bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of cardiac gated magnetic resonance imaging in murine Chagas' disease.
Authors: Jelicks L A , Shirani J , Wittner M , Chandra M , Weiss L M , Factor S M , Bekirov I , Braunstein V L , Chan J , Huang H , Tanowitz H B
Published: May 2017

To evaluate the role of gated cardiac magnetic imaging resonance (MRI) in Chagas' disease, we infected mice with Trypanosoma cruzi (Brazil strain). Two models were chosen for study, the CD1 and the inducible nitric oxide synthase knockout (NOS2-/-) mice. Infection of CD1 mice was associated with a significant increase in the right ventricular inner diameter (RVID) that was reversed in some mice by verapamil. Expression of cardiac NOS2 has been associated with myocardial dysfunction. Therefore, we evaluated chagasic cardiomyopathy in NOS2-/- and syngeneic wild type (WT) mice. Infected WT mice exhibited an increase in RVID in the acute phase (< 60 days postinfection) that was more marked during chronic infection (>100 days postinfection). Chronically infected NOS2-/- mice had an increase in RVID. The RVID in infected WT mice was greater than in NOS2-/- mice. These data demonstrate that MRI is a useful tool in the serial evaluation of the heart in murine Chagas' disease. In addition, it supports the notion that the NOS2-/-/NO pathway may contribute to the pathogenesis of murine chagasic cardiomyopathy.
Lack of an association between the ASN-108 mutation in the dihydrofolate reductase gene and in vivo resistance to sulfadoxine/pyrimethamine in Plasmodium falciparum.
Authors: RallÃ³n N I , Osorio L E , Giraldo L E
Published: May 2017

Sulfadoxine/pyrimethamine (SP) is considered an alternative treatment for acute uncomplicated malaria caused by Plasmodium falciparum resistant to chloroquine. However, the appearance of resistance to this drug has been reported since its initial use in Colombia. Molecular analysis of the dihydrofolate reductase gene indicates a correlation between in vitro resistance to SP and the Asn-108 point mutation. Little is known about the association of this point mutation and in vivo resistance to SP. We used a mutation-specific polymerase chain reaction strategy to analyze the presence of the Asn-108 point mutation in 48 clinical samples with adequate clinical response (ACR), 2 early treatment failures (ETF), and 1 late treatment failure (LTF). The Asn-108 mutation was detected in 36 of the ACR samples and in all of the ETF and LTF samples. Eleven ACR samples amplified with the wild-type-specific primer and one amplified with the primer for the Thr-108 mutation described for resistance to cycloguanil. These results suggest that the Asn-108 marker may not be useful in predicting SP treatment failure.
Polyclonal anti-tumor necrosis factor-alpha Fab used as an ancillary treatment for severe malaria.
Authors: Looareesuwan S , Sjostrom L , Krudsood S , Wilairatana P , Porter R S , Hills F , Warrell D A
Published: May 2017

Single doses (250, 500, 1,000, or 2,000 units/kg) of an ovine polyclonal-specific Fab fragment directed against tumor necrosis factor-alpha (TNF-alpha) were given to 17 adult patients with severe falciparum malaria immediately before treatment with artesunate in a pilot study to assess safety and optimal dosage with a view to future studies. Clinical and laboratory variables were compared with 11 controls. In the groups given Fab, there was a tendency for a faster resolution of clinical manifestations and reduction of fever but also a tendency towards longer parasite clearance times. Adverse events were more common in the control group and no early anaphylactic or late serum sickness reactions occurred in the Fab treated patients. On admission all patients had markedly elevated levels of TNF-alpha (85-1,532 ng/L) and interleukin-6 (IL-6) (30-27,500 ng/L). Also, 86% had elevated interferon-gamma (IFN-gamma) levels, 75% had increased IL-2 levels, 36% had increased IL-8 levels, and 21% had increased IL-1beta levels. Antibody treatment reduced IFN-gamma concentrations in a dose-related manner, but had no obvious effects on levels of other cytokines in this small study, although unbound TNF-alpha was undetectable after Fab treatment. Circulating concentrations of soluble E-selectin, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 were not affected by Fab treatment. The Fab exhibited a two-compartment, dose-proportional kinetics with an average elimination half-life of 12.0 hr, with about 20% being excreted renally. These results encourage a randomized, placebo-controlled trial in patients with cerebral malaria and provide some guidance about dosage.
Macrophage expression of class II major histocompatibility complex gene products in Paracoccidioides brasiliensis-infected mice.
Authors: Bocca A L , Silva M F , Silva C L , Cunha F Q , Figueiredo F
Published: May 2017

C57B1/6 isogenic mice infected with Paracoccidioides brasiliensis strains showed a disruption in the expression of Ia antigen. Expression slowly decreased during the course of the infection with a slight variation dependent on the route of inoculation and the fungal strain used, but production of interferon-gamma and tumor necrosis factor-alpha were observed. Suppression of Ia antigen expression and depression of the immunoproliferative responses of spleen cells were strongly correlated with nitric oxide levels. These parameters were inhibited when the animals were treated with nitro-L-arginine, which resulted in inhibition the activation of nitric oxide (NO) production. Analysis of the data showed that changes in the expression of the Ia antigen occur in P. brasiliensis infection and are strongly correlated with NO levels. These phenomena may be interrelated and reflect macrophage activation that contributes to the control of the disease and to the immunosuppression observed during the course of the infection.
Short report: evaluation of the potency and stability of a candidate vaccine against American cutaneous leishmaniasis.
Authors: Mayrink W , Pinto J , Da Costa C , Toledo V , GuimarÃ£es T , Genaro O , Vilela L
Published: May 2017

