Strategic Control of Non-Typhoidal Salmonellosis in Poultry Farms
Swagatika Priyadarsini 1, Aditya Agrawal 1, Sriti Pandey 1, Nikhil K.C. 1, Anil Kumar Singh 1, Manoj Kumar Ahirwar 1
- College of Veterinary Science and Animal Husbandry, Rewa (M.P.)
Introduction
Salmonella is a Gram-negative bacterium of zoonotic importance. This genus has two species- S. enterica and S.bongori, and the former species has been categorized into seven subspecies and further into approximately 2500 serovars. Among which Salmonella enterica subspecies enterica serovar Typhimurium or S. Typhimurium (ST) is one of the major causative agents of non-typhoidal salmonellosis (NTS) in humans. This pathogen can infect a wide range of hosts including animals, reptiles as well as birds. Therefore, both intra and interspecies transmission has been found in this case. Besides, S. Enteritidis is also an important causative agent of NTS in poultry.
Sources of infection in poultry farms
Various risk factors involved for the high incidence and prolonged persistence of Salmonellosis are higher stocking density, larger farms (especially caged housing system) and production stress.Poultry can acquireinfection by two different routes: (a) horizontal (from the surrounding flock) and (b) vertical (from mother to progeny). Contaminated feed, water, litter, equipments, utensils, vehicle, clothing, newly introduced stock and infected workers are the sources in the case of horizontal transmission while vertical transmission occurs especially through eggs. Rodents and insects can also act as reservoir of ST for poultry. Consumption of contaminated meat and eggs by human beings will cause infection in the latter and thus, they are banned for sale and export. According to reports, NTS can be the cause for losing 33 million lives per year globally as it is one of the four key causes of diarrhoea in human beings. Recently, globalization has led to an increase in international travel and trade of livestock products, thereby bringingmodernized revolutions to the poultry industries. But due to occurrence of Salmonella outbreaks in farms, the producer has to bear a huge financial loss.Being an important public health problem, NTS calls for an emergency to control its outbreaks in poultry farms.
Control Measures
Humans show the symptoms of self-limiting gastroenteritis, while animals remain as persistent carriers or reservoir hosts due to subclinical infection without showing any visible symptoms. This is the reason why it is difficult to detect the non-typhoidal salmonellosis in a flock or herd unless a suitable bacteriological examination or routine sampling has been carried out. The knowledge of poultry producers about hazard analysis and critical control points (HACCP) measures, awareness on disease transmission and risk factors, attitude towards implementation of hygienic practices are the keys to raise Salmonella-free birds.
Control measures have to be implemented strictly at the farm premises to curtail the infections which are discussed below:
- Strict maintenance of biosecurity measures at access points
- Introducing healthy flock
- Restricted access to the farm premises
- Provision of disinfectants at the entry gate for vehicles
- Disinfectant footbath at the entry points of poultry houses
- Provision of washing and changing room facilities for workers
- Training the workers for safe practices
- Protective clothing for visitors
- Routine cleaning of farm premises, feeders, waterers and other equipments
- All in-all out system reduces the chances of persistence infection
- Cleaning, disinfection and fumigation of the houses after clearing off the flock and before introducing a new flock
- Use of heat-treated pelleted feed
- Restricted use of antibiotics in feed
- Restrict the access of rodents and insects
Lights, heaters, cracks in the floor etc. are often missed while implementing sanitation in the farm.
What if Salmonella is detected in flocks?
- Identify the source of infection.
- Litter and other farm wastes should be safely disposed in a pit away from the production houses.
- Poultry house should immediately be vacated and fumigated
- Equipments should be cleaned and disinfected
- Further bacteriological examination should be carried out before introducing the new flock
Conclusion
Non typhoidal salmonellosis is a zoonotic disease of public health concern which is transmitted to humans from animals and birds either via direct or indirect contact. The infection goes undiagnosed in case of animals due to subclinical infection, and laboratory diagnosis becomes non-feasible in resource limited countries. Additionally, vaccine against NTS is not yet available for poultry in India. Therefore, it is crucial to control the infection at production level so as to break the chain of transmission between humans and poultry. So, some important hygienic practicesalong with biosecurity measures must be implemented in order to prevent the incidence of NTS as well its future outbreaks at farm level.
https://www.pashudhanpraharee.com/salmonella-infection-in-poultry/
https://bmcvetres.biomedcentral.com/articles/10.1186/s12917-018-1539-4
