Actual Infection Research Articles

E2 quasispecies specificity of hepatitis C virus association with allografts immediately after liver transplantation

It is unknown whether all hepatitis C virus (HCV) quasispecies variants found within patient serum have equal capacity to associate with the liver after transplantation; however, in vitro models of HCV infection suggest that variations in the hypervariable region 1 (HVR1) of the second envelope protein (E2) may be important in infectivity. The hypothesis of the current study is that the two hypervariable regions (HVR1 and HVR2) within E2 are important in the initial virus-liver interaction, and, therefore, certain HCV quasispecies variants will be isolated from the liver after reperfusion. In 8 patients with end-stage liver disease secondary to HCV infection, HCV envelope quasispecies were determined from intraoperative serum samples obtained before the anhepatic phase of transplantation and from liver biopsies 1.5 to 2.5 hours after the transplanted liver was perfused. Explanted (native) liver biopsies were taken as a control. Sequence analysis was performed on clones of specific HCV reverse transcriptase-polymerase chain reaction products spanning HVR1 and HVR2 of the E2 protein. HVR1 was more variable than HVR2 for all samples. Quasispecies isolated from postperfusion liver differed more from serum than did explanted liver quasispecies at HVR1 (P = 0.03) but not at HVR2 (P = 0.2). Comparison of HVR1 sequences from postperfusion liver versus serum revealed significantly less HVR1 genetic complexity and diversity (P = 0.02 and P = 0.04, respectively). Immediately after transplantation but before actual infection, liver allografts select out from the infecting serum inoculum a less heterogeneous, more closely related population of quasispecies variants.

Chronic hepatitis C virus infection established and maintained in chimpanzees independent of dendritic cell impairment

Chronic hepatitis C virus (HCV) infection in humans is associated with an impairment of dendritic cells (DC). It has been hypothesized that impairment of DC function may be a central mechanism facilitating the establishment of a chronic carrier state. However, the majority of patients studied with DC impairment to date have been identified and, thus, inadvertently selected because of clinical manifestations leading to their diagnosis, which may have been many years following actual infection. We set out to determine whether impaired DC function occurred in the earlier asymptomatic phase of infection and turned to a well-defined cohort of HCV-infected chimpanzees in which the specific date of infection and the nature of the inoculum were well characterized. Results revealed that, in contrast to the observations in human subjects with advanced clinical hepatitis, there was neither impairment of the allostimulatory capacity of monocyte-derived DC from HCV chronic carriers nor impairment of the maturation process. Decreased allostimulatory capacity was only detected in 2 animals and, interestingly, in those that possessed the highest viral loads. Nevertheless, HCV sequences were undetectable in any of the DC derived from HCV-infected chimpanzees. In conclusion, these findings suggest that the mechanisms of establishing persistent HCV infection are separate and independent from those responsible for impaired DC function. Indeed, the maturation and allostimulatory impairment, as described in patient studies, are not necessary prerequisites but rather possible consequences of persistent and active HCV infection associated with disease progression. (H epatology 2003;38:851-858.)

Parvovirus-B-19-assoziiertes hämophagozytisches Syndrom bei einer Patientin mit hereditärer Sphärozytose

Infections with parvovirus B 19 can cause aplastic crises with a rapid decline of hemoglobin levels in patients with hereditary spherocytosis. Usually, the symptoms and signs of the actual infection are mild. We here report on an eight year old girl with hereditary spherocytosis who was admitted to hospital with high temperature, headache, impaired consciousness and a profound anemia (Hb 2.9 mmol/l). Since she also developed low leukocyte and platelet counts a hematological malignancy was suspected. The bone marrow aspirate showed only 1 % erythroblasts and macrophages with active hemophagocytosis. The serum ferritin was 1381,4 ng/ml. Both, serology and PCR revealed an active infection with parvovirus B 19. Coagulation analysis suggested a low degree of disseminated intravasal coagulation (low fibrinogen, high D-dimers). We diagnosed a parvovirus B 19 associated hemophagocytic syndrome. With only symptomatic treatment the patient's condition and laboratory findings improved during the course of a few days. In accordance with other reported cases, the prognosis of parvovirus B 19 associated hemophagocytic syndrome seems to be better than in hemophagocytic syndrome of other origin.

