Canine Parainfluenza

Introduction: Canine parainfluenza is a respiratory infectious disease of dogs characterized by cough, runny nose and fever caused by canine parainfluenza virus (CPIV). It mainly infects puppies, with acute onset and rapid spread. Canine parainfluenza virus infection is very similar to CAV-2, herpes virus, respiratory distemper virus, and reovirus infection, so it is difficult to confirm the diagnosis based on clinical symptoms.

Canine parainfluenza is a respiratory infectious disease in dogs characterized by cough, runny nose and fever caused by canine parainfluenza virus (CPIV). CPIV is one of the pathogens of puppy cough, mainly infecting puppies, with acute onset and rapid spread.

This illness has occurred in various parts of the world.

Pathogenic characteristics of canine parainfluenza

CPIV is a member of the type 2 parainfluenza virus subgroup in the Paramyxoviridae family, also known as simian virus type 5 (SV5).

Virus particles are basically round, but vary in size and are polymorphic. The diameter is between 80 and 300 nm, and some are filamentous. Virus particles have capsules, fibrous protrusions on the surface, and have hemagglutination. The genome is single-stranded negative-sense RNA.

The virus is unstable, and if stored at 4°C and room temperature, the infectivity will decrease rapidly. pH3.0 and 37℃ can rapidly inactivate the virus. Sensitive to chloroform and ether, quaternary ammonium salts are effective disinfectants.

The virus can agglutinate type O red blood cells of humans, sheep, guinea pigs, pigs, chickens, foxes and dogs. The optimal conditions for hemagglutination are 22°C pH7.4, 0.5% sheep or human red blood cells.

The virus can proliferate on cells such as chicken embryos, dogs, monkeys, and kidneys, resulting in multinucleated syncytial lesions and eosinophilic inclusion bodies in the nucleus. Toxigenic cells have an adsorption effect on guinea pig erythrocytes.

Epidemiological characteristics of canine parainfluenza

CPIV infection is found in all dog-raising countries and regions, and there are also suspected outbreaks in my country.

Dogs of all ages, breeds, and sexes are susceptible, but puppies are more susceptible.

Respiratory secretions infect other dogs through air dust as the main way of shedding the virus, and can also be transmitted through contact. During the infection period, Bordetella and Mycoplasma infections may be secondary to dogs with reduced resistance.

Symptoms of Canine Parainfluenza

In natural infection cases, the onset is often sudden, with cough of different frequency and degree, loss of appetite and fever of different degrees, followed by serous, mucous or even purulent nasal discharge.

Symptoms of Canine Parainfluenza

Watery discharge from eyes and nose
Resource description: There is watery serous nasal fluid at the end of the nose.

Simple CPIV infection can usually recover naturally within 3-7 days, and cough can last for several weeks after secondary infection, and even death.

In addition to secretions in the respiratory tract, tonsils, trachea, and bronchi have inflammatory lesions, and sometimes bleeding points can be seen in the lungs. Histological examination showed a large number of monocytes and neutrophils infiltrated in the submucosal area above.

In recent years, it has also been reported that canine parainfluenza virus type 2 can also infect brain tissue and intestinal tract, causing encephalomyelitis, hydrocephalus and enteritis. The dog presented with clinical signs characterized by hindlimb paralysis and signs of enteritis.

Diagnosis of canine parainfluenza

Because canine parainfluenza virus infection is very similar to CAV-2, herpes virus, respiratory distemper virus, and reovirus infection, it is difficult to confirm the diagnosis based on clinical symptoms.

Virus isolation and identification are more reliable. Usually in the early stage of the disease, respiratory secretions are collected, and the sterilized supernatant is used to inoculate canine kidney or chicken embryo fibroblasts. If multinucleated fusion cells appear, the cells have the characteristics of absorbing guinea pig red blood cells, or the culture can agglutinate sheep or human red blood cells, and can be inhibited by specific antibodies, can be confirmed.

Fluorescence-labeled specific antibodies can also be used to react with tracheal and bronchial epithelial cells. If specific fluorescent cells appear, the diagnosis can be made.

Take double sera at the early stage of the disease and the recovery period, and use specific antigens to measure neutralizing antibodies or hemagglutination-inhibiting antibodies. If the serum titer increases by more than 2 times, it can be judged as parainfluenza virus infection. This method can be used as a method of retrospective diagnosis and epidemiological investigation.

Prevention and treatment of canine parainfluenza

The main points of clinical treatment of canine parainfluenza generally include:

  1. The use of phlegm-resolving and cough-relieving agents can alleviate the condition;
  2. Injection of antibiotics can prevent secondary infection of Bordetella;
  3. Injection of hyperimmune serum has an emergency preventive effect.

Most of the preventive vaccines for canine parainfluenza virus infection are attenuated live vaccines, which are combined with attenuated vaccines such as canine distemper, viral enteritis, and infectious hepatitis. The five-link attenuated vaccine developed by Xia Xianzhu and others has been approved for production by the state, and the immune effect is reliable.