Craniometric geographical variation in Hylaeamys megacephalus populations / Variação geográfica craniométrica em populações de Hylaeamys megacephalus

Hylaeamys megacephalus (G. Fisher, 1814) presents great genetic diversity and wide geographical distribution, and occurs in both the Amazon and Cerrado biomes. Because of its generalist aspect, this species tolerates different eating habits and habitats. It occurs in flooded and dry areas and is predominantly terrestrial, which allows greater gene flow between populations even over long distances. Studies that seek a better understanding of morphological variations resulting from differences imposed by the environment throughout this species' distribution are still lacking. This study aimed to analyze the differences between H. megacephalus populations based on craniometry, investigating whether the environment has an influence on morphology. We analyzed a total of 142 specimens from three scientific mammal collections: National Museum, "Universidade Federal do Rio de Janeiro" (MN-UFRJ); "Laboratório de Biologia e Parasitologia de Mamíferos Reservatórios Silvestres", "Instituto Oswaldo Cruz", "Fundação Oswaldo Cruz"(LBCE-Fiocruz); and "Laboratório de Biodiversidade", "Universidade Federal de Goiás", "Regional Jataí" (LZE-UFG), and took 20 craniometric measurements. Craniometry was explored using unweighted pair group method with arithmetic mean (UPGMA), canonical variate analysis, and principal component analysis (PCA). The results led us to conclude that there are three craniometric groups of H. megacephalus with a tendency to differentiate as a result of geographical influences.(AU)

Com grande diversidade genética e distribuição geográfica, Hylaeamys megacephalus (G. Fisher, 1814) ocorre tanto na Amazônia quanto no Cerrado. Visto seu aspecto generalista, esta espécie tolera diversos hábitos alimentares e habitats, ocorrendo em áreas inundadas ou não, sendo predominantemente terrestre, permitindo maior fluxo de genes entre as populações, mesmo em longas distâncias. Apresenta ampla distribuição, e carece de estudos que busquem um melhor entendimento sobre as variações morfológicas resultantes das diferenças impostas pelo meio ao longo de sua distribuição. O estudo teve como objetivo, analisar as diferenças entre as populações de H. megacephalus, com base na craniometria investigando se o ambiente interfere na morfologia. Analisamos um total de 142 espécimes oriundos de coleções científicas de mamíferos, do Museu Nacional, Universidade Federal do Rio de Janeiro (MN-UFRJ), Laboratório de Biologia e Parasitologia de Mamíferos Reservatórios Silvestres, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (LBCE-Fiocruz) e Laboratório de Biodiversidade, Universidade Federal de Goiás, Regional Jataí, nos quais foram tomadas 20 medidas craniométricas. A craniometria foi explorada nas análises estatísticas de agrupamento de pares não ponderados com médias aritméticas (UPGMA), variação canônica e análise dos Componentes Principais (PCA). Os resultados encontrados nos levaram a concluir a existência de três grupos craniométricos da espécie de H. megacephalus com tendência a se diferenciarem, por influências geográficas.(AU)

Helminthic infection in three native rodent species from a semiarid Mediterranean ecosystem / Infecção por helmintos em três espécies de roedores nativos em um ecossistema mediterrâneo

Abstract Helminth parasites are still not a well-known component of animal biodiversity. In this study, we describe and compare the endoparasite assemblages of three native rodent species from a semiarid Mediterranean ecosystem. A total of eight species of gastrointestinal helminth parasites were detected. The endoparasitic communities of the rodents Phyllotis darwini (5 species), Octodon degus (4 species), and Abrothrix olivaceus (3 species) were described in terms of their prevalence and mean abundance. In addition, endoparasite records by rodent species were submitted to rarefaction analyses to verify sampling robustness and used to compare richness and similarity among rodent species. O. degus presented the highest prevalence and parasitic load, but was of low diversity, while P. darwini presented the highest diversity, but had a low prevalence rate. Conversely, A. olivaceus presented the lowest prevalence and diversity. This study contributes to the existing knowledge of the endoparasitic fauna of rodent species from semiarid Mediterranean zones.

