bluuebunny/crossref_metadata_2025 huggingface dataset:
Seroprevalence of hepatitis E virus among United Nations Mission in Haiti (UNMIH) peacekeepers, 1995.
Authors: Gambel J M , Drabick J J , Seriwatana J , Innis B L
Published: May 2017

Information about the prevalence of hepatitis E virus (HEV) infection is sparse in many countries. Following the identification of four cases of acute HEV infection among Bangladeshi soldiers, a serologic survey was conducted to determine the prevalence of HEV infection among other peacekeepers from the United Nations Mission in Haiti (UNMIH) and Haitian civilians. Of the 981 participants in the survey, 876 were soldiers from eight UNMIH-participating countries representing Asia, Africa, and the Americas, and 105 were Haitian civilians. The prevalence of HEV infection by country (from highest to lowest) included Pakistan (62%), India (37%), Nepal (37%), Bangladesh (27%), Djibouti (13%), Honduras (6%), Guatemala (5%), Haiti (3%), and the United States (2%). More than 90% of those surveyed from Guatemala, Haiti, and Honduras, where prevalence data has been scarce, appeared susceptible to HEV infection. Future multinational missions like the UNMIH might also present unique opportunities to study health threats of widespread interest.
Diversity of Babesia infecting deer ticks (Ixodes dammini).
Authors: Armstrong P M , Katavolos P , Caporale D A , Smith R P , Spielman A , Telford S R
Published: May 2017

To determine whether the presence of nonpathogenic piroplasms may confound field estimates of risk of Babesia microti infection, we identified sporozoites infecting the salivary glands of deer ticks (Ixodes dammini) by parallel microscopy and polymerase chain reaction assays. Piroplasms were evident in 14.4% of adult ticks from sites in the northcentral and northeastern United States. Of these, 83.3% contained DNA characteristic of Ba. odocoilei. This cervid piroplasm was detected in all of the sites examined and generally was more prevalent than was Ba. microti. Because deer ticks transmit both Ba. odocoilei and Ba. microti, estimates of pathogen prevalence based solely on microscopy may overestimate the risk of human babesiosis.
Brazilian isolates of Trypanosoma cruzi from humans and triatomines classified into two lineages using mini-exon and ribosomal RNA sequences.
Authors: Fernandes O , Souto R P , Castro J A , Pereira J B , Fernandes N C , Junqueira A C , Naiff R D , Barrett T V , Degrave W , Zingales B , Campbell D A , Coura J R
Published: May 2017

Traditional molecular and biochemical methods, such as schizodeme analysis, karyotyping, DNA fingerprinting, and enzyme electrophoretic profiles, have shown a large variability among Trypanosoma cruzi isolates. In contrast to those results, polymerase chain reaction (PCR) amplification of sequences from the 24S alpha ribosomal RNA gene and from the mini-exon gene nontranscribed spacer indicated a dimorphism among T. cruzi isolates, which enabled the definition of two major parasite lineages. In the present study, 86 T. cruzi field stocks (68 isolated from humans with defined presentations of Chagas' disease and 18 from triatomines) derived from four Brazilian geographic areas were typed by the PCR assay based on the DNA sequences of the mini-exon and 24S alpha rRNA genes. These stocks were ordered into the two major T. cruzi lineages. Lineage 1 was associated mainly with human isolates and lineage 2 with the sylvatic cycle of the parasite.
Natural polymorphism in the thrombospondin-related adhesive protein of Plasmodium falciparum.
Authors: Robson K J , Dolo A , Hackford I R , Doumbo O , Richards M B , Keita M M , Sidibe T , Bosman A , Modiano D , Crisanti A
Published: May 2017

We have developed a typing system using natural sequence variation in the thrombospondin-related adhesive protein (TRAP) gene of Plasmodium falciparum. This method permits a haplotype to be assigned to any particular TRAP gene. We have applied this method to a hospital-based, case control-study in Mali. Previous sequence variation and conservation in TRAP has been confirmed. Particular TRAP haplotypes can be used as geographic hallmarks. Because of the high level of conflict between characters, we have examined the phylogenetic relationships between parasites using a network approach. Having received patient samples from urban and periurban areas of Bamako, the majority of haplotypes were closely related and distinct from TRAP sequences present in other continents. This suggests that the structure of TRAP can only tolerate a limited number of sequence variations to preserve its function but that this is sufficient to allow the parasite to evade the host's immune system until a long-lived immune response can be maintained. It may also reflect host genetics in that certain variants may escape the host immune response more efficiently than others. For vaccine design, sequences from the major regional variants may need to be considered in the production of effective subunit vaccines.
Day-to-day fluctuation of schistosome circulating antigen levels in serum and urine of humans infected with Schistosoma mansoni in Burundi.
Authors: Polman K , Engels D , Fathers L , Deelder A M , Gryseels B
Published: May 2017

Day-to-day fluctuations of both circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) in serum and urine were examined simultaneously in a group of Schistosoma mansoni-infected individuals from Burundi and compared with each other and with fecal egg count fluctuations. Significant correlations were found between fecal egg counts and circulating antigens (CAA and CCA) and between circulating antigen levels in serum and urine samples. The cumulative percentage of positive results after three samplings was highest for urine CCA detection, followed by fecal egg counts, serum CCA, serum CAA, and urine CAA detection, respectively. It was demonstrated that circulating antigen levels in both serum and urine showed less fluctuation than fecal egg counts, except for urine CAA levels. The serum CAA detection assay in particular, although less sensitive in this low endemic area in Burundi, gave very constant measurements over a period of one week. Our results indicate that detection of circulating antigens in a single serum or urine sample provides a quantitatively more stable diagnosis of S. mansoni infection than fecal egg counts based on a single stool examination.
Studies on the Plasmodium vivax relapse pattern in Delhi, India.
Authors: Adak T , Sharma V P , Orlov V S
Published: May 2017