Availability of a safe, immunogenic, and affordable vaccine would represent the best strategy for control of cutaneous leishmaniasis (CL). Stability in field conditions is a essential property for any candidate vaccine. The stability and immunogenicity of three different preparations (thimerosal-preserved, autoclaved, and lyophilized) of a killed Leishmania amazonensis vaccine were assessed using fresh products and after 12 months of storage at 4 degrees C. Autoclaving was associated with a time-dependent decrease in the immunogenicity of the vaccine, as measured by the leishmanin skin test and production of interferon-gamma. These findings are of importance in the decision of which preparation of candidate killed CL vaccines should move to phase III trials.
Early, intermediate, and late acute stages in Chagas' disease: a study combining anti-galactose IgG, specific serodiagnosis, and polymerase chain reaction analysis.
Authors: Antas P R , Medrano-Mercado N , Torrico F , Ugarte-Fernandez R , GÃ³mez F , Correa Oliveira R , Chaves A C , Romanha A J , AraÃºjo-Jorge T C
Published: May 2017

The acute phase of Chagas' disease was classified as early, intermediate, and late based on the levels of anti-Galalpha, 3Gal IgG (Gal) and specific IgM (M) and IgG (G) anti-T. cruzi reactivity. While the early phase was M+G-Gal-, the intermediate phase was M+G-Gal+, M+G+Gal-, or M+G+Gal+, and the late phase was M-G+Gal+. This sequence of stages was consistent with our previous studies on acute-phase proteins. Analysis by the polymerase chain reaction (PCR) of parasite DNA in 65 blood samples of children living in Cochabamba, Bolivia showed a significant correlation (90.8%) between ELISA and PCR positivity. A lower correlation was observed between indirect hemagglutination, PCR (58%), and ELISA. Electrocardiographic analysis of 43 children studied by the PCR did not show any alteration typical of acute chagasic myocarditis. The PCR positivity was observed in eight samples where only Gal was increased, suggesting a very early T. cruzi infection, when specific antibodies were not yet present. By associating anti-Gal IgG with specific serology, early T. cruzi infection can be detected with greater precision. We suggest the use of anti-Gal antibody reactivity as an aid for the detection of recent T. cruzi infections, at least in endemic areas where diseases caused by other trypanosomatids do not overlap.
Resurgence of sleeping sickness in Tambura County, Sudan.
Authors: Moore A , Richer M , Enrile M , Losio E , Roberts J , Levy D
Published: May 2017

Endemic foci of human African trypanosomiasis are present in southern Sudan. In 1996 and 1997, trypanosomiasis increased sharply in Tambura County. To define the magnitude and geographic distribution of the outbreak, we conducted a prevalence survey using population-based cluster sampling in 16 villages: 1,358 participants answered questions about routine activities and tsetse fly contact and received serologic testing. Seroprevalence in the surveyed area was 19.4% (95% confidence interval = 16.9%, 21.8%). We confirmed infection in 66% of seropositive persons who received one parasitologic examination and in 95% of those who had serial examinations of lymph node fluid and blood. Activities related to the civil war, such as temporary migration, were not associated with seropositive status. Since the previous population screening in 1988, the trypanosomiasis prevalence increased two orders of magnitude, and the proportion of villages affected increased from 54% to 100%. Our results suggest that there may be 5,000 cases in Tambura County. The absence of trypanosomiasis control for nearly a decade is a factor in the resurgence of the disease.
Natural rodent host associations of Guanarito and pirital viruses (Family Arenaviridae) in central Venezuela.
Authors: Fulhorst C F , Bowen M D , Salas R A , Duno G , Utrera A , Ksiazek T G , De Manzione N M , De Miller E , Vasquez C , Peters C J , Tesh R B
Published: May 2017

The objective of this study was to elucidate the natural rodent host relationships of Guanarito and Pirital viruses (family Arenaviridae) in the plains of central Venezuela. Ninety-two arenavirus isolates from 607 animals, representing 10 different rodent species, were characterized to the level of serotype. The 92 isolates comprised 19 Guanarito virus strains and 73 Pirital virus strains. The 19 Guanarito virus isolates were from Zygodontomys brevicauda; 72 (98.6%) of the 73 Pirital virus isolates were from Sigmodon alstoni. These results indicate that the natural rodent associations of these 2 sympatric arenaviruses are highly specific and that Z brevicauda and S. alstoni are the principal rodent hosts of Guanarito and Pirital viruses, respectively.
Evidence for widespread infection of wild rats with hepatitis E virus in the United States.
Authors: Kabrane-Lazizi Y , Fine J B , Elm J , Glass G E , Higa H , Diwan A , Gibbs C J , Meng X J , Emerson S U , Purcell R H
Published: May 2017

Hepatitis E is an important medical pathogen in many developing countries but is rarely reported from the United States, although antibody to hepatitis E virus (anti-HEV) is found in > 1% of U.S. citizens. Zoonotic spread of the virus is suspected. Sera obtained from 239 wild rats trapped in widely separated regions of the United States were tested for anti-HEV. Seventy-seven percent of rats from Maryland, 90% from Hawaii, and 44% from Louisiana were seropositive for anti-HEV. Rats from urban as well as rural areas were seropositive and the prevalence of anti-HEV IgG increased in parallel with the estimated age of the rats, leading to speculation that they might be involved in the puzzling high prevalence of anti-HEV among some U.S. city dwellers. The discovery of a in rats in the United States and the recently reported discovery that HEV is endemic in U.S. swine raise many questions about transmission, reservoirs, and strains of HEV in developed countries.
Malaria parasitemia and childhood diarrhea in a peri-urban area of Guinea-Bissau.
Authors: Sodemann M , Jakobsen M S , MÃ¸lbak K , Alvarenga I C , Martins C , Aaby P
Published: May 2017

