Arquivo da tag: Saúde pública

The Future Will Be Swarming With Rats (Motherboard)

Written by BRIAN MERCHANT, SENIOR EDITOR

July 29, 2014 // 02:00 PM CET

That cockroaches will inherit our despoiled earth is just a tired misconception. The real champions will be disease-carrying rats.

Even though cockroaches seem to be of inexhaustible supply, their invertebrate ilk are actually suffering a fairly rapid decline—and the rodents are rising up. In a recent and widely-discussed study in Science, researchers examined a process called defaunation—remember that term, it’s likely to prove as vital as ‘Arctic ice melt’ or ‘habitat loss’ to understanding our planet’s ecological collapse—that describes how the majority of the world’s animals are vanishing at a rapid pace.

Led by Rodolfo Dirzo, a professor of biology at Stanford University, a team of scientists documented the rate that fauna are going extinct in the modern era. Since the year 1500 AD, at least 320 vertebrate species have been extinguished, primarily due to human activity. Those that remain have seen their total populations decline by 25 percent. Even more striking is the decline of insects: In the past 35 years alone, the scientists found that the number of invertebrates have plummeted 45 percent. The researchers cite the drops as further evidence that we are bearing witness to the unfurling of the Anthropocene Extinction event—the planet’s sixth great mass extinction.

So who wins, besides humans, when the bees and the tigers and the bears lose? Rats.

“Where human density is high, you get high rates of defaunation, high incidence of rodents, and thus high levels of pathogens, which increases the risks of disease transmission,” Dirzo said in a statement upon the study’s publication. “Who would have thought that just defaunation would have all these dramatic consequences? But it can be a vicious circle.”

Hilary Young, one of the study’s authors, has conducted previous research examining how rodents thrived after a large species went extinct.

RATS COULD GROW LARGER THAN SHEEP

“What we found was that these areas quickly experienced massive increases of rodents,” Young told The Current. “All the grass and shrubs normally eaten by this megafauna was, instead, available for rodents—both as food and as shelter. Consequently, the number of rodents doubled—and so did the abundance of the disease-carrying ectoparasites that they harbored.”

Twice the rats. And twice the ectoparasites. A 2013 study in the International Journal of Current Microbiology and Applied Sciences examined how parasite-carrying rats are instrumental in transporting disease: “Rodents together with arthropod ectoparasites can play an important role in the distribution of the arboviruses, streptococcal infections, choriomeningitis, plague, tularemia, leptospirosis, spirochaetosis etc.,” the authors wrote.

“Ectoparasites include insects and acarnies (fleas and mites),” the 2013 study continued, “some of them are permanent like lice, while most of the mature ticks and fleas are temporary parasites. Rats are known to harbor four groups of arthropod ectoparasites: fleas, ticks, mites and lice… Some of the ectoparasites can biologically or mechanically transfer infectious agents to the human or animals and results in the spread of infection.”

In other words, rats carry a lot of parasites, which carry a lot of diseases. Here, according to the Centers for Disease Control, is a quick list of the diseases rats are currently responsible for spreading in the United States:

  • Hantavirus Pulmonary Syndrome
  • Hemorrhagic Fever with Renal Syndrome
  • Lassa Fever
  • Leptospirosis
  • Lymphocytic Chorio-meningitis (LCM)
  • Omsk Hemorrhagic Fever
  • Plague
  • Rat-Bite Fever
  • Salmonellosis
  • South American Arenaviruses (Argentine hemorrhagic fever, Bolivian hemorrhagic fever, Sabiá-associated hemorrhagic fever, Venezuelan hemorrhagic fever)
  • Tularemia

It’s an ugly list. And in light of their impending dominance, it’s worth remembering that rats played a key role in helping spread the bubonic plague during the Black Death. Crammed, unhygienic living conditions helped it become such a devastating killer, but it was an ectoparasite—a flea—that brought the plague.

“The bubonic plague, a disease still present in some areas of the world, is now known to have spread via fleas living on rats,” Mark Ormrod, a professor of history at the University of York, wrote for the BBC.

Our hygiene and health-care are much improved from Medieval times, but we are headed towards a future marked by shared, maybe cramped, living spaces: More than half the world’s population currently lives in cities, billions are slated to join them, and so, the megacities are growing. More urban living, paired with more rats, could beget similar, if not as deadly, health woes.

And Dirzo and his crew aren’t the only ones who worry about the rise of the rats. In fact, just earlier this year, another group of scientists determined that rodents would be the species most likely to outlast all others.

