''Canid alphaherpesvirus 1'' (CaHV-1), formerly ''Canine herpesvirus'' (CHV), is a virus of the family '' Herpesviridae'' which most importantly causes a fatal hemorrhagic disease in puppies (and in wild ''

Canidae Canidae (; from Latin, ''canis'', "dog") is a biological family of dog-like carnivorans, colloquially referred to as dogs, and constitutes a clade. A member of this family is also called a canid (). There are three subfamilies found within th ...

'') less than two to three weeks old. It is known to exist in the United States, Canada,

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, England and Germany. CHV was first recognized in the mid-1960s from a fatal disease in puppies.

CHV in puppies

The incubation period 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 A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...

, tonsils, 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 Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...

, and a loss of the

sucking reflex 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 are suppressed by the development of the f ...

. 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 Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using valu ...

response. More puppies survive, but they can develop a

latent infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...

. 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 Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involv ...

s. The site of latency has been shown to be the trigeminal ganglion and possibly the

lumbosacral ganglion The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordate ...

CHV in adult dogs

In adult dogs, 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 Stillbirth is typically defined as fetal death at or after 20 or 28 weeks of pregnancy, depending on the source. It results in a baby born without signs of life. A stillbirth can result in the feeling of guilt or grief in the mother. The term ...

s, and

infertility Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). It is the normal state ...

. It is also an infrequent cause of

kennel cough Kennel cough, also known as canine infectious respiratory disease, formally canine infectious tracheobronchitis, is an upper respiratory infection affecting dogs. There are multiple causative agents, the most common being the bacterium ''Bordete ...

. However, sexual contact is not the primary cause of transmission. Most adult dogs become infected by inhaling the virus via airborne particles spread by coughs or sneezes. It can also be contracted by drinking from a contaminated water bowl, or even just by sniffing or licking another dog that is shedding the virus. Like other types of herpesvirus, previously infected dogs can from time to time release the virus in vaginal secretions,

penile A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do ...

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 which 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 An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...

in the milk.

Diagnosis, treatment, and control

Diagnosis of the disease in puppies is best accomplished by necropsy. Findings include hemorrhages in the kidneys, liver,

lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...

s, and

gastrointestinal tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organ (biology), organs of the digestive syste ...

. 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 A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions. There are a large variety of detergents, a common family being the alkylbenzene sulfonates, which are soap-like compounds that are more ...

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 vector Viral vectors are tools commonly used by molecular biologists to deliver genetic material into cells. This process can be performed inside a living organism (''in vivo'') or in cell culture (''in vitro''). Viruses have evolved specialized molecul ...

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 Foxes are small to medium-sized, omnivorous mammals belonging to several genera of the family Canidae. They have a flattened skull, upright, triangular ears, a pointed, slightly upturned snout, and a long bushy tail (or ''brush''). Twelve sp ...

es is also being investigated.

References

External links

''Canine Herpes Infection'' from The Pet Health Library
{{Taxonbar, from=Q1033307, from2=Q24808690 Varicelloviruses Dog diseases Animal viral diseases