Middle East Respiratory Syndrome Corona Virus (MERS-CoV) – What do we know?

Middle East Respiratory Syndrome Corona Virus (MERS-CoV) – What do we know?

In the summer of 2012 in Saudi Arabia a strange corona virus infection was isolated from a patient with acute pneumonia and renal failure. Subsequently, a series of laboratory diagnostics divulged a novel coronavirus later known as Middle East Respiratory Syndrome Coronavirus (MERS COV).

Following the virus identification, a new case was reported from a Qatar patient in the UK and a cluster of hospital cases were reported among health workers in Zarqa, Jordan. There was ineffable fear that the world was fronting another pandemic after the Severe Acute Respiratory Syndrome (SARS).

MERS-CoV worldwide distribution

As of June 3rd 2015, there have been 1,179 confirmed cases of MERS and 442 fatalities in 25 nations representing a case fatality rate of 37.49%. South Korea is the latest country to report two deaths and 35 cases in the largest outbreak outside Saudi Arabia. The vast majority of the South Korean cases have      been acquired from hospitals with the fast spread attributed to the fact that family members often stay with patients in their hospital rooms.

MERS-CoV infection in humans occurs either as outbreaks as witnessed in Jeddah, Saudi Arabia where 255 confirmed cases were reported in four months or as isolated cases. The infection’s clinical presentation ranges from asymptomatic to a very severe pneumonia with the acute respiratory distress syndrome, septic shock and multi-organ failure ensuing in death.

Serological studies have confirmed camels have antibodies against the virus. In addition, virus detection by reverse transcription PCR and sequencing has confirmed that these antibodies are likely to be caused by infection with a similar virus strains that infect humans, although a formal confirmation of the role of camels in the epidemiology of the virus is still elusive. Transmission has largely remained human to human with a few isolated primary cases having a histo-ry of contact with camels, suggesting that they are a source of human infection.

A number of questions regarding the dis-ease have remained difficult to answer:

  1. What is the reservoir of the virus, and are there multiple animal species that may form a reservoir community?   If yes, which ones?
  2. The infection has predominantly affect-ed older people.  Is this related to abil-ity to fight infection, or is it exposure related?
  3. The evolutionary background of MERS-CoV is unclear; antibodies against the virus were found in Kenyan camels during a period spanning from 1992 to 2013. This implies that the virus exist-ed in camels long before it was identified and before it jumped to the human population. Nevertheless, the appearance of human cases in the last few years might indicate some kind of mutation of virus that allows it be become human infective.  If this is the case, could it spread rapidly though the human population?  If this mutation has occurred, has it occurred in multiple locations simultaneously?
  4. What is the risk of human infection from camel populations outside the Middle East (eg in Kenya)

Performing nasal swabIn collaboration with a number of partners, including St Louis Zoo, the Mpala Research Center and the Erasmus Medical University, we are investigating elements of the epidemiology of MERS-CoV in camels in Kenya to help answer some of the above questions.

These studies are an extension of the Urban Zoo project’s activities investigating camel value chains in Kenya and Nairobi.

Article by Dishon Muloi (dshnmuloi@gmail.com)

Urban Zoo Project in the A4NH 2014 Annual report

Urban Zoo Project in the A4NH 2014 Annual report

1.6.2.1 A4NH Annual report 2014Zoonoses, or diseases that can pass between animals and humans, lead to 2.4 billion cases of illness and 2.2 million deaths per year, according to ILRI scientist, Delia Grace. The 13 major culprits include bacterial infections such as brucellosis and leptospirosis, as well as other infections, like bovine tuberculosis. It is estimated that more than 75 percent of diseases that have emerged over the past 20 years originated in animals.
Such diseases are particularly likely to develop when people and animals live in close proximity to each other, increasing the opportunity for the transfer of pathogens. With agricultural intensification stemming from increased consumer demand for milk and meat, animals and humans are increasingly crowded within the same space, often in unsanitary conditions. In Nairobi, more than 60 percent of the population lives around the edges of the city in crowded, informal settlements.
Most lack basic amenities, such as toilets, running water, and sewers. Many residents keep livestock close by, although it is illegal to keep animals within city limits. The United Nations predicts that these makeshift suburbs will continue to grow in Nairobi, surpassing six million people by 2025.
The Urban Zoo project is led by the University of Liverpool (UK) with a major funding award from the UK Environmental and Social Ecology of Human Infectious Diseases Initiative, led by the UK Medical Research Council, and is aligned to A4NH at ILRI. It looks at the health implications of changes in agriculture, particularly theintensification of livestock in urban and peri-urban areas. The project examines ways in which pathogens are introduced and spread through livestock commodity value chains among urban populations around Nairobi, Kenya.
The project includes nine academic partners in Kenya and the UK that coordinate with the Kenyan government and policy institutions as well as a network of INGOs. Urban Zoo research covers meat and milk value chains, human nutrition in poor urban populations (with additional funding from the Leverhulme Centre for Integrative Research on Agriculture and Health, LCIRAH), food chain risk assessments, and integrated disease surveillance, among other areas. Researchers are mapping the path of meat and milk products, and their associated disease risks in Nairobi. Through this, they hope to better understand how
diseases emerge in order to prevent future outbreaks.
“We’re redrawing the map of Nairobi, not based on geography, but on the connectedness of animal and human populations, in terms of bacteria that they share.” Eric Fèvre
Featured in the A4NH 2014 Annual report on page 23. You can read the report by clicking here

Whole Genome Sequencing By Melissa Ward, CIIE Research Fellow

Whole Genome Sequencing By Melissa Ward, CIIE Research Fellow

Melissa genomeThe power of next generation sequencing is allowing us to gain a more detailed understanding than ever before about how bacteria spread. I am hugely excited to be a part of the Urban Zoonoses project, which will generate a vast amount of bacterial isolates along with meta-data at an unprecedented level of detail.We will be performing whole genome sequence analysis of bacterial samples collected through many strands of the Urban Zoonoses project, from humans, livestock, food, wildlife and the environment. I will use state-of-the art methods for integrating the bacterial genetic sequence data with information about the time, loca-tion and host from which the bacteria were sampled. By combining epidemiological and demographic infor-mation with the genetic data, we will be able to under-stand the E. coli diversity within Nairobi, and how this differs across socioeconomic groups, in different housing types and in relation to livestock keeping practices.

From the bacterial genome sequences we can also look for genes of interest, such as those conferring bacterial virulence or resistance to antibiotics. By examining the set of genes carried by bacteria from different individuals, hosts or locations, we can make inferences about reservoirs of antibiotic resistance and pinpoint potential hotspots for disease outbreaks, with a particular emphasis on zoonotic transmissions.

I have previously used whole genome sequence analysis to investigate the transmission of S. aureus between livestock and humans, and have also used phylogenetic techniques to help understand the origins of the HIV-1 group M epidemic. I am currently assessing the utility of whole genome sequencing as a tool for identifying epidemiologically related E. coli infections in collaboration with the Scot-tish E. coli O157 Reference Laboratory.

My involvement with the Urban Zoonoses project is made possible through a Junior Research Fellowship at the Centre for Immunity, Infection and Evolution at the University of Edinburgh, and a Sir Henry Wellcome Postdoctoral Fellowship from the Wellcome Trust.

Melissa Ward is a CIIE Research Fellow at the University of Edinburg.

 

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