Therapeutic failure of praziquantel in the treatment of Schistosoma haematobium infection in Brazilians returning from Africa

Abstract

Schistosoma haematobium is present in about 53 African countries and in the Middle East, with the helminth showing high endemicity in these regions (CEGET-CNRSAtlas-WHO/1987, home page-WHO). Urinary schistosomiasis is an infectious disease of marked epidemiological importance for both natives and tourists exposed to the helminth in endemic regions.Treatment of urinary schistosomiasis has shown great advances with the introduction of praziquantel into the therapeutic arsenal (Bormann et al. 2001, De Clerq et al. 2002. Advantages of this drug include its easy administration (40 mg/kg body weight, a single dose by the oral route), low toxicity, and low intensity of side effects (McMahon 1983, Pugh & Teesdale 1983, Kahama et al. 1999, Rey 2001. These important factors have contributed to the tolerance with and easy application of individualized and mass treatments (Stephenson et al. 1989, King et al. 1992. Nevertheless, failure of praziquantel treatment of various proportions has been reported (Herwaldt et al. 1995, Liang et al. 2000. So, it is necessary to be sure about the + Corresponding author. E-mail: silva.iran@ig.com.br PATIENTS AND METHODSThree 24-h urine samples were collected from 26 patients at minimum intervals of one week. The patients were Brazilian military men who were part of the United Nation peace mission in Mozambique in 1994, age between 26 and 55 years old, median age of 29 years. The principal condition was the report of exposure in Licungo river and signals and symptoms affecting the genitourinary tract after exposure.Helminth eggs were recovered by spontaneous sedimentation and subsequent centrifugation of the urine sample. The total urine volume was transferred to glass chalices and left to stand for 24 h. After this period, 10 ml of the initial sediment was removed with a glass pipette held close to the bottom of the chalice and centrifuged at 3500 r.p.m. for 5 min. One-hundred microliters of the centrifuged material was removed with a glass pipette held close to the bottom of the tube, mounted on a slide, coverslipped, and observed under a microscope at magnifications of 100× and 400×. For endoscopic examination, an Olympus model 19 CH cystoscope with a 30 o eyepiece was used. 446 446 446 446 Schistosoma haematobium in Brazilians • • • • • Iran Mendonça da Silva et al.After the positive diagnosis, the patients were treated with 40 mg/kg body weight praziquantel administered in a single dose. Three other 24-h urine exams were repeated at 7-day intervals by the same technique, after a minimum period of 21 days after treatment. Treatment was repeated under medical supervision to ensure the correct use of the drug. In the case of suspicion of lesions, all individuals were submitted to cystoscopy followed by biopsy and histopathological examination at 6-month intervals, after each treatment or retreatment, under the same conditions as used for the initial diagnosis. The urine examination, with the same technique, was repeated after each cistoscopy.In the case of evidence of vesical involveme...

Praziquantel: its use in control of schistosomiasis in sub-Saharan Africa and current research needs

“…Evidence from in vitro cultures suggests that S. haematobium is marginally more sensitive to PZQ than S. mansoni (Botros et al 2005(Botros et al a, 2008. There are, however some case reports of S. haematobium infections failing to respond to treatment with PZQ (da Silva et al 2005 ;Alonso et al 2006).…”

Use of Cell-Free Circulating Schistosome DNA in Serum, Urine, Semen, and Saliva To Monitor a Case of Refractory Imported Schistosomiasis Hematobia

“…On the other hand, several cases refractory to repeated PZQ administration have been reported in countries where the disease is nonendemic, i.e., imported cases (18)(19)(20). It is speculated that schistosomiasis patients, who are rare in countries where the disease is nonendemic, tend to be followed up by detailed examinations, such as cystoscopy and bladder biopsy sampling, in addition to detection of ova, thus enabling identification of refractory cases.…”

Schistosomiasis haematobia: histopathological course determined by cystoscopy in a patient in whom praziquantel treatment failed

“…In this study, like N'GORAN et al, there were no complete signs of resistance to praziquantel 5 , then we considered therapeutic failure instead of resistance, because the parasite was not studied in vitro in resistance test. We presented in SILVA (2005) 6 , some cases with active granulomas and viable eggs after two controls, but in this presented case, these characteristics remained after seven treatments and four controls. The patient described in this study is one of the 26 cases reported in SILVA (2005) 6 .…”

“…We presented in SILVA (2005) 6 , some cases with active granulomas and viable eggs after two controls, but in this presented case, these characteristics remained after seven treatments and four controls. The patient described in this study is one of the 26 cases reported in SILVA (2005) 6 . The exposition was ten years before and, the first treatment was six years after the exposition.…”