bluuebunny/crossref_metadata_2025 huggingface dataset:
ASSESSMENT OF TRANSMISSION-BLOCKING ACTIVITY OF CANDIDATE Pvs25 VACCINE USING GAMETOCYTES FROM CHIMPANZEES
Authors: COLLINS WILLIAM E. , BARNWELL JOHN W. , SULLIVAN JOANN S. , NACE DOUGLAS , WILLIAMS TYRONE , BOUNNGASENG AMY , ROBERTS JACQUELIN , STROBERT ELIZABETH , MCCLURE HAROLD , SAUL ALLAN , LONG CAROLE A.
Published: September 2018

Macaca mulatta monkeys were immunized with the candidate transmission-blocking vaccine against Plasmodium vivax, Pvs25, combined with alum or Montanide ISA 720. Efficacy was measured by combining post-immunization sera with gametocytes obtained from infections induced in chimpanzees using membrane-feeding techniques. The results indicate that immunization of M. mulatta monkeys with Pvs25 and Montanide ISA 720 was more effective than with alum in efficacy and resulted in the maintenance of a lasting transmission-blocking immunity to P. vivax. This was evident two weeks after the second immunization, and more strongly demonstrable 62 and 152 days after the second immunization. This transmission-blocking activity was strongly reinforced by a third immunization given 181 days after the primary immunization, as measured three weeks later by indirect membrane feeding. The use of gametocytes of P. vivax derived from infections induced in chimpanzees can contribute to the selection of appropriate constructs, formulations, and immunization regimens for the development of effective transmission-blocking vaccines.
PREVALENCE OF HIV AND OTHER SEXUALLY TRANSMITTED INFECTIONS AMONG FEMALE COMMERCIAL SEX WORKERS IN ARGENTINA
Authors: PANDO MARÍA A. , BERINI CAROLINA , BIBINI MARIEL , FERNÁNDEZ MAURO , REINAGA ELENA , MAULEN SERGIO , MARONE RUBÉN , BIGLIONE MIRNA , MONTANO SILVIA M. , BAUTISTA CHRISTIAN T. , WEISSENBACHER MERCEDES , SANCHEZ JOSÉ L. , AVILA MARÍA M.
Published: September 2018

Sexually transmitted infections (STIs) have shown to enhance the transmission of human immunodeficiency virus (HIV) and to be more common among female commercial sex workers (FSWs). A cross-sectional study was conducted among 625 FSWs in six cities of Argentina in 2000–2002. The seroprevalence of HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), human T-cell lymphotropic virus type I/II, and syphilis was 3.2%, 14.4%, 4.3%, 1.6%, and 45.7%, respectively. Syphilis was associated with older age (≥ 30 years, adjusted odds ratio [AOR] = 2.6 to 4.9), ≥ 10 years in sex work (AOR = 2.2), use of illegal drugs (AOR = 2.1), and a prior history of an STI (AOR = 3.0). HBV and syphilis was the most common co-infection in 44 (7.5%) subjects. FSWs in Argentina are exposed to HIV and other STIs due to high-risk sexual and illegal drug use behavior. Renewed efforts are necessary to intervene effectively in this high-risk population.
HEPATITIS E VIRUS INFECTION AS A MARKER FOR CONTAMINATED COMMUNITY DRINKING WATER SOURCES IN TIBETAN VILLAGES
Authors: TOOLE MICHAEL J. , CLARIDGE FRANCES , ANDERSON DAVID A. , ZHUANG HUI , MORGAN CHRISTOPHER , OTTO BRAD , STEWART TONY
Published: September 2018

In April–May 2001, a study was conducted to determine the prevalence of antibodies against hepatitis E virus (HEV) among 426 persons 8–49 years of age randomly selected from two groups of rural villages in central Tibet. Group 1 villages were assessed in 1998 as having poor quality water sources; new water systems were then constructed prior to this study. Group 2 villages had higher quality water and were not designated as priority villages for new systems prior to the study. No participants tested positive for IgM; only IgG was detected in the analyzed samples. Overall, 31% of the participants had ever been infected with HEV (95% confidence interval [CI] = 26.7–35.7%). The rate was higher in men (36.6%) than women (26.3%) and highest in those 30–39 years of age (49.1%). The rate of past infection was higher in group 1; the risk ratio was 2.77 (95% CI = 1.98–3.88). This difference is most likely the result of the poor quality of the original water sources in these villages. In resource-poor countries, HEV may be a useful health indicator reflecting the degree of contamination in village water sources. This may be especially important in rural areas (such as Tibet) where maternal mortality ratios are high because HEV may be an important cause of deaths during pregnancy in disease-endemic areas.
PATHWAYS OF EXPANSION AND MULTIPLE INTRODUCTIONS ILLUSTRATED BY LARGE GENETIC DIFFERENTIATION AMONG WORLDWIDE POPULATIONS OF THE SOUTHERN HOUSE MOSQUITO
Authors: FONSECA DINA M. , SMITH JULIE L. , WILKERSON RICHARD C. , FLEISCHER ROBERT C.
Published: September 2018

The southern house mosquito Culex quinquefasciatus is a principal vector of human lymphatic filariasis, several encephalitides (including West Nile virus), avian malaria, and poxvirus, but its importance as a vector varies considerably among regions. This species has spread with humans and is ubiquitous in tropical urban and suburban environments. This was the first mosquito to reach Hawaii and we performed a worldwide genetic survey using micro-satellite loci to identify its source. Our analyses showed divergent Old World and New World genetic signatures in Cx. quinquefasciatus with further distinctions between east and west African, Asian, and Pacific populations that correlate with the epidemiology of human filariasis. We found that in Hawaii south Pacific mosquitoes have largely replaced the original New World introduction of Cx. quinquefasciatus, consistent with their reported expansion to higher elevations. We hypothesize worldwide pathways of expansion of this disease vector.
ENHANCEMENT OF SPLENIC GLUCOSE METABOLISM DURING ACUTE MALARIAL INFECTION: CORRELATION OF FINDINGS OF FDG-PET IMAGING WITH PATHOLOGICAL CHANGES IN A PRIMATE MODEL OF SEVERE HUMAN MALARIA
Authors: KAWAI SATORU , IKEDA EIJI , SUGIYAMA MUNEHIRO , MATSUMOTO JUN , HIGUCHI TETSUYA , ZHANG HONG , KHAN NASIM , TOMIYOSHI KATSUMI , INOUE TOMIO , YAMAGUCHI HARUYASU , KATAKURA KEN , ENDO KEIGO , MATSUDA HAJIME , SUZUKI MAMORU
Published: September 2018