Dr. Jan Zalasiewicz, a geologist at the University of Leicester, believes that rats are the animal best suited to repopulate the world in the event of a mass extinction.

“[Rats] are now on many, if not most, islands around the world,” he explained, “and once there, have proved extraordinarily hard to eradicate. They’re often there for good, essentially. Once there, they have out-competed many native species and at times have driven them to extinction. As a result, ecospace is being emptied—and rats are in a good position to re-fill a significant chunk of it, in the mid to far geological future.”

For many of us, that future is exceedingly easy to imagine. By some counts, in New York, there are twice as many rats as human residents. They are a scourge in other cities, too, of course.

As humans continue to knock out the larger fauna, and the number of rats “double” to fill the void, we can, theoretically, look forward to seeing more of all of the above. And even if you’re not concerned with the health implications, there’s the simple fact that we’re hacking away at our immense, spectacular biodiversity, and trading it in for a deeply unpleasant, rat-centric monotony.

Beyond defaunation, there’s evidence that climate change is improving conditions for rats in general in many regions, too. It’s also probably worth adding at this point that warmer temperatures are causing some rat species to grow larger, too, thus adding another potential population booster. Zalasiewicz, for his part, imagines that once its competition is scarce, rats could become larger than sheep.

So that, then, is a foreboding slice of the Anthropocene: Giant, parasite-and-disease-carrying rats, multiplying in droves while everything else goes extinct.

 

 

Exposing Monsanto: Herbicide Linked to Birth Defects – the Vitamin A Connection (Truthout)

Monday, 28 July 2014 09:27

By Jeff Ritterman, M.D., Truthout | Op-Ed

Monsanto’s herbicide Roundup, with glyphosate as the primary ingredient, has recently been linked to a fatal kidney disease epidemic ravaging parts of Central America, India and Sri Lanka. A leading theory hypothesizes that complexes of glyphosate and heavy metals poison the kidney tubules. El Salvador and Sri Lankahave adopted the precautionary principle and taken action to ban the herbicide. In the United States, glyphosate is coming up for review by the Environmental Protection Agency (EPA) in late 2014. Monsanto claims a low risk to human health, but the research is showing something very different. Will these health concerns be enough for the EPA to put restrictions on the herbicide – or to ban it altogether?

Monsanto’s Claims of Safety

Thus far, Monsanto has been successful in portraying Roundup as a safe and effective herbicide. The Monsanto website claims:

Glyphosate binds tightly to most types of soil so it is not available for uptake by roots of nearby plants. It works by disrupting a plant enzyme involved in the production of amino acids that are essential to plant growth. The enzyme, EPSP synthase, is not present in humans or animals, contributing to the low risk to human health from the use of glyphosate according to label directions.

Public Kept in the Dark

Contrary to the company’s claims of safety, a virtual avalanche of scientific studies on animals, including some funded by Monsanto itself, show alarming incidences of fetal deaths and birth defects. The record also shows that Monsanto has known since the 1980s that glyphosate in high doses causes malformations in experimental animals. Since 1993, the company has been aware that even middle and low doses can cause these malformations. These malformations include absent kidneys and lungs, enlarged hearts, extra ribs, and missing and abnormally formed bones of the limbs, ribs, sternum, spine and skull.

These startling revelations can be found in the report Roundup and Birth Defects: Is the Public Being Kept in the Dark? The document is authored by eight experts from the fields of molecular genetics, agro-ecology, toxico-pathology, scientific ethics, ecological agriculture, plant genetics, public health and cell biology. This report, written primarily for a European readership, is highly critical of the biotech industry and of the European Union’s failure to evaluate glyphosate based on the science rather than on political concerns. It calls for an immediate withdrawal of Roundup and glyphosate from the European Union until a thorough scientific evaluation is done on the herbicide. From the report:

The public has been kept in the dark by industry and regulators about the ability of glyphosate and Roundup to cause malformations. In addition, the work of independent scientists who have drawn attention to the herbicide’s teratogenic effects has been ignored, denigrated or dismissed. These actions on the part of industry and regulators have endangered public health. (Authors note: Ateratogen is any agent that can disturb the development of an embryo or a fetus. The term stems from the Greek teras, meaning monster).

Monsanto’s Safety Claim Misleads

How is it possible that there are so many adverse health impacts in the test animals, if, as Monsanto claims, “the enzyme, EPSP synthase, is not present in humans or animals”?

The reason is simple. Roundup attacks other enzyme systems, which are indeed present in the animal kingdom.

