In the fight against Ebola, mapping fruit bat habitats could be one important step, says a geoinformatics researcher at Sweden’s Royal Institute of Technology.
Like the Black Death that ravaged medieval Europe, the Ebola virus’ progress through remote areas of West Africa is enabled by lack of understanding about the disease, including its causes and transmission.
Mapping technology however will give responders to the crisis in Africa the upper hand in stopping the spread of the deadly disease, says Skog, a researcher in geoinformatics at Sweden’s KTH Royal Institute of Technology.
Skog’s research has produced a method that medical professionals can use to visualise the geographical distribution of a disease over time. In his research, Skog has explored the relationship between geography and disease distribution in major epidemics of the past, including the Black Death, the Russian Flu pandemic of 1889, the Asiatic Influenza of 1957 and the swine flu. He says the historical data provides a basis for predicting the course of future epidemics and pandemics.
“My research and method can also be used to report the current state of a pandemic, or predict how extensive the spread will be. And where the disease will strike next,” Skog says.
In fact, the way in which Black Death spread during the mid 14th, century bears a no small resemblance to today’s Ebola epidemic, he says. Both diseases were hosted by small mammals — black rats and fruit bats, respectively. But ultimately it was humans that enabled its spread.
“The Black Death was very much depending on total lack of knowledge regarding the etiology of the disease and how to avoid further transmission,” Skog says. “That is also the case for the mainly remote locations where Ebola now is spread.”
Fruit bats are believed to be the natural hosts of Ebola. These bats are among the creatures that residents of rural West Africa hunt for “bush meat.” The disease is also spread by the droppings of the bat, and it is believed to have spread to other types of bush meat, as well as monkeys and pigs that are raised for slaughter.
“The local population is getting part of their nourishment from bush hunting, leading to contact with the virus that is transmitted via body fluids,” Skog says, suggesting that closer study of the fruit bat could provide vital answers.
“A guess of mine is that the number of infected fruit bats is a determining factor for an Ebola outbreak,” he says. “Are there any known factors that may have changed the ecosystem in favor of the bats? Are the bats affected by the virus too? Do fruit bats always carry the Ebola virus or is the virus fatal to them as well? If so the percentage of infected bats will vary over the years also depending on the immunology of the species.”
There are a number of geoinformation technology options available to public health organizations that have sent field crews to respond to the crisis. These, Skog says, including equipping field workers with hand-held GPS devices that feed a central database with data and findings regarding locations of bodies, possible infections and diagnosed cases personnel.
“The data can easily be centrally monitored and used for decisions and policies to mitigate the spread,” he says. “Using satellite imagery, population centers can be localized. Collected disease data can also be compared and analysed with environmental and climatologic data to support other efforts to control the spread.”
For instance, assuming that fruit bats are the reservoir for the ebola virus, Skog says it would be of interest to find out if the first detected cases in an outbreak are located in or close to a fruit bat habitat. “If the environmental and climatologic parameters for fruit bat habitats can be defined, there is a chance these habitats could be mapped using existing map data and satellite or airborne imagery,” he says.
“Then risk areas could be monitored and preventive measures could be performed by health authorities. If the natural reservoir is in fact some other animal, positioning the first cases in each outbreak would still give a clue about what to look for.”
CHICAGO (September 10, 2014) – Nationally, hand hygiene adherence by healthcare workers remains staggeringly low despite its critical importance in infection control. A study in the October issue of Infection Control and Hospital Epidemiology, the journal of the Society for Healthcare Epidemiology of America (SHEA), found that healthcare workers’ adherence to hand hygiene is better when other workers are nearby.
“Social network effects, or peer effects, have been associated with smoking, obesity, happiness and worker productivity. As we found, this influence extends to hand hygiene compliance, too,” said Philip Polgreen, MD, an author of the study. “Healthcare workers’ proximity to their peers had a positive effect on their hand hygiene adherence.”
