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Bacteria of the genus Salmonella can infect humans and warm and cold blooded animals. Some are host-specific, such as those that cause fowl typhoid and pullorum disease. However, most do not have a specific host and can cause foodborne infection in humans, and food of animal origin is the main source.
But there is still a lot of confusion in the market involving the concepts, causes and consequences in regard to avian salmonellosis. This content comes, then, to clarify the main differences between Pullorum disease, fowl typhoid and avian paratyphoid. We invite salmonella expert Dr. Angelo Berchieri Junior to bring extremely relevant information and help us compose the following infographics.
He is a full professor in Ornithopathology at the Department of Pathology, Reproduction and Single Health at the Faculty of Agrarian and Veterinary Sciences (FCAV) at Universidade Estadual Paulista (Unesp), Jaboticabal campus.
But first, it is worth explaining a little more about the species of bacteria.
The genus Salmonella, with more than 2600 serotypes, is composed of two species: S. bongori, which contains few serotypes and S. enterica composed of 6 subspecies, including subspecies enterica, which contains most serotypes of interest in animal and public health, including the Salmonella Gallinarum serovars (Gallinarum and Pullorum biovars ), with an impact on animal health — in addition to Enteritidis, Typhimurium, Heidelberg, Mbandaka, Infantis, Agona, Senftenberg, etc., which pose a risk to public health.
In poultry farming, birds can present three salmonella-related conditions:
1st) Pullorum Disease: caused by Salmonella enterica subspecies enterica serovar Gallinarum biovar Pullorum.
2nd) Fowl typhoid: caused by Salmonella enterica subspecies enterica serovar Gallinarum biovar Gallinarum.
3rd) Avian paratyphoid: infection caused by other serovars, which may or may not cause disease in poultry.
Check out the main differences in the infographics:
The importance of preventing salmonellosis
Fowl typhoid and Pullorum disease are diseases that can bring great harm to poultry farmers. While the first is more common in adult birds, with a high mortality rate, the second is more frequent in birds in the first weeks of life, so much so that it is also called fatal chick septicemia.
These are diseases that can be devastating to business. For fowl typhoid, antibiotic treatment temporarily reduces mortality but does not eliminate the bacteria from the flock. In addition to not solving the problem, the use of antibiotics can poison the chickens and make it difficult to carry out microbiological tests to isolate the bacteria.
For both fowl typhoid and pullorum disease, treatment for flocks of breeders is not recommended: the National Avian Health Plan (PNSA) in Brazil recommends the elimination of breeding flocks carrying Salmonella Gallinarum or Salmonella Pullorum.
Control strategy for avian salmonellosis
The control strategy for avian salmonellosis is based on investing in biosecurity. Sanitary management is the main means of preventing infectious diseases. Initially, it is necessary to respect the PNSA. Knowing epidemiology is another essential aspect. Thus, to prevent Pullorum disease it is essential to avoid infection of breeding flocks.
To prevent fowl typhoid, the conduct is different. The main concern is with outbreaks of the disease in the region and the mechanisms of dissemination, for example, carcasses of dead animals, humans and vehicles.
As for avian paratyphoid, the situation is more complex. There are several ways of introducing these salmonellae into farms, the vertical route being the most worrying, followed by feed and its components. Because they are excreted in the feces, they are easily disseminated in the environment, making their control difficult.
Sanitary management performed rigorously manages to minimize the introduction and spread of salmonella in poultry farms. Additional measures can be taken to complement it. Included here are the offer of acidifying products in feed and drinking water, products that promote the installation and multiplication of a healthy microbiota that helps in the maintenance and health of the gastrointestinal tract, at the beginning of life or after antimicrobial therapies for prolonged periods.
Long-life poultry farms for laying of table eggs are found in regions with a high density of chickens of various strains, ages and sanitary management. Under these conditions, vaccine programs contribute to the reduction of the fowl typhoid agent or some paratyphoid salmonella. Therefore, given the intensive rearing system, with high density and for a long period, and due to the fact that it is not known when the infection of the chickens will occur, vaccination can be considered a good strategy.