By Ben Hirschler
LONDON (Reuters) - Johnson & Johnson is joining the hunt for drugs to treat dengue fever - the world's fastest-spreading tropical disease - by linking with academic researchers in Belgium and the Wellcome Trust medical charity.
There is currently no drug treatment or vaccine for the mosquito-borne viral disease, which is also called "breakbone fever" because of the severe pain it can cause.
The tie-up between J&J's Janssen unit and researchers at the University of Leuven, who have received backing from Wellcome, will build on the discovery of a series of chemical compounds that are highly potent in preventing the replication of dengue virus.
The compounds, which have yet to be tested in clinical trials, are active against all four types of the virus and have been shown to work in animal tests.
While testing them in humans will take many years, the new alliance marks a vote of confidence in the feasibility of making an effective dengue medicine. J&J already has a proven track record in developing other antiviral medicines, including treatments for HIV and hepatitis C.
The partners said on Thursday that J&J would make an undisclosed upfront payment and milestone payments based upon the achievement of development, regulatory and sales goals.
Experts estimated in April that there may be as many as 390 million dengue infections around the world each year, although not all patients get seriously sick.
Current approaches to treating the condition are focused on alleviating symptoms.
Spread by the Aedes aegypti mosquito, dengue has grown rapidly along with urbanization and globalization because it thrives in tropical mega-cities and is easily spread in goods containing small puddles of water, such as used tires.
Climate change is also making more parts of the planet habitable for the dengue-spreading mosquito.
As a result, half the world's population is now exposed to the disease - mostly in the developing world, but also in parts of southern Europe and the southern United States.
Last year Europe experienced its first sustained transmission of dengue fever since the 1920s with around 2,000 people infected in the Portuguese archipelago of Madeira.
Hopes for an effective dengue vaccine suffered a setback last year when an experimental shot from Sanofi proved less effective than hoped in a mid-stage clinical trial in Thailand.
Further large trials of the vaccine - the most advanced in development - are still continuing and scientists have not given up hope that it may yet have a role to play, while Sanofi is stepping up its production.
(Editing by Mark Potter)