bluuebunny/crossref_metadata_2025 huggingface dataset:
Cultivation and characterization of stable Leishmania guyanensis complex axenic amastigotes derived from infected U937 cells.
Authors: Puentes F , Diaz D , Hoya R D , GutÃ­errez J A , Lozano J M , Patarroyo M E , Moreno A
Published: May 2017

The study of the differential regulation of several genes, in both Leishmania parasite life cycle forms, has been simplified by the development of in vitro axenic amastigote culture. Different reports have described extracellular amastigote production and maintenance from several Leishmania spp. A general approach to induce amastigote-like transformation includes progressive pH and temperature changes. Production of axenic amastigotes in continuous cultures using amastigotes recovered from macrophages is described in this report. Leishmania (Viannia) panamensis (M/HOM/PA/71/LS94) and Leishmania (V). guyanensis (M/HOM/BR/75/M4147) intracellular amastigotes were recovered from the human macrophage-like U937 cell line previously infected with promastigotes. The parasites were immediately adapted for growth and kept as axenic amastigotes at 34 degrees C and acidic pH. These organisms were able to infect macrophage cell lines, maintain amastigote morphologic features, and express stage-specific transcripts. The relevance of axenic amastigotes in characterizing virulence factors in American leishmaniasis is discussed.
Short report: failure to select for chloroquine- or mefloquine-resistant Plasmodium berghei through drug pressure in Anopheles stephensi mosquitoes.
Authors: Coleman R E , Song G H , Wirtz R A
Published: May 2017

We investigated whether chloroquine- or mefloquine-resistant Plasmodium berghei could be selected through drug pressure applied during continuous cyclical transmission in Anopheles stephensi mosquitoes. Mosquitoes were infected by feeding them on mice previously inoculated with a drug-sensitive clone of P. berghei ANKA. Mosquitoes ingested mefloquine or chloroquine with the infectious blood-meal, or by feeding on a drug-treated (uninfected) mouse 4 or 10 days after the infectious blood-meal. Twenty-two days after being infected, mosquitoes transmitted sporozoites to uninfected mice. Blood from these animals was used to infect naive mice that were then used to reinitiate the mouse/mosquito/mouse cycle. A total of 20 passages through mosquitoes were completed while under drug pressure. Drug-resistance levels were assessed in the initial clone and after 20 passages through mosquitoes. None of 18 "sub-clones" of parasites showed significant increases in chloroquine or mefloquine resistance, suggesting that exposure of sporogonic stage Plasmodium to chloroquine or mefloquine will not result in the development of drug resistance.
IgE deposition in brain microvessels and on parasitized erythrocytes from cerebral malaria patients.
Authors: Maeno Y , Perlmann P , PerlmannH  , Kusuhara Y , Taniguchi K , Nakabayashi T , Win K , Looareesuwan S , Aikawa M
Published: May 2017

Postmortem brain tissues of 21 cerebral malaria cases were obtained in Myanmar and Vietnam. The tissues were examined by light microscopy and by an immunohistochemical method. Brain microvessels (capillaries and venules) were examined for the presence of immunoglobulins IgE and IgG, Plasmodium falciparum antigen, and parasitized erythrocytes (PRBC). Deposition of IgE, IgG, and P. falciparum antigen was observed in the microvessels from all specimens examined. Sequestered PRBC in the microvessels were positive for IgG in all 21 cases and for IgE in six cases. In the latter cases, the percentage of microvessels with sequestered PRBC was > 50%, with the frequency of IgE-positive cells ranging from 42% to 52%. In contrast, in five cases that were only weakly positive for IgE, the percentage of microvessels with sequestered PRBC was remarkably low (< 1%). These data indicate that the degree of deposition of IgE in microvessels and on PRBC from cerebral malaria patients correlated with that of PRBC sequestration. As IgE-containing immune complexes are known to induce local overproduction of tumor necrosis factor-alpha (TNF-alpha), a major pathogenic factor in cerebral malaria, IgE may contribute to the pathogenesis of this severe disease.
Predisposition to urinary tract epithelial metaplasia in Schistosoma haematobium infection.
Authors: Hodder S L , Mahmoud A A , Sorenson K , Weinert D M , Stein R L , Ouma J H , Koech D , King C H
Published: May 2017

Although there is strong epidemiologic evidence linking Schistosoma haematobium infection with carcinoma of the bladder, the utility of cytologic screening for urinary tract cancer has not been critically evaluated in S. haematobium-endemic populations. The present cross-sectional study examined urine cytology findings among 1,014 residents (ages 1 to 91) of the S. haematobium-endemic Msambweni area of Coast Province, Kenya. Among 705 evaluable cytology specimens, prevalence of inflammation (39%), hyperkeratosis (30%), metaplasia (33%), and frank atypia (0.4%) was notably higher than in previously studied, non-endemic populations. Overall, S. haematobium infection was strongly associated with increased risk for cytologic abnormality (> 2.8-fold relative risk of metaplasia or hyperkeratosis; P < 0.001). Age-group analysis confirmed parallel increases in metaplasia and S. haematobium infection prevalence early in life (from age I to 15 for both boys and girls). However, above age 20, metaplasia prevalence persisted at 33-45% prevalence despite a decline in infection prevalence and intensity. Prevalence of advanced (moderate or severe) metaplasia showed two age-related peaks: the first at 10-14 years of age (at the time of peak infection), and the second among subjects > or = 60 years old. No cancers were detected in the study population either on cytology or on follow-up ultrasound examination. These data suggest an age-dependent progression of cellular abnormalities in the urinary epithelium that is associated with chronic S. haematobium infection, which becomes independent of concurrent infection intensity as subjects grow older. Implications for cancer screening are discussed.
Dynamics of P. falciparum gametocytemia in symptomatic patients in an area of intense perennial transmission in Tanzania.
Authors: Akim N I , Drakeley C , Kingo T , Simon B , Senkoro K , Sauerwein R W
Published: May 2017

