Reduction In Infection Intensity Research Articles

Pre-and post-treatment evaluation of intestinal inflammation in Giardia and Blastocystis infected children: a community-based study.

Giardia intestinalis and Blastocystis hominis cause frequent infections in children in developing countries. However, the role of intestinal inflammation in their pathogenesis is still poorly understood. Faecal calprotectin (FC) level is used as an indicator of intestinal inflammation and neutrophil migration in the intestinal tract. The present study aimed to evaluate intestinal inflammation by measuring FC level among children infected with either G. intestinalis or B. hominis before and after treatment. Stool samples were collected from 282 children inhabiting a rural area in Egypt and examined microscopically for intestinal parasites. FC level was estimated in a group of children infected with G. intestinalis (n = 12) or B. hominis (n = 12) before and 3weeks after receiving nitazoxanide (200mg twice daily for 3days) and compared to a control group (n = 18) of parasite-free children. Cases of mixed infection were excluded. Nitazoxanide cure rate was 83% in both infections with a remarkable reduction of infection intensity in uncured children. The difference in FC levels between infected children and controls was not statistically significant. Also, the difference between the pre- and post-treatment estimations was not statistically significant. Elevated levels were observed before treatment in three children (two infected with G. intestinalis and one with B. hominis) who displayed normal post-treatment levels. Although G. intestinalis and B. hominis infections appear to cause no remarkable intestinal inflammation, they may induce abnormally elevated FC levels in a subset of children.

Preventive role of probiotic bacteria against gastrointestinal diseases in mice caused by Giardia lamblia.

Giardiasis is one of the most prevalent gastrointestinal diseases in the world. It is caused by Giardia, Giardia lamblia, a common and opportunistic zoonotic parasite. The aim of our work is to find a natural and safe alternative treatment for giardiasis, specifically, to determine if probiotic bacteria (Lactobacillus acidophilus, Bifidobacterium bifidum, and Lactobacillus helveticus) can contribute to treatment, and act as preventives. Sixty weanling albino mice, Mus musculus, were divided into control and experimental, probiotic-fed groups. We determined infection intensity, and cure and prevention rates of giardiasis through ELISA (enzyme-linked immunosorbent assay) of stool samples and histopathological comparison of intestinal tissue. In experimental groups, there was a significant reduction in infection intensity (P<0.001) on days 10, 15, and 20, while cure rate reached 87.5%. The control group showed no signs of reduced infection or cure and only the group treated with probiotics prior to infection showed significant prevention rates. In the experimental groups, intestinal changes due to giardiasis appeared 7 days post-infection. However, almost all of these changes disappeared by the 25th day. Our results suggest a beneficial and significant effect of probiotics in the prevention and treatment of giardiasis in mice.

Comparison of the Change in the Prevalence and Intensity of Schistosoma haematobium Infection Between High and Low Prevalence Areas of White Nile State, Sudan

This study aimed to investigate whether mass drug administration (MDA) intervention has an equivalent effect on reducing the prevalence and intensity of Schistosoma haematobium infection regardless of the baseline values. A repeated cross-sectional survey was performed targeting students of 12 primary schools in Al Jabalain and El Salam districts of White Nile State, Sudan, at both 1 week before and 8 months after the MDA. Prior to the baseline survey, school-aged children in Al Jabalain had received MDA interventions twice in 4 years, while those in El Salam had not. The baseline prevalence was 9.1% in Al Jabalain and 35.2% in El Salam, which were reduced to 1.8% and 5.5% at 8 months after the MDA, respectively. The corresponding reduction rates were 80.3% and 84.4%, not significant difference between both districts. However, changes in the geometric mean intensity (GMI) of egg counts were significantly different between both districts. The baseline GMIs were 14.5 eggs per 10 ml of urine (EP10) in Al Jabalain and 18.5 EP10 in El Salam, which were reduced to 7.1 and 11.2 EP10 after treatment, respectively. The corresponding reduction rates were 51.0% and 39.5%. In conclusion, MDA interventions were found to bring about similar relative reduction in prevalence regardless of the baseline value; however, the relative reduction in infection intensity was more salient in the district with a low baseline value for both prevalence and intensity. This clearly points to the importance of repeated MDA interventions in endemic areas, which will eventually contribute to schistosomiasis elimination.

