Because of these facts, infections caused by S. iniae in humans and tilapia will be discussed in some detail, as follows.
Tilapia spp. are common food fish reared in aquacultural/aquaponic settings. It seems that one of the most serious diseases with which producers may be faced in the rearing of tilapia is infection by S. iniae, a β-hemolytic bacterial species that was first reported in 1976 as the cause of ‘golf ball disease’ in Amazon freshwater dolphins (Inia geoffrensis) housed in aquaria in the USA. The first streptococcal infection in fish was reported from rainbow trout in Japan, and in tilapia in 1970. Outbreaks of this disease in tilapia were reported later from Japan in 1981, Taiwan in 1985, Israel in 1986, and the USA and Saudi Arabia in 1992. The species was renamed S. shiloi in Israel in 1986, but following taxonomic validation in 1995, the name S. iniae was retained because it was published before S. shiloi (George, 1998). Worldwide, streptococcal infections have been reported from about 22 species of fish. The most seriously affected species include yellowtail (Seriola quinqueradiata), eel (Anguilla spp.?), tilapia, striped bass (M. saxitalis), rainbow trout and turbot (Scophthalmus
maximus). The countries in which fish are most affected by this disease include Japan, Israel, the USA, South Africa, Australia and Spain (George, 1998). Infection by S. iniae in humans was first recorded in Texas, USA in 1991 (George, 1998), and in Ottawa, Ontario in 1994 (Weinstein et al, 1996). In the initial report from Ontario, S. iniae was isolated from four individuals who had a history of preparing fresh, whole aquaculturally-reared fish purchased locally. Three of these individuals had a history of injury to their hands during preparation of these fish. While she was preparing tilapia, one individual punctured her hand with a bone, the second had lacerated the skin over her finger with a knife that had just been used to cut and clean an unidentified freshwater fish, and a third punctured her finger with the dorsal fin of a tilapia she was scaling. The period from injury to the onset of symptoms ranged from 16-48 hours. At the time of hospitalization, these patients had fever and cellulitis (inflammation of the connective tissues beneath the skin), with spread of the infection above the point
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