In the current study, to elucidate the clinical features of severe malaria, we performed whole-body positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) of Plasmodium coatneyi–infected acute-phase Japanese macaques. The infected monkeys clearly exhibited increase in splenic FDG uptake indicating marked enhancement of glucose metabolism. The standardized uptake values (SUVs) of the spleen in the infected monkeys were significantly higher than those in the uninfected monkey. At autopsy, splenomegaly was clearly present in all infected monkeys, and histopathologic findings included hyperplasia of lymphoid follicles in white pulp, a large number of activated macrophage, and congestion of parasitized red blood cells (PRBCs) and malaria pigments in red pulp. We suggest that increase in splenic glucose uptake may thus be closely related to activation of splenic clearance system against blood-stage malarial parasites.
PARASITEMIA, ANEMIA, AND MALARIAL ANEMIA IN INFANTS AND YOUNG CHILDREN IN A RURAL HOLOENDEMIC PLASMODIUM FALCIPARUM TRANSMISSION AREA
Authors: ONG’ECHA JOHN MICHAEL , KELLER CHRISTOPHER C. , WERE TOM , OUMA COLLINS , OTIENO RICHARD O. , LANDIS-LEWIS ZACHARY , OCHIEL DANIEL , SLINGLUFF JAMIE L. , MOGERE STEPHEN , OGONJI GEORGE A. , ORAGO ALLOYS S. , VULULE JOHN M. , KAPLAN SANDRA S. , DAY RICHARD D. , PERKINS DOUGLAS J.
Published: September 2018

Malarial anemia (MA) is a multifactorial disease for which the complex etiological basis is only partially defined. The association of clinical, nutritional, demographic, and socioeconomic factors with parasitemia, anemia, and MA was determined for children presenting at a hospital in a holoendemic area of Plasmodium falciparum transmission in western Kenya. Parasitemia was not associated with malaria disease severity. In univariate logistic regression, fever was significantly associated with parasitemia, and wasting was associated with increased presentation of MA. Caretaker’s level of education and occupation were significantly correlated with parasitemia, anemia, and MA. Housing structure was also significantly associated with parasitemia and anemia. Bed net use was protective against parasitemia but not anemia or MA. Multivariate logistic regression models demonstrated that fever, mother’s occupation, and bed net use were associated with parasitemia. In the current study, none of the factors were associated with anemia or MA in the multivariate models.
A RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED, CLINICAL TRIAL OF THE IMPACT OF MALARIA PREVENTION ON THE EDUCATIONAL ATTAINMENT OF SCHOOL CHILDREN
Authors: FERNANDO DEEPIKA , DE SILVA DAMANI , CARTER RICHARD , MENDIS KAMINI N. , WICKREMASINGHE RAJITHA
Published: September 2018

A double-blind, placebo-controlled trial of nine months duration was carried out to investigate the impact of malaria and its prevention on the educational attainment of school children in a malaria-endemic area in southern Sri Lanka where both Plasmodium falciparum and P. vivax infections are prevalent. A total of 587 children attending grades 1–5 in four schools and resident in the area were randomly allocated to chloroquine (n = 295) and placebo (n = 292) arms. Language and mathematics scores of end-of-term school examinations for 1998 and 1999 and number of days absent and reasons for absenteeism during seven months pre-intervention and nine months of the intervention were recorded. The results indicate that there were no differences in language (95% confidence interval [CI] = 48.44–53.78 in chloroquine group and 50.43–55.81 in placebo group) and mathematics (95% CI = 49.24–54.38 in chloroquine group and 51.12–56.38 in placebo group) scores between the two groups prior to the intervention. During the intervention, the malaria incidence rate decreased by 55% (95% CI = 49–61%) and school absenteeism due to malaria was reduced by 62.5% (95% CI = 57–68%) in children who received chloroquine compared with the placebo group. Post-intervention, children who received chloroquine scored approximately 26% higher in both language (95% CI = 21–31%) and mathematics (95% CI = 23–33%) than children who received placebo. In a multivariate model, educational attainment was significantly associated with taking chloroquine prophylaxis and absenteeism due to malaria (P < 0.001 for both) but not due to health causes other than malaria or non-health causes. Language scores were associated with number of malaria attacks (P < 0.022). Educational attainment was significantly better among children whose compliance to chloroquine prophylaxis was higher (P < 0.001). The data suggest that malarial attacks have an adverse impact on the educational attainment of the school child and prevention of these attacks significantly improves educational attainment of children living in malaria-endemic areas.
EFFECTIVE TREATMENT OF UNCOMPLICATED PLASMODIUM FALCIPARUM MALARIA WITH AZITHROMYCIN-QUININE COMBINATIONS: A RANDOMIZED, DOSE-RANGING STUDY
Authors: MILLER R. SCOTT , WONGSRICHANALAI CHANSUDA , BUATHONG NILLAWAN , McDANIEL PHILIP , WALSH DOUGLAS S. , KNIRSCH CHARLES , OHRT COLIN
Published: September 2018