Characteristics of persistent hotspots of Schistosoma mansoni in western C\xf4te d\u2019Ivoire

BackgroundPreventive chemotherapy with praziquantel is the cornerstone of schistosomiasis control. However, in some social-ecological settings, the prevalence and/or intensity of Schistosoma infection does not lower meaningfully despite multiple rounds of preventive chemotherapy, a phenomenon termed persistent hotspot (PHS). We assessed the characteristics of PHS in a Schistosoma mansoni-endemic area of Côte d’Ivoire.MethodsIn October 2016, a cross-sectional survey was conducted in 14 schools in the western part of Côte d’Ivoire, one year after multiple rounds of preventive chemotherapy. In each school, 50 children aged 9–12 years provided two stool samples and one urine sample. Stool samples were subjected to triplicate Kato-Katz thick smears for S. mansoni diagnosis. Urine samples were examined by a filtration method for S. haematobium eggs. PHS was defined as failure to achieve a reduction in the prevalence of S. mansoni infection of at least 35% and/or a reduction of infection intensity of at least 50%. Six schools underwent more detailed investigations, including a questionnaire survey for demographic characteristics and a malacological survey.ResultsIn the six schools subjected to detailed investigations, the overall prevalence of S. mansoni and S. haematobium was 9.5% and 2.6%, respectively. Four schools were classified as PHS. The S. mansoni prevalence in the four PHS was 10.9% compared to 6.6% in the remaining two schools. The S. mansoni infection intensity, expressed as arithmetic mean eggs per gram of stool (EPG) among infected children, was 123.8 EPG in PHS and 18.7 EPG in the other two schools. Children bathing in open freshwater bodies were at higher odds of S. mansoni infection (odds ratio: 4.5, 95% confidence interval: 1.6–12.6). A total of 76 human-water contact sites (53 in PHS and 23 in the other schools) were examined and 688 snails were collected, including potential intermediate host snails of Schistosoma (Biomphalaria pfeifferi, Bulinus forskalii, Bu. globosus and Bu. truncatus).ConclusionChildren in PHS schools bathed more frequently in open freshwater bodies, and hence, they are more exposed to Schistosoma transmission. Our findings call for an integrated control approach, complementing preventive chemotherapy with other interventions, particularly in PHS settings.

Saccharomyces boulardii reduces the mean intensity of infection in mice caused by the consumption of liver contaminated by Toxocara canis.

Probiotics have shown promising results as a potential method to control toxocariasis in mice inoculated with embryonated eggs of Toxocara canis. This study aimed to evaluate the protective effect of Saccharomyces boulardii in mice fed in natura chicken livers infected with T. canis. Twenty 15-day-old male Sussex chickens were inoculated with 300 T. canis embryonated eggs via intragastric catheter (GI). After 72h of infection, each liver was collected and individually offered to a group of 20 mice. Mice that received supplemented ration with S. boulardii (1.107 colony forming units) and consumed in natura chicken liver showed reduction in infection intensity of 67.1%. This study demonstrated that administration of S. boulardii has potential as a probiotic to assist in controlling visceral toxocariasis caused by the consumption of viscera from paratenic hosts containing infective parasite larvae.

Differential impact of mass and targeted praziquantel delivery on schistosomiasis control in school-aged children: A systematic review and meta-analysis.

BackgroundSchistosomiasis is a widespread public health concern in the poorest regions of the world. The principal control strategy is regular praziquantel administration to school-aged children in endemic areas. With calls for the elimination of schistosomiasis as a public health problem, expanding praziquantel delivery to all community members has been advocated. This systematic review and meta-analysis compares the impact of community-wide and child-targeted praziquantel distribution on schistosomiasis prevalence and intensity in school-aged children.Methodology/Principal findingsWe searched MEDLINE, Embase and Web of Science to identify papers that reported schistosome prevalence before and after praziquantel administration, either to children only or to all community members. Extracted data included Schistosoma species, drug administration strategy, number of treatment rounds, follow-up interval and prevalence and intensity before and after treatment. We used inverse variance weighted generalised linear models to examine the impact of mass versus targeted drug administration on prevalence reduction, and weighted boxplots to examine the impact on infection intensity reduction. This study is registered with PROSPERO, number CRD42018095377.In total, 34 articles were eligible for systematic review and 28 for meta-analysis. Schistosoma mansoni was reported in 20 studies; Schistosoma haematobium in 19 studies, and Schistosoma japonicum in two studies. Results of generalised linear models showed no detectable difference between mass and targeted treatment strategies on prevalence reduction in school-aged children for S. mansoni (odds ratio 0.47, 95%CI 0.13–1.68, p = 0.227) and S. haematobium (0.41, 95%CI 0.06–3.03, p = 0.358). Box plots also showed no apparent differences in intensity reduction between the two treatment strategies.Conclusions/SignificanceThe results of this meta-analysis do not support the hypothesis that community-wide treatment is more effective than targeted treatment at reducing schistosomiasis infections in children. This may be due to the relatively small number of included studies, insufficient treatment coverage, persistent infection hotspots and unmeasured confounders. Further field-based studies comparing mass and targeted treatment are required.