Elevated Levels of Anti-Helicobacter pylori Antibodies in Henoch–Schönlein Purpura

Objective: Henoch–Schönlein purpura (HSP) is a systemic vasculitis characterized by IgA-containing deposits in the skin, joints, gastrointestinal mucosa and glomeruli. HSP is much rarer in adults than in children. Among a number of other pathogenic factors, Helicobacter pylori (Hp) has recently been implicated in the gastrointestinal and extra-gastrointestinal manifestations underlying HSP. We aimed at studying the occurrence of Hp infections in 11 adult HSP patients with appearance in our clinical practice in the last 5 years. Methods: Eleven adult HSP and 20 healthy adult patients were recruited for this study. Anti-Hp IgG and IgA antibodies were assessed in sera of HSP patients with active (n=5) and remittent disease (n=6) and healthy controls (n=20) in the context of clinical symptoms, endoscopic evaluation, as well as routine and immunolaboratory observations. Concurrent Hp infection was confirmed by urease test and histology. Results: Anti-Hp antibodies were present in 10/11 of HSP patients, and 11/20 of healthy controls. However, only 4/11 HSP patients had concurrent Hp infection as confirmed by urease test and/or histology. In the healthy controls the actual Hp infection was detectable in 9/20 cases. Patients in the acute phase had significantly higher levels of anti-Hp IgG compared to healthy controls (86.0±32.0 versus 25.5±28.5 U/ml, p<0.05). In contrast, anti-Hp IgA/IgG ratios were significantly higher in the remitting phase compared to the control group (3.1±1.8 versus 0.8±0.5 ratio, p<0.05). Among other immunolaboratory markers, serum CRP, circulating IgA and serum tumor necrosis factor-α levels were significantly increased in acute patients compared to healthy group results (45.3±22.7 versus 4.8±3.5 mg/l, p<0,05); (58.9±18.2 versus 25.2±6.4 pg/ml, p<0,05); (5.5±1.1 versus 2.4±1.2 g/l; respectively, p<0.05). Conclusions: Hp infection may be associated with the development and progression of HSP. IgG antibodies to Hp may be present mostly in acute HSP, while IgA antibodies may be involved in sustaining gastrointestinal symptoms underlying the chronic phase of the disease.

Changes in level of virus accumulation and incidence of infection are critical in the characterization of Rice tungro bacilliform virus (RTBV) resistance in rice.

Analysis by enzyme-linked immunosorbent assay showed that Rice tungro bacilliform virus (RTBV) accumulated in a cyclic pattern from early to late stages of infection in tungro-susceptible variety, Taichung Native 1 (TN1), and resistant variety, Balimau Putih, singly infected with RTBV or co-infected with RTBV + Rice tungro spherical virus (RTSV). These changes in virus accumulation resulted in differences in RTBV levels and incidence of infection. The virus levels were expressed relative to those of the susceptible variety and the incidence of infection was assessed at different weeks after inoculation. At a particular time point, RTBV levels in TN1 or Balimau Putih singly infected with RTBV were not significantly different from the virus level in plants co-infected with RTBV + RTSV. The relative RTBV levels in Balimau Putih either singly infected with RTBV or co-infected with RTBV + RTSV were significantly lower than those in TN1. The incidence of RTBV infection varied at different times in Balimau Putih but not in TN1, and to determine the actual infection, the number of plants that became infected at least once anytime during the 4 wk observation period was considered. Considering the changes in RTBV accumulation, new parameters for analyzing RTBV resistance were established. Based on these parameters, Balimau Putih was characterized having resistance to virus accumulation although the actual incidence of infection was >75%.