To examine the association between diarrhea in early childhood and malaria parasitemia, we conducted a nested case-control study in Guinea-Bissau of 297 children with diarrhea and a similar number of children without diarrhea matched for age, season, and residential area. There were no associations between diarrhea and parasite rate, parasite density, or clinical malaria. However, anti-malarials were easily available and frequently used, which was reflected by a 0.7% prevalence of children with a parasite density > 100/200 leukocytes. Thus, the findings do not preclude that diarrhea may be a sign of clinical malaria or high-parasite density in endemic areas with lower use of antimalarials.
Melioidosis with adrenal gland abscess.
Authors: Lee S C , Ling T S , Chen J C , Huang B Y , Sheih W B
Published: May 2017

We report a case of melioidosis with left adrenal gland abscess in a 51-year-old man from Taiwan who traveled to Rangoon, Burma for a four-day tour on July 15, 1997. The patient developed fever and left upper abdominal pain upon returning to Taiwan on July 19, 1997. Ten days after returning to Taiwan, he was admitted to Chang Gung Memorial Hospital in Keelung, Taiwan and blood culture on admission was positive for Burkholderia pseudomallei. Computerized tomography of the abdomen revealed left adrenal gland swelling and suppuration. Treatment with parenteral ceftazidime and cotrimoxazole for three weeks followed by two months of oral cotrimoxazole cured the infection. The patient remained asymptomatic at 12 months follow-up.
Evidence of rickettsial spotted fever and ehrlichial infections in a subtropical territory of Jujuy, Argentina.
Authors: Ripoll C M , Remondegui C E , Ordonez G , Arazamendi R , Fusaro H , Hyman M J , Paddock C D , Zaki S R , Olson J G , Santos-Buch C A
Published: May 2017

Between November 1993 and March 1994, a cluster 6 pediatric patients with acute febrile illnesses associated with rashes was identified in Jujuy Province, Argentina. Immunohistochemical staining of tissues confirmed spotted fever group rickettsial infection in a patient with fatal disease, and testing of serum of a patient convalescing from the illness by using an indirect immunofluorescence assay (IFA) demonstrated antibodies reactive with spotted fever group rickettsiae. A serosurvey was conducted among 16 households in proximity to the index case. Of 105 healthy subjects evaluated by IFA, 19 (18%) demonstrated antibodies reactive with rickettsiae or ehrlichiae: 4 had antibodies reactive with Rickettsia rickettsii, 15 with Ehrlichia chaffeensis, and 1 with R. typhi. Amblyomma cajennense, a known vector of R. rickettsii in South America, was collected from pets and horses in the area. These results are the first to document rickettsial spotted fever and ehrlichial infections in Argentina.
A novel Fab-based antivenom for the treatment of mass bee attacks.
Authors: Jones R G , Corteling R L , Bhogal G , Landon J
Published: May 2017

The frequency of mass bee attacks has dramatically increased in the Americas following the introduction and spread of the aggressive Africanized 'killer' bee (Apis mellifera scutellata). As yet no specific therapy is available, which led us to develop an ovine Fab-based antivenom as a potential new treatment. Sera from sheep immunized against the venom contained high levels of specific antibodies, as demonstrated by ELISA and by small-scale affinity chromatography, against both whole (A. m. mellifera) venom and purified melittin. A nerve muscle preparation was used to show the myotoxic effects of the venom and neutralization by the antivenom. Antivenom neutralizing ability was also demonstrated using assays for venom phospholipase A2 and in vivo activities. Venom from both European and Africanized bees appeared identical when analyzed by acid-urea gel electrophoresis. This antivenom may therefore provide the first specific therapy for the treatment of mass envenomation by either European or Africanized 'killer' bees.
Blood-stage dynamics and clinical implications of mixed Plasmodium vivax-Plasmodium falciparum infections.
Authors: Mason D P , McKenzie F E
Published: May 2017

We present a mathematical model of the blood-stage dynamics of mixed Plasmodium vivax-Plasmodium falciparum malaria infections in humans. The model reproduces features of such infections found in nature and suggests several phenomena that may merit clinical attention, including the potential recrudescence of a long-standing, low-level P. falciparum infection following a P. vivax infection or relapse and the capacity of an existing P. vivax infection to reduce the peak parasitemia of a P. falciparum superinfection. We simulate the administration of antimalarial drugs, and illustrate some potential complications in treating mixed-species malaria infections. Notably, our model indicates that when a mixed-species infection is misdiagnosed as a single-species P. vivax infection, treatment for P. vivax can lead to a surge in P. falciparum parasitemia.
Short report: a focus of Leishmania mexicana near Tucson, Arizona.
Authors: Kerr S F , McHugh C P , Merkelz R
Published: May 2017

Twenty-eight white-throated woodrats (Neotoma albigula) collected in Pima County, Arizona were screened for Leishmania using culture and the polymerase chain reaction (PCR). Two rodents were culture positive. Isoenzyme analysis determined the isolates to be Leishmania mexicana. The two culture-positive and four additional rodents were determined to be Leishmania-positive by the PCR. These isolates extend the geographic and ecologic range of enzootic leishmaniasis in the United States and represent a new host record.
Prevalence and risk of cysticercosis and taeniasis in an urban population of soldiers and their relatives.
Authors: GarcÃ­a-GarcÃ­a M L , Torres M , Correa D , Flisser A , Sosa-Lechuga A , Velasco O , Meza-Lucas A , Plancarte A , Avila G , Tapia R , Aguilar L , Mandujano A , AlcÃ¡ntara I , Morales Z , Salcedo A , MaÃ±on M D , Valdespino-Gomez J L
Published: May 2017