Persistent Hotspots in Schistosomiasis Consortium for Operational Research and Evaluation Studies for Gaining and Sustaining Control of Schistosomiasis after Four Years of Mass Drug Administration of Praziquantel.

.Control of schistosomiasis presently relies largely on preventive chemotherapy with praziquantel through mass drug administration (MDA) programs. The Schistosomiasis Consortium for Operational Research and Evaluation has concluded five studies in four countries (Côte d’Ivoire, Kenya, Mozambique, and Tanzania) to evaluate alternative approaches to MDA. Studies involved four intervention years, with final evaluation in the fifth year. Mass drug administration given annually or twice over 4 years reduced average prevalence and intensity of schistosome infections, but not all villages that were treated in the same way responded similarly. There are multiple ways by which responsiveness to MDA, or the lack thereof, could be measured. In the analyses presented here, we defined persistent hotspots (PHS) as villages that achieved less than 35% reduction in prevalence and/or less than 50% reduction in infection intensity after 4 years of either school-based or community-wide MDA, either annually or twice in 4 years. By this definition, at least 30% of villages in each of the five studies were PHSs. We found no consistent relationship between PHSs and the type or frequency of intervention, adequacy of reported MDA coverage, and prevalence or intensity of infection at baseline. New research is warranted to identify PHSs after just one or a few rounds of MDA, and new adaptive strategies need to be advanced and validated for turning PHSs into responder villages.

Evaluating the use of garlic (Allium sativum)for the remedy ofCryptocaryon irritansin guppies (Poecilia reticulata)

Garlic (Allium sativum) has been shown to possess antimicrobial properties against a range of disease-causing agents, including fish parasites. Our study aimed to investigate the potential use of garlic as a treatment against Cryptocaryon irritans infection, using guppies (Poecilia reticulata) as the fish model. Garlic was freeze-dried, powdered, and used as it is or as an aqueous extract. The content of allicin, its main active ingredient, was 1.25 mg/g in garlic powder and 0.82 mg/ml in the aqueous extract, as determined by HPLC analysis. Aqueous garlic extract fully immobilized C. irritans theronts and protomonts within 20 and 40 min, respectively, following exposure to 5 µl/ml. Treatment trials were performed, in which infected fish were fed with garlic powder-supplemented feeds (5%, 10%, or 20% supplementation), bathed in garlic aqueous extract (250 or 500 µl/L) and subjected to a combined treatment which included both feeding and bathing. Results revealed that the tested treatments failed to cure the infection, though reduction in infection intensity on the caudal fin, but not on the gills, was evident following dietary supplementation with 20% of powdered garlic in one of the trials.

Use of quantitative PCR to assess the efficacy of albendazole against Necator americanus and Ascaris spp. in Manufahi District, Timor-Leste