A five-year epidemiologic study of patients attending a malaria clinic in Delhi was conducted to find the relapse rate of infections with Plasmodium vivax, its seasonal correlation between the primary infection and subsequent relapses, the duration of the incubation period, and the patterns of relapse. By our definition, the relapse rate ranged from 23% to 44% depending on the duration of follow-up. The relapse pattern observed in the study clearly suggests the existence of both tropical and temperate zone types of P. vivax in the population characterized by distinct incubation periods and the possible existence of P. vivax subpopulations characterized by primary long incubation periods. The implication of different incubating forms of P. vivax on the epidemiology and control of malaria is also discussed.
A study of antibody and T cell recognition of rhoptry-associated protein-1 (RAP-1) and RAP-2 recombinant proteins and peptides of Plasmodium falciparum in migrants and residents of the state of Rondonia, Brazil.
Authors: Jacobson K C , Thurman J , Schmidt C M , Rickel E , Oliviera de Ferreira J , Ferreira-da-Cruz M F , Daniel-Ribeiro C T , Howard R F
Published: May 2017

Humoral and cellular responses were examined among natives and migrants in an area of the Amazon region of Brazil. Rhoptry-associated protein-1 (RAP-1) and RAP-2 expressed in Escherichia coli expression systems, a peptide corresponding to the epitope bound by inhibitory anti-RAP-1 antibodies, and four other RAP-1 and RAP-2 synthetic peptides were used in these studies. Plasma from the native population had greater IgG reactivity to the N-terminal third of RAP-1 than the migrant population; both populations had low levels of IgM to this region of RAP-1. The IgG reactivity to RAP-2 and to the C-terminal third of RAP-1, as well as for all the peptides, including the peptide from the inhibitory domain, were low or absent in both populations. In contrast, there were a high number of subjects with an IgM response to the peptides. Cellular responses were measured by proliferation of peripheral blood mononuclear cells (PBMC) and, in some subjects, by reverse transcription-polymerase chain reaction for interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-4, and IL-10. Proliferation of PBMC was low when stimulated by recombinant proteins, peptides, or parasite lysate. Both RAP-1 and RAP-2 stimulated cytokine production by donor T cells; IL-2, IL-4, and IFN-gamma RNA transcripts were observed in response to recombinant proteins and parasite lysate, but with no uniform trends. From the observed antibody responses, RAP-1 appears to be more immunogenic than RAP-2.
Hepatitis E virus infection in eastern India.
Authors: Bansal J , He J , Yarbough P O , Sen S , Constantine N T , Sen D
Published: May 2017

Most cases of enterically transmitted non-A, non-B hepatitis in India have so far been attributed to hepatitis E virus (HEV) infection. Most of the documented studies of hepatitis have focused on the incidence of this disease in northern, western, and south central India. A small seroprevalence study was conducted in the eastern Indian city of Patna to assess the degree of HEV infection among acute sporadic hepatitis cases. Forty-two percent (24 of 57) of the cases of acute sporadic hepatitis were positive for anti-HEV antibodies. Absence of any serologic markers of hepatitis A, B, or E in 58% (33 of 57) of the cases with symptoms of acute hepatitis suggest that there may be as yet unidentified enterically transmitted viruses in this area.
Cystatin capture enzyme-linked immunosorbent assay for immunodiagnosis of human paragonimiasis and fascioliasis.
Authors: Ikeda T
Published: May 2017

An ELISA was developed using chicken cystatin as a capture agent for the immunodiagnosis of paragonimiasis and fascioliasis. The assay detected specific antibodies to fluke cysteine proteinases without the need for purified proteinases. An ELISA plate was sensitized with chicken egg white cystatin, incubated with excretory-secretory (ES) products of adult flukes, and standard ELISA procedures were then followed. The ELISA plates incubated with the ES products of Paragonimus westermani and Fasciola sp. showed high reactivity to sera from patients with paragonimiasis westermani and fascioliasis, respectively. The capture ELISA showed little cross-reactivity with sera from patients with paragonimiasis and fascioliasis, which showed immunodiagnostic cross-reactivity in a conventional ELISA using crude fluke antigens. Moreover, the capture ELISA showed little reactivity with sera from patients with five other helminth diseases and from healthy volunteers. Omitting either sensitization with cystatin or incubation with fluke ES products abolished high ELISA reactivity, as did a prior exposure of the ES products to cystatin. The addition of papain to an incubation solution of the ES products greatly reduced ELISA reactivity. Incubating the cystatin-sensitized plates with partially purified cysteine proteinases from flukes instead of the ES products also maintained a similar high ELISA reactivity. These results indicate that the cystatin capture ELISA elicits a cystatin and fluke cysteine proteinase antigen-mediated reaction and measures fluke cysteine proteinase-specific antibodies. Prior exposure to low molecular weight inhibitors of cysteine proteinases and other proteinases, such as E-64, leupeptin, aprotinin, and pepstatin, had no effect, suggesting that these inhibitors can be added to cysteine proteinase preparations to prevent autoproteolysis. This assay has good sensitivity and high specificity and is useful for the immunodiagnosis of paragonimiasis and fascioliasis.
Studies on schistosomiasis in western Kenya: II. Efficacy of praziquantel for treatment of schistosomiasis in persons coinfected with human immunodeficiency virus-1.
Authors: Karanja D M , Boyer A E , Strand M , Colley D G , Nahlen B L , Ouma J H , Secor W E
Published: May 2017