We investigated the dynamics of Plasmodium falciparum gametocytemia in symptomatic patients attending a local dispensary in the Kilombero district, Tanzania. Consenting individuals aged one and above, with varying asexual and sexual parasitemias were treated appropriately and asked to return weekly for 28 days. Gametocyte prevalence was highest on Day 7 of follow-up in all age groups (overall 30.5%). Multifactorial analysis showed that young age (chi2 = 18.4; P = 0.004), high asexual parasitemia on presentation (chi2 = 19.4; P = 0.0007) and gametocyte positivity on presentation (chi2 = 29.4; P = 0.001) were all significantly associated with the presence of gametocytes on Days 7 and 14 of follow-up. High presentation of asexual parasitemia alone was positively correlated with higher gametocyte densities on both days of follow-up (F4, 297 = 2.0; P = 0.049). Gametocyte incidence rates decreased significantly with age (chi2 = 7.6, P < 0.005). In summary, in this group of chloroquine-treated individuals, gametocyte prevalence and incidence rates decreased with age, while densities remained relatively constant.
An outbreak of fulminant hepatitis delta in the Waorani, an indigenous people of the Amazon basin of Ecuador.
Authors: Manock S R , Kelley P M , Hyams K C , Douce R , Smalligan R D , Watts D M , Sharp T W , Casey J L , Gerin J L , Engle R , Alava-Alprecht A , MartÃ­nez C M , Bravo N B , Guevara A G , Russell K L , Mendoza W , Vimos C
Published: May 2017

An outbreak of delta hepatitis occurred during 1998 among the Waorani of the Amazon basin of Ecuador. Among 58 people identified with jaundice, 79% lived in four of 22 Waorani communities. Serum hepatitis B surface antigen (HBsAg) was found in the sera of 54% of the jaundiced persons, and 14% of asymptomatic persons. Ninety-five percent of 105 asymptomatic Waorani had hepatitis B core (HBc) IgG antibody, versus 98% of 51 with jaundice. These data confirm that hepatitis B virus (HBV) infection is highly endemic among the Waorani. Sixteen of 23 (70%) HBsAg carriers identified at the onset of the epidemic had serologic markers for hepatitis D virus (HDV) infection. All 16 were jaundiced, where as only two of seven (29%) with negative HDV serology were jaundiced (P = .0006). The delta cases clustered in families, 69% were children and most involved superinfection of people chronically infected with HBV. The data suggest that HDV spread rapidly by a horizontal mode of transmission other than by the sexual route.
Effect of dose increase or cimetidine co-administration on albendazole bioavailability.
Authors: Schipper H G , Koopmans R P , Nagy J , Butter J J , Kager P A , Van Boxtel C J
Published: May 2017

The low bioavailability of albendazole affects the therapeutic response in patients with echinococcosis. Cimetidine co-administration is reported to improve bioavailability. To analyze the assumed dose-dependent bioavailability of albendazole, we administered 5 to 30 mg/kg albendazole to 6 male volunteers in a randomized cross-over study. To assess the effect of cimetidine (10 mg/kg twice daily), the drug was given with albendazole (20 mg/kg). A dose-dependent bioavailability was not observed. This was due to inter-individual variability of the maximal concentration (Cmax 38%-72%) of albendazole sulphoxide (ABZSX), the active metabolite of albendazole. Cmax was 0.21+/-0.14 mg/L after 5 mg/kg and 0.39+/-0.19 mg/L after 30 mg/kg albendazole (P = 0.217). Cimetidine tended to decrease Cmax by 52% (P = 0.109) and significantly inhibited ABZSX breakdown as indicated by the prolongation of ABZSX elimination half-life from 7.4+/-3.3 hr to 19.0+/-11.7 hr (P = 0.028). Remarkably, the inter-individual variability of Cmax was significantly lower during cimetidine co-administration: 14% versus 72%.
Atovaquone plus proguanil versus halofantrine for the treatment of imported acute uncomplicated Plasmodium falciparum malaria in non-immune adults: a randomized comparative trial.
Authors: Bouchaud O , Monlun E , Muanza K , Fontanet A , Scott T , Goetschel A , Chulay J D , Le Bras J , Danis M , Le Bras M , Coulaud J P , Gentilini M
Published: May 2017

In endemic zones, the atovaquone-proguanil (AP) combination is well tolerated and effective in treating acute, uncomplicated malaria. Trials involving non-immune patients are lacking, however. We conducted a randomized, multicenter open-label trial to determine the efficacy and tolerability of the AP combination (1,000 mg + 400 mg once daily for 3 days) in comparison with halofantrine (HF) (1,500 mg in 3 doses) in non-immune adults with imported uncomplicated Plasmodium falciparum malaria. Follow-up visits were programmed on Days 7, 14, 21, 28, and 35 after hospital discharge. Out of 48 patients enrolled in the study, 41 were assessable for the cure rate (21 in the AP group and 20 in the HF group). All the patients were cured. The mean parasite clearance time was longer (63+/-23 hours) in the AP group than in the HF group (48+/-15 hours) (P = 0.02). The frequency of gastrointestinal adverse events was higher in the AP group. No noteworthy electrocardiographic changes were observed, particularly in the QTc interval. The AP combination appears to be a valuable alternative treatment in non-immune adults.
Self-testing for falciparum malaria with antigen-capture cards by travelers with symptoms of malaria.
Authors: Whitty CJM  , Armstrong M , Behrens R H
Published: May 2017

