A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log₁₀ increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence.

High Treatment Uptake in Human Immunodeficiency Virus/Hepatitis C Virus-Coinfected Patients After Unrestricted Access to Direct-Acting Antivirals in the Netherlands

Background

The Netherlands has provided unrestricted access to direct-acting antivirals (DAAs) since November 2015. We analyzed the nationwide hepatitis C virus (HCV) treatment uptake among patients coinfected with human immunodeficiency virus (HIV) and HCV.

Methods

Data were obtained from the ATHENA HIV observational cohort in which >98% of HIV-infected patients ever registered since 1998 are included. Patients were included if they ever had 1 positive HCV RNA result, did not have spontaneous clearance, and were known to still be in care. Treatment uptake and outcome were assessed. When patients were treated more than once, data were included from only the most recent treatment episode. Data were updated until February 2017. In addition, each treatment center was queried in April 2017 for a data update on DAA treatment and achieved sustained virological response.

Results

Of 23574 HIV-infected patients ever linked to care, 1471 HCV-coinfected patients (69% men who have sex with men, 15% persons who [formerly] injected drugs, and 15% with another HIV transmission route) fulfilled the inclusion criteria. Of these, 87% (1284 of 1471) had ever initiated HCV treatment between 2000 and 2017, 76% (1124 of 1471) had their HCV infection cured; DAA treatment results were pending in 6% (92 of 1471). Among men who have sex with men, 83% (844 of 1022) had their HCV infection cured, and DAA treatment results were pending in 6% (66 of 1022). Overall, 187 patients had never initiated treatment, DAAs had failed in 14, and a pegylated interferon-alfa-based regimen had failed in 54.

Conclusions

Fifteen months after unrestricted DAA availability the majority of HIV/HCV-coinfected patients in the Netherlands have their HCV infection cured (76%) or are awaiting DAA treatment results (6%). This rapid treatment scale-up may contribute to future HCV elimination among these patients.

Soluble TLR2 and 4 concentrations in cerebrospinal fluid in HIV/SIV-related neuropathological conditions

HIV in the central nervous system (CNS) mainly infects microglial cells which are known to express toll-like receptors (TLRs). This paper aimed to study the role of soluble TLR2 (sTLR2), sTLR4, and other inflammatory markers in cerebrospinal fluid (CSF) in HIV/Simian immunodeficiency virus (SIV)-related neurological sequelae. We determined sTLR2 and sTLR4 levels in CSF and serum/plasma of SIV-infected rhesus macaques with and without neurological sequelae, as well as in HIV-infected patients with and without cognitive impairments and Alzheimer's disease (AD) patients and matched controls. CSF cytokines and chemokines levels were analyzed in macaques as markers of neuroinflammation, while neopterin and S100B CSF concentrations were measured in HIV-infected patients as microglial and astrocyte marker, respectively. We found detectable levels of sTLR2 and sTLR4 in CSF of macaques and humans. Furthermore, CSF sTLR2 and sTLR4 concentrations were higher in SIV-infected macaques with neurological sequelae compared to those without neurological complications (p = 0.0003 and p = 0.0006, respectively). CSF IL-8 and monocyte chemoattractant protein-1 (MCP-1) levels were elevated in macaques with neurological sequelae, and a positive correlation was found between CSF levels of sTLR2/4 and IL-8 and MCP-1. Also in humans, elevated CSF sTLR4 levels were found in HIV-infected patients with cognitive impairments compared to HIV-infected patients with normal cognition (p = 0.019). Unlike CSF S100B levels, neopterin correlated positively with sTLR2 and sTLR4. No difference was found in plasma and CSF sTLR2 and sTLR4 levels between AD patients and control subjects (p = 0.26). In conclusion, CSF sTLR2 and sTLR4 may play a role in HIV/SIV-related neuroinflammation and subsequent neuropathology.

The diagnostic accuracy of serological tests for Lyme borreliosis in Europe: a systematic review and meta-analysis

Background

Interpretation of serological assays in Lyme borreliosis requires an understanding of the clinical indications and the limitations of the currently available tests. We therefore systematically reviewed the accuracy of serological tests for the diagnosis of Lyme borreliosis in Europe.

Methods

We searched EMBASE en MEDLINE and contacted experts. Studies evaluating the diagnostic accuracy of serological assays for Lyme borreliosis in Europe were eligible. Study selection and data-extraction were done by two authors independently. We assessed study quality using the QUADAS-2 checklist. We used a hierarchical summary ROC meta-regression method for the meta-analyses. Potential sources of heterogeneity were test-type, commercial or in-house, Ig-type, antigen type and study quality. These were added as covariates to the model, to assess their effect on test accuracy.

