Canine herpesvirus
Encyclopedia
Canine herpesvirus is a virus of the family Herpesviridae
which most importantly causes a fatal hemorrhagic
disease in puppies
(and in wild Canidae
) less than two to three weeks old. It is known to exist in the United States
, Canada
, Australia
, Japan
, England
and Germany
. CHV was first recognized in the mid 1960s from a fatal disease in puppies.
of CHV is six to ten days. CHV is transmitted to puppies in the birth canal and by contact with infected oral and nasal secretions from the mother or other infected dogs, but it is not spread through the air. The virus replicates in the surface cells of the nasal mucosa
, tonsil
s, and pharynx
. Low body temperature allows the virus to spread and infect the rest of the body. Symptoms include crying, weakness, depression, discharge from the nose, soft, yellow feces
, and a loss of the sucking reflex
. CHV also causes a necrotizing vasculitis
that results in hemorrhage
around the blood vessels. Bruising of the belly may occur. Eye lesions include keratitis
, uveitis
, optic neuritis
, retinitis, and retinal dysplasia
. There is a high mortality rate, approaching 80 percent in puppies less than one week old, and death usually occurs in one to two days.
In puppies three to five weeks old, the disease is less severe due to their ability to properly maintain body temperature and mount a febrile
response. More puppies survive, but they can develop a latent infection. Some later get neurologic disease
and have symptoms like difficulty walking and blindness. Reactivation of a latent infection may be caused by stress or immunosuppressive drugs such as corticosteroid
s. The site of latency has been shown to be the trigeminal ganglion
and possibly the lumbosacral ganglion.
s, the virus infects the reproductive tract, which allows it to be sexually transmitted or passed to puppies during birth. The disease can cause abortion
, stillbirth
s, and infertility
. It is also an infrequent cause of kennel cough
.
Like other types of herpesvirus, previously infected dogs can from time to time release the virus in vagina
l secretions, penile
secretions, and discharge from the nose. Raised sores in the vagina or on the penis
may be seen during these times. Spread of the disease is controlled by not breeding dogs known to have it. Serology
can show what dogs have been exposed (although not all of them will be releasing the virus at that time). Serological studies of various dog populations have revealed a seroprevalence of 40 to 93 percent. Bitches who have a negative serology for CHV should be isolated from other dogs from three weeks before to three weeks after giving birth. Bitches that have lost puppies to the disease may have future litters that survive due to transfer of antibodies
in the milk.
s, liver
, lung
s, and gastrointestinal tract
. Treatment of affected puppies is difficult, although injecting antibodies to CHV into the abdomen may help some to survive. Keeping the puppies warm is also important. The virus does not survive well outside of the body and is easily destroyed by most detergent
s. A vaccine in Europe known as Eurican Herpes 205 (ATCvet code: ) has been available since 2003. It is given to the dam (mother) twice: during heat or early pregnancy and one to two weeks before whelping.
for gene therapy
in dogs and as a basis for recombinant
vaccines are ongoing. Its use as a vector in bait-delivered oral vaccines in wild fox
es is also being investigated.
Herpesviridae
The Herpesviridae are a large family of DNA viruses that cause diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word herpein , referring to the latent, recurring infections typical of this group of viruses...
which most importantly causes a fatal hemorrhagic
Bleeding
Bleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
disease in puppies
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
(and in wild Canidae
Canidae
Canidae is the biological family of carnivorous and omnivorous mammals that includes wolves, foxes, jackals, coyotes, and domestic dogs. A member of this family is called a canid . The Canidae family is divided into two tribes: Canini and Vulpini...
) less than two to three weeks old. It is known to exist in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
and Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
. CHV was first recognized in the mid 1960s from a fatal disease in puppies.
CHV in puppies
The incubation periodIncubation period
Incubation period is the time elapsed between exposure to a pathogenic organism, a chemical or radiation, and when symptoms and signs are first apparent...
of CHV is six to ten days. CHV is transmitted to puppies in the birth canal and by contact with infected oral and nasal secretions from the mother or other infected dogs, but it is not spread through the air. The virus replicates in the surface cells of the nasal mucosa
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...
, 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, and pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
. Low body temperature allows the virus to spread and infect the rest of the body. Symptoms include crying, weakness, depression, discharge from the nose, soft, yellow feces
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
, and a loss of the sucking reflex
Primitive reflexes
Primitive reflexes are reflex actions originating in the central nervous system that are exhibited by normal infants but not neurologically intact adults, in response to particular stimuli. These reflexes disappear or are inhibited by the frontal lobes as a child moves through normal child...
