Introduction

Actinobacillus suis, or A. suis is a beta-haemolytic

Hemolysis (microbiology)

Hemolysis is the breakdown of red blood cells. The ability of bacterial colonies to induce hemolysis when grown on blood agar is used to classify certain microorganisms. This is particularly useful in classifying streptococcal species...

, Gram-negative bacterium of the Pasteurellaceae

Pasteurellaceae

Pasteurellaceae comprise a large and diverse family of Gram-negative Proteobacteria with members ranging from important pathogens such as Haemophilus influenzae to commensals of the animal and human mucosa. Most members live as commensals on mucosal surfaces of birds and mammals, especially in the...

 family.

The bacterium has many strains and is the pathogen responsible for Actinobacillosis

Actinobacillosis

Actinobacillosis is a zoonotic disease caused by Actinobacillus.It is more commonly associated with animals than with humans.One of the most commons form seen by veterinarians is the mouth actinobacillosis of cattle, due to Actinobacillus lignieresii...

 in pigs of all ages. It can also infect wild birds, domestic ruminants, dogs, cats and horses.

The organism can be found in the respiratory tract and tonsil

Tonsil

Palatine tonsils, occasionally called the faucial tonsils, are the tonsils that can be seen on the left and right sides at the back of the throat....

s of both infected and healthy pigs that act as carriers. Transmission

Transmission (medicine)

In medicine and biology, transmission is the passing of a communicable disease from an infected host individual or group to a conspecific individual or group, regardless of whether the other individual was previously infected...

 is via the respiratory tract and piglets are usually infected early on in life.

Herds with a high health status are more at risk and outbreak

Outbreak

Outbreak is a term used in epidemiology to describe an occurrence of disease greater than would otherwise be expected at a particular time and place. It may affect a small and localized group or impact upon thousands of people across an entire continent. Two linked cases of a rare infectious...

s can be explosive.

Clinical Signs and Diagnosis

Affected piglets can develop septicaemia

Sepsis

Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...

, multifocal infections, respiratory signs, and may die.

Adult pigs may show signs relating to pneumonia

Pneumonia

Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...

, lethargy, anorexia

Anorexia (symptom)

Anorexia is the decreased sensation of appetite...

, skin lesions similar to Erysipelas

Erysipelothrix rhusiopathiae

Erysipelothrix rhusiopathiae is a gram-positive, catalase-negative, rod-shaped bacterium. It grows aerobically and anaerobically and does not contain endotoxin. Distributed worldwide, E. rhusiopathiae is primarily considered an animal pathogen, causing a disease known as erysipelas in animals...

 and sudden death.

Diagnosis relies on the culture

Microbiological culture

A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture media under controlled laboratory conditions. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested,...

 of sampled tissues to isolate the organism.

Signs and necropsy findings may mimic diseases such as: Erysipelas

Erysipelothrix rhusiopathiae

Erysipelothrix rhusiopathiae is a gram-positive, catalase-negative, rod-shaped bacterium. It grows aerobically and anaerobically and does not contain endotoxin. Distributed worldwide, E. rhusiopathiae is primarily considered an animal pathogen, causing a disease known as erysipelas in animals...

, Glasser's Disease, Streptococcus suis

Streptococcus suis

Streptococcus suis is a peanut-shaped, Gram-positive bacterium, and an important pathogen of pigs. Endemic in nearly all countries with an extensive pig industry, S. suis is also a zoonotic disease, capable of transmission to humans from pigs. Humans can be infected with S...

and Actinobacillus pleuropneumoniae.

Treatment and Control

Antibiotics such as ceftiofur

Ceftiofur

Ceftiofur is an antibiotic of the cephalosporin type , licensed for use in veterinary medicine. It was first described in 1987. It is marketed by pharmaceutical company Pfizer as Excede....

, gentamicin

Gentamicin

Gentamicin is an aminoglycoside antibiotic, used to treat many types of bacterial infections, particularly those caused by Gram-negative organisms. However, gentamicin is not used for Neisseria gonorrhoeae, Neisseria meningitidis or Legionella pneumophila...

 and trimethoprim

Trimethoprim

Trimethoprim is a bacteriostatic antibiotic mainly used in the prophylaxis and treatment of urinary tract infections.It belongs to the class of chemotherapeutic agents known as dihydrofolate reductase inhibitors...

/sulfadiazine are effective in treating the disease if diagnosis is rapid enough.

Biosecurity

Biosecurity

Biosecurity is a set of preventive measures designed to reduce the risk of transmission of infectious diseases, quarantined pests, invasive alien species, living modified organisms...

 measures should be strictly followed in herds, including adequate quarantine

Quarantine

Quarantine is compulsory isolation, typically to contain the spread of something considered dangerous, often but not always disease. The word comes from the Italian quarantena, meaning forty-day period....

time, testing and disinfection protocols.