Resumo Os helmintos parasitas não são um componente ainda bem conhecido da biodiversidade animal. Neste trabalho, descreveu-se e comparou-se as redes de endoparasitas de três espécies de roedores nativos de um ecossistema mediterrâneo semiárido. No estudo foram detectadas um total de oito de espécies de helmintos gastrointestinais parasitas. As comunidades endoparasíticas dos roedores Phyllotis darwini (5 espécies), Octodon degus (4 espécies) e Abrothrix olivaceus (3 espécies) foram descritas por meio da sua prevalência e abundância média. Além disso, os registros de endoparasitas achados nas diferentes espécies de roedores foram submetidos a uma análise de rarefação para verificar a robustez da amostragem, e utilizados para comparar a riqueza e a similaridade entre espécies de roedores. Octodon degus apresentou a maior prevalência e carga parasitária, menor diversidade, enquanto P. darwini apresentou a maior diversidade, mas uma baixa prevalência. Porém, A. olivaceus apresentou a menor prevalência e diversidade de parásitas. Este estudo representa uma contribuição ao conhecimento da fauna endoparasitária das espécies de roedores próprias das zonas semi-áridas do Mediterrâneo chileno.

Litomosoides silvai (Nematoda: Onchocercidae) parasitizing Akodon montensis (Rodentia: Cricetidae) in the southern region of Brazil / Litomosoides silvai (Nematoda: Onchocercidae) parasitando Akodon montensis (Rodentia: Cricetidae) na região Sul do Brasil

Abstract In the present study, Litomosoides silvai parasitizing Akodon montensis in the southern region of Brazil is reported for the first time. New morphological information is provided for some structures of this nematode species, such as a flattened cephalic extremity, presence of two dorsal cephalic papillae, female tail with a constriction at its tip, "s" shaped vagina, spicules characteristic of the carinii species group and microfilaria tail constricted at the tip. This nematode was found parasitizing the thoracic cavity with a prevalence of 10% (2/20), mean intensity of 4 (6/2), mean abundance of 0.4 (8/20) and range of infection of 2-6 specimens per host, in southern Brazil. This occurrence of L. silvai in A. montensis is a new geographical record for southern Brazil, in the Upper Paraná Atlantic Forest ecoregion of the northwestern region of Rio Grande do Sul, which is part of the Atlantic Forest biome.

Resumo No presente estudo é relatado pela primeira vez Litomosoides silvai parasitando Akodon montensis coletados na região Sul do Brasil. Foram fornecidas novas informações morfológicas para algumas estruturas desta espécie de nematódeo, tais como extremidade cefálica achatada, a presença de duas papilas cefálicas dorsais, cauda das fêmeas com uma constrição na ponta da cauda, vagina em forma de "s", espículas de característica do grupo de espécies de carinii e cauda da microfilária com constrição na ponta. Este nematódeo parasitava a cavidade torácica com uma prevalência de 10% (2/20), intensidade média de 4 (8/2) e abundância média de 0,4 (8/20), e intervalo de infecção de 2-6 espécimes por hospedeiro no Sul do Brasil. A ocorrência de L. silvai em A. montensis é um novo registro geográfico, no sul do Brasil, a noroeste do estado do Rio Grande do Sul, na ecorregião da Mata Atlântica do Alto Paraná, parte do bioma da Mata Atlântica.

Intra-specific pelage color variation in a South American small rodent species / Variação intraespecífica da cor da pelagem de uma espécie de pequeno roedor sul-americano

Abstract Intra-specific color variation is often underestimated by researchers, and among mammals, intra-specific differences in coloration are poorly documented for most species. The main goal of this study was to apply an objective color measurement methodology to the study of a specific problem: the detection, if any, of patterns of changes in the fur color of specimens of Akodon budini in relation to biological (i.e., sex) and environmental (i.e., season) variables. We hypothesize that coat color will be more homogeneous in males than in females and that coat color will be darker in winter than in summer, the latter being orange. We measured the pelage color on five points over the dorsal surface of 26 A. budini museum specimens using a spectroradiometer and a diffuse illumination cabin. We used Principal Component Analysis to describe the association between the color variables, sex and season, and each of the observations. We then used general linear models of Analysis of Variance to examine relationships between color data, season, and sex. The results clearly confirm the hypothesis related to seasonal coat color change but do not directly confirm the hypothesis related to changes in coat color in relation to sex, and we show the complexity of the studied pattern. In conclusion, undoubtedly, the studied variables should accordingly be considered when studying the coloration of specimens for characterization, identification and discrimination of different taxonomic units based on color.

