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What is the primary characteristic of salmonellosis?
What is the primary characteristic of salmonellosis?
Salmonella bongori is responsible for the majority of salmonella infections in humans.
Salmonella bongori is responsible for the majority of salmonella infections in humans.
False
Name one serovar of Salmonella that specifically infects cattle.
Name one serovar of Salmonella that specifically infects cattle.
Salmonella typhimurium
Salmonella enterica contains two species: Salmonella enterica and __________.
Salmonella enterica contains two species: Salmonella enterica and __________.
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Which of the following serovars is associated with severe systemic disease in pigs?
Which of the following serovars is associated with severe systemic disease in pigs?
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Match the following serovars with their host specificity:
Match the following serovars with their host specificity:
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Most serotypes of Salmonella are specific to a single host species.
Most serotypes of Salmonella are specific to a single host species.
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What family does the genus Salmonella belong to?
What family does the genus Salmonella belong to?
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What is a primary method of introducing Salmonellosis infection into a herd?
What is a primary method of introducing Salmonellosis infection into a herd?
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Salmonella can multiply in environments with no oxygen present.
Salmonella can multiply in environments with no oxygen present.
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Name one economic loss associated with Salmonellosis.
Name one economic loss associated with Salmonellosis.
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The _____ is a toxic virulence factor of Salmonella.
The _____ is a toxic virulence factor of Salmonella.
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Which Salmonella serovar is known for its multidrug-resistant characteristics?
Which Salmonella serovar is known for its multidrug-resistant characteristics?
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Match the following Salmonella characteristics:
Match the following Salmonella characteristics:
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Host-restricted Salmonella serovars are associated with less severe disease in young animals.
Host-restricted Salmonella serovars are associated with less severe disease in young animals.
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What is one step in the pathogenesis of septicemic Salmonellosis?
What is one step in the pathogenesis of septicemic Salmonellosis?
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What is a common clinical finding in young animals affected by septicemia due to salmonellosis?
What is a common clinical finding in young animals affected by septicemia due to salmonellosis?
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A definitive diagnosis of salmonellosis can be made by serological tests alone.
A definitive diagnosis of salmonellosis can be made by serological tests alone.
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What pathogen is commonly associated with outbreaks of abomasitis in veal calves?
What pathogen is commonly associated with outbreaks of abomasitis in veal calves?
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The primary treatment for salmonellosis is __________ therapy.
The primary treatment for salmonellosis is __________ therapy.
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Match the following clinical findings with their descriptions:
Match the following clinical findings with their descriptions:
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What is the likely outcome for animals that survive the septicemic state of salmonellosis?
What is the likely outcome for animals that survive the septicemic state of salmonellosis?
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Feces from animals with acute enteritis due to salmonellosis may contain blood and have a putrid smell.
Feces from animals with acute enteritis due to salmonellosis may contain blood and have a putrid smell.
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What is a highly specific and sensitive test for the detection of salmonellas in fecal samples?
What is a highly specific and sensitive test for the detection of salmonellas in fecal samples?
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Which of the following serovars are considered typhoidal and cause enteric fever?
Which of the following serovars are considered typhoidal and cause enteric fever?
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Non-typhoidal Salmonella can cause systemic infections primarily in healthy adults.
Non-typhoidal Salmonella can cause systemic infections primarily in healthy adults.
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What is the most common symptom of acute gastroenteritis caused by non-typhoidal Salmonella?
What is the most common symptom of acute gastroenteritis caused by non-typhoidal Salmonella?
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Salmonella infections can lead to ______ in immunosuppressed hosts and very young individuals.
Salmonella infections can lead to ______ in immunosuppressed hosts and very young individuals.
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Match the following symptoms to their corresponding description of non-typhoidal Salmonella infections:
Match the following symptoms to their corresponding description of non-typhoidal Salmonella infections:
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What is the initial rate of intravenous sodium bicarbonate administration for electrolyte therapy?
What is the initial rate of intravenous sodium bicarbonate administration for electrolyte therapy?
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Live attenuated vaccines for salmonellosis are less effective immunogens in calves than killed vaccines.
Live attenuated vaccines for salmonellosis are less effective immunogens in calves than killed vaccines.
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What measures should be taken to prevent the spread of salmonellosis within a herd?
What measures should be taken to prevent the spread of salmonellosis within a herd?
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Salmonella-contaminated meats and poultry are associated with approximately ________ confirmed cases of salmonellosis annually in the USA.
Salmonella-contaminated meats and poultry are associated with approximately ________ confirmed cases of salmonellosis annually in the USA.
