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.
Ten years ago the equine influenza virus (EIV) A/H3N8, a common cause of respiratory infections in horses, turned up in dogs. Now Chinese researchers report that domestic cats in a lab setting are susceptible to the same virus and can spread it to other cats.
Writing in Emerging Infectious Diseases, the researchers report that they inoculated six cats intranasally with H3N8. A day later, they placed five pathogen-free cats in the same cages, and they kept three other cats in a separate room to serve as controls.
Both the inoculated cats and the contact cats became infected, as evidenced by typical signs of influenza, virus shedding, and histopathologic changes in the trachea and lungs, the report says. Clinical signs of illness developed from 2 to 9 days after infection in the inoculated cats and from 4 to 9 days after infection in the contact cats, but the illness was less severe in the contact cats. The control cats showed no evidence of infection.
The authors said it’s not surprising that the cats became infected, since feline infections with various influenza A viruses have been reported before.
“However, our finding of horizontal transmission of EIV among cats is significant,” they added. “If transmission occurs outside the laboratory, and if the basic reproduction rate is higher than 1.0, then EIV could potentially establish itself and circulate in this new host species.”
Why cats, unlike dogs, have not been infected naturally by H3N8 remains to be determined, but it could be because of lower transmission efficiency or feline behavior, the authors wrote.
TORONTO – Canada is in the process of evacuating its three-member mobile laboratory team from Sierra Leone over concerns for the safety of the scientists as the World Health Organization investigates how an African doctor who worked at the same field unit as the Canadians contracted Ebola.
The Public Health Agency of Canada said late Tuesday that the team is being recalled to Canada after people at the hotel complex where they were staying were diagnosed with Ebola. The agency said the Canadians do not appear to be sick but will be in voluntary isolation both on their trip home and after they return to the country.
The WHO’s director of communications, Christy Feig, said the organization is investigating how the doctor, a Senegalese epidemiologist, became infected with the virus. The unit where he and the Canadians were working did not treat patients; it was a support operation for a nearby treatment centre operated by Medecins Sans Frontieres.
“It could have been a straightforward thing; he was exposed in an accident with an infected patient, it could have been that simple,” Feig said Wednesday in an interview from Liberia.
“But it also is a little unusual so we want to give it a close look so we can make sure there’s not something about the set up there that’s putting more people at risk.”
The Senegalese doctor has been evacuated to Hamburg, Germany for care. He is the first person working on an Ebola outbreak through the WHO’s Global Outbreak Alert and Response Network to have contracted the disease.
The standard thinking on MERS-CoV is that it doesn’t spread very easily, other than in healthcare settings with weak infection control precautions. A new study looking for transmission of the virus in the households of Saudi Arabian patients in 2013 seems to fit well with that view, though it has some limitations.
An international team of researchers looked for MERS-CoV (Middle East respiratory syndrome coronavirus) infection in 280 household contacts of 26 patients who had confirmed cases, according to their report in today’s New England Journal of Medicine. They found evidence of secondary transmission in only 12 contacts, only 1 of whom actually got sick.
Other experts who looked at the study, however, raised some questions about whether all of the 12 contacts really caught the virus from the infected person in their household, as opposed to some other source.
Hunting for unrecognized infections
The research team included members from Saudi Arabia, Germany, the United States, the United Kingdom, and the Netherlands, with Christian Drosten, MD, of the University of Bonn as lead author and Ziad A. Memish, MD, of Saudi Arabia as senior author.
They observe that unrecognized transmission of MERS-CoV might explain why newly identified index cases—those in patients having no known contact with other cases—often can’t be linked to contact with animals. Hence they aimed to determine the rate of silent or subclinical infections in household contacts of index case-patients.
They focused on household contacts of the 26 index patients in Saudi Arabia who were found to have MERS-CoV from Jun 4, 2013, to Nov 5, 2013. The affected households were in Riyadh (16), Dammam (3), Al-Hasa (2), Hafr Al-Batin (2), Jubail (2), and Jeddah (1).
The team used two reverse-transcriptase polymerase chain reaction (RT-PCR) assays to test throat swabs from household contacts, and they also ran serologic (serum antibody) tests. The tests were done at varying intervals after the index patients fell ill.
Because serologic tests for MERS-CoV are not yet fully validated, the authors used a three-stage process, consisting of screening with an enzyme-linked immunosorbent assay followed by an immunofluorescence test and then by virus neutralization testing. Under a decree from the health ministry, all the household contacts were required to undergo the initial testing.
The 26 index patients had a median age of 55, and 17 were male. Twenty-four of them had coexisting illnesses, and 18 died. Before hospitalization, the patients had been sick at home for an average of 6 days.
The index patients had an average of 11 household contacts each. The median age of the household contacts was much lower, at 29, and 59 of them were no more than 16 years old. Forty-eight percent of the contacts were female, and 12% had a coexisting illness.