Researchers at the University of Iowa’s Carver College of Medicine used a custom-built, badge-based system to estimate hand hygiene compliance and opportunities, as well as the location and proximity of every healthcare worker in the medical intensive care unit of the University of Iowa Hospital and Clinics during a 10-day period for 24-hours a day. Badges were randomly provided at the start of each shift to physicians, nurses and critical care staff. The badges collected information from healthcare workers within proximity and hand hygiene compliance when entering and exiting a patient room. In total, more than 47,000 hand hygiene opportunities were recorded.
The estimated hand hygiene rate was 7 percent higher (28 percent vs 21 percent) when healthcare workers were in close proximity to peers when compared with the rate when healthcare workers were alone. In general, the researchers found that the magnitude of the peer effects increased in the presence of additional healthcare workers, but only up to a point.
The authors note that the results speak to the importance of the social environment in healthcare and have important implications for understanding how human behavior affects the spread of diseases within healthcare settings.
A genetic region responsible for red blood cell invasion was among a small number of areas found to differ between the genomes of malaria parasites that affect chimpanzees and Plasmodium falciparum, the parasite responsible for the deaths of more than half a million children each year.
Out of a genome of approximately 5,500 genes, researchers found that most genes have directly equivalent counterparts between the human and primate parasites. However, portions of the P. falciparum genome that differed most profoundly from the P. reichenowi parasite that infects chimpanzees were found to encode proteins that help the parasite to bind to and invade red blood cells, which is where the parasite grows and multiplies.
“Discovering that the key differences lie in genes responsible for red blood cell invasion reassures us that we’ve been looking in the right place,” says Dr Thomas Otto, first author at the Wellcome Trust Sanger Institute. “Researchers have identified surface proteins as promising vaccine candidates already; and our finding adds more support, showing that it is the difference in the parasites’ surface proteins that determine which host it will infect.”
This is the first time that an essentially complete genome has been produced for a malaria parasite that infects such a close relative of humans. It provides the first systematic view of the differences between parasites that infect humans and those that infect our close relatives. Human malaria emerged from the Great Apes, so this comparison using chimpanzee malaria is the closest that scientists have come to a full catalogue of the changes associated with parasites switching from our primate relatives into humans.
Plasmodium parasites export proteins to the surface of red blood cells, allowing infected red blood cells to stick to the wall of blood vessels. In human malaria, the best characterised of these proteins are encoded by a highly variable family of genes, allowing the parasites to evade the host immune response and continue the infection. Surprisingly basic rules about this gene family are preserved between chimpanzee and human malaria: despite huge variation in the individual sequence of these surface antigen genes, their absolute numbers and the numbers of sub-types are remarkably preserved. By contrast, other surface antigen repertoires differed very significantly in their numbers.
“Since P. reichenowi and P. falciparum split apart, the major surface antigen gene family has not expanded or contracted; it’s locked at some kind of optimised level,” says Dr Matt Berriman, senior author at the Sanger Institute.
DNA used for this research was obtained by the Centre for Disease Control from a chimpanzee infected with a strain of P. reichenowi isolated in the 1950s. This chimpanzee was subsequently cured of the malaria infection. Additional blood samples were collected from orphaned infant chimpanzees infected in the wild with a similar parasite called P. gaboni. The samples were obtained from chimpanzees undergoing routine health checks at a primate sanctuary in Gabon, West Africa.
KUNMING, Sept. 7 (Xinhua) — As rabies sweeps across dog populations in China’s southwest Yunnan province almost 5,000 canines have been culled in an anti-rabies campaign.
With 5 human deaths in the past three months, the municipal government in Baoshan City is carrying out a campaign to stop the threat, with more than 4,900 dogs killed and 100,000 vaccinated.
The human casualties, one in July and four in August, were reported in four townships and villages in Shidian County. Longling County and Longyang District have also reported dog bites.
The municipal government of Baoshan has issued an urgent notice urging authorities to control the animals and cull stray dogs.
Rabies is a class 2 notifiable disease in China with cases rare in the past half-decade.
