Evolution of coauthorship networks: worldwide scientific production on leishmaniasis

Introduction Collaboration is one of the defining features of contemporary scientific research, and it is particularly important with regard to neglected diseases that primarily affect developing countries. Methods The present study has identified publications on leishmaniasis in the Medline database from 1945 to 2010, analyzing them according to bibliometric indicators and statistics from social network analysis. Examining aspects such as scientific production, diachronic evolution, and collaboration and configuration of the research groups in the field, we have considered the different types of Leishmania studied and the institutional affiliation and nationality of the authors. Results Seven-hundred and thirty-five authors participate in 154 prominent research clusters or groups. Although the most predominant and consolidated collaborations are characterized by members from the same country studying the same type of Leishmania, there are also notable links between authors from different countries or who study different clinical strains of the disease. Brazil took the lead in this research, with numerous Brazilian researchers heading different clusters in the center of the collaboration network. Investigators from the USA, India, and European countries, such as France, Spain, the United Kingdom, and Italy, also stand out within the network. Conclusions Research should be fostered in countries such as Bangladesh, Nepal, Sudan, and Ethiopia, where there is a high prevalence of different forms of the disease but limited research development with reference authors integrated into the collaboration networks.

Twenty-eight years of Aedes albopictus in Brazil: a rationale to maintain active entomological and epidemiological surveillance

INTRODUCTION: Aedes albopictus was first detected in Brazil in 1986. This mosquito species presents a major threat to public health because Brazilian populations have shown substantial vector competence for arboviruses such as dengue and chikungunya. METHODS: We updated the records of Ae. albopictus in several States of Brazil, focusing on areas in which its presence had been reported after 2002. RESULTS: Twenty-eight years after its arrival in Brazil, Ae. albopictus has been detected in 24 of 27 States. CONCLUSIONS: The rapid spread of this species and its high vector competence demonstrate the danger of Ae. albopictus in Brazil.

Opportunistic infections among individuals with HIV-1/AIDS in the highly active antiretroviral therapy era at a Quaternary Level Care Teaching Hospital

INTRODUCTION : In this study, clinical-laboratory and epidemiological characteristics are described for a group of 700 individuals with HIV (human immunodeficiency virus)/AIDS (acquired immunodeficiency syndrome) in the ART (antiretroviral therapy) era at a teaching hospital that provides a quaternary level of care, with an emphasis on opportunistic infections (OIs), co-infections and immune profile. METHODS : A retrospective cross-sectional study of AIDS cases was conducted from 1998 to 2008 by reviewing medical records from the Base Hospital/FUNFARME (Fundação Faculdade Regional de Medicina), São José do Rio Preto, São Paulo, Brazil. RESULTS: The individuals were 14 to 75 years of age, and 458 were males. Heterosexuals accounted for 31.1% of all patients. Eighty-three percent were on ART, and 33.8% of those presented difficulties with treatment adherence. OIs were analyzed from medical records, and Pneumocystis jiroveci pneumonia was the most prevalent, regardless of the LTCD4+ (TCD4+ Lymphocytes) levels. Individuals whose viral loads were ≥10,000 showed a 90% greater chance of neurotoxoplasmosis. For P. jiroveci pneumonia, neurotoxoplasmosis, esophageal candidiasis, pulmonary tuberculosis and neurocryptococcosis, the chances of infection were higher among patients with LTCD4+ levels below 200 cells/mm3. HIV/hepatitis C virus (HCV) and HIV/hepatitis B virus (HBV) co-infections were significantly associated with death. CONCLUSIONS : OIs remain frequent in the ART era even in populations where the access to medical care is considered satisfactory.

New strategies for active finding of leprosy cases in the Amazonian region

AbstractINTRODUCTION: The use of the Self-Image Form (SIF) expands the identification of active leprosy cases to neighbors of index cases.METHODS: The SIF was used to screen two groups: case (neighbors of index cases of leprosy) and control (individuals residing next to houses without leprosy) group. A specialist investigated suspected leprosy cases for disease confirmation.RESULTS: New cases of leprosy were diagnosed in the case group (n = 7, 8.6%), but not the control group.CONCLUSIONS: The new surveillance strategy is inexpensive, efficient, and feasible within a primary health strategy. Future studies can help improve the use of the SIF.

A rapid method for testing in vivo the susceptibility of different strains of Trypanosoma cruzi to active chemotherapeutic agents

A method is described which permits to determine in vivo an in a short period of time (4-6 hours) the sensitivity of T. cruzo strains to known active chemotherapeutic agents. By using resistant- and sensitive T. cruzi stains a fairly good correlation was observed between the results obtained with this rapid method (which detects activity against the circulating blood forms) and those obtained with long-term schedules which involve drug adminstration for at least 20 consecutive days and a prolonged period of assessment. This method may be used to characterize susceptibility to active drugs used clinically, provide infomation on the specific action against circulating trypomastigotes and screen active compounds. Differences in the natural susceptibility of Trypanosoma cruzi strains to active drugs have been already reported using different criteria, mostly demanding long-term study of the animal (Hauschka, 1949; Bock, Gonnert & Haberkorn, 1969; Brener, Costa & Chiari, 1976; Andrade & Figueira, 1977; Schlemper, 1982). In this paper we report a method which detects in 4-6 hours the effect of drugs on bloodstream forms in mice with established T. cruzi infections. The results obtained with this method show a fairly good correlation with those obtained by prolonged treatment schedules used to assess the action of drugs in experimental Chagas' disease and may be used to study the sensitivity of T. cruzi strains to active drugs.