Resumo Variação de cor intra-específica é muitas vezes subestimada pelos pesquisadores, e entre espécies de mamíferos, as diferenças intra-específicas na coloração são pouco conhecidas para a maioria das espécies. O principal objetivo deste estudo foi aplicar uma metodologia objetiva de medição de cor para o estudo de um problema específico: a detecção de padrões de mudanças na cor da pele de espécimes de Akodon budini em relação a variáveis biológicas (i.e., sexo) e ambientais (i.e., temporada), se houver. Nossa hipótese é que a cor da pelagem do sexo masculino será mais homogênea do que a de fêmeas e que a cor da pelagem do inverno vai ser mais escura do que a de verão, sendo esta última mais laranja. Medimos a cor da pelagem em cinco pontos sobre a superfície dorsal de 26 espécimes de museu de A. budini usando um espectroradiômetro e uma cabine de iluminação difusa. Usamos Análise de Componentes Principais para descrever a associação entre as variáveis de cor, sexo e temporada, e cada uma das observações. Em seguida, usamos modelos lineares gerais da Análise de Variância para verificar as relações entre os dados de cor, temporada, e sexo. Os resultados confirmam claramente a hipótese relacionada à mudança sazonal de cor da pelagem, mas não confirmam diretamente a hipótese relacionada com alterações na cor da pelagem em relação ao sexo, e vamos mostrar a complexidade do modelo estudado. Em conclusão, sem dúvida, as variáveis estudadas devem consequentemente ser tidas em conta quando se estuda a coloração de amostras para caracterização, identificação e discriminação de diferentes unidades taxonômicas com base na cor.

Musk gland seasonal development and musk secretion are regulated by the testis in muskrat (Ondatra zibethicus)

BACKGROUND: The muskrat is a seasonal breeder. Males secrete musk to attract females during the breeding season. The testosterone binding to the androgen receptor (AR) in musk glands of muskrat may play an important role conducting the musk secretion process. METHODS: The musk gland, testis and blood samples of musk rats are collected in both breeding and non-breeding seasons. Some part of the samples are kept in liquid nitrogen for transcriptome analysis and Western blotting test. Some part of the samples are kept in 70% alcohol for histology experiment, blood samples are kept at -20 °C for the serum testosterone measurement experiment. RESULTS: This study demonstrates that the quantity of secreted musk, the volume of the musk glands, the diameter of the gland cells and AR expression are all higher during the breeding season than at other times (p < 0.01). StAR, P450scc and 3ß-HSD expression in the Leydig cells of the testis were also higher during this season, as was serum testosterone. AR was also observed in the gland cells of two other musk-secreting animals, the musk deer and small Indian civet, in their musk glands. These results suggest that the testes and musk glands co-develop seasonally. CONCLUSION: The musk glands' seasonal development and musk secretion are regulated by the testes, and testosterone plays an important role in the seasonal development of musk glands.

First record of Pseudoryzomys simplex (Cricetidae, Sigmodontinae) in a flooded area of the Pantanal, Brazil / Primeiro registro de Pseudoryzomys simplex (Cricetidae, Sigmodontinae) em área alagada do Pantanal, Brasil

Abstract Pseudoryzomys simplex is a small to medium sized terrestrial rodent confined to lowland open areas with strong seasonal rainfall throughout the Chaco, Cerrado and Caatinga. Despite its extensive range, the species is difficult to trap. In this report we provide the first record of P. simplex in the Pantanal, where three specimens were collected in a pasture of exotic grass. The specimens are morpometrically similar to the population from Paraguay (Chaco). In this sense, our report shows how interesting a taxonomic review of the species would be to better understand the real significance of the geographic variation herein observed.

