Jose,
Costa Rica, E-mails: [email protected] and [email protected]
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