Featured Research

from universities, journals, and other organizations

Evaluating 'acquired immunity' may improve estimates of infectious disease risk

Date:
May 21, 2014
Source:
Society for Risk Analysis (SRA)
Summary:
A new health study that accounts for "acquired immunity" when evaluating the risk of microbial illness from food or environmental exposures suggests that some current approaches may significantly overestimate their role in causing such illnesses. Immune status is a major factor in susceptibility to foodborne and environmental infectious diseases. By considering both the impact of acquired immunity to a pathogen and the amount of a pathogen to which people are exposed, researchers have developed a novel approach for more accurately assessing the potential health risks of infectious diseases.

A new health study that accounts for "acquired immunity" when evaluating the risk of microbial illness from food or environmental exposures suggests that some current approaches may significantly overestimate their role in causing such illnesses. Immune status is a major factor in susceptibility to foodborne and environmental infectious diseases. By considering both the impact of acquired immunity to a pathogen and the amount of a pathogen to which people are exposed, researchers have developed a novel approach for more accurately assessing the potential health risks of infectious diseases.

A.H. Havelaar and A.N. Swart, from the National Institute for Public Health and the Environment (RIVM) and Utrecht University in the Netherlands evaluated the impacts of various dose-response models on the Dutch population's exposure to C. jejuni, a species of bacteria commonly found in animal feces, food and the environment. Dose-response models help to estimate the risk of human illness caused by differing levels of exposure within a certain timeframe -- in this case exposure to the common pathogen C. jejuni.

In their article -- "Impact of Acquired Immunity and Dose-Dependent Probability of Illness on Quantitative Microbial Risk Assessment," published in Risk Analysis, the journal of the Society for Risk Analysis -- Havelaar and Swart looked at four illustrative scenarios of exposure: (1) low frequency, low dose exposure (recreational water); (2) low frequency, high dose exposure (consumption of raw chicken liver); (3) high frequency, low dose exposure (direct contact with sheep and goats, i.e. farmers); and (4) high frequency, high dose exposure (visits to petting zoos).

Results of their research provided strong evidence that using dose-response models with an acquired immunity component can significantly affect the estimated disease risk of individuals and populations. According to Havelaar and Swart, "The risk [estimated] in immunity models is approximately ten times lower than [in risk estimate] models that do not take immunity into account" for certain scenarios. In most dose-response models, direct animal contact, such as in petting zoos, is the main risk factor for illness caused by C. jejuni, with 64 to 74 percent of the risk attributable to direct contact. However, with dose-response models incorporating acquired immunity, only 26 percent of the risk was attributed to exposure through petting zoo activities -- a much lower probability of disease from exposure to a given source. Differences in the results of the models examined were also dependent on the exposure scenario and exposure frequency. There seems to be improved correspondence with epidemiological estimates of disease incidence. Accounting for immunity could lead to more effectively identifying and managing public health risks from microbes.

This research demonstrates that the model used has an impact on both risk estimations and the attribution of illness to different sources of exposure, which is key to preventing infection and managing disease. By combining acquired immunity and dose-dependence into incidence estimates, the results differ drastically. Since the models were developed in the face of scarcity of data on immune parameters and exposure doses, exact impact on human disease is hard to quantify. Nonetheless, the results are robust and consistent.

Based on this research, the authors urge the public health community to more carefully take acquired immunity into account to improve estimates of the potential impacts of infectious diseases and to assist in preventing and managing them. They also discuss the need for further studies to better characterize and quantify the effects of acquired immunity on intestinal infections.


Story Source:

The above story is based on materials provided by Society for Risk Analysis (SRA). Note: Materials may be edited for content and length.


Journal Reference:

  1. A. H. Havelaar, A. N. Swart. Impact of Acquired Immunity and Dose-Dependent Probability of Illness on Quantitative Microbial Risk Assessment. Risk Analysis, 2014; DOI: 10.1111/risa.12214

Cite This Page:

Society for Risk Analysis (SRA). "Evaluating 'acquired immunity' may improve estimates of infectious disease risk." ScienceDaily. ScienceDaily, 21 May 2014. <www.sciencedaily.com/releases/2014/05/140521133127.htm>.
Society for Risk Analysis (SRA). (2014, May 21). Evaluating 'acquired immunity' may improve estimates of infectious disease risk. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2014/05/140521133127.htm
Society for Risk Analysis (SRA). "Evaluating 'acquired immunity' may improve estimates of infectious disease risk." ScienceDaily. www.sciencedaily.com/releases/2014/05/140521133127.htm (accessed July 25, 2014).

Share This




More Health & Medicine News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

AFP (July 24, 2014) A so-called drugs rehab 'clinic' is closed down in Pakistan after police find scores of ‘patients’ chained up alleging serial abuse. Duration 03:05 Video provided by AFP
Powered by NewsLook.com
Too Few Teens Receiving HPV Vaccination, CDC Says

Too Few Teens Receiving HPV Vaccination, CDC Says

Newsy (July 24, 2014) The Centers for Disease Control and Prevention is blaming doctors for the low number of children being vaccinated for HPV. Video provided by Newsy
Powered by NewsLook.com
New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins