bluuebunny/crossref_metadata_2025 huggingface dataset:
Schistosoma japonicum in the pig: the host-parasite relationship as influenced by the intensity and duration of experimental infection.
Authors: Willingham A L , Hurst M , BÃ¸gh H O , Johansen M V , Lindberg R , Christensen N O , Nansen P
Published: May 2017

Parasitologic, clinicopathologic, and pathologic aspects of Schistosoma japonicum infections of varying durations and intensities were studied in growing pigs injected intramuscularly with a dose of either 0, 100, 500, or 2,000 cercariae and killed at 4, 11, 17, or 24 weeks postinfection (PI). The number of viable worm pairs decreased significantly in the high dose group after 11 weeks PI but not in the lower dose groups; however, a stable population of immature worms persisted throughout the study in all dose groups. Liver egg counts also tended to decrease in the high dose group after 11 weeks but not in the other groups. Fecal egg excretion began at six weeks PI, was highest at eight weeks PI with a pronounced peak occurring only in the high dose group, and then decreased to low levels by 14 weeks PI in all groups. Egg counts from the feces as well as the liver correlated strongly with worm pair numbers during the acute phase of infection. The only clinicopathologic abnormality observed was an increase in circulating eosinophils corresponding to cercarial dose in all infected pigs by week six with peak counts occurring between six and eight weeks PI. The pigs exhibited no clinical signs of disease aside from diarrhea at the onset of patency. However, lesions were present throughout the large intestine of all infected pigs from 11 weeks PI, gradually decreasing with time. Severe liver fibrosis occurred in the 500 and 2,000 dose groups mainly at 11 weeks PI and then decreased in severity. In the liver, but not in the intestine, the severity of lesions at all time points was proportional to the cercarial dose given. The results indicate that after several weeks of patency, pigs with high intensities of S. japonicum infection are able to effectively eliminate the majority of adult worms while maintaining a stable population of immature schistosomes.
Effect of size and geographic origin of Aedes aegypti on oral infection with dengue-2 virus.
Authors: Sumanochitrapon W , Strickman D , Sithiprasasna R , Kittayapong P , Innis B L
Published: May 2017

Differences in larval habitats cause variation in the size of Aedes aegypti (L.) adults. We suspected that such size variation was related to the ease with which the mosquitoes could be infected with dengue virus. Using a rearing procedure that produced three distinct size classes of mosquitoes, we determined the percentage of mosquitoes that developed disseminated dengue-2 infection following oral feeding with a suspension containing 3.3 x 10(7) plaque-forming units/ml. Mosquitoes were reared from eggs deposited by females captured in either of two villages in Chachoengsao Province or in Bangkok, Thailand. More of the larger mosquitoes (10.7%) were infected than the medium (5.6%) or small (5.7%) mosquitoes. Mosquitoes from Bangkok were less easily infected (5.0%) than mosquitoes from either of the two villages (8.5% and 10.7%). These results suggest that quantitative risk assessment of dengue transmission may be very difficult unless inoculation rate is measured directly. Also, control procedures that reduce density of larvae in individual containers may exacerbate dengue transmission by creating larger mosquitoes that are more easily infected.
Short report: Diapause, transovarial transmission, and filial infection rates in geographic strains of La Crosse virus-infected Aedes triseriatus.
Authors: Woodring J , Chandler L J , Oray C T , McGaw M M , Blair C D , Beaty B J
Published: May 2017

La Crosse (LAC) virus is transmitted horizontally to vertebrates and vertically to progeny by Aedes triseriatus mosquitoes, and in northern midwestern states, this virus overwinters in diapausing eggs of the vector. In Florida, the vector remains active throughout the year and does not diapause. To determine if there is an association between diapause and vertical transmission efficiency of LAC virus, transovarial transmission (TOT), and filial infection (FI) rates were determined for geographic strains of Ae. triseriatus. The TOT rates were not significantly different for Ae. triseriatus originating from Florida (78%) and those from Wisconsin (85%). The FI rates did differ significantly between the two groups (33% and 45%, respectively, for the Florida and Wisconsin mosquitoes). Furthermore, a line of mosquitoes was selected from a Wisconsin colony that had a reduced diapause phenotype (the AD- strain). While this strain displayed TOT rates that were the same as the other Wisconsin mosquitoes (85%), the FI rates were significantly lower (34%), indicating a reduction in TOT efficiency. The role of vertical transmission capacity in LAC virus endemicity remains to be determined.
A randomized controlled trial of artemether/benflumetol, a new antimalarial and pyrimethamine/sulfadoxine in the treatment of uncomplicated falciparum malaria in African children.
Authors: von Seidlein L , Bojang K , Jones P , Jaffar S , Pinder M , Obaro S , Doherty T , Haywood M , Snounou G , Gemperli B , Gathmann I , Royce C , McAdam K , Greenwood B
Published: May 2017

