In November 2000, Wildlife Conservation Society personnel transferred 499 Kihansi Spray Toads from the Kihansi Gorge to the Bronx and Detroit zoos, thus establishing the captive population of the Kihansi Spray Toad in US zoos. Although the founding population in the US zoos declined initially due to a lungworm, this was successfully treated, and by July 2002 the captive population of the Kihansi Spray Toad was 580. However due to limited space and resources to manage the growing population, a decision was made to reduce the size of the captive population in the Bronx and Detroit zoos by transferring animals to other zoos and by altering the misting schedule within the cages. Following the collapse of the Kihansi Spray Toad population in the Kihansi Gorge in June 2003, there was an urgency to build up the captive population in the US zoos. Between 2002 and early 2004, the captive population in US zoos continued to decline, and by March 2004 the captive population was 71. To prevent a possible global extinction of the Kihansi Spray Toad, an attempt was made to establish a cell line, which failed. However, as a result of a refinement of the husbandry protocols for the Kihansi Spray Toad, the captive population after March 2004 slowly began to recover, and by late 2007 the captive population was rapidly expanding. By 2010 the captive population of the Kihansi Spray Toad in the Toledo and Bronx zoo was >6400, one of the largest captive populations for any extinct-in-the-wild species worldwide.