Resumo Pseudoryzomys simplex é um roedor terrestre de pequeno a médio porte que ocorre em áreas abertas de planícies com fortes precipitações sazonais ao longo dos Chaco, Cerrado e Caatinga. Apesar de sua extensa distribuição, a espécie é difícil de ser capturada. No presente estudo, fornecemos o primeiro registro de P. simplex no Pantanal, onde três espécimes foram coletados em uma pastagem de capim exótico. Os espécimes são morfometricamente semelhantes à da população do Paraguai (Chaco). Neste sentido, o nosso relatório mostra quão interessante seria uma revisão taxonômica das espécies para melhor compreender o significado real da variação geográfica aqui observada.

Ten years of a hantavirus disease emergency in the Federal District, Brazil

Abstract: INTRODUCTION: Hantavirus diseases are emerging human diseases caused by Hantavirus spp. of the Bunnyaviridae family. Hantavirus pulmonary syndrome (HPS) has been detected in the Federal District (DF) of Brazil since 2004. Among the 27 Brazilian Federal Units, DF has the highest fatality rate. More than 10 years have already passed since then, with confirmation of cases caused by the Araraquara and Paranoa species. The reservoir is Necromys lasiurus. METHODS: Local surveillance data of the confirmed cases were analyzed, including age, sex, month and year of occurrence, clinical symptoms, syndromes and outcomes, and probable transmission place (PTP). The cases were mainly confirmed by IgM detection with a capture enzyme immunoassay. The cases were classified as autochthonous if PTPs were in the DF area. RESULTS: From 2004 to 2013, in the DF, 126 cases of hantavirus were confirmed, and the cumulative incidence was 5.0 per 100,000 inhabitants. The occurrence of cases was predominantly from April to August. At least 75% of the cases were autochthonous. Acute respiratory failure was reported in 47.5% of cases, and the fatality rate was 40%. CONCLUSIONS: In the DF, the cumulative incidence of HPS was one of the highest worldwide. A seasonal pattern of hantavirus disease in the dry season is clear. There was a high frequency of severe clinical signals and symptoms as well as a high fatality rate. For the near future, visitors and inhabitants of DF rural areas, particularly male adults, should receive continuous education about hantavirus transmission and prevention.

A Microtus fortis protein, serum albumin, is a novel inhibitor of Schistosoma japonicum schistosomula

Schistosomiasis is an endemic parasite disease and praziquantel is the only drug currently in use to control this disease. Experimental and epidemiological evidence strongly suggests that Microtus fortis ( Mf ) is a naturally resistant vertebrate host of Schistosoma japonicum . In the present study, we found that Mf serum albumin ( Mf -albumin) and the conditioned medium of pcDNA3.1- Mf -albumin caused 46.2% and 38.7% schistosomula death rates in 96 h, respectively, which were significantly higher than that of the negative control (p < 0.05). We also found that mice injected with Mf -albumin had a 43.5% reduction in worm burden and a 48.1% reduction in liver eggs per gram (p < 0.05) in comparison to the control animals. To characterise the mechanisms involved in clearance, schistosomula were incubated with fluorescein isothiocyanate-labelled Mf -albumin and fluorescent enrichment effects were found in the gut lumen of schistosomula after 48 h of incubation. Next, digestive tract excretions from schistosomula were collected and the sensitivity of Mf -albumin to digestive tract excretions was evaluated. The results indicated that schistosomula digestive tract excretions showed indigestibility of Mf -albumin. The death of schistosomula could be partially attributed to the lack of digestion of Mf -albumin by digestive tract excretions during the development of the schistosomula stage. Therefore, these data indicate the potential of Mf -albumin as one of the major selective forces for schistosomiasis.

Noteworthy records of Ixodes schulzei (Acari: Ixodidae) on rodents from the State of Parana, southern Brazil / Relatos de Ixodes schulzei (Acari: Ixodidae) em roedores do estado do Paraná, sul do Brasil

Ixodes schulzei Aragão & Fonseca is an endemic tick to Brazil and has already been reported in the northern (State of Rondonia), southeastern (States of Minas Gerais, Rio de Janeiro and São Paulo) and southern (State of Santa Catarina) regions, always found in association with the water rat Nectomys squamipes (Brandt). This communication records the first occurrence of this tick species in the State of Parana, southern region of Brazil, and it constitutes its first report on Akodon montensis (Thomas) and Oryzomys russatus (Wagner) hosts.