Results

Seventy-eight studies evaluating an Enzyme-Linked ImmunoSorbent assay (ELISA) or an immunoblot assay against a reference standard of clinical criteria were included. None of the studies had low risk of bias for all QUADAS-2 domains. Sensitivity was highly heterogeneous, with summary estimates: erythema migrans 50 % (95 % CI 40 % to 61 %); neuroborreliosis 77 % (95 % CI 67 % to 85 %); acrodermatitis chronica atrophicans 97 % (95 % CI 94 % to 99 %); unspecified Lyme borreliosis 73 % (95 % CI 53 % to 87 %). Specificity was around 95 % in studies with healthy controls, but around 80 % in cross-sectional studies. Two-tiered algorithms or antibody indices did not outperform single test approaches.

Conclusions

The observed heterogeneity and risk of bias complicate the extrapolation of our results to clinical practice. The usefulness of the serological tests for Lyme disease depends on the pre-test probability and subsequent predictive values in the setting where the tests are being used. Future diagnostic accuracy studies should be prospectively planned cross-sectional studies, done in settings where the test will be used in practice.

Reduced PTLD-related mortality in patients experiencing EBV infection following allo-SCT after the introduction of a protocol incorporating pre-emptive rituximab

The mortality associated with post-transplant lymphoproliferative disorder (PTLD) induced by EBV infection can be reduced by monitoring EBV by polymerase-chain-reaction and rituximab given pre-emptively. We performed a retrospective analysis of the risk factors for the occurrence of EBV infection/disease and EBV-related mortality among 273 consecutive recipients of a T-cell-depleted allo-SCT during two periods: (a) before the implementation of a comprehensive protocol (2006-2008) and (b) afterwards (2009-2011). EBV infection was detected in 61 (22%) cases, and 28 cases were considered to have had EBV disease. Treatment with antithymocyte globulin was the most important risk factor (odds ratio (OR) 2.4; 95% confidence interval (CI) 1.3-4.2, P=0.001). After implementation of the protocol, in patients experiencing EBV infection, pre-emptive therapy was started more often and sooner (median 3 vs 6 days, P=0.002). Moreover, there were fewer cases of monomorphic PTLD (4/33 (12%) vs 11/28 (39%), P=0.01), and the EBV-related mortality was lower for patients experiencing EBV infection (2/33 (6%) vs 8/28 (29%), OR 0.2; 95% CI 0.05-0.9, P=0.03). The EBV protocol proved feasible and resulted in faster initiation of pre-emptive therapy, the diagnosis in an earlier stage of EBV disease, and decreased EBV-related mortality.

Toll-like receptors and microbial exposure: gene-gene and gene-environment interaction in the development of atopy

Environmental and genetic factors contribute to atopy development. High microbial exposure may confer a protective effect on atopy. Toll-like receptors (TLRs) bind microbial products and are important in activating the immune system. To assess whether interactions between microbial exposures and genes encoding TLRs (and related genes) result in atopy, genes, environmental factors and gene-environment interactions of 66 single-nucleotide polymorphisms (SNPs) of 12 genes (TLR 1-6, 9 and 10, CD14, MD2, lipopolysaccharide-binding protein (LBP) and Dectin-1), and six proxy parameters of microbial exposure (sibship size, pets (three different parameters), day-care and intrauterine and childhood tobacco smoke exposure) were analysed for association with atopic phenotypes in 3,062 Dutch children (the Allergenic study). The presence of two or more older siblings increased the risk of developing high total immunoglobulin (Ig)E levels at different ages. This risk increased further in children aged 1-2 yrs carrying the minor allele of TLR6 SNP rs1039559. Furthermore, novel two- and three-factor gene-gene and gene-environment interactions were found (e.g. between sibship size, day-care and LBP SNP rs2232596). Larger sibship size is associated with increased total IgE levels. Furthermore, complex two- and three-factor interactions exist between genes and the environment. The TLRs and related genes interact with proxy parameters of high microbial exposure in atopy development.

X-chromosome Forkhead Box P3 polymorphisms associate with atopy in girls in three Dutch birth cohorts

BACKGROUND

The Forkhead Box P3 (FOXP3) gene, located on the X-chromosome, encodes a transcription factor that directs T cells toward a regulatory phenotype. Regulatory T cells may suppress development of atopy. We evaluated whether single-nucleotide polymorphisms (SNPs) of FOXP3 are associated with atopy development in childhood.

METHODS

Seven SNPs in FOXP3 were genotyped in 3062 children (51% boys) participating in the Allergenic study, which consists of three Dutch birth cohorts (PIAMA, PREVASC and KOALA). Association of FOXP3 SNPs with total serum IgE and sensitisation (presence of specific serum IgE to egg, milk, and indoor, i.e. house-dust mite, cat, and/or dog allergens) was investigated at ages 1, 2, 4, and 8. Analysis of variance and logistic regression were performed, stratified for gender.

