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Other Names: Salmonella Infection

Salmonellosis is the name of a collection of diseases caused by infection with the genus Salmonella. There are several different species which each manifest as a specific disease.
  • Arizonosis: Arizonosis is a septicemic disease of young turkeys, sometimes chicks, caused by Salmonella enterica subsp. arizonae (S. arizonae). The disease presents in both acute or chronic form and is characterized by septicemia, neurological signs and blindness.
  • Pullorum disease (PD): Pullorum disease, also referred to commonly as Bacillary White Diarrhea, is an acute systemic disease of young chicks, caused by infection with S. Pullorum. It is mainly a problem for newly hatched chicks, which begin to show clinical signs of infection within a couple weeks upon hatching. Chicks may be seen huddling under heat sources, making continuous faint chirping and peeping noises. These chicks will also develop white chalky droppings that cause them to develop white pasted vents (known commonly as 'pasty butt').
  • Fowl typhoid (FT): Fowl typhoid is an acute or chronic septicemic disease that usually is most significant in growing and adult chickens and turkeys. It is caused by infection with S. Gallinarum. Clinical signs differ depending on the severity of the infection. Infected chickens often will die 5-10 days following when they first develop clinical signs.
  • Paratyphoid (PT) Infection: Paratyphoid (PT) Infection is a common disease of chickens, usually more significant to younger chicks than for adults. It is caused by several different strains of Salmonella spp. The most common being S. Typhimurium and S. Enteritidis.
PD and FT testing has been incorporated into the requirements of the NPIP National Control Program, implemented in the United States to attempt to minimize the circulation of both diseases in flocks.


Salmonella spp are both horizontally and vertically transmitted. They are spread through transovarian transmission from hens to to their offspring, contamination of the environment (soil, bedding, perches, nesting boxes, eggs, waterers, drinkers, etc.), mechanically through flying and biting insects, rodents, wild birds, introduction of new flock members, equipment, vehicle tire tread, clothing, unwashed hands, etc. Many animals, especially poultry and pigs, may be infected with Salmonella but show no signs of clinical illness. They are a significant source of spreading the disease among other flock members and potentially other animals and humans. This is because infected sub clinical carriers may shed the bacteria in large numbers within their feces, either continuously or intermittently, contaminating the environment.


Samples of feed, water, or litter can be collected and tested for the presence of Salmonella. Sterile cotton swabs can be used for isolation. Cotton swabs can be dragged along litter to check for environmental contamination or be used to check breeder nests, laying cages or hatchery machines. There are a wide range of rapid Salmonella detection techniques, including enzyme immunoassay antigen capture assays, DNA probes, and immunofluorescence.

Clinical Signs

Huddling together
Poor growth
Chalky white diarrhea w/ pasted vent
Reduced egg production


  • History
  • Clinical signs
  • Isolation of the bacteria
  • Serology
  • PCR
  • SAT
  • Necropsy

Reported Cases

  • Case 1: Salmonellosis in a Chicks The presence of Salmonella was investigated in transport boxes of newly hatched chicks in the moment they were received in the farms. 1,611 boxes, delivered to 15 farms (one broiler grand-parent farm, four broiler parent farms, two commercial broiler chick farms and seven laying hens farms) were tested. A total of 19 visits to these farms were done, and Salmonella was detected in ten of these visits. Salmonella Heidelberg was detected in boxes in five farms. S. Heidelberg and S. Mbandaka were simultaneously detected in one broiler breeder farm. Salmonella Enteritidis alone, S. Enteritidis and S. Mbandaka and S. Cerro alone were detected in three, one and one laying hens farms, respectively. Ref

  • Case 2: Salmonellosis in a Chickens A Salmonella typhimurium outbreak in 1-to-2-week-old broiler flocks in Mexico is reported. Clinical signs were growth retardation, blindness, twisted necks, and lameness. Gross lesions consisted of hypopyon, panophthalmitis, hepatomegaly with necrotic foci, enlarged spleen, pericarditis, coagulated and unabsorbed yolks, and purulent arthritis. Mortality and cull rates in different flocks ranged from 1.7% to 10.6% during the first two weeks of age. All internal organs, eyes, and hock joints of diseased chickens that were cultured were Salmonella-positive. The bacteria were also isolated from the breeder source flock. Disease was thought to be transmitted through eggs at hatch. Ref