Ixodes schulzei Aragão & Fonseca é um carrapato endêmico do Brasil e já foi relatado nas regiões Norte (estado de Rondônia), Sudeste (estados de Minas Gerais, Rio de Janeiro e São Paulo) e Sul (estado de Santa Catarina), tendo sido encontrado sempre em associação com o rato d'água Nectomys squamipes (Brandt). Esta comunicação registra a primeira ocorrência dessa espécie de carrapato no estado do Paraná, região Sul do Brasil e constitui o primeiro relato de Akodon montensis (Thomas) e Oryzomys russatus (Wagner) como hospedeiros.

Animal infections by vaccinia-like viruses in the state of Rio de Janeiro: an expanding disease / Infecções animais por vírus semelhantes ao vaccínia no estado do Rio de Janeiro: uma doença em expansão

In the present study we investigated the presence of infections by vaccinia-like viruses in dairy cattle from 12 counties in the state of Rio de Janeiro in the last 9 years. Clinical specimens were collected from adult animals with vesicular/pustular lesions mainly in the udder and teats, and from calves with lesions around the nose and mouth. A plaque reduction neutralization test (PRNT) was applied to search for antibodies to Orthopoxvirus; the vesicular/pustular fluids and scabs were examined by PCR, electron microscopy (EM) and by inoculation in VERO cells for virus isolation. Antibodies to Orthopoxvirus were detected in most cases. The PCR test indicated a high nucleotide homology among the isolates and the vaccinia viruses (VACV) used as controls. By EM, typical orthopoxvirus particles were observed in some specimens. The agents isolated in tissue culture were confirmed as vaccinia-like viruses by EM and PCR. The HA gene of the vaccinia-like Cantagalo/IOC virus isolated in our laboratory was sequenced and compared with other vaccinia-like isolates, showing high homology with the original Cantagalo strain, both strains isolated in 1999 from dairy cattle. Antibodies to Orthopoxvirus were detected in one wild rodent (genus Akodon sp.) collected in the northwestern region of the state, indicating the circulation of poxvirus in this area. Nonetheless, PCR applied to tissue samples collected from the wild rodents were negative. Vesicular/pustular lesions in people in close contact with animals have been also recorded. Thus, the vaccinia-like virus infections in cattle and humans in the state seem to be an expanding condition, resulting in economic losses to dairy herds and leading to transient incapacitating human disease. Therefore, a possible immunization of the dairy cattle in the state should be carefully evaluated.

Neste estudo avaliou-se a presença de infecções por vírus semelhantes ao vírus vaccínia (VACV) em gado leiteiro em 12 municípios no estado do Rio de Janeiro, ao longo dos últimos nove anos. Amostras clínicas foram coletadas de animais com vesículas, pústulas e crostas no úbere e tetas, e da região do nariz e da cavidade oral de bezerros. Um teste de neutralização viral por redução de placas foi desenvolvido para investigar a presença de anticorpos contra Orthopoxvirus. Os fluidos de vesículas / pústulas e as crostas foram testadas por PCR, microscopia eletrônica (ME) e por inoculação em células VERO para isolamento viral. Anticorpos contra Orthopoxvirus foram detectados na grande maioria dos animais. O teste de PCR demonstrou homologia entre os vírus isolados e amostras de vírus vaccínia usados como controles. Na ME, partículas típicas de Orthopoxvirus foram observadas em vários espécimes analisados. Os vírus isolados em cultivo celular foram confirmados como Orthopoxvirus por PCR e ME. O gene HA da amostra Cantagalo/IOC isolada em nosso laboratório foi seqüenciado e comparado com outras amostras semelhantes ao vaccínia, mostrando uma alta homologia com a amostra original Cantagalo, tendo sido as duas amostras isoladas em 1999 de gado leiteiro. Anticorpos para Orthopoxvirus foram detectados em um roedor silvestre do gênero Akodon sp. coletado na região noroeste do estado, sugerindo uma circulação de poxvírus na natureza. No entanto, os testes de PCR aplicados a tecidos de roedores silvestres foram negativos. Infecções vesiculares / pustulares em humanos que mantinham contato com os animais afetados também foram relatadas. Assim, infecções por amostras semelhantes ao vírus VACV em bovinos e em humanos parecem em expansão no estado, gerando perdas econômicas em animais e quadros de doença incapacitante temporária em pacientes humanos. Dessa forma, a possibilidade da imunização do gado leiteiro no estado deve ser devidamente avaliada.