Kits for self-diagnosis of malaria by travelers in remote areas have been advocated. Antigen-capture test cards work reliably in the laboratory, but there is limited data regarding self-testing by ill patients. One hundred and fifty-three symptomatic patients presenting for a malaria test attempted self-diagnosis using these kits. Nine percent failed to perform a valid test. Against blood-film proven malaria, specificity was 97% (95% confidence intervals [CI] 93-99%) and sensitivity 95% (95% CI 74-99%). Although these results are encouraging, technical problems need to be addressed and test sensitivity proven by additional field-testing before this technology can be marketed to travelers.
Isoenzyme characterization of Leishmania isolates from Lebanon and Syria.
Authors: Knio K N , Baydoun E , Tawk R , Nuwayri-Salti N
Published: May 2017

Leishmania parasites were isolated from 22 Lebanese and 5 Syrian patients with active skin lesions for whom the diagnosis was confirmed by histopathological examination. The isolates were characterized by starch gel electrophoresis and analysis of 13 enzyme systems. Eight Old-World reference strains were used for comparison. One Syrian isolate belonged to Leishmania major, and four Syrian and two Lebanese to Leishmania tropica. Contrary to expectations, the majority of Lebanese isolates were related to the Leishmania donovani complex, and more particularly Leishmania infantum.
Dengue virus infects human endothelial cells and induces IL-6 and IL-8 production.
Authors: Huang Y H , Lei H Y , Liu H S , Lin Y S , Liu C C , Yeh T M
Published: May 2017

In this study dengue virus (DV) was found to infect primary endothelial cells derived from human umbilical cord veins (HUVEC) and alter their cytokine production. Dengue virus infection of HUVEC was confirmed by an increase in plaque-forming units in the culture supernatant and by immunofluorescence assay. HUVEC produced large amounts of interleukin (IL)-6 and IL-8 but not IL-1beta after DV infection. Both the replication of DV and the production of IL-6 and IL-8 by HUVEC after DV infection were inhibited by ribavirin, an antiviral synthetic guanosine analogue. Additionally, increased serum levels of IL-6 and IL-8 were observed in patients with dengue hemorrhagic fever but not dengue fever. Therefore, our results suggest that endothelial cells can be a target for DV infection, and that DV-induced IL-6 and IL-8 production by endothelial cells may contribute to the pathogenesis of dengue hemorrhagic fever.
A trial for a DNA diagnosis of Plasmodium vivax malaria recently reemerging in the Republic of Korea using microtiter plate hybridization assay.
Authors: Chai J Y , Park Y K , Guk S M , Oh K H , Oh M D , Lee S H , Kim H S , Wataya Y
Published: May 2017

The polymerase chain reaction-based microtiter plate hybridization (PCR-MPH) assay was utilized for a DNA diagnosis of Plasmodium vivax malaria, which has recently reemerged in the Republic of Korea. The subjects were 18 parasite-proven patients and 5 healthy controls. Follow-up blood samples were collected from 4 patients after a standard course of treatment. Polymerase chain reaction and electrophoresis of all the patients' blood showed a prominent band at the 138 base pair area, but not in the controls or after treating the patients. Hybridization of the PCR products with known species-specific probes of the 18S rRNA of various malaria species revealed strong positive reactions against the Plasmodium vivax-specific probe (absorbance 1.30-1.90 at 405 nm) in all of the patients. The absorbance was positively correlated with the degree of blood parasitemia, but with a borderline significance. Sequencing of the probe region of the Korean P. vivax revealed no significant variations from the typical P. vivax. The results show that the PCR-MPH is a highly useful technique for the DNA diagnosis of Korean vivax malaria.
Paper chromatography hybridization: a rapid method for detection of Onchocerca volvulus DNA amplified by PCR.
Authors: Zhang S , Li B W , Weil G J
Published: May 2017

Prior studies have shown that Onchocerca volvulus DNA can be detected in skin snips and in black flies after polymerase chain reaction (PCR) with primers specific for repeated "O-150" DNA sequences. We have adapted a paper chromatography hybridization assay (PCHA) to detect amplified O-150 DNA and compared this method to two established methods, namely agarose gel electrophoresis (AGE) and hybridization enzyme-linked immunosorbent assay (ELISA). The minimum amounts of purified O-150 DNA detected by PCHA, AGE, and ELISA were 5, 10, and 2 ng, respectively. The three methods had similar estimated sensitivities for detecting O. volvulus DNA amplified from skin snips from African subjects with onchocerciasis (88%, 84%, and 91%, respectively). No false positive results were observed with skin snips from uninfected control subjects. The paper chromatography hybridization assay detects PCR products in 30 minutes without electricity or special equipment. This technology brings DNA detection a step closer to widespread use in field settings.
Antibody to sin nombre virus in rodents associated with peridomestic habitats in west central Montana.
Authors: Kuenzi A J , Douglass R J , White D , Bond C W , Mills J N
Published: May 2017