Active cutaneous leishmaniasis in Brazil, induced by Leishmania donovani chagasi

L.d. chagasi was isolated from active cutaneous leishmaniasis in both human and canine infections in an endemic area in Rio de Janeiro, Brazil. Both isolates were identified by molecular and immunological characterization of the parasite using three different methods: electrophoretic mobility of isoenzymes; restriction endonuclease fragment analysis of kDNA and serodeme analysis using monoclonal antibodies. This seems to be the first well documented case in the New World of a "viscerotropic" Leishmania inducing a case of cutaneous leishmaniasis. This observation emphasizes that the diagnosis of the etiologic agent of human or canine visceral leishmaniasis based solely upon clinical and epidemiological critwria may lead to erroneous conclusions.

Potential sources of biodynamically active natural products in Brazil

In contrast to China where vegatation is predominantly herbaceous, vegetation in Brazil is commonly arboreous. This fact may explain why Chinese drugs are usually acetate derived, while actual and potential natural therapeutic agents from Brazil are mostly shikimate derived. Only relatively few compounds isolated from Brazilian plants have been submitted to adequate pharmacological testing

An in vitro system from Plasmodium falciparum active in endogenous mRNA translation

An in vitro translation system has been prepared from Plasmodium falciparum by saponin lysis of infected-erythrocytes to free parasites which were homogeneized with glass beads, centrifuged to obtain a S-30 fraction followed by Sephadex G-25 gel filtration. This treatment produced a system with very low contamination of host proteins (<1%). The system, optimized for Mg2+ and K+, translates endogenous mRNA and is active for 80 min which suggests that their protein factors and mRNA are quite stable.

Future trypanosomatid phylogenies: refined homologies, supertrees and networks

There has been good progress in inferring the evolutionary relationships within trypanosomes from DNA data as until relatively recently, many relationships have remained rather speculative. Ongoing molecular studies have provided data that have adequately shown Trypanosoma to be monophyletic and, rather surprisingly, that there are sharply contrasting levels of genetic variation within and between the major trypanosomatid groups. There are still, however, areas of research that could benefit from further development and resolution that broadly fall upon three questions. Are the current statements of evolutionary homology within ribosomal small sub-unit genes in need of refinement? Can the published phylograms be expanded upon to form `supertrees' depicting further relationships? Does a bifurcating tree structure impose an untenable dogma upon trypanosomatid phylogeny where hybridisation or reticulate evolutionary steps have played a part? This article briefly addresses these three questions and, in so doing, hopes to stimulate further interest in the molecular evolution of the group.

Expression of mosquito active toxin genes by a Colombian native strain of the gram-negative bacterium Asticcacaulis excentricus

Mosquito control with biological insecticides, such as Bacillus sp. toxins, has been used widely in many countries. However, rapid sedimentation away from the mosquito larvae feeding zone causes a low residual effect. In order to overcome this problem, it has been proposed to clone the Bacillus toxin genes in aquatic bacteria which are able to live in the upper part of the water column. Two strains of Asticcacaulis excentricus were chosen to introduce the B. sphaericus binary toxin gene and B. thuringiensis subsp. medellin cry11Bb gene cloned in suitable vectors. In feeding experiments with these aquatic bacteria, it was shown that Culex quinquefasciatus, Aedes aegypti, and Anopheles albimanus larvae were able to survive on a diet based on this wild bacterium. A. excentricus recombinant strains were able to express both genes, but the recombinant strain expressing the B. sphaericus binary toxin was toxic to mosquito larvae. Crude protease A. excentricus extracts did not degrade the Cry11Bb toxin. The flotability studies indicated that the recombinant A. excentricus strains remained in the upper part of the water column longer than the wild type Bacillus strains.

Coevolutionary networks: a novel approach to understanding the relationships of humans with the infectious agents

Human organism is interpenetrated by the world of microorganisms, from the conception until the death. This interpenetration involves different levels of interactions between the partners including trophic exchanges, bi-directional cell signaling and gene activation, besides genetic and epigenetic phenomena, and tends towards mutual adaptation and coevolution. Since these processes are critical for the survival of individuals and species, they rely on the existence of a complex organization of adaptive systems aiming at two apparently conflicting purposes: the maintenance of the internal coherence of each partner, and a mutually advantageous coexistence and progressive adaptation between them. Humans possess three adaptive systems: the nervous, the endocrine and the immune system, each internally organized into subsystems functionally connected by intraconnections, to maintain the internal coherence of the system. The three adaptive systems aim at the maintenance of the internal coherence of the organism and are functionally linked by interconnections, in such way that what happens to one is immediately sensed by the others. The different communities of infectious agents that live within the organism are also organized into functional networks. The members of each community are linked by intraconnections, represented by the mutual trophic, metabolic and other influences, while the different infectious communities affect each other through interconnections. Furthermore, by means of its adaptive systems, the organism influences and is influenced by the microbial communities through the existence of transconnections. It is proposed that these highly complex and dynamic networks, involving gene exchange and epigenetic phenomena, represent major coevolutionary forces for humans and microorganisms.