Imunização contra malária: perspectivas e desafios / Malaria immunization: prospects and challenges

O referido trabalho tem como objetivo analisar e avaliar a atual conjuntura das pesquisas científicas na busca da imunização eficaz contra a malária, destacando os principais mecanismos imunológicos e moleculares subjacentes à referida proteção, bem como, as perspectivas a curto e médio prazo. O presente estudo de revisão selecionou pesquisas nas bases de dados da Medical Literature Analysis and Retrieval System Online (Medline), National Library of Medicine (Pubmed), Scientific Electronic Library Online (SciELO), Web of Science e Scopus. Foram combinados os termos Malaria, Immunization, Vaccine and Epidemiology, com seus sinônimos remissivos e outros descritores associados, no período compreendido entre janeiro e julho de 2019. Como fator preponderante dos critérios de inclusão, foram selecionadas revisões sistemáticas com ou sem metanálise, publicadas nos últimos 5 anos, que discorressem detalhadamente sobre o tema, ou que apresentassem informações estatísticas ou históricas relevantes, relacionada ao tema. Como critérios de exclusão foram considerados: materiais literários e científicos, anteriores ao período de 2014 e que não apresentassem informações estatísticas ou histórica relevantes ao tema, ou que, não se adequassem à temática da pesquisa. Após a aplicação dos critérios de inclusão e exclusão, foi realizada a análise e seleção dos artigos. Dos 451 artigos identificados, 44 foram selecionados. As informações extraídas dos referidos trabalhos convergem no sentido de que a erradicação da malária é uma tarefa demasiadamente complexa, a qual não será alcançada com as vacinas atuais, havendo necessidade do desenvolvimento de ferramentas imunizadoras de maior eficácia. Apesar dos esforços, atualmente ainda não existe uma vacina eficaz na prevenção da infecção, mas vários estudos se encontram em andamento nessa vertente, tornando promissor o surgimento de uma vacina eficaz contra o parasita.

This study aims at analyzing and evaluating the current status of scientific research in the search for effective immunization against malaria, highlighting the key immunological and molecular mechanisms of such protection and the short- and medium-term perspectives. The search and selection of studies took place in the databases of the Medical Literature Analysis and Retrieval System Online (Medline); National Library of Medicine (Pubmed); Scientific Electronic Library Online (SciELO); Web of Science; and Scopus. The terms Malaria, Immunization, Vaccine, and Epidemiology were used, with their corresponding cross-referenced synonyms and other associated descriptors, including the period from January to July 2019. As a main factor in the inclusion criteria, systematic reviews with or without meta-analysis published in the last 5 years, presenting a detailed discourse about the topic, or relevant statistical or historical information related to the topic were selected. The following exclusion criteria were considered: literary and scientific materials, prior to 2014, and without statistical or historical information relevant to the theme, or which did not fit the research theme. After applying the inclusion and exclusion criteria, the articles were analyzed and selected. From a total of 451 identified articles, 44 were selected. The information extracted from the referred studies converge in the sense that malaria eradication is an overly complex task, which will not be achieved with the current vaccines, requiring the development of more effective immunizing tools. Despite all the efforts, there is no effective vaccine for preventing infection yet, but several studies are being developed in this area, making the emergence of an effective vaccine against the disease promising.

Vigilancia de paludismo en Argentina: 2005-2018 / Malaria surveillance in Argentina: 2005-2018

El paludismo o malaria es una enfermedad potencialmente mortal causada por la infección de una o más de cinco especies de parásitos protozoarios intracelulares: Plasmodium vivax, Plasmodium falciparum, Plasmodium ovale, Plasmodium malariae, y Plasmodium knowlesi, que se transmiten al ser humano por la picadura de mosquitos hembra infectados del género Anopheles. Se describen antecedentes, situación actual, casos notificados en Argentina, estratificación de riesgo de reintroducción de paludismo en el país, definición de casos sospechosos y confirmados, y acciones epidemiológicas realizadas

Homeopathic treatment as an alternative prophylactic to minimize bacterial infection and prevent neonatal diarrhea in calves.