BackgroundSoil-transmitted helminths (STHs) including Ascaris lumbricoides, Necator americanus, Ancylostoma spp. and Trichuris trichiura are cause of significant global morbidity. To mitigate their disease burden, at-risk groups in endemic regions receive periodic mass drug administration using anthelmintics, most commonly albendazole and mebendazole. Assessing the efficacy of anthelmintic drugs is important for confirming that these regimens are working effectively and that drug resistance has not emerged. In this study we aimed to characterise the therapeutic efficacy of albendazole against Ascaris spp. and N. americanus in Timor-Leste, using a quantitative polymerase chain reaction (qPCR) method for parasite detection and quantification.ResultsA total of 314 participants from 8 communities in Timor-Leste provided stool samples before and 10–14 days after the administration of a single 400 mg dose of albendazole. Helminth infection status and infection intensity (measured in Ct-values and relative fluorescence units) were determined using qPCR. Efficacy was determined by examining the cure rates and infection intensity reduction rates. Albendazole was found to be highly efficacious against Ascaris spp., with a cure rate of 91.4% (95% CI: 85.9–95.2%) and infection intensity reduction rate of 95.6% (95% CI: 88.3–100%). The drug was less efficacious against N. americanus with a cure rate of 58.3% (95% CI: 51.4–64.9%) and infection intensity reduction rate of 88.9% (95% CI: 84.0–97.0%).ConclusionsThe observed cure rates and infection intensity reduction rates obtained for Ascaris spp. and to a lower extent N. americanus, demonstrate the continued efficacy of albendazole against these species and its utility as a mass chemotherapy agent in Timor-Leste. Furthermore, this study demonstrates the usefulness of qPCR as a method to measure the efficacy of anthelminthic drugs. Additional research is necessary to translate Ct-values into eggs per gram in a systematic way.Trial registrationAustralian and New Zealand Clinical Trials Registry 12614000680662 (registered 27 June 2014).

Immunogenetic novelty confers a selective advantage in host–pathogen coevolution

The major histocompatibility complex (MHC) is crucial to the adaptive immune response of vertebrates and is among the most polymorphic gene families known. Its high diversity is usually attributed to selection imposed by fast-evolving pathogens. Pathogens are thought to evolve to escape recognition by common immune alleles, and, hence, novel MHC alleles, introduced through mutation, recombination, or gene flow, are predicted to give hosts superior resistance. Although this theoretical prediction underpins host-pathogen "Red Queen" coevolution, it has not been demonstrated in the context of natural MHC diversity. Here, we experimentally tested whether novel MHC variants (both alleles and functional "supertypes") increased resistance of guppies (Poecilia reticulata) to a common ectoparasite (Gyrodactylus turnbulli). We used exposure-controlled infection trials with wild-sourced parasites, and Gyrodactylus-naïve host fish that were F2 descendants of crossed wild populations. Hosts carrying MHC variants (alleles or supertypes) that were new to a given parasite population experienced a 35-37% reduction in infection intensity, but the number of MHC variants carried by an individual, analogous to heterozygosity in single-locus systems, was not a significant predictor. Our results provide direct evidence of novel MHC variant advantage, confirming a fundamental mechanism underpinning the exceptional polymorphism of this gene family and highlighting the role of immunogenetic novelty in host-pathogen coevolution.

Combining Footwear with Public Health Iconography to Prevent Soil-Transmitted Helminth Infections.

Shoes are effective for blocking soil-transmitted helminths (STHs) that penetrate the skin. Unfortunately, shoe-wearing is uncommon in many areas where STHs are prevalent, in part because local populations are unaware of the health benefits of wearing shoes. This is especially true in low-literacy populations, where information dissemination through written messages is not possible. We launched a public health intervention that combines a public health image with sandals. The image is a "lenticular image" that combines two alternating pictures to depict the efficacy of shoes for preventing STH infection. This image is adhered to the shoe, such that the message is linked directly to the primary means of prevention. To create a culturally appropriate image, we conducted five focus group discussions, each with a different gender and age combination. Results of focus group discussions reinforced the importance of refining public health messages well in advance of distribution so that cultural acceptability is strong. After the image was finalized, we deployed shoes with the image in communities in western Uganda where hookworm is prevalent. We found that the frequency of shoe-wearing was 25% higher in communities receiving the shoes than in control communities. Microscopic analyses of fecal samples for parasites showed a sustained reduction in infection intensity for parasites transmitted directly through the feet when people received shoes with a public health image. Our results show that combining culturally appropriate images with public health interventions can be effective in low-literacy populations.

Modulation of IL-12 and IFNγ by probiotic supplementation promotes protection against Toxocara canis infection in mice.

In this study, supplementation with the probiotic Saccharomyces boulardii promoted a reduction in intensity of infection by Toxocara canis and modulates cytokines mRNA expression in experimentally infected mice. IL-12 gene transcription had 40-fold increase in S.boulardii supplemented uninfected mice and sevenfold increase in supplemented infected mice comparing with not supplemented group. Regarding IFNγ, similar results were observed, since probiotic supplementation induced approximately 43-fold increase, but only in uninfected mice (P<0·05). T.canis infection upregulated IL-10 expression while S.boulardii downregulated it and no change was observed for IL-4. Thus, based in these findings; we suggest that one possible mechanism responsible for S.boulardii protection effect against T.canis infection is by the modulation of cytokines expression, especially IL-12.