Study of the social hierarchy and territoriality of Calomys callosus Rengger, 1830 (Rodentia: Cricetidae)

The genus Calomys comprises a lot of species distributed throughout South America. The species C. callosus Rengger, 1830 occur in Brazil, been often used in laboratory experiments. This work involved a study of aggressive behavior and dominance, which are aspects related to hierarchy and territoriality, among C. callosus males kept in a laboratory. The establishment of a hierarchy was observed, with the dominant animals controlling the space, food and water, while the remaining animals were confined to a restricted space. The intensity of aggression and variations in the number of attacks declined over time as a result of the formation of the hierarchy. No wounds were observed, probably due to the ritualistic nature of the attacks.

O genêro Calomys inclui várias espécies encontradas na América do Sul. A espécie C. callosus Rengger, 1830 ocorre no Brasil, sendo freqüentemente utilizada em experimentos de laboratório. Neste trabalho foram estudados, em machos mantidos em laboratório, o comportamento agressivo e a dominância, aspectos relacionados à hierarquia e territorialidade. Foi observado o estabelecimento de hierarquia, com os animais dominantes controlando o espaço, o alimento e a água, ficando os demais confinados em um espaço restrito. A intensidade das agressões e as variações no número de ataques diminuiram com o tempo, uma conseqüência da formação de hierarquia. Não foram observados ferimentos, devido provavelmente à ritualização dos ataques.

The relationship of sex and ectoparasite infestation in the water rat Scapteromys aquaticus (Rodentia: Cricetidae) in La Plata, Argentina

I studied the relationship between sex and infestation with ectoparasites in the water rat Scapteromys aquaticus from La Plata river marshland, Argentina. The Relative Density's Index (RDI) for males was 3.90% (females 3.60%). A total of 2653 ectoparasites were collected on 33 male hosts, and 1945 on 31 females. Ectoparasite specific richness (S) and diversity (H) were S = 14, H = 1.17 on males, and S = 10, H = 1.52 on females. The similarity between male and female rodents according to their ectoparasites was 75.00%. Although no ectoparasite species showed significant mean abundance (MA) differences between host sexes (p < 0.05), and only Laelaps manguinhosi prevalence was significantly higher on male hosts (N = 2.01, p < 0.05) in this study, there are reasons to think that the sex of the water rat affects ectoparasite burden and specific richness. This information has epidemiological potential because the closely related Scapteromys tumidus is involved in the transmission of Rickettsia coronii, which causes Marsella fever in humans.

Se estudió la interrelación entre el sexo de la rata de agua Scapteromys aquaticus y su infestación por ectoparásitos en la ribera del Río de la Plata, Argentina. El índice de densidad relativa de los machos fue 3.90 % y el de las hembras 3.60%. Se recolectó 2653 ectoparásitos de 33 machos y 1945 de 31 hembras. La riqueza (S) y diversidad específicas (H) de los ectoparásitos fueron S = 14, H = 1.17 en los machos y S = 10, H = 1.52 en las hembras. La similitud entre sexos fue del 75.00%. Si bien ningún ectoparásito en este estudio mostró diferencias significativas en su abundancia media entre los hospedadores de diferente sexo (p<0.05) y sólo la prevalencia de Laelaps manguinhosi fue significativamente mayor en los machos (N = 2.01, p<0.05), otros datos sugieren que sí existe un patrón de diferencias sexuales.

