5 However, following exposure, the median time to seroconversion is about 46 days, whereas clinical signs appear after about

30 days and ranges can be broad (1–12 wk).6,7 Therefore, there is an approximate 2-week seronegative window, requiring further serological testing to confirm seroconversion. The low sensitivity and delayed positivity of serological tests during the early phase of AS are due to the types of antigens (worm and egg) used for the tests. This www.selleckchem.com/products/PD-0332991.html lack of sensitivity and delayed positivity could be improved by new diagnostic tools. Cell-free parasite DNA detection of schistosoma in plasma is a promising solution for AS. The specificity is about 100% for Schistosoma mansoni, although the intrinsic quality of the test remains elusive given that the ideal primers are yet to be defined.8 Furthermore, this new tool needs more testing with Schistosoma haematobium and Schistosoma japonicum infection. Nonetheless this test should be used when facing a typical clinical situation find more after exposure in an endemic area. This test is not currently available. Culprit species are identified by analyzing eggs in human excreta (stools and urine), but this test lacks sensitivity. When testing is performed soon after infection the results are negative. The median detection time varies from 5 to 10

weeks after exposure. Early treatment with praziquantel (PZQ) delays oviposition by several weeks.7,9 It is worth noting that different phases of the parasitic lifecycle may overlap in a patient who is infected with many schistosomulae. Migrating schistosomulae may spend some ADP ribosylation factor time in the blood circulation before finding their way to the hepatic portal system and then to the peri-intestinal or peri-vesical blood vessels where they settle.4,10 This is not a synchronous process, and schistosomulae of different

stages of maturity coexist at a given time. In AS, schistosome egg excretion by mature schistosomes may thus coincide for several weeks with circulating schistosomulae.8,10 This has important treatment implications.9,11 PZQ, which is the major treatment of chronic schistosomiasis is ineffective on young (7- to 28-d-old) schistosomulae.12 Unsurprisingly, it does not prevent the chronic phase of the disease.7,13 Moreover, the use of PZQ during AS may be associated with paradoxical reaction (or Jarish Herxheimer-like reaction) in 40% of 10 French patients and 56% of 9 Belgian patients, respectively.7,9 Therefore, we should wait at least 3 months after exposure before initiating PZQ treatment when the chronic stage has been reached. In addition it will be necessary to repeat the administration of PZQ to ensure effective treatment to take into account the schistosomulae that may not yet have reached the adult stage. Corticosteroids may be prescribed in association with PZQ to avoid or attenuate this paradoxical reaction. Nonetheless there are some data arguing against this association.