We owe this knowledge to a group of scientists from Argentina who became concerned about human birth defects in areas of their country where Roundup was being sprayed from airplanes as part of genetically modified (GM) soy production. They decided to do laboratory research to explore whether Roundup would produce similar developmental abnormalities in test animals. Experimenting with frog and chicken embryos, they found that those embryos exposed to the herbicide developedsignificant malformations, including neural defects and craniofacial malformations similar to the birth defects seen in humans.

Not only did this group of scientists demonstrate that Roundup causes birth defects in the animals tested, but they also were able to demonstrate how Roundup caused the fetal abnormalities. The herbicide increased the activity of the Vitamin A (retinoic acid) “signaling pathway.” It’s called a signaling pathway because it turns genes on and off. Roundup causes an abnormal increase in activity of this pathway, which turns off certain genes. Unfortunately, those very genes are needed for normal embryological development. When the Roundup turns off those genes, birth defects result.

This signaling pathway is shared by virtually all vertebrates, including amphibians, birds and mammals. Thus, it seems quite likely that the birth defects seen in frogs, chickens, rats, rabbits and humans all occur because Roundup attacks this pathway. It also seems likely that if we continue to allow glyphosate to accumulate in the environment, we can expect vertebrates of many types to suffer increasing rates of birth defects. This, of course, includes humans.

Roundup and Birth Defects: the Story From Latin America

The Argentinian researchers were motivated by humanitarian concerns. They were aware of the many worrisome reports of increases in birth defects in Argentina and in other parts of Latin America attributed to aerial glyphosate spraying.

A frightening example is a study of birth defects in Argentina, which found that Cordoba, an area of intensive planting of GM soy and heavy glyphosate use, had a higher incidence of spina bifida (spinal cord protrusion in the lower back), microtia(abnormal ear), cleft lip and palate, polycystic kidney, postaxial polydactyly (extra fingers or toes) and Down’s Syndrome than other regions. Many of these defects are of the type associated with disturbances in the Vitamin A signaling system.

Chaco, Argentina is also a region of intensive GM soy production and heavy glyphosate use. In the last decade, coincident with expansion of GM soy production,birth defects have increased threefold and cancer rates have increased fourfold. A court in the adjacent province of Santa Fe, a major GM soy-producing region, banned the spraying of glyphosate and other agrochemicals in populated areas because of concerns about “severe damage to the environment and to the health and quality of life of the residents.”

Itapua, Paraguay is another GM soy dominated area. Here, residents have suffered a similar fate. Women exposed to glyphosate during pregnancy have a high incidence of fetal deformities similar to those seen in Argentina. These deformities, once again, can be explained by glyphosate’s ability to interfere with the Vitamin A signaling pathway.

Rounding Up the Science

Glyphosate has been conclusively proven to cause birth defects in frogs, chickens, rats, rabbits, and also in humans. Monsanto’s claim that Roundup is safe because it kills weeds by attacking one specific enzyme system not found in animals is misleading. Monsanto has a very large investment in maintaining this illusion. Half of Monsanto’s revenue comes from the sale of Roundup and Roundup Ready seeds.

Roundup attacks vital enzyme systems found in animals, including in humans. It is now clear that interference by Roundup with one of these enzyme systems, the Vitamin A signaling system, can result in severe birth defects. This system is shared by most vertebrates, making Roundup capable of inducing devastating birth defects in a wide variety of amphibians, birds and mammals, and possibly reptiles and fish as well. Allowing glyphosate to continue to build up in the environment will likely cause increased rates of birth defects in all vertebrates exposed, including humans. Exposure, of course, includes the digestion of exposed plants and animals.

Policy Recommendation

The science is clear. There is only one rational response. No family should have to tolerate the risk of significant birth defects – in the United States, or in any part of the world. Roundup and other glyphosate formulations should be banned. Thus far, the voices of public health advocates in this country have been drowned out by those promoting biotechnology and its profits, regardless of the health consequences. We can’t let this continue. Our health, the health of our children and the health of our environment must come first. It is the responsibility of our governmental institutions to protect humanity, not corporate profit.

It’s long past time for us to heed Rachel Carson’s warning from Silent Spring:

If we are going to live so intimately with these chemicals – eating and drinking them, taking them into the very marrow of our bones – we had better know something about their nature and their power.

Pass this on. Raise your voice.

