Evidence against rapid emergence of praziquantel resistance in Schistosoma haematobium, Kenya. (33/532)

We examined the long-term efficacy of praziquantel against Schistosoma haematobium, the causative agent of urinary schistosomiasis, during a school-based treatment program in the Msambweni area of Coast Province, Kenya, where the disease is highly endemic. Our results, derived from treating 4,031 of 7,641 children from 1984 to 1993, indicate substantial year-to- year variation in drug efficacy. However, the pattern of this variation was not consistent with primary or progressive emergence of praziquantel resistance. Mathematical modeling indicated that, at current treatment rates, praziquantel resistance will likely take 10 or more years to emerge.  (+info)

Cysticidal therapy: impact on seizure control in epilepsy associated with neurocysticercosis. (34/532)

OBJECTIVE: To evaluate the clinical features and seizure control of epilepsy related to neurocysticercosis. METHOD: 18 patients with partial epilepsy and neurocysticercosis were treated with albendazol or praziquantel and followed from 3 months to 12 years. We analyzed results from the CSF exam, interictal electroencephalogram (EEG), head computerized tomography and/or magnetic resonance imaging. RESULTS: The patients' mean age was 36.4 years. The mean duration of epilepsy was 16 years. 83% patients had simple partial seizures; 17% had complex partial seizures. All patients underwent routine EEGs: 62% had abnormalities and 38% were normal. A relationship was observed between focal EEG abnormality and the location of cyst in 28% of the patients. The CSF exams showed pleocytosis in 33% of the patients, and 28% had elevated protein levels. Only 22% of patients had positive titer for cysticercosis in the CSF. In all patients who had somatosensory and special sensory seizures there was a relationship between location of the cysts and seizure semiology (n=11). After cysticidal therapy, 83% patients had a significant improvement in controlling seizures. CONCLUSION: In this group, we found a predominance of simple partial seizures and a relationship between somatosensory and special sensory seizures and the location of the cysts. Cysticidal therapy was effective in controlling seizures in these patients and should be considered for patients with partial seizures and semiology related to cyst location.  (+info)

Efficacy of praziquantel against Schistosoma mansoni with particular consideration for intensity of infection. (35/532)

Chemotherapy with praziquantel is the cornerstone of schistosomiasis control. In view of recent concern about tolerance or resistance to praziquantel, monitoring its efficacy in different epidemiological settings is required. We report a study among 253 schoolchildren in an area highly endemic for Schistosoma mansoni in western Cote d'Ivoire. After examining four consecutive stool specimens from each child, the first praziquantel treatment at 60 mg/kg divided into two doses was administered. Four weeks later, stool specimens were again screened over 4 consecutive days and revealed a cure rate of 71.6% and an egg reduction rate of 79.9%. There was a significant association between cure rate and intensity of infection prior to treatment with highest cure rates observed in light infections (P < 0.01). Praziquantel, at a single dose of 40 mg/kg, was again administered 35 days after the first treatment. The overall cure and egg reduction rates increased considerably. The association between cure rate and intensity of infection prior to the second treatment was significant but less pronounced. Twenty-two children remained S. mansoni positive after the two chemotherapy campaigns, and interestingly, many of these were only identified after repeated stool examinations. We argue that pre-patent infections may account for some of these 'treatment failures'. However, further studies in other endemic settings are needed, with parasitological diagnoses having a high sensitivity.  (+info)

Primary muscle hydatidosis of the thigh: management of a complicated case with combination adjunctive albendazole and praziquantel chemotherapy. (36/532)

A patient had primary muscle hydatidosis of the thigh that was not detected radiologically or by fine-needle aspiration before surgery. The risk of dissemination during the initial exploratory procedure was high. Treatment consisted of formal muscle resection and combination therapy with albendazole and praziquantel. Clinical features of muscle hydatidosis and the role of adjunctive chemotherapy are reviewed.  (+info)

Treatment of Microcotyle sebastis infestation in cultured rockfish Sebastes schlegeli by oral administration of praziquantel in combination with cimetidine. (37/532)

