[How can serology contribute to the diagnosis of parasitic diseases?]. / Comment la sérologie peut-elle aider à l'établissement du diagnostic des parasites?

From a technical standpoint the most widely used tests for serology include the ELISA (enzyme linked immunosorbent assay), the IFA (indirect fluorescence assay), and the immunoblot. ELISA tests are widely used as screening assays since they harbor a high sensitivity. The main pitfall of serologies is the frequency of cross-reactions, especially between the different helminths. This is why positive results should be confirmed by a second test method with a higher specificity. Results need also to be put in the perspective of the patient history, clinical signs and laboratory findings. Serological tests are most appropriate when the parasite cannot be documented by direct examination (by eye or under the microscope) and during the pre-patent period. Serologies for parasites are also useful when an unexplained eosinophilia is present.

Leprosy in a pregnant woman.

Herein, we describe a case of leprosy in a 29-year-old pregnant southeast-asian woman who presented with joint pain and multiple disseminated erythematous macules, papules and plaques. Histological examination and stains for acid-fast bacilli from skin biopsies substantiated the clinical suspicion of a cutaneous mycobacterial disease and both should be performed in all patients with unidentified skin lesions. The definitive laboratory diagnosis of leprosy was achieved by the application of a species-specific real-time polymerase chain reaction from infected tissue.