Most human cases of hantavirus pulmonary syndrome are acquired in the peridomestic environment, yet studies of the ecology and infection dynamics in the reservoir host, the deer mouse (Peromyscus maniculatus), have focused on sylvan populations. We describe a 2.5-year study of hantavirus infection in rodents associated with peridomestic habitats in west central Montana. Antibodies reactive with Sin Nombre virus (SNV) were found in five species. Overall SNV antibody prevalence was highest among deer mice (25% of individuals tested). As has been demonstrated for sylvan populations, the antibody-positive component of the deer mouse population consisted of a higher proportion of adults and males. However, the prevalence of antibodies to SNV was higher in this study than has been reported in most sylvan studies. The average monthly proportion of deer mouse blood samples with antibodies to SNV ranged from approximately 20% to 25% and was highest in the late spring/early summer. The higher SNV antibody prevalence in peridomestic compared with sylvan settings may be related to behavioral differences and/or potentially longer survival of the virus deposited inside buildings. Peridomestic settings presented higher concentrations of virus and may present a higher risk of human infection than do sylvan settings.
The increasing burden of infectious diseases on hospital services at St Mary's Hospital Lacor, Gulu, Uganda.
Authors: Accorsi S , Fabiani M , Lukwiya M , Onek P A , Mattei P D , Declich S , _ _
Published: May 2017

To evaluate the impact of infectious diseases on hospital services in Northern Uganda, a retrospective analysis of discharge records concerning 70,304 inpatients admitted to the Lacor Hospital (Gulu, Uganda) during the period 1992-1997 was performed. Children less than five years old represented 46.5% of the admissions, and the burden of infectious diseases on pediatric admissions increased over time, especially due to malaria and measles. Infectious diseases accounted for 7 of the 10 leading causes of admission. The most frequent cause was malaria (21.8% of total). The second leading infectious disease resulting in admission was respiratory tuberculosis (6.2%); given the long hospital stay, this is the most important disease in terms of hospital bed days (24.6%). Infectious diseases have represented a progressively heavy burden on hospital services, mostly due to pediatric admissions. Respiratory tuberculosis and malaria represent nearly one-third of the overall burden in terms of hospital bed days.
Randomized intervention study comparing several regimens for the treatment of moderate anemia among refugee children in Kigoma Region, Tanzania.
Authors: Tomashek K M , Woodruff B A , Gotway C A , Bloland P , Mbaruku G
Published: May 2017

Anemia-specific mortality was markedly elevated among refugee children < 5 years of age in Tanzania. In a randomized, double-blind study, 215 anemic children were initially treated for malaria and helminth infection and then received 12 weeks of thrice-weekly oral iron and folic acid. Group I received placebo and chloroquine treatment for symptomatic malaria infection (i.e., no presumptive anti-malarial treatment given). Group II received placebo and monthly presumptive treatment with sulfamethoxazole-pyrimethamine (SP). Group III also received monthly SP and thrice-weekly vitamins A and C (VAC). Mean hemoglobin concentration increased from 6.6 to 10.2 g/dL, with no significant differences among groups. Group II had lower mean serum transferrin receptor levels (TfR) than group I [P = 0.023]. A greater proportion of participants in group III had normal iron stores (TfR < 8.5 microg/ mL) than in group II [P = 0.012]. Initial helminth and malaria treatment, followed by thrice-weekly iron and folic acid supplements resulted in increased hemoglobin levels. Monthly SP and thrice-weekly VAC contributed to improve iron stores. Monthly SP may have a role in situations where asymptomatic disease is prevalent or where access to care is limited. Because administration of VAC also hastened recovery of iron stores over administration of monthly SP alone, health care personnel could add VAC to the treatment for moderate anemia if maximum recovery of iron stores is desired.
Identification of frequently recognized dimorphic T-cell epitopes in plasmodium falciparum merozoite surface protein-1 in West and East Africans: lack of correlation of immune recognition and allelic prevalence.
Authors: Lee E A , Flanagan K L , Odhiambo K , Reece W H , Potter C , Bailey R , Marsh K , Pinder M , Hill A V , Plebanski M
Published: May 2017

The merozoite surface protein-1 (MSP1) is the most studied malaria blood-stage vaccine candidate. Lymphokines such as interferon gamma (IFN-gamma) and interleukin 4 (IL-4) may mediate blood-stage specific protection. Here we identify Plasmodiumfalciparum MSP1 T-cell epitopes capable of rapid induction of IFN-gamma and/or IL-4 from peripheral blood mononuclear cells of East and West African donors. Both allelic forms of these novel MSP1 T-cell epitopes were stimulatory. An unusually high numbers of Gambian responders (> 80%) to these epitopes were observed, suggesting that MSPI reactivity may have been underestimated previously in this population. Surprisingly, IFN-gamma responses to allelic T-cell epitopes failed to correlate with differential antigenic exposure in The Gambia compared to Kenya. These results suggest an unexpected level of immunoregulation of IFN-gamma response with variable allelic T-cell reactivity independent of the level of antigenic exposure. Further analysis of the mechanisms determining this response pattern may be required if vaccines are to overcome this allelic reactivity bias in malaria-exposed populations.
Blood-brain barrier function in cerebral malaria in Malawian children.
Authors: Brown H , Rogerson S , Taylor T , Tembo M , Mwenechanya J , Molyneux M , Turner G
Published: May 2017

Cerebral malaria (CM) is a serious complication of Plasmodium falciparum infection. Binding of parasitized erythrocytes to cerebral endothelium plays a key role in disease pathogenesis. Central nervous system signs and symptoms (coma, seizures, raised intracranial pressure) predominate in African children, whereas in adults, multiorgan system failure is more common. In this study we investigated whether changes in blood-brain barrier (BBB) structure and function are compatible with the signs and symptoms observed in Malawian children with CM. Immunohistochemistry on autopsy brain tissues from eight cases of CM showed activation of endothelial cells and macrophages, and disruption of endothelial intercellular junctions in vessels containing sequestered parasitized erythrocytes, but no gross leakage of plasma proteins. Examination of the partition of albumin between circulating plasma and the cerebrospinal fluid from 72 cases of CM showed subtle but measurable changes compatible with impaired BBB function in malaria. These findings suggest that BBB breakdown occurs in areas of parasite sequestration in CM in African children.
Short report: seroprevalence of Taenia solium cysticercosis in pigs in Bahia State, northeastern Brazil.
Authors: Sakai H , Barbosa H V , Silva E M , Schlabitz F O , Noronha R P , Nonaka N , Franke C R , Ueno H
Published: May 2017

