Infectious bovine keratoconjunctivitis
Encyclopedia
Infectious bovine keratoconjunctivitis, or IBK, is a veterinary infection of cattle caused by Moraxella bovis
, a gram negative, β-haemolytic, aerobic, rod shaped bacterium
. It is spread by direct contact or by the common fly
serving as a vector. It is the most common ocular disease of cattle
(mostly beef). IBK is similar to human pink eye and causes severe infection of the conjunctiva
, edema
, corneal opacity and ulceration. This disease is highly contagious and occurs worldwide. Younger animals are more susceptible but recovery with minimal damage is usual, if they are treated early. The disease is better known as pinkeye, New Forest Eye or blight.
is a gram-negative
rod-shaped aerobe. These bacteria are obligate intracellular parasite
s of the mucous membrane
s and can usually be isolated from the respiratory tract
, vagina
and conjunctiva of healthy animals. Transmission of IBK is through direct contact with mucous membranes and their secretions and indirect contact where flies act as a mechanical vector. Asymptomatic carrier
animals can also be source of infection.
radiation is implicated in cattle with no pigmentation around the eyelids and cattle with prominently placed eyes. Exudate
s from the sun-burnt skin around the eyes become a culture media for bacteria and attract flies. UV also directly damages the cornea
l epithelium
leading to a break-down in host innate immunity
.
Dust, dried up plants and long vegetation causes mechanical damage to the eye and facilitate bacterial colonization.
Concurrent infection with viruses such as infectious bovine rhinotracheitis virus (bovine herpesvirus 1
) or adenovirus, bacteria such as Mycoplasma boviculi or Listeria monocytogenes, or Thelazia
, a nematode
, complicates the disease.
Vitamin A deficiency
is also implicated.
Pinkeye is most prevalent in summer and early autumn.
A recent Meat & Livestock Australia (MLA) report "estimates that the disease costs Australian beef producers $23.5 million annually in lost production and treatment costs".
, uveitis
and ulceration. Cattle show signs of pain, increased lacrimation and conjunctivitis
.
More severe cases may show systemic signs such as inappetance and weight loss. Chronic untreated cases can become blind.
Diagnosis is usually based on the clinical signs, but the bacteria can be cultured
from lacrimal swabs, or visualised on smears of lacrimal secretions.
impregnated ear tags, and lower stocking rate may help prevent IBK. Early identification of the disease also helps prevent spread throughout the herd. Treatment is with early systemic use of a long acting antibiotic
such as tetracycline or florfenicol
. Subconjunctival injections with procaine penicillin
are also effective.
Anti-inflammatory
therapy can help shorten recovery times, but topical corticosteroids
should be used with care if corneal ulcers are present.
M. bovis uses several different serotype
d fimbriae as virulence factor
s, consequently pharmaceutical companies have exploited this to create vaccines. However, currently available vaccine
s are not reliable.
Moraxella bovis
Moraxella bovis is a Gram-negative, aerobic, oxidase-positive diplococcus that is implicated in infectious keratoconjunctivitis in cattle, also colloquially known as Pink Eye.-Weblinks:* - Department of Primary Industries...
, a gram negative, β-haemolytic, aerobic, rod shaped bacterium
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
. It is spread by direct contact or by the common fly
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
serving as a vector. It is the most common ocular disease of cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
(mostly beef). IBK is similar to human pink eye and causes severe infection of the conjunctiva
Conjunctiva
The conjunctiva covers the sclera and lines the inside of the eyelids. It is composed of rare stratified columnar epithelium.-Function:...
, edema
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
, corneal opacity and ulceration. This disease is highly contagious and occurs worldwide. Younger animals are more susceptible but recovery with minimal damage is usual, if they are treated early. The disease is better known as pinkeye, New Forest Eye or blight.
Cause
Moraxella bovisMoraxella
Moraxella is a genus of Gram-negative bacteria in the Moraxellaceae family. It is named after the Swiss ophthalmologist Victor Morax. The organisms are short rods, coccobacilli or, as in the case of Moraxella catarrhalis, diplococci in morphology, with asaccharolytic, oxidase-positive and...
is a gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
rod-shaped aerobe. These bacteria are obligate intracellular parasite
Obligate intracellular parasite
Intracellular parasites are parasitic microorganisms - microparasites that are capable of growing and reproducing inside the cells of a host.-Facultative:...
s of the mucous membrane
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
s and can usually be isolated from the respiratory tract
Respiratory tract
In humans the respiratory tract is the part of the anatomy involved with the process of respiration.The respiratory tract is divided into 3 segments:*Upper respiratory tract: nose and nasal passages, paranasal sinuses, and throat or pharynx...
, vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
and conjunctiva of healthy animals. Transmission of IBK is through direct contact with mucous membranes and their secretions and indirect contact where flies act as a mechanical vector. Asymptomatic carrier
Asymptomatic carrier
An asymptomatic carrier is a person or other organism that has contracted an infectious disease, but who displays no symptoms. Although unaffected by the disease themselves, carriers can transmit it to others...
animals can also be source of infection.
Predisposing factors
UltravioletUltraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
radiation is implicated in cattle with no pigmentation around the eyelids and cattle with prominently placed eyes. Exudate
Exudate
An exudate is any fluid that filters from the circulatory system into lesions or areas of inflammation. It can apply to plants as well as animals. Its composition varies but generally includes water and the dissolved solutes of the main circulatory fluid such as sap or blood...
s from the sun-burnt skin around the eyes become a culture media for bacteria and attract flies. UV also directly damages the cornea
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...
l epithelium
Epithelium
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...
leading to a break-down in host innate immunity
Innate immune system
The innate immune system, also known as non-specific immune system and secondary line of defence, comprises the cells and mechanisms that defend the host from infection by other organisms in a non-specific manner...
