Thirteen drug companies, the governments of the United States, Britain and the United Arab Emirates, the World Bank, the Bill and Melinda Gates Foundation, the Lions Club and other smaller charitable organizations on Monday announced a joint effort to tackle 10 neglected tropical diseases in a coordinated fashion.

Malaria deaths have fallen by more than 25 percent in the last decade, thanks to a coordinated attack on the disease, but that progress remains fragile, the World Health Organization announced this month.

About 655,000 victims — mostly children — died of malaria in 2010, the report estimated. A decade ago, estimates were closer to a million, though the counting was shakier.

A four-year test of drugs to treat a widespread parasitic disease called kala azar was announced on Monday by the governments of India and Bangladesh, Doctors Without Borders, the Drugs for Neglected Diseases Initiative and other groups.

Kala azar, also known as visceral leishmaniasis, is transmitted by the bite of sand flies smaller than mosquitoes. On the skin, it causes cratered sores; dozens of the first American troops in Iraq in 2003 suffered from it and ruefully nicknamed it the “Baghdad boil.”

Populations on the run during disasters can be tracked by cellphone signals, which could help guide life-saving aid to the right places, a new study has concluded.

For the study, which appeared last week in the journal PLoS Medicine, researchers from the Karolinska Institute in Stockholm and Columbia University formulated their idea after the 2010 earthquake in Haiti, and then tried it out in practice during the cholera epidemic that began there 10 months later.

Gruesome details of American-run venereal disease experiments on Guatemalan prisoners, soldiers and mental patients in the years after World War II were revealed this week during hearings before a White House bioethics panel investigating the study’s sordid history.

A Times article on April 27, 1947, prompted Dr. John C. Cutler to order stricter secrecy about his work, according to Amy Gutmann, the chairwoman of the bioethics panel.

Cholera outbreaks seem to be on the increase, but a new study has found they cannot be explained by global warming.

A bigger factor may be the cycle of droughts and floods along big rivers, according to Tufts University scientists who published a study in The American Journal of Tropical Medicine and Hygiene this month.

Cholera is caused by a bacterium, Vibrio cholerae, whose toxins triggers severe diarrhea when it gets into drinking water.

The first payments were made Thursday to Nigerian families who lost children during a 1996 trial of an experimental meningitis drug, and Pfizer, which had tested the drug, a new antibiotic, said it was “pleased” that payments were finally being made under a settlement reached two years ago.

Despite years of great progress in treating AIDS, the number of new infections with the virus that causes it has remained stubbornly around 50,000 a year in the United States for a decade, according to new figures released on Wednesday by federal officials.

The American epidemic is still concentrated primarily in gay men, and is growing rapidly worse among young black gay men.

Worm infestations, food parasites, Chagas disease, sand fly-transmitted infections and other neglected tropical diseases usually found in Africa and Asia are turning up more often in Europe, according to a new study.

The study, a compendium of dozens of case reports from 1999 to 2010, was published last month in The International Journal of Infectious Diseases by scientists from the Sabin Vaccine Institute and Georgetown University. The problems were worst in Eastern Europe, Turkey, former Soviet states and the Balkans, and weak economies and migratory populations were blamed.

As of July 15, one more country was declared free of the guinea worm: Sudan.

But it was a hollow victory. That was the date Sudan split in two and South Sudan became the world