RESULTS

Our most consistent finding was observed for sensitisation to egg and indoor allergens. In girls, five FOXP3 SNPs (rs5906761, rs2294021, rs2294019, rs6609857 and rs3761548) were significantly associated with sensitisation to egg at ages 1 and 2 and with sensitisation to indoor allergens at age 2 (P < 0.05), but not at 4 and 8, a finding that was observed across the three cohorts. Rs5906761 and rs2294021 were associated with remission of sensitisation to food allergens in boys, as tested in the PIAMA cohort.

CONCLUSION

This is the first study showing across three cohorts that X-chromosomal FOXP3 genotypes may contribute to development of sensitisation against egg and indoor allergens in girls in early childhood. In addition, an association with remission of sensitisation to food allergens existed in boys only.

TLR-related pathway analysis: novel gene-gene interactions in the development of asthma and atopy

BACKGROUND

The toll-like receptor (TLR)-related pathway is important in host defence and may be crucial in the development of asthma and atopy. Numerous studies have shown associations of TLR-related pathway genes with asthma and atopy phenotypes. So far it has not been investigated whether gene-gene interactions in this pathway contribute to atopy and asthma development.

METHODS

One hundred and sixty-nine haplotype tagging single nucleotide polymorphisms (SNPs) of 29 genes (i.e. membrane and intracellular receptors, TLR4 or lipopolysaccharide-binding/facilitating proteins, adaptors, interleukin-1 receptor associated kinases, kinases, chaperone molecules, transcription factors and inhibitors) were analysed for single- and multilocus associations with atopy [total and specific immunglobulin E (IgE) at 1-2 and 6-8 years] and asthma (6-8 years). A total of 3062 Dutch children from the birth cohorts PIAMA, PREVASC and KOALA (Allergenic study) were investigated. Chi-squared test, logistic regression and the data mining approach multifactor dimensionality reduction method (MDR) were used in analysis.

RESULTS

Several genes in the TLR-related pathway were associated with atopy and/or asthma [e.g. IL1RL1, BPI, NOD1, NOD2 and MAP3K7IP1]. Multiple, single associations were found with the phenotypes under study. MDR analysis showed novel, significant gene-gene interactions in association with atopy and asthma phenotypes (e.g. IL1RL1 and TLR4 with sIgE to indoor allergens and IRAK1, NOD1 and MAP3K7IP1 with asthma). Interestingly, gene-gene interactions were identified with SNPs that did not have an effect on their own.

CONCLUSION

Our unbiased approach provided suggestive evidence for interaction between several TLR-related pathway genes important in atopy and/or asthma development and pointed to novel genes.

Interaction of T-cell and antigen presenting cell co-stimulatory genes in childhood IgE

It is likely that multiple genes contribute to immunoglobulin (Ig)E production. Co-stimulatory molecules are crucial for the cross-talk between antigen presenting cells and T-lymphocytes which drives the IgE response. We evaluated gene-gene interactions of haplotype tagging polymorphisms in a pathway of 24 co-stimulatory genes in relation to serum IgE levels. We assessed this at ages 1-2 yrs and 6-8 yrs in 3,062 Dutch children from a pooled data set of three birth cohorts: PIAMA (Prevention and Incidence Asthma and Mite Allergy), PREVASC (Prevention of Asthma in Children) and KOALA (Child, parents and health: lifestyle and genetic constitution). Single- and multi-locus associations with serum IgE levels (3rd versus 1st tertile) were evaluated by Chi-squared tests and the multifactor dimensionality reduction (MDR) method in the following co-stimulatory genes: VTCN1, TNFRSF4, TNFRSF18, TNFRSF14, TNFSF18, TNFSF4, CD28, CTLA4, ICOS, PDCD1, BTLA, CD80, CD86, HLA-G, CD274, PDCD1LG2, CD276, LILRA4, LILRB1, LILRB2, LILRB4, CD40, ICOSLG, and CD40LG. We found multiple statistically significant single-locus ((S)) and multi-locus ((M)) associations for the genes VTCN1(SM), TNFSF18(SM), TNFSF4(S), CD28(S), CTLA4(M), ICOS(S), BTLA(M), CD80(M), CD86(SM), CD274(SM), PDCD1LG2(M), LILRA4(SM), LILRB4(M), and CD40(SM) with serum IgE. Two-locus interactions of CD86 with VTCN1 and CD274 with LILRA4 were confirmed by logistic regression. In conclusion, serum IgE levels are regulated by multiple gene-gene interaction effects in the co-stimulatory pathway. We suggest using research strategies that model multiple gene-gene interactions in genetic studies.

