Neurocysticercosis in an Italian traveler to Latin America.
Neurocysticercosis is rarely reported in short-term travelers, although the disease remains a major public health problem in tropical regions. We present a case of neurocysticercosis that was probably acquired by ingestion of Taenia solium eggs contained in the stomach of a pig butchered by the traveler. Complete clinical resolution was obtained by medical treatment, underlying the importance of early suspicion and diagnosis of the disease. (+info)
Ivermectin distribution using community volunteers in Kabarole district, Uganda.
Ivermectin mass distribution for the control of onchocerciasis in Uganda began in 1991. This report describes a community based ivermectin distribution programme covering two foci in the Kabarole district which have an estimated 32,000 persons infected and another 110,000 at risk. Through nodule palpation in adult males, 143 villages were identified where nodule prevalence exceeded 20%. Skin snips were also taken from a sample of the population to measure changes in community microfilarial load (CMFL) with treatment. The delivery programme was integrated into the district health management structure, and used community volunteers supervised by medical assistants from adjacent health facilities for annual ivermectin distribution campaigns. After initial efforts by the community to support distributors in-kind proved inadequate, ivermectin distributors earned money retailing condoms as part of the social marketing component of district STD/AIDS programme. Reduction in the CMFL ranged from 40-62% twelve months after the second ivermectin treatment in three villages, and from 69-84% six months after the fourth round of treatment in two villages. After four years of treatment, 85% of eligible persons were receiving ivermectin from community volunteers in each treatment cycle. Drop out rates among volunteers did not exceed 20% over the four years reported here. The direct cost of treatment was US $0.29 per person. Among the reasons for low per-person treatment costs were the strong supervisory structure, the presence of health centres in the foci and a well developed and capable district Primary Health Care management team. (+info)
Efficacies of albendazole sulfoxide and albendazole sulfone against In vitro-cultivated Echinococcus multilocularis metacestodes.
The metacestode stage of Echinococcus multilocularis is the causative agent of alveolar echinococcosis (AE), a parasitic disease affecting the liver, with occasional metastasis into other organs. Benzimidazole carbamate derivatives such as mebendazole and albendazole are currently used for chemotherapeutic treatment of AE. Albendazole is poorly resorbed and is metabolically converted to its main metabolite albendazole sulfoxide, which is believed to be the active component, and further to albendazole sulfone. Chemotherapy with albendazole has been shown to have a parasitostatic rather than a parasitocidal effect; it is not effective in all cases, and the recurrence rate is rather high once chemotherapy is stopped. Thus, development of new means of chemotherapy of AE is needed. This could include modifications of benzimidazoles and elucidiation of the respective biological pathways. In this study we performed in vitro drug treatment of E. multilocularis metacestodes with albendazole sulfoxide and albendazole sulfone. High-performance liquid chromatography analysis of vesicle fluids showed that the drugs were taken up rapidly by the parasite. Transmission electron microscopic investigation of parasite tissues and nuclear magnetic resonance spectroscopy of vesicle fluids demonstrated that albendazole sulfoxide and albendazole sulfone had similar effects with respect to parasite ultrastructure and changes in metabolites in vesicle fluids. This study shows that the in vitro cultivation model presented here provides an ideal first-round test system for screening of antiparasite drugs. (+info)
Effect of anthelmintic treatment on sexual maturation in prepubertal beef heifers.
Heifers treated with ivermectin at weaning have been reported to reach puberty at a younger age and lighter weight than untreated heifers. We tested the hypothesis that heifers administered ivermectin would respond with earlier follicular development and a greater LH response to a 1-mg estradiol-17beta challenge (E2C) than untreated heifers. Fall-born Angus heifers (n = 32) were randomly assigned on 284 +/- 9 d of age (215.5 +/- 20.8 kg) to receive ivermectin (IVR) or albendazole (ALB), IVR + ALB, or to remain as untreated controls (CONT). Each group (n = 8) was housed separately in adjacent pens throughout the trial and managed to gain .8 kg/heifer on a ration containing 13.2% CP, 58.8% TDN, and 49.9% DM. The CONT heifers received an additional 2.27 kg/heifer of corn silage and 1.59 kg/heifer of corn daily to maintain ADG at comparable levels. Individual body weight was recorded weekly, and nematode eggs per gram (EPG) of feces were measured every 21 d. Ultrasonography was performed on alternate days starting 2 wk prior to E2C to characterize follicular wave patterns. Follicles were separated into classes (C1 [3 to 5 mm], C2 [6 to 9 mm], and C3 [10 mm]) and sizes (largest [LF], second [SLF], third [TLF], and fourth largest follicles [FLF]). The sizes of the regressing dominant follicle 1 (DF1) and the progressing dominant follicle 2 (DF2) were also determined. Serum concentrations of LH were determined from hourly jugular blood samples collected 8 to 24 h after injection of E2C. The IVR + ALB treatment group had more C3 follicles than ALB and CONT (P < .07). The IVR-treated heifers had larger TLF than ALB and CONT (P < .04). The IVR- and IVR + ALB-treated heifers had larger FLF and DF2 than ALB and CONT (P < .1). Least squares means for DF2 were 9.5 +/- .5, 8.0 +/- .4, 9.5 +/- .3 and 8.3 +/- .3 mm, for IVR, ALB, IVR + ALB and CONT, respectively (P = .02 for treatment effect). The E2C-induced serum LH concentration did not differ with respect to treatment. We conclude that heifers administered IVR display increased follicular development, supporting our earlier investigations regarding reduced age at puberty in heifers treated with IVR near weaning. (+info)
Cost of school-based drug treatment in Tanzania. The Partnership for Child Development.