Bovine neonatal diarrhea is common due low immunity in newborn calves, poor management (or absence) of sanitary barriers, and other factors. Newborn calves with diarrhea in the first days of life suffer failure to thrive and may die if left untreated. The aim of this study was to evaluate whether prophylactic administration of a homeopathic product (Dia 100®) can control bovine neonatal diarrhea in calves born on a farm with substantial sanitary challenges. We counted total bacteria and protozoan parasites in fecal samples. We measured serum glucose, total protein, globulin, albumin, cholesterol and triglycerides on days 1, 7 and 14 of life. Twenty newborn calves were maintained in individual stalls, and were divided in two groups: ten untreated animals (control) and ten animals treated with Dia 100®. Fecal consistency was evaluated daily. We diagnosed diarrhea in five animals in the treated group, and in all animals from the control group. Infections with Escherichia coli and Giardia duodenalis were identified as the responsible organisms. The E. coli count was low in the treatment group on day 7 of life compared with the control group. Antibiotics were given to eight animals in the control group, and to two animals in the treatment group. On day of life 7, serum levels of total protein and globulins were higher in the control group, but were lower on day 14. Serum levels of glucose and triglycerides were greater in treated animals on days 7 and 14, suggesting that the homeopathic product contributes to improvement of intestinal health and absorption and nutrients. We conclude that Dia 100® controls diarrhea with 50% of efficacy, and reduces antibiotic utilization.

Leishmaniose visceral canina e sua importância na saúde pública: revisão de literatura / Canine Leishmania Infections and its importance in public health: review / Leishmaniasis Visceral Canina y su importancia en la salud pública: revisión de literatura

La Leishmaniasis Visceral Canina es causada por un género Leishmania y se transmite por la picadura de una especie de Flebotomídeo,Lutzomyia longipalpis comúnmente conocido como Tatuquira o Birigui. La razón de que la enfermedad empezar a aparecer en las principales ciudades lleva nos a la discusión de nuevas estrategias de prevención y control, como todas las medidas utilizadas hasta hoy no han sido capaces de erradicar la transmisión y prevenir la aparición de nuevos brotes. En esta revisión de la literatura se discutirá patogénesis, medios de transmisión, síntomas clínicos, métodos diagnósticos, prevención y posible tratamiento de perros infectados. También se discute la política de eliminación de los perros como método de control de la transmisión de Canine Leishmaniasis.

Canine Visceral Leishmaniasis is caused by a genus Leishmania and transmitted through the bite of a species Flebotomídeo Lutzomyialongipalpiscommonly known as Mosquito - straw, Tatuquira or Birigui. Some control measures implemented so far have been unable to eliminate transmission and prevent the occurrence of new epidemics, however, the increasing urbanization of the disease brings forth the discussion of prevention and control strategies. In this literature review is to discuss on the pathogenesis, transmission means, clinical symptoms, diagnostic methods, methods of prevention and possible treatment of infected dogs. Also discusses the dogs disposal policy and method of controlling the transmission of Canine Visceral Leishmaniasis.

A Leishmaniose Visceral Canina é causada por um protozoário do gênero Leishmania e transmitida através da picada de um Flebotomídeo da espécieLutzomyia longipalpiscomumente conhecido como Mosquito-Palha, Tatuquira ou Birigui. O fato de a doença começar a aparecer nas grandes cidades traz à tona a discussão de novas estratégias de prevenção e controle, pois todas as medidas utilizadas até hoje não foram capazes de erradicar a transmissão e evitar a ocorrência de novas epidemias. Nesta revisão de literatura será abordadaa patogenia, meios de transmissão, sintomas clínicos, métodos de diagnóstico, bem como métodos de prevenção e possíveis tratamentos de cães infectados. Discute-se também a política de eliminação de cães como método de controle da transmissão da Leishmaniose.