Praziquantel is the drug of choice for schistosomiasis chemotherapy. Although the exact mechanism of how praziquantel kills schistosomes remains poorly understood, the immune response of the host is an important factor in drug efficacy. It is thus possible that disease states of humans that lead to immunodeficiencies, such as infection with human immunodeficiency virus-1 (HIV-1), may render praziquantel less effective in treating schistosomiasis. To test this hypothesis, persons with high levels of Schistosoma mansoni infection who were or were not also infected with HIV-1 were treated with a standard regimen of praziquantel and monitored by quantitative fecal examination and plasma circulating cathodic antigen. Both groups responded to praziquantel therapy equally and individuals with low percentages (< 20%) of CD4+ T cells did not differ from individuals with higher CD4 cell percentages. These data demonstrate that persons with HIV-1 infection can be treated effectively for schistosomiasis with praziquantel.
Geographic distribution and clinical description of leishmaniasis cases in Peru.
Authors: Lucas C M , Franke E D , Cachay M I , Tejada A , Cruz M E , Kreutzer R D , Barker D C , McCann S H , Watts D M
Published: May 2017

Studies were conducted from 1986 through 1993 to further define the geographic distribution and relative importance of different species of Leishmania as a cause of leishmaniasis in Peru. Patients with a clinical diagnosis of cutaneous and/or mucosal or diffuse cutaneous leishmaniasis were enrolled at the Naval Medical Research Institute Detachment (NAMRID) Laboratory in Lima, the Tropical Disease Clinic at San Marcos University Daniel A. CarriÃ³n, the Central Military Hospital, and a Ministry of Health hospital in Cusco, Peru. Clinical features, lesion aspirates, and biopsy tissue were obtained from each patient. All specimens were collected and assayed separately, including multiple specimens from some of the same patients for Leishmania parasites by inoculating aliquots of either aspirates or biopsy tissue suspensions onto Senekji's blood agar medium. Stocks of Leishmania isolates were used to prepare promastigotes to produce extracts for identifying the Leishmania species by the cellulose acetate electrophoresis enzyme technique. A total of 351 isolates of Leishmania were obtained from 350 patients who were infected primarily in the low and high jungle of at least 15 different Departments of Peru. Of the 351 isolates, 79% were identified as L. (V.) braziliensis, 7% as L. (V.) guyanensis, 10% as L. (V.) peruviana, 2% as L. (V.) lainsoni, and 1.7% as L. (L.) amazonensis. The clinical form of disease varied depending on the species of Leishmania, with L. (V.) braziliensis being associated most frequently with cutaneous, mucosal ulcers and mixed cutaneous and mucosal disease, and L. (V) peruviana, L. (V.) guyanensis, L. (V.) lainsoni with cutaneous lesions. Leishmania (L.) amazonensis was isolated from six patients, three with cutaneous lesions, one with mucosal lesions, and two with diffuse cutaneous lesions. Among all of the leishmaniasis cases, males were affected more frequently, and cases occurred among patients less than 10 to more than 51 years of age. These data further defined the geographic distribution and the relative frequency of Leishmania species associated with different clinical forms of leishmaniasis in Peru.
Short report: The safety and toxicity of insect repellents.
Authors: Goodyer L , Behrens R H
Published: May 2017

In recent years, concerns have been raised regarding the safety of diethyltoluamide (DEET), one of the most widely used and reliable insect repellents available. This paper summarizes the recent evidence and concludes that concerns over safety appear largely unfounded.
Reduction of Culiseta melanura fitness by eastern equine encephalomyelitis virus.
Authors: Scott T W , Lorenz L H
Published: May 2017

The traditional view of interactions between arboviruses and their arthropod vectors is that vector hosts become increasingly resistant to parasites; parasite attenuation occurs; or through the process of coevolution, resistance and attenuation occur in concert. Detrimental effects from arboviruses are only seen when vector and virus are not yet well adapted. Results from this study indicate that eastern equine encephalomyelitis (EEE) virus reduces survival and reproduction (fitness) of the mosquito Culiseta melanura, which is required for transmission of EEE virus in North America. Mosquito virulence was not measurably attenuated in virus isolates recovered 55 year apart. This virus did not affect the ability of mosquitoes to obtain a blood meal or the rate of mosquito oocyte development. Results from this study support those from earlier investigations with other mosquito-virus interactions and suggest that reproductively successful arboviruses can have detrimental effects on their mosquito vectors.
The public health significance of urinary schistosomiasis as a cause of morbidity in two districts in Mali.
Authors: Traore M , Traore H A , Kardorff R , Diarra A , Landoure A , Vester U , Doehring E , Bradley D J
Published: May 2017

