Biomphalaria glabrata (Say, 1818) as a paratenic host of Angiostrongylus vasorum (Baillet,1866) Kamensky, 1905

Angiostrongylus vasorum parasitizes the pulmonary arteries and heart of dogs (definitive hosts - DHs). Various mollusk species act as intermediate hosts (IHs), becoming infected through ingestion and/or penetration of first-stage larvae (L1), which subsequently develop into second-stage larvae (L2) and then third-stage larvae (L3), the latter being infective to DHs. Additionally, paratenic hosts (PHs), such as frogs, chickens, and rats, can harbor L3. This study aimed to assess whether Biomphalaria glabrata could function as a PH for A. vasorum, identifying potential larval penetration routes, migratory routes, and histological alterations at different time points post-infection. L3 larvae were recovered from B. glabrata mollusks 30 days after exposure to 1000 L1 of A. vasorum, using the Baermann technique. The recovered L3 were used to infect B. glabrata, with the number of 100 L3+ (L3 obtained from mollusks previously infected with 100 L3). Viable and motile L3+ of A. vasorum were detected within mollusk tissues, demonstrating their permissiveness to L3+ infection. The other infected mollusks were fixed in 10% formalin for histological analysis, revealing the presence of larvae, with a tendency in the cephalopodal region. Regarding the viability of L3+, two mixed-breed dogs were fed canine pâté containing L3+, and L1 larvae were detected in their feces. This study demonstrates, for the first time, the potential of B. glabrata to function as a PH in the A. vasorum cycle.