Praziquantel efficacy against Schistosoma mansoni among HIV-1 infected and uninfected adults living in fishing villages along Lake Victoria, Northwest Tanzania.

BackgroundAnimal studies have demonstrated that functional immune responses, as determined by the levels of CD4+ cell counts and anti-schistosome antibodies responses, determine the efficacy of praziquantel. Based on this evidence, it has been hypothesised that the immunodeficiency effects of the human immunodeficiency virus (HIV)-1 infection may affect the efficacy of praziquantel in co-infected human hosts. Thus, the present study assessed the efficacy of praziquantel by comparing parasitological cure rates and the reduction in infection intensity in HIV-1 seronegative individuals infected with S. mansoni and HIV-1 seropositive individuals co-infected with S. mansoni, following treatment with a single oral dose of praziquantel.MethodsThis was a prospective longitudinal study which included, at baseline, 555 S. mansoni infected adults aged 21–55 years, who were either co-infected or not with HIV-1 and who lived in fishing villages along Lake Victoria in Northwest Tanzania. These individuals were treated with a single oral dose of praziquantel (40 mg/kg) and, at 12 weeks, single stool samples were obtained and examined for S. mansoni eggs using the Kato-Katz technique. Finger prick and venous blood samples were collected for HIV-1 screening and CD4+ cell quantification.ResultsThe parasitological cure rate did not differ significantly from the HIV-1 serostatus (P = 0.12): among the co-infected individuals, the cure rate was 48.3% (14/29), and among the individuals infected only with S. mansoni, the cure rate was 62.6% (329/526). The egg reduction rate did not vary with the HIV-1 serostatus (P = 0.22): 77.22% for HIV-1 seronegative and 75% for HIV-1 seropositive individuals. The level of CD4+ cell counts (median 228 cells/μL: range 202–380 cells) did not influence the cure rate (P = 0.23) or the reduction in the intensity of the infection (P = 0.37).ConclusionThe HIV-1 infection per se or its moderate immunodeficiency effects, demonstrated by the range of CD4+ cell counts observed in co-infected individuals, did not affect praziquantel efficacy, as measured by the parasitological cure rate and the reduction in intensity of infection in the present study cohort.Electronic supplementary materialThe online version of this article (doi:10.1186/2049-9957-3-47) contains supplementary material, which is available to authorized users.

Formulation and Clinical Efficacy of Myrrh Extract in Hard Gelatin Capsules

The development of myrrh extract from natural origin capable of eradication of schistosomal infections has gained the interest of many scientists. Recently; myrrh extract is considered as the drug of choice from natural origin used to treat Schistosomiasis. This work includes the preparation of myrrh extract by maceration and the formulation of these extracts in hard gelatin capsules as a pharmaceutical dosage form followed by clinical investigation of the effectiveness of these capsules. As a result, myrrh extract capsules with different doses showed a variable effectiveness against Schistosoma mansoni (S. mansoni) with different severity but n-hexane extract capsules showed better effectiveness in comparison to alcohol extract capsules. The percent cure increased by increasing the treatment time. In additions the number of positive cases decreased by increasing the treatment time. On the contrary, increasing the severity of the infection from mild to heavy cases led to decrease the cure percent and increased the number of the positive cases. There was a significant reduction of infection intensity in cases which were incompletely cured. It could be concluded from these results that hard gelatin capsules of myrrh extract are highly effective as a pharmaceutical dosage form against Schistosomiasis.