Schistosoma haematobium-related morbidity was studied in the perennial irrigation area of Office du Niger and the small reservoirs area of Plateau Dogon in Mali. Questionnaire, clinical, parasitologic, and ultrasound examination data were collected from 1,041 individuals at the baseline survey in 1991; 705 were re-examined one year after treatment. At baseline, the overall prevalence of S. haematobium infection was 55.2%; half of those infected had no clinical symptoms and 30% had pathologic lesions. Both infection and morbidity were more frequent in children than in adults, with a peak prevalence at 7-14 years of age. The rates of lesions were more than twice as high in those heavily infected as in lightly infected individuals. Reagent strip testing for microhematuria was more sensitive in detecting individuals with pathologic lesions than in detecting individuals with infection. One year after treatment with praziquantel, more than 80% of the urinary tract lesions had cleared. It is concluded that S. haematobium-related morbidity is frequent in Mali, but passive case detection for treatment would not cover a great deal of early stages of the disease; active intervention using reagent strip testing for microhematuria at the most peripheral levels would be an efficient system for morbidity control and monitoring of control operations.
Anti-leishmanial IgE antibodies: a marker of active disease in visceral leishmaniasis.
Authors: Atta A M , D'Oliveira  , Correa J , Atta M L , Almeida R P , Carvalho E M
Published: May 2017

Visceral leishmaniasis (VL) is characterized by a depression of the T helper cell type 1 immune response. Although mRNA expression for interleukin-4 (IL-4) is observed, evidence of the role of this cytokine in the pathogenesis of VL has been lacking. Since IL-4 is involved in IgE synthesis, we measured the total IgE and Leishmania antigen-specific IgE antibody levels in sera from patients with VL. Specific IgE antibodies detected by an ELISA technique after absorbing the sera with purified sheep IgG anti-human IgG were found in all 23 patients with VL and were not detected in subjects with subclinical Leishmania chagasi infection (n = 10), Chagas' disease (n = 10), atopic patients (n = 10), and healthy controls (n = 10). Levels of Leishmania-specific IgE (optical density values) before and after treatment were 0.100 +/- 0.03 (mean +/- SD) and 0.028 +/- 0.002, respectively (P < 0.05). These results indicate that a specific IgE response is useful in the diagnosis of active disease and to evaluate response to treatment.
Cryptosporidiosis in urban Zambian children: an analysis of risk factors.
Authors: Nchito M , Kelly P , Sianongo S , Luo N P , Feldman R , Farthing M , Baboo K S
Published: May 2017

In four crowded townships of Lusaka, Zambia, the prevalence of cryptosporidiosis in 222 children with diarrhea was 18%, with marked temporal and geographic variation over the course of one rainy season. Using data on the finding of oocysts of Cryptosporidium parvum in urban water supplies, the areas under study were categorized as high or low risk. Prevalence of cryptosporidiosis in children with diarrhea was higher in high risk areas after stratification by early/late stage of the rains (Mantel-Haenszel odds ratio [OR] = 2.9, 95% confidence interval [CI] = 1.3, 6.7; P = 0.008). Cryptosporidiosis was not associated with keeping animals, nutritional status, or parental education, but was apparently more common in breast fed children (OR = 2.7, 95% CI = 1.1, 6.9; P = 0.01), although the proportion of exclusively breast fed children was not measured. Since most of these infections were of short duration, we conclude that transmission of C. parvum can vary dynamically within one city and over short periods of time, and that water-borne contamination may be a substantial influence.
Ecology and demographics of hantavirus infections in rodent populations in the Walker River Basin of Nevada and California.
Authors: Boone J D , Otteson E W , McGwire K C , Villard P , Rowe J E , St Jeor S C
Published: May 2017

To study the ecologic correlates of hantavirus in deer mice (Peromyscus maniculatus), we sampled 114 sites in the Walker River Basin of Nevada and California in 1995-1996. Blood samples were tested for antibody to hantavirus, and a subset of samples was also tested for virus RNA by reverse transcription-polymerase chain reaction. Average prevalence of antibody-positive mice was 17%, with heavier males the most likely to be infected. Antibody prevalence varied within repeatedly sampled sites from 0% to 50% over the course of several months, suggesting possible infection cycles. Although there was no linear correlation between deer mouse density and antibody prevalence on sample sites, more complex relationships between density and prevalence appeared likely. Specifically, infections were less likely where rodent densities were lower than a critical threshold value. However, above this value, density had no effect on prevalence.
Mucosal leishmaniasis due to Leishmania (Viannia) panamensis in Colombia: clinical characteristics.
Authors: Osorio L E , Castillo C M , Ochoa M T
Published: May 2017

The Leishmaniases are a group of diseases whose clinical presentation is in part determined by the infecting species. Until recently, mucosal leishmaniasis was attributed exclusively to Leishmania (Viannia) braziliensis; however, the capacity of other species of the subgenus Viannia to invade mucosal tissue has been documented. This report examines the clinical characteristics of 23 parasitologically diagnosed patients with mucosal leishmaniasis due to L. (V.) panamensis from the Pacific Coast of Colombia seen at CIDEIM between 1985 and 1996. Most of the mucosal lesions 74% (17 of 23) were mild, with a short time of evolution (median = 2.5 months) and were present concomitantly with an active cutaneous lesion in 61% (14 of 23) of the cases. The simultaneous presentation of mucosal and active cutaneous lesions contrast with classical descriptions of mucosal leishmaniasis caused by L. (V.) braziliensis, and highlights the importance of early diagnosis of mucosal disease by the examination of mucosa in all cases of cutaneous leishmaniasis.
Efficacy of chemotherapy with benznidazole in children in the indeterminate phase of Chagas' disease.
Authors: Sosa Estani S , Segura E L , Ruiz A M , Velazquez E , Porcel B M , Yampotis C
Published: May 2017

