bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytoadherence characteristics of Plasmodium falciparum isolates in Thailand using an in vitro human lung endothelial cells model.
Authors: TraorÃ© B , Muanza K , Looareesuwan S , Supavej S , Khusmith S , Danis M , Viriyavejakul P , Gay F
Published: May 2017

Using an in vitro model of human lung endothelial cells, we studied different characteristics of Plasmodium falciparum isolates as potential factors for malaria severity in 2 Thai patient groups: 27 with complicated malaria and 42 with uncomplicated malaria. In regard to binding properties, no association existed between cytoadherence and rosette phenotypes (P = 0.1) and hypothrombocytemia increased the cytoadherence level (P = 0.007). Cytoadherence was significantly associated with malaria severity (P = 0.05) in contrast to rosette formation (P = 0.9). Intercellular adhesion molecule-1 and chondroitin-4-sulfate were major receptors of cytoadherence in those with complicated malaria compared with those with uncomplicated malaria (P < 10(-4)). Chondroitin-4-sulfate could act as a putative receptor for malaria complications in non-pregnant women. CD36 was the main receptor in patients with uncomplicated malaria (P < 10(-3)). Vascular cell adhesion molecule-1 and E-selectin played a minor role in 2 groups (P = 0.6). Qinghaosu derivatives were more efficient than other antimalarial drugs, but a positive correlation was observed between the 50% inhibitory concentrations of halofantrine and quinine and the number of adhesive parasitized red blood cells, suggesting their influence on cytoadherence.
The changing in vitro susceptibility pattern to pyrimethamine/sulfadoxine in Plasmodium falciparum field isolates from Kilifi, Kenya.
Authors: Mberu E K , Mosobo M K , Nzila A M , Kokwaro G O , Sibley C H , Watkins W M
Published: May 2017

Two clinical trials that used Falcidin (Cosmos Ltd., Nairobi, Kenya), the antifolate combination of pyrimethamine/sulfadoxine (PM/SD), as treatment for non-severe falciparum malaria in children at Kilifi, Kenya in 1987-1988 and 1993-1995 have presented an opportunity to assess in vitro the susceptibility trend of Plasmodium falciparum to PM and SD over time on the Kenya coast. The first set of isolates was collected prior to the introduction of PM/SD into the Kenya Medical Research Institute/Wellcome Trust Research unit while the second set was taken soon after PM/SD was introduced in the study area as the first-line treatment drug for uncomplicated falciparum malaria. In the first trial, 69 isolates collected before and after treatment of malaria with PM/SD were tested directly in the field for susceptibility to PM and SD using the standard in vitro micro-test technique, with minimal levels of folate. In the second trial, 97 isolates similarly collected were adapted to culture, and tested as described elsewhere. In both studies, PM and SD susceptibility tests were done separately. There was a highly significant decrease (P < 0.01) in the in vitro sensitivity of P. falciparum isolates to PM and SD between the two trials. In the first trial, the isolates were either sensitive to both PM and SD or resistant to PM and sensitive to SD. During the second trial, isolates were either resistant to PM and sensitive to SD or resistant to both drugs. These results are important in estimating the useful therapeutic life (UTL) of PM/SD in this area and in identifying alternative antifolate drugs.
Density and spatial distribution of Ixodes pacificus (Acari: Ixodidae) in two recreational areas in north coastal California.
Authors: Li X , Peavey C A , Lane R S
Published: May 2017

The density and distribution of Ixodes pacificus was assessed at 2 parks in north coastal California. The density of I. pacificus adults and nymphs varied significantly between years, trails, and sides of trails. Adult ticks occurred on vegetation along sun-exposed trails in January through March, their density (0-1.93 per 20 m) correlated with brush density, trail width, and presence of an uphill slope. Nymphs (0.06-5.10 per 20 m) occurred in leaf litter along shaded trails in May-July. Adult I. pacificus were rare at picnic sites (0.00-0.24 per 20 m), but nymphal densities (0.93-2.37 per 20 m) were comparable with those along some shaded trails. The prevalence of Borrelia burgdorferi in ticks (2.8% overall) did not differ significantly between locations, years, or stages. We conclude that the risk of acquiring Lyme disease in these sites is low, but varies among trails, seasons, and years.
PCR-RFLP analysis of the ITS2 region to identify Schistosoma haematobium and S. bovis from Kenya.
Authors: Barber K E , Mkoji G M , Loker E S
Published: May 2017

Schistosoma haematobium, primarily a human parasite, and the closely related Schistosoma bovis from ruminants, are sympatric in many African countries such as Kenya. Because these two species 1) can inhabit the same Bulinus snails, 2) may be found in the same freshwater habitat, and 3) have morphologically similar cercariae, better means are needed to tell them apart. The second internal transcribed spacer (ITS2) region of the ribosomal gene complex (rDNA) of recent Kenyan isolates of both species was sequenced and found to be a 98% match. The S. bovis sequences were nearly identical (99%) to conspecific sequences from Niger; the S. haematobium sequences were nearly identical (99%) to conspecific sequences from Egypt, Mali, and Niger. Restriction fragment length polymorphism (RFLP) analysis of a 480 base pair (bp) PCR product containing the ITS2 region using two restriction enzymes, Taq1 and Sau3A1, yielded species-specific fragment patterns that allowed successful identification of a single S. haematobium cercaria. The protocol outlined here is useful in providing a rapid, one-day identification of S. haematobium (and likely S. bovis) cercariae (the infective larval stage) and/or other life cycle stages in a basic molecular biology laboratory. By helping to determine whether schistosome-infected bulinid snails in a particular body of water are transmitting a human or an animal schistosome, or both, this analysis will aid in disease control and in ongoing epidemiological studies.
Genetic variation of Japanese encephalitis virus in Taiwan.
Authors: Jan L R , Yueh Y Y , Wu Y C , Horng C B , Wang G R
Published: May 2017