Leishmaniose visceral canina e sua importância na saúde pública: revisão de literatura / Canine Leishmania Infections and its importance in public health: review / Leishmaniasis Visceral Canina y su importancia en la salud pública: revisión de literatura

La Leishmaniasis Visceral Canina es causada por un género Leishmania y se transmite por la picadura de una especie de Flebotomídeo,Lutzomyia longipalpis comúnmente conocido como Tatuquira o Birigui. La razón de que la enfermedad empezar a aparecer en las principales ciudades lleva nos a la discusión de nuevas estrategias de prevención y control, como todas las medidas utilizadas hasta hoy no han sido capaces de erradicar la transmisión y prevenir la aparición de nuevos brotes. En esta revisión de la literatura se discutirá patogénesis, medios de transmisión, síntomas clínicos, métodos diagnósticos, prevención y posible tratamiento de perros infectados. También se discute la política de eliminación de los perros como método de control de la transmisión de Canine Leishmaniasis.(AU)

Canine Visceral Leishmaniasis is caused by a genus Leishmania and transmitted through the bite of a species Flebotomídeo Lutzomyialongipalpiscommonly known as Mosquito - straw, Tatuquira or Birigui. Some control measures implemented so far have been unable to eliminate transmission and prevent the occurrence of new epidemics, however, the increasing urbanization of the disease brings forth the discussion of prevention and control strategies. In this literature review is to discuss on the pathogenesis, transmission means, clinical symptoms, diagnostic methods, methods of prevention and possible treatment of infected dogs. Also discusses the dogs disposal policy and method of controlling the transmission of Canine Visceral Leishmaniasis.(AU)

A Leishmaniose Visceral Canina é causada por um protozoário do gênero Leishmania e transmitida através da picada de um Flebotomídeo da espécieLutzomyia longipalpiscomumente conhecido como Mosquito-Palha, Tatuquira ou Birigui. O fato de a doença começar a aparecer nas grandes cidades traz à tona a discussão de novas estratégias de prevenção e controle, pois todas as medidas utilizadas até hoje não foram capazes de erradicar a transmissão e evitar a ocorrência de novas epidemias. Nesta revisão de literatura será abordadaa patogenia, meios de transmissão, sintomas clínicos, métodos de diagnóstico, bem como métodos de prevenção e possíveis tratamentos de cães infectados. Discute-se também a política de eliminação de cães como método de controle da transmissão da Leishmaniose.(AU)

Protozoan infections in farmed fish from Brazil: diagnosis and pathogenesis / Infecções por protozoários em peixes cultivados no Brasil: diagnóstico e patogênese

The Phylum Protozoa brings together several organisms evolutionarily different that may act as ecto or endoparasites of fishes over the world being responsible for diseases, which, in turn, may lead to economical and social impacts in different countries. Apart from the recent advances for the diagnosis of fish diseases in Brazil, little is known on the protozoan parasites and their relationship with environment and host. This revision presents the most important protozoan parasites found in farmed fish from Brazil, not only with emphasis on its diagnosis, biology, transmission and host-parasite relationship, but also on some information that may be useful to researchers in determining the correct diagnosis in fish farms.(AU)

O filo Protozoa reúne diversos organismos evolutivamente distintos que podem atuar como ecto ou endoparasitos de peixes em todo o mundo, sendo responsáveis por doenças as quais, por sua vez, podem ocasionar impactos econômico e social nos diferentes países. Apesar dos recentes avanços no campo de diagnóstico de doenças em peixes no Brasil, ainda pouco se conhece sobre a fauna de protozoários parasitos de peixes e suas relações com o ambiente e hospedeiro. Esta revisão apresenta os mais importantes protozoários parasitos encontrados em peixes cultivados no Brasil, não apenas com ênfase no seu diagnóstico, biologia, transmissão e relação hospedeiro-parasito, mas também algumas informações que podem ser úteis para pesquisadores para o correto diagnóstico em pisciculturas.(AU)

Dramatic decrease in prevalence of soil-transmitted helminths and new insights into intestinal protozoa in children living in the Chaco region, Bolivia.

