Medical Microbiology Research Center

Núcleo de Pesquisa em Microbiologia Médica – Universidade Federal do Rio Grande – FURG

Migrating humans may have killed off Neanderthals by accident

Story highlights

  • Study suggests Neanderthal extinction linked to diseases carried from Africa by humans
  • Infections likely to have been passed to Neanderthals include tapeworm, tuberculosis, stomach ulcers, types of herpes

(CNN)It appears modern humans may have some blood on our hands. A new study published in the American Journal of Physical Anthropology suggests that Neanderthals may have gone extinct because of tropical diseases carried by humans migrating out of Africa.

“Humans migrating out of Africa would have been a significant reservoir of tropical diseases,” said lead author, Charlotte Houldcroft from the University of Cambridge’s Division of Biological Anthropology, in a statement. “For the Neanderthal population of Eurasia, adapted to that geographical environment, exposure to new pathogens carried out of Africa may have been catastrophic.”
Researchers at Cambridge and Oxford Brookes universities analyzed DNA from ancient bones and pathogen genomes. They concluded that some infectious diseases are probably thousands of years older than previously believed.
There is evidence that humans caught viruses from other hominins before moving out of Africa. There is even evidence that our human ancestors mated with Neanderthals thousands of years ago and exchanged disease-related genes. So researchers argue that it’s safe to say humans could have passed diseases on to Neanderthals when they moved into Europe.
“As we now know that humans bred with Neanderthals, and we all carry 2% to 5% of Neanderthal DNA as a result, it makes sense to assume that, along with bodily fluids, humans and Neanderthals transferred diseases,” said Houldcroft.
Infections likely to have been passed from humans to Neanderthals include tapeworm, tuberculosis, stomach ulcers and types of herpes, according to the study.
The researchers suggest that herpes simplex 2, which is the virus that causes genital herpes, was passed to humans in Africa about 1.6 million years ago. Helicobacter pylori, a strain of bacteria that causes stomach ulcers, likely infected humans for the first time in Africa at least 88,000 years ago and first arrived in Europe about 52,000 years ago. But recent evidence suggests that Neanderthals became extinct about 40,000 years ago, supporting this new theory that modern humans are responsible for killing off Neanderthals.
Infectious diseases were previously thought to have spread quickly when agriculture developed about 8,000 years ago and humans began living in larger groups surrounded by animals. But new research argues that diseases existed much earlier than previously thought.
“Once agriculture came along, these diseases had the perfect conditions to explode, but they were already around,” said Houldcroft.
Researchers say that the infections would not have all happened at once, as they did when Christopher Columbus and other Europeans arrived in the Americas and eradicated indigenous populations. Instead, they would have spread between small groups of about 15 to 30, weakening them and making it nearly impossible to survive.
Many theories exist to explain the demise of the Neanderthal population, including climate change, human cognitive superiority, competition for food due to humans hunting with dogs and wolves, and direct competition and violence between humans and Neanderthals, said Houldcroft.
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She believes that the extinction is probably due to a combination of factors.
“Infectious diseases exchanged between humans and Neanderthals are likely to have been just one of many factors making it harder for Neanderthals to survive in Europe alongside modern humans,” said Houldcroft. “I don’t think any single factor was solely responsible, and we may never know which theory is correct, although we can continue to look for more evidence and try to test different theories.”

Alert: Refugees Face a New Threat From Infectious Disease

As Europe confines Syrian refugees to mass camps while they wait to be processed, many troubling aspects have arisen. One health experts are raising the alarm about is the rising tide of infectious diseases that could threaten the refugee population.

A gathering of health experts at the European Congress of Clinical Microbiology and Infectious Diseases conference in Amsterdam earlier this week raised concerns that a lack of coordinated EU policy on how to handle Syrian refugees and migrants is creating a potential for a serious infectious disease outbreak that could bring back some diseases that have been eradicated from Europe.

There is a persistent myth that any influx of migrants or refugees can spread diseases when those people are resettled in their new home countries. Some media sites have chosen to misrepresent what the health experts are saying in this latest discussion as vindication of general anti-refugee rhetoric.

However, the situation is more complex than that and, the researchers have said, there is probably little risk to European nations as a whole.

To understand the problem, we have to look at the current situation. Normally, refugees and migrants are carefully screened for infectious diseases. When they are introduced into their new homes, where general standards of living are high and access to medical care is easy, any diseases that somehow managed to get through screening can be diagnosed and treated during routine medical care.

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All the while, the general population is shielded against these infections due to regular vaccination programs and herd immunity. This means that the refugee population can integrate and share in that herd immunity.