Hantavirus del Nuevo Mundo. Ecología y epidemiología de un virus emergente en Latinoamérica / The new-world hantaviruses. Ecology and epidemiology of an emerging virus in Latin America

The hantaviruses are a group of emerging rodent-borne pathogens (family Bunyaviridae; Genus Hantavirus) that are etiologic agents for hemorrhagic fever with renal syndrome (HFRS) in Europe and Asia and hantavirus cardiopulmonary syndrome (HCPS) in the Americas. HFRS is associated with rodents of the family Muridae, subfamilies Murinae and Arvicolinae; HPS is associated with rodents of the subfamily Sigmodontinae. Since the identification of HCPS in USA in 1993, a large number of cases of HPS and an increasing number of hantaviruses and rodent reservoir hosts have been identified in Central and South America. Epidemiologic studies have demonstrated important differences in frequency of infection with hantaviruses in both human and rodent host populations. Antibody prevalences in rodent and human populations may vary from less than 1% to more than 40%. Currently, more than 1500 cases of HCPS have been reported and more than 15 genetically distinct variants of hantaviruses, all associated with sigmodontine rodents, have been identified throughout the Americas. Several characteristics distinguish Latin American HCPS cases from the classical HCPS described for the first time in the USA. These include a variation in severity of disease from moderate and self-limiting to severe, the demonstration of person-to-person transmission, and a somewhat higher incidence of extrapulmonary clinical manifestations in the South American form of HCPS. Nevertheless, our understanding of hantaviruses in the Americas is still far from complete. The factors involved in the dynamics of these viruses in nature, their establishment and transmission within host populations and from hosts to humans, and the variable pathology of these viruses in humans are complex. It is likely that more hantaviruses will be described in the future, and much more data will be required in order to describe the diversity and evolution of this group of pathogens. Latin America, as the center of diversity for...

Los hantavirus son un grupo de patógenos emergentes (familia Bunyaviridae; género Hantavirus)identificados como agentes etiológicos de la Fiebre Hemorrágica con Síndrome Renal (FHSR) en Europa y Asia y el Síndrome Cardiopulmonar por Hantavirus (SCPH) en las Américas. La FHSR está relacionada con roedores de las subfamilias Murinae y Arvicolinae y el SCPH con roedores de las subfamiliasSigmodontinae y Arvicolinae. Desde la identificación del SCPH en los EE.UU. en 1993, muchos casos de SCPHy un número cada vez mayor de hantavirus y sus roedores reservorios han sido identificados en Centro y SudAmérica. Estudios epidemiológicos han demostrado diferencias notables en las seroprevalencias de anticuerposen humanos y roedores reservorios que oscilan entre el 1% y más del 40%. Hasta ahora han sido notificadosen toda América más de 1500 casos de SCPH y aproximadamente más de 15 variantes de hantavirus genéticay serológicamente distintos asociados a roedores sigmodontinos. Las formas clínicas leves-autolimitadas, moderadasy graves de la enfermedad, los antecedentes de transmisión persona a persona y una incidencia mayorde manifestaciones clínicas extrapulmonares que se diferencian de la enfermedad clásica descrita por primera vez en EE.UU., son aspectos importantes sobre la epidemiología de los hantavirus y el SCPH enLatinoamérica; sin embargo, la historia completa de los hantavirus está aún por escribirse, debido a la naturalezadinámica de estos virus y sus patologías, y a la complejidad de los factores que intervienen en su aparición, establecimiento y diseminación en poblaciones humanas y animales. Latinoamérica continúa representando laporción del continente con una oportunidad única y desafiante para el ...

Barreira placentária de Calomys callosus (Rodentia, Cricetidae) / Placental barrier of Calomys callosus (Rodentia, Cricetidae)

O presente trabalho objetivou caracterizar ultra-estruturalmente a barreira placentária de Calomys callosus. Calomys callosus é um roedor de pequeno tamanho encontrado no cerrado brasileiro, principalmente na região do estado de Goiás. Utilizou-se amostras de placentas entre 15º a 20º dias de gestação. As amostras foram fixadas em glutaraldeído 2,5% em tampão fosfato 0,1 M pH 7,2 e processadas para inclusão em Epon e análise em microscopia eletrônica de transmissão. A placenta de Calomys callosus é composta pelas regiões de espongiotrofoblasto, células troboblástica gigantes e labirinto. No labirinto o sangue materno irriga células trofoblásticas ao passo que o sangue fetal está contido em vasos fetais presentes no mesênquima das trabéculas trofoblásticas. Separando o sangue materno do sangue fetal encontram-se 3 camadas de células trofoblásticas (camadas I, II e III), sendo esta placenta considerada hemotricorial, além do endotélio fetal. Estas camadas constituem a barreira placentária e, a medida que progride a gestação, tornam-se progressivamente mais delgadas.