To determine markers of Taenia solium transmission and risk factors in an urban community, we studied 1,000 soldiers from a military camp in Mexico City and their relatives. Serum samples were used to detect antigens and antibodies and fecal specimens were examined for Taenia coproantigens and helminth eggs. Prevalences of 12.2% and 5.8% for cysticercosis were found among soldiers and their relatives, respectively. Taeniasis was found in 0.5% and none of the groups, respectively. Relatives of soldiers positive for cysticercosis and taeniasis markers ate more pork from street stores than restaurants or markets compared with relatives of soldiers without these indicators of infection. Also, 12.0% of the relatives of positive soldiers had a history of expelling tapeworm proglottids in the feces in contrast to 3.7% of the family members of the control group. Prevalence values and risk factors in this urban population are similar to those of previous studies performed in rural populations.
Endemic regions of paracoccidioidomycosis in Brazil: a clinical and epidemiologic study of 584 cases in the southeast region.
Authors: Blotta M H , Mamoni R L , Oliveira S J , NouÃ©r S A , Papaiordanou P M , Goveia A , Camargo Z P
Published: May 2017

This paper describes the clinical-seroepidemiologic characteristics of patients with paracoccidioidomycosis (PCM) who visited the University Hospital at the State University of Campinas (Campinas, Sao Paulo, Brazil). The study group consisted of 584 individuals (492 males and 92 females) with ages ranging from 5 to 87 years. The highest incidence of the disease occurred between the ages of 41 and 50 years for men and between 11 and 40 years for women. Rural activities were the principal occupation of 46% of the patients. The diagnosis was confirmed by histopathologic examination and demonstration of fungus in scrapings, secretions, or in the sputum. Serologic test results for PCM were positive in 80% of the 584 patients studied. The significant number of patients, including 33 children less than 14 years old, indicates the presence of the fungus in the area and that this region is an important endemic area for PCM.
Nutritional status of Helicobacter pylori-infected children in Guatemala as compared with uninfected peers.
Authors: QuiÃ±onez J M , Chew F , Torres O , BÃ©guÃ© R E
Published: May 2017

The effect of Helicobacter pylori infection on the nutritional status of children in a developing country was studied using a cross-sectional design. Children attending an all-girl public school in inner Guatemala City, Guatemala were evaluated to acquire sociodemographic information and anthropometric nutritional parameters (weight-for-height [WFH] and height-for-age [HFA]), and detect H. pylori-specific serum IgG antibodies. Of 211 children 5-10 years of age, 107 (51%) were infected. The WFH values were not different between infected and uninfected subjects, and were not affected by the sociodemographic variables. The HFA values decreased significantly with age (P = 0.008), lower income (P = 0.04), and H. pylori infection (P = 0.05). When controlled for age and income level, the effect of infection on HFA became nonsignificant (P = 0.30). Helicobacter pylori appeared to have no effect on the nutritional status of the studied children; the differences detected were small and likely due to sociodemographic factors.
Influence of sex on clinical features, laboratory findings, and complications of typhoid fever.
Authors: Khan M , Coovadia Y M , Connolly C , Sturm A W
Published: May 2017

Clinical features, laboratory findings, and complications of typhoid fever were correlated with sex through a retrospective case note review of 102 hospitalized culture-positive patients in Durban, South Africa. Intestinal perforation (P = 0.04), occult blood losses in stools (P = 0.04), and a mild reticulocytosis in the absence of hemolysis (P = 0.02) occurred more frequently in males than in females. A single pretreatment Widal O antibody titer > or = 1:640 was also a statistically significant occurrence in males (P = 0. 006). Female patients were significantly more severely ill (P = 0.0004) on admission and had chest signs consistent with bronchopneumonia (P = 0.04), transverse myelitis (P = 0.04), abnormal liver function test results (P = 0.0003), and abnormal findings in urinalyses (P = 0.02). Typhoid hepatitis (P = 0.04) and glomerulonephritis (P = 0.02) were present significantly more frequently in females. Whether these differences were due to differences in host's immune response to acute infection need to be determined in a prospective study.
Rhodesian trypanosomiasis in a splenectomized patient.
Authors: Malesker M A , Boken D , Ruma T A , Vuchetich P J , Murphy P J , Smith P W
Published: May 2017

We report the first apparent case of a splenectomized individual who developed severe trypanosomiasis with central nervous system involvement. The patient was a 41-year-old man who participated in an east African safari. Upon his return to the United States, the patient presented with an infection with Trypanosoma brucei rhodesiense that was treated successfully with suramin and melarsoprol. The onset of symptoms, laboratory studies, and disease progression did not differ from previously reported cases in the literature. The role of the spleen in trypanosomiasis is not well understood and the few reports available describe only animal models. This report suggests that asplenia had no apparent effect on the onset of symptoms and overall severity of illness. Further studies are necessary to ultimately define the role of the spleen in trypanosomiasis.
Synergism of benflumetol and artemether in Plasmodium falciparum.
Authors: Hassan Alin M , BjÃ¶rkman A , Wernsdorfer W H
Published: May 2017