We report here the results of a randomized double blind trial comparing coartemether (CGP56697), a combination of artemether and benflumetol, with pyrimethamine/sulfadoxine (P/S). Two hundred eighty-seven children 1-5 years of age with uncomplicated falciparum malaria were enrolled at two centers in The Gambia between July 1996 and December 1996. Following treatment, children were visited at home every 24 hr until a blood film free of asexual parasites was obtained. Genotyping of parasites was used to distinguish recrudescence from new infections. Three days after the start of treatment, 133 (100%) of the CGP56697-treated children compared with 128 (93.4%) of children treated with P/S had cleared their parasites (P = 0.003). The day 15 cure rate was 93.3% for CGP56697 and 97.7% for P/S (P = 0.13). Within the third and fourth week after initiation of therapy, 20 children treated with CGP56697 and one of the P/S-treated children returned with second malaria episodes (P < 0.0001). Genotyping suggested that the majority (19 of 23 [82.6%]) of these second episodes were due to new infections, supporting the World Health Organization recommendation that longer follow-up is not relevant for the assessment of drug efficacy. At the two-week follow-up, 28.9% of the P/S treated children but none of the CGP56697-treated children carried gametocytes (P < 0.0001). This study showed that CGP56697 is safe in African children with acute uncomplicated falciparum malaria, clears parasites more rapidly than P/S, and results in fewer gametocyte carriers. More frequent new infections within the third and fourth week following treatment with CGP56697 than treatment with P/S are likely to be due to the short prophylactic effect of CGP56697.
Identification of a subpopulation of immune Nigerian adult volunteers by antibodies to the circumsporozoite protein of Plasmodium falciparum.
Authors: Nwagwu M , Anumudu C A , Sodeinde O , Ologunde C A , Obi T U , Wirtz R A , Gordon D M , Lyon J A
Published: May 2017

Collections of human sera from malaria-endemic areas would be valuable for identifying and characterizing antigens as malaria vaccine candidates if the contributing serum donors' ability to resist infection were fully characterized. We prepared such a serum collection from 26 apparently immune Nigerian adults who failed to develop patent parasitemia for at least 20 weeks following a documented increase in antibodies to the circumsporozoite protein (CSP) from Plasmodium falciparum. Volunteers were evaluated five times per week for malaria symptoms and bimonthly for parasites by examining thick blood smears. The incidence rate over 13 months for the cohort was 42% (47 malaria-confirmed volunteers) and the risk of infection was 1.3 infections/year. Responses to CSP did not correlate with protection. Because antibody responses to antigens other than CSP may be associated with protection, the sera from these immune individuals may be useful for identifying and characterizing other potential malaria vaccine candidates.
Surveillance for Ross River virus infection using blood donors.
Authors: Aaskov J G , Chen J Y , Hanh N T , Dennington P M
Published: May 2017

The number of clinical Ross River virus (RRV) infections (epidemic polyarthritis) each year in Australia continues to grow despite extensive vector control programs. There is a need, therefore, for a surveillance program that can give sufficient warning of outbreaks of the disease so that highly focused preventative measures may be undertaken. The ability of a surveillance program, based on voluntary Red Cross blood donations, to predict outbreaks of epidemic polyarthritis was evaluated. Anti-RRV IgM antibody was detected in significant numbers of blood donors from throughout the state of Queensland 6-9 weeks prior to an increase in the number of notified cases of epidemic polyarthritis. At a local level, significant numbers of anti-RRV IgM blood donors were detected in Brisbane in 1996 four weeks prior to an increase in the number of notified cases of epidemic polyarthritis. This system of surveillance is technically simple, rapid (results are obtained in 2-3 days), it samples the human population from throughout the state, and it gives timely warning of outbreaks of epidemic polyarthritis.
Influence of humans and domestic animals on the household prevalence of Trypanosoma cruzi in Triatoma infestans populations in northwest Argentina.
Authors: Gurtler R E , Cohen J E , Cecere M C , Lauricella M A , Chuit R , Segura E L
Published: May 2017

In three rural villages of northwest Argentina, the overall proportion of domiciliary Triatoma infestans infected with Trypanosoma cruzi was 49% among 1,316 bugs individually examined for infection in March and October 1992). Most of the variation among individual households in the proportion of infected triatomines was explained by variations among houses in the proportion of bugs that fed on dogs or cats, the prevalence of infected dogs or cats, and the proportion of bugs that fed on humans, according to a logistic multiple regression analysis. The effects of human infection rates on bug infection rates were not statistically significant. After adjusting for the effects of other predictors, the presence of chickens in bedroom areas had negative and significant effects on the proportion of infected Triatoma infestans, and positive and significant effects on the number of T. cruzi-infected triatomines collected per person-hr per house. Dog or cat infection rates and the proportion of bugs that fed on dogs or cats and on chickens explained 80% of the total variance of infected-bug numbers in a linear multiple regression model. This is the first study to use detailed field data to show that variations in triatomine infection rates depend on bug host feeding patterns and dog or cat infection rates, while the presence of chickens in bedroom areas exerts opposite effects on the proportion and number of infected triatomines. Domestic animals play a crucial role in the domiciliary transmission of T. cruzi.
Testing for anti-circumsporozoite and anti-blood-stage antibodies for epidemiologic assessment of Plasmodium falciparum infection in travelers.
Authors: Cobelens F G , Verhave J P , Leentvaar-Kuijpers A , Kager P A
Published: May 2017

