Featured Research

from universities, journals, and other organizations

Environment influences ability of bacterium to block malaria transmission

Date:
February 17, 2014
Source:
Penn State
Summary:
The environment significantly influences whether or not a certain bacterium will block mosquitoes from transmitting malaria, according to researchers. The scientists divided two types of mosquitoes into an uninfected control group and a group infected with Wolbachia. Next, the team raised all groups of mosquitoes in incubators set to different experimental temperatures -- 68, 72, 75, 79 and 82 degrees Fahrenheit. At 82 degrees Fahrenheit, Wolbachia reduced the number of mosquitoes infected by malaria parasites and the number of malaria parasites within each mosquito. At 75 degrees, Wolbachia had no effect on prevalence of malaria parasites. At 68 degrees Fahrenheit, Wolbachia had no effect on prevalence of parasites.

Oocyst -- non-infectious stage of malaria -- of Plasmodium yoelii (rodent malaria) attach to the wall of a mosquito midgut.
Credit: Krijn Paaijmans, Universitat de Barcelona

The environment significantly influences whether or not a certain bacterium will block mosquitoes from transmitting malaria, according to researchers at Penn State. "Bacteria in the genus Wolbachia represent a promising new tool for controlling malaria due to their demonstrated ability to block the development of the pathogen within Anopheles mosquitoes -- the mosquitoes that are responsible for the transmission of malaria parasites in many parts of the world," said Courtney Murdock, postdoctoral researcher, Center for Infectious Disease Dynamics and Department of Entomology, Penn State. "However, much of the work on the Wolbachia-malaria interaction has been conducted under highly simplified laboratory conditions. In this study, we investigated the ability of Wolbachia to block transmission of malaria -- Plasmodium -- parasites across variable environmental conditions, which are more reflective of conditions in the field."

Related Articles


The researchers used a species of malaria parasite -- Plasmodium yoelii -- that affects rodents and the mosquito Anopheles stephensi as a model system to investigate whether Wolbachia would block the ability of the malaria parasite to infect the mosquitoes. The scientists divided the mosquitoes into an uninfected control group and a group infected with Wolbachia. Next, the team raised all groups of mosquitoes in incubators set to different experimental temperatures -- 68, 72, 75, 79 and 82 degrees Fahrenheit.

The scientists found that at 82 degrees Fahrenheit, Wolbachia reduced the number of mosquitoes infected by malaria parasites, the number of malaria parasites within each mosquito and the intensity of oocysts -- non-infectious cysts created by malaria parasites that occur on the outer lining of a mosquito's midgut. At 75 degrees Fahrenheit, Wolbachia had no effect on prevalence of malaria parasites, but increased oocyst intensity. At 68 degrees Fahrenheit, Wolbachia had no effect on prevalence of parasites or intensity of oocysts.

In addition, the team identified a previously undiscovered effect of Wolbachia. Infection with the bacterium reduced the development of sporozoites across all temperatures, suggesting that Wolbachia and malaria parasites may compete for similar hosts.

"Typically, the more oocysts a mosquito has on its midgut, the more sporozoites it produces," Murdock said. "So, depending on the environmental temperature, Wolbachia either reduced, enhanced or had no effect on the number of oocysts. At 75 degrees Fahrenheit, Wolbachia-infected mosquitos had three times the numbers of oocysts relative to uninfected mosquitoes. Thus, we would predict these mosquitoes to produce more sporozoites. But instead we see that this is not the case, and that is because Wolbachia infection significantly reduces the number of sporozoites produced per oocyst regardless of the environmental temperature. This effect counteracts the enhancement we see at 75 degrees Fahrenheit. How the influence of Wolbachia on parasite establishment and the production of sporozoites under different temperatures plays out to ultimately affect transmission remains to be determined."

The researchers published their results in a recent issue of Nature Scientific Reports.

According to Murdock, the team's results demonstrate that the transmission-blocking ability of Wolbachia is significantly influenced by the environment.

"These results suggest that the development of this promising control technology requires an improved understanding of how mosquitoes, Wolbachia and malaria parasites will interact in diverse transmission settings," she said. "The worst-case scenario is not whether this technology will be ineffective under particular environmental conditions, but whether or not there is a possibility that certain environments will actually enhance malaria transmission by Wolbachia."

The researchers plan to duplicate their experiment using a species of malaria parasite that affects humans to determine whether or not the temperature effects they observed in the mouse model system also will be observed in a human system. The team plans to explore the effects of additional environmental variation -- such as daily temperature fluctuation and differential access to food resources in the mosquito larval and adult environments -- on the transmission-blocking ability of Wolbachia.


Story Source:

The above story is based on materials provided by Penn State. Note: Materials may be edited for content and length.


Journal Reference:

  1. Courtney C. Murdock, Simon Blanford, Grant L. Hughes, Jason L. Rasgon, Matthew B. Thomas. Temperature alters Plasmodium blocking by Wolbachia. Scientific Reports, 2014; 4 DOI: 10.1038/srep03932

Cite This Page:

Penn State. "Environment influences ability of bacterium to block malaria transmission." ScienceDaily. ScienceDaily, 17 February 2014. <www.sciencedaily.com/releases/2014/02/140217085925.htm>.
Penn State. (2014, February 17). Environment influences ability of bacterium to block malaria transmission. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2014/02/140217085925.htm
Penn State. "Environment influences ability of bacterium to block malaria transmission." ScienceDaily. www.sciencedaily.com/releases/2014/02/140217085925.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Best Tips to Curb Holiday Carbs

The Best Tips to Curb Holiday Carbs

Buzz60 (Dec. 19, 2014) It's hard to resist those delicious but fattening carbs we all crave during the winter months, but there are some ways to stay satisfied without consuming the extra calories. Vanessa Freeman (@VanessaFreeTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Sierra Leone Bikers Spread the Message to Fight Ebola

Sierra Leone Bikers Spread the Message to Fight Ebola

AFP (Dec. 19, 2014) More than 100 motorcyclists hit the road to spread awareness messages about Ebola. Nearly 7,000 people have now died from the virus, almost all of them in west Africa, according to the World Health Organization. Video provided by AFP
Powered by NewsLook.com
Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
The Best Protein-Filled Foods to Energize You for the New Year

The Best Protein-Filled Foods to Energize You for the New Year

Buzz60 (Dec. 19, 2014) The new year is coming and nothing will energize you more for 2015 than protein-filled foods. Fitness and nutrition expert John Basedow (@JohnBasedow) gives his favorite high protein foods that will help you build muscle, lose fat and have endless energy. Video provided by Buzz60
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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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