The nectary as the primary site of infection by Erwinia amylovora (Burr.) Winslow et al.: a mini review

Erwinia amylovora is the causative agent of fire blight, a bacterial disease existing as an unsolved problem in most countries where pome fruits like apple (Malus domestica) and pear (Pyrus communis) or ornamental plants of Rosaceae are grown. The primary site of colonization is the open flower. As for the establishment of the disease, the importance of various organs within the flowers is considerably different. The usual place for developing a large epiphytic population is the stigma. The actual infection will be attained by the external washing (rain, heavy dew) of bacteria from the stigma to the hypanthium. The bacteria penetrate through the openings of the nectary, so, the nectarthodes are the main entrance sites for them. Nectar is an excellent medium for growth of fire blight bacteria. Most often, however, the incidence of disease is significantly less than the percentage of colonized flowers. Little is known about the interrelationships of free mois- ture, nectar sugar concentration, ovary water potential, fine-structural characteristics of nectary versus the disease incidence and severity. The aim of this paper is to review the ecology and infection biology of Erwinia amylovora on floral surfaces and in floral tissues.

Natural alpha interferon-producing cells respond to human immunodeficiency virus type 1 with alpha interferon production and maturation into dendritic cells.

Natural alpha interferon (IFN-alpha)-producing cells (IPCs) are now recognized as identical to plasmacytoid dendritic cell (DC) precursors in human blood and are thought to play an important role in antiviral immunity. In the present study, we examined the susceptibility as well as the cellular responses of IPCs to human immunodeficiency virus type 1 (HIV-1) infection. HLA-DR(+) CD11c(-) lineage-negative cells (IPCs) were purified from peripheral blood mononuclear cells by magnetic-bead separation and cell sorting. We substantiated that IPCs expressing the major HIV-1 coreceptors, CXCR4 and CCR5, are susceptible to infection of both T-cell-line-tropic NL4-3 and macrophage-tropic JR-CSF HIV-1 by quantification of HIV-1 p24 in the culture supernatants and by provirus integration assay using human conserved Alu-HIV-1 long terminal repeat PCR. To evaluate the cellular response of IPCs to HIV-1, we examined IFN-alpha production and their differentiation into DCs. After incubation with either NL4-3 or JR-CSF, IPCs produced a large amount of IFN-alpha and at the same time underwent morphological differentiation into DCs with upregulation of CD80 and CD86. Heat inactivation of the supernatants containing HIV-1 did not affect the IFN-alpha production and maturation, whereas removal of virions by ultracentrifugation completely nullified both biological effects, indicating that these cellular responses do not require actual HIV-1 infection but are elicited by interaction with HIV-1 virions or certain viral components. In conclusion, these data strongly suggest that IPC can directly recognize and respond to HIV-1 with IFN-alpha production, which is crucial for preventing progress of HIV-1 infection and occurrence of opportunistic infection.

Screening Blood Donors at Risk for Malaria: Reply to Hänscheid et al.

Screening Blood Donors at Risk for Malaria: Reply to Hänscheid et al.

Needle-stick injuries in an Ugandan teaching hospital.

The on-going HIV epidemic has generally increased fear of needle-stick injuries (NSI) and renewed interest in the problem such injuries pose in Africa. The aims of the present study were to evaluate the frequency of NSI, explore the circumstances surrounding each injury and estimate the corresponding infection risk, among healthcare workers (HCW) in Uganda. Questionnaires, asking the recipients how many NSI they had suffered in the past year, how each of these NSI had occurred, what (perceived) risk of infection was associated with each injury, and what their practical and psychological reactions were, were sent to the HCW associated with the Mbarara Teaching Hospital in Uganda. Of the 280 individuals who received questionnaires, 180 (64%) responded and 100 (55% of the respondents) each reported suffering at least one NSI in the previous year. The total number of NSI reported (336) represented an incidence of 1.86 NSI/HCW-year. Interns suffered more NSI (annual mean=4.8) than any other occupational group. Most NSI occurred when patients moved during procedures, when HCW re-sheathed needles, or during suturing (each reported by 55 HCW--30% of those responding). Following NSI, 60 HCW said they squeezed the site of the injury and washed it with bleach, 43 believed they had a 10% risk of HIV infection, 87 felt anxious, 54 felt depressed, 40 prayed, 24 had an HIV test, and four were counselled. To estimate actual infection risk, 435 patients were screened for antibody to HIV (1 and 2) and for the surface antigen of the hepatitis B virus (HBSAg); 26% and 2.8% were found seropositive, respectively. These seroprevalences were multiplied by previously determined probabilities of transmission to give estimated risks of infection (following a single NSI) of 0.08% for HIV and 0.135% for hepatitis B. During 3 years of training as a clinician (i.e. 2 years as a medical student and 1 year as an intern), more than six in 1000 individuals would be infected with HIV as a result of NSI and almost 10 in 1000 would be infected with hepatitis B virus by the same route. NSI are common, preventable sources of infection and stress for HCW in Africa.