The purpose of this investigation was to assess the role of serology for establishing incidences of Plasmodium falciparum malaria and of exposure to P. falciparum in epidemiologic studies of travelers using chemoprophylaxis. The design was a prospective cohort study involving 548 short-term Dutch travelers to areas endemic for P. falciparum malaria. Sera were collected before departure and, together with the medical history, 2-6 weeks after return. All sera were tested for anti-circumsporozoite (CS) antibodies by an R32tet32-ELISA; sera of subjects reporting febrile illness during travel or after return or with anti-CS responses were tested for anti-blood-stage antibodies by an indirect fluorescence antibody test (IFAT). Five subjects (0.9%) reported P. falciparum malaria confirmed by thick blood smear examination (documented cases) and six (1.0%) reported treatment for malaria without a documented diagnosis (presumptive cases). Conversions in the IFAT were detected in six subjects, including all five documented cases and one presumptive case. Anti-CS antibodies were detected in seven subjects (1.3%), including three documented cases and four of 442 subjects with no history of fever or malaria treatment (0.9%). Incidence rates per 1,000 person-months of travel (95% confidence interval) of infection with P. falciparum, whether or not suppressed by chemoprophylaxis, were 16.9 (8-31) for all destinations and 91.6 (33-200) for West Africa. In epidemiologic studies of P. falciparum malaria in travelers, testing for antibodies to blood stages can increase the sensitivity and specificity of case detection; testing for antibodies to sporozoites may be useful for the assessment of exposure to P. falciparum in travelers using chemoprophylaxis, but the sensitivity is limited.
Lytic antibodies in Trypanosoma cruzi-infected persons with low parasitemia.
Authors: Zulantay I , Venegas J , Apt W , Solari A , Sanchez G
Published: May 2017

An antibody-dependent, complement-mediated lysis test performed with three Chilean trypomastigote strains used as target cells revealed strain dependence in the detection of lytic antibodies in chronic chagasic sera. The highest percentage of lytic sera was observed when MF or V115 strains were used as target cells (90% and 71%, respectively) in the chronic chagasic group with negative xenodiagnosis results. No significant statistical association was observed between lytic activity in chronic chagasic sera and the presence or absence of cardiopathy (P > 0.01). Western blot analysis showed that lytic sera recognize different antigens depending on the strain used and nonlytic sera had a weaker capacity to detect them.
Occurrence and susceptibility to antibiotics of Shigella species in stools of hospitalized children with bloody diarrhea in Pakistan.
Authors: Khalil K , Khan S R , Mazhar K , Kaijser B , Lindblom G B
Published: May 2017

The aim of the present investigation was to study the frequency of Shigella spp. in patients with bloody diarrhea in Pakistan and the susceptibility of isolated Shigella to three antibiotics: ampicillin, cotrimoxazole and nalidixic acid. In addition, the frequency of Campylobacter and Salmonella was also determined. Stool samples (n = 152) were collected from 152 diarrheic children less than six years of age passing blood and mucus in their stools who were admitted to Paediatric Department of Mayo Hospital in Lahore, Pakistan from June to September 1990. The samples were cultivated on standard media for Shigella, Campylobacter, and Salmonella. Susceptibility of Shigella isolates was tested by disk diffusion method. The frequency of isolation was 19.1% for Shigella spp., 7.9% for Campylobacter, and 4.6% for Salmonella. Shigella flexneri (7.9%) was the most frequently isolated species, followed by S. dysenteriae (6.6%), S. boydii, (3.3%) and S. sonnei (1.3%). All Shigella isolates were susceptible to nalidixic acid (100%), while only a few were susceptible to cotrimoxazole (7.0%) and ampicillin (3.5%). In Pakistan, self-medication and purchases of drugs without a prescription are commonly practiced. Thus, there is a greater possibility of development of resistant strains due to over use of antibiotics.
Molecular evolution of dengue type 2 virus in Thailand.
Authors: Rico-Hesse R , Harrison L M , Nisalak A , Vaughn D W , Kalayanarooj S , Green S , Rothman A L , Ennis F A
Published: May 2017

Dengue is a mosquito-borne viral infection that in recent years has become a major international public health concern. Dengue hemorrhagic fever (DHF), first recognized in Southeast Asia in the 1950s, is today a leading cause of childhood death in many countries. The pathogenesis of this illness is poorly understood, mainly because there are no laboratory or animal models of disease. We have studied the genetic relationships of dengue viruses of serotype 2, one of four antigenically distinct dengue virus groups, to determine if viruses obtained from cases of less severe dengue fever (DF) have distinct evolutionary origins from those obtained from DHF cases. A very large number (73) of virus samples from patients with DF or DHF in two locations in Thailand (Bangkok and Kamphaeng Phet) were compared by sequence analysis of 240 nucleotides from the envelope/nonstructural protein 1 (E/NS1) gene junction of the viral genome. Phylogenetic trees generated with these data have been shown to reflect long-term evolutionary relationships among strains. The results suggest that 1) many different virus variants may circulate simultaneously in Thailand, thus reflecting the quasispecies nature of these RNA viruses, in spite of population immunity; 2) viruses belonging to two previously distinct genotypic groups have been isolated from both DF and DHF cases, supporting the view that they arose from a common progenitor and share the potential to cause severe disease; and 3) viruses associated with the potential to cause DHF segregate into what is now one, large genotypic group and they have evolved independently in Southeast Asia for some time.
Association of Venezuelan equine encephalitis virus subtype IE with two equine epizootics in Mexico.
Authors: Oberste M S , Fraire M , Navarro R , Zepeda C , Zarate M L , Ludwig G V , Kondig J F , Weaver S C , Smith J F , Rico-Hesse R
Published: May 2017

