molecular microbiology

New mouse virus may help scientists better understand cruise ship epidemics

A close relative of a common little-understood human virus that causes an estimated 23 million episodes of intestinal illness, 50,000 hospitalizations and 300 deaths each year has been discovered in mice. The finding by scientists at Washington University School of Medicine in St. Louis is reported in the March 7 issue of the journal Science. Discovery of the new virus, known as murine norovirus 1 (MNV-1), may lead to a better understanding of its disease-causing cousins known as Norwalk viruses, or human noroviruses (HNVs). HNVs cause 90 percent of epidemic viral gastroenteritis worldwide, including those that sweep through cruise ships, nursing homes and military encampments causing debilitating diarrhea and vomiting.

Antibodies critical for fighting West Nile Virus infection

Researchers have found that immune cells called B cells and the antibodies they produce play a critical early role in defending the body against West Nile Virus. The results are published in the February issue of the Journal of Virology. Mice that lacked B cells and antibodies were completely unable to combat the virus. They developed serious brain and spinal-cord infection and ultimately died.

Scientists Discover How to Grow Cells That Suppress Immune Responses

Researchers have discovered how to grow a little-understood type of human immune cell. The cells, known as T-regulatory cells type 1 (Tr1), are thought to turn off unnecessary immune reactions and to block the action of immune cells that otherwise would attack the body and cause dangerous inflammation. The findings are reported in the Jan. 23 issue of the journal Nature.

Researchers decipher cause of parasite’s worldwide spread

Research reveals that a unique combination of genes inherited less than 10,000 years ago allows the parasite responsible for toxoplasmosis to infect virtually all warm-blooded animals. Parasite life cycles are complex and thought to develop over long periods with their hosts. This study reveals that parasites sometimes adapt rapidly to new hosts, indicating that host-parasite relationships may not always represent stable, long-term associations.

Researchers Decipher Cause of Parasite’s Worldwide Spread

Research at Washington University School of Medicine in St. Louis reveals that a unique combination of genes inherited less than 10,000 years ago allows the parasite responsible for toxoplasmosis to infect virtually all warm-blooded animals. Parasite life cycles are complex and thought to develop over long periods with their hosts. This study reveals that parasites sometimes adapt rapidly to new hosts, indicating that host-parasite relationships may not always represent stable, long-term associations.

Satellite Could Help Predict Hantaviral Transmission Risk

Researchers report that satellite imagery could be used to determine areas at high-risk for exposure to Sin Nombre virus (SNV), a rodent-born disease that causes the often fatal hantaviral pulmonary syndrome (HPS) in humans. According to the researchers, satellite imaging detects the distinct environmental conditions that may serve as a refuge for the disease-carrying deer mice. Higher populations of infected deer mice increase the risk of HPS to humans.

Firefly Light Illuminates Course of Herpes Infection in Mice

Researchers are using a herpes virus that produces a firefly enzyme to illuminate the virus’s course of infection in mice and to help monitor the infection’s response to therapy. “This study demonstrates the feasibility of monitoring microbial infections in living animals in real time,” says study leader David A. Leib. “The technique enables us to follow an infection over time as it progresses and resolves, and we can do this repeatedly using the same animal.”