To determine the prevalence and etiologic factors of Taenia solium cysticercosis in pigs in the state of Bahia, northeastern Brazil, we performed serological surveys in Salvador, the capital of the state, and in two local towns, Santo Amaro and JequiÃ©. Residents raising free-roaming pigs in the study areas were randomly selected. Sera were obtained from the pigs and examined by the enzyme-linked immunoelectrotransfer blot assay (EITB). The prevalence of antibodies to T. solium was 4.4% (2 of 45) in Salvador, 3.2% (3 of 93) in Santo Amaro, and 23.5% (24 of 102) in JequiÃ©. A significantly high seroprevalence in JequiÃ© was associated with poor sanitary conditions, such as an open sewer system and no inspection process of pork before marketing.
Tonate virus infection in French Guiana: clinical aspects and seroepidemiologic study.
Authors: Talarmin A , Trochu J , Gardon J , Laventure S , Hommel D , Lelarge J , Labeau B , Digoutte J P , Hulin A , Sarthou J L
Published: May 2017

Two recent cases of human infection with Tonate virus, one of which was a fatal case of encephalitis, have renewed interest in these viruses in French Guiana. The clinical aspects of confirmed and probable cases of infection with this virus indicate that it has pathogenic properties in humans similar to those of other viruses of the Venezuelan equine encephalitis complex. To determine the prevalence of antibodies to Tonate virus in the various ethnic groups and areas of French Guiana, 3,516 human sera were tested with a hemagglutination inhibition test. Of these, 11.9% were positive for the virus, but significant differences in seroprevalence were found by age, with an increase with age. After adjustment for age, significant differences were found between places of residence. The prevalence of antibody to Tonate virus was higher in savannah areas, especially in the Bas Maroni (odds ratio [OR] = 22.2, 95% confidence interval [CI] = 15.2-32.4) and Bas Oyapock areas (OR = 13.4; 95% CI = 9.8-18.4). The ethnic differences observed in this study were due mainly to differences in place of residence, except that whites were significantly less frequently infected than other ethnic groups. This study indicates that Tonate virus infection is highly prevalent in French Guiana, especially in savannah areas.
Automated detection of malaria pigment in white blood cells for the diagnosis of malaria in Portugal.
Authors: HÃ¤nscheid T , Melo-Cristino J , Pinto B G
Published: May 2017

A novel automated method (Cell-Dyn 3500) allows malaria diagnosis by detecting malaria pigment in white blood cells during routine full blood counts. In Portugal, 174 samples from 148 patients who presented to the emergency department were analyzed. Compared with microscopy the sensitivity was 95% and the specificity was 88%. In 5 cases, false-positive Cell-Dyn 3500 results were from patients who had a recent history of treated malaria, indicating that the method may remain positive during convalescence. Six patients were diagnosed due to the changes observed with the automated method only, because clinicians had not requested malaria smears. This instrument appears to provide a promising method for the diagnosis of malaria, especially where automated full blood counts are routine in the work-up of febrile patients.
Pathogenic aspects of pyogenic liver abscess associated with experimental schistosomiasis.
Authors: Teixeira R , Coelho P M , Brasileiro Filho G , Azevedo Junior G M , Serufo J C , Pfeilsticker F J , Abreu F P , Costa C P , Santa Cecilia G D , Lambertucci J R
Published: May 2017

Schistosomiasis mansoni infection that occurs concurrently with Staphylococcus aureus bacteremia favors the formation of pyogenic liver abscess. The present experimental study in mice evaluated the following aspects of the relationship between infection with Schistosoma mansoni and liver abscess caused by S. aureus: a) the role of the eggs of S. mansoni in the genesis of the abscesses; b) the influence of different phases of schistosomiasis in the development of liver abscesses; and c) the effect of the treatment of schistosomiasis on the development of the abscesses. Macroscopic and histopathological study showed multiple liver abscesses around granulomas of S. mansoni in the acute and chronic phases of schistosomiasis. Treatment of acute schistosomiasis before experimentally-induced bacteremia did not prevent the formation of liver abscess. The study findings indicate that granulomas around S. mansoni eggs and worms lodged in the liver provide a focus and substrate for pyogenic abscesses caused by S. aureus.
Sylvatic transmission of arboviruses among Bornean orangutans.
Authors: Wolfe N D , Kilbourn A M , Karesh W B , Rahman H A , Bosi E J , Cropp B C , Andau M , Spielman A , Gubler D J
Published: May 2017

Wild populations of nonhuman primates live in regions of sylvatic arbovirus transmission. To assess the status of arbovirus transmission in Bornean forests and the susceptibility of wild orangutans to arboviral infection, blood samples of wild orangutans, semi-captive orangutans, and humans were examined. Samples were tested by plaque reduction neutralization test for antibodies to viruses representing three families (Flaviviridae, Alphaviridae, and Bunyaviridae), including dengue-2, Japanese encephalitis, Zika, Langat, Tembusu, Sindbis, Chikungunya, and Batai viruses. Both wild and semi-captive orangutan groups as well as local human populations showed serologic evidence of arbovirus infection. The presence of neutralizing antibodies among wild orangutans strongly suggests the existence of sylvatic cycles for dengue, Japanese encephalitis, and sindbis viruses in North Borneo. The present study demonstrates that orangutans are susceptible to arboviralinfections in the wild, although the impact of arboviral infections on this endangered ape remain unknown.
Antioxidant status and acute malaria in children in Kampala, Uganda.
Authors: Metzger A , Mukasa G , Shankar A H , Ndeezi G , Melikian G , Semba R D
Published: May 2017