Agora manteiga faz bem e carne faz mal? (Jornal da Ciência)

JC e-mail 4973, de 16 de junho de 2014

Artigo de Luís Maurício Trambaioli para o Jornal da Ciência

Está sendo amplamente divulgado na mídia um recente estudo em que os pesquisadores de Harvard, a partir de questionário de perguntas feito em 1991 a enfermeiras, inferiu que mulheres teriam 22 % de risco relativo aumentado de câncer de mama quando consumindo uma porção a mais de carne vermelha que mulheres que consomem menos.

Entretanto, risco relativo não é risco absoluto, o qual pode ser calculado pelos dados originais. A chance de desenvolver a doença seria vista em 1 em cada 100.000 mulheres, e não em 22 em cada 100 mulheres como tem sido noticiado pela falsa impressão que o ‘risco relativo’ nos dá. Mais, esta incidência é exatamente em grupos de mulheres que mais fumam.

É importante cuidado na forma que se divulga as notícias de estudos epidemiológicos e feitos por apenas um grupo. Melhor seria obter um parecer de especialistas na área e ainda preferencialmente resultados advindos de mais estudos obtidos por outros pesquisadores, evitando assim bias e viés na ciência. Sob risco de acontecer acusações levianas como ocorrido na década de 80 que levou a demonizar a gordura saturada há exatos 30 anos sem evidências científicas que suportassem tal idéia, o que direcionou a humanidade ao desespero de consumo de alimentos sem gordura e compensando com a ingestão de mais “carboidratos complexos” (amido) e baixos em micronutrientes. E o resultado foi a epidemia de diabetes e obesidade (chamado no exterior de diabesity), doenças cardiovasculares, câncer, dentre outras.

E agora, o que cortar do bacon: a gordura ou a carne ?

Luís Maurício Trambaioli é professor associado da Faculdade de Farmácia da UFRJ e pesquisador associado do INMETRO

Referências:

BMJ – “Dietary protein sources in early adulthood and breast cancer incidence: prospective cohort study” – http://dx.doi.org/10.1136/bmj.g3437

Resposta ao estudo: http://www.bmj.com/content/348/bmj.g3437?tab=responses

Time Magazine, 26/03/1984 – And Now the Bad News –
http://content.time.com/time/specials/2007/article/0,28804,1704183_1704257_1704499,00.html

Time Magazine, 23/06/2014 – Ending the War on Fat – http://time.com/2863227/ending-the-war-on-fat/
http://oglobo.globo.com/sociedade/saude/carne-vermelha-pode-aumentar-risco-de-cancer-de-mama-diz-estudo-de-harvard-12803653

Batalha contra nova pandemia de câncer no Sul (IPS) 

17/4/2014 – 10h49

por Kanya D’Almeida, da IPS

paciente Batalha contra nova pandemia de câncer no Sul

Nações Unidas, 17/4/2014 – Poucos no mundo podem alardear que o câncer não os tocou. Neste momento, milhões enfrentam uma batalha pessoal contra a doença e muitos mais estão sentados juntos a seres queridos que lutam por sua vida, visitando amigos que se recuperam de uma quimioterapia ou averiguando sobre os últimos tratamentos para seus familiares. O prognóstico da organização líder em pesquisa sobre câncer não indica melhorias. O Informe Mundial do Câncer 2014 diz que nos próximos 20 anos se espera que os novos casos aumentem 70%, chegando a 25 milhões em 2025.

Produzido a cada cinco anos pela Agência Internacional para a Pesquisa sobre o Câncer (Iarc), da Organização Mundial da Saúde, o informe de 632 páginas aponta que os novos casos passaram de 12,7 milhões em 2008 para 14,1 milhões em 2012. Neste último ano, o mundo experimentou o recorde de 8,2 milhões de mortes por câncer. Os países em desenvolvimento estão entre a cruz e a espada. Por um lado, seguem sofrendo uma grande presença de tipos de câncer associados a infecções, como o de colo uterino, estômago e fígado, que são relacionados à pobreza e à falta de água potável, vacinas, centros de detecção precoce e opções adequadas de tratamento.

Por outro lado, os tumores relacionados com estilos de vida opulentos, como o de pulmão, mama e intestino grosso – pelo elevado consumo de tabaco, álcool e alimentos pesados – também estão dizimando as fileiras crescentes das classes médias desses países.

A África, por exemplo, experimenta uma “alta alarmante” do tabagismo, e a previsão é que a quantidade de adultos fumantes passe de “77 milhões para 572 milhões até 2100, se não forem aplicadas novas políticas”, afirma a Sociedade Norte-Americana do Câncer. O sul-africano Evan Blecher, diretor do programa internacional de pesquisa sobre controle do tabaco dessa entidade, atribui esse aumento a múltiplos fatores. Um dos principais é o crescimento econômico.

