Human Virus Linked to Deaths of Endangered Mountain Gorillas; Finding Confirms That Serious Diseases Can Pass to Gorillas from People

ScienceDaily (Mar. 29, 2011) — For the first time, a virus that causes respiratory disease in humans has been linked to the deaths of wild mountain gorillas, reports a team of researchers in the United States and Africa.

The potential for disease transmission between humans and mountain gorillas is of particular concern because over the past 100 years, mountain gorillas have come into increasing contact with humans.

The finding confirms that serious diseases can pass from people to these endangered animals.

The researchers are from the non-profit Mountain Gorilla Veterinary Project; the Wildlife Health Center at the University of California, Davis; the Center for Infection and Immunity at Columbia University; and the Rwanda Development Board.

Their study, which reports the 2009 deaths of two mountain gorilla that were infected with a human virus, was published online by the journalEmerging Infectious Diseases, a publication of the U.S. Centers for Disease Control and Prevention.

"Because there are fewer than 800 living mountain gorillas, each individual is critically important to the survival of their species," said Mike Cranfield, executive director of the Mountain Gorilla Veterinary Project and a UC Davis wildlife veterinarian. "But mountain gorillas are surrounded by people, and this discovery makes it clear that living in protected national parks is not a barrier to human diseases."

Humans and gorillas share approximately 98 percent of their DNA. This close genetic relatedness has led to concerns that gorillas may be susceptible to many of the infectious diseases that affect people.

The potential for disease transmission between humans and mountain gorillas (Gorilla beringei beringei) is of particular concern because over the past 100 years, mountain gorillas have come into increasing contact with humans. In fact, the national parks where the gorillas are protected in Rwanda, Uganda and the Democratic Republic of Congo are surrounded by the densest human populations in continental Africa.

Also, gorilla tourism -- while helping the gorillas survive by funding the national parks that shelter them -- brings thousands of people from local communities and around the world into contact with mountain gorillas annually.

The veterinarians of the Mountain Gorilla Veterinary Project, who monitor the health of the gorillas and treat individuals suffering from life-threatening or human-caused trauma and disease, have observed an increase in the frequency and severity of respiratory disease outbreaks in the mountain gorilla population in recent years.

Infectious disease is the second most common cause of death in mountain gorillas (traumatic injury is the first). "The type of infection we see most frequently is respiratory, which can range from mild colds to severe pneumonia," said co-author Linda Lowenstine, a veterinary pathologist with the UC Davis Mountain Gorilla One Health Program who has studied gorilla diseases for more than 25 years.

The two gorillas described in the new study were members of the Hirwa group living in Rwanda. In 2008 and 2009, this group experienced outbreaks of respiratory disease, with various amounts of coughing, eye and nose discharge, and lethargy. In the 2009 outbreak, the Hirwa group consisted of 12 animals: one adult male, six adult females, three juveniles and two infants. All but one were sick. Two died: an adult female and a newborn infant.

Tissue analyses showed the biochemical signature of an RNA virus called human metapneumovirus (HMPV) infecting both animals that had died. While the adult female gorilla ultimately died as a result of a secondary bacterial pneumonia infection, HMPV infection likely predisposed her to pneumonia. HMPV was also found in the infant gorilla, which was born to a female gorilla that showed symptoms of respiratory disease.

The study's UC Davis authors are Cranfield, Lowenstine and Kirsten Gilardi, co-director of the UC Davis Wildlife Health Center's Mountain Gorilla One Health Program. The lead author is Gustavo Palacios, a virologist at the Center for Infection and Immunity at Columbia University in New York. Other authors are from the Mountain Gorilla Veterinary Project, Columbia University and the Rwanda Development Board.

The research was supported by Google.org; the U.S. National Institutes of Health; the Emerging Pandemic Threats PREDICT program of the U.S. Agency for International Development; and a grant from the David and Lucile Packard Foundation.

About mountain gorillas

With only about 786 individuals left in the world, mountain gorillas are a critically endangered species. Mountain gorillas live in central Africa, with about 480 animals living in the 173-square-mile Virunga Volcanoes Massif, which combines Volcanoes National Park in Rwanda, Virunga National Park in the Democratic Republic of Congo, and Mgahinga National Park in Uganda. The remaining population lives within the boundaries of the 128-square-mile Bwindi Impenetrable National Park in Uganda.