Although antioxidant status has been implicated in the pathogenesis of malaria, these factors need further characterization. A longitudinal study was conducted involving 273 children 1-10 years of age with acute, uncomplicated malaria in Kampala, Uganda. Plasma vitamin A, carotenoids, and vitamin E were measured at enrollment and on day 7. Malaria parasitemia was measured at enrollment, on day 3, and on day 7. Malaria parasitemia had completely cleared in 57.1% and 85.3% of children by day 3 and day 7, respectively. Plasma vitamin A, alpha-carotene, beta-carotene, lycopene, lutein/zeaxanthin, and vitamin E were depressed at enrollment and increased by day 7. Multivariate analyses showed that higher plasma lycopene concentrations at enrollment were associated with clearance of parasitemia between enrollment and day 3 (odds ratio = 1.46, 95% confidence interval = 1.07-2.06, per 0.10 micromol/L of lycopene). This study suggests that children with acute malaria have depressed plasma concentrations of antioxidants, and that higher plasma lycopene is associated with more rapid clearance of malaria parasitemia.
Experimental infection of Neotoma albigula (Muridae) with Whitewater Arroyo virus (Arenaviridae).
Authors: Fulhorst C F , Milazzo M L , Bradley R D , Peppers L L
Published: May 2017

The Whitewater Arroyo virus (WWA) is a newly described North American arenavirus. The purpose of this study was to elucidate the biology of this virus in its natural rodent host, Neotoma albigula (white-throated woodrat). Thirteen adult, 7 juvenile, and 8 newborn woodrats each were inoculated subcutaneously with 1,000 cell culture infectious dose50 of the WWA virus prototype strain AV 9310135. All 28 animals became infected (as measured by the recovery of infectious virus and/or seroconversion) and no overt illness was associated with infection. Infection and virus shedding in the adult animals were transient (less than 59 days) whereas virus shedding in animals inoculated at birth persisted through 164 days of age. These results indicate that the duration of WWA virus infection in N. albigula is dependent upon the animal's age at the onset of infection and that neonatal infection can result in chronic (perhaps lifelong) virus shedding.
Short report: Antibody responses of mice immunized with a tetravalent dengue recombinant protein subunit vaccine.
Authors: Simmons M , Murphy G S , Hayes C G
Published: May 2017

Recombinant proteins containing the B domain of dengue virus serotypes 1-4 fused to the maltose binding protein (MBP) of Escherichia coli were evaluated individually and as a tetravalent vaccine candidate in mice. Sera from mice immunized with monovalent DEN-MBP recombinant protein vaccines developed high titers of serotype homologous antibody in the enzyme-linked immunosorbent assay and the plaque-reduction neutralization test. Cross-reactive antibody titers were either several dilutions lower or not detectable. Sera from mice immunized with the tetravalent DEN subunit vaccine neutralized all 4 DEN viruses in the plaque-reduction neutralization test. The neutralizing antibody titers to each individual serotype were significantly greater than any cross-reactive neutralizing antibody titers induced by the monovalent vaccines, providing evidence that the tetravalent DEN recombinant subunit vaccine produced specific neutralizing antibody to all 4 serotypes of dengue virus.
Short report: Detection of borrelia (relapsing fever) in rural Ethiopia by means of the quantitative buffy coat technique.
Authors: Cobey F C , Goldbarg S H , Levine R A , Patton C L
Published: May 2017

The diagnosis of louse-borne relapsing fever is commonly made on the basis of the detection of Borrelia spirochetes on Giemsa-stained thin blood films. In the present study, we used acridine orange-coated quantitative buffy coat (QBC) tubes, centrifugation, and fluorescence microscopy to detect Borrelia. Between July and August 1998, we used the QBC technique to diagnose 7 patients with borreliosis who visited a rural clinic in southwest Ethiopia. In laboratory studies that used Borrelia burgdorferi as a model, we detected spirochetes at concentrations as low as 10 organisms/mm3, whereas the number of positive readings assessed by means of stained blood films fell significantly at dilutions below 3,263 organisms/mm3. The greater sensitivity of the QBC technique is important in areas where Borrelia is endemic, as in the Horn of Africa. It may also prove useful in evaluating relapsing fevers in travelers.
Rapid reappearance of Plasmodium falciparum after drug treatment among Senegalese adults exposed to moderate seasonal transmission.
Authors: Sokhna C S , Faye FBK  , Spiegel A , Dieng H , Trape J F
Published: May 2017

To investigate the relationship between the entomologic inoculation rate (EIR) and time to reappearance of malaria parasites after radical treatment under moderate seasonal transmission conditions, a study was undertaken in a mesoendemic area of Senegal where malaria transmission is concentrated over an annual three-month period and averages 12 infective bites per person per year. A three-day course of quinine was administered to 48 asymptomatic adults between 19 and 66 years of age. Malaria transmission and parasitemia were monitored every week for two months and cases of fever or symptoms were investigated as part of a daily clinical surveillance. The proportion of persons reinfected at Days 28, 35, and 56 was 25%, 38%, and 54%, respectively. Adults less than 40 years of age had a shorter time to reinfection. In this age group, the median Plasmodium falciparum reappearance time was 28 days, and it was estimated that only one infected mosquito bite was able to induce a patent infection among half of the subjects. Only 8% (2 of 26) of the reinfections caused a clinical attack. These data are discussed in the light of previous studies conducted among adults naturally exposed to intense perennial transmission or among naive volunteers receiving artificial challenges. Rapid reinfection occurs at very low EIRs and dramatic differences in actual and cumulated exposure to infected mosquito bites poorly affect the median time to reappearance of malaria parasites in endemic populations.
Geographic variation of notified Ross River virus infections in Queensland, Australia, 1985-1996.
Authors: Tong S , Bi P , Hayes J , Donald K , Mackenzie J
Published: May 2017