In 2006, at least 16 people died of rabies in east China’s Shandong Province after a rash of dog attacks.
The recall of raw pork products due to possible E. coli contamination has been expanded to more stores in Calgary and Edmonton.
Raw pork products bought at Trimming Fresh Meat (6219 Centre St. N.W.) between July 15 and July 22 and products from Hiep Hoa Asian Food (4710 17 Ave S.E.) between July 15 and July 29 should be thrown out or returned to the store where they were purchased.
According to the Canadian Food Inspection Agency website, the products may not look or smell spoiled, however they still have the potential to make consumers sick.
The expanded recall also includes frozen pork spring rolls, pork buns and pork wontons from Vihn Fat Food Products (10630 97 St.) in Edmonton sold between July 10 and Sept. 5, which should be thrown out or returned to the point of purchase.
Alberta Health Services said 153 people were diagnosed with E. coli between July 10 and Sept. 3, with 19 having to be hospitalized and five of those suffering the most serious form of the disease, which affects the kidneys.
AHS officials said 45 people were hospitalized in Calgary and 46 in Edmonton and the remainder at smaller centres around the province.
Steps can be taken to avoid food-borne illnesses, including washing your hands thoroughly using hot, soapy water — especially after using the washroom or changing a diaper — cooking pork and beef products to at least 71C (160F) and thoroughly washing any cooking utensils that touch raw meat.
The Ebola outbreak in West Africa has killed 2,288 people, with half of them dying in the last three weeks, the World Health Organization (WHO) says.
It said that 47% of the deaths and 49% of the total 4,269 cases had come in the 21 days leading up to 6 September.
The health agency warned that thousands more cases could occur in Liberia, which has had the most fatalities.
The outbreak, which was first reported in Guinea in March this year, has also spread to Sierra Leone and Nigeria.
In Nigeria, eight people have died out of 21 cases, while one case of Ebola has been confirmed in Senegal, the WHO said in its latest update.
On Monday, the agency called on organisations combating the outbreak in Liberia to scale up efforts to control the outbreak “three-to-four fold”.
Ebola spreads between humans by direct contact with infected blood, bodily fluids or organs, or indirectly through contact with contaminated environments.
However, the WHO says conventional means of controlling the outbreak, which include avoiding close physical contact with those infected and wearing personal protective equipment, were not working well in Liberia.
The reason for this remains unclear; however, experts say it could be linked to burial practices, which can include touching the body and eating a meal near it.
There are also not enough beds to treat Ebola patients, particularly in the capital Monrovia, with many people told to go back home, where they may spread the virus.
Sophie-Jane Madden, of aid agency Medecins Sans Frontieres, told the BBC that health workers at the largest treatment centre in Monrovia were completely overwhelmed: “Our teams are every day turning away people who are desperately seeking healthcare.”
Meanwhile, the US says it will help the African Union mobilise 100 African health workers to the region and contribute an additional $10m (£6.2m) in funds to deal with the outbreak.
The announcement comes as a fourth US aid worker infected with the deadly virus was transported to a hospital in Atlanta for treatment.
The identity of the aid worker has not yet been revealed.
Two other aid workers who were treated at the same hospital have since recovered from an Ebola infection.
Separately on Tuesday, the UN’s envoy in Liberia said at least 80 Liberian health workers had died from Ebola, according to the Associated Press.
Karin Landgren described the outbreak as a “latter-day plague” that was growing exponentially. She added that health workers were operating without proper protective equipment, training or pay, in comments to the UN Security Council.
Using tracer viruses, researchers found that contamination of just a single doorknob or table top results in the spread of viruses throughout office buildings, hotels, and health care facilities. Within 2 to 4 hours, the virus could be detected on 40 to 60 percent of workers and visitors in the facilities and commonly touched objects, according to research presented at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), an infectious disease meeting of the American Society for Microbiology.
There is a simple solution, though, says Charles Gerba of the University of Arizona, Tucson, who presented the study.