“As economias africanas estão crescendo mais rapidamente e de forma mais sustentada do que nos últimos 50 anos”, afirmou Blecher à IPS, da Cidade do Cabo, sua cidade natal. “O crescimento econômico impulsiona o consumo de tabaco porque há mais dinheiro. Alguns dos países onde vemos maior aumento do tabagismo são Angola, República Democrática do Congo, Etiópia, Madagascar, Moçambique, Senegal e Nigéria, que são os de maior crescimento econômico da África e do mundo”, acrescentou.

Esta dupla carga, de tumores da pobreza e da opulência, paira sobre sistemas de saúde que já estão sob pressão. A Agência Internacional de Energia Atômica (AIEA) informa que os países de renda média e baixa, onde residem 85% da população mundial, possuem apenas 4.400 máquinas de megavoltagem, o que representa menos de 35% das instalações mundiais de radioterapia. A AIEA também afirma que 23 países com mais de um milhão de habitantes cada um, a maioria na África, não têm um só aparelho de radioterapia.

R. Sankaranarayanan, consultor especial da Iarc, pontuou à IPS que a brecha oncológica não separa apenas as nações em diferentes graus de desenvolvimento, mas as populações dentro delas. “A enorme disparidade de sobrevivência de câncer de mama entre as zonas rurais e urbanas de China, Índia e Tailândia, ou entre as populações negras e brancas dos Estados Unidos, é um bom exemplo”, ressaltou. Pesquisadores e médicos dos Estados Unidos dizem que há uma diferença de 8,8% nas taxas de mortalidade por câncer de mama das mulheres negras para as brancas.

Como a obesidade é um grave problema para as comunidades afro-norte-americanas (afeta 50% dos adultos negros e 35% dos brancos), não surpreende que elas tenham maior incidência de câncer colo-retal, associado ao consumo excessivo de alimentos processados e pouco saudáveis.

Na Índia, onde foram registrados mais de um milhão de novos casos em 2012 e quase um milhão de mortes por alguma forma de câncer, a grande diversidade de estilos de vida se mostra como o fator decisivo da brecha oncológica. Por exemplo, a maior incidência de câncer se registrou no Estado de Mizorán, uma das regiões de maior crescimento econômico, enquanto a menor ocorreu em Barshi, distrito rural do Estado de Maharashtra, onde boa parte da população se dedica à atividade agrícola.

Silvana Luciani, assessora em prevenção e controle do câncer da Organização Pan-Americana da Saúde, observou que as disparidades dos serviços de saúde dentro da região também resultam em taxas de mortalidade desequilibradas. “Na América Central a mortalidade por câncer de colo uterino é de 15 ou 18 mortes por cem mil pessoas, enquanto na América do Norte é de duas por cem mil”, detalhou à IPS. “Isso se deve a programas de detecção como o exame papanicolau que são realizados há muito tempo na América do Norte e têm uma qualidade muito maior do que na América Central, onde os serviços de saúde estão fragmentados”, acrescentou.

Sankaranarayanan destacou que países como Coreia do Sul, Turquia, Malásia, Índia, Gana, Marrocos, Brasil, Chile, Colômbia, Costa Rica e México “estão adotando sistemas de saúde de atenção universal ou seguros nacionais de saúde dirigidos às populações mais pobres”. Mas “as populações cada vez mais envelhecidas e o surgimento de tecnologias oncológicas muito caras aumentam as pressões sobre esses serviços”, enfatizou.

Uma barreira ao desenvolvimento

O câncer de pulmão encabeça a lista de diagnósticos, com 1,8 milhão, ou quase 13% do total mundial. Em seguida vem o câncer de mama, com 1,7 milhão, enquanto o que afeta o intestino grosso representa 9,7%.

O mais mortal continua sendo o de pulmão, que mata 1,6 milhão de pessoas por ano, enquanto outras 800 mil falecem por câncer de fígado e 700 mil por câncer de estômago. Esta mortandade é acompanhada de custos astronômicos dos serviços de saúde, que em 2010 chegaram a US$ 1,6 trilhão.

A incidência cresce em países de renda média e baixa que não têm nem a experiência nem os recursos financeiros para enfrentar a situação. De todos os casos diagnosticados, 60% correspondem a Ásia, África e América do Sul, mesmas regiões onde ocorrem 70% das mortes. Envolverde/IPS