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Match the following Salmonella classifications with their characteristics:
Match the following Salmonella classifications with their characteristics:
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What should be done with the water supply in farms to prevent salmonellosis?
What should be done with the water supply in farms to prevent salmonellosis?
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Rigorous disinfection of buildings is not critical for salmonellosis control.
Rigorous disinfection of buildings is not critical for salmonellosis control.
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What is the estimated economic cost of salmonellosis in humans per year in Canada?
What is the estimated economic cost of salmonellosis in humans per year in Canada?
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Study Notes
Salmonellosis Definition
- Caused by Salmonella bacteria invading the intestines.
- Primarily characterized by septicemia and enteritis.
- Can extend to other areas, leading to abomasitis, polyarthritis, endarteritis & gangrene of limbs.
Salmonellosis Etiology
- Salmonella is a genus of motile, gram-negative, rod-shaped, flagellated, facultative anaerobic bacteria.
- Belongs to the Enterobacteriaceae family.
- Contains two species: Salmonella enterica and Salmonella bongori, with numerous serotypes within each.
- Majority of serotypes (59%) belong to S. enterica subsp. enterica, the remaining 41% to S. bongori.
- Serotypes are classified based on flagellar and lipopolysaccharide (LPS) antigens.
- S. enterica serovars are responsible for most Salmonella infections in humans and domesticated animals.
- Serovars exhibit host specificity.
Salmonellosis Etiology: Serovar Host Specificity
- Important serotypes in farm animals:
- Cattle: S. typhimurium, S. dublin, Salmonella newport
- Sheep and goats: S. abortusovis, S. typhimurium, S. dublin, Salmonella anatum
- Pigs: S. typhimurium, S. choleraesuis
- Horses: S. typhimurium, S. abortusequi, S. anatum, S. newport, S. enteritidis, Salmonella heidelberg, Salmonella arizona, Salmonella angona.
Salmonellosis Etiology: Serovar Infection Range
-
Serovars infect a wide range of hosts:
- Example: S. typhimurium and S. enteritidis are ubiquitous in the environment and usually associated with mild enteric disease.
-
Serovars with very restricted host range:
- Example: S. typhi is specific to humans, S. abortusovis to sheep, S. abortusequi to horses, S. choleraesuis to pigs, causing severe systemic disease within their respective hosts.
-
Serovars associated with disease in one primary species but infecting other hosts:
- Example: S. Transport can cause intercurrent disease.
Salmonellosis Epidemiology
- Intensified husbandry practices across species increase risk of salmonellosis.
- Changes in herd management also increase risk.
- Intensive pasture utilization and contaminated feedstuff are common transmission routes.
- Large-scale calf rearing units can suffer epidemics with significant morbidity and mortality.
- Carrier animals, infected clothing of visitors, and casual workers can introduce the infection.
Salmonellosis Epidemiology: Pathogen Risk Factors
- Salmonellas are relatively resistant to environmental factors.
- Can multiply within a pH range of 4 to 8, in oxygen-deficient environments, and some are multidrug resistant (e.g., S. typhimurium DT104).
- However, they are sensitive to pasteurization and beta- and gamma-irradiation.
- The O-antigen of lipopolysaccharide in Salmonella is toxic and an important virulence factor.
- Fimbriae play a role in virulence by facilitating adherence to host immunological cells.
Salmonellosis Economic Importance
- Economic losses include:
- Costs of clinical disease: Reduced weight gains, poor growth, reduced milk production.
- Deaths.
- Diagnosis and treatment costs.
- Cleaning and disinfection costs.
- Control and prevention costs.
Salmonellosis Pathogenesis
- Host-specific Salmonella serovars demonstrate increased pathogenicity to their respective hosts.
- Broad host-range serovars cause less severe disease, except in young animals (e.g., typhimurium and enteritidis).
- Host-restricted serovars cause significant mortality in both young and adult animals.
- Septicemic and enteric forms of salmonellosis are not mutually exclusive.
Salmonellosis Pathogenesis: Septicemic Form
- Occurs through oral infection.
- Invasion of the distal ileum and cecum mucosa.
- Replication in the submucosa of the ileum and cecum, and in Peyer's patches.
- Spread to the reticuloendothelial cells of the liver and bloodstream (bacteremia).
- A febrile reaction occurs 24-48 hours post-bacteremia.
- Septicemia leads to exudative panenteritis.
- Early septicemia can be rapidly fatal.
- Survivors develop a carrier state.
Salmonellosis Pathogenesis: Other Organs
- Abomasitis: S. typhimurium DT104 is associated with abomasitis in veal calves.
- Abortion: Can occur in the second and third trimesters of pregnancy.