“Using disinfecting wipes containing quaternary ammonium compounds (QUATS) registered by EPA as effective against viruses like norovirus and flu, along with hand hygiene, reduced virus spread by 80 to 99 percent,” he says.
Norovirus is the most common cause of acute gastroenteritis in the United States, according to the Centers for Disease Control and Prevention (CDC). Each year, it causes an estimated 19-21 million illnesses and contributes to 56,000-71,000 hospitalizations and 570-800 deaths. Touching surfaces or objects contaminated with norovirus then putting your fingers in your mouth is a common source of infection.
In the study, Gerba and his colleagues used bacteriophage MS-2 as a surrogate for the human norovirus, as it is similar in shape, size and resistance to disinfectants. The phage was placed on 1 to 2 commonly touched surfaces (door knob or table top) at the beginning of the day in office buildings, conference room and a health care facility. After various periods of time (2 to 8 hours) they sampled 60 to 100 fomites, surfaces capable of carrying infectious organisms (light switches, bed rails, table tops, countertops, push buttons, coffee pots handles, sink tap handles, door knobs, phones and computer equipment), for the phages.
“Within 2 to 4 hours between 40 to 60% of the fomites sampled were contaminated with virus,” says Gerba.
In the intervention phase cleaning personal and employees were provided with QUATS disinfectant containing wipes and instructed on proper use (use of at least once daily). The number of fomites on which virus was detected was reduced by 80% or greater and the concentration of virus reduced by 99% or more.
There are 90 different EPA-registered quat-based formulations available under 1500 different brand names that are formulated to kill norovirus on solid surfaces. These are available as wipes or ready-to-use liquids or concentrates for use by professional maintenance teams.
“The results shown that viral contamination of fomites in facilities occurs quickly, and that a simple intervention can greatly help to reduce exposure to viruses,” says Gerba.
The pathogens posing the greatest risk to Europe based upon a proxy for impact have been identified by University of Liverpool researchers using a ‘big data’ approach to scientific research.
The researchers from the University’s Institute of Infection and Global Health ranked the top 100 pathogens affecting humans and the top 100 affecting domestic animals using a system which, they believe, will help governments across the continent plan for risks associated with the spread of infectious diseases, including as a result of climate change, and for biosecurity.
The top risk for both humans and animals was E.coli and in humans this was followed by two forms of HIV, Hepatitis C and Staphylococcus aureus, a bacteria which causes food poisoning and is increasingly resistant to antibiotics.
To compile the list, the researchers used the EID2 database developed at Liverpool. This is a comprehensive record of over 60 million scientific papers, electronic sources and textbooks associated with infectious diseases. They cross-referenced the number of papers which dealt with a particular pathogen with the number of citations it attracted to give a score based on the amount of interest and need for scientific research into it.
Dr Marie McIntyre led the study. She said: “Risk assessments are incredibly time consuming because of the number of diseases which must be taken into account and people having to start from scratch for each one. This approach enables us to gauge the level of interest in a huge number of pathogens or diseases very quickly.”
The method used in the study is known as the Hirsch Index and while the study authors acknowledge factors such as there being high public interest leading to more studies of a particular illness, they believe that because it is objective and evidence-based it will be a useful complement and guide to more traditional methods of risk assessment and can be used to produce a shortlist of pathogens for authorities to focus on.
Dr McIntyre said: “The amount of work carried out by scientists on a particular disease is a good indication of how much of a threat it is. This approach is a quick and accurate method of aggregating the work carried out by thousands of scientists around the world and using it to guide policy at a continent-wide level.”
Rabies (and rabies virus, its causative agent) is usually transmitted through the bite of an infected animal into muscle tissue of the new host. From there, the virus travels all the way to the brain where it multiplies and causes the usually fatal disease. An article published on August 28th in PLOS Pathogens sheds light on how the virus hijacks the transport system in nerve cells to reach the brain with maximal speed and efficiency.
