Role of mapping in preventing epidemics like Ebola

Role of mapping in preventing epidemics like Ebola

Role of mapping in preventing epidemics like Ebola


A review in The International Journal of Epidemiology has offered some practical suggestions for preventing a future epidemic like the recent Ebola crisis.
stop-ebola

In a future epidemic, more effective strategies must be put in place to stop the spread.

Prof. Tom Koch, of the University of British Columbia, asks how it could be that many of the best minds in infectious disease, epidemiology and disaster medicine missed the early spread of the Eboladisease so that it became a regional epidemic.

While insisting that all parties involved “labored heroically, often at great personal risk, to restrict the original outbreak and treat those affected by it,” Prof. Koch believes there are lessons to learn about containing future disease outbreaks in rural areas with minimal resources.

In his review, he focuses on the potential of mapping as a tool to help deal with future disasters.

Prof. Koch points out that limits on data relating to patient location and travel mapping made it harder to contain the Ebola crisis.

At the same time, regional disease protocols were not implemented soon enough, as nobody anticipated such an expansive epidemic.

Records now show that the 2014 epidemic probably began in 2013, when a 2-year-old boy in the village of Meliandou in Guinea’s Gue ́ckédo Prefecture first became infected.

Infections need to be appropriately mapped

However, local, national and international health officials assumed that, as in previous cases, this outbreak would be a static, and thus controllable, localized disease event.

Prof. Kock explains that infectious diseases have a spatial structure and that their spread depends on individual features that either promote or hinder their progress. Based on this, he argues that various forms of mapping could help to contain such diseases.

In the case of the Ebola epidemic, having no maps or census data for the region where the outbreak occurred made it difficult to apply aggressive quarantine programs, which could have isolated the villages where Ebola was active and protected those at risk from villagers who did not display symptoms.

Prof. Koch discusses the need to involve the community in mapping and education.

He says:

“Employing community members in the mapping also serves anthropologically, involving community members in the disease response, teaching them about an expanding viral event and its local effects. In areas where there is distrust of foreign or official health workers, this can be critical.”

Prof. Koch gives the example of the Nepal earthquake in 2015, where resources of Humanitarian Open Street Map and Digital Globe satellite data enabled 39 volunteers to create Quakemap.org, a crowd-sourced mapping program that enabled correlation of reports of earthquakes in individual villages to help ensure that supplies were directed where they were needed.

In connection with the Ebola crisis, he focuses on a strategy called diffusion mapping. In this approach, smaller scale maps are used in patient interviews to identify travel patterns of patients before they become symptomatic. This could be helpful in anticipating the number of patients likely to present with symptoms in time.

He describes the approach as “a potentially invaluable, if so far untested, approach that would rapidly characterize local travel patterns and thus the potential for regional disease expansion.”

Prof. Koch hopes that the review will help shape ideas about how mapping could help significantly in future outbreaks by contributing toward a prompt response.

Medical News Today recently reported on trials into the effectiveness and safety ofusing convalescent plasma to treat Ebola patients.

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Preventive malaria treatment for Ebola contacts cost-effective

Preventive malaria treatment for Ebola contacts cost-effective

Preventive malaria treatment for Ebola contacts cost-effective

Public health officials should consider preventive malaria treatment for contacts of patients with Ebola virus disease in areas where malaria transmission is high, according to a study published in The Lancet Infectious Diseases.

“Malaria is endemic in West Africa, so accurate diagnosis of Ebola virus disease is difficult when the disease is in the early stages, since symptoms resemble those of febrile malaria,” Cristina Carias, PhD, of the CDC’s National Center for Emerging and Zoonotic Infectious Diseases, and colleagues wrote. “As a result, 33% to 54% of patients admitted to [Ebola treatment units (ETUs)] during the 2014-2015 West Africa outbreak did not have Ebola virus disease. The provision of preventive malaria treatment to all contacts of patients with Ebola virus disease has thus been proposed as an option to prevent the onset of malaria fever and consequent inefficient allocation of ETU beds to patients with malaria, and exposure of these patients to Ebola virus.”

Carias and colleagues used a decision tree model to assess the economic feasibility of administering artemisinin-based combination treatment (ACT) to all contacts of patients with Ebola virus disease in West Africa.

The analysis lasted 1 year, roughly aligning with the West Africa Ebola outbreak. The researchers calculated the intervention’s cost per ETU admission averted by season (wet or dry), country (Liberia, Sierra Leone or Guinea) and age of contact (aged younger than 5 years, aged 5 to 14 years or aged 15 years and older). Sensitivity analyses were used to assess how results varied with malaria parasite prevalence in children aged 2 to 10 years, the daily cost of ETU stay, and the effectiveness of preventive malaria treatment and patients’ adherence to it.