Azithromycin, the most potent antimalarial macrolide antibiotic, is synergistic with quinine against Plasmodium falciparum in vitro. We assessed combinations of azithromycin and quinine against uncomplicated P. falciparum malaria at the Armed Forces Research Institute of Medical Sciences–Kwai River Clinical Center along the Thailand-Myanmar border, an area with a high prevalence of multidrug-resistant P. falciparum. Four regimens were assessed in an open-label dose-ranging design involving 61 volunteers. All received oral quinine (Q; 30 mg/kg/day divided every 8 hours for 3 days) with oral azithromycin (Az; 500 mg twice a day for 3 days, 500 mg twice a day for 5 days, or 500 mg three times a day for 3 days). A comparator group received quinine and doxycycline (Dx; 100 mg twice a day for 7 days). Study observation was 28 days per protocol. Sixty volunteers completed the study. Seven days of QDx cured 100% of the volunteers. One failure occurred in the lowest QAz regimen (on day 28) and none occurred in either of the two higher Az regimens. Cinchonism occurred in nearly all subjects. Overall, the azithromycin regimens were well tolerated, and no volunteers discontinued therapy. Three- and five-day azithromycin-quinine combination therapy appears safe, well tolerated, and effective in curing drug-resistant P. falciparum malaria. Further evaluation, especially in pediatric and obstetric populations, is warranted.
DIAGNOSING INFECTION LEVELS OF FOUR HUMAN MALARIA PARASITE SPECIES BY A POLYMERASE CHAIN REACTION/LIGASE DETECTION REACTION FLUORESCENT MICROSPHERE-BASED ASSAY
Authors: McNAMARA DAVID T. , KASEHAGEN LAURIN J. , GRIMBERG BRIAN T. , COLE-TOBIAN JENNIFER , COLLINS WILLIAM E. , ZIMMERMAN PETER A.
Published: September 2018

Improving strategies for diagnosing infection by the four human Plasmodium species parasites is important as field-based epidemiologic and clinical studies focused on malaria become more ambitious. Expectations for malaria diagnostic assays include rapid processing with minimal expertise, very high specificity and sensitivity, and quantitative evaluation of parasitemia to be delivered at a very low cost. Toward fulfilling many of these expectations, we have developed a post–polymerase chain reaction (PCR)/ligase detection reaction–fluorescent microsphere assay (LDR-FMA). This assay, which uses Luminex® FlexMAP™ microspheres, provides simultaneous, semi-quantitative detection of infection by all four human malaria parasite species at a sensitivity and specificity equal to other PCR-based assays. In blinded studies using P. falciparum-infected blood from in vitro cultures, we identified infected and uninfected samples with 100% concordance. Additionally, in analyses of P. falciparum in vitro cultures and P. vivax-infected monkeys, comparisons between parasitemia and LDR-FMA signal intensity showed very strong positive correlations (r > 0.95). Application of this multiplex Plasmodium species LDR-FMA diagnostic assay will increase the speed, accuracy, and reliability of diagnosing human Plasmodium species infections in epidemiologic studies of complex malaria-endemic settings.
SEROTYPE-SPECIFIC DIFFERENCES IN CLINICAL MANIFESTATIONS OF DENGUE
Authors: BALMASEDA ANGEL , HAMMOND SAMANTHA N. , PÉREZ LEONEL , TELLEZ YOLANDA , SABORÍO SAIRA INDIRA , MERCADO JUAN CARLOS , CUADRA RICARDO , ROCHA JULIO , PÉREZ MARIA ANGELES , SILVA SHEYLA , ROCHA CRISANTA , HARRIS EVA
Published: September 2018

Dengue, the most prevalent arthropod-borne viral disease of humans, is caused by four serotypes of dengue virus (DENV 1–4). Although all four DENV serotypes cause a range of illness, defining precisely which clinical characteristics are associated with the distinct serotypes has been elusive. A cross-sectional study was conducted on 984 and 313 hospitalized children with confirmed DENV infections during two time periods, respectively, in the same hospitals in Nicaragua: a 3-year period (1999–2001) when DENV-2 accounted for 96% of the viruses identified, and the 2003 dengue season when DENV-1 predominated (87% of identified serotypes). When the two periods were compared, more shock (OR 1.91, 95% CI 1.35–2.71) and internal hemorrhage (OR 2.05, CI 1.16–3.78) were observed in the period when DENV-2 predominated, whereas increased vascular permeability was associated to a greater degree with the DENV-1 period (OR 2.36, CI 1.80–3.09). Compared with the DENV-2 period, the DENV-1 season was associated with more hospitalized primary dengue cases (OR 3.86, CI 2.72–5.48) and more primary DENV infections with severe manifestations (OR 2.93, CI 2.00–4.28). These findings provide new data to characterize the pathogenic potential of distinct DENV serotypes in human populations.
A CLINICAL TRIAL OF ETHIONAMIDE AND PROTHIONAMIDE FOR TREATMENT OF LEPROMATOUS LEPROSY
Authors: FAJARDO TRANQUILINO T. , GUINTO RICARDO S. , CELLONA ROLAND V. , ABALOS RODOLFO M. , DELA CRUZ EDUARDO C. , GELBER ROBERT H.
Published: September 2018

In 1982–1984 we conducted a six-month clinical trial in 50 previously untreated lepromatous leprosy patients randomly assigned to directly observed monotherapy with one of two thioamides, ethionamide or prothionamide, each given six times a week at doses of either 250 mg or 500 mg. The findings of this study have only recently been analyzed, and the potential for the use of these thioamides in leprosy patients placed in perspective. However, because of the small number of patients included in this study, the results must be interpreted with some caution. Clinical improvement was noted in 74% of the patients treated with ethionamide and in 83% of those treated with prothionamide. Therapy was well tolerated and drug-related hepatotoxicity did not require discontinuation of therapy. The 500-mg dose of both ethionamide and prothionamide resulted in loss in Mycobacterium leprae viability more rapidly than did the 250-mg dose, and prothionamide at both dose levels was superior to the equivalent dose of ethionamide. Overall killing of M. leprae in this study was found to be similar to that obtained previously with dapsone and clofazimine, but less than was obtained with rifampin, minocycline, clarithromycin, pefloxacin, and ofloxacin.
INVESTIGATION OF CUTICULAR HYDROCARBONS FOR DETERMINING THE AGE AND SURVIVORSHIP OF AUSTRALASIAN MOSQUITOES
Authors: HUGO LEON E. , KAY BRIAN H. , EAGLESHAM GEOFF K. , HOLLING NEIL , RYAN PETER A.
Published: September 2018

