New tool better estimates pandemic threats

March 5, 2013, Public Library of Science

A simple new method better assesses the risks posed by emerging zoonotic viruses (those transmissible from animals to humans), according to a study published in PLOS Medicine this week. Dr. Simon Cauchemez and colleagues from Imperial College London in the UK and the Centers for Disease Control and Prevention in the US show that the new tool can produce transmissibility estimates for swine flu (the H3N2v-M virus), allowing researchers to better evaluate the possible pandemic threat posed by this virus. Until now, estimates of transmissibility were derived from detailed outbreak investigations, which are resource intensive and subject to selection bias. In this study, the authors develop a method to derive unbiased estimates of transmissibility with more limited data.

This study has important health policy implications because of the large numbers of people that could potentially be harmed by emerging viruses. Zoonotic viruses primarily cause occasional infections in exposed to reservoir species (the animal species harboring the virus) because the pathogens are usually poorly adapted for sustained human-to-human transmission. However, zoonotic viruses are under strong to acquire the ability for human-to-. Dr. Cauchemez and colleagues show that the novel approach described in this paper will be useful in assessing human-to-human transmissions during zoonotic outbreaks.

The researchers developed a mathematical model of , which only requires data from routine surveillance and standard case investigations. They showed that the pandemic potential of a zoonotic virus could be estimated simply from the proportion of cases infected by the natural reservoir. The authors then applied their new approach to assess the human-to-human transmissibility of H1N1v, H1N2v and H3N2v viruses (in particular that of the H3N2v-M virus) from US for the period December 2005 to December 2011 and Nipah virus in Malaysia and Bangladesh, as well as to a non-zoonotic pathogen Vibrio cholerae in the Dominican Republic. This study demonstrates the applicability of this novel approach to estimating the reproduction number R (or the number of individuals infected by a case), during zoonotic and certain non-zoonotic outbreaks.

The technique for estimating R described in this paper is simple and robust and does not require as much investigative effort as existing methods, say the authors. However, a key limitation of this new approach is that it is designed to estimate R during subcritical outbreaks. If it is not a subcritical outbreak, other methods are needed to estimate R.

Dr. Lyn Finelli, Surveillance and Outbreak Response Team (Influenza Division, CDC) and co-author on the paper said: "Outbreaks of the H3N2v-M virus largely took place at livestock exhibitions with thousands of visitors every day. It is very hard to perform detailed outbreak investigations and effectively trace cases in such settings since visitors are widely dispersed. The approach presented in the paper, is simple, requires few data, and was very useful in assessing transmissibility of the virus from the data available."

Explore further: CDC preparing vaccine for new swine flu

More information: Cauchemez S, Epperson S, Biggerstaff M, Swerdlow D, Finelli L, et al. (2013) Using Routine Surveillance Data to Estimate the Epidemic Potential of Emerging Zoonoses: Application to the Emergence of US Swine Origin Influenza A H3N2v Virus. PLoS Med 10(3): e1001399. doi:10.1371/journal.pmed.1001399

Related Stories

CDC preparing vaccine for new swine flu

August 4, 2012
(HealthDay) -- Only 29 human cases of a new strain of "swine" flu have been identified in two years, but the U.S. Centers for Disease Control and Prevention is making sure it's prepared should the H3N2 strain become more ...

Recent study suggests bats are reservoir for ebola virus in Bangladesh

January 16, 2013
EcoHealth Alliance, a nonprofit organization that focuses on local conservation and global health issues, released new research on Ebola virus in fruit bats in the peer reviewed journal, Emerging Infectious Diseases, a monthly ...

Did wild birds cause the 2010 deadly West Nile virus outbreak in Greece?

November 11, 2012
In 2010, 35 people in Greece died from a West Nile virus (WNV) outbreak, with a further 262 laboratory-confirmed human cases. A new article published in BioMedCentral's open access journal Virology Journal examines whether ...

Recommended for you

New study offers insights on genetic indicators of COPD risk

January 16, 2018
Researchers have discovered that genetic variations in the anatomy of the lungs could serve as indicators to help identify people who have low, but stable, lung function early in life, and those who are particularly at risk ...

Previous influenza virus exposures enhance susceptibility in another influenza pandemic

January 16, 2018
While past exposure to influenza A viruses often builds immunity to similar, and sometimes different, strains of the virus, Canadian researchers are calling for more attention to exceptions to that rule.

Don't hold your nose and close your mouth when you sneeze, doctors warn

January 15, 2018
Pinching your nose while clamping your mouth shut to contain a forceful sneeze isn't a good idea, warn doctors in the journal BMJ Case Reports.

New antifungal provides hope in fight against superbugs

January 12, 2018
Microscopic yeast have been wreaking havoc in hospitals around the world—creeping into catheters, ventilator tubes, and IV lines—and causing deadly invasive infection. One culprit species, Candida auris, is resistant ...

Dengue takes low and slow approach to replication

January 11, 2018
A new study reveals how dengue virus manages to reproduce itself in an infected person without triggering the body's normal defenses. Duke researchers report that dengue pulls off this hoax by co-opting a specialized structure ...

Different strains of same bacteria trigger widely varying immune responses

January 11, 2018
Genetic differences between different strains of the same pathogenic bacterial species appear to result in widely varying immune system responses, according to new research published in PLOS Pathogens.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.