Scientists have identified a specific type of immune cells that they said may cause malaria patients to develop more serious disease, according to a report to be published on Friday in the journal PLoS Pathogen.

These immune cells, known as regulatory T (Treg) cells, switch off the immune system and can allow the parasite to grow uncontrollably.

Magdalena Plebanski from Monash University and colleagues studied 33 malaria-infected adults in the southern lowlands of Papua, Indonesia, and identified elevated levels of Treg cells in the 16 patients with severe malaria.

"The regulatory (Treg) cell subset associated with severe disease in humans expresses a unique combination of surface markers, including TNFRII ... (suppressing) the activation and expansion of effector immune cells, which partake in parasite elimination," Plebanski said.

"Our results indicate that severe malaria is accompanied by the induction of highly suppressive Treg cells that can promote parasite growth, she said, reminding of caution against the induction of these Treg cells when developing effective malaria vaccines.

It is estimated that 500 million people live in areas where there is a risk of getting malaria. The severe disease causes around 1 to 3 million deaths each year.

"Targeting this cell type may lead to new drugs and immunotherapeutics against malaria," Plebanski said, adding that further studies are needed to determine if this new cell may also promote severe forms of other inflammatory diseases. WASHINGTON, April 23 (Xinhua) -- Scientists have finished the genome sequence of cows, which could contribute to better disease resistance and higher quality meat for consumers, according to reports to be published Friday in journal Science.

Scientists discovered the cattle genome contains at least 22,000 genes, 80 percent of which are shared with human beings. They also found that cattle have far more in common genetically with humans than mice or rats, and might make better subjects for studying human health.

"The bovine genome is more similar to that of humans than mice or rats at all levels, from genomic DNA rearrangements to shared genes and identity of their protein sequences" said Evgeny Zdobnov, one of the leading analysts from the project and a researcher at the University of Geneva and the Swiss Institute of Bioinformatics.

Comparisons of the domestic cattle genome sequence to those of the human, dog, mouse, rat, opossum and platypus could reveal new insights about the human genome, scientists said.

They warned that present cattle came from a diverse ancestral population from Africa, Asia and Europe that has undergone a recent rapid decrease in population size, most likely because of domestication.

"Understanding the cattle genome and having the sequence will allow researchers to understand the genetic basis for disease in domestic cattle and could result in healthier production of meat and milk while reducing producers' dependence on antibiotics," U.S. Agriculture Secretary Tom Vilsack said in a statement.

The large-scale undertaking, led by researchers at Baylor College of Medicine and the U.S. Agricultural Research Service, mobilized more than 300 scientists from 25 countries over six years.