The cuticular hydrocarbon (CH) technique of age grading mosquitoes was evaluated for use on laboratory-reared Aedes aegypti (L.), Anopheles farauti (Laveran), and Ochlerotatus vigilax (Skuse). Gas chromatography/mass spectroscopy was used to determine the relative abundance of five alkanes in hexane extracts from the legs of individual mosquitoes. Age-related changes to relative hydrocarbon abundances were observed from An. farauti and Ae. aegypti, which are vectors of malaria and dengue, respectively. Female An. farauti were classified into two age categories (1–5 and ≥ 5 days old at 27°C) and Ae. aegypti into three age categories (1 to < 5, 5 to < 9 and ≥ 9 days old at 27°C) based on these changes. However, there was an absence of predicable age-related changes to hydrocarbon abundance in Oc. vigilax. Simulation modeling was used to construct sequential sampling guidelines for the application of this technique to estimate the survivorship of Ae. aegypti and An. farauti populations. These guidelines define the relationship between the survival rate, number of mosquitoes sampled, CH-based predictions of age, and the accuracy of survival rate estimates. They demonstrated, for example, that if 19% of a population of Ae. aegypti is estimated to be ≥ 9 days old by CH analysis, an estimate of the daily survival rate from the exponential model should be based on a sample of 200 mosquitoes for the survival rate estimate to be within 5% of the actual rate. However, if only 10% of the population is estimated to be ≥ 9 days old, 500 mosquitoes would need to be analyzed for the survival rate estimate to be of equivalent accuracy.
MICROSPORIDIOSIS IN VENEZUELA: PREVALENCE OF INTESTINAL MICROSPORIDIOSIS AND ITS CONTRIBUTION TO DIARRHEA IN A GROUP OF HUMAN IMMUNODEFICIENCY VIRUS–INFECTED PATIENTS FROM ZULIA STATE
Authors: CHACIN-BONILLA LEONOR , PANUNZIO AMELIA P. , MONSALVE-CASTILLO FRANCISCA M. , PARRA-CEPEDA IRENE E. , MARTINEZ RODRIGO
Published: September 2018

Microsporidia are recognized as a cause of morbidity among patients infected with the human immunodeficiency virus (HIV). Infection rates for intestinal microsporidiosis in HIV-infected patients from Venezuela are unknown. To determine the prevalence and pathogenic role of microsporidia in these patients in northwestern Venezuela, a case control study was conducted in 103 outpatients (mean ± SD age = 37.3 ± 5.6 years). Microsporidia were detected using unconcentrated formalin-fixed stools examined by Weber’s chromotrope-based staining method. For identification of coccidia, modified Ziehl-Neelsen carbolfuchsin staining of formalin-ether concentrates were used, and for other pathogenic parasites, iron hematoxylin–stained smears and formalin-ether concentrates were examined. Microsporidial infections were detected in 14 (13.6%) of 103 patients and 39 (37.9%) had other parasitic pathogens. No significant difference was noted in the occurrence of the infection in patients with diarrhea (13 of 74, 17.6%) and controls (1 of 29, 3.4%) (P = 0.118). Nevertheless, this result may be due to the small sample size (n = 14) of infected individuals. The proportions of other pathogens in patients with or without diarrhea were not significantly different (P = 0.828). Microsporidiosis is common among the HIV-infected population in northwestern Venezuela. However, its pathogenic role in these patients is uncertain and warrants further investigation.
EVALUATION OF AN IMPROVED APPROACH USING RESIDENCES OF SCHISTOSOMIASIS-POSITIVE SCHOOL CHILDREN TO IDENTIFY CARRIERS IN AN AREA OF LOW ENDEMICITY
Authors: MASSARA CRISTIANO LARA , PEIXOTO SÉRGIO VIANA , ENK MARTIN JOHANNES , DA SILVA BARROS HÉLITON , CARVALHO OMAR DOS SANTOS , SAKURAI EMILIA , SCHALL VIRGINIA
Published: September 2018

School children were used as indicators for the identification of schistosomiasis-positive family members in a area of low endemicity. This study was designed to improve current schistosomiasis control programs by applying this strategy to identify schistosomiasis-positive individuals in a more efficient way. The initial prevalence among school children was 8.6%. However, the prevalence among the family members of these school children increased to 15.5%. In contrast to these findings the prevalence in family members of schistosomiasis-negative school children was 3.8%. Although the applied methodology showed a relatively low sensitivity (50.0%), the high negative predictive value (87.7%) indicates that a few positive family members of school children with a negative stool result will be missed. This shows that this method of evaluation could be a strategy for a more efficient and cheaper identification of schistosomiasis-positive individuals in areas of low endemicity.
HEALTH WORKERS’ AGREEMENT IN CLINICAL DESCRIPTION OF FILARIAL LYMPHEDEMA
Authors: McPHERSON TESS , FAY MICHAEL P. , SINGH SHANTI , PENZER REBECCA , HAY ROD
Published: September 2018

Severity of lymphedema and presence of entry lesions are risk factors for acute bacterial dermatolym-phangioadenitis (ADLA) in those with filarial lymphedema. Recurrent ADLA causes acute morbidity and progression of lymphedema severity; however, there is little work assessing the ability of health workers to reliably stage disease severity and identify risk entry lesions. This knowledge is important in initiation of management and assessing interventions. We evaluated inter-rater reliability with two independent health workers rating both legs of 17 patients using a questionnaire and the Dreyer classification of lymphedema. The health workers could reliably stage lymphedema with high agreement (RMAC weighted kappa of 0.89) and identify nail, interdigital, and other skin lesions. However, there was less consistency in identifying the clinical nature of skin lesions. This indicates that the Dreyer classification can be a replicable way to stage lymphedema and a questionnaire can deliver high observer agreement on the presence of risk lesions.
OPERATIONAL EVALUATION OF THE USE OF PHOTOGRAPHS FOR GRADING ACTIVE TRACHOMA
Authors: SOLOMON ANTHONY W. , BOWMAN RICHARD J. C. , YORSTON DAVID , MASSAE PATRICK A. , SAFARI SALESIA , SAVAGE BRIAN , ALEXANDER NEAL D. E. , FOSTER ALLEN , MABEY DAVID C. W.
Published: September 2018