Using a continuous in vitro culture system, the sensitivity of Plasmodium falciparum to artemether and a new antimalarial drug, benflumetol (lumefantrine), alone and in combination, was investigated with a multiresistant strain (T-996) from Thailand and a chloroquine-resistant strain (LS-21) from India. Both strains showed similar 50% inhibitory concentration (IC50) levels with artemether alone or benflumetol alone, but the IC90 was higher in strain T-996 compared with strain LS-21: for artemether, 34.45 and 7.11 nmol/L (10.28 and 2.12 ng/ml of erythrocyte-medium mixture [EMM]), and for benflumetol, 293.03 and 95.61 nmol/L (154.69 and 50.47 ng/ml of EMM). When tested in association at artemether:benflumetol (mol: mol) ratios between 100:1 and 1:100, substantial synergism was seen in both strains, especially at the IC90 and IC99 levels. This phenomenon resembles the synergistic interaction of artemisinin derivatives and mefloquine, first observed in laboratory models and later confirmed in clinical experience.
The role of corticosteroids in the treatment of cerebral schistosomiasis caused by Schistosoma mansoni: case report and discussion.
Authors: Fowler R , Lee C , Keystone J S
Published: May 2017

A 26-year-old Brazilian man was admitted to The Toronto Hospital with a headache and visual scintillation. His last travel to Brazil was five years previously. A computed tomography (CT) scan of the head showed an occipital mass with surrounding vasogenic edema. Occipital brain biopsy revealed Schistosoma mansoni eggs. The patient was treated with two doses of praziquantel (20 mg/kg) and dexamethasone (10 mg). His symptoms and occipital mass resolved. Cerebral schistosomiasis is, in part, caused by the host's inflammatory response to Schistosoma. Modes of treatment have included surgical resection, the antiparasitic drugs oxamniquine or praziquantel, and corticosteroids. Corticosteroids may diminish granulomatous inflammation, thereby preventing further tissue destruction, and there is evidence that they also reduce ova deposition. Our review of the literature supports prompt medical therapy in patients with cerebral schistosomiasis. While the minimally or asymptomatic individual may be treated with praziquantel alone, clinicians should consider adjunctive therapy with corticosteroids for patients with prominent neurologic signs or symptoms or mass lesions with evidence of surrounding edema on a CT scan or by magnetic resonance imaging.
Human Gongylonema infection in a resident of New York City.
Authors: Eberhard M L , Busillo C
Published: May 2017

A case of infection with Gongylonema is described in a 41-year-old woman living in New York City. The patient sought medical attention with the complaint of a sensation of 1-year duration of something moving in her mouth. On two occasions she removed worms from her mouth, once from her lip, once from the gum. One of the specimens submitted for examination was an adult female Gongylonema. It is not possible to say whether the infection was acquired in New York City, or elsewhere, since the patient traveled frequently to Mississippi to visit relatives. As cases of delusional parasitosis continue to increase, clinicians and laboratorians alike need to be alert to the possibility that foreign objects removed from the mouth, or elsewhere, may indeed represent unusual parasitic infections, and that these objects should be examined before being discarded.
Genetically distinct dog-derived and human-derived Sarcoptes scabiei in scabies-endemic communities in northern Australia.
Authors: Walton S F , Choy J L , Bonson A , Valle A , McBroom J , Taplin D , Arlian L , Mathews J D , Currie B , Kemp D J
Published: May 2017

Overcrowding is a significant factor contributing to endemic infection with Sarcoptes scabiei in human and animal populations. However, since scabies mites from different host species are indistinguishable morphologically, it is unclear whether people can be infected from scabies-infested animals. Molecular fingerprinting was done using three S. scabiei-specific single locus hypervariable microsatellite markers, with a combined total of 70 known alleles. Multilocus analysis of 712 scabies mites from human and dog hosts in Ohio, Panama and Aboriginal communities in northern Australia now shows that genotypes of dog-derived and human-derived scabies cluster by host species rather than by geographic location. Because of the apparent genetic separation between human scabies and dog scabies, control programs for human scabies in endemic areas do not require resources directed against zoonotic infection from dogs.
Seroprevalence of human cysticercosis in Maputo, Mozambique.
Authors: Vilhena M , Santos M , Torgal J
Published: May 2017

We carried out a serosurvey for cysticercosis among people visiting the Central Hospital of Maputo, the capital of Mozambique, between January and June 1993. A standardized questionnaire was designed to obtain information on demographic, socioeconomic, environmental, and behavioral characteristics related to the transmission of the infection. Four hundred eighty-nine individuals were tested for anti-cysticercosis antibodies: 222 blood donors and patients from the Department of Orthopedics, 148 patients from the Department of Neurology, and 119 patients from the Department of Psychiatry. The overall positivity rate was 12.1% (59 of 489). Anti-cysticercus antibodies was detected in 14.9% of the blood donors and patients from the Department of Orthopedics, 11.5% of the patients from the Department of Neurology, and 7.6% of the patients from the Department of Psychiatry. Living in poor sanitary conditions seems to be an important factor related to human cysticercosis in Maputo, Mozambique.
Houseflies: not simple mechanical vectors of enterohemorrhagic Escherichia coli O157:H7.
Authors: Kobayashi M , Sasaki T , Saito N , Tamura K , Suzuki K , Watanabe H , Agui N
Published: May 2017