Two outbreaks of encephalitis consistent with an etiology of Venezuelan equine encephalitis (VEE) virus occurred in equines on the Pacific coast of southern Mexico in 1993 (Chiapas State) and in 1996 (Oaxaca State). In Chiapas, there were 125 cases, of which 63 were fatal and in Oaxaca, there were 32 cases and 12 fatalities. Virus was isolated from two horses from each outbreak, including three brain isolates and one from blood. Virus isolates (93-42124, ISET-Chi93, Oax131, and Oax142) were shown by indirect immunofluorescence, hemagglutination inhibition, monoclonal antibody ELISA, and nucleotide sequencing to be VEE virus, subtype IE, a type previously thought to be equine-avirulent. Genetic characterization and phylogenetic analysis indicated that the outbreak viruses were identical or nearly identical to one another and that they were closely related to equine-avirulent IE strains from Guatemala and the Gulf coast of Mexico. In a plaque-reduction neutralization test, sera collected from healthy horses in Chiapas and Oaxaca reacted significantly better with isolate 93-42124 than with Guatemala IE isolate 68U201, suggesting that subtle genetic changes may have resulted in alteration of neutralization domains. It is not clear whether these differences may also influence equine virulence. However, renewed VEE virus subtype IE activity in Mexico, and its apparent conversion to equine virulence, underscores the need for increased surveillance, additional laboratory and epidemiologic studies in VEE-endemic regions, and possibly new vaccines.
High incidence of asymptomatic malara infections in a birth cohort of children less than one year of age in Ghana, detected by multicopy gene polymerase chain reaction.
Authors: Wagner G , Koram K , McGuinness D , Bennett S , Nkrumah F , Riley E
Published: May 2017

The incidence of Plasmodium falciparum infection has been followed in a birth cohort of 71 infants in southern Ghana, an area of perennial malaria transmission. Parasite DNA detection established the presence of a high rate of infection in newborns (13.6%), a low level of infection from two to 26 weeks (1.5-9.7%) and a steadily increasing parasite rate from 26 weeks of age. The median age to first infection was 42 weeks. Five cases of fever (temperature > or = 37.5 degrees C) and parasite density greater than 1,000 parasites/microl of blood, all in children more than 18 weeks of age, were considered possible cases of clinical malaria. The risk of infection was almost three times higher in the wet season than in the dry season and increased significantly from the age of 18 weeks. The level of malaria-specific IgG at birth was positively correlated with risk of infection in children 6-12 months of age, indicating that maternally derived anti-malarial IgG is correlated with exposure to malaria infection. There was no association between malaria-specific IgG at birth and risk of infection in children 0-6 months of age. However, infants do appear to possess mechanisms to limit parasite growth and a role for maternal antibody cannot be ruled out.
Treatment of chronic Chagas' disease with itraconazole and allopurinol.
Authors: Apt W , Aguilera X , Arribada A , PÃ©rez C , Miranda C , SÃ¡nchez G , Zulantay I , CortÃ©s P , Rodriguez J , Juri D
Published: May 2017

Four hundred four patients with chronic Chagas' disease were treated with itraconazole (6 mg/kg of body weight/day for 120 days), allopurinol (8.5 mg/kg of body weight/day for 60 days), or with a placebo of pure starch. Patients were monitored over a period of four years by clinical examination, serology, xenodiagnosis, hemoculture, and electrocardiogram. Drug tolerance was good, with only four treatments discontinued due to side effects that subsided after suspension of treatment. Parasitologic cure was evident in 44% of the those treated with allopurinol and 53% of those treated with itraconazole, and the electrocardiographic evaluation showed normalization in 36.5% and 48.2%, respectively, of patients with chronic or recent cardiopathy.
The role of serology in the diagnosis and prognosis of visceral leishmaniasis in patients coinfected with human immunodeficiency virus type-1.
Authors: Medrano F J , CaÃ±avate C , Leal M , Rey C , Lissen E , Alvar J
Published: May 2017

To define the possible role of serology in the diagnosis and prognosis of visceral leishmaniasis (VL) in patients with human immunodeficiency virus type-1 (HIV-1) infection, the dynamics of humoral immune responses was investigated in 20 coinfected patients. Sequential sera obtained before, during, and after VL diagnosis were analyzed by an indirect immunofluorescent antibody test (IFAT), a recombinant ELISA (using the rK39 protein), and immunoblotting. During the active course of the disease, positive results were found by IFAT or ELISA in 22% of the cases and by immunoblotting in 78% of the cases. A great variability in the response was observed during the follow-up with a trend to more positive results near the time of VL diagnosis. Forty-six percent of the patients were positive by IFAT or ELISA on at least one time point before VL and 37.5% were positive during the period following treatment. These results confirm the limited usefulness of the IFAT and ELISA in the diagnosis of VL in coinfected patients and demonstrate their low ability to predict the development or the outcome of disease. In these patients, immunoblotting could be a useful tool for studying the natural course of leishmaniasis, although it has limited value for diagnosis or treatment control.
A semisynthetic fetal calf serum-free liquid medium for in vitro cultivation of Leishmania promastigotes.
Authors: Ali S A , Iqbal J , Ahmad B , Masoom M
Published: May 2017

A semisynthetic, autoclavable, liquid medium that does not require inclusion of fetal calf serum (FCS) for the successful cultivation of Leishmania promastigotes in vitro is described. The parasites were grown in commercially available medium 199 supplemented with 10% FCS and 2% mammalian urine and the growth was compared with the same medium without FCS. The growth of the parasites in the semidefined medium without FCS was found to be as good as or slightly better that with medium 199 supplemented with FCS.
Indication of the presence of two distinct strains of Echinococcus granulosus in Iran by mitochondrial DNA markers.
Authors: Zhang L , Eslami A , Hosseini S H , McManus D P
Published: May 2017