Intestinal fibrovascular nodules caused by Schistosoma mansoni infection in Calomys callosus Rengger, 1830 (Rodentia: Cricetidae): a model of concomitant fibrosis and angiogenesis

Human schistosomiasis develops extensive and dense fibrosis in portal space, together with congested new blood vessels. This study demonstrates that Calomys callosus infected with Schistosoma mansoni also develops fibrovascular lesions, which are found in intestinal subserosa. Animals were percutaneously infected with 70 cercariae and necropsied at 42, 45, 55, 80, 90 and 160 days after infection. Intestinal sections were stained for brightfield, polarization microscopy, confocal laser scanning, transmission and scanning electron microscopies. Immunohistological analysis was also performed and some nodules were aseptically collected for cell culture. Numerous intestinal nodules, appearing from 55 up to 160 days after infection, were localized at the interface between external muscular layer and intestinal serosa, consisting of fibrovascular tissue forming a shell about central granuloma(s). Intranodular new vessels were derived from the vasculature of the external vascular layer and were positive for laminin, chondroitin-sulfate, smooth muscle alpha-actin and FVIII-RA. Fibroblastic cells and extracellular matrix components (collagens I, III and VI, fibronectin and tenascin) comprised the stroma. Intermixed with the fibroblasts and vessels there were variable number of eosinophils, macrophages and haemorrhagic foci. In conclusion, the nodules constitute an excellent and accessible model to study fibrogenesis and angiogenesis, dependent on S. mansoni eggs. The fibrogenic activity is fibroblastic and not myofibroblastic-dependent. The angiogenesis is so prominent that causes haemorrhagic ascites

Acquired and congenital ocular toxoplasmosis experimentally induced in Calomys callosus (Rodentia, Cricetidae)

An experimental model for acquired and congenital ocular toxoplasmosis as well as a model to induce experimental autoimunne uveitis (EAU) was investigated in Calomys callosus. Toxoplasma gondii, ME-49 strain, was used to infect males and pregnant and not pregnant-females while S-antigen, a major glycoprotein of the retinal photoreceptor cell, was used to induce EAU. The ocular lesions elicited by T. gondii were characterized by the presence of cysts, free tachyzoites and inflammatory cells in the retina or related tissues. In the congenital form, 40 per cent of the fetus presented ocular lesions, i.e., presence of cysts in the retina, vitreous, and extra-retinal tissues. In the acquired form, 75 per cent of the females and 50 per cent of the males presented unilateral ocular cysts both at 21 and 47 days post-infection. It was also demonstrated that S-antigen was not uveitogenic in the C. callosus model. No lesion was observed in the animals exclusively immunized with this retinal component, even when jacalin was used as addicional adjuvant for polyclonal response to the retinal antigen. It can be concluded that C. callosus may constitue in a promising model for study both acquired and congenital ocular toxoplasmosis, particularly when it is important to make sure that a non autoimmune process is involved in the genesis of the ocular infection.

Effects of schistosomal mansoni infection on Calomys callosus coelom-associated lymphomyeloid tissue (milky spots)

Calomys callosus Rengger, 1830 (Rodentia: Cricetidae) is a mouse-like South American wild rodent, which is permissive to Schistosoma mansoni infection. In this paper we studied the effect of schistosomal infection in C. callosus mesenteric and omental milky spots (MS), subsidiary foci of coelom-associated lymphomyeloid tissue (CALT), during the acute, transitional (acute to chronic), and chronic phases of the infection. MS were morphologically analyzed by historical methods, using brightfield and confocal laser scanning microscopies. The MS of infected animals were mainly of lymphomyelocytic (42 to 90 days) and lymphoplasmacytic (160 days of infection) types and showed frequent presence of lymphoid follicles with germinal centers, plasmacytogenesis and plasmacytosis, mastocytosis, megakaryopoiesis, erythropoiesis and less pronounced eosinopoiesis. These results indicate that MS are a preferencial site of germinal-center-dependent and independent plasmacytogenesis, and a bone narrow-like organ, committed with various cellular lineages. The consequence of a C. callosus MS reactivity for schistosomal infection is still unknown and is under investigation.