Salmonellosis is a bacterial
infection caused by salmonella bacteria which have two species Salmonella
Enterica and salmonella bungori and over 2400 serotypes. Some of those
serotypes are named in such cases people often shorten the scientific name to
include only the genus and serotype, for example, salmonella enterica subspecies
enterica serotype typhi is shortened to Salmonella Typhi. Salmonellosis is
usually transmitted through contaminated food or water and is typically caused
by serotypes of the salmonella enterica species, all Salmonella bacteria are
bacilli which means rod-shaped bacteria.
Salmonella has flagella all over its
surface allowing it to move the bacteria use a needle-like structure to inject
host cells with bacterial proteins during infection in humans most cases are
caused by the S enteritidis and S Typhimurium serotypes other serotypes of
salmonella and terrica cause similar infections in other
warm-blooded
animals these include
S gallinarum in poultry, S abortisovis in
sheep, S cholera suis in pigs, S Dublin in cattle and S Arizona
in reptiles among others. All of these strains can also infect humans salmonella
is typically transmitted through the fecal-oral root after infected feces come
into contact with various foods including raw meat poultry eggs unpasteurized
milk and crops salmonella can also be present on the skin of reptiles and birds
and be transmitted through contact with these animals.
When the bacteria are ingested they travel
through the digestive tract invading and multiplying in intestinal cells infected
cells then release pro-inflammatory cytokines causing an inflammatory response
this results in gastroenteritis or inflammation of the intestinal tract causing
abdominal pain and severe diarrhea the bacteria can also enter the blood termed
bacteremia and cause enteric fever from there they can make their way to other
organs like the liver lungs heart and bone to cause focal salmonella infection these
symptoms and signs usually arise in humans between 12 and 48 hours after ingestion
of the bacteria and typically last for four to seven days the salmonella
Typhimurium serotype can cause typhoid fever
which is characterized by
similar
symptoms including high fever, headache,
abdominal pain, and either constipation or diarrhea, unlike most other
salmonella infections typhoid fever can be life-threatening and often requires antibiotic
treatment in infected livestock.
Most adults have acute enteritis with
fever and severe diarrhea in horses’ abdominal pain may lead to colic in newborn
animals.
Enteritis is often followed by bacteremia. Diagnosis of salmonellosis
is based primarily on clinical signs and symptoms it can be confirmed by
culture of stool blood urine or tissue however test results usually come back after
symptoms have resolved and therefore diagnosis is usually based on the symptoms,
in animals diagnosis can often be suspected based on symptoms, but
salmonellosis will need to be distinguished from other causes of bacterial
enteritis as in people diagnosis can be confirmed by culture of feces, blood or
body tissues. Treatment for salmonellosis in people is focused mainly on
replenishing body fluids and electrolytes to remedy dehydration in some cases
hospitalization may be required to deliver fluids intravenously antibiotics are
typically avoided because they may prolong the infection in less severe cases however
if it is suspected that the salmonella infection is focal or systemic or if the
patient is immunocompromised antibiotics such as
Ciprofloxacin, Azithromycin,
Ceftriaxone or Trimethoprim-sulfamethoxazole may be prescribed early
treatment is essential for bacteremic salmonellosis in animals, but use of
antimicrobial agents for intestinal salmonellosis is controversial oral
antibiotics may be ineffective and there is concern about prolonging carriage
and excretion of the organism fluid therapy to correct acid-base imbalance and
dehydration may be necessary prevention is often the best course of action and
includes hand washing after touching raw meat or live animals, proper handling
of raw meat to avoid cross-contamination while preparing foods and adequate
cooking of meat and eggs before eating carrier animals which are asymptomatic adults
that shed the bacteria and contaminated feed are factors that make control
harder in livestock.
In many countries, government-backed programs
have been introduced to reduce infection levels among food animals especially
poultry and pigs vaccines are available for some animal species and may reduce
symptoms along with lowering herd infection rates.
Alright
as quick recap salmonellosis is an infection caused by salmonella bacteria it
is typically transmitted through contaminated food or water symptoms are caused
by an inflammatory response to the bacteria that often leads to diarrhea and
abdominal discomfort, Clinical diagnosis is usually adequate to guide rehydration
treatment but cultures should be done in severe cases to recognize serotypes
that require antibiotics
Thank you