Occupational risk of human Cytomegalovirus and Parvovirus B19 infection in female day care personnel in the Netherlands; a study based on seroprevalence

Cytomegalovirus (CMV) and Parvovirus B19 infections acquired during pregnancy may result in developmental disabilities of the foetus. This study evaluates the occupational risk of these infections in female day care personnel. IgG seroprevalence was determined in 310 Dutch day care workers and 158 nursing school students. CMV seroprevalence was age-related, starting at 21% in those <20 years and reaching 65% in those >35 years. Between the ages of 20 and 24 years the CMV prevalence was higher in day care personnel than in controls, 50% versus 31% (p = 0.03). In the first 2 years of employment the risk of attracting CMV was significantly increased (OR(adj) = 3.80; p < 0.001) and the occupational risk was also increased (OR(adj) 2.19; p < 0.001). Parvovirus seropositivity (71-77%) was not related to age or working at a day care centre. In conclusion, an occupational risk was observed for CMV, but not for Parvovirus infection in female day care personnel.

Interleukin 13, CD14, pet and tobacco smoke influence atopy in three Dutch cohorts: the allergenic study

Studying gene-environment interactions may elucidate the complex origins of atopic diseases but requires large study populations. Pooling data from several cohort studies may help but may also obscure findings. Gene-environment interactions in atopy development were studied and the benefits of pooling data were evaluated. Haplotype-tagging polymorphisms in the genes interleukin (IL)13 and CD14 were genotyped in 3,062 children from the following birth cohorts: the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) study; the Prevention of Asthma in Children (PREVASC) study; and the Child, Parent, Health, Focus on Lifestyle and Predisposition (KOALA) study, and tested for association with total and specific immunoglobulin (Ig)E and interaction with tobacco smoke and pet exposure at ages 1, 2, 4 and 8 yrs by analysis of variance, Chi-squared tests and regression analyses. At all ages, in IL13, minor alleles of rs1295685 and rs20541 were significantly associated with elevated IgE levels in pooled analyses. In CD14, the rs2569190-TT and rs2569191-CC genotypes associated with lower IgE and decreased risk of sensitisation at 4 and 8 yrs in children exposed to pets, with an opposite effect in nonexposed children. Findings for IL13 and CD14 were comparable in separate cohorts. The present study indicates that atopy is importantly influenced by interleukin 13 at age 1-8 yrs and by CD14 in interaction with pet exposure at ages 4 and 8 yrs. Additionally, pooled data improved effect estimates and genetic effects could be detected in interaction with important environmental factors.

Cytokines and soluble CD14 in breast milk in relation with atopic manifestations in mother and infant (KOALA Study)

BACKGROUND

Conflicting evidence exists concerning the protective role of breastfeeding in allergy and atopic disease aetiology. Breast milk contains biologically active molecules influencing the innate immune system of newborns.

OBJECTIVE

We aim to assess whether cytokines (TGF-beta1, IL-10 and IL-12) and soluble CD14 (sCD14) in breast milk are influenced by maternal atopic constitution and modify the development of atopic manifestations in infants.

METHODS

Milk samples were collected at 1 month post-partum of 315 lactating mothers participating in the ongoing KOALA Birth Cohort Study. The cytokines and sCD14 were analysed by ELISA in the aqueous fraction. We compared the concentrations of cytokines and sCD14 in breast milk between mothers with and without an allergic history and also with and without allergic sensitization (specific IgE). Associations of cytokines and sCD14 with the development of eczema, wheezing in the first 2 years of life and allergic sensitization of infants at the age of 2 years were analysed by multivariate logistic regression analyses to correct for confounders.

RESULTS

We found higher sCD14 levels in mothers with a positive vs. negative allergic history (7.6 vs. 7.0 microg/mL; P = 0.04) and in mothers who were sensitized vs. non-sensitized (7.8 vs. 7.1 microg/mL; P = 0.03). None of the studied immune factors were associated with infant's atopic outcomes. IL-10 was not detected above the detection limit of 0.2 pg/mL.

CONCLUSION

Taking together the results of the present and previous studies, we conclude that there is no convincing evidence for a relation between TGF-beta1, sCD14, IL-10 or IL-12 in breast milk and atopic manifestations in infants.

Influence of SERTPR and STin2 in the serotonin transporter gene on the effect of selective serotonin reuptake inhibitors in depression: a systematic review