Pathogens that travel in the blood can spread throughout the body without much effort, courtesy of the heart’s pumping action. Those traveling outside the blood stream and needing to cover large distances—like rabies virus which depends on the nerve cell network—need to utilize other means of transport. Nerve cells (or neurons) in the periphery, i.e. the outskirts of the body, as opposed to the central nervous system or CNS), are highly asymmetric: they have a cell body from which a long protrusion called an axon extends to another nerve cell or a target organ like muscle, along a specific transmission route. Axons can measure several hundred times the diameter of the cell body, and, in addition to rapid transmission of electric impulses, they also transport molecular materials over these distances.
Rabies virus is known to somehow use this transport system, and Eran Perlson, from Tel Aviv University, Israel, and colleagues set out to examine the details of how this occurs. The researchers set up a system to grow asymmetric nerve cells in an observation chamber and use live cell imaging to track how rabies virus particles are transported along the axons.
They focused on the p75NTR receptor, a protein which is found on the tips of peripheral neurons and known to bind a small molecule called NGF (for nerve growth factor). When NGF binds p75NTR, both are taken up into the neuron and move in acidic bubbles called “vesicles” toward the cell body. The researchers found that rabies virus behaves very similar to NGF: it binds p75NTR, both are internalized, and subsequently found in acidic vesicles that move toward the nerve cell body.
Rabies virus is known to be able to infect neurons in the absence of p75NTR. However, when the researchers grew nerve cells that had no p75NTR in their observation chamber, they found that virus transport along the axon is less frequent and much slower. p75NTR-independent transport was also more erratic, with a larger proportion of viruses moving in the wrong direction, i.e. away from the cell body and towards the tip, suggesting that p75NTR facilitates the directed fast movement of the virus. When the researchers measured the speed of transport, they found that when rabies virus is transported with p75NTR, it moves at about 8 centimeters (a bit more than 3 inches) per day. Surprisingly, this is considerably faster (by about 40%) than the transport speed for NGF, the regular partner of p75NTR.
The authors summarize: “Our study shows that rabies virus can not only hijack the transport systems of the neuron, but might also manipulate the axonal transport machinery to facilitate its own arrival at the cell body, and from there to the central nervous system at maximum speed”.
Ebola has struck an area in the northern part of the Democratic Republic of Congo (DRC), with at least two confirmed fatal cases, but authorities say it is not the same strain as in West Africa, according to media reports and the World Health Organization (WHO).
DRC Health Minister Felix Kabange Numbi announced on state television yesterday that 2 of 8 samples from patients in Djera, in the Boende region of Equateur province, tested positive for Ebola, according to an Associated Press (AP) report yesterday. The story described the cases as fatal.
Kabange said officials believe Ebola has killed 13 people in the region, including five health workers, according to the story. He said 11 people were sick and in isolation and that 80 contacts were being traced.
“This epidemic has nothing to do with the one in West Africa,” Kabange said.
Further test results expected
The DRC’s national laboratory reported that the Ebola strain is different from the one causing the epidemic in West Africa, the WHO said on Twitter yesterday. The agency said the government is “organizing” further tests to better characterize the strain.
More test results were expected today, WHO spokesman Gregory Hartl said yesterday on Twitter. He said there “could be 2 different strains here, meaning two different events/outbreaks.”
The WHO said earlier that an outbreak of hemorrhagic gastroenteritis was the cause of 70 deaths in the Boende region in recent weeks. In Twitter comments last week, Hartl said those deaths were not from Ebola, but yesterday he tweeted that he had been given “premature information from the field.” He said samples had tested positive in the DRC lab and the tests would be checked by another lab.
DRC’s seventh Ebola outbreak
Djera is a collection of villages more than 1,200 kilometers (745 miles) from the DRC capital, Kinshasa, and more than 600 kilometers from the provincial capital, Mbandaka, the AP reported.
Confirmation of Ebola prompted the DRC to deploy a response team to the affected area immediately, working with the WHO and other partners, the WHO said yesterday.
The DRC has had six previous Ebola outbreaks since the disease was discovered there in 1976, according to WHO data.