A 280-nucleotide sequence from the capsid-premembrane (C/preM) gene region of 44 Japanese encephalitis (JE) virus strains isolated in Taiwan from mosquitoes from 1983 to 1994, and 3 strains, (Ling [1965], Chang [1965], and HV1 [1958]) isolated from human brain were analyzed by direct sequencing of reverse transcription-polymerase chain reaction (RT-PCR) amplified products and compared with the corresponding sequences of reference strains. The overall sequence homology of the 47 isolates was > or = 93.3%. Taking 12% nucleotide divergence as a cut-off value, all isolates fell into genotype 3, which included strains from Japan, China, the Philippines, Sri Lanka, India, and Nepal. High nucleotide homology was observed among isolates from different regions of Taiwan and different time periods; on the other hand, high variation existed among isolates from the same region and time period. Phylogenetic analysis showed that the 47 Taiwan isolates fell into three clusters. Twenty-five isolates formed cluster 1, 18 isolates cluster 2, and four isolates cluster 3. Isolates in cluster 1 showed greater (< or = 2.9%) intragroup divergence compared to those in cluster 2 (< or = 1.1%) or cluster 3 (< or = 0.7%). The majority of isolates from northern (73.3%) and central (60%) Taiwan belonged to cluster 1, whereas most isolates (66.7%) from southern Taiwan belonged to cluster 2. Comparison with other Asian JE virus strains showed that isolates of cluster 1 were more specific to Taiwan than isolates of cluster 2 and cluster 3.
Tissue responses in experimental schistosomiasis japonica in the pig: a histopathologic study of different stages of single low- or high-dose infections.
Authors: Hurst M H , Willingham A L , Lindberg R
Published: May 2017

The tissue responses of pigs exposed to either 100 or 2,000 Schistosoma japonicum cercariae were examined at 4, 11, 17, and 24 weeks postinfection (PI) to explore the pig as an animal model for pathologic aspects of human schistosomiasis japonica. Egg granulomas were present in the liver, intestine, and occasionally in the lungs from 11 weeks PI. There were also many free eggs and early exudative reactions to eggs in the intestine. At 11 weeks PI, pigs in the higher dose group showed marked periportal and septal fibrosis with minimal parenchymal destruction. Thereafter, lesions regressed spontaneously as the pigs underwent a self-cure. The lower dose group showed only mild lesions throughout the study. The degree of hepatic fibrosis was correlated with the density of eggs and granulomas in liver tissue. The results indicate that the pig would be particularly useful for studies of the development and resolution of schistosomal hepatic fibrosis, and also for investigations of the mechanisms behind the self-cure phenomenon.
Erhaia (Gastropoda: Rissooidea): phylogenetic relationships and the question of Paragonimus coevolution in Asia.
Authors: Wilke T , Davis G M , Gong X , Liu H X
Published: May 2017

The human lung fluke Paragonimus is transmitted by gastropod taxa of two superfamilies: Ceritheoidea and Rissooidea. The question whether or not Paragonimus shows the same specificity of host-parasite coevolved relationship as the human blood fluke Schistosoma was inspired by the finding of two sympatric snail species as hosts for Paragonimus skrjabini in Fujian Province, China: Gammatricula and Erhaia. The former species can clearly be classified as Pomatiopsidae: Triculinae. The latter has previously been classified as Pomatiopsidae: Pomatiopsinae. However, this classification based on anatomical characteristics is uncertain. In order to obtain a robust phylogenetic hypothesis for Erhaia, we have studied three gene fragments from this taxon as well as from twelve related taxa. The data show that the species involved represent four families: Pomatiopsidae, Hydrobiidae, Cochliopidae (here raised to family status), and Amnicolidae. Erhaia fits securely into the Amnicolidae. This indicates that P. skrjabini has not coevolved with snail lineages. However, P. skrjabini has so far only been reported from rissooidean snails, whereas members of the Paragonimus westermani complex have only been found in ceritheoidean snails. The implication is that there is a host specificity on the superfamily level. However, Asian freshwater species of the Ceritheoidea and Rissooidea usually are not sympatric and often prefer different habitats. It is therefore possible that ecological niche partitioning plays the primary role for Paragonimus evolution.
Phylogeny and molecular taxonomy of the Rhodniini derived from mitochondrial and nuclear DNA sequences.
Authors: Monteiro F A , Wesson D M , Dotson E M , Schofield C J , Beard C B
Published: May 2017

Eleven species of Rhodnius and one of Psammolestes were compared by DNA sequence analysis of fragments of the mitochondrial large subunit ribosomal RNA (mtlsurRNA), the mitochondrial cytochrome b (mtCytb), and the D2 variable region of the 28S nuclear RNA (D2), totaling 1,429 base pairs. The inferred phylogeny, using Triatoma infestans as an outgroup, revealed two main clades within the Rhodniini--one, including the prolixus group of species (Rhodnius prolixus, Rhodnius robustus, Rhodnius neglectus, and Rhodnius nasutus) together with Rhodnius domesticus and Rhodnius neivai, and the other comprising two groups formed by Rhodnius pictipes plus Rhodnius brethesi, and Rhodnius ecuadoriensis plus Rhodnius pallescens. Psammolestes tertius appeared most closely related to the prolixus group. The analysis strongly supports the validity of R. robustus as a species distinct from others of the prolixus group, but suggests higher genetic structuring of R. robustus populations compared to the other species. Although R. robustus has been found naturally infected by Trypanosoma cruzi, the fact that it is apparently entirely sylvatic and unable to establish in homes suggests that it is of no great importance as a Chagas disease vector in humans.
The epidemiology of schistosomiasis in Egypt: Qalyubia Governorate.
Authors: Habib M , Abdel Aziz F , Gamil F , Cline B L
Published: May 2017

