Strangles
Encyclopedia
Strangles is a contagious upper respiratory tract infection
of horses and other equines
caused by a bacterium, Streptococcus
equi var equi. Strangles is enzootic
in domesticated horse
s worldwide.
Equines of any age may contract the disease, although younger and elderly equines are more susceptible. Young equines may lack immunity because they have not had prior exposure. Elderly equines may have a weaker immune system.
discharge, and swollen or enlarged lymph node
s in the neck and throatlatch. Affected animals may also stop eating and have a dull affect.
Strangles has a 1% mortality rate
. Mortality is lower in cases without complications than it is in cases of bastard strangles. The disease is very contagious and morbidity is high. Precautions to limit the spread of the illness are necessary and those affected are normally isolated. An isolation period of 6 weeks is usually necessary to ensure that the disease is not still incubating before ending the isolation.
or penicillin-derivative antibiotics are the most effective treatments. However, some authorities are of the opinion that use of antibiotics are contra-indicated once abscesses have begun to form, as they pre-dispose to lymphatic spread of the infection (so-called bastard strangles) which has a much higher mortality rate.
After an abscess has burst, it is very important to keep the wound clean. A diluted povidone-iodine solution has been used with good results to disinfect the open hole, flushing the inside with a syringe tipped with a teat cannula
, followed by gentle scrubbing to keep the surrounding area clean.
, guttural pouch
es filled with pus, abscess
es, purpura hemorrhagica, and heart disease
. The average length for the course of this disease is 23 days.
Upper respiratory tract infection
Upper respiratory tract infections are the illnesses caused by an acute infection which involves the upper respiratory tract: nose, sinuses, pharynx or larynx...
of horses and other equines
Equidae
Equidae is the taxonomic family of horses and related animals, including the extant horses, donkeys, and zebras, and many other species known only from fossils. All extant species are in the genus Equus...
caused by a bacterium, Streptococcus
Streptococcus
Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs, hence the name — from Greek στρεπτος streptos, meaning...
equi var equi. Strangles is enzootic
Endemic (epidemiology)
In epidemiology, an infection is said to be endemic in a population when that infection is maintained in the population without the need for external inputs. For example, chickenpox is endemic in the UK, but malaria is not...
in domesticated horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
s worldwide.
Biology
The disease is spread when the nasal discharge or material from the draining abscess contaminates pastures, barns, feed troughs, etc.Equines of any age may contract the disease, although younger and elderly equines are more susceptible. Young equines may lack immunity because they have not had prior exposure. Elderly equines may have a weaker immune system.
Signs
Clinical signs include fever, heavy nasalNasal cavity
The nasal cavity is a large air filled space above and behind the nose in the middle of the face.- Function :The nasal cavity conditions the air to be received by the other areas of the respiratory tract...
discharge, and swollen or enlarged lymph node
Lymph node
A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
s in the neck and throatlatch. Affected animals may also stop eating and have a dull affect.
Strangles has a 1% mortality rate
Mortality rate
Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...
. Mortality is lower in cases without complications than it is in cases of bastard strangles. The disease is very contagious and morbidity is high. Precautions to limit the spread of the illness are necessary and those affected are normally isolated. An isolation period of 6 weeks is usually necessary to ensure that the disease is not still incubating before ending the isolation.
Treatment
As with many streptococcal infections, penicillinPenicillin
Penicillin is a group of antibiotics derived from Penicillium fungi. They include penicillin G, procaine penicillin, benzathine penicillin, and penicillin V....
or penicillin-derivative antibiotics are the most effective treatments. However, some authorities are of the opinion that use of antibiotics are contra-indicated once abscesses have begun to form, as they pre-dispose to lymphatic spread of the infection (so-called bastard strangles) which has a much higher mortality rate.
After an abscess has burst, it is very important to keep the wound clean. A diluted povidone-iodine solution has been used with good results to disinfect the open hole, flushing the inside with a syringe tipped with a teat cannula
Cannula
A cannula or canula is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of data...
, followed by gentle scrubbing to keep the surrounding area clean.
Complications
Possible complications include the horse becoming a chronic carrier of the disease, asphyxia due to enlarged lymph nodes compressing the larynx or windpipe, bastard strangles (spreading to other areas of the body), pneumoniaPneumonia
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...
, guttural pouch
Guttural pouch
In the equids and some rodent-like species such as the desert hyrax, the guttural pouch is a pair of air chambers in the neck just behind the skull and below the ears...
es filled with pus, abscess
Abscess
An abscess is a collection of pus that has accumulated in a cavity formed by the tissue in which the pus resides due to an infectious process or other foreign materials...
es, purpura hemorrhagica, and heart disease
Heart disease
Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...
. The average length for the course of this disease is 23 days.