  • Case 3: Salmonellosis in a Chicks Fifty-three carcasses of 2-weeks old pullets were presented at the poultry and fish clinic of the Veterinary Teaching Hospital, University of Jos, Nigeria for investigation. There was persistent mortality despite 5 days medication with 20% Enrofloxacin (Floxinor®). Cumulative mortality within 14 days was 203 birds in a flock of 4,000. Necropsy was done and harvested were subjected to microbial analysis for bacterial isolation, identification and antibiotic susceptibility test while portions of these organs were preserved in 10% formalin for histopathology. Necropsy findings were empty crops, hepatitis with petechial hemorrhages, nephritis, congested and consolidated lungs, peritonitis, congested spleens and mild enteritis. Histologically, there were vacuolation and necrosis of renal tubular epithelia cells and interstitial infiltration with heterophils. Severe disorganization of hepatic cords, infiltration with inflammatory cells and mild necrosis of hepatocytes were observed, while there was severe congestion and diffuse hemorrhages in the lungs. Cellular infiltration within the lamina propria of small intestine with stunting and blunting of the villi were observed. Organism isolated on MacConkey agar was identified as Salmonella Enteritidis. Antibiotic susceptibility test showed the organism to be most susceptible to Streptomycin, which was administered via drinking water at dosage of 40mg/kg with good recovery of the flock. It was concluded that the occurrence of Salmonella Enteritidis infection in this flock might be from the hatchery or via ingestion of contaminated feed and water. Day old chicks should be screened for Salmonella infection and strict biosecurity should be instituted on poultry farms. Ref

  • Case 4: Salmonellosis in a Chicken Salmonella Enteritidis (SE) was isolated from a rooster submitted to CAHFS with digestive tract inflammation. Two weeks earlier, the rooster had been abandoned in a park which also contained other abandoned chickens. A neighbor with chickens, pigeons and pets took in the bird for nursing care after observing it with lethargy, diarrhea and fever. On a separate premise, Salmonella Enteritidis was isolated from seven, 15-day-old chickens submitted from a community farm where 100 of the 300 chickens purchased from a hatchery had died. Ref

  • Case 5: Salmonellosis in a Chickens Salmonella enteritidis was detected in a fecal pool and the livers of three of four pasture raised Cornish cross chicks experiencing increased mortality. Gross postmortem and histology revealed hepaitis and yolk sac infections in four and two birds, respectively, and one chick had brain and lung involvement. Ref

  • Case 6: Salmonellosis in a Chickens A severe outbreak of salmonellosis in commercial brown table egg layers first occurred in Colombia in 2006. From 2008 to 2012, 35 samples collected from commercial layers farms in the states of Cundinamarca, Santander, Bolivar, and San Andres, were positive for Salmonella enterica. Salmonella was isolated from liver and spleen (71.42%), pools of organs (liver, spleen, and ovarian follicles; 25.71%), and drag swabs (2.85%). Serotype was assigned using single nucleotide polymorphisms or DNA microarray hybridization. Sixteen strains of Salmonella Enteritidis, and 13 of Salmonella Gallinarum were identified. Seven strains yielded three unique sequences, and they were designated as UN0038, UN0052, and UN0054 by intergenic sequence ribotyping. These strains were later identified as Salmonella serotypes Isangi, Braenderup, and Yoruba, respectively, by DNA microarray hybridization. The discovery that a common human pathogen (Salmonella Enteritidis) was coisolated from farms with an avian pathogen (Salmonella Gallinarum) in similar commercial brown layer hens and in different regions indicates that it is important to investigate the dynamics of Salmonella infection and determine the serotypes circulating within the same ecologic niche. Ref

  • Case 7: Salmonellosis in a Cockatoo Two fatal cases of Salmonella Typhimurium phage type DT160 infection occurred in Moluccan cockatoos from a zoological collection in Italy. No previous clinical signs were observed in birds before death, except for anorexia and mild diarrhea in one bird. At post mortem, necrotic foci surrounded by a hyperemic halo were observed in lungs, heart, liver, spleen, kidneys, and intestine. Microscopically, heterophils and macrophages with rare lymphocyte infiltration associated with gram-negative, rod-shaped bacteria aggregates were detected in necrotic foci. Bacteriology confirmed the presence of Salmonella Typhimurium phage type DT160 in the tissues of birds. The source of Salmonella Typhimurium in these birds remains unknown, but the authors emphasize the need to better control Salmonella infections in these avian species because they are important zoonotic agents and responsible for disease in animals and humans. This is the first documentation of Salmonella Typhimurium phage type DT160 infection in Moluccan cockatoos. Ref