The primary objectives of this study, carried out in Qalyubia Governorate in Egypt (south-central Nile Delta), were to continue tracking historical trends of infection prevalence of Schistosoma mansoni and S. haematobium, determine whether satellites (ezbas) of mother villages differed significantly with respect to schistosomiasis transmission, and to asses schistosomiasis-induced morbidity on a population basis using ultrasonography. Our study revealed that S. haematobium has virtually disappeared from Qalyubia governorate, and that S. mansoni prevalence continues to decline slowly (17% in 1991 compared with 19% in 1990). The prevalence of intestinal schistosomiasis was actually higher in the mother villages than in the ezbas of the same villages, indicating that prevalence based on surveys of villages alone did not (at least for Qalyubia) cause underestimates of true prevalence. (A mother village is the large village in an area that includes hamlets or ezbas. In many areas, the infection rate in ezbas is significantly higher than in the larger central village.) Ultrasonographic studies revealed that less than 3% of the population had stage 2 or stage 3 periportal fibrosis, commonly associated with chronic schistosomiasis mansoni. This low level of morbidity was consistent with earlier data from Qalyubia, which also showed a low level of S. mansoni-induced morbidity in this governorate.
National progress in dengue vector control in Vietnam: survey for Mesocyclops (Copepoda), Micronecta (Corixidae), and fish as biological control agents.
Authors: Nam V S , Yen N T , Holynska M , Reid J W , Kay B H
Published: May 2017

This paper describes the process of expanding a successful dengue control program in 3 provinces in northern Vietnam into a national one and demonstrates the presence of a rich, low-cost resource that could have similar applicability to other countries in the region. The cornerstone of the preventive strategy is larval control of Aedes aegypti (L.), the major vector, using predators such as copepods, Mesocyclops spp., aided by the corixid bug Micronecta quadristrigata Bredd, and fish in large water storage containers. From 1989 to 1998, 9 species of Mesocyclops (M. woutersi Van de Velde, M. aspericornis (Daday), M. ruttneri Kiefer, M. thermocyclopoides Harada, M. affinis Van de Velde, M. ogunnus Onabamiro, M. yenae Holynska, M. cf. pehpeiensis Hu, and M. dissimilis Defaye and Kawabata) were found in natural and artificial habitats in 26 provinces throughout Vietnam. The predatory capacities of 6 of these were evaluated in the laboratory. This indicated that daily consumption/killing averaged between 16 and 41 Ae. aegypti larvae per copepod. From detailed evaluations in 9 provinces, Mesocyclops spp. were surprisingly common in 8,413 artificial containers (concrete tanks, wells, ornamental ponds and in the south, large jars). Because of existing practices for washing and water transfer from ponds and lakes in Ha Tay and Ha Bac, Mesocyclops spp. already occurred in 60-100% of the water storage containers. When the relationship between the presence or absence of Mesocyclops and Aedes larvae in 5,111 containers was analyzed by the chi-square test, their distributions were significantly related, indicating control (odds ratio = 0.56). When 3,426 containers that did not contain Mesocyclops or fish were analyzed in relation to the distribution of Aedes larvae, those with Micronecta also had significantly less Aedes (odds ratio = 0.43). Therefore, this study demonstrates that there is an abundance of local Mesocyclops spp. in Vietnam that can be incorporated into specifically designed community-based control programs aided by Micronecta and fish.
Effect of Plasmodium falciparum parasitemia density on hemoglobin concentrations among full-term, normal birth weight children in western Kenya, IV. The Asembo Bay Cohort Project.
Authors: McElroy P D , ter Kuile F O , Lal A A , Bloland P B , Hawley W A , Oloo A J , Monto A S , Meshnick S R , Nahlen B L
Published: May 2017

The relative importance of acute high-density versus persistent low-density Plasmodium falciparum parasitemia in contributing to the public health problem of malarial anemia remains unclear. The Asembo Bay Cohort Project in western Kenya collected monthly hemoglobin (Hb) and parasitologic measurements and biweekly assessments of antimalarial drug use among 942 singleton live births between 1992 and 1996. A mixed-model analysis appropriate for repeated measures data was used to study how time-varying parasitemia and antimalarial drug exposures influenced mean Hb profiles. Incidence of World Health Organization-defined severe malarial anemia was 28.1 per 1,000 person-years. Among children aged less than 24 months, concurrent parasitemia was significantly associated with lower mean Hb, especially when compared to children with no concurrent parasitemia. Increased densities of the 90-day history of parasitemia preceding Hb measurement was more strongly associated with mean Hb levels than concurrent parasitemia density. While the highest quartile of 90-day parasitemia history was associated with lowest mean Hb levels, children in the lowest 90-day exposure quartile still experienced significantly lower Hb levels when compared to children who remained parasitemia-free for the same 90-day period. The results highlight the importance of collecting and analyzing longitudinal Hb and parasitologic data when studying the natural history of malarial anemia.
New insights on the emergence of cholera in Latin America during 1991: the Peruvian experience.
Authors: Seas C , Miranda J , Gil A I , Leon-Barua R , Patz J , Huq A , Colwell R R , Sack R B
Published: May 2017