An epidemic of enterohemorrhagic colitis caused by Escherichia coli O157:H7 (EHEC-O157) occurred in a nursery school in a rural area of Japan in September 1996. The EHEC-O157 were isolated both from patients and houseflies collected at the school. The flies were suspected to be mechanical vectors of the pathogen. Feeding experiments of EHEC-O157 to houseflies showed that the ingested bacteria were harbored in the intestine of flies and continued to be excreted at least for 3 days after feeding. Scanning electron microscopy showed that a large number of EHEC-O157 adhered to the surface of the housefly mouthparts and actively proliferated in the minute spaces of the labellum. Food masses containing EHEC-O157 in the fly intestine were completely surrounded by a peritrophic membrane during digestion and discharged rapidly. The persistence of bacteria in the intestine and feces is mainly a result of proliferation in the mouthparts and accumulation in the crop. Our results strongly suggest that houseflies are not simple mechanical vectors of EHEC. The epidemiologic potential of houseflies to disseminate EHEC-O157 may be greater than initially suspected.
Rapid identification of Burkholderia pseudomallei in blood cultures by latex agglutination using lipopolysaccharide-specific monoclonal antibody.
Authors: Dharakul T , Songsivilai S , Smithikarn S , Thepthai C , Leelaporn A
Published: May 2017

Melioidosis, an infection caused by Burkholderia pseudomallei, is endemic in Southeast Asia. The septicemic form of melioidosis is the leading cause of death due to community-acquired bacteremia in the northeastern part of Thailand. The delay in isolation and identification of the causative organism is a major contributing factor to the high mortality. The present study describes the evaluation of a latex agglutination test for rapid identification of the bacteria directly from blood cultures. The Bps-L1 monoclonal antibody recognized the lipopolysaccharide antigen of 96.8% of B. pseudomallei clinical isolates and was highly specific for B. pseudomallei. The diagnostic value of the latex agglutination test based on Bps-L1 monoclonal antibody was prospectively evaluated in an area endemic for melioidosis. The agglutination test kit was evaluated in 88 blood cultures with gram-negative bacteria identified with Gram staining. The sensitivity and specificity of the test kit were both 100%. These results indicated that the detection of B. pseudomallei lipopolysaccharide by specific monoclonal antibody in a latex agglutination format is clinically useful for the rapid identification of the bacteria in blood cultures in areas endemic for melioidosis.
Interethnic differences in the humoral response to non-repetitive regions of the Plasmodium falciparum circumsporozoite protein.
Authors: Modiano D , Chiucchiuini A , Petrarca V , Sirima B S , Luoni G , Roggero M A , Corradin G , Coluzzi M , Esposito F
Published: May 2017

We analyzed the humoral immune response to the amino- (amino acids 22-125) and carboxy-terminal (amino acids 289-390) non-repetitive domains of the Plasmodium falciparum circumsporozoite protein (PfCSP) in individuals belonging to three west African ethnic groups (the Fulani, Mossi, and RimaibÃ©) living in the same conditions of hyperendemic transmission in a Sudan savanna area of Burkina Faso. Previous surveys conducted in the same area showed obvious interethnic differences in the susceptibility and immune reactivity to malaria, with the Fulani showing lower infection and disease rates and higher humoral responses to various P. falciparum antigens than sympatric ethnic groups. A total of 764 subjects (311 Mossi, 273 RimaibÃ©, and 180 Fulani) of all age classes were tested. The total mean +/- SE anti-(CSPf-N-term) and anti-(CSPf-C-term) seroprevalences were 65.6 +/- 1.7% and 57.0 +/- 1.8%, respectively. These seroprevalences were lower than that recorded in the same sample for the central (NANP)40 repetitive domain (88.3 +/- 1.2%). As previously reported for other P. falciparum antigens (PfCSP-(NANP)40, thrombospondin-related anonymous protein, merozoite surface protein-1, Pf155-ring-infected erythrocyte surface antigen, and Pf332), in spite of similar exposure to malaria, the Fulani showed higher immune reactivity than sympatric populations for both antigens tested. Our results confirm the presence of B cell epitopes in the non-repetitive regions of the PfCSP; moreover a further evidence of interethnic differences in the capacity to mount humoral responses against P. falciparum malaria was obtained. The assessment of the biological basis of interethnic heterogeneities in the susceptibility and in the humoral immune responses to malaria appears relevant in the development of anti-malaria vaccines.
Dynamics of susceptibility and transmissibility of the live, attenuated, candidate vaccines dengue-1 PDK13, dengue-3 PGMK30F3, and dengue-4 PDK48 after oral infection in Aedes aegypti.
Authors: Jirakanjanakit N , Khin M M , Yoksan S , Bhamarapravati N
Published: May 2017

Dengue-1 virus PDK13 and isolates from vaccinees (dengue-1 Ib1 and dengue-1 Ib 10), dengue-3 PGMK30F3, and dengue-4 PDK48 were studied for their abilities to infect, disseminate, and replicate in Aedes aegypti mosquitoes by the oral route. In general, infection and dissemination rates were poorer for the vaccine compared with the parent viruses. The transmissibility was also lower for dengue-1 PDK13 than the parent virus, whereas it was not detected for isolates from vaccinees and dengue-3 PGMK30F3. Transmissibility of dengue-4 PDK48 was not determined because no dissemination occurred. Replication rates of vaccine strains were also found to be less efficient than the parent viruses. These imply that vaccination with the candidate vaccine is safe. Moreover, vector attenuation of vaccine viruses was consistent with its phenotypic markers of attenuation, which remained stable after a mosquito passage or after human and mosquito passage.
Complete nucleotide sequence of an Indian strain of Japanese encephalitis virus: sequence comparison with other strains and phylogenetic analysis.
Authors: Vrati S , Giri R K , Razdan A , Malik P
Published: May 2017