Large differences in clinical response to selective serotonin reuptake inhibitors (SSRIs) are observed in depressive patients with different genotypes. Quantification of these differences is needed to decide if genetic testing prior to antidepressant treatment is useful. We conducted a systematic review of the literature on the influence of polymorphisms in the serotonin transporter gene (SERTPR (or 5-HTTLPR) and STin2) on SSRI response. Studies were identified by the use of MEDLINE, EmBase and PsycINFO, references of articles, reviews and information from pharmaceutical companies. Nine studies assessing the influence of SERTPR or STin2 on treatment response were included. Outcome was expressed as the percentage of decrease in depression score (HAM-D or MADRS) or as the percentage of responders (> or =50% reduction on the depression scale). Both study methodologies and study outcomes showed large heterogeneity. Weighted mean decreases in depression score for patients with the s/s, s/l and l/l genotypes were 35.4, 46.3 and 48.0% at week 4, respectively, and 53.9, 54.6 and 48.3% at week 6. Among Caucasian patients, both mean decrease in depression score and response rate were lowest in the s/s group, while among Asian patients, results were inconsistent. Weighted response rates were 36.1% for the 10/12 genotype of the STin2 polymorphism and 80.7% for the 12/12 genotype (chi2=27.8, P<0.001) (only Asians). The available evidence points to a less favourable response to SSRI treatment among Caucasian patients with the SERTPR s/s genotype and among (Asian) patients with the STin2 10/12 genotype. In view of the scarcity and heterogeneity of the studies, however, current information is insufficiently reliable as a basis for implementing genetic testing in the diagnostic work-up of the depressive patient.

Evaluation of the patterns of Schistosoma mansoni infection and re-infection in Senegal, from faecal egg counts and serum concentrations of circulating anodic antigen

Infection and re-infection patterns were evaluated in a recent Schistosoma mansoni focus in northern Senegal, by determining concentrations of serum circulating anodic antigen (CAA), as a measure of worm burden, and counting eggs in faeces before, 6 or 12 weeks and 1 year after praziquantel treatment in two subsequent cohorts (cohort A and B). No differences in egg counts and CAA concentrations or their relationship were found between the cohorts, which were examined 2 years apart. Within both cohorts, CAA concentrations showed the same, typical, age-related patterns as egg counts, with a peak in children and a strong decline in adults. These trends were apparent both before and 1 year after treatment. The results indicate that an age-related resistance to infection and to re-infection has been firmly established, at a steady level, in the recent S. mansoni focus investigated, with no indication of a gradual development of immunity or anti-fecundity immunity over a period of 2 years. Both shortly and 1 year after treatment, the decrease in egg counts was stronger than that in CAA concentrations, indicating that that there had been a reduction in worm fecundity after treatment. The possibility that praziquantel may induce anti-fecundity immunity has important implications for the use and interpretation of the results of (egg-count-based) re-infection studies designed to follow the development of naturally acquired immunity.

Are poor responses to praziquantel for the treatment of Schistosoma mansoni infections in Senegal due to resistance? An overview of the evidence

This paper summarizes and concludes in-depth field investigations on suspected resistance of Schistosoma mansoni to praziquantel in northern Senegal. Praziquantel at 40 mg/kg usually cures 70-90% of S. mansoni infections. In an initial trial in an epidemic S. mansoni focus in northern Senegal, only 18% of the cases became parasitologically negative 12 weeks after treatment, although the reduction in mean egg counts was within normal ranges (86%). Among other hypotheses to explain the observed low cure rate in this focus, the possibility of drug resistance or tolerance had to be considered. Subsequent field trials with a shorter follow-up period (6-8 weeks) yielded cure rates of 31-36%. Increasing the dose to 2 x 30 mg/kg did not significantly improve cure rates, whereas treatment with oxamniquine at 20 mg/kg resulted in a normal cure rate of 79%. The efficacy of praziquantel in this focus could be related to age and pre-treatment intensity but not to other host factors, including immune profiles and water contact patterns. Treatment with praziquantel of individuals from the area residing temporarily in an urban region with no transmission, and re-treatment after 3 weeks of non-cured individuals within the area resulted in normal cure rates (78-88%). The application of an epidemiological model taking into account the relation between egg counts and actual worm numbers indicated that the low cure rates in this Senegalese focus could be explained by assuming a 90% worm reduction after treatment with praziquantel; in average endemic situations, such a drug efficacy would result in normal cure rates. Laboratory studies by others on the presence or absence of praziquantel resistance in Senegalese schistosome strains have so far been inconclusive. We conclude that there is no convincing evidence for praziquantel-resistant S. mansoni in Senegal, and that the low cure rates can be attributed to high initial worm loads and intense transmission in this area.

Dynamics of egg counts and circulating antigen levels in a recent Schistosoma mansoni focus in northern Senegal

Serum circulating anodic antigen (CAA) levels were compared with faecal egg counts in four subsequent population samples, randomly selected at 8-month intervals, in a recent Schistosoma mansoni focus in northern Senegal. In all four samples, antigen levels showed the same age-intensity profiles as egg counts, with a strong decline in adults. Also across population samples, a consistent relationship was found between egg counts and antigen levels. Assuming the level of CAA to be a direct reflection of worm burden, these findings support the idea that the observed egg count patterns and levels indeed reflect dynamics of worm burdens, and not of egg excretion or worm fecundity. Remarkably similar levels of both egg counts and CAA were observed in the first and last sample, collected in the same season (August--September), but 2 years apart. This suggests that a steady state of S. mansoni infection had already been reached shortly after the onset of the epidemic in this focus (3 years). Significantly lower infection levels were found in the intermediate population samples collected in January and April. The differences in infection levels across the four population samples may be because of seasonal transmission patterns. They would indicate a substantial turnover of worm populations, with an estimated average life span of only 7 months, probably less, in this recently emerged, intense S. mansoni focus.