.
Dust, dried up plants and long vegetation causes mechanical damage to the eye and facilitate bacterial colonization.
Concurrent infection with viruses such as infectious bovine rhinotracheitis virus (bovine herpesvirus 1
Bovine herpesvirus 1
-Introduction:Bovine herpesvirus 1 is a virus of the family Herpesviridae and the subfamily Alphaherpesviridae, known to cause several diseases worldwide in cattle, including rhinotracheitis, vaginitis, balanoposthitis, abortion, conjunctivitis, and enteritis...
) or adenovirus, bacteria such as Mycoplasma boviculi or Listeria monocytogenes, or Thelazia
Thelazia
Thelazia is a genus of nematode worms which parasitize the eyes and associated tissues of various bird and mammal hosts, including humans. They are often called "eyeworms," and infestation with Thelazia species is referred to as "thelaziasis"...
, a nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
, complicates the disease.
Vitamin A deficiency
Vitamin A deficiency
Vitamin A deficiency is a lack of vitamin A in humans. It is common in developing countries but rarely seen in developed countries. Night blindness is one of the first signs of vitamin A deficiency. Xerophthalmia and complete blindness can also occur since Vitamin A has a major role in...
is also implicated.
Pinkeye is most prevalent in summer and early autumn.
A recent Meat & Livestock Australia (MLA) report "estimates that the disease costs Australian beef producers $23.5 million annually in lost production and treatment costs".
Clinical Signs and Diagnosis
The bacteria invade the lacrimal glands of the eye, causing keratitisKeratitis
Keratitis is a condition in which the eye's cornea, the front part of the eye, becomes inflamed. The condition is often marked by moderate to intense pain and usually involves impaired eyesight.-Types:...
, uveitis
Uveitis
Uveitis specifically refers to inflammation of the middle layer of the eye, termed the "uvea" but in common usage may refer to any inflammatory process involving the interior of the eye....
and ulceration. Cattle show signs of pain, increased lacrimation and conjunctivitis
Conjunctivitis
Conjunctivitis refers to inflammation of the conjunctiva...
.
More severe cases may show systemic signs such as inappetance and weight loss. Chronic untreated cases can become blind.
Diagnosis is usually based on the clinical signs, but the bacteria can be cultured
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,...
from lacrimal swabs, or visualised on smears of lacrimal secretions.
Treatment and control
Shade, insect repellentInsect repellent
An insect repellent is a substance applied to skin, clothing, or other surfaces which discourages insects from landing or climbing on that surface. There are also insect repellent products available based on sound production, particularly ultrasound...
impregnated ear tags, and lower stocking rate may help prevent IBK. Early identification of the disease also helps prevent spread throughout the herd. Treatment is with early systemic use of a long acting antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
such as tetracycline or florfenicol
Florfenicol
Florfenicol is a fluorinated synthetic analog of thiamphenicol.In the United States, florfenicol is currently indicated for the treatment of bovine respiratory disease associated with Mannheimia haemolytica, Pasteurella multocida, and Haemophilus somnus, for treatment of bovine...
. Subconjunctival injections with procaine penicillin
Procaine benzylpenicillin
Procaine benzylpenicillin , also known as procaine penicillin, is a form of penicillin which is a combination of benzylpenicillin and the local anaesthetic agent procaine...
are also effective.
Anti-inflammatory
Anti-inflammatory
Anti-inflammatory refers to the property of a substance or treatment that reduces inflammation. Anti-inflammatory drugs make up about half of analgesics, remedying pain by reducing inflammation as opposed to opioids, which affect the central nervous system....
therapy can help shorten recovery times, but topical corticosteroids
Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...
should be used with care if corneal ulcers are present.
M. bovis uses several different serotype
Serotype
Serotype or serovar refers to distinct variations within a subspecies of bacteria or viruses. These microorganisms, viruses, or cells are classified together based on their cell surface antigens...
d fimbriae as virulence factor
Virulence factor
Virulence factors are molecules expressed and secreted by pathogens that enable them to achieve the following:* colonization of a niche in the host...
s, consequently pharmaceutical companies have exploited this to create vaccines. However, currently available vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
s are not reliable.
Vaccination
Coopers Animal Healthhttp://www.coopersanimalhealth.com.au/, a division of Schering-Plough, has released a new vaccine "Piliguard"http://www.pinkeye.com.au/ in Australia. The vaccine contains three strains of Morexella bovis (SAH38, FLA 64, EPP 63) pilli antigen. This stimulate antibody production against the bacterial pilli to prevent their attachment and invasion of the conjuntiva. The company claims that the vaccine reduce the incidence and severity of the disease in an individual animal which directly reduce animal suffering and production loss on top of limiting the spread of disease through the herd. This in turn reduces the amount of antibioitcs and fly repellent needed during high-risk seasons. The vaccine is marketed in multidose-vials and have an adjuvant to create a long-term subcutaneous depot. This means that no booster shot is necessary but severe local reaction can be seen in people who accidentally self-inoculate. Calves as young as 1 week old can be treated and there is no meat, milk or export slaughter interval withhold.External links
- Infectious Bovine Keratoconjunctivitis expert reviewed and published by Wikivet at http://en.wikivet.net/Infectious_Bovine_Keratoconjunctivitis accessed 06/10/2011.