The RNA genome of an Indian strain of Japanese encephalitis virus (JEV), GP78, was reverse transcribed and the cDNA fragments were cloned in bacterial plasmids. Nucleotide sequencing of the cDNA clones covering the entire genome of the virus established that the GP78 genome was 10,976 nucleotides long. An open reading frame of 10,296 bases, capable of coding for a 3,432 amino acid polyprotein, was flanked by 95- and 585-base long 5'- and 3'-non-coding regions, respectively. When compared with the nucleotide sequence of the JaOArS982 strain, the JEV GP78 genome had a number of nucleotide substitutions that were scattered throughout the genome except for the 5'-noncoding region, the sequence of which was fully conserved. Comparison of the complete genome sequences of different JEV isolates showed a 1.3-4.1% nucleotide sequence divergence among them, which resulted in 0.6-1.8% amino acid sequence divergence. Analysis based on the complete genome sequences of different JEV isolates showed that the GP78 isolate from India was phylogenetically closer to the Chinese SA14 isolate.
Histologic and functional renal alterations caused by Bothrops moojeni snake venom in rats.
Authors: Boer-Lima P A , Gontijo J A , da Cruz-HÃ¶fling M A
Published: May 2017

Acute renal failure (ARF) is the main cause of death following snake bites by Bothrops species. In this study, we investigated the morphologic and functional renal disturbances caused by Bothrops moojeni venom in rats. Renal function was assessed based on creatinine and lithium clearances and on histologic examination of renal tissue 5 hr after the intravenous administration of 0.2 mg of venom/kg and 5 hr, 16 hr, and 48 hr after 0.4 mg of venom/ kg. A venom dose of 0.4 mg/kg produced renal tubule disturbances, including acute impairment of proximal and post-proximal tubule sodium handling associated with acute tubule necrosis. The glomerular filtration rate (GFR) decreased significantly and was accompanied by severe morphologic disturbances in the renal glomeruli. These functional and morphologic findings were observed in the absence of any change in mean arterial blood pressure. The decrease in GFR was not related to the presence of fibrin deposits in the glomerular capillary loops. These results suggest an early nephrotoxic action of B. moojeni venom involving significant morphologic and functional changes similar to those observed in snakebite-induced ARF in humans.
Replication of hepatitis B virus in first-degree relatives of patients with hepatocellular carcinoma.
Authors: Tai D I , Changchien C S , Hung C S , Chen C J
Published: May 2017

Hepatocellular carcinoma (HCC) may occur in family clusters. No genetic mechanism has been identified as responsible for this familial tendency. We suspected that a longer hepatitis B virus (HBV) replication phase might be the reason for a higher risk of HCC in families with this disease. We performed liver biochemical tests, test for viral hepatitis markers and hepatitis B e antigen (HBeAg), and liver ultrasonography in relatives of patients with HCC. A total of 1,885 first-degree relatives from 688 families participated in this study. Seven hundred fifty-two relatives were found to be carriers of hepatitis B surface antigen (HBsAg) and 675 of them were tested for HBeAg. The prevalence of HBeAg was 27.4% in relatives of those with HCC and 20% in asymptomatic HBsAg carriers. The HBeAg prevalence rate was higher in relatives of those with HCC > or = 40 years old than in asymptomatic HBsAg carriers. Moreover, HBeAg was more likely to persist in men than in women > or = 40 years old. We conclude that families with HCC showed a prolonged HBV replication phase that may be one of the cofactors for a familial tendency for HCC.
Seroepidemiologic survey of Orientia tsutsugamushi, Rickettsia typhi, and TT118 spotted fever group rickettsiae in rubber estate workers in Malaysia.
Authors: Tee T S , Kamalanathan M , Suan K A , Chun S S , Ming H T , Yasin R M , Devi S
Published: May 2017

The seroprevalence of Orientia tsutsugamushi, Rickettsia typhi, and TT118 spotted fever group (SFG) rickettsiae in 300 rubber estate workers in Slim River, Malaysia was determined in December 1996 and March 1997. In December, which was the wet season, 23.3%, 3.0%, and 57.3% of the population had antibodies detected against the three rickettsiae, respectively. The highest seropositive rate of 40% was detected for single infection with SFG rickettsiae, followed by a rate of 15.3% for both O. tsutsugamushi and SFG rickettsiae among the rubber estate workers. Subjects less than 21 years old had a lower seroprevalence of SFG rickettsiae compared with the other age groups. Indians had a higher seroprevalence of O. tsutsugamushi compared with other ethnic groups. Rubber tappers had a higher seroprevalence of SFG rickettsiae compared with other occupational groups. During the dry season in March 1997, there was a significant increase in the seroprevalence of R. typhi. The seroconversion rates for IgM against O. tsutsugamushi, R. typhi, and SFG rickettsiae were 5.7%, 12.3%, and 15.1%, respectively, during the four-month period. Significant variations of antibody titers towards the three rickettsiae was noted among subjects who were bled twice. This suggests a significant and continual exposure of rubber estate workers to the three rickettsiae.
Parasite-specific antibody profile in human fascioliasis: application for immunodiagnosis of infection.
Authors: Maher K , El Ridi R , Elhoda A N , El-Ghannam M , Shaheen H , Shaker Z , Hassanein H I
Published: May 2017