From a health care perspective, administering ACTs to Ebola contacts resulted in cost savings for those of all ages in Liberia, Sierra Leone and Guinea, regardless of season, according to the researchers. In the wet season, preventive malaria treatment was estimated to reduce the chances of a contact being admitted to an ETU by 10% to 36%. Assuming 85% adherence to ACTs and taking into account the African population pyramid, the researchers expect ACTs to be cost saving in Ebola contacts across all age groups, even when malaria parasite prevalence in children aged 2 to 10 years is as low as 10%. During the wet season in Liberia, malaria preventive treatment was cost saving even as the average daily bed-stay costs were as low as $5 for children aged younger than 5 years, $9 for those aged 5 to 14 years, and $22 for those aged 15 years and older.

“This study provides a very strong justification for public health providers responding to an Ebola virus disease outbreak to consider distribution of preventive malaria treatment to contacts of patients with Ebola virus disease, in the context of an emergency response to Ebola virus disease outbreaks in malaria endemic areas,” Carias and colleagues wrote.

In a related editorial, Azra C. Ghani, PhD, and Patrick G. Walker, PhD, of the School of Public Health, Imperial College London, said extending ACT to areas with less intense seasonal transmission would not only be cost-effective as a malaria intervention, but it would reduce the burden on the health care system. This would, in turn, enable a more rapid response to future Ebola outbreaks.

“Any reduction in unnecessary admission to ETUs also has substantial benefits in terms of controlling the Ebola epidemic. Reducing the number of individuals in ETUs would not only be cost saving but also substantially relieve the pressure on an overburdened epidemic response,” Ghani and Walker wrote. “Additionally, it will reduce the potential for further transmission of Ebola virus disease within the ETUs.” – by Jason Laday

Study links

Carias C, et al. Lancet Infect Dis. 2015;doi:10.1016/S1473-3099(15)00465-X
Ghani CG, et al. Lancet Infect Dis. 2015;doi:10.1016/S1473-3099(15)00481-8.

Disclosure: The researchers report no relevant financial disclosures. Please see the full editorial for a list of the authors’ relevant financial disclosures.

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Article originally appeared at the Halio website on 11th January, 2016. Available at: http://www.healio.com/infectious-disease/emerging-diseases/news/online/%7B06d52d61-fd9c-4f74-999a-07eb553260b6%7D/preventive-malaria-treatment-for-ebola-contacts-cost-effective

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Pregnant women advised to avoid animals that are giving birth

Pregnant women advised to avoid animals that are giving birth

Pregnant women advised to avoid animals that are giving birth

Public Health Wales is reminding pregnant women to avoid close contact with animals that are giving birth.
Pregnant women who come into close contact with sheep during lambing or other farm animals that are giving birth may risk their own health, and that of their unborn child, from infections that such animals can carry.
Therefore Public Health England, the Department of Health, the Department for Environment, Food and Rural Affairs, the Animal and Plant Health Agency and the Health and Safety Executive, in association with the Welsh Government and Public Health Wales, the Scottish Government and Health Protection Scotland and the Departments of Agriculture and Rural Development (DARD) and of Health, Social Services and Public Safety (DHSSPS) in Northern Ireland have issued annual advice for a number of years that women who are or may be pregnant should avoid animals that are giving, or have recently given, birth.
Although the number of human pregnancies affected by contact with an infected animal is extremely small, it is important that pregnant women are aware of the potential risks and take appropriate precautions.
These risks are not only associated with sheep, nor confined only to the spring (when the majority of lambs are born). Cattle and goats that have recently given birth can also carry similar infections.
To avoid the possible risk of infection, pregnant women should:
  • not help ewes to lamb, or provide assistance to a cow that is calving or a nanny goat that is kidding;
  • avoid contact with aborted or new-born lambs, calves or kids or with the afterbirth, birthing fluids or materials (e.g. bedding) contaminated by such birth products;
  • avoid handling (including washing) clothing, boots or any materials  that may have come into contact with animals that have recently given birth, their young or afterbirths. Potentially contaminated clothing will be safe to handle after being washed on a hot cycle;
  • ensure contacts or partners who have attended lambing ewes or other animals giving birth take appropriate health and hygiene precautions, including the wearing of personal protective equipment and clothing and adequate washing to remove any potential contamination.
Pregnant women should seek medical advice if they experience fever or influenza-like symptoms, or if concerned that they could have acquired infection from a farm environment.
Farmers and livestock keepers have a responsibility to minimise the risks to pregnant women, including members of their family, the public and professional staff visiting farms.
Further advice is available to download from the document: More information on the following document... Q&A for pregnant women during lambing season