We evaluated the reliability of photographs to verify field diagnoses of active trachoma. We examined 956 residents of a trachoma-endemic village for signs of trachoma using the World Health Organization simplified grading system. Two photographs of the right eye of 948 persons were independently graded (masked to field assessment) by the field examiner and two other experienced graders. There was only moderate agreement between field assessment and the subsequent photographic evaluations by the three graders. When we counted ungradable photographs as disagreements, mean kappa scores for the signs trachomatous inflammation (follicular [TF]) and trachomatous inflammation (intense [TI]) were 0.44 and 0.51, respectively. There was also only fair-to-moderate agreement between the three assessments (by different examiners) of the photographs. Either the signs TF and TI themselves are not as reliable as previously believed, or photographs should be used for their diagnosis only when reliability testing demonstrates better agreement than found here.
HAEMOPHILUS INFLUENZAE TYPE B MENINGITIS AMONG CHILDREN IN HANOI, VIETNAM: EPIDEMIOLOGIC PATTERNS AND ESTIMATES OF H. INFLUENZAE TYPE B DISEASE BURDEN
Authors: ANH DANG D. , KILGORE PAUL E. , KENNEDY WILLIAM A. , NYAMBAT BATMUNKH , LONG HOANG T. , JODAR LUIS , CLEMENS JOHN D. , WARD JOEL I. , _ _
Published: September 2018

From March 2000 to February 2002, a population-based study of Haemophilus influenzae type b (Hib) meningitis was conducted among children less than five years of age in Hanoi, Vietnam. Children with suspected bacterial meningitis were referred to hospitals and each patient underwent standardized clinical examination and microbiologic testing. In Hanoi, 580 children were evaluated for bacterial meningitis and 23 (4%) had confirmed or probable Hib meningitis. The incidence of all Hib meningitis was 12/100,000 child-years less than five years of age and 26/100,000 child-years less than two years of age. Nationally, an estimated 1,005 children less than five years of age are hospitalized for Hib meningitis and 5,107 are hospitalized for Hib pneumonia. Among children with Hib meningitis, at least 100 will develop severe neurologic sequelae and 40 will die. These data suggest there is a substantial burden of Hib disease in Vietnam. National leaders will be provided with these data to facilitate development of national vaccination policies for children in Vietnam.
EXPERIMENTALLY INFECTED HUMAN BODY LICE (PEDICULUS HUMANUS HUMANUS) AS VECTORS OF RICKETTSIA RICKETTSII AND RICKETTSIA CONORII IN A RABBIT MODEL
Authors: HOUHAMDI LINDA , RAOULT DIDIER
Published: September 2018

The human body louse, the natural vector of Rickettsia prowazekii, is able to experimentally transmit the normally flea-borne rickettsia R. typhi, suggesting that the relationships between the body louse and rickettsiae are not specific. We used our experimental infection model to test the ability of body lice to transmit two prevalent tick-borne rickettsiae. Each of two rabbits was made bacteremic by injecting intravenously 2 × 106 plaque-forming units of either R. rickettsii or R. conorii. Four hundred body lice were infected by feeding on the bacteremic rabbit and were compared with 400 uninfected lice. Each louse group was fed once a day on a separate seronegative rabbit. The survival of infected lice was not different from that of uninfected controls. Lice remained infected for their lifespan, excreted R. rickettsii and R. conorii in their feces, but did not transmit the infection to their progeny. The nurse rabbit of uninfected lice remained asymptomatic and seronegative. Those rabbits used to feed infected lice developed bacteremia and seroconverted. Although the body louse is not a known vector of spotted fevers, it was able in our study to acquire, maintain, and transmit both R. rickettsii and R. conorii.
EXPERIMENTAL INFECTION OF HUMAN BODY LICE WITH ACINETOBACTER BAUMANNII
Authors: HOUHAMDI LINDA , RAOULT DIDIER
Published: September 2018

The human body louse is currently recognized as a vector of Rickettsia prowazekii, Borrelia recurrentis, and Bartonella quintana. Previous studies have reported the isolation of Acinetobacter baumannii from the body lice of homeless patients. To study how the body louse acquires A. baumannii, we infected a rabbit by infusing 2 × 106 colony-forming units of the louse strain of A. baumannii. Two hundred body lice were infected by feeding on the bacteremic rabbit and compared with 200 uninfected lice and two groups of 200 lice feeding on rabbits infected either with another strain of A. baumannii or A. lwoffii. Each louse group received maintenance feedings once a day on another seronegative rabbit. Body lice that fed on rabbits infused with each Acinetobacter species demonstrated a generalized infection. The body lice did not transmit their infection to the nurse rabbit by bite while feeding or to their progeny (eggs and larvae). The lice excreted living Acinetobacter species within their feces. Only the louse strain of A. baumannii was pathogenic for the body louse. An increased mortality rate was observed between the second and third days post-infection; however, they remained infected for their lifespan.
PUPAL HABITAT PRODUCTIVITY OF ANOPHELES GAMBIAE COMPLEX MOSQUITOES IN A RURAL VILLAGE IN WESTERN KENYA
Authors: MUTUKU FRANCIS M. , BAYOH M. NABIE , GIMNIG JOHN E. , VULULE JOHN M. , KAMAU LUNA , WALKER EDWARD D. , KABIRU EPHANTUS , HAWLEY WILLIAM A.
Published: September 2018