After a century of absence, in late January 1991, Vibrio cholerae invaded the Western Hemisphere by way of Peru. Although a number of theories have been proposed, it is still not understood how that invasion took place. We reviewed the clinical records of persons attending hospital emergency departments in the major coastal cities of Peru from September through January of 1989/1990 and 1990/1991. We identified seven adults suffering from severe, watery diarrhea compatible with a clinical diagnosis of cholera during the four months preceding the cholera outbreak, but none during the previous year. The patients were scattered among five coastal cities along a 1,000 km coastline. We postulate that cholera vibrios, autochthonous to the aquatic environment, were present in multiple coastal locations, and resulted from environmental conditions that existed during an El Nino phenomenon. Once introduced into the coastal communities in concentrations large enough for human infection to occur, cholera spread by the well-known means of contaminated water and food.
Detection of Fasciola hepatica infection in a community located in the Ecuadorian Andes.
Authors: Trueba G , Guerrero T , Fornasini M , Casariego I , Zapata S , Ontaneda S , Vasco L
Published: May 2017

The presence of fascioliasis was assessed in four Andean communities using an enzyme-linked immunosorbent assay (ELISA) test to measure antibodies against Fasciola hepatica excretion-secretion antigens. Six percent (9 out of 150) of the individuals in one community were ELISA-positive for these antibodies. Fecal samples from two of the ELISA-positive individuals contained F. hepatica ova. All of the ELISA-positive cases, except for one, were children within the ages of 9 to 12 years.
Prevalence of antibodies to hepatitis E in two rural Egyptian communities.
Authors: Fix A D , Abdel-Hamid M , Purcell R H , Shehata M H , Abdel-Aziz F , Mikhail N , el Sebai H , Nafeh M , Habib M , Arthur R R , Emerson S U , Strickland G T
Published: May 2017

A population-based serosurvey in two rural Egyptian communities was used to assess age-specific prevalence of antibody to hepatitis E virus (anti-HEV). One community is in the Nile Delta (11,182 inhabitants; 3,997 participants) and the other in Upper Egypt (10,970 inhabitants; 6,029 participants). Samples were tested for anti-HEV with a commercial enzyme-linked immunoassay (ELISA) based on antigens derived from open reading frame (ORF)2 and ORF3. Although there was a clear difference in sensitivity among the lots of the commercial test used, it was still possible to determine the seroprevalence. The seroprevalence of anti-HEV exceeded 60% in the first decade of life, peaked at 76% in the second decade and remained above 60% until the eighth decade. Prevalence of this magnitude is among the highest reported in the world, with an age-specific pattern more similar to hyperendemic hepatitis A virus transmission than generally described. Lot-to-lot variation in the sensitivity of the commercial ELISA kit highlights a problem when comparing seroepidemiologic studies of different populations.
Quantitative competitive PCR as a technique for exploring flea-Yersina pestis dynamics.
Authors: Engelthaler D M , Hinnebusch B J , Rittner C M , Gage K L
Published: May 2017

We used a quantitative competitive polymerase chain reaction assay to quantify Yersinia pestis loads in fleas and bacteremia levels in mice that were used as sources of infectious blood meals for feeding the fleas. Xenopsylla cheopis, the Oriental rat flea, achieved higher infection rates, developed greater bacterial loads, and became infectious more rapidly than Oropsylla montana, a ground squirrel flea. Both flea species required about 10(6) Y. pestis cells per flea to be able to transmit to mice. Most fleas that achieved these levels, however, were incapable of transmitting. Our results suggest that at the time of flea feeding, host blood must contain > or = 10(6) bacteria/ml to result in detectable Y. pestis infections in these fleas, and > or = 10(7) bacteria/mL to cause infection levels sufficient for both species to eventually become capable of transmitting Y. pestis to uninfected mice. Yersinia pestis colonies primarily developed in the midguts of O. montana, whereas infections in X. cheopis often developed simultaneously in the proventriculus and the midgut. These findings were visually confirmed by infecting fleas with a strain of Y. pestis that had been transformed with the green fluorescent protein gene.
Mosquito isolates of Ross River virus from Cairns, Queensland, Australia.
Authors: Harley D , Ritchie S , Phillips D , van den Hurk A
Published: May 2017

During 1996-1998 60,619 mosquitoes were collected around Cairns, Australia and processed for Alphavirus isolation. Thirty-three isolates of Ross River (RR) virus were made from 9 species, Aedes imprimens, Aedes kochi, Aedes notoscriptus, Aedes vigilax, Culex annulirostris, Culex gelidus, Mansonia septempunctata, Verrallina (formerly Aedes) carmenti, and Verrallina lineatus. Attempts to isolate RR virus from 121 Aedes aegypti were unsuccessful. Twenty-six (79%) of the isolates came from within 1 km of a colony of spectacled flying-foxes, Pteropus conspicillatus. The minimum infection rate for these mosquitoes was 1.0 compared with 0.2 per 1,000 for mosquitoes trapped at all other sites. Ross River virus has not previously been isolated from Ae. imprimens, Cx. gelidus, Ma. septempunctata, Ve. carmenti, or Ve. lineatus. This is also the first isolation of an arbovirus from Cx. gelidus in Australia. In conclusion, the vector status of Ve. carmenti, Ae. aegypti and Ma. septempunctata warrants further study. This study also provides evidence that P. conspicillatus may be a reservoir host.
Antibody responses to Plasmodium falciparum: evolution according to the severity of a prior clinical episode and association with subsequent reinfection.
Authors: Luty A J , Ulbert S , Lell B , Lehman L , Schmidt-Ott R , Luckner D , Greve B , Matousek P , Schmid D , Herbich K , Dubois B , Deloron P , Kremsner P G
Published: May 2017