Source

Article originally appeared on the Public Health Wales Health Protection Division website on 11th January available at: http://www.wales.nhs.uk/sites3/news.cfm?orgid=457&contentid=39978

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‘One Health, One Medicine’ Using research to assist both man and beast

‘One Health, One Medicine’ Using research to assist both man and beast

‘One Health, One Medicine’ Using research to assist both man and beast

“Research funded by the Wellcome Trust and implemented jointly by UK and Kenyan-based institutions investigates epidemiology of zoonotic diseases-these are diseases transmitted between animals and people”

PAZ ProjectDrive into a shamba, a Kenyan small-holding, and you can observe first hand the close relationship rural Kenyans hold with their animals: Men ploughing the fields with teams of cattle; women milking cows and goats or using fresh dung to floor their houses; poultry, cats, dogs and children playing together. Pigs, goats and sheep wander in and out of houses, latrines and kitchens, picking at anything remotely edible, all categories of household wastes included.

All the while you are also made aware of the trappings of poverty: pot-holed tracks, no running water or electricity and children bearing the tell-tale pot bellies of parasitic worm infection. Livestock often show overt signs of disease, ill thrift and anaemia being particularly common.

A stereotypical view of Africa, maybe, but a view that is none-the-less a reality and that, when you stop to look, can give an insight into the diseases encountered by those living in such communities. In these marginalised communities, zoonotic diseases – pathogens transmitted between animals and people – exert a heavy burden.

The PAZ (People, Animals & their Zoonoses) project, funded by the Wellcome Trust, brings together a multidisciplinary team of scientists from the School of Biological Sciences at the University of Edinburgh, the International Livestock Research Institute in Kenya and the Kenya Medical Research Institute. Under the project human and animal health teams will visit more than 450 homesteads in Western Kenya over 3 years, collecting data and samples from people, cattle and pigs, while offering health checks and advice or referral to those who require it.

Bringing basic health care facilities directly to the people and livestock of Western Kenya is one of the outcomes of the project, although it is the future outcomes of this research on which the greatest value is placed. Following a ‘One Health’ paradigm, the project will address both human and animal health, and its research agenda includes an effort to assess the true burden of zoonotic diseases in both humans and livestock. The project is the first to focus on quantifying the importance of zoonotic diseases in the context of other infectious diseases, understanding in detail the factors that put livestock and people at risk. It will trial new field-appropriate diagnostic tests and work on designing livestock-targeted interventions that are reasonably cheap and easy to implement and that may have an impact on human public health.

The PAZ project brings together epidemiologists, veterinarians, medical health professionals and laboratory technologists working as a single team in a study area covering a large proportion of the Western Province of Kenya, stretching from Lake Victoria in the south along the Ugandan Border towards Mount Elgon in the North.

The important zoonotic diseases which will be studied by the project include Brucellosis, Bovine TB, Q-fever, endemic Rift Valley Fever, Cysticercosis and zoonotic Trypanosomiasis. The possibility of acquiring these diseases within most shambas is high, due to the abundance of risk factors, both observable to the naked eye and those of a more hidden nature. A natural environment conducive to transmission, regular close contact between people and their animals, access of those animals to human waste, little preventative health provision for domestic stock, inconsistent meat inspection, and poor quality food and forage for both humans and animals all contribute to a high risk of acquiring infections. In addition, the presence in these same populations of humans and livestock of other, non-zoonotic diseases, such as HIV/AIDS may increase the chance of individuals acquiring a zoonotic disease in the first place.

For many people in rural Kenya today, zoonotic disease will remain undiagnosed or misdiagnosed. The same is true for their livestock. A multitude of factors are involved in this under-diagnosis: a lack of health seeking behaviour, the prohibitive cost of medical services, lack of veterinary service delivery, poor diagnostic test availability and lack of awareness amongst the population, or even the local medical and veterinary services. This is well demonstrated by the ubiquitous diagnosis of malaria for anyone suffering a fever – while malaria is undoubtedly a very serious health issue, its over-diagnosis hides many other problems.

