|
Clinical Features:
After an average incubation period of 1 week, symptomatic infections typically manifest as watery diarrhea, which can be severe.
Other symptoms include anorexia, weight loss, abdominal pain, nausea and vomiting, myalgias, low-grade fever, and fatigue.
Untreated infections typically last for 10-12 weeks and may follow a relapsing course.
Infections, especially in disease-endemic settings can be asymptomatic.
Laboratory Diagnosis:
Currently, the most practical
diagnostic method consists of the identification of oocysts in stool specimens by light
microscopy. Other methods are also available or under investigation.
Specimen processing:
Specimens should be refrigerated and sent to the diagnostic laboratory as rapidly as
possible. If it is not possible to send the specimen to the laboratory promptly, it should
be preserved. Ideally, because a range of tests might be desired, each of which has
different requirements of the specimen, the latter should be split in portions which
should be respectively:
- fixed in 10% formalin
(for direct microscopy, concentration procedures, and preparation of stained smears);
- fixed in 2.5% potassium
dichromate (for sporulation assays and molecular diagnosis); and
- frozen without fixation (for
molecular diagnosis).
Note: Specimens fixed in
sodium acetate-acetic acid formalin can be handled in the same manner as specimens fixed in
formalin; however, specimens fixed in polyvinyl alcohol (PVA) are of limited
value because they are not usable for concentration procedures.
Cyclospora oocysts can
be excreted intermittently and in small numbers. Thus:
- a single negative stool
specimen does not rule out the diagnosis; three or more specimens at 2- or 3-day intervals
may be required
- concentration
procedures should be used to maximize recovery of oocysts. The method most familiar to
laboratorians is the formalin-ethyl acetate sedimentation technique (centrifuge for 10
minutes at 500 × g). Other methods can also be used (such as the Sheathers flotation
procedure).
Microscopic examination:
The sediment can be examined microscopically with different techniques:
Diagnostic findings
Reference:
Eberhard ML, Pieniazek NJ, and
Arrowood MJ. Laboratory diagnosis of Cyclospora infections. Arch Pathol Lab Med 1997;121:792-797.
Treatment:
The recommended treatment for cyclosporiasis is a combination of two antibiotics,
trimethoprim-sulfamethoxazole*, also known as Bactrim, Septra, or Cotrim.
Supportive measures include management of fluid and electrolyte balance, and
rest.
For
additional information, see the recommendations in
The Medical Letter
(Drugs for Parasitic Infections).
* This drug is
approved by the FDA, but considered investigational for this purpose.
|
|