About the Mountain Gorilla Veterinary Project

The Mountain Gorilla Veterinary Project, a U.S.-based nonprofit organization, is dedicated to saving mountain gorilla lives. With so few animals left in the world today, the organization believes it is critical to ensure the health and well being of every individual possible. The organization's international team of veterinarians, the Gorilla Doctors, is the only group providing wild mountain gorillas with direct, hands-on care. The Mountain Gorilla Veterinary Project partners with the UC Davis Wildlife Health Center to advance "one-health" strategies for mountain gorilla conservation. http://www.gorilladoctors.org.

Vírus desconhecido causou doença misteriosa na China

Doença misteriosa

Em 2006, um grande número de agricultores na região central da China começou a cair vítima de uma doença misteriosa.

Marcada pela febre alta, distúrbio gastrointestinal, a doença apresentou uma taxa de mortalidade inicial terrível, chegando a 30% das pessoas que apresentaram os primeiros sintomas.

Cientistas do Centro Chinês para Controle e Prevenção de Doenças correram para o local do surto.

Com base em indícios de DNA, eles rapidamente concluíram que o surto havia sido causado por anaplasmose granulocítica humana, uma bactéria transmitida pela picada de carrapatos.

Vírus desconhecido

Agora, porém, estudos mais detalhados demonstraram que a conclusão original estava errada.

Na verdade, um vírus anteriormente desconhecido e muito perigoso tem sido o responsável pelos surtos sazonais da doença nas seis províncias mais populosas da China.

"Esperávamos encontrar uma infecção bacteriana se comportando de forma inesperada - a anaplasmose humana tem menos de um por cento de taxa de letalidade nos EUA, e raramente causa dor abdominal, vômito ou diarreia," explica o Dr. Xue-Jie Yu, da Universidade do Texas.

"Mas o que encontramos foi um novo vírus até agora desconhecido," afirma ele. A descoberta foi anunciada em um artigo que será publicado no New England Journal of Medicine.

Vírus da Febre Severa com Síndrome de Trombocitopenia

Os pesquisadores batizaram o novo patógeno de Vírus da Febre Severa com Síndrome de Trombocitopenia, e catalogaram-no na família Bunyaviridae, juntamente com o hantavírus e com o vírus da Febre de Rift Valley.

Uma investigação posterior, com dados de novos surtos, estimou a taxa de mortalidade do vírus em uma média de 12 por cento, ainda alarmante.

Os cientistas tiveram certeza de que se tratava de um vírus depois que soros obtidos de pacientes infectados mantiveram sua capacidade de matar células mesmo depois de terem passado por um filtro que bloqueia todas as bactérias.

Testes genéticos não conseguiram gerar uma correspondência com nenhum vírus conhecido, o que levou os pesquisadores a se concentrarem na identificação do novo vírus.

Vírus transmitido pelo carrapato

Mas os cientistas que analisaram o problema em primeiro lugar estavam certos em uma coisa: o vírus é transmitido por carrapatos.

"Esta parece ser uma doença transmitida por carrapatos, a doença surge quando os carrapatos saem, no final de março até o final de julho.

"Felizmente, embora o ciclo de vida do vírus ainda não esteja claro, sabemos que os seres humanos são um beco sem saída para ele - não temos transmissão de humano para humano, como tivemos com a SARS," conclui Yu.

Newly Discovered Virus Implicated in Deadly Chinese Outbreaks

ScienceDaily (Mar. 22, 2011) — Outbreaks of a mysterious and deadly disease in central China have been linked to a previously unknown virus. Five years ago, large numbers of farmers in central China began falling victim to an mysterious disease marked by high fever, gastrointestinal disorder and an appalling mortality rate -- as high as 30 percent in initial reports.

Investigators from the Chinese Center for Disease Control and Prevention hurried to the scene of the outbreak. On the basis of DNA evidence, they quickly concluded that it had been caused by human granulocytic anaplasmosis, a bacteria transmitted by tick bites.

Now, though, subsequent studies have shown that original conclusion was incorrect, and that a previously unknown and dangerous virus has been responsible for seasonal outbreaks of the disease in six of China's most populated provinces.

"We expected to find a bacterial infection behaving in an unexpected way -- human anaplasmosis has a less than one percent fatality rate in the U.S., and it rarely causes abdominal pain or vomiting or diarrhea," said Dr. Xue-Jie Yu of the University of Texas Medical Branch at Galveston, lead author of a paper on the discovery now appearing in the "online advance" section of the New England Journal of Medicine. "Instead, we found an unknown virus."