The productivity of larval habitats of the malaria vector Anopheles gambiae for pupae (the stage preceding adult metamorphosis) is poorly known, yet adult emergence from habitats is the primary determinant of vector density. To assess it, we used absolute sampling methods in four studies involving daily sampling for 25 days in 6 habitat types in a village in western Kenya. Anopheles gambiae s.s. comprised 82.5% of emergent adults and Anopheles arabiensis the remainder. Pupal production occurred from a subset of habitats, primarily soil burrow pits, and was discontinuous in time, even when larvae occupied all habitats continuously. Habitat stability was positively associated with pupal productivity. In a dry season, pupal productivity was distributed between burrow pits and pools in streambeds. Overall, these data support the notion that source reduction measures against recognizably productive habitats would be a useful component of an integrated management program for An. gambiae in villages.
A MODEST MODEL EXPLAINS THE DISTRIBUTION AND ABUNDANCE OF BORRELIA BURGDORFERI STRAINS
Authors: BRISSON DUSTIN , DYKHUIZEN DANIEL E.
Published: September 2018

The distribution and abundance of Borrelia burgdorferi, including human Lyme disease strains, is a function of its interactions with vertebrate species. We present a mathematical model describing important ecologic interactions affecting the distribution and abundance of B. burgdorferi strains, marked by the allele at the outer surface protein C locus, in Ixodes scapularis ticks, the principal vector. The frequency of each strain in ticks can be explained by the vertebrate species composition, the density of each vertebrate species, the number of ticks that feed on individuals of each species, and the rate at which those ticks acquire different strains. The model results are consistent with empirical data collected in a major Lyme disease focus in New England. An applicable extension of these results would be to predict the proportion of ticks carrying human infectious strains of B. burgdorferi from disease host densities and thus predict the local risk of contracting Lyme disease.
HUMAN CAMPYLOBACTER-ASSOCIATED ENTERITIS ON THE CARIBBEAN ISLAND OF BARBADOS
Authors: WORKMAN SUZANNE N. , SOBERS STEPHANIE J. , MATHISON GEORGE E. , LAVOIE MARC C.
Published: September 2018

A longitudinal study of the incidence of Campylobacter enteritis in Barbados was undertaken from January 2000 to August 2003. Diarrheal stools received by the central public health laboratory were cultured for Campylobacter. The number of reported Campylobacter cases exceeded those of Shigella but were less than those of Salmonella, and increased steadily with each year. Isolates from stools were mainly C. jejuni (63.6%) and C. coli (31.8%). The highest isolation rate was found in children 1–4 years of age (40.8%), followed by infants less than 1 year of age (16.9%) and those 5–9 years of age (11.3%). The number of reported cases was higher in March, from June to August, and in November and December. There was no correlation between incidence and either rainfall, temperature, or humidity. Further epidemiologic investigation of this disease is needed to evaluate risk factors for Campylobacter infection and determine routes of transmission in Barbados.
GENETIC DIFFERENTIATION BETWEEN THE BAMAKO AND SAVANNA CHROMOSOMAL FORMS OF ANOPHELES GAMBIAE AS INDICATED BY AMPLIFIED FRAGMENT LENGTH POLYMORPHISM ANALYSIS
Authors: SLOTMAN MICHEL A. , MENDEZ MONIQUE M. , TORRE ALESSANDRA DELLA , DOLO GUIMOGO , TOURÉ YEYA T. , CACCONE ADALGISA
Published: September 2018

The main vector of malaria in sub-Saharan Africa, Anopheles gambiae, is subdivided into five chromosomal forms. Three of them (i.e., BAMAKO, SAVANNA, and MOPTI) are found in sympatry in Mali, where MOPTI can be distinguished from the other two forms based on differences in the ribosomal DNA locus. However, no molecular markers are available to distinguish BAMAKO from SAVANNA. We examined the banding patterns of 139 amplified fragment length polymorphism primer combinations in an attempt to identify diagnostic differences between SAVANNA and BAMAKO. Despite screening > 10,000 bands, no diagnostic differences were found. However, additional AFLP analyses indicated that BAMAKO is genetically differentiated from SAVANNA, with a significant Φst value of 0.072. This could indicate that gene flow between these forms is restricted in at least some portion of the genome and the lack of identifiable fixed differences between the two forms is probably due to their recent origin.
DETERMINANTS OF VECTOR SPECIFICITY OF O’NYONG NYONG AND CHIKUNGUNYA VIRUSES IN ANOPHELES AND AEDES MOSQUITOES
Authors: VANLANDINGHAM DANA L. , TSETSARKIN KONSTANTIN , KLINGLER KIMBERLY A. , HONG CHAO , MCELROY KATE L. , LEHANE MICHAEL J. , HIGGS STEPHEN
Published: September 2018

The alphaviruses o’nyong nyong virus (ONNV) and chikungunya virus (CHIKV) provide a unique system to study the viral genes involved in vector specificity. ONNV infects both anopheline and culicine mosquitoes, whereas CHIKV infects only culicine mosquitoes. In this study, chimeric viruses were constructed that contained genes from both ONNV and CHIKV. These chimeras and previously described full-length infectious clones of ONNV and CHIKV were evaluated in Anopheles gambiae and Aedes aegypti mosquitoes. Virus derived from the infectious clones of ONNV and CHIKV retained the vector specificity of the parental viruses. All six of the chimeras were found to infect Ae. aegypti mosquitoes at high rates but only the chimera containing viral genes encoding all of the structural proteins of ONNV was able to infect An. gambiae mosquitoes. These data indicate that all of the viral structural proteins are necessary for ONNV to infect An. gambiae mosquitoes.
ASSOCIATION BETWEEN LAND COVER AND HABITAT PRODUCTIVITY OF MALARIA VECTORS IN WESTERN KENYAN HIGHLANDS
Authors: MUNGA STEPHEN , MINAKAWA NOBORU , ZHOU GUOFA , MUSHINZIMANA EMMANUEL , BARRACK OKEYO-OWUOR J. , GITHEKO ANDREW K. , YAN GUIYUN
Published: September 2018