Sixteen isolates of Echinococcus granulosus, collected from Iranian patients at surgery, and from domestic animals, including sheep, goats, cattle, and camels at slaughterhouses in Tehran and central and southern Iran were analyzed for DNA nucleotide and predicted amino acid sequence variation within regions of the mitochondrial cytochrome c oxidase I (COI) and NADH dehydrogenase subunit I (NDI) genes. A polymerase chain reaction-restriction fragment length polymorphism method, based on the DNA sequence variation in the NDI gene, was also used to rapidly survey the E. granulosus isolates. The isolates were categorized into two distinct and uniform genotype groupings. The analysis clearly indicated that the camel/dog strain (G6 genotype) of E. granulosus as well as the cosmopolitan, common sheep strain (G1 genotype) occur in Iran. The G1 genotype was found present in all four human isolates examined and it was more prevalent in domestic animals than the camel-restricted G6 genotype. In E. granulosus-endemic areas of Iran it is evident, therefore, that the majority of E. granulosus-infected livestock animals can potentially act as reservoirs of human infection, and this has important implications for hydatid control and public health.
Prevalence of Onchocerca volvulus nodules in the Sankuru River Valley, Democratic Republic of the Congo, and reliability of verbal assessment as a method for determining prevalence.
Authors: Law P A , Ngandu O N , Crompton P , Usungo O , Kosten D , Law J K , Burnham G
Published: May 2017

The epidemiology of onchocerciasis in much of the Democratic Republic of the Congo (formerly Zaire) is not well established. We report the results of an onchocerciasis rapid assessment survey carried out in 18 villages of the Sankuru River Valley in the central part of this country in preparation for mass distribution of ivermectin. Thirty men from each village were randomly selected and examined for subcutaneous nodules. The prevalence of nodules among these men in each village ranged from 82.5% to 100% with a mean prevalence of 95.0%. This study also assessed the validity of using verbal assessment instead of physical examination to determine prevalence of nodules. This verbal method had a sensitivity of 93.5% and a specificity of 83.3%. High sensitivity and specificity for this method suggest that it might be a cost-effective approach to determine the prevalence of onchocerciasis over large areas without using physical examinations requiring medical personal. This approach could be particularly useful where the coverage of health services is poor. The use of the Global Positioning System made it possible to send coordinates and survey data electronically to World Health Organization personnel in Geneva for computer generation of prevalence maps. The use of river boats to conduct surveys and support ivermectin distribution in the Congo is discussed.
An outbreak of cyclosporiasis in Florida in 1995: a harbinger of multistate outbreaks in 1996 and 1997.
Authors: Koumans E H , Katz D J , Malecki J M , Kumar S , Wahlquist S P , Arrowood M J , Hightower A W , Herwaldt B L
Published: May 2017

Before 1995, only one outbreak of cyclosporiasis had been reported in the United States. To identify risk factors for Cyclospora infection acquired in Florida in 1995, we conducted a matched case-control study (24 sporadic cases and 69 controls) and retrospective cohort studies of clusters of cases associated with two May social events (attack rates = 15.4% [8 of 52] and 54.5% [6 of 11]). In univariate analysis of data from the case-control study, consumption of fresh raspberries (odds ratio [OR] = 6.0, 95% confidence interval [CI] = 1.1-31.7) and bare-handed contact with soil (OR = 5.4, 95% CI = 1.4-20.7) were associated with infection; soil contact was also implicated in multivariate analysis. For the events, mixed-fruit items that had only fresh raspberries and strawberries in common had elevated relative risks (3.7 and 4.2), but the confidence intervals overlapped 1.0. The raspberries eaten at the events and by sporadic case-patients were imported. Given the cumulative evidence of the three studies and the occurrence in 1996 and 1997 of outbreaks in North America associated with consumption of Guatemalan raspberries, food-borne transmission of Cyclospora was likely in 1995 in Florida as well.
Domestic Aedes aegypti breeding site surveillance: limitations of remote sensing as a predictive surveillance tool.
Authors: Moloney J M , Skelly C , Weinstein P , Maguire M , Ritchie S
Published: May 2017

This project tested aerial photography as a surveillance tool in identifying residential premises at high risk of Aedes aegypti breeding by extending the use of a recently developed, ground-based, rapid assessment technique, the modified Premise Condition Index (PCI2). During 1995, we inspected 360 premises in Townsville, Australia for Ae. aegypti breeding, and PCI2 scores were recorded. The PCI2 values were also estimated from 1:3,000 color and infrared aerial photograph interpretation for the same premises. We found that shade levels can be accurately identified from both color and infrared images, and the PCI2 can be accurately identified from infrared photographs. Yard conditions, however, cannot be accurately identified from either aerial photograph type. The airborne PCI2 did not significantly correlate with breeding measures, and logistic regression further demonstrated that neither aerial photograph type allows the accurate prediction of Ae. aegypti breeding risk. Therefore, the ability of low-level aerial photography to enhance Ae. aegypti breeding site surveillance is at present limited, with ground surveillance remaining our most reliable tool for identifying the probability of Ae. aegypti breeding in the residential environment.
Detection of circulating antigens in patients with active Schistosoma haematobium infection.
Authors: Hassan M M , Medhat A , Makhlouf M M , Shata T , Nafeh M A , Osman O A , Deaf E A , Galal N , Fouad Y M
Published: May 2017

