Prevalence of hepatitis A virus infection in Afro-Brazilian isolated communities in Central Brazil

To investigate hepatitis A virus (HAV) infection rates among isolated African-descendant communities in Central Brazil, 947 subjects were interviewed about demographic characteristics in all 12 isolated Afro-descendant communities existing in the state of Mato Grosso do Sul, Central Brazil, between March 2002 and November 2003. Blood samples were collected and sera were tested for HAV antibodies (total and IgM anti-HAV) by enzyme-linked immunosorbent assay. The overall prevalence of HAV infection was 75.6% (95% CI: 72.7-78.3), ranging from 55.4 to 97.3%, depending on the communities studied. The prevalence of anti-HAV increased significantly with age, from 13.8% in the age 0-5 age group to 96.6% in those older than 40 years. The findings point out an intermediate endemicity of HAV infection in some Afro-Brazilian isolated communities in Central Brazil. In addition, the high proportion of susceptible young subjects could be target of future HAV vaccination programs.     

A little bit is better than nothing: the incomplete parthenogenesis of salamanders,frogs and fish

A re-examination of the mitochondrial genomes of unisexual salamander lineages, published in BMC Evolutionary Biology, shows them to be the oldest unisexual vertebrates known, having been around for 5 million years. This presents a challenge to the prediction that lack of genetic recombination is a fast track to extinction.     

Childbirth as ritual in Brazil: young mothers' experiences

The article examines childbirth in a public hospital in Salvador, Brazil, as a multidimensional, embodied process and as a rite of passage. The birth narratives of young, poor, black mothers are seen through ethnography of the obstetric centre, run by white, middle-class obstetricians. The article follows the biosocial process of birth, tracing the development and mutation of loneliness, fear, and pain into motherlove. This subjective journey is generated within the social interactions constituting the physiological birth events. Primiparous women are shown to construct the birth as a rite of passage into legitimate motherhood, in the face of a hegemonic symbolic frame that stigmatizes youthful motherhood and delegitimizes reproduction amongst young, black, low-income women. Hospital childbirth's most powerful social effect is the constitution and consecration of a race/class divide.     

A model for the evolutionary diversification of religions

We address the problem of cultural diversification by studying selection on cultural ideas that colonize human hosts and using diversification of religions as a conceptual example. In analogy to studying the evolution of pathogens or symbionts colonizing animal hosts, we use models for host-pathogen dynamics known from theoretical epidemiology. In these models, religious content colonizes individual humans. Rates of transmission of ideas between humans, i.e., transmission of cultural content, and rates of loss of ideas (loss of belief) are determined by the phenotype of the cultural content, and by interactions between hosts carrying different ideas. In particular, based on the notion that cultural non-conformism can be negative frequency-dependent (for example, religion can lead to oppression of lower classes and emergence of non-conformism and dissent once a religious belief has reached dominance), we assume that the rate of loss of belief increases as the number of humans colonized by a particular religious phenotype increases. This generates frequency-dependent selection on cultural content, and we use evolutionary theory to show that this frequency dependence can lead to the emergence of coexisting clusters of different cultural types. The different clusters correspond to different cultural traditions, and hence our model describes the emergence of distinct descendant cultures from a single ancestral culture in the absence of any geographical isolation.     

Heterogeneity of the Y chromosome in Afro-Brazilian populations

Sixteen biallelic markers (SRY10831a, SRY10831b, SRY4064, SRY2627, 92R7, P2, P3, M34, M9, M3, M2, YAP, M60, M89, M213, M216) located in the nonrecombinant region of the Y chromosome were analyzed in 209 individuals belonging to six Brazilian populations: four Afro-Brazilian populations, one population of white European descendants, and one population of Japanese descendants. The results showed that most of the Y chromosomes of the Afro-Brazilians were from sub-Saharan Africa and that the proportion of Y chromosomes of European origin was greater than that of Y chromosomes of Amerindian origin. No typical African or Amerindian haplogroup was detected among Japanese individuals, and only one white individual showed a typical African haplogroup. Haplogroup P-92R7, which is highly frequent in the Portuguese and Italian populations, was the most frequent among whites (54%), and haplogroup K-M9, which shows wide geographic distribution and is absent in Africa, was the most frequent among Japanese individuals (65.6%). The two semi-isolated Afro-Brazilian populations showed the highest and the lowest genetic diversity, respectively. These differences probably reflect the effect of greater or smaller gene flow between a small isolated group and other populations. These findings show that the process of admixture does not occur homogeneously, with a tendency toward preferential marriages within the ethnic group and a clear direction in unions between European men and Amerindian or African women in the past. The results agree with historical and social data about the formation of the Brazilian population and reveal some of the factors that contribute to its heterogeneity.     