PCR and serologic test results
The dual RT-PCR tests were positive for 7 (2%) of the 280 contacts. One of these had mild symptoms when tested, and two had had contact with camels, which can carry MERS-CoV. All seven involved samples taken within 14 days after onset of illness in the index patients.
Serologic testing identified five additional infections, all in contacts who were sampled 13 days or longer after the index patient’s first symptoms. Four of these were found in the initial round of tests, and one more was identified in follow-up tests of samples taken between 2 and 6 months later. The follow-up testing was not required, and only 44 of the 280 contacts participated.
The 12 contacts who tested positive on RT-PCR or serologic assays represented 6 of the 26 households in the study. Their ages ranged from 3 to 74 years, but 11 of the 12 were under 40.
“Our findings suggest that persons in the first few decades of life without coexisting illnesses may be able to carry low levels of MERS-CoV RNA without obvious symptoms,” the report says. It adds that infected but asymptomatic healthcare workers were identified in a recent MERS outbreak in Jeddah.
The authors say the low number of contacts who agreed to provide a follow-up blood sample was an important limitation of the study. They blamed the low response on the stigmatization of MERS patients and discrimination against affected families at the time.
Because of the small number of follow-up serologic tests, the authors said they may have missed some contacts who had a delayed serologic response to infection. In addition, they said they couldn’t evaluate whether any of the index patients and contacts actually had common sources of MERS-CoV exposure, as opposed to the index patients passing the virus to the contacts.
Others raise questions
The latter possibility was a concern raised by Allison McGeer, MD, a microbiologist and infectious diseases consultant at Mt. Sinai Hospital in Toronto, who was consulted by the Saudi government about MERS in 2013 but was not involved in the study.
She observed that three of the contacts tested positive by RT-PCR just 4 days after illness onset in the index cases, which she found surprising: “That’s a lot of people testing positive early on.”
She said the median incubation period for MERS-CoV is about 5 days, and in the Al-Hasa outbreak in 2013, the median serial interval (the time between illness onset in an index case and the first secondary case) was 7.5 days.
“It’s not obvious to me that these are actually cases resulting from transmission in the household,” McGeer said, referring to the three patients who tested positive 4 days after the index patients got sick.
She also said she would have expected to see a larger number of secondary cases and wonders if some were missed, and added that she found the report difficult to read.
“I’m sympathetic to the difficulties of researching outbreaks and getting data, but we know that household transmission of MERS occurs, we know that asymptomatic and mild cases occur, we know people who are older likely have more severe disease—we knew all that before, and I’m not sure I know more now,” McGeer said.
Another expert, Connie Savor Price, MD, chief of infectious diseases at Denver Health and Hospital, shared McGeer’s concern about the difficulty of knowing whether some of the contact cases really represented secondary transmission.
“It is hard to know whether this truly represents household transmission or common exposure to the same source, which one could expect in a household setting,” she said.
But she added, “Having said that, we know that healthcare settings amplify transmission of infectious diseases, and MERS-CoV is no exception. Healthcare transmission—not household transmission—has been the primary mode of human-to-human transmission in KSA [Kingdom of Saudi Arabia] in recent months. Despite the limitations, this article still supports the view that MERS-CoV doesn’t spread very easily from person to person in non-healthcare settings.”
Drosten C, Meyer B, Muller MA, et al. Transmission of MERS-coronavirus in household contacts. N Engl J Med 2014 Aug 28;371(9):828-35 [Abstract]
Initial human testing of an investigational vaccine to prevent Ebola virus disease will begin next week by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.
PUNE: Rabies claimed another life in the city on Tuesday, taking the death toll this year to 18 so far.
Forty-five-year-old Rambhau Appa Tonde from Daund taluka died at the Naidu Infectious Diseases Hospital on August 26. Tonde was bitten by a dog on August 14. He did not take anti-rabies vaccine and fast-acting rabies antibodies on scheduled days which caused his death, said a civic official.
“Tonde was admitted to Naidu Hospital after his condition deteriorated. He developed symptoms like fear of water, air and was extremely breathless at the time of admission. He died at 8.30 pm on August 26,” said S T Pardeshi, medical officer of health, PMC.
“Tonde suffered a category-III dog bite wound. As per the medical history produced by the victim’s relatives, the man had not taken the anti-rabies vaccine on the scheduled days. He was also not administered rabies immunoglobulin, a ready-made antibody, which is extremely effective in deactivating the virus in category III dog-bite injury,” the doctor who attended Tonde said.
As per the World Health Organization, the incubation period for the infection is typically 1-3 months, but it may vary from a week to a year.
Rabies is a zoonotic disease (transmitted to humans from animals) that is caused by a virus. The disease affects domestic and wild animals, and is spread to people through close contact with infectious material, usually saliva, via bites or scratches.
According to the Association for Prevention and Control of Rabies in India, greater awareness about rabies and its timely treatment, combined with efforts to control the stray-dog population, pet-dog licensing and annual anti-rabies vaccination of animals, are necessary to control the infection. Experts have highlighted the needto create awareness about proper wound care and post-exposure vaccination must be reinforced to prevent rabies infection.