Yet, the researchers have reportedly raised concerns that the sheer number of Syrian refugees and migrants fleeing war torn countries has led to this usual process breaking down. Refugees are highly vulnerable due to exhaustion and hunger which will have worked to reduce their immunity.

When you throw in the squalid conditions of some of the camps in which these people are being detained as they move between countries, and a general lack of easily accessible health care on top of that, the potential for a serious infectious outbreak is high.

Furthermore, the conference heard from experts that because Europe hasn’t standardized its screening procedures for infections like MRSA and HIV, more cases could slip through, and in particular with HIV being notoriously difficult to catch unless infection occurred some months ago.

Add to that a significant pressure within Europe from the anti-vaccination groups, which have tried to erode policies on routine vaccinations, there is some cause for action to do whatever we can to drive down infections before they get out of hand. Indeed reports suggest that some infectious diseases may be on the rise in certain areas.

The conference heard how Turkey, where there has been an influx of millions of refugees, has seen a rise in the tick-borne hemorrhagic fever popularly known as the Crimean-Congo virus. Research has also mapped a potential uptick in MRSA infections in Norway, as well as things like salmonella infections in refugees in Germany, which of course has taken in more refugees than mostly any other European nation. Evidence was also presented on measles outbreaks among refugees in France.

It’s important to again stress that these infections do not appear to pose a danger to the wider population, namely because vaccination programs are holding those diseases at bay and, besides, infections usually require close contact. However, for hospitals, the chance of drug-resistant infections like MRSA is troubling.

More than that though, the pressing concern is how we help refugees and improve their medical care as they enter their new home countries, something that will help ensure the health of the entire country’s population.

To do that, money will need to be invested in creating better general conditions for housing people as they move between and into countries. The current camps are wholly inadequate and could exacerbate infectious disease outbreaks.

Furthermore, more uniform and evidence-based screening procedures will need to be used to ensure that refugees and migrants are getting the proper health checks they need.

Rather than allowing this to feed into anti-immigrant sentiment, the conference heard that action needs to be taken for refugees and not because they pose a wider health risk to their new countries of residence but because we owe these at-risk populations the care that every human being deserves.

Italian public health expert Alberto Matteelli is quoted as saying, “The fact itself that they are marginalized and they do not integrate into the community in Europe is the cause of their disease, and protects the European community from being infected. The risk is for themselves. They are a vulnerable population that needs to be protected.”

There is currently a serious lack of resources for Syrian refugees whether they remain in Jordan or are escaping to Europe. Care2 petitioners are calling on the United States Congress to aid the UN Food Program to ensure that Syrians are not allowed to starve while this international crisis is resolved. To find out more, please visit and sign the Care2 petition.


Evidence Clear That Zika Causes Microcephaly, Other Birth Defects

In what has been called an unprecedented association, Zika virus is causally related to microcephaly and other severe fetal brain abnormalities, according to the Centers for Disease Control and Prevention (CDC) (N Engl J Med 2016 Apr 14. [Epub ahead of print]).

“This is an unprecedented association,” said CDC Director Tom Frieden, MD, MPH, during a press briefing announcing the report findings. “Never before in history has there been a situation where a bite from a mosquito could cause a devastating malformation. Never before have we seen an illness spread by a mosquito linked to a birth defect.”

Dr. Frieden said scientists at CDC confirmed mounting evidence of the link, “affirming our early guidance to pregnant women and their partners to take steps to avoid Zika infection and to health care professionals who are talking to patients every day. We are working to do everything possible to protect the American public.”

Accumulating Evidence
The report noted that no single piece of evidence provides conclusive proof that Zika virus infection is a cause of microcephaly and other fetal brain defects. Instead, increasing evidence from several recently published studies and a careful evaluation using established scientific criteria supports the researchers’ conclusions.

This finding means that a pregnant woman who is exposed to Zika virus is at increased risk for having a baby with these developmental problems. It does not mean, however, that all women who have Zika virus infection during pregnancy will delivery a child with neurological problems; some infected women have delivered babies that appear to be healthy, according to the CDC.
Establishing this causal relationship between Zika and fetal brain abnormalities is an important step in driving additional prevention efforts, focusing research activities and reinforcing the need for direct communication about the danger of Zika. Although one important question about causality has been answered, many questions remain, Dr. Frieden said.
Answering these will be the focus of ongoing research to help improve prevention efforts, which ultimately may help reduce the effects of Zika virus infection during pregnancy.
“The science now shows what hundreds of … families impacted by Zika virus have suspected all along: Zika virus is causing the tragic increases in microcephaly cases and other serious brain defects,” Dr. Frieden said.
The CDC is not changing its current guidelines as a result of this finding. Pregnant women should continue to avoid traveling to areas where Zika is actively spreading. If a pregnant woman travels to or lives in an area with active Zika virus transmission, she should speak with her health care provider and strictly follow steps to prevent mosquito bites. In addition, pregnant women should use protection during sexual activity with a man who has been to an area where there is Zika virus, even if he does not show signs of infection. The virus can be transmitted sexually.
The CDC encourages women and their partners in areas with active Zika transmission to engage in pregnancy planning and counseling with their health care providers, so that they can mitigate the risks.