It has been argued that targeting delivery of anthelmintics to school-children by taking advantage of the existing education infrastructure and administrative system can be one of the most cost-effective approaches in minimizing the intensity of infections with both schistosomiasis and major intestinal nematodes in many developing countries. The study was conducted in January 1997, shortly after the completion of the drug intervention programme. This paper provides an analysis of the costs of providing age-targeted treatment of school-children for urinary schistosomiasis using praziquantel and for intestinal nematodes using albendazole as an integral part of the School Health Programme in Tanga Region, Tanzania. The analysis shows that the total financial cost of the intervention programme in 1996 prices was US$54 252.28 (exchange rate: TSH 573 = US$1). Of this amount, the cost of drugs constitutes 80.6%, while the delivery cost appears relatively low, representing just below 20%. Even when the opportunity cost of unpaid days of labour input is included, the cost of drugs still remains the highest cost component of the intervention (55.8%). In the current epidemiological and logistic setting of Tanzania, the financial cost per child treated using praziquantel, which involved prior screening at the school level, was US$0.79, while treatment using albendazole was as low as US$0.23, of which US$0.20 was drug purchase cost. It is concluded that the base cost of delivering a universal, standard, school-based health intervention such as albendazole can be as low as US$0.03 per child tested, but even a very slight increase in the complexity of delivery can have a very significant impact on the cost of intervention. (+info)
Evidence for an improvement in cognitive function following treatment of Schistosoma japonicum infection in Chinese primary schoolchildren.
A double-blind, placebo-controlled, treatment trial was conducted in Sichuan, China to investigate the unique and combined effects on the cognitive function (working memory) of children after treating geohelminth infections with albendazole and treating Schistosoma japonicum infection with praziquantel. One hundred eighty-one children 5-16 years of age participated. At baseline, the praziquantel and placebo groups were similar in all background characteristics. Three months after praziquantel treatment, there was a significant reduction in the prevalence and intensity of S. japonicum infection. There were significant age group by praziquantel treatment interaction effects in three of the five cognitive tests, Fluency, Picture Search, and Free Recall, with effects being strongest in the youngest children (5-7 years old). Exploratory analysis within the youngest children showed a significant positive main effect of treatment on Fluency (P < 0.001), after controlling for sex, anthropometric, and parasitic and iron status. There was also a treatment by height-for-age interaction (P = 0.03) and a treatment by iron status interaction (P = 0.024) on Fluency. There was a treatment by S. japonicum intensity interaction (P < 0.001) on Free Recall, but the main effect of treatment on Picture Search was not significant (P = 0.058). Younger children and those who are physically the most vulnerable are likely to benefit the most from the treatment of S. japonicum infection in terms of improved performance on tests of working memory. (+info)
Presystemic metabolism of albendazole: experimental evidence of an efflux process of albendazole sulfoxide to intestinal lumen.
Albendazole (ABZ) presystemic clearance was studied in rat by perfusion of a 25 microM ABZ solution in isolated intestinal loops. Significant secretion of the active metabolite, ABZSO, into the lumen was observed. The metabolite was also present in mesenteric blood. After 30 min of intestinal perfusion, 64% of the ABZ dose had disappeared from lumen. The total amount of ABZSO measured was 0.341 +/- 0.04 nmol/cm with 0.176 +/- 0.03 nmol/cm in mesenteric blood. The metabolite secretion to intestinal lumen was 0.165 +/- 0.05 nmol/cm. Intestinal sulfoxidation was induced by repeated administration of ABZ and ABZ coadministered with surfactants, especially polysorbate 80. The enantioselectivity of the in vitro intestinal sulfoxidation of ABZ showed that the relative contribution of P-450 and flavin-containing monooxygenase was quite similar, but after the induction by ABZ coadministered with polysorbate 80, the cytochrome P-450 system contribution was significantly increased. The appearance of ABZSO in mesenteric blood clearance was also increased under these conditions. (+info)
Population biology of human onchocerciasis.
Human onchocerciasis (river blindness) is the filarial infection caused by Onchocerca volvulus and transmitted among people through the bites of the Simulium vector. Some 86 million people around the world are at risk of acquiring the nematode, with 18 million people infected and 600,000 visually impaired, half of them partially or totally blind. 99% of cases occur in tropical Africa; scattered foci exist in Latin America. Until recently control programmes, in operation since 1975, have consisted of antivectorial measures. With the introduction of ivermectin in 1988, safe and effective chemotherapy is now available. With the original Onchocerciasis Control Programme of West Africa coming to an end, both the new African Programme for Onchocerciasis Control and the Onchocerciasis Elimination Programme for the Americas, rely heavily on ivermectin self-sustained mass delivery. In consequence, the need for understanding the processes regulating parasite abundance in human and simuliid populations is of utmost importance. We present a simple mathematical framework built around recent analyses of exposure- and density-dependent processes operating, respectively, within the human and vector hosts. An expression for the basic reproductive ratio, R0, is derived and related to the minimum vector density required for parasite persistence in localities of West Africa in general and northern Cameroon in particular. Model outputs suggest that constraints acting against parasite establishment in both humans and vectors are necessary to reproduce field observations, but those in humans may not fully protect against reinfection. Analyses of host age-profiles of infection prevalence, intensity, and aggregation for increasing levels of endemicity and intensity of transmission in the Vina valley of northern Cameroon are in agreement with these results and discussed in light of novel work on onchocerciasis immunology. (+info)