- Terminal dry gangrene, osteitis, and polyarthritis: Osteitis is inflammation of bone.
Salmonellosis Clinical Findings: Septicemia
- Common in young animals.
- Significant depression, dullness, collapse, high fever (40.5-42°C) & death within 24-48 hours.
- Survivors of septic stage develop severe enteritis with diarrhea.
- Further survival can lead to residual polyarthritis or pneumonia.
Salmonellosis Clinical Findings: Acute Enteritis
- Common in adult animals of all species.
- High fever (40-41°C).
- Severe, fluid diarrhea, sometimes dysentery.
- Occasional tenesmus.
- Fever often subsides after diarrhea onset.
- Feces have a putrid smell and contain mucus, blood, and fibrinous casts.
Salmonellosis Clinical Pathology
- Definitive diagnosis relies on bacterial culture from feces, blood, milk, and other body fluids or tissues.
- Serological tests are available but lack sensitivity and specificity.
- PCR assays are highly specific and sensitive for Salmonella detection in fecal samples from horses.
- Real-time PCR assays have a high sensitivity (100%) and specificity (98.2%) compared to bacterial culture.
Salmonellosis Necropsy Findings: Septicemia
- Extensive submucosal and subserosal petechial hemorrhages are often evident.
Salmonellosis Necropsy Findings: Acute Enteritis
- Mucoenteritis with submucosal petechiae to diffuse hemorrhagic enteritis.
- Severe necrotic enteritis in the ileum and large intestine.
Salmonellosis Treatment
- Primary treatment is antimicrobial therapy:
- Early broad-spectrum antimicrobials are effective in reducing mortality and restoring function.
- Fluid and electrolyte therapy:
- Intravenous 5% sodium bicarbonate solution (5-8 L per 400 kg BW over 2 hours) for initial electrolyte replacement.
- Glucose or fructose administration for weak animals.
Salmonellosis Control
- Prevent introduction of the infection (biosecurity).
- Limit spread within a herd: Identify carriers and either cull them or isolate and treat them vigorously.
- Restrict movement of animals around the farm.
- Provide water in troughs protected from fecal contamination.
- Rigorous disinfection of buildings is essential.
- Adopt an all-in/all-out policy with steam cleaning and chemical sterilization after each batch of animals.
- Control measures are necessary in veterinary clinics and teaching hospitals to prevent spread of infection.
- Farm hygiene and biosecurity are crucial for control.
Salmonellosis Control: Vaccination
- Killed bacterins and live attenuated vaccines are available.
- Both can be used prenatally to passively immunize newborns.
- Live Salmonella vaccines are more effective immunogens in calves than killed vaccines.
Salmonellosis Zoonotic Importance
- Salmonella-contaminated meats and poultry: CDC reports about 40,000 confirmed cases of salmonellosis annually in the USA.
- Estimated cost to Americans is over US$1 billion annually, and US$100 million per year in Canada.
- Costs include hospital and medical costs, lost production, leisure, investigations, and loss of life.
Salmonellosis Zoonotic Importance: Salmonellae in Humans
- Salmonellae are divided into typhoidal and non-typhoidal serotypes.
Salmonellosis Zoonotic Importance: Typhoidal Serovars
- Human-restricted, invasive, typhoidal serotypes include:
- S. enterica var typhi [S typhi]
- S. enterica var paratyphi A [S Paratyphi A]
- Cause systemic disease, enteric (typhoid) fever.
- Characterized by fever and abdominal pain.
- Serovars Typhi and Paratyphi cause:
- Typhoid fever
- Paratyphoid fever
Salmonellosis Zoonotic Importance: Non-Typhoidal Salmonella (NTS)
- Enteritidis and typhimurium are major NTS.
- Wide host range.
- Cause acute, self-limiting gastroenteritis in humans, cattle, swine, and poultry.
- Can also cause bacteremia and systemic infections in:
- Immunosuppressed individuals
- Very young
- Older individuals
- Occasionally in healthy adults
Salmonellosis Zoonotic Importance: NTS Clinical Manifestations
- Acute gastroenteritis:
- Bloody stools
- Systemic symptoms: Fever, chills, myalgias, and headache
- Vomiting is less common.
- Diagnosis confirmed by stool culture or fecal polymerase chain reaction testing.
- Septicemia: Bacteremia is the most common systemic infection.
- Salmonella Carriage: Chronic carriage is more frequent in children.
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Description
This quiz covers the definition and etiology of Salmonellosis, focusing on the role of Salmonella bacteria in causing intestinal infections. Learn about the different species and serotypes of Salmonella and their host specificity, particularly in farm animals. Test your knowledge on these crucial aspects of this infectious disease.