We measured sporozoite- and total parasite antigen-specific IgG and IgM antibodies before and after treatment in matched groups of Gabonese children who presented with either mild or severe Plasmodium falciparum malaria. We investigated the influence of various parameters on these antibody responses, including clinical presentation, age, and post-treatment reinfection profiles. IgG but not IgM responses were strongly influenced by both clinical and parasitological status. IgG responses to the repeat region of the circumsporozoite protein, which were low at admission, particularly so in those with severe anemia, increased after treatment but showed no association with either age or reinfection profiles. Total parasite antigen-specific IgG responses were strongly influenced by parasitological status, and also differed significantly when segregated according to clinical status at admission, age, and reinfection histories. Most notably, anti-parasite IgG responses measured when children were parasite-free were higher and a good indicator of recent reinfections in those who presented with mild rather than with severe malaria. The profile of responses in the latter group suggests some immune system dysfunction, which may reflect the induction of tolerance to parasite antigens.
Assessment of the antimalarial potential of tetraoxane WR 148999.
Authors: Vennerstrom J L , Ager A L , Andersen S L , Grace J M , Wongpanich V , Angerhofer C K , Hu J K , Wesche D L
Published: May 2017

The antimalarial peroxide, dispiro-1,2,4,5-tetraoxane WR 148999, was synergistic with chloroquine, quinine, mefloquine, and artemisinin against both D6 and W2 clones of Plasmodium falciparum. In consideration of the contrasting antagonism between artemisinin and chloroquine, these drug combination data imply that WR 148999 and artemisinin may not share a common mechanism of action. For Plasmodium berghei-infected mice given oral, subcutaneous, and intraperitoneal doses of WR 148999 ranging from 2 to 1024 mg/kg in the Thompson test, median survival times were 8.8, 11.8, and 27.5 days, respectively, compared to 8 days for control animals. Using subcutaneous administration, WR 148999 had a considerably longer duration of action than did artemisinin against P. berghei. WR 148999 did not significantly inhibit cytochrome P450 isozymes CYP 2C9, 2C19, 2D6, 2E1, or 3A4 (IC50 >500 microM) but did inhibit CYP 1A2 with an IC50 value of 36 microM, suggesting that WR 148999 may be metabolized by the latter CYP isozyme. These results combined with previous observations that formulation strategies and incorporation of polar functional groups in a series of WR 148999 analogs both failed to enhance tetraoxane oral antimalarial activity suggest that oral bioavailability of tetraoxane WR 148999 is more likely a function of extensive first-pass metabolism rather than solubility-limited dissolution.
Solitary subcutaneous hydatid cyst: a case report.
Authors: Ok E , SÃ¶zÃ¼er E M
Published: May 2017

In the absence of hepatic and pulmonary involvement, hydatid disease of other organs is extremely rare. In this paper, we report on a patient who had a solitary subcutaneous hydatid cyst in the submandibular region.
Vitamin A supplementation and other predictors of anemia among children from Dar Es Salaam, Tanzania.
Authors: Villamor E , Mbise R , Spiegelman D , Ndossi G , Fawzi W W
Published: May 2017

The associations of hemoglobin, hematocrit, and packed cell volume with socioeconomic factors, malaria, human immunodeficiency virus (HIV) infection, and nutritional status were examined among 687 children admitted to hospital with pneumonia participating in a double blind, placebo-controlled trial of vitamin A supplementation. Children were randomized to receive 2 doses of vitamin A (200,000 IU) or placebo at baseline, and additional doses at 4 and 8 months after discharge from hospital. Hemoglobin levels were measured at enrollment and, on a subset of 161 children, during follow-up. At baseline, hemoglobin concentration was positively associated with the number of possessions in the household, maternal level of education and quality of water supply, and inversely related to malaria infection after controlling for potential confounding variables. Children infected with HIV experienced a significant fall in mean hemoglobin levels over time. The risk of developing severe anemia (< 7 g/dL) during follow-up was lower for children who were breastfed for longer than 18 months as compared to those with less than 6 months of breastfeeding (adjusted prevalence ratio = 0.14, 95% confidence interval [CI] = 0.02, 0.93; P = 0.04), and higher for children over two years of age as compared to 6 to 11 months-old infants (adjusted prevalence ratio = 8.11, 95% CI = 1.2, 55.8; P = 0.03). Children with repeated diagnoses of malaria had 4.1 times the risk of developing severe anemia than did children without the diagnosis (95% CI = 1.3, 13.5; P = 0.02). Vitamin A supplements were associated with an overall nonsignificant reduction of 14% in the risk of developing severe anemia (adjusted prevalence ratio = 0.86, 95% CI = 0.37, 1.99; P = 0.73). We conclude that malaria, HIV infection, low socioeconomic status, and short duration of breastfeeding are strong and independent determinants of adverse hematologic profiles in this population.
Phylogenetic analysis of the rompB genes of Rickettsia felis and Rickettsia prowazekii European-human and North American flying-squirrel strains.
Authors: Moron C G , Bouyer D H , Yu X J , Foil L D , Crocquet-Valdes P , Walker D H
Published: May 2017

The rickettsial outer membrane protein B (rompB) gene encodes the major surface antigens of Rickettsia species. We undertook sequencing and molecular analysis of the rompB gene of Rickettsia felis and a comparison with its homologs in spotted fever group (SFG) and typhus group (TG) rickettsiae, including the complete sequences of two North American flying squirrel strains and two European human strains of Rickettsia prowazekii. We sequenced 5,226 base pairs (bp) of the R. felis rompB, encoding a protein of 1,654 amino acids. We also sequenced 5,015 bp of rompB of the flying squirrel strains, encoding a protein of 1,643 amino acids. Analysis of the R. felis rompB gene sequence showed 10-13% divergence from SFG rickettsiae and 18% divergence from the TG rickettsiae. The rompB of all sequenced strains of R. prowazekii showed an overall similarity of 99.7-99.9%.
Cost-effectiveness analysis of reacquiring and using adenovirus types 4 and 7 vaccines in naval recruits.
Authors: Hyer R N , Howell M R , Ryan M A , Gaydos J C
Published: May 2017