We assessed the prevalence of intestinal parasites among 268 2-12-year-old children living in rural areas, small villages, and semi-urban areas of the Chaco region, south-eastern Bolivia. The overall parasitism was 69%. Only protozoa, helminths, or co-infections were observed in 89.2%, 5.9%, or 4.9% of the positive children, respectively. A significant progressive increase in overall parasite prevalence was found when passing from rural areas to small villages and semi-urban areas. The most commonly found species were Entamoeba coli (38.4%), Giardia intestinalis (37.7%), and Blastocystis spp. (16%). Hymenolepis nana was the most prevalent helminth (5.6%), followed by Ascaris lumbricoides and hookworms (1.5% and 0.4%) evidenced only in rural areas and in villages. Molecular diagnostics identified Blastocystis subtypes 9 and 2, and 5 infections by Entamoeba histolytica and 4 by Entamoeba dispar. The dramatic decrease in prevalence of soil-transmitted helminths with respect to that observed about 20 years ago (> 40%) evidences the success of the preventive chemotherapy intervention implemented in 1986. Health education and improved sanitation should be intensified to control protozoan infections.

Enteroparasite contamination in peridomiciliar soils of two indigenous territories, State of Paraná, southern Brazil.

OBJECTIVES: To determine 1) the degree of soil contamination by parasites; 2) the prevalence of contaminated samples; 3) the overall number of parasitic forms, by distance between the collection site and the domicile; 4) the mean number of parasite forms per peri-household area; and 5) the variables associated with the total number of parasite forms. METHODS: Soil samples were collected in the peridomicile of 18 (out of a total sample of 63) and 22 (out of 190) residences of the Faxinal and Ivaí indigenous territories (ITs), respectively, from March 2005 through October 2006, and evaluated by the methods of Baermann, modified Faust et al., and Lutz. RESULTS: The overall prevalence of samples contaminated by enteroparasites of humans or of animals with zoonotic potential was 75.7% (84 out of 111) in Faxinal and 96.2% (127 out of 132) in Ivaí. The most prevalent parasites were Ascaris spp., Isospora spp., and Toxocara spp. Positive statistical associations were observed between the number of parasitic forms per domicile and the following variables: time of year (season), the presence of bathrooms in the domicile, and the presence of excrement on peridomiciliar soil. CONCLUSIONS: The high level of soil contamination in Faxinal and Ivaí 1) constitutes a potential source of parasitic infection and 2) suggests that the treatment of human and animal excreta continues to be inadequate.

Enteroparasite contamination in peridomiciliar soils of two indigenous territories, State of Paraná, southern Brazil / Contaminación por enteroparásitos en el suelo peridomiciliar de dos territorios indígenas del estado de Paraná, en el sur del Brasil

OBJECTIVES: To determine 1) the degree of soil contamination by parasites; 2) the prevalence of contaminated samples; 3) the overall number of parasitic forms, by distance between the collection site and the domicile; 4) the mean number of parasite forms per peri-household area; and 5) the variables associated with the total number of parasite forms. METHODS: Soil samples were collected in the peridomicile of 18 (out of a total sample of 63) and 22 (out of 190) residences of the Faxinal and Ivaí indigenous territories (ITs), respectively, from March 2005 through October 2006, and evaluated by the methods of Baermann, modified Faust et al., and Lutz. RESULTS: The overall prevalence of samples contaminated by enteroparasites of humans or of animals with zoonotic potential was 75.7 percent (84 out of 111) in Faxinal and 96.2 percent (127 out of 132) in Ivaí. The most prevalent parasites were Ascaris spp., Isospora spp., and Toxocara spp. Positive statistical associations were observed between the number of parasitic forms per domicile and the following variables: time of year (season), the presence of bathrooms in the domicile, and the presence of excrement on peridomiciliar soil. CONCLUSIONS: The high level of soil contamination in Faxinal and Ivaí 1) constitutes a potential source of parasitic infection and 2) suggests that the treatment of human and animal excreta continues to be inadequate.