Significantly Reduced Intensity of Infection but Persistent Prevalence of Schistosomiasis in a Highly Endemic Region in Mali after Repeated Treatment

BackgroundPreventive chemotherapy against schistosomiasis has been implemented since 2005 in Mali, targeting school-age children and adults at high risk. A cross-sectional survey was conducted in 2010 to evaluate the impact of repeated treatment among school-age children in the highly-endemic region of Segou.Methodology/Principal FindingsThe survey was conducted in six sentinel schools in three highly-endemic districts, and 640 school children aged 7–14 years were examined. Infections with Schistosoma haematobium and S. mansoni were diagnosed with the urine filtration and the Kato-Katz method respectively. Overall prevalence of S. haematobium infection was 61.7%, a significant reduction of 30% from the baseline in 2004 (p<0.01), while overall prevalence of S. mansoni infection was 12.7% which was not significantly different from the baseline. Overall mean intensity of S. haematobium and S. mansoni infection was 180.4 eggs/10 ml of urine and 88.2 epg in 2004 respectively. These were reduced to 33.2 eggs/10 ml of urine and 43.2 epg in 2010 respectively, a significant reduction of 81.6% and 51% (p<0.001). The proportion of heavy S. haematobium infections was reduced from 48.8% in 2004 to 13.8% in 2010, and the proportion of moderate and heavy S. mansoni infection was reduced from 15.6% in 2004 to 9.4% in 2010, both significantly (p<0.01). Mathematical modelling suggests that the observed results were in line with the expected changes.Conclusions/SignificanceSignificant reduction in intensity of infection on both infections and modest but significant reduction in S. haematobium prevalence were achieved in highly-endemic Segou region after repeated chemotherapy. However, persistent prevalence of both infections and relatively high level of intensity of S. mansoni infection suggest that more intensified control measures be implemented in order to achieve the goal of schistosomiasis elimination. In addition, closer monitoring and evaluation activities are needed in the programme to monitor the drug tolerance and to adjust treatment focus.

Functional immunogenicity of baculovirus expressing Pfs25, a human malaria transmission-blocking vaccine candidate antigen

We have focused on development of a novel vaccine vector based on “Baculophage”, a baculovirus display system for expression of proteins on the surface of the viral envelope, as a non-pathogenic and non-vertebrate insect virus. In the present study, recombinant baculovirus (AcNPV–Pfs25surf) were generated, which displayed Pfs25, a potent Plasmodium falciparum transmission-blocking vaccine candidate. Both intranasal and intramuscular immunizations of mice with AcNPV–Pfs25surf induced high levels of Pfs25-specific antibodies, which strongly reacted with ookinetes of transgenic Plasmodium berghei expressing Pfs25 (TrPfs25Pb). Importantly, sera obtained from immunized rabbits exhibited a significant transmission-blocking effect (>90% reduction in infection intensity) in standard membrane feeding assay using P. falciparum gametocytes. Additionally, active immunization (both intranasal and intramuscular routes) of mice followed by challenge using TrPfs25Pb demonstrated an effective transmission-blocking response, with an 83% (intranasal) and ∼95% (intramuscular) reduction in oocyst intensity, respectively. Thus, the baculovirus-based vaccines offer a promising new alternative to current human vaccine delivery platforms for the development of malaria multi-stage vaccines.

Intranasal and intramuscular immunization with Baculovirus Dual Expression System-based Pvs25 vaccine substantially blocks Plasmodium vivax transmission

We have recently developed a new experimental vaccine vector system based on Autographa californica nucleopolyhedrosis virus (AcNPV) termed the “Baculovirus Dual Expression System”, which drives expression of vaccine candidate antigens by a dual promoter that consists of tandemly arranged baculovirus-derived polyhedrin and mammalian-derived CMV promoters. The present study used this system to generate a Plasmodium vivax transmission-blocking immunogen (AcNPV-Dual-Pvs25). AcNPV-Dual-Pvs25 not only displayed Pvs25 on the AcNPV envelope, exhibiting aspects of its native three-dimensional structure, but also expressed appropriately immunogenic protein upon transduction of mammalian cells. Both intranasal and intramuscular immunization of mice with AcNPV-Dual-Pvs25 induced high Pvs25-specific antibody titres, notably of IgG1, IgG2a and IgG2b isotypes, indicating a mixed Th1/Th2 response. Importantly, sera obtained from subcutaneously immunized rabbits exhibited a significant transmission-blocking effect (96% reduction in infection intensity, 24% reduction in prevalence) when challenged with human blood infected with P. vivax gametocytes using the standard membrane feeding assay. Additionally, active immunization (both intranasal and intramuscular routes) of mice followed by challenge using a transgenic P. berghei line expressing Pvs25 in place of native Pbs25 and Pbs28 (clone Pvs25DR3) demonstrates a strong transmission-blocking response, with a 92.1% (intranasal) and 83.8% (intramuscular) reduction in oocyst intensity. Corresponding reductions in prevalence of infection were observed (88.4% and 75.5% respectively). This study offers a novel tool for the development of malarial transmission-blocking vaccines against the sexual stages of the parasite, using the Baculovirus Dual Expression System that functions as both a subunit, and DNA based vaccine.