Adenovirus vaccines have controlled acute respiratory disease (ARD) in military recruits since 1971. Vaccine production, however, ceased and new facilities are required. We assessed whether reacquiring and using vaccines in naval recruits is cost-effective. Three policy options were evaluated: no vaccination, seasonal vaccination, and year-round vaccination. Morbidity (outpatient and inpatient), illness costs (medical and lost training), and vaccine program costs (start-up, acquisition, and distribution) were modeled using a decision-analytic method. Results were based on a cohort of 49,079 annual trainees, a winter vaccine-preventable ARD rate of 2.6 cases per 100 person-weeks, a summer incidence rate at 10% of the winter rate, a hospitalization rate of 7.6%, and a production facility costing US$12 million. Compared to no vaccination, seasonal vaccination prevented 4,015 cases and saved $2.8 million per year. Year-round vaccination prevented 4,555 cases and saved $2.6 million. Reacquiring and using adenovirus vaccines seasonally or year-round saves money and averts suffering.
An outbreak of hepatitis E in Northern Namibia, 1983.
Authors: IsaÃ¤cson M , Frean J , He J , Seriwatana J , Innis B L
Published: May 2017

In 1983 in Namibia's Kavango region, epidemic jaundice affected hundreds of people living in settlements lacking potable water and waste disposal facilities. Many were Angolan refugees. The disease, which after investigation was designated non-A non-B hepatitis, was most common in males (72%), in persons aged 15-39 years, and was usually mild except in pregnant women, who incurred 6 (86%) of the 7 fatal infections. Fifteen years later, archived outbreak-associated samples were analyzed. Hepatitis E virus (HEV) was detected by reverse transcription-polymerase chain reaction in feces from 9 of 16 patients tested. Total Ig and IgM to HEV were quantitated in serum from 24 residents of an affected settlement at the outbreak's end: 42% had IgM diagnostic of recent infection and 25% had elevated total Ig without IgM, consistent with past HEV infection. The Namibia outbreak was typical hepatitis E clinically and epidemiologically. This first report of hepatitis E confirmed by virus detection from southern Africa extends the known range of HEV and highlights its risk for refugees.
Arenavirus antibody in rodents indigenous to coastal southern California.
Authors: Bennett S G , Milazzo M L , Webb J P , Fulhorst C F
Published: May 2017

The purpose of this study was to extend our knowledge on the geographic and natural rodent host ranges of New World arenaviruses in California. Sera from 1,094 sigmodontine and 112 murine rodents were tested for antibody against Whitewater Arroyo and Amapari viruses. Antibody was found in 55 (4.6%) of the 1,206 rodents: 4 from northwestern San Diego County, 3 from Los Angeles County, and 48 from Orange County. The antibody-positive rodents included 8 (7.8%) of 103 Neotoma fuscipes, 1 (0.6%) of 180 Neotoma lepida, 1 (3.1%) of 32 Peromyscus boylii, 8 (11.0%) of 73 Peromyscus californicus, 1 (1.2%) of 85 Peromyscus eremicus, 30 (8.5%) of 353 Peromyscus maniculatus, and 6 (2.2%) of 268 Reithrodontomys megalotis. This study provides the first evidence that New World arenaviruses occur in Los Angeles and Orange counties and northwestern San Diego County, and the first evidence that Peromyscus and Reithrodontomys species are naturally infected with New World arenaviruses.
A case-control auditory evaluation of patients treated with artemisinin derivatives for multidrug-resistant Plasmodium falciparum malaria.
Authors: Van Vugt M , Angus B J , Price R N , Mann C , Simpson J A , Poletto C , Htoo S E , Looareesuwan S , White N J , Nosten F
Published: May 2017

The artemisinin derivatives are now used widely in areas with multidrug-resistant Plasmodium falciparum malaria such as Southeast Asia, but concerns remain over their potential for neurotoxicity. Mice, rats, dogs, and monkeys treated with high doses of intramuscular artemether or arteether develop an unusual pattern of focal damage to brain stem nuclei (particularly those involved in auditory processing). To investigate whether a similar toxic effect occurs in patients treated with these compounds, clinical neurologic evaluation, audiometry and early latency auditory evoked responses were measured in a single-blind comparison of 79 patients who had been treated with > or =2 courses of oral artemether or artesunate within the previous 3 years, and 79 age- and sex-matched controls living in a malaria-endemic area on the northwestern border of Thailand. There were no consistent differences in any of these test results between the cases and controls. This study failed to detect any evidence of significant neurotoxicity in patients treated previously with oral artemether or artesunate for acute malaria.
Repeated infection of Aotus monkeys with Plasmodium falciparum induces protection against subsequent challenge with homologous and heterologous strains of parasite.
Authors: Jones T R , Obaldia N , Gramzinski R A , Hoffman S L
Published: May 2017

We evaluated repeated blood-stage infections with Plasmodium falciparum in eight Aotus lemurinus lemurinus monkeys. Over the course of seven infections with 10(4) P. falciparum (the Vietnam Oak Knoll [FVO] strain), the pre-patent period lengthened from 8.2 to 30.8 days; the peak parasitemia decreased from 4.5 x 10(5) to 0 parasites/microl (Challenges 6 and 7), and the requirement for treatment decreased from 100% to 0% (Challenges 3 to 7). Five weeks after the seventh FVO challenge, the eight immune and three naÃ¯ve monkeys received 10(4) parasitized erythrocytes infected with P. falciparum (CAMP strain). The three control animals experienced uncontrolled parasitemias reaching between 4.8 and 7.7 x 10(5) parasites/microl (pre-patency = 6.3 days) and all required drug treatment; six of the eight immune monkeys became parasitemic (pre-patency = 8.8 days), but self-cured. Two of three of the monkeys having the greatest reductions in hematocrit (50-60%) also had the highest parasitemias (approximately 10(4) parasites/microl) before self-curing. Repeated homologous infections induced sterile immunity to homologous challenge; during heterologous challenge the monkeys developed clinically relevant, but not life-threatening, parasitemias and anemia.
Predictors of chloroquine treatment failure in children and adults with falciparum malaria in Kampala, Uganda.
Authors: Dorsey G , Kamya M R , Ndeezi G , Babirye J N , Phares C R , Olson J E , Katabira E T , Rosenthal P J
Published: May 2017