The Faith of Sacrifice: Leadership Trade-Offs in an Afro-Brazilian Religion

Despite secular trends in some countries, prestige-based authority in the form of religious leadership remains hugely influential in the everyday lives of millions of people around the world. Here, the costs and benefits of religious leadership are explored in an urban setting in northeastern Brazil. An economic game, within-group cooperation questionnaires, and social network analyses were carried out among adherents of an Afro-Brazilian religion. Results reveal that leaders display high levels of religious commitment and disproportionally provide cooperative services to group members. On the other hand, initiates cooperate less than leaders but do not differ in levels of received cooperation or social cohesion measures. This may indicate some level of exploitation or free-riding. Demographic and group variables also appear to play an important role in the degree of social cohesion a group achieves. These findings are discussed in the context of non-Western urban settings where religious leadership may represent both an alternative to social advancement and a crucial source of material aid, social support, and a strong sense of community.     

A comparative approach to the French medical missions in Brazil and in sub-Saharan Africa before the Second World War

Franco-Brazilian cooperation in the field of microbiology and tropical diseases dates back to the onset of those disciplines. Physicians were sent over by France, namely Marchoux, Simond and Salimbeni from 1901 to 1905 to study yellow fever, and Emile Brumpt from 1913 to 1914 to teach parasitology. These missions brought in some important results. After confirming that the yellow fever agent was a filterable virus and that Stegomya (Aedes) its only vector, Simond and Marchoux clarified the biology of the mosquito and showed that sexual transmission of the virus could occur. They also set up different measures for the control of yellow fever outbreaks which Oswaldo Cruz was inspired by for his campaign against yellow fever. Emile Brumpt implemented the teaching of parasitology at the Faculty of Medicine in S?o Paulo and contributed to human American trypanosomiasis by defining the transmission of the disease and the cycle of the parasite responsible for it. He also developed the technique known as xenodiagnosis. Simond and Marchoux's works on yellow fever found an immediate application in French colonies, particularly in sub-Saharan Africa. However, the fight against large African endemics such as sleeping sickness, the other human trypanosomiases, could not have been carried out successfully without the contribution of mobile teams following Eugène Jamot's initiative in addition to the permanent centres which characterized the French colonial system.     

Folk conceptualizations of racism and antiracism in Brazil and South Africa

Abstract

Folk conceptualizations of racism can be defined as ordinary people's understandings of the sources and persistence of racism. They function as equalization strategies – by denying the legitimacy of racism – and guide beliefs regarding antiracism strategies. I explore folk explanations of racism among black professionals in Brazil and South Africa by drawing on sixty interviews with members of these groups. In Brazil, racism is understood as an historical lingering, a product of ignorance, which will disappear with time and education. In South Africa, racism is viewed as more resilient, as a part of human nature and as a consequence of the competition for resources. These explanations of racism are closely related to the antiracism narratives that are salient in these two contexts: while Brazilian respondents affirm their belief in racial mixture and moral education, South African respondents are more uncertain about the possibilities of weaker racial boundaries in their country, relying on institutional constraints as their main antiracism strategy.     

New approaches for field studies of mammals: experiences with marine mammals

The constraints imposed by studying a mammal in an aquatic environment and by the nerd to use benign methods have made it necessary to develop novel approaches in order to investigate the biology of marine mammals. The approaches have been made possible by recent technological advances and by the willingness of granting agencies to fund expensive, high–risk projects in marine science.
We review new trchniques which have been developed for estimating the population size of marine mammals, for investigating the relationsip between individuals and populations, for studying the behaviour and energetics of animals in the open sea, and for the management of small and endangered populations. We also indicate how these techniques may be applied to a variety of terrestrial mammals.