  • Case 8: Systemic salmonellosis in a Finches Systemic salmonellosis was diagnosed as the cause of death in pine siskins from three counties between November and February. Nine wild pine siskins from Santa Clara, San Mateo and Marin counties were submitted to CAHFS for necropsy. In six of the nine birds Salmonella typhimurium was isolated from various sites; these birds presented with esophagitis, head/neck cellulitis and systemic lesions suggestive of septicemia. Ref

  • Case 9: Salmonellosis in a Pigeon Salmonellosis due to S. Typhimurium was diagnosed in two separate pigeon losses. One loft had increased mortality and the other had a pigeon submitted with neurological signs. The later had pale yellow foci in the cerebral cortex, enlarged cerebellum and cloudy meninges. Both birds had hepatitis and the neurologic bird also had meningoencephalomyelitis, osteomyelitis, otitis interna, pneumonia, splenitis, nephritis and iridocyclitis. Salmonella Typhimurium was isolated from the liver of both birds and brain and intestine of the neurologic one. Ref

  • Case 10: Salmonellosis in a Chicks Salmonella Zega isolated from natural outbreaks that were characterized by high mortality in poultry farms in three Southwestern States of Nigeria was used to inoculate two week-old chicks through different routes in order to determine and compare the clinical signs, pathological and immunohistochemical changes in each route of infection. The birds were divided into 4 groups of 25 each as groups A (orally inoculated), B (intraperitoneally inoculated), C (inoculated per cloaca) and D (uninoculated control). All the birds were inoculated with 0.2ml of 1×108 cfu of the bacteria. Clinical signs were observed and recorded according to the route of infection, and with the days post-infection from day 0 till day 10 post-infection. Two birds from each group were sacrificed every 24h and examined for gross lesions, which were described and scored according to the route of infection and days post-infection. Samples of visceral organs were collected for bacteriology, histopathology and immunohistochemistry. Clinical signs in chicks infected orally and intraperitoneally were weakness, anoraexia lethargy, somnolescence, yellowish diarrhoea observed from 4 days till day 10 post infections. Mild sign of weakness was observed in chickes infected per cloaca, from day 3 to 7. The gross lesions were congestion, oedema and enlargement and necrosis in visceral organs from day 4 to 10 post infection in orally and intraperitoneally infected chicks, but mild vascular changes were observed in chicks infected per cloaca, except in the caecum were lesions of necrosis and infiltration of inflammatory cells were moderate to severe. Microscopic lesions were necrosis of host cells and infiltration by lymphocytes, heterophils and macrophages in multiple organs observed from day 4 to 10 post infection in orally and intraperitoneally infected chicks. Immunoreactions were observed in all the visceral organs examined. Clinical signs, pathological and immunohistochemical findings were mild in chicks infected per cloaca, except caecal lesions. Salmonella Zega isolated from an outbreak in poultry farms in Abeokuta, Nigeria was highly pathogenic in chicken and produced similar findings in oral and intraperitoneal infections; while per cloacal infection showed a localized infection of the caecum. Ref


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
AntibioticsDepending on sensitivity testing
Fermenting feedHelps chickens become less susceptible to Salmonella infection.L Heres et al., 2003
Baicalin (Scutellaria baicalensis) extract100-200 mg/kg of dietCui, Xiao-Die, et al 2023; Wang, Xian, et al. 2022; Zhang, Ling, et al. 2021; F Yang et al., 2020; Z Wu et al.,2020; Y Zhou et al., 2019; B Yin et al., 2021; M Bao et al., 2022; Z Hu et al., 2022
Probiotics and prebioticsAdded to dietH Al-Khalaifa et al., 2019; A Wolfenden et al., 2007
Thyme (Thymus vulgari) extract5 mg dried extract/mL (0.5% TVAE),V Elmi et al., 2020
Tumeric (Curcuma longa)0.1% in the feedD Hernandez-Patlan et al., 2019; K Varmuzova et al., 2015
Ashwagandha (Withania somnifera)0.5% of dietK Divua et al., 2015



  • Ferment feed
  • Do not buy chicks from mail-order hatcheries or feed stores.
  • Prevent high rodent populations.
  • Reduce biting fly populations

Scientific References

Good Overviews

Risk Factors

  • Buying chicks from mail-order hatcheries or feed stores.
  • High populations of rodents.
  • Age - Young (especially chicks less than 1 week of age), old, and unhealthy chickens are more susceptible to infection.