Chloroquine-resistant falciparum malaria is a serious problem in much of sub-Saharan Africa. However, it is desirable to continue to use chloroquine as first-line therapy for uncomplicated malaria where it remains clinically effective. To identify predictors of chloroquine treatment failure, a 14-day clinical study of chloroquine resistance in patients with uncomplicated falciparum malaria was performed in Kampala, Uganda. Among the 258 patients (88% follow-up), 47% were clinical failures (early or late treatment failure) and 70% had parasitological resistance (RI-RIII). Using multivariate analysis, an age less than five (odds ratio [OR] = 3.4, 95% CI = 1.8-6.3) and a presenting temperature over 38.0 degreesC (OR = 2.0, 95% CI = 1.1-3.7) were independent predictors of treatment failure. In addition, patients who last took chloroquine 3 to 14 days prior to study entry were significantly more likely to be treatment failures compared to patients with very recent (less than 3 days) or no recent chloroquine use. In areas with significant chloroquine resistance, easily identifiable predictors of chloroquine treatment failure might be used to stratify patients into those for whom chloroquine use is acceptable and those for whom alternative treatment should be used.
First isolation of the Rift Valley fever virus from Culex poicilipes (Diptera: Culicidae) in nature.
Authors: Diallo M , Lochouarn L , Ba K , Sall A A , Mondo M , Girault L , Mathiot C
Published: May 2017

Following the reemergence of Rift Valley fever (RVF) virus in southeastern Mauritania in 1998, an entomological survey was undertaken in the boundary area in Senegal to assess the extent of the virus circulation. During this study, RVF virus (36 strains) was isolated for the first time from Culex poicilipes in nature. The possible role of Cx. poicilipes as an RVF vector is discussed regarding its biology and ecology.
Markers of enteric inflammation in enteroaggregative Escherichia coli diarrhea in travelers.
Authors: Bouckenooghe A R , Dupont H L , Jiang Z D , Adachi J , Mathewson J J , Verenkar M P , Rodrigues S , Steffen R
Published: May 2017

As part of a traveler's diarrhea study carried out in Guadalajara, Mexico, and Goa, India, we conducted a case control study to evaluate fecal markers of enteric inflammation in three groups. Forty-five cases of enteroaggregative Escherichia coli (EAEC) diarrhea were compared to 56 controls with enterotoxigenic E. coli (ETEC) diarrhea, and 126 controls with diarrhea without identifiable pathogens. For EAEC cases we found fecal leukocytes, occult blood, and lactoferrin in 13 (28.9%), 14 (31.1%), and 27 (60.0%) patients, respectively; for ETEC controls they were 15 (26.8%), 16 (28.6%), and 15 (26.8%) respectively; and for patients without identifiable pathogens 19 (15.1%), 34 (27.0%) and 27 (21.4%) were seen for the presence of a positive fecal lactoferrin test in EAEC cases was statistically significant compared to both control groups. The study provides evidence that EAEC infection is associated with an intestinal inflammatory response.
A possible role of bats as a blood source for the Leishmania vector Lutzomyia longipalpis (Diptera: Psychodidae).
Authors: Lampo M , Feliciangeli M D , MÃ¡rquez L M , Bastidas C , Lau P
Published: May 2017

Some evidence suggests that bats may provide an alternative blood source for Lutzomyia longipalpis, the main vector of American visceral leishmaniasis. Feeding trials were conducted to determine whether L. longipalpis feeds on captive bats. The high feeding success indicated that L. longipalpis is capable of feeding on at least four species of bats. Implications for the epidemiology of leishmaniases are discussed.
Epidemiology 1, 2, 3: study and sample design.
Authors: Hussein M H , El-Sayed M K , Talaat M , El-Badawy A , Miller F D
Published: May 2017

Bad sample designs and selection bias have plagued studies on schistosomiasis, and as a result some believe that schistosomiasis is too focal, making it difficult to draw reliable samples. The Epidemiology 1, 2, 3 (EPI 1, 2, 3) sample design, although complex, demonstrates that sampling theory is readily applicable to epidemiologic studies of schistosomiasis. The EPI 1, 2, 3 sampling scheme was designed to achieve the smallest feasible standard errors given EPI 1, 2, 3 objectives and certain logistical constraints. The sample design is a multi-stage selection of villages (ezbas, which were stratified by size) and households within each of 9 purposely selected Egyptian governorates. Villages and households were systemically selected from census frames. The sampling of ezbas was especially difficult because of the lack of complete sampling frames and their wide variation in population size. Ultimately, ezbas were stratified by size and then randomly selected from each stratum. Sample sizes for villages and ezbas and individuals within ezbas were calculated based on EPI 1 and 2 objectives, respectively. No re-selection was made for non-respondents. A 20% subsample of the full sample was drawn for clinical and ultrasonographic examinations. The sample selected from individual governorates closely parallel the age structure of the 1986 census of the respective rural populations. Details of the study design and related methods are given below.
The epidemiology of schistosomiasis in Egypt: Qena governorate.
Authors: Hammam H M , Zarzour A H , Moftah F M , Abdel-Aty M A , Hany A H , El-Kady A Y , Nasr A M , Abd-El-Samie A , Qayed M H , Mikhail N N , Talaat M , Hussein M H
Published: May 2017