A double-blind, randomized, clinical field trial was designed to test the efficacy and tolerance of a specific drug treatment in children in the indeterminate phase of infection by Trypanosoma cruzi. Children were treated with benznidazole at a dose of 5 mg/kg/day for 60 days or placebo and followed-up for 48 months. The treated children showed a significant decrease in geometric mean titers of antibodies against T. cruzi measured by indirect hemagglutination, indirect immunofluorescence, and ELISA. After a four year follow-up, 62% of the benznidazole-treated children and no placebo-treated child were seronegative for T. cruzi when tested by an ELISA using a T. cruzi flagellar calcium-binding protein (F29). Xenodiagnosis carried out after 48 months of follow-up was positive in 4.7% of the benznidazole-treated children and in 51.2% of the placebo-treated children. These results show the tolerance to and efficacy of benznidazole against T. cruzi in seropositive children six to 12 years of age. We used an early serologic marker of cure after treatment, consisting of a recombinant antigen implemented in a rapid, conventional serologic procedure.
Eradication of Aedes aegypti from a village in Vietnam, using copepods and community participation.
Authors: Vu S N , Nguyen T Y , Kay B H , Marten G G , Reid J W
Published: May 2017

In northern Vietnam, copepods of the genus Mesocyclops were used for biological control of Aedes aegypti, the principal vector of dengue viruses, by inoculation into wells, large cement tanks, ceramic jars, and other domestic containers that served as Ae. aegypti breeding sites. The use of Mesocyclops was complemented by community participation with respect to recycling to eliminate unused and discarded containers that collected rainwater and provided Ae. aegypti breeding sites that could not be treated effectively with Mesocyclops. Aedes aegypti disappeared from 400 houses of the treated village in August 1994 and has not reappeared, a result of particular significance, because there are virtually no other recorded instances of eradicating this mosquito anywhere in the world during the past 25 years, and certainly not with community-based approaches. When used in combination with community recycling, Mesocyclops is an easy and inexpensive method of Ae. aegypti control that should be effective for many communities in Vietnam and elsewhere.
Bancroftian filariasis in Tanzania: specific antibody responses in relation to long-term observations on microfilaremia.
Authors: Simonsen P E , Meyrowitsch D W
Published: May 2017

Following a 16-year clinical and parasitologic follow-up survey for Bancroftian filariasis in three endemic communities in northeastern Tanzania, serum antibody responses were analyzed in selected individuals in relation to the long-term observations on microfilaremia. Comparison of responses in three categories of adults (microfilaria [mf] positive at both surveys, mf positive at first but mf negative at the second survey, and mf negative at both surveys, respectively) indicated no significant differences between the mean levels of filarial-specific IgG1, IgG2, IgG3, IgG4, or IgE (measured by ELISA). However, specific IgG2 to the sheath of Wuchereria bancrofti mf (measured by an indirect fluorescence antibody test [IFAT]) was detected only in the third category. Comparison of responses in two categories of children born around the time of the first survey (to mf-positive and mf-negative mothers, respectively) showed a significantly higher mean level of filarial-specific IgG4 in the first than in the latter category, whereas the mean levels of filarial-specific IgG1, IgG2, IgG3, and IgE, and the prevalences of IgG2 IFAT positivity were similar. The overall prevalence of IgG2 IFAT positivity was considerably higher in the child study population (45.5%) than in the adult study population (16.7%). In both populations, however, a clear association between IgG2 IFAT positivity and a negative microfilarial status and negative specific circulating antigen status was seen. The study suggests that specific anti-sheath-antibodies are associated with an immunologic resistance mechanism that in the endemic community is expressed with highest prevalence in young individuals before development of patent microfilaremia.
Detection and quantification of soluble egg antigen in urine of Schistosoma haematobium-infected children from Kenya.
Authors: Kahama A I , Nibbeling H A , van Zeyl R J , Vennervald B J , Ouma J H , Deelder A M
Published: May 2017

While research on alternative diagnostic and morbidity markers for infection with Schistosoma haematobium has been going on for a long time, egg counts continue to be used as the gold standard, and infection intensity is thought to reflect the severity of the disease. However, this relationship is not always clear and fluctuation in egg output makes it difficult to classify prevalence correctly. The use of circulating adult worm antigen detection as an alternative diagnostic technique has been applied with varying success. However, this is a measure of worm burden and does not reflect the tissue egg load(s). In the present study we have used an assay that detects soluble egg antigen (SEA) in urine of S. haematobium-infected children, and we have evaluated the applicability of the assay as a diagnostic and morbidity indicator. To evaluate this assay, we have studied a group of 470 children from two schools (Tsunguni and Kibaokiche) in the Coast province of Kenya; 84.8% and 77% were egg-positive while the percentage positive as determined by the SEA-ELISA were 78.8% and 76.2% in Tsunguni and Kibaokiche, respectively. In both schools, SEA levels in urine of S. haematobium-infected children significantly correlated with egg counts (Pearson's r=0.73, P < 0.0001) and with hematuria (Spearman's r=0.65, P < 0.0001). In addition, urinary tract pathology as determined by ultrasound significantly correlated with the SEA levels in urine (Spearman's r=0.3, P < 0.001). The SEA-ELISA compared well with microhematuria within egg count classes and with egg counts within hematuria classes.
Schistosomiasis of the lower reproductive tract without egg excretion in urine.
Authors: Poggensee G , Kiwelu I , Saria M , Richter J , Krantz I , Feldmeier H
Published: May 2017