OBJETIVOS: Determinar: 1) el grado de contaminación parasitaria del suelo; 2) la prevalencia de muestras contaminadas; 3) el número general de formas parasitarias, en función de la distancia entre el sitio donde se tomaron las muestras y el domicilio; 4) el número promedio de formas parasitarias por área peridomiciliar y 5) las variables relacionadas con el número total de formas parasitarias. MÉTODOS: Se recogieron muestras del suelo de los alrededores de 18 (de una muestra total de 63) y 22 domicilios (de una muestra total de 190) situados en los territorios indígenas Faxinal e Ivaí, respectivamente, entre marzo del 2005 y octubre del 2006. Las muestras se evaluaron mediante los métodos propuestos por Baermann, Faust et al. (modificado) y Lutz. RESULTADOS: La prevalencia general de las muestras contaminadas por enteroparásitos humanos o animales que se consideraron de potencial zoonótico fue de 75,7 por ciento (84 de 111) en Faxinal y de 96,2 por ciento (127 de 132) en Ivaí. Las especies de parásitos más prevalentes fueron Ascaris, Isospora y Toxocara. Se observó una asociación estadística positiva entre el número de formas parasitarias halladas en los alrededores de cada domicilio y las siguientes variables: la época del año (estación), la existencia de baños domiciliarios y el hallazgo de excremento en el suelo peridomiciliar. CONCLUSIONES: La gran contaminación del suelo hallada en Faxinal e Ivaí constituye una posible fuente de infección parasitaria e indica que sigue siendo insuficiente el tratamiento de los excrementos de seres humanos y animales.

Effects of vitamin A supplementation on intestinal barrier function, growth, total parasitic, and specific Giardia spp infections in Brazilian children: a prospective randomized, double-blind, placebo-controlled trial.

BACKGROUND: This study evaluates the effects of retinol on intestinal barrier function, growth, total parasites, and Giardia spp infections in children in northeastern Brazil. SUBJECTS AND METHODS: The study was a double-blind, randomized placebo-controlled trial (http://clinicaltrials.gov; register no. #NCT00133406) involving 79 children who received vitamin A 100,000-200,000 IU (n = 39) or placebo (n = 40) at enrollment, 4, and 8 months and were followed for 36 months. Intestinal barrier function was evaluated using the lactulose:mannitol ratio test. Stool lactoferrin was used as a marker for intestinal inflammation. RESULTS: The groups were similar with regard to age, sex, nutritional parameters (z scores), serum retinol concentrations, proportion of lactoferrin-positive stool samples, and intestinal barrier function. The lactulose:mannitol ratio did not change during the same time of follow-up (P > 0.05). The proportion of lactoferrin-positive samples evaluated at 1 month did not change between groups (P > 0.05). Total intestinal parasitic, specifically new, infections were significantly lower in the vitamin A treatment compared with control group; these were accounted for entirely by significantly fewer new Giardia infections in the vitamin A treatment group. The cumulative z scores for weight-for-length or height, length or height-for-age z scores, and weight-for-age did not change significantly with vitamin A intervention for 36 months of follow-up. CONCLUSIONS: These data showed that total parasitic infection and Giardia spp infections were significantly lower in the vitamin A treatment group when compared with the placebo group, suggesting that vitamin A improves the host's defenses against Giardia infections.

Association between seropositivity for Neospora caninum and reproductive performance of beef heifers in the Pantanal of Mato Grosso do Sul, Brazil / Associação entre soropositividade para Neospora caninum e o desempenho reprodutivo de novilhas de corte no Pantanal Sul-Mato-Grossense, Brasil

Neospora caninum is an obligate intracellular parasite that can infect domestic and wild canids, ruminants, and horses. he purpose of this study was to evaluate the association between the presence of antibodies to N. caninum and reproductive loss in beef heifers in the South Pantanal region of Mato Grosso, Brazil. A total of 1098 heifers were evaluated from breeding to calving with regard to reproductive performance, and serology for neosporosis was assayed by indirect immunoluorescence reaction. he prevalence of N. caninum in cows that had failed to conceive was 22.13% higher than in those that had conceived (p < 0.0001), indicating a signiicant correlation between non-conception and presence of anti-N. caninum antibodies. he extraction rates for seropositive and seronegative heifers were 28.24 and 50.12%, respectively, with a statistically signiicant value (p < 0.0001) that showed a decrease of 44% in the extraction rate of seropositive animals. he results emphasize the importance of diagnosis for monitoring of neosporosis in primiparous cows, and indicators of seropositive females as a factor in strategies for culling the beef cattle herd.(AU)