Qena is the southernmost governorate of Egypt included in the Epidemiology 1, 2, 3 national study. A probability sample selected 17,822 individuals from 2,950 households in 34 ezbas and 10 villages from a total rural target population of 1,731,252 (based on the most recent 1986 census of the population by the Egyptian Central Agency for Public Mobilization And Statistics). Parasitologic examination of urine and stool were made for Schistosoma haematobium and S. mansoni, respectively, and physical and ultrasound examinations were made on a 20% subsample. The overall estimated prevalence of S. haematobium was 4.8 +/- 0.7% (+/-SE) and geometric mean egg count (GMEC) was 7.0 ova per 10 ml of urine. Considerable variation in prevalence was observed between the villages and ezbas, ranging from 0.0% to 20%, with the smaller ezbas having a slightly higher overall prevalence. The age- and sex-specific patterns of S. haematobium showed typical peak prevalence in early adolescence, with males having a higher prevalence than females. A history of hematuria was associated with current infection (odds ratio = 3.6, 95% confidence interval = 2.32-5.63). Hepatomegaly and splenomegaly determined by physical examination present in 7.9% and 3.0%, respectively. Ultrasonography-determined hepatomegaly of the left liver lobe was found in 10.1%. Ultrasonography-detected hepatomegaly in both the left and right lobes increased in prevalence from approximately 5% in children to 15-20% in adults. The prevalence of ultrasonography-detected splenomegaly increased slightly with age. Grade III periportal fibrosis was detected in only 2 individuals in the sample. Bladder wall lesions and obstructive uropathy were also very infrequent. Other associations with these measures are given. Most villages and ezbas had an S. mansoni prevalence of less than 1%. The exception was Nag'a El-Sheikh Hamad, where the prevalence was 10.3 +/- 0.5% (GMEC = 57.4 +/- 2.6). Two other communities also had a prevalence >1% (Ezbet Sarhan and Kom Heitin).
Pharmacokinetics of UMF-078, a candidate antifilarial drug, in infected dogs.
Authors: Theplertboon R , Fleckenstein L , Dzimianski M T , McCall J W
Published: May 2017

The pharmacokinetics of the filaricidal benzimidazole compounds UMF-078 and UMF-289 were evaluated in beagle dogs experimentally infected with Brugia pahangi. Twenty-four infected microfilaremic beagles were selected and randomly allocated into 4 treatment groups of 6 dogs each: oral (PO) UMF-078, PO UMF-289 (the HCl salt form of UMF-078), intramuscular (IM) UMF-078, and untreated controls. Equivalent doses of 50 mg/kg of the free base were given twice a day for 3 days to the 3 groups of treated dogs. Oral absorption is rapid compared with IM dosing; the absorption half-life (K01-HL) for the IM treatment is approximately 14 hr compared with 1 and 2 hr for the PO regimen of salt and free base forms, respectively. The elimination half-lives (K10-HL) for the PO regimens are 13 and 15 hr for the salt and free base forms, respectively. Because of sustained absorption following IM dosing, the K10-HL is prolonged. In contrast to oral administration, IM dosing of UMF-078 provides sustained, relatively low plasma drug levels, with good tolerance and efficacy.
Genotypic analysis of hepatitis C virus in blood donors in Indonesia.
Authors: Inoue Y , Sulaiman H A , Matsubayashi K , Julitasari  , Iinuma K , Ansari A , Laras K , Corwin A L
Published: May 2017

A study was conducted to describe the genetic diversity of hepatitis C virus (HCV) in a population of positive blood donors from throughout Indonesia. Repeat analysis by reverse transcription-polymerase chain reaction (RT-PCR) of 102 anti-HCV positive samples showed that 67 gave HCV-specific positive signals by the PCR for the 5'-untranslated genomic region of HCV. Further genotypic analysis on 64 HCV RNA-positive samples indicated that 57 belonged to the following individual genotypes: 1a, 1b, 2a, 2b, and 3b. The predominant HCV genotypes in this donor population were 1b (57.8%), 2a (17.2%), and 3b (10.9%). The core sequences of the 4 indeterminate samples when aligned with published sequences of various HCV genotypes showed a range of homology from 16.16% to 78.67%. Comparative analysis of genotypic representation from other anti-HCV-positive study populations, including polytransfused pediatric and adult renal dialysis groups, is now being carried out to determine the potential genotypic association with mechanistic HCV spread.
Morbidity associated with Schistosoma mansoni infection determined by ultrasound in an endemic area of Brazil, Caatinga do Moura.
Authors: De Jesus A R , Miranda D G , Miranda R G , AraÃºjo I , MagalhÃ£es A , Bacellar M , Carvalho E M
Published: May 2017

Morbidity in schistosomiasis is caused by a granulomatous response to Schistosoma mansoni eggs deposited in peripheral portal veins. Ultrasonography has been useful to assess the impact of control programs on the prevalence of hepatic fibrosis. In the present study, ultrasonographic criteria proposed by the World Health Organization were used to classify the degree of hepatic fibrosis in 164 schistosomiasis patients from an endemic area of Brazil. The majority of subjects (89%) had degree I or II hepatic fibrosis. Periportal tract thickness, portal vein diameter, splenic vein diameter, and spleen size were positively correlated (P < 0.01). Ultrasonography was repeated on 21 patients one year later and hepatic fibrosis had progressed in 17. Ultrasonography was performed after treatment on 39 subjects and periportal fibrosis had regressed in 27.