The contribution of host-related factors to low cure rates of praziquantel for the treatment of Schistosoma mansoni in Senegal

Surprisingly low cure rates were repeatedly observed after treatment with a standard dosage of praziquantel in a recently established Schistosoma mansoni focus in northern Senegal. In 4 discrete cohorts from the same population, cure rates were 18-36% and egg count reduction rates were 77-88%. Data and material of 920 compliant subjects from all 4 cohorts were further analyzed to identify possible host-related factors associated with low cure rates. The lowest cure rates were found in the highest egg count groups. However, in low and moderate egg count groups, drug efficacy was also below normal values. Cure rates were similar in males and females, showed no seasonal variation, and were independent of previous praziquantel treatment. They were significantly higher in adults than in children, also after allowing for intensity of infection. Individual water contact behavior and specific humoral immune responses were examined in 2 extreme subgroups, either without significant egg count reduction or showing complete parasitologic cure. There was no significant difference in frequency and duration of water contact between those individuals with complete cure and those that showed little effect of praziquantel treatment. Levels of IgG, IgG1, IgG3, IgG4, IgM, and IgE against adult worm antigen were not different between the 2 subgroups. Thus, the abnormally frequent failure of treatment observed in this focus could not be associated with any host-related factor, other than age and pretreatment egg counts.

Serum circulating egg antigen levels in two areas endemic for Schistosoma mansoni

A monoclonal antibody-based enzyme-linked immunosorbent assay detecting Schistosoma mansoni circulating soluble egg antigen (CSEA) was applied in epidemiological studies. The serum CSEA levels were determined for 2 populations with a high prevalence (> 95%) and high intensity of infection as determined by faecal egg counts. In one population (Maniema, Zaire) transmission had been occurring for several decades, while in the other population (Ndombo, Senegal) transmission had started only recently. CSEA could be detected in 88% and 70% of the serum samples from Maniema and Ndombo, respectively. The sensitivity of the CSEA assay increased with rising egg count. The age-related CSEA profiles of the Maniema population followed a pattern similar to that of egg counts and of the adult worm antigen CAA (circulating anodic antigen). However, the recently infected Ndombo population showed a clearly different profile: while the CSEA prevalence reached a peak in children and adolescents, the mean CSEA levels did not vary significantly in the different age groups. CSEA levels were significantly lower in Ndombo than in Maniema. As egg antigens in serum are thought to be in part, or even primarily, derived from eggs in the tissues, these findings indicate a relatively smaller tissue egg load in Ndombo than in Maniema.

Evaluation of ultrasonographic staging systems for the assessment of Schistosoma mansoni induced hepatic involvement

For the sonographic assessment and grading of hepatosplenic morbidity induced by Schistosoma mansoni infection, several quantitative and qualitative classification systems have been used. In an attempt to evaluate two staging systems, a study was performed as part of a schistosomiasis research and control programme in Richard Toll, Senegal. A total of 700 residents of the township N'diangué were parasitologically, clinically and sonographically examined in July 1993. Two ultrasound observers (M.D. and E.D.) applied the Cairo and the Managil classification (E.D. only) for the grading of periportal thickening of the liver. In spite of high prevalence and intensity of infection, severe hepatic morbidity was rare. According to the Cairo classification, there was a high percentage of subjects with grade I periportal thickening, with considerable inter-observer variability. In the Cairo classification, which is based on the diameter of peripheral portal vein branches, firm cut-offs are used, independent of body height. We show the relationship between body height and portal vein diameters and recommend the use of body height-dependent reference values to avoid falsely high percentages of periportal thickening, especially in children. To minimize inter-observer variability, a clarification of existing instructions for taking measurements for grading is suggested. These suggestions have been considered during the follow-up expert meeting on the Cairo classification in Niamey under the auspices of the World Health Organization in October 1996.