HIV-infected persons' knowledge of their sexual partners' HIV status.

The purpose of this study was to measure the accuracy of HIV-infected persons' knowledge of their sexual partners' HIV infection status. HIV-infected persons at two public health clinics reported their knowledge of the HIV infection status of their sexual partners. Actual HIV test results for sexual partners were then linked to survey responses. The association between reported knowledge and actual infection status of partners was estimated by kappa scores and percent agreement. Sixty-four percent (14/22) of partners thought to be infected were actually uninfected, and 42% (8/19) of partners thought to be uninfected were actually infected. The overall percent agreement was 46% (kappa = -0.06), less than that expected by random chance alone. Individuals in committed partnerships were less likely to have accurate knowledge than those in casual partnerships. In conclusion, HIV-infected individuals have poor knowledge regarding their partners' infection status. This may influence sexual behaviors that result in increased transmission.

Hepatitis B surface antigenemia in chronic hemodialysis patients: effect of hepatitis B immunization.

Hemodialysis patients with hepatitis B surface antigen (HBsAg) are considered to have the hepatitis B virus (HBV) and are segregated to limit transmission. However, transient de novo HBsAg has been identified in hemodialysis patients shortly after vaccination. Our hypothesis is that immunization rather than actual HBV infection is the most common cause of de novo HBsAg among hemodialysis patients. We performed a prospective study between January, 1998 and June, 2000 of de novo HBV infection in over 2400 hemodialysis patients who were screened monthly for HBsAg using a standard enzyme immunoassay. Positive results were confirmed with a neutralization assay. If the confirmatory test was positive, anti-hepatitis B core antibody IgM testing was performed. We identified nine patients with de novo HBsAg confirmed with the neutralization assay. In eight of the nine patients with de novo HBsAg (89%), HBsAg was temporally related to HBV immunization. In none of these eight patients was there a detectable anti-hepatitis B core antibody IgM, an elevated ALT level, or clinical history suggestive of recent hepatitis. The mean age (+/- SD) of the four men and four women was 56.4 +/- 18.8 yr. HBsAg was detectable within 3 days of immunization in most patients. Our results suggest that HBV immunization is the most common cause of detectable HBsAg in hemodialysis patients. Hemodialysis patients should not be screened for HBV within a week of immunization, and caution should be exercised when interpreting HBsAg seropositivity within 4 wk of HBV immunization.

Hepatitis B surface antigenemia in chronic hemodialysis patients: effect of hepatitis B immunization

OBJECTIVE: Hemodialysis patients with hepatitis B surface antigen (HBsAg) are considered to have the hepatitis B virus (HBV) and are segregated to limit transmission. However, transient de novo HBsAg has been identified in hemodialysis patients shortly after vaccination. Our hypothesis is that immunization rather than actual HBV infection is the most common cause of de novo HBsAg among hemodialysis patients. METHODS: We performed a prospective study between January, 1998 and June, 2000 of de novo HBV infection in over 2400 hemodialysis patients who were screened monthly for HBsAg using a standard enzyme immunoassay. Positive results were confirmed with a neutralization assay. If the confirmatory test was positive, anti-hepatitis B core antibody IgM testing was performed. RESULTS: We identified nine patients with de novo HBsAg confirmed with the neutralization assay. In eight of the nine patients with de novo HBsAg (89%), HBsAg was temporally related to HBV immunization. In none of these eight patients was there a detectable anti-hepatitis B core antibody IgM, an elevated ALT level, or clinical history suggestive of recent hepatitis. The mean age (± SD) of the four men and four women was 56.4 ± 18.8 yr. HBsAg was detectable within 3 days of immunization in most patients. CONCLUSION: Our results suggest that HBV immunization is the most common cause of detectable HBsAg in hemodialysis patients. Hemodialysis patients should not be screened for HBV within a week of immunization, and caution should be exercised when interpreting HBsAg seropositivity within 4 wk of HBV immunization.