The effect of cimetidine on the treatment efficacy of praziquantel against Microcotyle sebastis infestation in cultured rockfish Sebastes schlegeli was investigated. Juvenile rockfish were divided into 7 groups, and orally administered praziquantel alone (50, 100 and 200 mg kg(-1) body wt, BW) or in combination with cimetidine at a dose of 200 mg kg(-1) BW for each praziquantel dose. The fish in the control group were administered only saline. The results clearly showed that coadministration of cimetidine with praziquantel led to a significantly increased treatment efficacy of the latter drug, and consequently would lead to a lowering of the total dose of praziquantel, and a reduction in the administration times and costs for the treatment of M. sebastis infestation in cultured rockfish.  (+info)

Cellular immune responses of schistosomiasis patients are altered by human immunodeficiency virus type 1 coinfection. (38/532)

In vitro studies suggest that CD4(+) cells with a T helper 2 (Th2) phenotype better support human immunodeficiency virus type 1 (HIV-1) replication than do cells of the Th1 phenotype. As a result, Th2-type immune responses may be substantially affected by HIV-1 coinfection. To test this hypothesis, a comparison was done of proliferation and cytokine production by peripheral blood mononuclear cells from patients with schistosomiasis who were positive or negative for HIV-1. Patients with schistosomiasis with HIV-1 coinfections had significantly lower interleukin (IL)-4 and IL-10 production than did HIV-1-negative individuals. In contrast, interferon-gamma production levels were similar between the 2 groups. Furthermore, in patients with HIV-1, a decrease in CD4(+) T cells was correlated with an increased Th1:Th2 cytokine production ratio. The effect of praziquantel treatment on proliferation and cytokine responses also differed between HIV-1 infection groups. Thus, HIV-1 infection affects immune response patterns of patients with schistosomiasis.  (+info)

Schistosome calcium channel beta subunits. Unusual modulatory effects and potential role in the action of the antischistosomal drug praziquantel. (39/532)

Schistosomes are parasitic flatworms that cause schistosomiasis, a major tropical disease. The current drug of choice against schistosomiasis is praziquantel (PZQ), which has minimal side effects and is potent against all schistosome species. The mode of action of PZQ is unknown, though the drug clearly affects Ca(2+) homeostasis in worms, and there is indirect evidence for interaction of PZQ with schistosome voltage-gated Ca(2+) channels. We have cloned and expressed two Ca(2+) channel beta subunits, one from Schistosoma mansoni and one from Schistosoma japonicum. These two subunits (SmCa(v)beta A and SjCa(v)beta) have structural motifs that differ from those found in other known beta subunits. Surprisingly, coexpression of either SmCa(v)beta A or SjCa(v)beta with a cnidarian (CyCa(v)1) or mammalian (Ca(v)2.3) Ca(2+) channel alpha(1) subunit results in a striking reduction in current amplitude. In the case of Ca(v)2.3, this current reduction can be partially reversed by addition of 100 nm PZQ, which results in a significant increase in current amplitude. Thus, these unusual schistosome beta subunits can confer PZQ sensitivity to an otherwise PZQ-insensitive mammalian Ca(2+) channel, indicating that a possible target for PZQ action is the interaction between beta subunits and pore-forming alpha(1) subunits in schistosomes.  (+info)

Evaluation of efficacy of school-based anthelmintic treatments against anaemia in children in the United Republic of Tanzania. (40/532)

OBJECTIVE: To determine the impact of deworming on anaemia as part of a large-scale school-based anthelmintic treatment programme in the Tanga Region of the United Republic of Tanzania. METHODS: Both the reduction in the prevalence of anaemia and the cost per case prevented were taken into consideration. Cross-sectional studies involved parasitological examination and anaemia evaluation before and at 10 months and 15 months after schoolchildren were dewormed. FINDINGS: Baseline studies indicated that the prevalence of anaemia (haemoglobin < 110 g/l) was high (54%) among schoolchildren, particularly those with high intensities of hookworm and schistosomiasis. Attributable fraction analysis suggested that hookworm and schistosomiasis were responsible for 6% and 15% of anaemia cases, respectively. Fifteen months after deworming with albendazole and praziquantel the prevalence of anaemia was reduced by a quarter and that of moderate-to-severe anaemia (haemoglobin <90 g/l) was reduced by nearly a half. The delivery of these anthelmintics through the school system was achieved at the relatively low cost of US$ 1 per treated child. The cost per anaemia case prevented by deworming schoolchildren was in the range US$ 6-8, depending on the haemoglobin threshold used. CONCLUSIONS: The results suggested that deworming programmes should be included in public health strategies for the control of anaemia in schoolchildren where there are high prevalences of hookworm and schistosomiasis.  (+info)