ndersen er an - Gundersen Health System

Authors:
Swapna Narayana, MBBS
Leah I. Metz, MD†
Internal Medicine Residency
Gundersen Lutheran Medical
Foundation
La Crosse, Wisconsin
†Dr Metz is now a Nephrology Fellow
at University of Iowa Health Care
Todd J. Kowalski, MD
Section of Infectious Disease
Department of Internal Medicine
Gundersen Lutheran Health System
La Crosse, Wisconsin
African Tick Bite Fever and Crocodile Meat–
Associated Salmonellosis Coinfection in a
Returning Traveler
ABSTRACT
A 44- year- old man developed fevers, myalgias, headache, and a vesicular rash after returning
from South Africa. A presumptive diagnosis of African tick bite fever was made and doxycycline
was started. The patient remained symptomatic, however, and stool culture eventually grew
Salmonella enterica subsp diarizonae. Further history revealed the patient ingested crocodile
meat during his trip. Serology eventually confirmed the diagnosis of African tick bite fever. All
clinical symptoms subsequently resolved following courses of doxycycline and ciprofloxacin.
Address for correspondence:
Todd J. Kowalski, MD
Mail Stop C02-007
Gundersen Lutheran Health System
1900 South Avenue
La Crosse, WI 54601
Telephone: (608) 775-4472
Fax: (608) 775-4476
email: tjkowals@gundluth.org
A
frican tick bite fever is an emerging infection
among travelers, usually caused by Rickettsia africae. 1
Salmonella enterica subsp diarizonae is a rare human pathogen
that is typically associated with reptile exposure. 2,3 We report
an interesting case of coinfection with African tick bite fever
immediately followed by crocodile meat–associated salmonellosis
in a traveler returning from South Africa.
CASE REPORT
A 44-year-old, previously healthy man was admitted to the
hospital with fevers, myalgias, and headache 10 days after returning
from a weeklong trip to South Africa. Activities during his trip
included foot- and vehicle-based photo safaris in the Kwa Zulu-
Natal province. Two days prior to returning home, he consumed
crocodile meat. One day prior to returning home, he went on a
foot safari and reported “bug bites” above his ankles the following
day. He did not recall a tick bite. Subsequently, he developed a
vesicular rash on his lower extremities bilaterally, and 4 days after
returning from Africa developed systemic symptoms of fever,
myalgias, headache, and fatigue. He denied diarrhea or abdominal
discomfort upon admission. He took no medications except
atovaquone/proguanil 250/100 mg for malaria chemoprophylaxis.
He had received typhoid vaccine intramuscularly 3 years earlier
and had completed hepatitis A and B immunization series.
Initial physical examination revealed a temperature of 39.1˚C,
pulse of 83 beats per minute, and blood pressure of 127/83 mm
Hg. The only notable finding on his physical examination was a
vesicular, punctate rash on his lower extremities bilaterally (Figure).
Admission laboratory values included hemoglobin concentration
of 14.0 g/dL (to convert to g/L, multiply by 10), white blood cell
count of 4900/μL (to convert to ×10 9 /L, multiply by 0.001), and
platelet count of 169 ×10 3 /μL (to convert to ×10 9 /L, multiply by
1.0). Electrolyte, creatinine, and liver transaminase concentrations
were within reference range. The results of 3 serial malaria smears,
blood cultures, urine cultures, dengue serology, and a chest
radiograph were unrevealing.
Based upon the symptoms, epidemiological exposure, and
characteristic rash, a presumptive diagnosis of African tick bite
fever was made, and doxycycline was initiated at a dosage of 100
mg orally twice daily. After 24 hours the patient was afebrile and
feeling much improved.
Hospital discharge was planned, but just prior to anticipated
discharge the patient redeveloped a fever (temperature, 40.1˚C). The
following day his fevers persisted, and he developed a cough, along
Vesicular, punctate rash visible on the patient’s lower extremities.
Gundersen Lutheran Medical Journal • Volume 5, Number 1, July 2008 17