SALMONELLA GALLINARUM IS PART OF WHICH GROUP OF SALMONELLA - TYPHOID OR PARATYPHOID?
SG is part of the Typhoid infections.
WHAT IS THE CAUSATIVE AGENT OF FT? WHAT ARE THE CHARACTERISTICS OF THIS DISEASE?
The causative agent is Salmonella enterica subsespecie enterica serovar Gallinarum biovar Gallinarum. The disease is characterized by being systemic, acute / chronic septicemia and by resulting in high mortality and morbidity, between 40-80% of the flock.
WHAT IS THE MAIN ROUTE OF SG TRANSMISSION / INFECTION?
The fecal-oral route is the main route of SG transmission / infection.
WHAT DIAGNOSTIC METHODS CAN BE USED TO IDENTIFY THE AGENT THAT CAUSES AT?
Bacteriological isolation of the etiologic agent is necessary through aseptically collected samples from infected tissues, preferably the liver and spleen of supposedly infected birds. It is worth mentioning that SG does not grow in the most modern chromogenic culture media (ex: XLD and XLT4) and in tetrathionate, which if used for isolation will lead to a false negative. After isolation, confirmation of the Gallinarum serotype must be carried out using biochemical or molecular techniques. Serological tests (ELISA and rapid whole-blood plate test =Pullorum disease antigen) do not detect Salmonella Gallinarum, they only indicate vaccination or infection by salmonella from group D.
ARE WHITE LAYING HENS RESISTANT TO SG INFECTION?
White laying hens are as infected as red laying hens. However, in general, clinical signs and mortality are less pronounced.
WHAT IS THE GREATEST SUSCEPTIBILITY OF COMMERCIAL BIRDS TO FOWL TYPHOID?
White layers are the most resistant and red layers are the most sensitive. Breeders´ susceptibility is closer to red laying hens.
HOW CAN FOWL TYPHOID BE PREVENTED IN COMMERCIAL FARMS?
Currently, only with active health surveillance, biosecurity and an adequate vaccination program with SG 9R strain live attenuated vaccines.
WHAT IS IMPORTANT TO DO DURING AN SG OUTBREAK TO DECREASE TRANSMISSION?
It is essential to remove birds sick, dying or dead as soon as possible, several times a day and eliminate them technically.
IS IT EFFECTIVE TO TREAT FOWL TYPHOID WITH ANTIBIOTICS?
No, because the infection is not eliminated with the use of antibiotics, only mortality is temporarily reduced.
HOW DOES SG IMMUNITY WORK?
Immunity is given through cellular immune response and, for this, it is essential to use live attenuated vaccines, such as SG 9R.
SHOULD I VACCINATE A HOUSE NEXT TO THE AFFECTED BUILDING WITH FT, EVEN IF THERE IS NO MORTALITY?
In a farm that suffers from a FT outbreak in a house and there is no adequate isolation between neighboring flocks or group of sheds, it is important to vaccinate all birds on the farm, even if they are white laying hens and have no symptoms.
CAN VACCINATION FOR SG BE DONE AFTER TREATMENT WITH ANTIBIOTICS?
Yes, it is possible, but the period of 7 days (ideally 14 days) after the end of the antibiotic medication must be respected to carry out the vaccination, regardless of the vaccination route used.
IS THERE A REVERSAL OF VIRULENCE OF THE SG 9R VACCINE?
The outbreaks that arise are caused by SG field strains. The studies indicate that there is no reversal of the virulence of the SG 9R vaccine. This strain has been used in all countries that suffer from FT for more than 50 years.
WHAT IS THE BEST DESTINATION FOR BIRDS KILLED BY SG?
The best way is to incinerate dead birds and not do the composting, as there is a risk of spreading the infection through insects, mites, domestic and wild animals.
ORGANIC ACIDS ARE EFFECTIVE TO CONTROL SG?
SG is not controlled with the use of organic acids, essential oils, prebiotics or probiotics. These are efficient tools for the paratyphoid infections that colonize the intestine and especially the cecum.
THE COMPETITIVE EXCLUSION (CE) SHOULD BE USED TO CONTROL SG?
The use of CE is very important to control the colonization of the intestine and the cecum by paratyphoid Salmonella and not by SG, since it does not live in the intestines of birds.
SHOULD THE FLOCKS OF POULTRY BREEDERS CONTAMINATED BY SG BE ELIMINATED?
As there is no efficient treatment for SG, to eradicate the problem, it is necessary to summarily eliminate the poultry breeders contaminated by SG.