The individual and public health impact of female genital schistosomiasis (FGS) has been studied and FGS as a risk factor for acquiring human immunodeficiency virus is discussed. In a community-based study in Tanzania, 40% of the women of child-bearing age (n=543) showed excretion of Schistosoma haematobium eggs in the urine (median=2.2 eggs/10 ml of urine) and 32% (n=263) had S. haematobium eggs in their cervical tissue. Urinary and genital schistosomiasis coexisted in 62% of the women, but S. haematobium eggs were found in the cervix without detectable egg excretion in the urine in 23%. Only 43% of the FGS cases had hematuria. Since FGS frequently exists in women with scanty or no egg excretion in the urine and because this disease manifestation is a considerable individual and public health hazard in S. haematobium-endemic areas, mass treatment targeted to women of child-bearing age should be considered.
Prevalence and immune response to Entamoeba histolytica infection in preschool children in Bangladesh.
Authors: Haque R , Ali I M , Petri W A
Published: May 2017

Entamoeba histolytica infection was present in 5% and E. dispar in 13% of asymptomatic 2-5-year-old children from an urban slum of Dhaka, Bangladesh. Entamoeba dispar-infected children were no more likely than uninfected children to have serum antibodies to lectin. In contrast, all children infected with E. histolytica had serum antibodies to lectin. This anti-lectin response included antibodies against the carbohydrate recognition domain, which have been demonstrated in animal models to confer passive protection from amebiasis. Antibodies to lectin persisted in the sera of 17 children with E. histolytica infection over one year of follow-up, during which time E. histolytica infection cleared without treatment in 15, and with anti-amebic medication in two. We conclude that half of the children in this population have serologic evidence of amebiasis by five years of age, and that an anti-lectin serum antibody response is associated with limitation of E. histolytica infection to the colon.
Establishing a laboratory for surveillance of invasive bacterial infections in a tertiary care government hospital in a rural province in the Philippines.
Authors: Herva E , Sombrero L , Lupisan S , Arcay J , Ruutu P
Published: May 2017

A clinical bacteriologic laboratory was established in a tertiary care government hospital in The Philippines, where expert bacteriologic laboratories do not usually exist at this level of health care. The laboratory was jointly established by the Research Institute for Tropical Medicine (RITM) (Manila, The Philippines) and the National Public Health Institute (KTL) (Helsinki, Finland). The laboratory was planned, its personnel were trained, and its functioning was continuously supported by the RITM and KTL. The following aspects were of utmost importance in establishing the laboratory and launching its work: 1) the support of the RITM bacteriologic laboratory, with back-up and consultations from KTL; 2) creation and maintenance of personal contacts between clinicians and laboratory staff with an emphasis on clinical relevance and rapid reporting of laboratory results; 3) the consideration of the quality aspects of the work from the start; and 4) keen follow-up of the bacteriologic results and their clinical significance and use, of practical laboratory work, and of quality assurance aspects. In the first two years of its operation, the laboratory identified Streptococcus pneumoniae and Haemophilus influenzae as the most important causes of severe pneumonia, sepsis or meningitis in children less than two years of age, and Salmonella typhi as the most frequent significant isolate from the blood cultures, being found most often in school age children and young adults.
Strongyloides stercoralis hyperinfection associated with human T cell lymphotropic virus type-1 infection in Peru.
Authors: Gotuzzo E , Terashima A , Alvarez H , Tello R , Infante R , Watts D M , Freedman D O
Published: May 2017

A study was conducted in Lima, Peru to determine if patients with Strongyloides hyperinfection had human T cell lymphotropic virus type-1 (HTLV-I) infection. The study included patients with Strongyloides hyperinfection and a control group consisted of sex- and age-matched asymptomatic healthy individuals whose stools were negative for Strongyloides. A third group included patients with intestinal strongyloidiasis. Sera from each study subject were tested for HTLV-1/2I by an ELISA and Western blot. The HLTV-1 infection rates (85.7%, 18 of 21) were significantly (P < 0.001) associated with Strongyloides hyperinfection compared with the control group (4.7%, 1 of 21). The HTLV-1 rate (10%, 6 of 62) for patients with intestinal strongyloidiasis was significantly (P < 0.001) lower than patients with Strongyloides hyperinfection, but did not differ significantly (P > 0.05) from the control group. The association of HTLV-1 infection was observed among 17 of 19 patients more than 20 years of age and one of two younger patients. None had HTLV-2 infection. In conclusion, Strongyloides hyperinfection among Peruvian patients was highly associated with HTLV-1 infection.
Linkage of a gene causing malaria refractoriness to Diphenol oxidase-A2 on chromosome 3 of Anopheles gambiae.
Authors: Romans P , Black W C , Sakai R K , Gwadz R W
Published: May 2017

