A 16 month old toddler presents with a 6 day history of fever, rhinitis, vomiting, profuse diarrhea, and poor feeding. His mother says that he has had up to 7 episodes of watery diarrhea per day. He has also lost 750g of weight during the last week. His medical history is significant for recurrent acute otitis media and rhinopharyngitis. He was recently treated with an antihistamine for a suspected respiratory allergy. His family and travel histories are unremarkable. All immunizations are up to date. His father is a dairy farmer.
Hb: 12.3 g/dL (10.5-13) Hct: 50% (36-47) WBC: 10,600/mm3 (6,000-17,500) Neutrophils: 46% (23-45) Lymphocytes: 41% (44-74) Monocytes: 10% (3-10) Eosinophils: 3% (0-5) Plt: 477,000/mm3 (150-450)
Na+: 130 mmol/L (135-145) K+: 4.0 mmol/L (3.5-5.2)
Negative for routine bacteria, rotavirus/adenovirus antigen, Giardia antigen, and Clostridium difficile antigen. Routine stool examination for enteric parasites is negative. Modified Ziehl-Neelsen staining of smear shows several Cryptosporidium oocysts. The Cryptosporidium antigen is detected by a Lateral Flow Test (LFT).
The polymerase chain reaction-restriction fragment length polymorphism (PCR/ RFLP) reveals Cryptosporidium parvum.