Dengue virus replicative intermediate RNA detection by reverse transcription-PCR.

Dengue virus replication involves synthesis of a replicative intermediate RNA (RI-RNA), whose presence reveals an actual infection. We report on a simple and rapid reverse transcription-PCR for the detection of viral RI-RNA in infected cells. The product is demonstrated at 20 min postinfection. This method is useful for the study of virus-cell tropism.

Rhinovirus elicits proasthmatic changes in airway responsiveness independently of viral infection

Background: Rhinovirus (RV), the principal pathogen responsible for the common cold, is importantly implicated in triggering attacks of asthma secondary to changes in airway responsiveness. Objective: Because the airway histopathologic features of RV infection are relatively modest, we tested the hypothesis that RV can directly elicit proasthmatic-like changes in airway smooth muscle (ASM) responsiveness independently of actual viral infection and its associated cytopathic effects. Methods: Isolated ASM tissues and cultured ASM cells were inoculated with either infectious or noninfectious (UV-irradiated) RV16 and RV2, the latter serotypes belonging to the “major” and “minor” groups of RV subtypes, respectively. ASM constrictor and relaxant responsiveness, Gi protein expression, and proinflammatory cytokine release were subsequently compared under the different treatment conditions. Results: In contrast to RV2, which had no effect, RV16 inoculation elicited enhanced ASM contractility and impaired relaxation to cholinergic and β-adrenergic agonists, respectively, in association with increased ASM membrane Gi protein expression and induced release of the proinflammatory cytokines IL-5 and IL-1β. These proasthmatic-like effects were also observed in ASM exposed to UV-irradiated RV16, wherein viral replication was completely inhibited. In contrast, pretreatment of ASM with a neutralizing antibody directed against ICAM-1, the host receptor for the “major” group of RVs, completely abrogated the proasthmatic effects of RV16. Conclusions: The results demonstrate that (1) RV16 elicits proasthmatic changes in ASM responsiveness that can occur independently of actual viral infection of the ASM and (2) the effects of RV16 are attributed solely to binding of the virus to its host receptor (ICAM-1) on the ASM cell surface. Collectively, these findings support the notion that RV-induced exacerbation of wheezing in asthmatic individuals can occur even in the absence of any cytopathology associated with viral infection. (J Allergy Clin Immunol 2001;108:997-1004.)

Quantitative culture of bronchoalveolar lavage fluid in community-acquired lower respiratory tract infections

To evaluate the diagnostic value of quantitative bacterial culture of bronchoalveolar lavage (BAL) fluid obtained by fibreoptic bronchoscopy, 67 consecutive immunocompetent adult patients admitted to hospital with community-acquired lower respiratory tract infections from September 1997 to May 1998 were investigated. Results were compared to the findings in eight healthy control persons investigated in February 1998. There was no difference between study patients and control persons when quantitative culture of total cumulative bacterial findings or bacteria categorized as members of the oropharyngeal normal flora were compared. The culture of normal flora in bronchial washings probably reflects contamination of the lower airways with secretions from upper airways by the fibreoptic procedure itself, as fractionated sampling showed a 10-fold reduction in quantitative culture results when a primary bronchial washing was compared to a secondary sampling from the same bronchus in the control group. Twenty-four (36%) of 67 patients were cultured as positive in the study group while all control persons were cultured as negative for bacteria categorized as potential pathogens. With a threshold value for positive culture of 104cfu ml−1the specificity of lavage culture of potential pathogenic bacteria in relation to actual lower airway infection was 100%. Therefore, quantitative bacterial culture of potential pathogenic bacteria in BAL fluid is very specific but only positive in about one-third of unselected immunocompetent adult patients with a lower respiratory tract infection.

