Using Examinations of Young Black-headed Gulls (larus Ridibvndus) for the Detection of Salmonellae in the Environment

Literak 1., A. Cizek, M. Honza: Using Examinations of Young Black-headed C,ulls (LaTUS ridibundus) for the Detection of Salmonellae in the Environment. Acta vet. Bmo, 61, 1992: 141-146. During June 1991, cloacal smears from nestlings and chicks of black-headed gull (LaTUS ridibundus) of the nesting colonies in the middle reservoir of the water system Nove MIYnY (Breclav district) were examined for the presence 'of salmonellae. On 13 June 1991, 96 yo ng gulls were examined and salmonellae were found in 20 gulls (i. e. 20.83 %), the serotypes being Salmonella typhimurium and S. derby. On 25 June 1991, 171 juvenile gulls were examined and salmonellae were found in 63, i. e. 36.84 % (S. typhimurium, S. enteritidis, S. agona, S. montevideo, S. derby, S. hadar, S. infantis and S. abony. On 16 May 1991, 79 eggs of black-headed gulls from the same colony were examined and no salmonellae were found. It was proved that the water flowing into the reservoir from the river Jihlava and river Svratka in June 1991 was contaminated with salmonellae (i. e. S. ~vphimurium, S. montevideo). Examinations of the juvenile black-headed gulls can be used for the detection of the occurrence of salmonellae in the water. Salmonellae, black-headed gull (Larus ridibundus), eggs, nestlings, chicks, water Analyses of the occurrence of epidemiological and epizootological alimentary infections and intoxication have shown that the situation has considerably changed over the recent 10 years. In the Czech Republic, the incidence of salmonelloses in the human and farm animal populations has increased rapidly, Salmonella enteritidis being the main source of epidemics (Dedicova et al. 1990; Sramkova et al. 1991). The main source of salmonellae is the intestinal tract of sick people and animals. The salmonellae there find favourable conditions for reproduction and through the faeces they get out into the environment. Due to their tenacity and rapid adaptability they find convenient living conditions, particularly in biological refuse. Consequently, they can be found in sewage water from municipal agglomerations, from slaughter-houses, from farm buildings, and also in surface waters (Reilly et al. 1981; Johnston et al. 1986; Kominkova and Blatny 1987). We tried to find out how the contamination of surface water would affect the incidence of salmonellae in populations of wild birds. The black-headed gulls (Laruf ridibundus) were chosen as a model species because they are very numerous, partly synantrophic, and theyare in immediate contact with the water. In Czechoslovakia, Sery and Strauss (1957) drew attention to the incidence of salmonelloses in a colony of black-headed gulls. They isolated S. typhimurium in 77 % of clinically ill and dead gulls. Literak and Kraml (1985) examined cloacal smears from 23 flying black-headed gulls of the Hermanicky pond near Ostrava. In one case they isolated S. typhimurium. Cizek (1990) dealt with the incidence of salmonellae in black-headed gulls, he examined 502 birds from various localities and he isolated 8 serotypes of salmonellae in 12.5 %.