About Zika Virus Disease – CDC

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Neanderthals may have died of diseases carried by humans from Africa

Diseases and infections passed on by the ancestors of modern humans when they moved out of Africa and into Europe may have helped wipe out the Neanderthals who previously dominated the continent.

The unfortunate Neanderthals, who would only have developed resistance to the diseases of their European environment, are most likely to have been infected with a bacterium that causes stomach ulcers, the virus that causes genital herpes, tapeworms and tuberculosis.

The impact on the Neanderthals was described as catastrophic by the scientists behind the new research, who published their findings in the American Journal of Physical Anthropology. The diseases and infections to which the hunter-gatherers were exposed would have made them less able to find enough food and remain healthy. The diseases would have spread through sexual contact between the two species.

Researchers at Cambridge and Oxford Brookes Universities, who have been studying pathogen genomes and ancient DNA, now believe some infectious diseases are far older than had been believed.

Dr Charlotte Houldcroft, from the division of biological anthropology at Cambridge, said: “Humans migrating out of Africa would have been a significant reservoir of tropical diseases. For the Neanderthal population of Eurasia, adapted to that geographical infectious disease environment, exposure to new pathogens carried out of Africa may have been catastrophic.”

Houldcroft, who also studies modern infections at Great Ormond Street hospital, said the result would not have been a swift decimation of native populations, as happened when Europeans arrived in the Americas in the 15th century.

“It’s more likely that small bands of Neanderthals each had their own infection disasters, weakening the group and tipping the balance against survival,” she said.

The researchers describe Helicobacter pylori, a bacterium that causes stomach ulcers, as highly likely to have been passed by humans to Neanderthals. It is estimated to have first infected humans in Africa between 88,000 to 116,000 years ago, and in Europe 52,000 years ago.

Herpes simplex 2, the virus that causes genital herpes, is another likely candidate. Evidence in the genome of the disease suggests it was transmitted to humans in Africa 1.6m years ago from another, currently unknown hominin species that in turn acquired it from chimpanzees.

Houldcroft and her colleague Simon Underdown of Oxford Brookes are challenging the view that the spread of infectious diseases exploded with the evolution of agriculture about 8,000 years ago, which saw denser and more settled human populations coexisting with livestock.

Instead, they believe that many diseases traditionally thought to have been caught by humans from herd animals were actually in the human population far earlier, and passed from them to the animals.

“Hunter-gatherers lived in small foraging groups. Neanderthals lived in groups of between 15 and 30 members, for example. So disease would have broken out sporadically, but would have been unable to spread very far. Once agriculture came along, these diseases had the perfect conditions to explode, but they were already around,” she said.

Scientists have long puzzled over the disappearance of the Neanderthals, a species very close in body shape and brain size to modern humans, which largely died out about 40,000 years ago, having dominated Europe for thousands of years.

The Neanderthals did not disappear without trace. Recent research suggesting that up to 3% of modern Eurasians’ DNA is Neanderthal has overturned earlier theories that the two species did not mate.

Five things to know about the flu vaccine

ACIP: Flu vaccine 59% effective to date

Although data is incomplete and several weeks remain in the influenza season, estimates from the CDC’s Advisory Committee for Immunization Practices indicated that the influenza vaccine has been 59% effective through Feb. 12. In addition, the vaccine was 51% effective against the H1N1 viruses responsible for most illnesses this season, 76% effective against all influenza B viruses and 79% effective against the B/Yamagata lineage of B viruses, according to estimates from the U.S. Flu VE Network. Read more.

More than half of infants, toddlers not fully vaccinated against flu

More than 50% of children aged 6 to 23 months are not fully vaccinated against influenza, according to recent research in Pediatrics.

Data showed that full vaccination rates of children in the study increased from 4.8% (2002-2003 season) to 44.7% (2011-2012 season). Despite this increase, the proportion of Hispanic (40.2%) and non-Hispanic black children (35.3%) fully vaccinated in 2012 was lower than the overall proportion. Those ethnicities also had lower full vaccination coverage than non-Hispanic white children for each influenza season. Read more.

LAIV inferior to inactivated vaccine for influenza AH1N1 in children

During the 2013-2014 season, risk for influenza was significantly greater in children vaccinated with the live-attenuated influenza vaccine compared with children, particularly those aged 2 to 8 years, vaccinated with the inactivated influenza vaccine (OR = 5.36; 95% CI, 2.37-12.13). Read more.