Organometric investigations of the spleen and liver by ultrasound in Schistosoma mansoni endemic and nonendemic villages in Senegal

With the intention of ultrasonographically assessing hepatosplenic morbidity in Schistosoma mansoni infection and of validating the grading system applied (Cairo classification), 191 subjects in a schistosomiasis endemic village and 247 controls from a nonendemic village in northern Senegal underwent sonographic examination of the liver and spleen. Measurements of the diameters of the peripheral periportal vein branches, the main portal vein stem, liver size (left lobe and right lobe), and spleen length in the endemic village were compared with those in the nonendemic village to evaluate the much discussed influence of S. mansoni infection on those variables. To subtract this presumed influence from reference values for the named variables, they are given as measured in the nonendemic village, stratified by body weight, enabling future investigators on schistosomiasis-induced morbidity to refer to these reference values. The 95th percentile regarding peripheral periportal vein branch diameter in the control groups was exceeded in 24% of the subjects in the endemic group. It was exceeded by 6% for the main portal vein stem diameter, 13% for the left liver lobe, 12% for the right liver lobe, and 14% for the spleen length. According to the Cairo classification, 97% of the endemic population and 81% of the controls had periportal thickening of the liver, mostly grade I. We conclude that 1) hepatic morbidity in the S. mansoni endemic area was low, despite strikingly high intensities of infection; 2) the Cairo classification in its present form overestimates periportal thickening, especially in the case of mild morbidity; and 3) body height-dependent reference values, obtained from endemic controls, must be applied for organometric parameters.

Oxamniquine cures Schistosoma mansoni infection in a focus in which cure rates with praziquantel are unusually low

An outbreak of Schistosoma mansoni in northern Senegal was observed in 1988, and chemotherapy with praziquantel in this recently established focus resulted in very low parasitologic cure rates. Among other explanations, the emergence of a praziquantel-tolerant parasite strain was feared. To study this hypothesis further, 138 persons with endemic S. mansoni infection were randomly allocated to treatment with either 20 mg/kg oxamniquine or 40 mg/kg praziquantel. Parasitologic cure rates at 6 weeks were significantly higher in the oxamniquine group (79%) compared with those in the praziquantel group (36%; P = .0043). The reduction in egg counts was generally good, but 12% less reduced in the praziquantel group. These results confirm that cure rates with praziquantel were abnormally low, whereas oxamniquine performed satisfactorily, as in other areas in which S. mansoni is endemic. The possibility of a praziquantel-tolerant S. mansoni strain must therefore be studied carefully.

Therapeutic evaluation of two different dose regimens of praziquantel in a recent Schistosoma mansoni focus in Northern Senegal

A therapeutic trial, involving 130 Schistosoma mansoni-infected children, with no previous history of antischistosomal treatment, was carried out to evaluate the efficacy of two different dose regimens of praziquantel. The study was carried out because low cure rates were described in this recently established (1990) S. mansoni focus in northern Senegal, following treatment with a standard dosage of 40 mg/kg. The subjects were randomly allocated into two groups: one group (1) received 40 mg/kg in one oral dose, the other group (2) was treated with two oral doses of 30 mg/kg at a 6-hr interval. Parasitologic examination and circulating anodic antigen (CAA) detection were performed before, 10 days, three, six, and 21 weeks after chemotherapy. No significant differences in cure rates were found between the two groups. Six weeks after treatment, 34% and 44% of the individuals were found to be stool negative in group 1 and group 2, respectively. However, only 10-15% became completely negative according to the serum CAA antigen assay. Mean egg counts were reduced by 99% in both groups. Antigen detection confirmed the parasitologic results. Fewer side effects were observed in the group treated with 2 x 30 mg/kg, which may be explained by split dosage administration. Our study shows that the low cure rates observed in this area could not be improved by using a higher dosage of praziquantel.

Ultrasonography in a Senegalese community recently exposed to Schistosoma mansoni infection

Inhabitants of Ndombo (n = 614), a village in an area recently infected with Schistosoma mansoni in Northern Senegal, were examined clinically, parasitologically, and ultrasonographically to investigate the presence and degree of S. mansoni-related hepatosplenic morbidity after a few years of exposure to schistosomal infection of regional canals. Despite previous praziquantel treatment of 56% of the inhabitants prior to our investigation, the prevalence of S. mansoni infection in 1993 was 90%, and 42% of the villagers excreted more than 1,000 eggs per gram of stool. Previously untreated individuals were found to have significantly higher egg counts than treated ones. Despite the high intensities of infection, ultrasonographically detected severe periportal thickening of the liver was infrequent. Grading according to body length-dependent normal values of cross-section diameter of peripheral portal vein branches of a European control group correlated with intensities of infection. Of the total group of patients, 30% (n = 182) had more severe thickening of portal vein branch diameters above the 97th percentile and 70% of these had a splenomegaly. The highest egg counts and the most frequent development of periportal thickening were found in 11-20 year-old individuals. Periportal thickening was less frequent in praziquantel-treated adolescents than in untreated ones. This suggests that early antischistosomal medication may be useful to limit schistosomiasis-induced hepatic morbidity especially in children, even though reinfection seems inevitable.