Anticonvulsant Hypersensitivity Syndrome

Anticonvulsant hypersensitivity syndrome (AHS) is a serious but poorly understood and little known disease. It has been variously described in the literature since 1934. Fatalities are rare but have been reported.A MEDLINE search was undertaken from 1991 to present, using the keywords "anticonvulsant," "phenytoin," and "hypersensitivity." English language articles and their endnotes were reviewed, and neurologists, dermatologists, and specialists in hematology-oncology were consulted.A case of AHS is described. Investigators have reported epidemiologic data and described the pathophysiology, diagnostic criteria, and management options.Family physicians should be aware of the AHS because of the high likelihood that patients with this syndrome will come first to their primary care physicians for care. Certain anticonvulsant medications have a high degree of cross-reactivity, the incidence of AHS is higher among first-degree relatives, and the disorder mimics systemic infection. If AHS is suspected, the antiepileptic drug should be discontinued. Supportive care should be directed to the appropriate organ systems, with particular attention to skin, eyes, and liver. Corticosteroid treatment might be effective in reversing the drug reactions, but it is not recommended in cases of suspected or actual infection because of the increased risk of immunocompromise, sepsis, and associated mortality.

Effects of Metarhizium anisopliae on the pollen beetle Meligethes aeneus and its parasitoids Phradis morionellus and Diospilus capito

The efficacy of two Finnish strains of Metarhizium anisopliaeagainst the rape blossom beetle Meligethes aeneus (Coleoptera:Nitidulidae) and the effect on its parasitoids Phradismorionellus (Hymenoptera: Ichneumonidae) and Diospilus capito(Hymenoptera: Braconidae) were studied in laboratory and semi-fieldexperiments. Several bio-assays were performed using either directexposure of the host beetle to the pathogens, or pots containing soilinoculated with M. anisopliae conidia at a rate of 2 ×108 per ml soil. Parasitised and unparasitised M. aeneuslarvae were collected in the field and were placed for pupation in thetest soil. The effect of treatment on M. aeneus andD. capito was estimated after adult emergence, and the effecton P. morionellus was estimated by dissecting hibernating pupae.While both of the M. anisopliae strains were highly pathogenicto M. aeneus adults and larvae upon direct exposure, soiltreatment resulted in no significant difference between the number ofinsects emerging (or found) from the treated and untreatedpots. However, the treated insects appeared to be latently infectedand the actual infection rate had to be estimated after their deathand incubation in a moist chamber. The mortality of the beetles causedby direct exposure to the fungus was 85% (range 70–88%). The rateof latent infection following indirect exposure via treated soil indeep pots in laboratory was 80% (range 49–100%), while that inP. morionellus was only 17% (range 0–85%), and inD. capito significantly higher, 76% (range 72–100%).The results indicate that M. anisopliae is a potentially usefulcandidate to be used as a bio-insecticide to control the pollenbeetle, and that at least the most abundant parasitoid, Phradismorionellus, is less affected than the target pest itself. Thepossible ecological role of latent infections in the host as well asin some of the parasitoids needs to be clarified.

Diagnosis of canine echinococcosis: comparison of coproantigen detection with necropsy in stray dogs and red foxes from northern Jordan.

The sandwich enzyme linked immunosorbent assay (ELISA) was used as a diagnostic test for Echinococcus granulosus infection by detecting coproantigens in 94 stray dogs Canis familiaris and eight red foxes (Vulpes vulpes) from northern Jordan. The results were analyzed in relation to actual helminth infection as revealed by necropsy. The infection rate of dogs with E. granulosus was 13.8% with a worm load ranging between 3-> 10,000 per infected dog. In contrast, eight of 13 E. granulosus infected dogs were coproantigen positive (overall sensitivity 61.5%). The sensitivity increased to 87.5% and 100% in dogs harboring > 20 and > 100 worms/dog, respectively. The specificity of coproantigen-ELISA was 91%. The greatest cross-reactivity was found in dogs infected with Dipylidium caninum. The positive and negative predictive values for the coproantigen-ELISA test were 50% and 94.2%, respectively. Thus, a coproantigen negative dog is most probably truly negative for E. granulosus. In contrast, a coproantigen positive dog may not be truly positive for E. granulosus, except if it has a high worm burden of > 100 worms/animal.

