Paratyphoid and other Salmonella infections

Paratyphoid salmonellae are non-host-specific. The commonly reported species are S. Typhimurium, S. Enteritidis S. Thompson, S. Menston, S. Virchow and S. Haddar. The main sources of infection are contaminated feed or other inanimate objects. Transmission can also occur through infected embryos. These bacteria may cause food poisoning in humans when foodstuffs are contaminated with feces. Eggs from infected hens may also contain salmonellae.

Symptoms and lesions: Newly hatched chicks are mainly affected and clinically this disease cannot be distinguished from pullorum disease. The lesions are also not characteristic. There may be liver necrosis and catarrhal enteritis.

Diagnosis: Isolation and identification of the organism are essential to make a differential diagnosis from pullorum and gallinarum infections.

Prevention and control: In farm management, to keep away from Salmonella infection is the best policy. General approaches for control of salmonellosis include continuous screening and elimination of reactors. This is to be combined with high flock-management standards and hatchery discipline. The birds are to be tested between 16 and 20 weeks. Two consecutive clear tests, one month apart are followed by annually tested negative flock provide the evidence of pullorum free status. Hatching eggs, fresh chicks, replacement lots, feed etc. must be purchased from known salmonella- free sources. Since the usual source of infection is contaminated feed, use of pelleted feed reduces the chance of salmonellosis.