The spatial and temporal variations of Ross River virus infections reported in Queensland, Australia, between 1985 and 1996 were studied by using the Geographic Information System. The notified cases of Ross River virus infection came from 489 localities between 1985 and 1988, 805 between 1989 and 1992, and 1,157 between 1993 and 1996 (chi2(df = 2) = 680.9; P < 0.001). There was a marked increase in the number of localities where the cases were reported by 65 percent for the period of 1989-1992 and 137 percent for 1993-1996, compared with that for 1985-1988. The geographic distribution of the notified Ross River virus cases has expanded in Queensland over recent years. As Ross River virus disease has impacted considerably on tourism and industry, as well as on residents of affected areas, more research is required to explore the causes of the geographic expansion of the notified Ross River virus infections.
Haiti: absence of dengue hemorrhagic fever despite hyperendemic dengue virus transmission.
Authors: Halstead S B , Streit T G , Lafontant J G , Putvatana R , Russell K , Sun W , Kanesa-Thasan N , Hayes C G , Watts D M
Published: May 2017

In 1994-1996, 185 strains of dengue (DEN) virus types 1, 2, and 4 were recovered from febrile United States and other United Nations military personnel in Haiti. We wondered whether risk factors for dengue hemorrhagic fever (DHF) existed and, if so, were DHF cases occurring among Haitian children. Dengue transmission rates were studied in 210 school children (6-13 years old) resident in Carrefour Borough, Port-au-Prince, Haiti. When sera were tested for plaque-reduction neutralizing antibodies to DEN 1-4 viruses, nearly 85% had antibodies to two or more DEN serotypes. The annual transmission rate was estimated at 30%, a rate observed in countries endemic for DHE Haitian DEN 2 isolates were genotype I, which are repeatedly associated with DHF cases in Southeast Asia and American regions. Despite positive virologic pre-conditions, DHF cases were not recorded by experienced Port-au-Prince pediatricians. These observations, which are reminiscent of those in Africa, provide further evidence of a dengue resistance gene in black populations.
Community-based ivermectin therapy for onchocerciasis: comparison of three methods of dose assessment.
Authors: Shu E N , Okonkwo P O
Published: May 2017

A new method of assessment based on mid-upper arm circumference (MUAC) is described for dosage adjustment for community-based ivermectin distribution. We studied 878 subjects eligible for ivermectin dosing in Awhum, Nigeria. In a previous preliminary study of 40 persons, MUAC (in cm) correlated with weight (kg) in the first 20 male (r = 0.97, r2 = 0.95, P < 0.0001) and the first 20 female subjects (r = 0.94, r2 = 0.88, P < 0.0001). We therefore studied the use of height, physical appearance, and MUAC for calculating the dose of ivermectin. The MUAC-based schedule underdosed only 4.1% of the population. The methods based on height underdosed 3.3% and 21.1%, and assignment based on physical appearance underdosed 10.2% of the population studied. This MUAC-based method (13-15 cm, 0.5 tablet; 16-20 cm, 1.0 tablet; 21-27 cm, 1.5 tablets; > or = 28 cm, 2.0 tablets) is more convenient and corresponds closely to dosing by weight. An adaptation of this method with reference to other prevalent tropical diseases and their respective drugs is therefore advocated.
Incidence of symptomatic and asymptomatic Plasmodium falciparum infection following curative therapy in adult residents of northern Ghana.
Authors: Owusu-Agyei S , Koram K A , Baird J K , Utz G C , Binka F N , Nkrumah F K , Fryauff D J , Hoffman S L
Published: May 2017

Adult residents of holoendemic malaria regions in Africa have a naturally acquired immunity (NAI) to malaria that renders them more resistant to new infections, limits parasitemia, and reduces the frequency and severity of illness. Given such attributes, it is not clear how one might evaluate drug or vaccine efficacy in adults without serious confounding. To determine symptomatic and asymptomatic malaria attack rates in adults of northern Ghana, 197 men and women underwent curative therapy for any pre-existing malaria infections at the start of the high transmission (wet) season. They were monitored for first parasitemia and first clinical episode of infection by Plasmodium falciparum over a 20-week period (May-October 1996). The cumulative incidence of primary infection by P. falciparum was 0.98 and incidence density of infection was calculated to be 7.0 cases/person-year. Symptoms were reported by 19.5% of the individuals at the time of first recurrent parasitemia. Incidence of infection, parasite density, and the frequency of symptoms were comparable in males and females. The results suggest that NAI did not provide these adults with significant defense against rapid re-infection and suggest that this population-infection design could serve to demonstrate the efficacy of a drug or vaccine in preventing parasitemia.
Plasmodium falciparum dihydrofolate reductase alleles and pyrimethamine use in pregnant Ghanaian women.
Authors: Mockenhaupt F P , Eggelte T A , BÃ¶hme T , Thompson W N , Bienzle U
Published: May 2017

