Short report: secondary transmission in porcine cysticercosis: description and their potential implications for control sustainability.
Taenia solium taeniasis/cysticercosis is one of few potentially eradicable infectious diseases and is the target of control programs in several countries. The larval stage of this zoonotic cestode invades the human brain and is responsible for most cases of adult-onset epilepsy in the world. The pig is the natural intermediate host, harboring the larvae or cysticerci. Our current understanding of the life cycle implicates humans as the only definitive host and tapeworm carrier (developing taeniasis) and thus the sole source of infective eggs that are responsible for cysticercosis in both human and pigs through oral-fecal transmission. Here we show evidence of an alternative pig-to-pig route of transmission, previously not suspected to exist. In a series of four experiments, naive sentinel pigs were exposed to pigs that had been infected orally with tapeworm segments (containing infective eggs) and moved to a clean environment. Consistently in all four experiments, at least one of the sentinel pigs became seropositive or infected with parasite cysts with much lower cyst burdens than did primarily infected animals. Second-hand transmission of Taenia solium eggs could explain the overdispersed pattern of porcine cysticercosis, with few pigs harboring heavy parasite burdens and many more harboring small numbers of parasites. This route of transmission opens new avenues for consideration with respect to control strategies.
Gonzalez
Armando E
AE
School of Veterinary Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. emico@terra.com.pe
López-Urbina
Teresa
T
Tsang
Byron Y
BY
Gavidia
César M
CM
Garcia
Héctor H
HH
Silva
María E
ME
Ramos
Daphne D
DD
Manzanedo
Rafael
R
Sánchez-Hidalgo
Lelia
L
Gilman
Robert H
RH
Tsang
Victor C W
VC
D000818:Animals; D003551:Cysticercosis / Q000635:transmission / Q000662:veterinary*; D005260:Female; D018445:Infectious Disease Transmission, Vertical; D013552:Swine; D013553:Swine Diseases / Q000635:transmission*