The effect of single dose versus two doses of praziquantel on Schistosoma haematobium infection and pathology among school-aged children in Mali

The aim of this study was to assess the effect of two doses of 40 mg/kg praziquantel with 2 weeks interval versus a standard single dose of 40 mg/kg on cure rates, egg reduction, intensity of infection, and micro-haematuria in Schistosoma haematobium infections. A randomised controlled intervention study was carried out among school-aged children in two different endemic settings with follow-up at 3, 6 and 18 months following drug administration. Differences in cure rates between the two treatment regimens were not significant. However, in high transmission areas, the double treatment regimen was more effective in egg reduction than single treatment regimen and the difference in egg reduction between the two treatments was significant at 3 months (P<0.005), 6 months (P<0.0001) and 18 months (P<0.003) after treatment. There was a significant difference in the effect of the two treatments on prevalence of micro-haematuria at 18-month follow-up in both Koulikoro (P<0.001) and Selingue (P<0.003). The study shows that although no significant difference could be observed in the overall cure-rates between the two treatment regimens, the effect of double treatment was a significant reduction in infection intensity as well as micro-haematuria which may have a great impact in reducing subtle morbidity.

Hematodinium sp. in Irish Cancer pagurus fisheries: infection intensity as a potential fisheries management tool

Infection of Cancer pagurus by a parasitic dinoflagellate of the genus Hematodinium is described for the first time in Ireland. An industry-based monitoring programme was established to determine seasonality of infection intensity and prevalence in the country's 3 largest brown crab fisheries in the southwest, north and southeast. The parasite was present in all areas for the majority of sampling periods, with highest prevalences recorded in pre-recruit animals of both sexes. Microscopic examination of haemolymph revealed trophont, plasmodial and dinospore stages of the parasite. Overall prevalence in males (16%) was higher than in females (9%). Prevalence of Hematodinium sp. infection ranged from 0 to 51%, but a distinct seasonal trend was not apparent. Infection intensity was seasonal with significantly higher peaks occurring in late autumn/early winter months than in other quarters, corresponding to industry reports of moribund and dead pink-shelled crabs in commercial catches. We postulate that seawater temperature or a temperature-linked process is a key factor in triggering the final stages of infection, as significant autumn peaks were followed by a reduction in infection intensity as temperature decreased in the late winter/early spring months with no increase in intensity again until the following autumn. We propose that infection intensity, rather than prevalence, provides a more appropriate indication of the period when there is greatest potential for biological and economic impacts; the parameter's application as a fisheries management tool is discussed.

Efficacy of Pyrvinium Pamoate against Cryptosporidium parvum Infection In Vitro and in a Neonatal Mouse Model

No effective approved drug therapy exists for Cryptosporidium infection of immunocompromised patients. Here we investigated the nonabsorbed anthelmintic drug pyrvinium pamoate for inhibition of the growth of the intestinal protozoan parasite Cryptosporidium parvum. The concentration of pyrvinium that effected 50% growth inhibition in human enterocytic HCT-8 cells by a quantitative alkaline phosphatase immunoassay was 354 nM. For comparison, in the same assay, 50% growth inhibition was obtained with 711 microM paromomycin or 27 microM chloroquine. We used a neonatal mouse model to measure the anti-Cryptosporidium activity of pyrvinium pamoate in vivo. Beginning 3 days after infection, pyrvinium at 5 or 12.5 mg/kg of body weight/day was administered to the treatment group mice for 4 or 6 consecutive days. Nine days after infection, the mice were sacrificed, and drug efficacy was determined by comparing the numbers of oocysts in the fecal smears of treated versus untreated mice. The intensities of trophozoite infection in the ileocecal intestinal regions were also compared using hematoxylin-and-eosin-stained histological slides. We observed a >90% reduction in infection intensity in pyrvinium-treated mice relative to that in untreated controls, along with a substantial reduction in tissue pathology. Based on these results, pyrvinium pamoate is a potential drug candidate for the treatment of cryptosporidiosis in both immunocompetent and immunocompromised individuals.