Neospora caninum é um parasita intracelular obrigatório que pode infectar canídeos domésticos e selvagens, ruminantes e equídeos. Neste trabalho estudou-se a associação entre soropositividade para Neospora caninum e perda reprodutiva em novilhas de corte na região do Pantanal Sul-Mato-Grossense. Foram avaliadas 1098 novilhas da estação de reprodução ao nascimento dos bezerros com relação ao desempenho reprodutivo e realizada a sorologia para N. caninum através da reação de imunofluorescência indireta. A soroprevalência de N. caninum nas vacas que falhara na concepção foi 22,13% maior que nas que conceberam (p < 0,0001), indicando que há uma correlação significativa entre a não concepção e a presença de anticorpos anti-N. caninum. As taxas de desfrute para as novilhas soropositivas e soronegativas para neosporose foram de 28,24 e 50,12%, respectivamente, mostrando uma redução de 44% na taxa de desfrute de novilhas soropositivas para N. caninum. Ressalta-se a importância do monitoramento do diagnóstico da neosporose em primíparas, e o indicador de fêmeas soropositivas como um fator nas estratégias de descarte no rebanho bovino de corte.(AU)

Risk factors associated with Tritrichomonas foetus infection in beef herds in the Province of Buenos Aires, Argentina.

Bovine trichomonosis (BT) is a contagious disease, characterized by reproductive failure, embryonic losses, infertility, and abortions, which directly impacts the reproductive performance of cattle. In this cross-sectional questionnaire-based study, 56 veterinarians provided information on the geographic location and on the demographic, husbandry, and sanitary characteristics of 173 beef herds located in 26 (21%) counties of the Province of Buenos Aires, Argentina. Herds rearing beef cattle (OR=2.5, 95% CI=1.0, 6.3), with low pregnancy rate in cows (

Prevalence and risk factors for protozoan and nematode infections among children in an Ecuadorian highland community.

In order to create a parasite prevention program for Santa Ana, Ecuador, we worked with local physicians to identify the prevalence and risk factors for intestinal parasitic infection among children. Two hundred households were randomly selected and asked to submit three stool samples from a selected child. Information from direct observation and questionnaires was used to determine environmental and behavioral risk factors for parasitic infection. Prevalence of any parasitic infection was 65.6% of the 189 children who submitted fecal samples. Parasitic infections included Entamoeba histolytica/E. dispar (46.6%), Giardia lamblia (18.5%) and Ascaris lumbricoides (20.1%). In a multivariate logistic model, risk factors (P<0.05) for E. histolytica/E. dispar included >1 month since antiparasitic treatment, not adding chlorine to drinking water, children not washing their hands before eating, and having a fewer number of electrical appliances in the home. The risk factor identified for G. lamblia was children not washing their hands before eating. Risk factors for A. lumbricoides included >6 months since antiparasitic treatment and having a fewer number of electrical appliances in the home. This study may have implications for other communities throughout the developing world.

Immunization in heifers with dual vaccines containing Tritrichomonas foetus and Campylobacter fetus antigens using systemic and mucosal routes.

Vaccines against both bovine venereal campylobacteriosis and trichomonosis were tested. Heifers were assigned to three groups. Groups 1 (n = 21 heifers) and group 2 (n = 20) received a commercial or experimental vaccine, respectively, containing both Campylobacter fetus and Tritrichomonas foetus antigens. Group 3 (n = 21) received adjuvant alone. Preparations were injected SQ in groups 1 and 3 at days -60 and -30 (day 0 was considered the first day of a 90-day breeding period), and in group 2 SQ at days -30 and +11 and into the vaginal submucosa at day -9. Heifers were exposed to two pathogen-infected bulls for 90 days (from day 0 to day +90); furthermore, half of the heifers in each group were challenged at day +39 by an intravaginal instillation of C. fetus venerealis and T. foetus. Pregnancy diagnosis, vaginal culture, and determination of systemic IgG for both organisms were performed. Compared to controls, vaccinated heifers resisted or quickly cleared both pathogens, had a higher pregnancy rate and a higher systemic immune response during and after the breeding period. Overall, the experimental vaccine was superior to the commercial vaccine (groups 2 and 1, respectively). In conclusion, an experimental vaccine containing both C. fetus and T. foetus antigens, given both SQ and intravaginal immediately before breeding and early in the breeding season, yielded superior protection for heifers exposed to bulls harboring C. fetus and T. foetus.