An antigen-capture ELISA using monoclonal antibody (MAb) 128C3/3/21 was used to detect circulating parasite-derived antigens in the sera of patients actively infected with Schistosoma haematobium (31 males and four females, 5-25 years of age). The assay had a sensitivity of 100% (35 of 35 patients with antigen levels > 80 ng/ml) and a specificity > 99%. We used this ELISA to monitor antigenemia before treatment and one, three, and six months after treatment with a single oral dose of praziquantel (PZQ) (60 mg/kg in 20 patients or 40 mg/kg in 15 patients) and compared our findings with those indicated by other measures of disease progression. Circulating antigen levels decreased drastically after PZQ treatment (P < 0.001), with a significantly higher decrease occurring after treatment with 60 mg/kg than with 40 mg/kg. Although the mean antigen level was still significantly reduced (P < 0.001) at six months after treatment, 16 patients remained antigen-positive after six months, and nine had increased levels of antigenemia, reflecting reinfection in six patients and persistence of infection in another. We observed a correlation (r = 0.6, P < 0.01) between the level of circulating antigen and the intensity of infection as measured by egg count. We also found a direct relationship (P < 0.001) between antigen level and the severity of the disease as monitored by ultrasonography. We conclude that our ELISA may be a useful adjunct to other methods, such as ultrasonography, for monitoring the course of S. haematobium infection and treatment.
Assessing the incidence of infection with Plasmodium falciparum among international travelers.
Authors: Jelinek T , BlÃ¼ml A , LÃ¶scher T , Nothdurft H D
Published: May 2017

Circumsporozoite (CS) antibodies, indicating plasmodial infection but not necessarily development of disease, have been shown to be reliable indicators of transmission in endemic areas. To estimate the actual rate of plasmodial infection, the prevalence of CS antibodies was investigated by an ELISA test system in a selected population of 2,131 travelers returning from areas endemic for malaria who presented to an outpatient clinic without any apparent symptom or clinical sign of malaria. Serum specimens from 104 of the investigated 2,131 patients (4.9%) were found to be positive (titer > or = 6.25 international ELISA units [IEU]). The geometric mean titer of antibody concentrations (IEU) in seropositive patients was 18.64 IEU (95% confidence interval [CI] = 13.15-24.13), while it was 2.1 IEU (95% CI = 1.8-2.4) in seronegative patients. A significantly above average risk for plasmodial infection could be found among travelers to East Africa (risk ratio [RR] = 4.5, P < 0.001), West Africa (RR = 4.5, P < 0.001), and Southern Africa (RR = 3.2, P = 0.015), while areas with a comparatively low risk included Central America (RR = 0.86, P < 0.001), the Indian subcontinent (RR = 0.45, P = 0.015), South America (RR = 0.49, P = 0.091), East Asia (RR = 0.68, P = 0.441), West Asia (RR = 0.24, P = 0.099), and Southeast Asia (RR = 0.69, P = 0.094). The results of this study emphasize the importance of adequate malaria chemoprophylaxis in nonimmune travelers to endemic areas. By use of the described method, estimates of the true infection rate of malaria in travelers can be derived for certain areas and the value of prophylactic measures can be demonstrated.
Identification of Brazilian flaviviruses by a simplified reverse transcription-polymerase chain reaction method using Flavivirus universal primers.
Authors: Figueiredo L T , Batista W C , Kashima S , Nassar E S
Published: May 2017

We report a simplified reverse transcription-polymerase chain reaction (RT-PCR) method for identification of Brazilian flaviviruses based on the patterns of electrophoretic separation of the amplicons. The RT-PCR was done on the culture fluids of Aedes albopictus C6/36 cells infected with Brazilian flaviviruses, without previous extraction of viral RNA, using Flavivirus universal primers that anneal to highly conserved sequences within the nonstructural protein 5 and 3'- non translated region of the virus genome. Genomes of 13 Brazilian Flavivirus isolates were amplified. It was not possible to amplify the genome of Bussuquara virus. Analysis of the RT-PCR products gave reproducible results and three distinct amplicon patterns were observed. CacipacorÃ© (800-850 basepairs [bp]) and yellow fever viruses (600 bp) yielded a single amplicon; dengue virus types 1 and 2 (650 and 550 bp), dengue virus type 4 (550 and 450 bp), Iguape (650-600 bp and 750-700 bp), St. Louis encephalitis (700 and 650-600 bp), and Rocio viruses (600 and 500-550 bp) yielded two amplicons; and Ilheus virus yielded five amplicons, two larger than 1,000 bp, one 650-700 bp, one 550-600 bp, and one 450-500 bp. The analysis of amplicon DNA sequences of six viruses showed homology with the 3'- nontranslated region of Flavivirus genome. The use of the Flavivirus universal primers in this simple RT-PCR technique is suitable as a screening test for the genus Flavivirus, with the exception of Bussuquara virus, in Brazilian isolates in tissue culture fluid.
Serodiagnosis and epidemiology of visceral leishmaniasis in Turkey.
Authors: Ozensoy S , Ozbel Y , Turgay N , Alkan M Z , Gul K , Gilman-Sachs A , Chang K P , Reed S G , Ozcel M A
Published: May 2017

Infantile Mediterranean visceral leishmaniasis (IVL) and anthroponotic cutaneous leishmaniasis (ACL) have long been known to exist in the western and southeastern Turkey, respectively. To further study these and other related diseases, a recombinant antigen (rK39) specific to VL was used in an ELISA for serodiagnosis of selected patients and for screening dog reservoir populations in several endemic sites. Among 24 confirmed VL cases from western Turkey, the rK39 ELISA proved to be more sensitive than a combination of cultivation and microscopy of bone marrow aspirates. The specificity of rK39 for leishmaniasis was demonstrated by its lack of cross-reactivity with sera from other human diseases in the same sites. Interestingly, six of the 83 parasitologically proven ACL cases from southeast Turkey were also rK39 positive. The end point titers of the positive VL and CL cases vary from 10(-2) to 10(-5) and from 10(-2) to 10(-3), respectively. The rK39 ELISA was also used to screen 494 apparently healthy dogs from Urfa in southeast Turkey, Manisa/Alasehir near the Aegean Sea, and Karabuk near the Black Sea. Eighteen rK39-positive cases (3.6%), all from the latter two areas, were found to have varying endpoint titers (10(-2)-10(-4)). The high titers predicted increased severity and frequency of the clinical symptoms (i.e., lymphadenopathy, depilation, skin lesion, weight loss and/or death), which were manifested subsequently in 16 of these 18 cases. In addition, more positive canine cases were diagnosed by the rK39 ELISA preclinically than the procedures to detect parasites postsymptomatically in the lymph node aspirates. The use of the rK39 ELISA as a sensitive tool makes it possible to demonstrate coendemicity of canine and human VL, as expected in the case of IVL. The results also point to the possible presence of additional VL types in western Turkey and cutanovisceral type in the southeast part of this country.
Serum IgM antibody response to the galactose-inhibitable adherence lectin of Entameoba histolytica.
Authors: Abd-Alla M D , Jackson T G , Ravdin J I
Published: May 2017