Drug resistance in Plasmodium falciparum affects prevention of malaria in pregnancy. In a cross-sectional study of 530 pregnant Ghanaian women, P. falciparum dihydrofolate reductase (DHFR) gene mutations linked with pyrimethamine resistance were assessed and associations with pyrimethamine intake were analyzed. P. falciparum infected 69% of women without pyrimethamine use, 59% of those who had a history of pyrimethamine consumption but a negative urine test, and 53% of individuals with a positive urine test. Eighty-one percent, 43%, and 74% of the isolates contained the mutations Asn-108, Ile-51, and Arg-59, respectively. Thr-108 occurred in 8%. Pyrimethamine use was associated with increased frequencies of Asn-108 and Arg-59 but not of Ile-51 or Thr-108. In women with prophylaxis, wild-type parasites were absent and anemia tended to be more common with an increasing number of DHFR gene mutations. Pyrimethamine appears to be not adequately effective in this part of Ghana, most likely due to the predominance of resistant parasites. Selection for resistance following insufficient prophylaxis could possibly affect the efficacy of future intermittent sulfadoxine-pyrimethamine treatment.
Prevention of sporogony of Plasmodium vivax in Anopheles dirus mosquitoes by transmission-blocking antimalarials.
Authors: Coleman R E , Polsa N , Eikarat N , Kollars T M , Sattabongkot J
Published: May 2017

The sporontocidal activity of four dihydroacridine-diones (WR-233602, WR-243251, WR-250547, and WR-250548) and three fluoroquinolones (WR-279135, WR-279298, and WR-279288) was determined against naturally circulating isolates of Plasmodium vivax. Laboratory-reared Anopheles dirus mosquitoes were infected with P. vivax by feeding them on gametocytemic volunteers reporting to local malaria clinics in Kanchanaburi and Tak provinces, Thailand. Four days after the infectious feed, mosquitoes were re-fed on uninfected mice treated 90 minutes previously with a given drug at a dose of 100 mg base drug/kg mouse body weight. Sporontocidal activity was determined by assessing both oocyst and sporozoite development. None of the fluoroquinolones exhibited sporontocidal activity against P. vivax, whereas all 4 dihydroacridine-diones affected sporogonic development to some degree. WR-233602 affected oocyst development, but had no impact on sporozoite production, WR-250548 affected oocyst development and had a limited effect on sporozoite production, and WR-243251 and WR-250547 had a marked impact on all phases of sporogony. These data demonstrate that experimental dihydroacridine-diones are capable of interrupting the sporogonic development of P. vivax. These compounds may be useful in preventing malaria transmission.
Human IgG1 and IgG4: the main antibodies against Triatoma infestans (Hemiptera: Reduviidae) salivary gland proteins.
Authors: Nascimento R J , Santana J M , Lozzi S P , AraÃºjo C N , Teixeira A R
Published: May 2017

The Triatoma infestans salivary gland proteins (TSGP) can induce local and systemic hypersensitivity reactions in humans. IgG antibodies against TSGP were present in higher levels in sera of Chagas disease patients, and in individuals living in triatomine-infested areas than in controls living in triatomine-free areas. TSGP-specific IgG1 was found in sera of Chagas patients, and of individuals living in triatomine-infested rural areas, and uniquely specific IgG4 was present in sera of Chagas patients living in triatomine-infested areas, reactive against TSGP. Unique specificities were not detected in sera of individuals reacting against the ubiquitous mosquito Culex quinquifasciatus saliva proteins (CSGP). In conclusion, IgG1 reactive against TSGP is the main antibody present in individuals living in the triatomine-infested study areas. Also, IgG4 is found in the sera of insect-transmitted Chagas disease patients living in study areas.
Detection and significance of inapparent infection in Chagas disease in western Venezuela.
Authors: AÃ±ez N , Crisante G , Rojas A , Carrasco H , Parada H , Yepez Y , Borges R , Guevara P , Ramirez J L
Published: May 2017

Inapparent infections of Trypanosoma cruzi were detected in symptomless seropositive people living in close proximity, and under the same conditions of risk, to patients with acute Chagas disease. Similar infections were also detected in sera samples of people from 25 villages of western Venezuela where Chagas disease is endemic. Seropositivity in all the 1,251 studied samples was established by use of 3 serological methods (direct agglutination test, indirect immunofluorescence antibody test, and enzyme-linked immunosorbent assay). Each seropositive sample was tested for detection of anti-T. cruzi-specific immunoglobulin (Ig) M and IgG levels and specific T. cruzi infection by molecular methodology (polymerase chain reaction assay). The combined analysis of the serologic (IgM and IgG levels), molecular (specific T. cruzi DNA), and statistical findings demonstrated the existence of a different stage of T. cruzi infection in asymptomatic patients, which is suggested to be recognized as inapparent infection. Its definition, significance, and comparison with typical Chagas disease phases are presented, and its potential epidemiological importance is discussed.
Assessment of Leishmaniasis notification system in Santiago del Estero, Argentina, 1990-1993.
Authors: YadÃ³n Z E , Quigley M A , Davies C R , Rodrigues L C , Segura E L
Published: May 2017

Using a capture-recapture method, this study evaluates the completeness of the cutaneous leishmaniasis (CL) surveillance system in four districts of Santiago del Estero province, Argentina, for the period 1990-1993. Four reporting sources were evaluated: medical records kept by health facilities, interviews conducted during a case-control study, and the national and provincial levels of the leishmaniasis surveillance system (LSS). Using the capture-recapture method it was estimated that 210 cases (95% confidence interval [CI]: 202-218) of CL occurred in the four districts during the study period. Completeness of reporting to the leishmaniasis surveillance system at the national level was estimated to be 44.8% (95% CI: 43.2-46.4). The study results indicate that there is substantial underreporting within the LSS, although it did show the appropriate secular trends. The reasons for under-reporting and methods for addressing this problem are discussed.