To compound this, people living in Kenya and similar countries may easily fall under the health policy radar – many are born, live and die without official record being made of them, they have a weak, or non-existent, political voice and the causes of their deaths are never recorded. Thus, while these zoonotic diseases are grouped as ‘neglected zoonotic diseases,’ it would be equally correct to identify them as ‘diseases of neglected populations’. Two tenants at the core of the PAZ project’s ‘One Health’ paradigm are the belief that human and animal health are irrevocably entwined and that the improvement of both requires close collaboration between the medical and veterinary professions with support from allied disciplines. The greater understanding of the link between human and animal health which the project aims to develop will mark the first step in addressing the problem of neglected zoonotic diseases internationally. (Eric M. Fevre – Lian F. Doble, University of Edinburgh,  www.atomiumculture.eu) – derstandard.at/1308680366514/One-Health-one-Medicine-Using-research-to-assist-both-man-and-beast

Article originally appeared at: http://derstandard.at/1308680366514/One-Health-one-Medicine-Using-research-to-assist-both-man-and-beast

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Deforestation linked to rise in cases of emerging zoonotic malaria

Deforestation linked to rise in cases of emerging zoonotic malaria

Deforestation linked to rise in cases of emerging zoonotic malaria

Research suggests environmental changes are driving increase in Plasmodium knowlesi malaria – an infection usually found only in monkeys – among people in Malaysia.

MacaqueA steep rise in human cases of P. knowlesi malaria in Malaysia is likely to be linked to deforestation and associated environmental changes, according to new research published in Emerging Infectious Diseases. The study, led by the London School of Hygiene & Tropical Medicine, is the first to explore how changes in land use are impacting the emergence of the disease.

Plasmodium knowlesi is a zoonotic malaria parasite, transmitted between hosts by mosquitoes, which is common in forest-dwelling macaque monkeys. Although only recently reported in humans, it is now the most common form of human malaria in many areas of Malaysia, and has been reported across southeast Asia. In recent years, Malaysia has seen widespread deforestation alongside rapid oil palm and other agricultural expansion. It is thought changes in the way land is used could be a key driver in the emergence of P. knowlesi, but until now this has not been investigated in detail.

The study focused on the Kudat and Kota Marudu districts in Sabah, Malaysia, covering an area of more than 3,000km² with a population of approximately 120,000 people. Researchers used hospital records for 2008-2012 to collect data on the number of P. knowlesi malaria cases from villages in the districts. Information collected from satellite data helped the team to map the local forest, land use, and environmental changes around 450 villages, in order to correlate how these changes might affect human infection.

They found that the number of P. knowlesi cases was strongly linked to deforestation in areas surrounding the villages.  This could be explained by a number of factors, including humans coming into closer contact with the forest inhabited by the macaques and the mosquito vectors, due to employment in tree clearance and expanding agriculture. Another factor could be that as land use changes in this way, macaque populations are becoming more densely concentrated in areas of forest where humans are present.

Lead author Kimberly Fornace, Research Fellow at the London School of Hygiene & Tropical Medicine, said: “The dramatic rise in the number of P. knowlesi malaria cases in humans in Malaysia in the past ten years has been most common in areas with deforestation, as well as areas that are close to patches of forest where humans, macaques and mosquitoes are coming into closer and more frequent contact. This suggests that there is a higher risk of P. knowlesi transmission in areas where land use is changing, and this knowledge will help focus efforts on these areas and also predict and respond to future outbreaks. Given our findings, we view deforestation as having distinct public health consequences which need to be urgently addressed.”

The findings show the study region had undergone significant environmental changes, with many villages substantially affected by deforestation. During the five-year study alone, 39% of the region’s villages lost more than 10% of the forest cover in their surrounding 1km radius, and half of villages lost more than 10% within a 5km radius. Overall, forest cover in Kudat and Kota Marudu declined by 4.8% during the study period.

The findings also confirmed that P. knowlesi is the most common cause of human malaria cases in the region.

The authors note that some cases of malaria may have been unreported as they were asymptomatic or resolved without treatment. P. knowlesi can be mistaken for other forms of human malaria in microscope diagnosis, however the authors adjusted for this uncertainty in the study. They also highlight that the environmental data were limited as they could not discriminate between types of forest or crops, meaning further work is needed to investigate whether vegetation type is a risk factor for P. knowlesi.

This study was funded by the Biotechnology and Biosciences Research Council, Economic and Social Research Council, Medical Research Council, and Natural Environment Research Council, through the Environmental and Social Ecology of Human Infectious Diseases Initiative (ESEI).

The research was carried out in collaboration with the Infectious Disease Society Kota Kinabalu Sabah, Malaysia; Hospital Queen Elizabeth Clinical Research Centre, Malaysia; Menzies School of Health Research, Australia; Sabah Department of Health, Malaysia; and the University of Glasgow, UK.