An inbred line of the African malaria vector Anopheles gambiae is refractory to development of malaria parasites. It is homozygous for a 4.3-kb Sal I restriction fragment at the Dox-A2 locus, whereas the parent population is polymorphic at this locus, and a susceptible line is homozygous for an alternate 3.85-kb fragment. The Dox-A2 locus is located in the middle of chromosome 3R, in division 33B, and is tightly linked to a cluster of genes including Dopa decarboxylase that are involved in the production of melanin. Because the refractoriness phenotype, melanotic encapsulation of ookinete/oocysts, might involve activation of or alteration in one or more of these genes, we performed genetic crosses to determine whether a previously identified Plasmodium cynomolgi Ceylon refractoriness gene, Pif-C, is linked to Dox-A2. Backcross mosquitoes fed on one infected monkey developed infections of < or = 100 oocysts. About 50% of these mosquitoes appeared phenotypically refractory, as expected for the backcross performed, but gave slight evidence of linkage between a refractoriness gene and Dox-A2. In contrast, females fed on a monkey that yielded higher infection levels, up to > 300 oocysts, showed clear evidence of linkage between a refractoriness gene and Dox-A2. We conclude that this Dox-A2-linked refractoriness gene is expressed under conditions particular to the higher infection levels, or that environmental factors obscured the genetic effect of this gene at lower infection levels.
Granulomatous inflammatory response to recombinant filarial proteins of Brugia species.
Authors: Rao U R , Nasarre C , Coleman S U , Horohov D W , Klei T R
Published: May 2017

The lymphatic inflammatory response in Brugia-infected jirds peaks early during primary infections and then decreases in severity as judged by the numbers of lymph thrombi present within these vessels. Antigen-specific hypersensitivity reactions in these animals was measured by a pulmonary granulomatous inflammatory response (PGRN) induced by somatic adult worm antigen (SAWA)-coated beads, and by cellular proliferative responses of renal lymph node cells. The kinetics of these responses temporally correspond to lymphatic lesion formation. The importance of any single antigen to the induction of this inflammatory response has not been elucidated. In this study, the PGRN was used to measure the cellular immune response to four recombinant filarial proteins during the course of a primary B. pahangi infection. These proteins were BpL4, glycoprotein (glutathione peroxidase) gp29, heat shock protein (hsp) 70, and filarial chitinase. All were fusion proteins of maltose-binding protein (MBP). Control beads included those coated with diethanolamine (DEA), SAWA, or MBP. The measurements of PRGN were made at 14, 28, 56, and > 150 days postinfection (PI) in infected jirds, in jirds sensitized with SAWA, and in uninfected jirds. The secretory homolog of glutathione peroxidase gp29 was the only recombinant protein tested that induced a significantly greater PGRN (P < 0.05) than controls. This was seen at 28 days PI. These observations indicate that gp29 may be part of the worm antigen complex that induces an early inflammatory response, a response similar to that observed with SAWA. These studies indicate that this approach is useful in investigating the functional ability of specific proteins in the induction and down-regulation of immune-mediated inflammatory responses elicited by filarial parasites. Absence of a granulomatous response to the other recombinant proteins used may be related to the nature and sensitivity of the assay used or the character of recombinant proteins tested.
Integration of neuro-endocrine immune responses in defense of mucosal surfaces.
Authors: Befus A D , Mathison R , Davison J
Published: May 2017

Neuro-endocrine immunology, a field arising from curiosity about the mind-body connection, is evolving rapidly. From intriguing, but seemingly unexplainable observations with human infections and disease, experimental systems have been developed that provide a solid scientific basis for new understanding. There have been major efforts to understand influences of the nervous system on immune and inflammatory responses, e.g., innervation of the immune system, molecular communication pathways, and complex phenomena such as conditioning of immune responses and mechanisms of host defenses. In turn, the immune system communicates with the neuro-endocrine systems. Imbalances in the neuro-endocrine-immunologic circuitry are relevant in host defenses and in injury and repair. Examples of these themes in neuro-endocrine-immunology arise in several host-parasite models of neurogenic inflammation, immediate hypersensitivity responses, and granuloma formation. The hypothalamic-pituitary-adrenal axis and the cervical sympathetic trunk-submandibular gland axis provide important models to enhance understanding of this poorly known component of the host-parasite relationship.
Risk of Helicobacter pylori infection among long-term residents in developing countries.
Authors: Becker S I , Smalligan R D , Frame J D , Kleanthous H , Tibbitts T J , Monath T P , Hyams K C
Published: May 2017

The seroprevalence and incidence of Helicobacter pylori infection were determined among 312 North American missionaries who were serving in developing countries between 1967 and 1984. The majority (81%) resided in sub-Saharan Africa. When initially evaluated, the missionaries had a mean age of 40 years, 65% were female, and all were of white race/ethnicity. An ELISA showed that the initial prevalence of IgG antibody to H. pylori was 17%. After a mean of 7.4 years of service (1917 person-years of exposure), 37 (14%) of 259 initially seronegative subjects seroconverted to anti-H. pylori, giving an annual incidence of 1.9%. These data indicate a relatively higher risk of H. pylori infection among missionaries compared with an annual incidence of seroconversion of 0.3-1.0% in industrialized nations. Long-term residents in developing countries should be evaluated for H. pylori infection when gastrointestinal symptoms develop.
Variation in oral susceptibility to dengue type 2 virus of populations of Aedes aegypti from the islands of Tahiti and Moorea, French Polynesia.
Authors: Vazeille-Falcoz M , Mousson L , Rodhain F , Chungue E , Failloux A B
Published: May 2017

