Chikungunya virus spreads through French Antilles Franca has declared a major epidemic of the chikungunya virus in its overseas territory of Martinique in the French Antilles. The mosquito-borne disease first appeared in December and has steadily increased to hit 5,000 new cases per week. And with the rainy season arriving, health authoritis fear that the virus, which causes acute pain in joints and extremities, could continue to spread. IMAGES AND SOUNDBITES.