Flu vaccine does not increase risk for surgical patients

Recent findings published in Annals of Internal Medicine showed that influenza vaccination did not increase the risk for post-discharge fever in surgical patients, nor did it significantly increase most health care utilization among these patients. Read more.

Seasonal influenza vaccination during pregnancy reduces stillbirths

Women who received seasonal trivalent influenza vaccine during pregnancy were 51% less likely to experience stillbirth than those who did not receive the immunization, according to a study published in Clinical Infectious Diseases.

The findings are consistent with previous data, which suggested that maternal influenza vaccination could reduce stillbirths during an influenza pandemic. Read more.

After Nearly 39 Million Deaths, a Cure for HIV Could Be Just 3 Years Away

Cancer might be the disease that gets the vast majority of attention these days, but infectious diseases are actually the biggest global killers.

As a perfect example, take human immunodeficiency virus (HIV), a disease that attacks the cells of the immune system and leaves a person vulnerable to infections. According to statistics from amfAR, the Foundation for AIDS Research, there are nearly 37 million people living with HIV today, and approximately 1.2 million people died from the disease in 2014. Since the disease was discovered, nearly 78 million people have contracted HIV, of which nearly half (39 million) have died from AIDS-related causes (HIV evolves into AIDS when the disease has progressed and few infection-fighting CD4+ white blood cells remain).

But there could be great news right around the corner for HIV/AIDS sufferers.

An HIV cure could be right around the corner
Based on a report released a little over two weeks ago from researchers at the Lewis Katz School of Medicine at Temple University, and published in the journal Scientific Reports, scientists appear to have devised a way to eliminate HIV from the DNA of CD4+ T-cells.

The process, known as CRISPR/Cas9, works by targeting the genetic code of HIV that inserts into CD4+ T-cells. After taking blood from an infected patient, researchers genetically modify the Cas9 protein to seek out this genetic code. Once located, the Cas9 protein releases a nuclease enzyme, which in effect removes the HIV virus from the genetic code of the CD4+ T-cell and allows the loose ends of the T-cells’ genome to repair themselves.


Microbes can play games with the mind

The bacteria in our guts may help decide who gets anxiety and depression

By Laura Sanders 9:30am, March 23, 2016

The 22 men took the same pill for four weeks. When interviewed, they said they felt less daily stress and their memories were sharper. The brain benefits were subtle, but the results, reported at last year’s annual meeting of the Society for Neuroscience, got attention. That’s because the pills were not a precise chemical formula synthesized by the pharmaceutical industry.

The capsules were brimming with bacteria.

In the ultimate PR turnaround, once-dreaded bacteria are being welcomed as health heroes. People gobble them up in probiotic yogurts, swallow pills packed with billions of bugs and recoil from hand sanitizers. Helping us nurture the microbial gardens in and on our bodies has become big business, judging by grocery store shelves.

These bacteria are possibly working at more than just keeping our bodies healthy: They may be changing our minds. Recent studies have begun turning up tantalizing hints about how the bacteria living in the gut can alter the way the brain works. These findings raise a question with profound implications for mental health: Can we soothe our brains by cultivating our bacteria?

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On the night of March 24, 1882, Robert Koch announced in Berlin Physiological Society, the Mycobacterium tuberculosis was the cause of tuberculosis. Surely this was a memorable day for Medical Microbiology, but after 134 years we have much to celebrate. Although we have diagnostics and effective drugs methods, TB still kills three people every minute around the world and, from 2015, became the first cause of mortality among infectious diseases, overcoming the HIV / AIDS . This is a great and unspeakable disgrace to humanity in general. Certainly we need to invest in research and the transfer of its results to the user and the health system. We urgently need a diagnosis poin-of-care and a shorter and effective drug treatment against active TB, latent TB and resistant TB. We also need effective biomarkers to identify individuals susceptible to infection and developing TB or relapse after treatment of active TB, finally we lack even an effective vaccine. But the major bottleneck is the lack of political commitment by governments, which by its transience and electoral political logic, move, most of the time, blindly, without listening to the social and academic segments, which in experience should compose, permanently the set of actors who plans and executes the control of TB.
In this March 24 should reflect the role of each segment in the control of TB and particularly the role of the TB network (REDE TB –Brazil) in this scenario. What our story points is that our greatest mission as a network, has been facing the challenge of reducing the gap between state, academia, civil society and companies, seeking to include and coordinate efforts that may have as an outcome the reduction of this plague. Adversity has been one more stimulus for strengthening the TB network (REDE TB –Brazil) ) which more than one institution is a concept of integration and collaboration between different segments, with different looks seek to join efforts to control TB.


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