Twenty three samples of Aedes aegypti populations from the islands of Tahiti and Moorea (French Polynesia) were tested for their oral susceptibility to dengue type 2 virus. The high infection rates obtained suggest that the artificial feeding protocol used was more efficient than those previously described. Statistical analysis of the results allowed us to define two distinct geographic areas on Tahiti with respect to the susceptibility of Ae. aegypti: the east coast, with homogeneous infection rates, and the west coast, with heterogeneous infection rates. No geographic differences could be demonstrated on Moorea. The possible mechanisms of this phenomenon are discussed in connection with recent findings on the variability of susceptibility of Ae. aegypti to insecticides.
Production of lethal infection that resembles fatal human disease by intranasal inoculation of macaques with Japanese encephalitis virus.
Authors: Myint K S , Raengsakulrach B , Young G D , Gettayacamin M , Ferguson L M , Innis B L , Hoke C H , Vaughn D W
Published: May 2017

Twelve rhesus macaques (Macaca mulatta) challenged intranasally with a wild-type Japanese encephalitis virus (JEV) developed clinical signs 11-14 days later. Tissues from the cerebral cortex, cerebellum, brainstem, thalamus, meninges, and all levels of the spinal cord were stained for JEV antigen with hyperimmune mouse ascitic fluid and streptavidin-alkaline phosphatase; immunofluorescent staining was also done on frozen sections. Viral antigen was found in all cell layers of the cerebellum, the gray matter of the thalamus and brainstem, and the ventral horn of all levels of the spinal cord. Staining was limited to neurons and their processes. Histopathologic changes were limited to the nervous system and characterized by nonsuppurative meningoencephalitis. These results were comparable with those of previous studies done with human autopsy tissues. Intranasal inoculation of rhesus monkeys with JEV was effective in producing clinical disease comparable with natural disease in humans and may serve as a model to evaluate protective efficacy of candidate JEV vaccines.
Plasmodium falciparum clinical malaria in Dielmo, a holoendemic area in Senegal: no influence of acquired immunity on initial symptomatology and severity of malaria attacks.
Authors: Rogier C , Ly A B , Tall A , CissÃ© B , Trape J F
Published: May 2017

Six hundred eighty-nine Plasmodium falciparum malaria attacks were observed during a three-year period among 226 inhabitants of the village of Dielmo, Senegal, an area of high malaria transmission. Malaria attacks were defined as clinical episodes with fever (body temperature > or = 38.0 degrees C) or reporting of fever or headache or vomiting, associated with a parasite:leukocyte ratio above an age-dependent pyrogenic threshold identified in this population. The symptom frequencies were tested against age, gender, and parasite density using a random-effect logistic regression model and the study of distinguishable clinical presentations was carried out by multi-correspondence analysis. There was little difference between the severity of symptoms during the initial course of attacks in young children and adults, and this severity was not correlated with the duration of the pathologic episode. It was not possible to distinguish objectively different malaria attack types according to the severity of clinical manifestations. In contrast, the duration of fever, symptoms, and parasite clearance were significantly longer among the youngest children than among the oldest children and adults. These findings suggest that of the two components of protective immunity, anti-parasite immunity and anti-toxic immunity, only the first would play a major role as age increases. They suggest also that the initial clinical presentation of malaria attacks is not predictive of the level of protective immunity.
Short report epidemiologic studies on cutaneous leishmaniasis in eastern Panama.
Authors: Christensen H A , de Vasquez A M , Petersen J L
Published: May 2017

The Panamanian Ministry of Health, through the Interamerican Development Bank, contracted the Gorgas Memorial Laboratory to conduct epidemiologic studies on leishmaniasis and malaria in eastern Panama from July 1984 through June 1985. Preliminary results of the biomedical and entomologic teams investigating the epidemiology of cutaneous leishmaniasis in the eastern part of the country are presented in this short report. The principal findings of the study revealed 1) a large disparity in the incidence and prevalence of the disease among the five communities investigated; 2) the appearance of self-cures without the benefit of effective treatment; 3) a relatively high percentage of subclinical cases; and 4) determination of the sandfly vector species for each community. Also reported here is a case of a double infection with two distinct species of Leishmania, L. mexicana and L. amazonensis, in a single individual.
Adverse effects in patients with acute falciparum malaria treated with artemisinin derivatives.
Authors: Price R , van Vugt M , Phaipun L , Luxemburger C , Simpson J , McGready R , ter Kuile F , Kham A , Chongsuphajaisiddhi T , White N J , Nosten F
Published: May 2017

In prospective studies of acute uncomplicated, multidrug-resistant falciparum malaria on the western border of Thailand, the oral artemisinin derivatives were used alone in the treatment of 836 patients (artesunate 630, artemether 206), were combined with mefloquine (15-25 mg base/kg) in 2,826 patients, and mefloquine alone was used in 1,303 patients. The combined regimens of mefloquine plus an artemisinin derivative were associated with more side effects than those with an artemisinin derivative alone; acute nausea (31% versus 16%), vomiting (24% versus 11%), anorexia (51% versus 34%), and dizziness (47% versus 15%) (P < 0.001). Oral artesunate and artemether alone were very well tolerated. There was no difference in the incidence of possible adverse effects between the two drugs, and no evidence that either derivative caused allergic reactions, neurologic or psychiatric reactions, or cardiovascular or dermatologic toxicity. Blackwater fever occurred in three patients treated with mefloquine plus artesunate regimens. Oral artesunate and artemether are safe and well tolerated antimalarial drugs.