News Scan for Aug 22, 2013

Filariasis prevention, control
;
Ameba drug now available
;
Promising Ebola drug
;
Cholera in Cuba

Antiparasitic agent, bed nets could halt filariasis

Diethycarbamazine (DEC) has become the first medication prequalified by the World Health Organization (WHO) for treatment of a neglected tropical disease (NTD), namely lymphatic filariasis, the WHO announced today. The drug's Japanese manufacturer, Eisai Co. Ltd., has committed to donating 2.2 billion tablets over a 6-year period.

The disease, also known as elephantiasis, is an NTD that currently affects more than 120 million people in the tropics, and can cause disability and disfigurement, says the WHO. Affecting many of the world's most impoverished people, the disease occurs when filarial parasites in their larval stage are transmitted through mosquito bites. The larvae migrate to the lymphatic vessels, where they develop into adult worms.

About 54% of the people infected live in Southeast Asia and 30% in Africa, says the WHO. About 1.4 billion people are at risk.

DEC, given in combination with albendazole or ivermectin, clears microfilariae from the bloodstream. At least five rounds of treatment may be needed.
Aug 20 WHO notice

In related news, a report in today's issue of the New England Journal of Medicine says that insecticide-treated bed nets are highly effective in preventing filariasis and that this low-cost intervention should be expanded along with medication-based preventive efforts globally.

The authors measured transmission of lymphatic filariasis in five villages in Papua New Guinea before and after nationwide distribution of treated bed nets in 2009. The villagers had been part of a drug-intervention effort from 1994 through 1998 as well. After the drug intervention, the rate of disease dropped dramatically, but the effect was short-lived, in part because even though the parasites were cleared from humans, they remained in mosquitoes.

Use of the treated bed nets, the authors discovered profoundly affected the vector population and thus transmission of the disease. The authors said the nets block female mosquitoes from ingesting human blood, which is required for egg laying and reproduction. In addition, the females' life span was decreased, meaning they did not live long enough for the filariasis parasite to become infective. Finally, the mosquitoes' biting behavior was affected; with nighttime net use, the insects tended to bite during the day when the intensity of the microfilariae in human blood is at lower levels.
Aug 22 NEJM study
Aug 21 press release from Case Western Reserve University


IND drug available from CDC for ameba infections

The investigational drug miltefonsine is now available for treatment of free-living amebae (FLA) infections from the Centers for Disease Control and Prevention (CDC) under an expanded access investigational new drug (IND) protocol with the Food and Drug Administration (FDA), according to a notice in tomorrow's Mortality Morbidity Weekly Report (MMWR).

The agent has been used to treat leishmaniasis and has shown in vitro activity against FLA infections, which are often fatal, but it has been used in the United States for FLA only on an emergency basis for individual cases. Reports have shown it to be effective against FLA as part of a drug regimen in 26 cases. The drug is generally well tolerated, with gastrointestinal symptoms the most commonly reported adverse effect.

A physician with a patient who has a suspected FLA can consult with an expert at CDC for information and potential access to miltefonsine by calling 770-488-7100.
Aug 23 MMWR notice


In monkeys, Ebola drug given after symptom onset looks promising

An experimental Ebola drug enabled some monkeys to survive the usually deadly Ebola virus when they were treated after the onset of symptoms, according to a report from US Army and industry researchers.

The drug, a cocktail of monoclonal antibodies called MB-003, was previously shown to protect all monkeys when given 1 hour after exposure to the virus, and it protected two thirds of monkeys when given 48 hours after exposure, according to the scientists' report in Science Translational Medicine.

In the new study, the drug was not given until 104 to 120 hours after exposure, when the monkeys showed signs of disease and the infection was confirmed, say the report and a press release from the US Army Medical Research Institute of Infectious Diseases (USAMRIID). Forty-three percent of the monkeys recovered after treatment, whereas all the control monkeys died.

"By requiring both a documentable fever and a positive diagnostic assay result for Ebola infection before initiating treatment in these animals, we were able to use MB-003 as a true therapeutic countermeasure," senior author Gene Olinger, PhD, of USAMRIID said in the press release. "These initial results push the threshold of MB-003 from post-exposure prophylaxis to treating verified illness."

MB-003 was developed through a decade-long collaborative effort by private industry and the US government, according to the release. The drug is produced in a plant-based system by Kentucky Bioprocessing in Owensboro, Ky.

In the next development steps, MB-003 will need more extensive safety testing in animals, followed by safety testing in humans, said Larry Zeitlin, PhD, coauthor of the study and president of Mapp Biopharmaceutical in San Diego.
Aug 21 USAMRIID press release via EurekAlert
Aug 21 Sci Trans Med abstract

 

US warns travelers of cholera risk in Havana

The US government this week warned travelers to Cuba to take health precautions because of reports of cholera cases in Havana, possibly linked to a cholera outbreak in eastern Cuba.

The notice, from the US Interests Section in Havana, said the Pan American Health Organization (PAHO) has issued a notice that cholera is present in Cuba and that travelers have contracted the disease there recently.

Eating or drinking fecally contaminated food or water is the main risk factor, the US notice said. "Unsterilized water, food from street vendors, raw fish dishes (eg, ceviche) and inadequately cooked (eg, steamed) shellfish are common sources of infection," it states.

The notice advises travelers to follow public health recommendations and guidelines to avoid cholera and to monitor the online travel alerts and warnings from the US Department of State's Bureau of Consular Affairs.

The Cuban government has said almost nothing about the recent cholera cases, presumably for fear of frightening tourists away, the Miami Herald reported yesterday. The story said PAHO reported that Venezuela on Aug 9 confirmed two cholera cases in travelers who arrived from Cuba. Italy and Chile also reported cholera in a few travelers who came to those countries from Cuba in recent weeks, the story said.
Aug 20 US warning notice
Aug 21 Miami Herald story

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