The antibody isotype response to an adult Fasciola worm antigen preparation (FWAP) was examined in sera from 60 Egyptians with parasitologically confirmed fascioliasis by an ELISA. The FWAP-specific IgG1 and IgG4 antibodies were found in 97-100% of the patients. The ratio of the mean absorbance values between infected patients and healthy controls was 9.7 and 29.7 for IgG1 and IgG4 antibodies, respectively. The IgM, IgA, IgG2, and IgG3 antibodies were less dominant. In contrast to IgG1 antibodies, which were often detected in sera from patients infected with Schistosoma, Echinococcus granulosus, Ascaris lumbricoides, Ancylostoma duodenale, or Hymenolepis nana, FWAP-specific IgG4 antibodies were detected exclusively in the sera of patients with fascioliasis. The data thus support the conclusion that an IgG4/ELISA with crude FWAP as antigen may be used for sensitive and accurate immunodiagnosis of human fascioliasis.
High frequency of serious side effects from meglumine antimoniate given without an upper limit dose for the treatment of visceral leishmaniasis in human immunodeficiency virus type-1-infected patients.
Authors: Delgado J , MacÃ­as J , Pineda J A , Corzo J E , GonzÃ¡lez-Moreno M P , de la Rosa R , SÃ¡nchez-Quijano A , Leal M , Lissen E
Published: May 2017

Organic pentavalent antimonials are one of the mainstays of treatment for visceral leishmaniasis (VL). Few data are available on the toxicity and efficacy of these drugs at the dosing schedule recommended by the Centers for Disease Control and Prevention (CDC) (Atlanta, GA). We analyzed 25 VL episodes in human immunodeficiency virus (HIV)-infected patients who were treated with meglumine antimoniate (MA) at the CDC-recommended dose in southern Spain. Adverse effects were observed in 14 (56%) VL episodes. In 7 (28%), treatment with MA was permanently discontinued due to serious adverse effects that included acute pancreatitis, acute renal failure, and leukopenia. Three (12%) patients died during therapy due to severe acute pancreatitis attributable to MA. The dosing regimen of MA currently recommended for treating VL is associated with a high rate of serious side effects in HIV-1-infected patients.
Molecular epidemiology of malaria in Yaounde, Cameroon V. analysis of the omega repetitive region of the plasmodium falciparum CG2 gene and chloroquine resistance.
Authors: Basco L K , Ringwald P
Published: May 2017

A novel Plasmodium falciparum gene, denoted cg2 gene, has been recently discovered, and a distinct genotype, characterized by 12 point mutations and 3 size polymorphisms, has been shown to be associated with chloroquine resistance in laboratory-adapted parasite strains. One of the polymorphic regions, denoted the omega region, consists of 16 tandem repeat units in chloroquine-resistant strains, while the chloroquine-sensitive strains have either < or = 15 or > or = 17 repeat units. In this study, the in vivo and in vitro responses were compared with the number of repeat units in the omega region of the cg2 gene for 75 Cameroonian isolates determined either by DNA sequencing or agarose gel electrophoresis. The 16-repeat units that characterize the resistant strains were found in 10 chloroquine-sensitive isolates (50% inhibitory concentration [IC50] < 100 nM) and 30 chloroquine-resistant isolates (IC50 > or = 100 nM). Thirty-five isolates (28 chloroquine-sensitive isolates and 7 chloroquine-resistant isolates) displayed < or = 15 or > or = 17 repeat units. Of the 18 patients responding with treatment failure, 15 were infected with parasites carrying 16 repeat units. Twenty-eight patients (11 with isolates carrying 16 repeat units and 17 with isolates carrying < or = 15 or > or = 17 repeat units) showed an adequate clinical response. The sensitivity, specificity, and predictive value were 81% (83%), 74% (61%), and 75% (58%), respectively compared with in vitro (or in vivo) responses. Neither the level of IC50 nor the key P. falciparum multidrug resistance gene 1 (pfmdr 1) allele at position 86 was associated with the number of omega repeat units. Although in vitro and in vivo resistance to chloroquine was statistically associated with the presence of 16 repeat units in the omega region (P < 0.05), the number of omega repeat units did not adequately discriminate patients infected with chloroquine-resistant parasites from those infected with chloroquine-sensitive parasites. Further studies on the cg2 gene are needed to determine whether cg2 gene is a reliable genetic marker for chloroquine resistance.
Incidence of plague associated with increased winter-spring precipitation in New Mexico.
Authors: Parmenter R R , Yadav E P , Parmenter C A , Ettestad P , Gage K L
Published: May 2017

Plague occurs episodically in many parts of the world, and some outbreaks appear to be related to increased abundance of rodents and other mammals that serve as hosts for vector fleas. Climate dynamics may influence the abundance of both fleas and mammals, thereby having an indirect effect on human plague incidence. An understanding of the relationship between climate and plague could be useful in predicting periods of increased risk of plague transmission. In this study, we used correlation analyses of 215 human cases of plague in relation to precipitation records from 1948 to 1996 in areas of New Mexico with history of human plague cases (38 cities, towns, and villages). We conducted analyses using 3 spatial scales: global (El NiÃ±o-Southern Oscillation Indices [SOI]); regional (pooled state-wide precipitation averages); and local (precipitation data from weather stations near plague case sites). We found that human plague cases in New Mexico occurred more frequently following winter-spring periods (October to May) with above-average precipitation (mean plague years = 113% of normal rain/ snowfall), resulting in 60% more cases of plague in humans following wet versus dry winter-spring periods. However, we obtained significant results at local level only; regional state-wide precipitation averages and SOI values exhibited no significant correlations to incidence of human plague cases. These results are consistent with our hypothesis of a trophic cascade in which increased winter-spring precipitation enhances small mammal food resource productivity (plants and insects), leading to an increase in the abundance of plague hosts. In addition, moister climate conditions may act to promote flea survival and reproduction, also enhancing plague transmission. Finally, the result that the number of human plague cases in New Mexico was positively associated with higher than normal winter-spring precipitation at a local scale can be used by physicians and public health personnel to identify and predict periods of increased risk of plague transmission to humans.