Researchers have dubbed the newly discovered pathogen Severe Fever with Thrombocytopenia Syndrome virus, and placed it in the Bunyaviridae family, along with the hantaviruses and Rift Valley Fever virus. Later investigation has placed its mortality rate at 12 percent, still alarmingly high.

Yu, a specialist in tick-borne bacteria like the species responsible for HGA, first suspected that a virus might be responsible for the outbreaks after close examination of patients' clinical data showed big differences from symptoms produced by HGA, and blood sera drawn from patients revealed no HGA or HGA antibodies.

Yu became certain that a virus was at fault after sera taken from patients retained its ability to kill cells, despite being passed through a filter that blocked all bacteria. Still, initial genetic tests failed to generate a match with a known pathogen.

"Clearly, we had a virus, but what virus?" Yu said. "I told the people I was working with that they needed to be even more careful, because we were working with an unknown."

That caution seemed appropriate when electron microscope studies of deactivated virus particles revealed what appeared to be a hantavirus -- associated in Asia with hemorrhagic fever and in the Americas with a deadly pulmonary syndrome. But when Yu and his colleagues managed to extract the virus' entire genetic code, they found that it didn't match any other known virus.

When researchers from the Chinese Center for Disease Control and Prevention led by study author Dr. Yu Wang analyzed sera taken from 241 symptomatic patients from Henan, Hubei, Shandong, Anhui, Jiangsu and Liaoning provinces, they found 171 contained either the previously unknown virus itself or antibodies against it. In addition, the scientists found the virus in 10 out of 186 ticks collected from farm animals in the area where the patients lived.

"This seems to be a tick-borne disease, and the disease comes out when the ticks come out, from late March to late July," Yu said. "Fortunately, even though the full life cycle is not clear, we know that for the virus humans are a dead end -- we don't have human-to-human transmission as we did with SARS."

Nova ameaça na picada do mosquito da dengue

Pesquisadores brasileiros diagnosticaram nos últimos meses três casos de infecção por um vírus pouco conhecido no país, o chikungunya, também transmitido pelo mosquito Aedes aegypti, e pelo Aedes albopictus, o da febre amarela. E o Ministério da Saúde anunciou hoje o início da vigilância e do controle no Brasil da febre de chikungunya.

Nos três casos confirmados pelo Ministério da Saúde, os pacientes se contaminaram em outros países. O primeiro foi em 25 de agosto, um surfista carioca, de 41 anos, que visitou a Indonésia. O segundo foi em 29 de setembro, um homem, de 55 anos, que vive em São Paulo, que também andou pela Indonésia. O último caso é de uma mulher, de 25 anos, que teve a doença confirmada no último dia 3. Ela esteve na Índia, segundo notícia publicada no site da Universidade de Brasília, onde trabalha o pesquisador Pedro Tauil, do Núcleo de Medicina Tropical e um dos que investiga os casos no Brasil.

Os sintomas de chikungunya - do grupo dos alfavírus -, lembram o da dengue, como febre de 39 graus, dores pelo corpo, principalmente articulares. Alguns casos cronificam e as dores duram quase seis meses. Daí o nome chikungunya, que numa das línguas oficiais da Tanzânia, significa "aqueles que se dobram".

Na entrevista, Tauil comentou que o diagnóstico não é difícil e que laboratórios brasileiros, como o Instituto Evandro Chagas, em Belém do Pará, são capazes de identificar a doença: "se você pensa que é dengue, deu negativo, você procura chikungunya e acha chikungunya". O tratamento é similar ao da dengue, com o uso de paracetamol, antiinflamatórios e até corticoides.

A infecção, assim como na dengue, não se manifesta de imediato. Leva até sete dias. Por enquanto, ele diz que não é preciso entrar em pânico. Primeiro porque a chikungunya costuma ser mais benigna que a dengue, e os casos estão restritos ao Sudeste Asiático e à ilhas do Pacífico. Porém, já temos três casos importados aqui e podem chegar outros. Então é hora de alerta.

O pesquisador brasileiro não acredita que um mesmo mosquito pode abrigar os dois vírus, dengue e chikungunya ou febre amarela e chikungunya: "isso é pouco provável." Segundo o coordenador do Programa de Nacional de Controle da Dengue do Ministério da Saúde, Giovanini Coelho, não há circulação do vírus nas Américas. Ela ocorre apenas em países da África e do sudeste asiático, e o índice de letalidade é baixo: menos de 1%. O Ministério da Saúde aconselha a quem for viajar para África e sudeste da Ásia adotar medidas de prevenção, como uso de repelentes e mosquiteiros.