An ELISA for detection of serum IgM antibodies to the galactose-inhibitable adherence lectin of Entamoeba histolytica revealed that 2.8% of uninfected controls, 0.0% of controls infected with other parasites, 13.4% of asymptomatic amebic infections, 55% of colitis patients, and 77% of amebic liver abscess patients from Cairo, Egypt and Durban, South Africa had serum anti-lectin IgM antibodies. Of acute amebic colitis patients with symptoms for less than one week, only 6% possessed serum IgG anti-lectin antibodies, yet 45% had serum IgM antibodies to the amebic lectin. This compares with 65% of sera in acute colitis patients positive for lectin antigen as determined by ELISA with anti-lectin monoclonal antibodies. In conclusion, an ELISA for serum anti-lectin IgM antibodies appears to have greater clinical utility in the setting of acute amebic colitis than an ELISA for anti-lectin IgG antibodies, but is no more sensitive than an ELISA for detection of lectin antigen in sera.
GB virus C/hepatitis G virus infection among Colombian native Indians.
Authors: Tanaka Y , Mizokami M , Orito E , Ohba K , Nakano T , Kato T , Kondo Y , Ding X , Ueda R , Sonoda S , Tajima K , Miura T , Hayami M
Published: May 2017

To elucidate the prevalence of GB virus C/hepatitis G virus (GBV-C/HGV) infection in Colombian native Indians, serum GBV-C/HGV RNA was assayed in 163 native Indians and 67 members of the general population in Colombia. The native Indians (males:females = 40:123) and the members of the general population (males:females = 20:47) were tested by reverse transcription-semi-nested polymerase chain reaction. Of the 163 native Indians, 10 (6.1%) were positive for GBV-C/HGV RNA, compared with one (1.5%) of 67 from the general population. All Indians were negative for hepatitis B surface antigen and antibody to hepatitis C virus. Of 10 Indians with GBV-C/HGV RNA, the genotype of nine subjects was the Asian type. These data indicated that 1) the prevalence of GBV-C/HGV RNA in Colombian native Indians is high, and 2) GBV-C/HGV was probably brought from Asia and inherited for generations in some native Indian groups.
Plasmodium falciparum: purification of the various gametocyte developmental stages from in vitro-cultivated parasites.
Authors: Kariuki M M , Kiaira J K , Mulaa F K , Mwangi J K , Wasunna M K , Martin S K
Published: May 2017

Cultivated Plasmodium falciparum gametocytes reach maturity in vitro in approximately 14-16 days, during which they pass through five morphologically distinct developmental stages. Purification of the earlier developmental stages has not been previously reported. We have modified the standard discontinuous Percoll gradient method for the separation of stage IV and V gametocytes to obtain enriched preparations of those and the earlier P. falciparum gametocyte stages. In contrast to the stages II, III, and IV, the mature stage V gametocytes from our gradient readily transformed into gametes. Such preparations may be useful in research studies on the mechanisms that underlie gametocytogenesis.
Studies on control of visceral leishmaniasis: impact of dog control on canine and human visceral leishmaniasis in Jacobina, Bahia, Brazil.
Authors: Ashford D A , David J R , Freire M , David R , Sherlock I , EulÃ¡lio M C , Sampaio D P , Badaro R
Published: May 2017

To assess the effect of removing leishmania-infected dogs on the incidence of visceral leishmaniasis, a controlled intervention study was performed in northeast Brazil. The attempted elimination of seropositive dogs resulted in an initial significant decrease in the annual incidence of seroconversion among dogs from 36% to 6% over the first two years. In the following two years, the incidence increased to 11% and 14%, respectively. In a control area in which dogs were surveyed but seropositive dogs were not removed, the cumulative incidence did not vary significantly from year to year, ranging from 16% to 27%. In the intervention area, the prevalence of dog seropositivity decreased from 36% before the intervention to 10% and remained stable. These findings suggest that attempting to remove seropositive dogs is insufficient as a measure for eradicating visceral leishmaniasis in dogs. However, the force of transmission of infection among dogs can be reduced by such programs. Also, when the number of human cases before and after the start of the intervention was calculated, a significant decrease in incidence of disease in the intervention area was observed among children less than 15 years of age (P < 0.01). The results of this intervention study suggest that the elimination of the majority of seropositive dogs may affect the cumulative incidence of seroconversion in dogs temporarily and may also diminish the incidence of human cases of visceral leishmaniasis.
Severe malaria in Burkina Faso: influence of age and transmission level on clinical presentation.
Authors: Modiano D , Sirima B S , Sawadogo A , Sanou I , ParÃ© J , KonatÃ© A , Pagnoni F
Published: May 2017