. CHV also causes a necrotizing vasculitis
Vasculitis
Vasculitis refers to a heterogeneous group of disorders that are characterized by inflammatory destruction of blood vessels. Both arteries and veins are affected. Lymphangitis is sometimes considered a type of vasculitis...
that results in hemorrhage
Bleeding
Bleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
around the blood vessels. Bruising of the belly may occur. Eye lesions include keratitis
Keratitis
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....
, optic neuritis
Optic neuritis
Optic neuritis is the inflammation of the optic nerve that may cause a complete or partial loss of vision.-Causes:The optic nerve comprises axons that emerge from the retina of the eye and carry visual information to the primary visual nuclei, most of which is relayed to the occipital cortex of the...
, retinitis, and retinal dysplasia
Retinal dysplasia
Retinal dysplasia is an eye disease affecting the retina of animals and, less commonly, humans. It is usually a nonprogressive disease and can be caused by viral infections, drugs, vitamin A deficiency, or genetic defects...
. There is a high mortality rate, approaching 80 percent in puppies less than one week old, and death usually occurs in one to two days.
In puppies three to five weeks old, the disease is less severe due to their ability to properly maintain body temperature and mount a febrile
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
response. More puppies survive, but they can develop a latent infection. Some later get neurologic disease
Neurology
Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the central, peripheral, and autonomic nervous systems, including their coverings, blood vessels, and all effector tissue,...
and have symptoms like difficulty walking and blindness. Reactivation of a latent infection may be caused by stress or immunosuppressive drugs such as corticosteroid
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...
s. The site of latency has been shown to be the trigeminal ganglion
Trigeminal ganglion
The trigeminal ganglion is a sensory ganglion of the trigeminal nerve that occupies a cavity in the dura mater, covering the trigeminal impression near the apex of the petrous part of the temporal bone.-Relations:It is somewhat crescentic in shape, with its convexity...
and possibly the lumbosacral ganglion.
CHV in adult dogs
In adult dogDog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s, the virus infects the reproductive tract, which allows it to be sexually transmitted or passed to puppies during birth. The disease can cause abortion
Miscarriage
Miscarriage or spontaneous abortion is the spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving independently, generally defined in humans at prior to 20 weeks of gestation...
, stillbirth
Stillbirth
A stillbirth occurs when a fetus has died in the uterus. The Australian definition specifies that fetal death is termed a stillbirth after 20 weeks gestation or the fetus weighs more than . Once the fetus has died the mother still has contractions and remains undelivered. The term is often used in...
s, and infertility
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...
. It is also an infrequent cause of kennel cough
Kennel cough
Kennel cough is a highly contagious canine illness characterized by inflammation of the upper respiratory system. It can be caused by viral infections such as canine distemper, canine adenovirus, canine parainfluenza virus, or canine respiratory coronavirus, or bacterial infections such as...
.
Like other types of herpesvirus, previously infected dogs can from time to time release the virus in 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...
l secretions, penile
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...
secretions, and discharge from the nose. Raised sores in the vagina or on the penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...
may be seen during these times. Spread of the disease is controlled by not breeding dogs known to have it. Serology
Serology
Serology is the scientific study of blood serum and other bodily fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum...
can show what dogs have been exposed (although not all of them will be releasing the virus at that time). Serological studies of various dog populations have revealed a seroprevalence of 40 to 93 percent. Bitches who have a negative serology for CHV should be isolated from other dogs from three weeks before to three weeks after giving birth. Bitches that have lost puppies to the disease may have future litters that survive due to transfer of antibodies
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
in the milk.
Diagnosis, treatment, and control
Diagnosis of the disease in puppies is best accomplished by necropsy. Findings include hemorrhages in the kidneyKidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s, liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
, lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s, and gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
. Treatment of affected puppies is difficult, although injecting antibodies to CHV into the abdomen may help some to survive. Keeping the puppies warm is also important. The virus does not survive well outside of the body and is easily destroyed by most detergent
Detergent
A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap but are less affected by hard water...
s. A vaccine in Europe known as Eurican Herpes 205 (ATCvet code: ) has been available since 2003. It is given to the dam (mother) twice: during heat or early pregnancy and one to two weeks before whelping.
Research
Studies of using CHV as a viral vectorViral vector
Viral vectors are a tool commonly used by molecular biologists to deliver genetic material into cells. This process can be performed inside a living organism or in cell culture . Viruses have evolved specialized molecular mechanisms to efficiently transport their genomes inside the cells they infect...
for gene therapy
Gene therapy
Gene therapy is the insertion, alteration, or removal of genes within an individual's cells and biological tissues to treat disease. It is a technique for correcting defective genes that are responsible for disease development...
in dogs and as a basis for recombinant
Recombinant DNA
Recombinant DNA molecules are DNA sequences that result from the use of laboratory methods to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in biological organisms...
vaccines are ongoing. Its use as a vector in bait-delivered oral vaccines in wild fox
Fox
Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...
es is also being investigated.