Antibody response patterns against Schistosoma mansoni in a recently exposed community in Senegal

Acquired immune resistance is believed to be largely responsible for age-dependent infection and reinfection patterns in schistosomiasis. In a recently established but intense focus of Schistosoma mansoni in Senegal, the humoral immune response was studied in a random population sample of 289. Antibody levels of various isotypes to schistosome worm and egg antigens were determined by ELISA and related to egg counts (eggs per gram of feces [EPG]), age, and sex. Both IgG1 and IgG4 followed age-related patterns similar to egg counts and strongly correlated with EPG, even after allowing for age. Specific IgE levels increased slowly with age. The humoral immune response patterns in this recently infected population appeared to be largely similar to those in chronically infected communities. Thus far, the observations do not support the current hypothesis that age-related resistance to Schistosoma is determined by IgE-mediated protective immunity acquired during many years of exposure.

Efficacy and side effects of praziquantel in an epidemic focus of Schistosoma mansoni

Schistosoma mansoni was first reported in the area of Richard Toll (Senegal) in 1988 and spread rapidly in the community, after a series of human-engineered ecologic changes. A random population sample (n = 422) from Ndombo, a village near Richard-Toll, was studied in 1991 by stool examination (four Kato slides from two stool samples) and antigen detection in urine and blood. Stool-positive individuals were treated with 40 mg/kg of praziquantel. A house-to-house interview regarding side effects was conducted 24 hr after treatment. Two hundred ninety-eight subjects were re-examined 10 days (antigen detection) and 12 weeks (egg counts, antigen detection) after treatment. Before treatment, positive egg counts were found in 91% of the subjects, with 41% excreting more than 1,000 eggs per gram (epg) of feces. Treatment of 352 individuals caused serious but transient side effects (colic, vomiting, urticaria, and edema), the frequency of which increased with increasing egg counts. The parasitologic cure rate 12 weeks after treatment was only 18%, the frequency of egg counts with more than 1,000 epg decreased to 5%, and the mean egg count of those remaining positive was reduced by 86%. Antigen detection in serum 10 days and 12 weeks after treatment remained positive in 90% of the subjects, although titers decreased sharply. The low cure rates may be due to intense transmission and/or undeveloped immune responses in this recently exposed population. However, reduced drug susceptibility of the parasite strain has now been confirmed in one local isolate.

Epidemiologic application of circulating antigen detection in a recent Schistosoma mansoni focus in northern Senegal

Quantitative enzyme-linked immunosorbent assays (ELISAs) for the detection of circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) in serum and urine were applied as an epidemiologic tool in a recent, intense focus of Schistosoma mansoni in Senegal. Both CAA and CCA in serum and CCA in urine were found in 94%, 83%, and 95%, respectively, of the population, of which 91% were positive on stool examination. Circulating antigens were also detectable in sera and urines of most egg-negative individuals. The sensitivities of the urine CCA and serum CAA ELISA were substantially higher than that of a single egg count, and increased with egg output. The CAA and CCA levels correlated well with egg counts and with each other. The age-related evolution of antigen levels followed a similar pattern as egg counts, providing supplementary evidence for a genuine reduction of worm burdens in adults in spite of the supposed absence of acquired immunity in this recently exposed community. The antigen:egg ratios decreased in adults, suggesting lower worm fecundity in children. This would be compatible with a density-dependent reduction of fecundity, but not with anti-fecundity immunity in adults that perhaps has not yet developed in this new focus.

Morbidity due to heavy Schistosoma mansoni infections in a recently established focus in northern Senegal

A study of morbidity due to Schistosoma mansoni infection was carried out in Ndombo, a recently established but intense focus in northern Senegal. A random population sample (n = 422) was examined by repeated egg counts, standardized interviews, and clinical examinations. Egg counts were positive in 91%, with more than 1,000 eggs per gram of feces in 41% of the subjects. Abdominal discomfort was reported by 60% of the subjects, diarrhea by 33%; 17% of the stools were liquid upon inspection. Hepatomegaly was mostly mild and found in 7% of the subjects, mainly in males less than 20 years of age. Splenomegaly was detected in only 0.5% of the people examined. There was no significant correlation between the frequency of complaints or symptoms and egg counts. The remarkably mild morbidity in spite of the intense level of many infections may be explained by the recent nature of the focus; more severe chronic morbidity may develop in the future.

Epidemiology of Schistosoma mansoni infection in a recently exposed community in northern Senegal

The epidemiology of Schistosoma mansoni infection was investigated in Ndombo, a village in the epicenter of a very recent outbreak of schistosomiasis in northern Senegal. Repeated fecal egg counts and antigen detection in urine and serum were carried out in a random population sample (n = 422). Eggs were found in 91% of the subjects, with 41% excreting > 1,000 eggs per gram of feces (epg) (mean egg load of 646 epg). The prevalence was almost 100% in groups greater than five years of age. In spite of the supposed absence of acquired immunity, intensities of infection decreased strongly in adults. Antigen detection confirmed the high prevalence and intensity of infection and the age-related distribution of worm loads. The emergence of this new focus is probably due to the ecologic impact of newly built dams and the extension of irrigation projects in the Senegal basin.