We examined the effects of land cover type on survivorship and productivity of Anopheles gambiae in Kakamega in the western Kenyan highlands (elevation = 1,420–1,580 meters above sea level). Under natural conditions, An. gambiae sensu lato adults emerged only from farmland habitats, with an estimated productivity of 1.82 mosquitoes/meter2/week, but not from forest and swamp habitats. To determine the effects of intraspecific competition and land cover types, semi-natural larval habitats were created within three land cover types (farmland, forest, and natural swamp), and three different densities of An. gambiae sensu stricto larvae were introduced to the larval habitats. The mosquito pupation rate in farmland habitats was significantly greater than in swamp and forest habitats, and larval-to-pupal development times were significantly shorter. At higher densities, the larvae responded to increased intraspecific competition by extending their development time and emerging as smaller adults, but initial larval density showed no significant effects on pupation rate. Land cover type may affect larval survivorship and adult productivity through its effects on water temperature and nutrients in the aquatic habitats, as shown by the significantly higher water temperature in farmland habitats, enhanced pupation rates and shortened development times from the addition of food to habitats, and a significant negative correlation of the occurrence of An. gambiae larvae with canopy cover and emergent plants in natural habitats. These results suggest that deforestation and cultivation of natural swamps in the western Kenyan highland create conditions favorable for the survival of An. gambiae larvae, and consequently increase the risks of malaria transmission to the human population.
DENGUE KNOWLEDGE AND PRACTICES AND THEIR IMPACT ON AEDES AEGYPTI POPULATIONS IN KAMPHAENG PHET, THAILAND
Authors: KOENRAADT CONSTANTIANUS J. M. , TUITEN WIETEKE , SITHIPRASASNA RATANA , KIJCHALAO UDOM , JONES JAMES W. , SCOTT THOMAS W.
Published: September 2018

A knowledge, attitude, and practice (KAP) survey and an extensive entomologic survey were conducted in two sub-districts of Kamphaeng Phet province, Thailand, to test the hypothesis that correct dengue knowledge and practice reduce dengue vector populations. We found a negative association between respondents’ knowledge of preventive measures and the number of unprotected containers in and around their houses. Knowledge of development sites was positively associated with unprotected containers. No relationships existed between knowledge of dengue and adult mosquito reduction practices. A higher number of unprotected containers increased the likelihood of the house being infested with one or more adult Aedes aegypti. Surprisingly, houses of respondents that used mosquito coils or had screening on doors and windows were significantly more likely to be infested (odds ratio =2.0) with adult Ae. aegypti. We conclude that there is a direct link between knowledge on dengue prevention and container protection practices, whereas measures against adult mosquitoes are used only when people experience a mosquito nuisance problem.
ESTABLISHMENT OF A HUMAN HEPATOCYTE LINE THAT SUPPORTS IN VITRO DEVELOPMENT OF THE EXO-ERYTHROCYTIC STAGES OF THE MALARIA PARASITES PLASMODIUM FALCIPARUM AND P. VIVAX
Authors: SATTABONGKOT JETSUMON , YIMAMNUAYCHOKE NONGNUCH , LEELAUDOMLIPI SURASAK , RASAMEESORAJ MANEERAT , JENWITHISUK RACHANEEPORN , COLEMAN RUSSELL E. , UDOMSANGPETCH RACHANEE , CUI LIWANG , BREWER THOMAS G.
Published: September 2018

Our understanding of the biology of malaria parasite liver stages is limited because of the lack of efficient in vitro systems that support the exo-erythrocytic (EE) development of the parasite. We report the development of a new hepatocyte line (HC-04) from normal human liver cells. The HC-04 cells have proliferated in hormone-free medium for more than 200 passages. The cells were hyperdiploid, resembled liver parenchymal cells, and synthesized major liver-specific proteins and enzymes. Using Plasmodium falciparum and P. vivax sporozoites harvested from salivary glands of infected mosquitoes, we showed that HC-04 cells supported the complete EE development of these two most prevalent human malaria parasites. The EE parasites attained full maturation as shown by their infectivity to human erythrocytes. The infection rates of the liver cells were estimated to be 0.066% and 0.041% for P. falciparum and P. vivax, respectively. As the first human hepatocyte line known to support complete EE development of both P. falciparum and P. vivax, HC-04 will provide an experimental model that can be used for studying the biology of liver stage malaria parasites.
PIGMENTED MONOCYTES ARE NEGATIVE CORRELATES OF PROTECTION AGAINST SEVERE AND COMPLICATED MALARIA IN UGANDAN CHILDREN
Authors: MUJUZI GODFREY , MAGAMBO BETTY , OKECH BRENDA , EGWANG THOMAS G.
Published: September 2018

Pigmented leukocytes are reported to be associated with severe malaria (SM). Blood smears from a case-control study of SM conducted in Apac Hospital in Northern Uganda were examined for pigmented leukocytes to investigate their association with measures of disease and clinical immunity in children less than 5 years old. Pigmented leukocytes, predominated by monocytes, were significantly greater in number in SM by comparison with uncomplicated malaria (UM). SM children with no pigmented leukocytes had significantly elevated hemoglobin, packed cell volumes, and titers of IgG anti-SERA5 by comparison with SM children with pigmented leukocytes. These differences were not observed in UM. A Spearman rank correlation analysis showed, in addition, a negative but weak correlation between pigmented monocytes and titers of IgG anti-Plasmodium falciparum lysate and IgG anti-EBA-175 in both SM and UM children. Thus, numbers of pigmented monocytes might be negative correlates of clinical immunity in a region of holoendemic malaria.
MALARIA RAPID DIAGNOSTIC TESTS IN TROPICAL CLIMATES: THE NEED FOR A COOL CHAIN
Authors: JORGENSEN PERNILLE , CHANTHAP LON , REBUENO ANTERO , TSUYUOKA REIKO , BELL DAVID
Published: September 2018