Heifers immunized with whole-cell and membrane vaccines against Tritrichomonas foetus and naturally challenged with an infected bull.

The performance of a whole-cell vaccine and the other vaccine with cellular membranes of Tritrichomonas foetus applied to heifers naturally challenged by mating with an infected bull was determined. Forty heifers were divided into three groups: a control group (n=16) without immunizing, another group (n=12) immunized with whole cells (10(8)/dose) and a third group (n=12) immunized with cellular membranes (300 micro g of membranes/dose protein). The females were subcutaneously vaccinated at 3-week on two occasions and received a third intravaginal booster dose. After 3 weeks of the last vaccinal doses, the heifers were served by a T. foetus infected bull over 90-day period. The mean duration of infection for membrane-vaccinated heifers was 60 days +/-25, compared with 63 days +/-35.8 of infection for whole-cell-vaccinated heifers and 79 days +/-41.3 for control heifers. Calving rates were 6/12 for membrane-vaccinated heifers, 3/12 for whole-cell-vaccinated animals, and 2/16 for control animals. Fetal mortality rates were 3/12 for membrane-vaccinated animals, 4/12 for those vaccinated with whole cells and 10/16 for control animals. These reproductive parameters were significantly different (P<0.05) between heifers vaccinated with membranes and control heifers. The hemolytic test and enzyme-linked immunoabsorbent assay (ELISA) with T. foetus antigen showed that serum immunoglobulins peaked before and during the breeding period. The heifers vaccinated with membranes developed an important response during the critical period of fetal loss, second and third month of the breeding time, and another month after the same period. The ELISA method was more sensitive and more reliable than the hemolytic test for the evaluation of the systemic immune response in females infected and/or vaccinated with T. foetus.

[Phosphorylation in eukaryotic cells. Role of phosphatases and kinases in the biology, pathogenesis and control of intracellular and bloodstream protozoa]. / Fosforilación en células eucarióticas. Papel de fosfatasas y quinasas en la biología, patogenia y control de protozoosis tisulares y sanguíneas.

Cells respond to environmental or cellular changes, rapidly switching protein activities from one state to another. In eukaryotes, a way to achieve these changes is through protein phosphorylation cycles, involving independent protein kinase and protein phosphatase activities. Current evidences show that phosphatases and kinases are also involved in the molecular basis of immune response and in disease such as diabetes obesity and Alzheimer. In protozoan parasites like Trypanosoma and Leishmania, several kinases and phosphatases have been identified, many of them have been cloned but in several cases their biological role remains undetermined. In this review, the state-of-the art is summarized and the role of phosphatases and kinases in biological phenomena such as remodeling, invasion and pathogenic capacity of protozoan parasites is described. The real chance to use these components of signal transduction pathways as target for chemotherapeutic intervention is also discussed (Rev Méd Chile 2000; 128: 1150-60).

Effects of Polysispyrenia simulii (Microspora; Duboscqiidae) on development of the gonads of Simulium pertinax (Diptera; Simuliidae)

The effects of the infection caused by the microsporidium Polydispyrenia simulii in gonads of the simuliid Simulium pertinax were evaluated. This blackfly species is the main target of control programmes in southeastern Brazil. Infected and noninfected blackflies were reared from larval stage to adults using a laboratory rearing system. There was no significant difference between the oogenic development and dimensions of ovarian follicles of healthy females compared to those reared from infected larvae. Otherwise, there was a significant difference between the fecundity of healthy females and those reared from infected larvae. In males, there was an evident recuction of motility of spermatozoids of males reared from infected larvae. The results obtained suggest that the microsporidium P. simulii have an important effect on the natural population dynamics of S. pertinax.