Publication:

Article originally appeared on the London School of Hygiene and Tropical Medicine website on 18th December, 2015 at: http://www.lshtm.ac.uk/newsevents/news/2015/deforestation_malaria_link.html

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Bats, People and a complex web of disease transmission

Bats, People and a complex web of disease transmission

Bats, People and a complex web of disease transmission

It might seem strange that after millennia of human history, outbreaks of new, ’emerging’ diseases that we’ve never seen before still regularly occur around the world, some of which go on to become pandemic. However, this may not be so surprising considering how quickly and how intensively the world is changing – expansion of populations, industries, and travel and trade networks are all thought to play a role.

BatsMany current strategies to deal with emerging diseases are reactive, rather than proactive, i.e. the response is focused on dealing with outbreaks after they happen. But what if we could improve our response by projecting where the next outbreak will be and how it will occur? Or better yet, prevent it altogether?

This is the aim of the PREDICT programme, a consortium of worldwide disease biologists. Working with several PREDICT members from the EcoHealth Alliance, our team at University College London, in collaboration too with the STEPS-led Dynamic Drivers of Disease in Africa Consortium, aimed to quantify how these global changes affect the risk of emerging bat-borne viruses.

Bats and disease

The majority of human diseases are zoonoses, that is, they originate via transmission from animals, and bats are no exception. Many devastating viral outbreaks of the last 15 years are suspected to have their origins in bats, from Nipah virus disease in 1999 and SARS in 2002 to the recent outbreaks of Ebola disease and Middle East respiratory syndrome (MERS) in the last several years.

We started by mapping out the potential distribution of each of the 33 viruses shared between bats and humans, collaborating with the Vonhof group at Western Michigan University who have been collecting together data on all viruses known in bats, and which species they infect.

Next, we collected together spatial data on global changes and the wider environment, as well as human density and agriculture. This also included data on domestic animals as bat viruses can sometimes reach people through our livestock, and bushmeat hunting, as bats are hunted and consumed in many parts of the world. It’s critical to understand not just whether these factors affect disease emergence, but also through what means.

Virus risk hotspots

We grouped factors together depending on whether they were likely to increase risk through either increasing richness of viruses (the total number of viruses present) or increasing transmission potential from contact between bats and humans.

Using spatial statistical modelling, we then combined all of this into a single risk map. What we see from this is that, overall, there is a large hotspot of risk in sub-Saharan Africa, including West Africa, where the most recent Ebola virus outbreaks have occurred.

Global map of risk of bat-human shared viruses from statistical model based on ecological and human drivers.

However, when we break down the model into whether the risks occur through richness of viruses or bat-human contact, the resulting maps look very different. Central and South America seem to be a risk hotspot because a naturally high diversity of viruses occurs there, and associations in our model suggest this is a result of a high diversity of bat hosts. Contrastingly, South and East Asia seem to a be a risk hotspot because of high bat-human contact potential, a reflection of high densities of humans and domestic animals, as well as bushmeat practices in some areas.

This tells us something critical – that those places where wild bat populations host many viruses do not seem to be the same as those places where people frequently come into contact with bats, and that both contribute to risk in a different way.  Our risk maps take that first step in untangling the complex, multi-step process behind the emergence of a new bat-borne virus in humans.

One Health

In the last decade, there has been a real shift in the way public health is viewed to a much more modern, holistic – or ‘One Health‘ – approach. This acknowledges that animal health and human health are fundamentally connected through our wider ecology, and has guided much of our thinking in the Dynamic Drivers of Disease in Africa Consortium.

Future work will be able to delve deeper into the specific connections between bats and people that could help prevent future disease outbreaks. Although there is much we have yet to understand, what is clear is that bats should not be vilified for their association with emerging diseases. They can be key contributors to environmental stability and ecosystem services, and – admittedly, more sentimentally – they’re fascinating animals, whose world we’ve only just ventured into.

Kate Jones is Professor of Ecology and Biodiversity at University College London and a partner in the STEPS-led Dynamic Drivers of Disease in Africa Consortium. She will be speaking at the One Health for the Real World: zoonoses, ecosystems and wellbeing symposium, being held at the Zoological Society of London, 17-18 March 2016.

Quantifying Global Drivers of Zoonotic Bat Viruses: A Process-Based Perspective’, authored by Liam Brierley, Maarten J. Vonhof , Kevin J. Olival, Peter Daszak and Kate E. Jones, is published in The American Naturalist.

Article originally appeared on the Steps Centre website at: http://steps-centre.org/2016/blog/bats-people/ authored by Kate Jones and Liam Brierley on 5th January 2016

Kate Jones and Liam Brierley
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