Malaria control programs in endemic countries increasingly rely on early case detection and treatment at village level. The rapid diagnostic tests (RDTs) and accompanying drugs on which the success of these programs depends deteriorate to varying degrees at high temperatures. To assess the ability of health systems to maintain RDTs within manufacturers’ specifications, we monitored temperatures in the delivery chain from manufacturer through to the village health worker in Cambodia and the Philippines. In both countries, storage temperatures regularly exceeded those recommended for most RDTs intended for field use, whereas temperatures during transport greatly exceeded the lower and upper limits. These results emphasize the need for good logistical planning during the introduction of point-of-care tests in tropical countries and the importance of considering the stability of diagnostic tests during procurement.
IMPORTANT EXPERIMENTAL PARAMETERS FOR DETERMINING INFECTION RATES IN ARTHROPOD VECTORS USING POOL SCREENING APPROACHES
Authors: KATHOLI CHARLES R. , UNNASCH THOMAS R.
Published: September 2018

Measuring transmission of a vector-borne infection is essential to understanding infection dynamics. When infection prevalence in the vector population is low, transmission is often measured by pool screening (also referred to as group testing). Several investigators have developed statistical methods to recover infection prevalence estimates from pool screen data. These are based on models that contain certain assumptions, and a pool screening approach must be designed to take these into account if accurate estimates of infection prevalence are to be obtained. Here we describe these assumptions and discuss appropriate sampling protocols. The sources of error inherent in pool screening are described, and we show that, under most conditions in which one would want to use group testing, most of the error results from sampling and not the pooling process. Issues involved in developing a sampling protocol, including the total number of insects to be screened and optimal pool size, are explored. The meaning of confidence intervals associated with prevalence estimates and the appropriate interpretation of these intervals are discussed.
PHENOTYPIC PLASTICITY AND GEOGRAPHIC VARIATION IN THERMAL TOLERANCE AND WATER LOSS OF THE TSETSE GLOSSINA PALLIDIPES (DIPTERA: GLOSSINIDAE): IMPLICATIONS FOR DISTRIBUTION MODELLING
Authors: TERBLANCHE JOHN S. , JACO KLOK C. , KRAFSUR ELLIOT S. , CHOWN STEVEN L.
Published: September 2018

Using the tsetse, Glossina pallidipes, we show that physiologic plasticity (resulting from temperature acclimation) accounts for among-population variation in thermal tolerance and water loss rates. Critical thermal minimum (CTMin) was highly variable among populations, seasons, and acclimation treatments, and the full range of variation was 9.3°C (maximum value = 3.1 × minimum). Water loss rate showed similar variation (max = 3.7 × min). In contrast, critical thermal maxima (CTMax) varied least among populations, seasons, and acclimation treatments, and the full range of variation was only approximately 1°C. Most of the variation among the four field populations could be accounted for by phenotypic plasticity, which in the case of CTMin, develops within 5 days of temperature exposure and is lost rapidly on return to the original conditions. Limited variation in CTMax supports bioclimatic models that suggest tsetse are likely to show range contraction with warming from climate change.
EFFICACY OF PRAZIQUANTEL DURING THE INCUBATION AND INVASIVE PHASE OF SCHISTOSOMA HAEMATOBIUM SCHISTOSOMIASIS IN 18 TRAVELERS
Authors: GRANDIÈRE-PÉREZ LUCIA , ANSART SÉVERINE , PARIS LUC , FAUSSART ALEXANDRA , JAUREGUIBERRY STÉPHANE , GRIVOIS JEAN-PHILIPPE , KLEMENT ELISE , BRICAIRE FRANÇOIS , DANIS MARTIN , CAUMES ERIC
Published: September 2018

The efficacy of praziquantel started during the incubation period of schistosomiasis has not been studied. Eighteen tourists were infected by Schistosoma haematobium during summer 2003 after bathing once in the same cascade in Mali. We observed the efficacy of praziquantel given at different phases. They received praziquantel at the first consultation, from Days 10 to 15 after exposure in eight asymptomatic patients (Group 1), from Days 28 to 40 in 4 asymptomatic patients (Group 2), and from Days 20 to 39 in 6 patients with acute schistosomiasis (Group 3). All Group 1 patients developed acute schistosomiasis, compared with none of the Group 2 patients (P < 0.004). Among the 10 patients treated during the acute phase, clinical status deteriorated in four cases. Seventeen of the 18 patients developed chronic schistosomiasis. Early praziquantel treatment was thus less effective than later treatment in preventing acute schistosomiasis, while neither treatment effectively prevented chronic schistosomiasis.
COINCIDENT FILARIAL, INTESTINAL HELMINTH, AND MYCOBACTERIAL INFECTION: HELMINTHS FAIL TO INFLUENCE TUBERCULIN REACTIVITY, BUT BCG INFLUENCES HOOKWORM PREVALENCE
Authors: LIPNER ETTIE M. , GOPI P. G. , SUBRAMANI R. , KOLAPPAN C. , SADACHARAM K. , KUMARAN PAUL , PREVOTS D. REBECCA , NARAYANAN P. R. , NUTMAN THOMAS B. , KUMARASWAMI V.
Published: September 2018

The prevalence of helminth and tuberculosis infections is high in South India, whereas Bacille-Calmette-Guerin (BCG) vaccine efficacy is low. Our aim was to determine whether concurrent helminth infection alters the ability to mount a delayed-type hypersensitivity response to tuberculin. In a cross-sectional study in southern India, individuals 6–65 years of age were screened for intestinal helminths, circulating filarial antigenemia, tuberculin reactivity, active tuberculosis, and history of BCG vaccination; 54% were purified protein derivative (PPD) positive, 32% had intestinal helminth infection, 9% were circulating filarial antigen positive, and 0.5% had culture-confirmed active tuberculosis. Only age and BCG vaccination were significantly associated with PPD reactivity; however, BCG vaccination was associated with a lower prevalence of hookworm infection relative to those without prior BCG vaccination. Neither intestinal helminth infection nor filarial infection was associated with diminished frequencies of PPD positivity. Our findings suggest that preceding helminth infection does not influence significantly the delayed-type hypersensitivity response to tuberculin.