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DI 91/16

Biological control of mosquitoes portfolio

Inventor: Armelle DELECLUSE et al.

 Description of invention:

Mosquito-borne diseases affect millions of people worldwide each year. Some mosquitoes can transmit diseases such as encephalitis, dengue fever, and malaria to humans. To combat mosquitoes and the potential public health hazards they present, mosquito control agencies around the world spend hundreds of millions of dollars annually.

Unfortunately, some mosquito control substances have proven toxic and destructive to the environment. Pesticide use raises concern about contamination of ground and surface water, as well as health hazards to people and the environment. After the use of pesticides, the immediate number of mosquitoes may drop, but later increases because the predators have also been poisoned, have starved from lack of prey, or have moved on to hunt somewhere else.

In an effort to develop more environmentally responsible methods of mosquito control, numerous scientific teams have been evaluating microbiological control strategies involving mainly Bacillus thuringiensis (Bt) subspecies israelensis (Bti) or Bacillus sphaericus (Bs). Researchers at the Institut Pasteur have developed a number of Bacillus-based products useful for mosquito larvae. Included in this commercially interesting portfolio are the patents highlighted below: 

Key Institut Pasteur Patents

1. US 5,736,513 (filed November 10, 1993 - issued April 7, 1998) and US 6,071,878 (filed December 12, 1997 - issued June 6, 2000) : Non- hemolytic mosquitocidal microorganisms.
Inventors: Armelle DELECLUSE et al.

The patent relates to new compositions useful for killing mosquito larvae. A composition comprising purified mosquitocidal crystals produced by Bacillus thuringiensis israelensis (Bti), where the crystals are devoid of the 28 kiloDalton(kD) hemolytic protein, have mosquitocidal activity, lack hemolytic activity and contain 68, 125 and 135 kD proteins having hemolytic activity, is claimed.
A key advantage of the invention is that the crystals lack non-specific cytolytic activity while still retaining high mosquitocidal activity. By killing mosquitoes and inhibiting the development of their larvae, these polypeptides are useful as biological control against mosquitoes.

2. WO 9606171 (Priority application FR 9410299 filed Aug 25, 1994) - US 6,071,877 (filed May 13, 1997 - issued June 6, 2000) : Polypeptides having a toxic activity against insects of the dipterae family.
Inventors: Armelle DELECLUSE et al.

Pursuing their objective of neutralizing the possible appearance of insects resistant to Bacillus sphaericus and Bacillus thuringiensis israelensis (Bti) toxins, the inventors have continued the search for novel strains exhibiting an activity against mosquitoes. In the present invention, the researchers identified one Bt strain, Bacillus thuringiensis jegathesan 367 as presenting a novel pattern of larvicidal activity and a protein profile different from those of other strains.
The patent relates to new B. thuringiensis jegathesan insecticidal proteins and related DNA, with high activity against dipteran larvae, including mosquito larvae of the species Aedes aegypti, Anopheles stephensi, and Culex pipiens. A key advantage of the larvicidal protein, designated jeg80 (Cry11Ba), is that it is 6-40 times more toxic against mosquitoes (depending on the species of mosquito tested) than the closely related CryIVD toxin of Bacillus thuringiensis. This difference of activity might reflect different modes of action of the two toxins.
This difference might be exploited in the development of new insecticides as the Cry11Ba protein is the most mosquitocidal component ever found.

Potential advantages:

 Harmless to non target organisms and the environment. 
 Alternative to toxins used in current control thereby addressing risk of mosquito resistance against Bacillus thuringiensis israelensis (Bti) and Bacillus sphaericus (Bs) toxins.
 Greater potency against target organisms than toxins currently on the market currently mark toxins.
 Cry11Ba protein is the most mosquitocidal component ever found.


Contact :Vincent Charpentier, Business Development Manager - Office of Technology Transfer
 Institut Pasteur - 28 Rue du Docteur Roux - 75724 Paris Cedex 15 FRANCE
Tel : +33.(0)1.45 68 81 87- Fax : +33.(0) – email :