Application of a polymerase chain reaction-ELISA to detect Wuchereria bancrofti in pools of wild-caught Anopheles punctulatus in a filariasis control area in Papua New Guinea.

Chemotherapy-based eradication programs are aimed at stopping transmission of Wuchereria bancrofti by its obligatory mosquito vector. This study compares one year post-treatment W. bancrofti infection rates of Anopheles punctulatus, the main vector of lymphatic filariasis in Papua New Guinea, using traditional dissection techniques and a polymerase chain reaction (PCR)-based ELISA of a parasite-specific Ssp I repeat. A total of 633 mosquitoes in 35 batches were dissected. Six batches contained W. bancrofti-infected mosquitoes, giving a minimum infection rate of 0.9%. This value was not different than the actual infection rate, which was 9 (1.4%) of 633 mosquitoes (P = 0.48). The DNA was extracted from 47 pools containing a mean of 13.2 mosquitoes per pool. A total of 621 mosquitoes were processed for the PCR-ELISA, including 486 caught by human bait and 135 by light trap, which included both dead and live mosquitoes. Of 23 pools of alcohol-preserved human-bait mosquitoes, seven were positive by the PCR-ELISA, giving an infection rate identical to that obtained by dissection of individual mosquitoes (1.4%). The minimum infection rates for pools of light-trap mosquitoes found dead and alive were 2.7% (2 of 74) and 4.9% (3 of 61), respectively. These values did not differ from each other (P = 0.84), but the overall infection rate of light-trap mosquitoes was greater than that of mosquitoes captured by human bait (3.7% versus 1.4%; P = 0.09). These data indicate that the PCR-ELISA of a W. bancrofti Ssp I repeat using pools of mosquitoes is comparable to traditional dissection techniques for monitoring transmission intensity following introduction of mass chemotherapy. This approach may also be useful for rapid and cost-effective assessment of transmission in endemic areas where the frequency of overt lymphatic pathology is low.

Stone risk after bladder substitution with the ileal-urethral Kock reservoir.

The study was carried out to compare urinary biochemical and physicochemical environments in patients who had undergone bladder substitution with the ileal-urethral Kock reservoir, and who had no actual urinary infection, with those of healthy subjects. The participants were 23 male patients who had undergone bladder substitution with the ileal-urethral Kock reservoir and 25 healthy men. All subjects had sterile urine at the time of urine collection. Concentrations of calcium, magnesium, phosphorus, creatinine, citrate, oxalate, and ammonia in 24-h urine samples were measured. Estimates of ion activity products of calcium oxalate (CaOx), calcium phosphate (CaP), brushite (Bru), and magnesium ammonium phosphate (MAP) in urine were calculated according to Tiselius. There was no significant difference in 24-h urinary volume between patients with a bladder substitute and the healthy controls. For most of the other measured values the results for patients differed significantly from those for controls. The most striking findings were markedly lower urinary excretion rates of citrate (p < 0.0001) and higher urine pH (p < 0.0001) in patients compared with controls. These findings were reflected in significantly higher levels of urinary supersaturation with respect to CaOx (p < 0.0001), CaP (p <0.0001), Bru (p < 0.0001) and MAP (stuvite) (p < 0.0001) in patients with a bladder substitute compared with healthy subjects. Hypocitraturia seems to be the main risk factor for calcium stone formation in non-infected Kock reservoir patients, and citrate supplementation appears to be the most obvious choice for stone prophylaxis in patients with intestinal urinary diversion and recurrent renal stone formation.