We analyzed the clinical presentation of 800 severe malaria cases six months to 15 years of age (mean +/- SD = 4.3 +/- 3.0) recruited at the pediatric ward of the Ouagadougou University Hospital, and at the Sourou and Nayala District Hospitals in Burkina Faso. Inclusion criteria followed the World Health Organization (WHO) definition of severe and complicated malaria. The children were treated according to WHO guidelines with a complete regimen of drugs that were provided free of charge as part of the study. The case fatality rate of each sign and symptom of severe malaria was calculated on the 686 children whose outcomes were known. A total of 95 patients (13.8%) died while in the hospital; the mean +/- SD age of these children was 3.2 +/- 2.1 years. The age distribution and the clinical patterns of severe malaria was compared in patients from the urban areas of Ouagadougou characterized by relatively low transmission, and from rural areas where the mean inoculation rates are at least 20-fold higher. The mean +/- SD age of the urban and rural patients was 4.8 +/- 3.0 and 2.2 +/- 1.9 years, respectively (P < 0.001). The prevalence of coma was higher in the urban subsample (53.6% versus 28.9%; P < 0.001) while that of severe anemia (hemoglobin < 5 g/dL) was higher in rural patients (47.4% versus 14.8%; P < 0.001). Our data, in line with previous results obtained comparing rural areas characterized by different inoculation rates, show that the epidemiologic context influences the clinical presentation of severe malaria.
Human cystic echinococcosis in a Uruguayan community: a sonographic, serologic, and epidemiologic study.
Authors: Cohen H , Paolillo E , Bonifacino R , Botta B , Parada L , Cabrera P , Snowden K , Gasser R , Tessier R , Dibarboure L , Wen H , Allan J C , Soto de Alfaro H , Rogan M T , Craig P S
Published: May 2017

A prevalence and transmission study of human cystic echinococcosis (CE), due to infection with the dog tapeworm Echinococcus granulosus, was undertaken in the village of La Paloma in central Uruguay. The human population was registered and screened for CE by abdominal ultrasound scan as well as a number of serologic tests. Dogs were screened for E. granulosus infection by arecoline purgation as well as specific coproantigen testing. The total prevalence of human CE (new cases and those with a previous history) was 5.6% (64 of 1,149); 3.6% (40) of the cases were new ultrasound detected asymptomatic cases (mean age = 45 years). Age prevalence increased from 1.1% in the 4-6-year-old group to > 11% in the > 60-year-old group; the 20-29-year-old group had a significantly higher CE rate of 7.4%, compared with younger and older age groups, and there was no difference between sexes. A CE rate of 3.9% (20 of 514) was also recorded by ultrasound for new cases in the population residing outside the village. Most of the hydatid cysts were located in the liver presenting as either univesicular cysts or a solid mass, and of those 71% and 63%, respectively, with such cyst presentations were seropositive against E. granulosus cyst fluid antigens. Two of eight individuals who were filter paper blood spot seropositive, but ultrasound scan negative, were subsequently diagnosed respectively with pulmonary hydatidosis after radiography, and hepatic hydatidosis after computed tomography scan. Of 36 households with a CE patient, 32 were single cases while four households each harbored two CE cases. This did not represent a clustered distribution within families (23 of 117). Almost 20% of the dogs from La Paloma were found infected with E. granulosus after purge examination, with a mean worm number of 67 (range = 1-1,020). An additional eight dogs that were purge negative were Echinococcus coproantigen positive. The study showed that human CE is highly endemic in Uruguay, with one of the highest local prevalence rates in the world. Transmission appears to occur readily within well-developed towns, as well as on rural sheep ranches. Mass screening by ultrasound scanning with confirmatory serologic testing is an effective approach to case detection at the community level.
Ehrlichia chaffeensis in Missouri ticks.
Authors: Roland W E , Everett E D , Cyr T L , Hasan S Z , Dommaraju C B , McDonald G A
Published: May 2017

A nested polymerase chain reaction specific for Ehrlichia chaffeensis was used to attempt to amplify DNA from extracts of 100 individual ticks collected from 13 counties in central Missouri. Seventeen of 59 Amblyomma americanum and six of 41 Dermacentor variabilis ticks exhibited the characteristic 389-basepair product. This supports the hypothesis that these tick species may be vectors of human monocytic ehrlichiosis.
Species-specific repeat units in the intergenic spacer of the ribosomal RNA cistron of Anopheles aquasalis Curry.
Authors: Perera O P , Cockburn A F , Mitchell S E , Conn J , Seawright J A
Published: May 2017

A genomic DNA library of Anopheles aquasalis Curry was screened for clones that hybridized more intensely to DNA from A. aquasalis than to DNA from A. benarrochi Gabaldon, Cova Garcia, and Lopez, A. konderi Galvao and Damasceno, A. nuneztovari Gabaldon cytotypes A, B, and C, A. oswaldoi (Peryassu), A. rangeli Gabaldon, Cova Garcia, and Lopez, or A. trinkae Faran. Two specific clones (2.5 kilobasepairs [kbp] and 3.0 kbp) from A. aquasalis were isolated. Both A. aquasalis-specific clones were from the intergenic spacer region of the ribosomal RNA (rRNA) cistron. Upon digestion with Rsa I, a 900-bp fragment from the clone AA-1 hybridized specifically to A. aquasalis DNA. Analysis of the DNA sequence of this fragment revealed four tandemly repeated 36-bp units. Three of these repeat units were identical, and the fourth was 94% identical to the others. The DNA sequence of a highly conserved region of these repeats was used to synthesize an oligonucleotide probe specific to A. aquasalis.