A Severe Malady Warranting Distinctive Measures: Canine Distemper.

A Severe Malady Warranting Distinctive Measures: Canine Distemper.

Deshmukh Kaivalya Ruprao¹, Bhand Akshata Chandrakant² , Ashmita Debnath³

¹M.V.Sc Scholar, Division of Animal Biochemistry, Indian Veterinary Research Institute, Izatanagar, Bareilly – 243122. Email ID – kaivalya.deshmukh17@gmail.com

 ²PhD Scholar, Division of Medicine, Indian Veterinary Research Institute, Izatanagar, Bareilly – 243122. Email ID – drakshatavmc@gmail.com 

³PhD Scholar, Division of Animal Biochemistry, Indian Veterinary Research Institute, Izatanagar, Bareilly – 243122. Email ID – meashmi0117@gmail.com 

             

Abstract:

Canine distemper (CD) is a highly contagious viral illness caused by a single-stranded RNA virus within the Paramyxoviridae family. It affects various carnivores, including domestic dogs, with a death rate ranking just below rabies. The virus spreads through respiratory exudates and bodily fluids, posing a risk to a wide range of host species. There is no known cure for CD, and treatment primarily involves supportive measures and vaccinations. CD’s ability to infect diverse hosts, including non-human primates, emphasizes its interspecies transmission potential. The disease’s persistence in wildlife reservoirs hinders eradication efforts. Awareness and immunization are crucial for public health, especially among professionals dealing with non-domestic carnivores.

Keywords : Canine Distemper, Virus, Transmission, Clinical Signs, Risk Factor, Diagnosis Treatment

Introduction

The extremely infectious viral illness known as canine distemper (CD) affects carnivores all over the world and manifests itself in skin, respiratory, and central nervous system forms . With the second-highest death rate after rabies, it presents a serious threat to both domestic and wild animals . Fever, rash, and immunosuppression are among the signs of CD that are similar to those of human measles and frequently result in neurological problems . A wide variety of carnivores are affected, including adults and dogs who have not had a vaccination . After being identified as a concern to household dogs, CD has also been linked to non-human primates, posing a risk to a range of wildlife species . Immunization is the only means of prophylaxis; the illness can cause pneumonia, conjunctivitis, and tracheitis, for which there is no known cure . Because CD may change hosts, it poses a threat to endangered species of animals because it can alter behavior, survival, reproduction, and community structure . The origin, transmission, host range, pathophysiology, clinical symptoms, diagnosis, and prevention of CD in many species are all discussed in this article.

Etiology:

The Morbilli virus, belonging to the Paramyxoviridae family, is the source of the canine distemper virus, which is a single-stranded RNA virus . These viruses, which may cause serious illnesses in both humans and animals, include the highly pathogenic measles, rinderpest, CD, and peste-des-petits-ruminants viruses . With six structural proteins and two auxiliary non-structural proteins located inside the P gene, the CD virus is an enveloped, negative-sense, single-stranded RNA virus . The reason behind its high pathogenicity in canines and other animals is its affinity for different types of cells. The CD virus causes systemic infections in several organ systems due to its manifestations of neurotropism, epitheliotropism, and lymphotropism . According to molecular investigations, the onset of the illness in new host species is associated with changes in the binding location of the haemagglutinin protein that impact the viral entry receptors, SLAM and VRL4.

Transmission:

Since the CD virus is rather brittle outside of the host, it requires intimate contact for horizontal transmission . It can endure lower temperatures for a brief period of time. In domestic dogs, transmission can happen by fomites, transplacental pathways, or direct contact . Even in the preclinical stages, infected animals excrete and secrete the virus, which can spread for up to ninety days . Via touch or aerosolized secretions, the virus spreads and causes fever, coughing, nasal discharge, and gastrointestinal symptoms. These symptoms are frequently exacerbated by subsequent bacterial infections. Severe, transient immunosuppression is a well-known side effect of morbillivirus infection .

Host range:

The host range of canine distemper virus (CDV) is quite extensive, encompassing a variety of mammals across several taxonomic orders. Here’s a breakdown of the susceptible groups:

Primary Hosts:

1) Carnivora (Carnivores): This order forms the vast majority of CDV’s host range, including:

2) Canidae (Dogs, foxes, wolves, coyotes, jackals)

3) Mustelidae (Weasels, ferrets, minks, skunks, badgers, otters, martens)

4) Procyonidae (Raccoons, coatis)

5) Ursidae (Bears)

6) Felidae (Big cats, excluding domestic cats)

7) Ailuridae (Red pandas)

 Secondary Hosts:

1) Primates: Some primate species, like the Japanese macaque, can become infected but rarely show clinical signs.

2) Rodentia: Certain rodents, like squirrels and guinea pigs, can be infected experimentally but usually don’t develop disease.

3) Artiodactyla (Even-toed ungulates): Some ungulates, such as deer and pigs, might harbor the virus without showing symptoms.

4) Proboscidea (Elephants): Only the Asian elephant has been documented with CDV infection.

Clinical Symptoms of Canine Distemper:

Early Stage:

1) Fever:

2) Lethargy:

3) Loss of appetite:

Watery or pus-like discharge from the eyes and nose:

4)Sneezing:

5)Coughing:

Later Stage:

1) Vomiting:

]2) Diarrhea: 

3) Thickening of the pads on the feet and nose:

4) Skin sores:

5) Difficulty breathing: MSD

6) Pneumonia:

 Neurological Signs:

1) Muscle twitching:

2) Chewing gum fits (convulsions with jaw-chewing movements):

3) Excessive drooling:

4) Head tilt: 

5) Circling:

6) Involuntary eye movements:

7) Paralysis or partial paralysis:

8) Seizures:

Risk Factors for Infection:

Dogs of any age can exhibit severe clinical symptoms from the canine distemper virus (CDV); age is not a protective factor. Puppies are especially vulnerable to the canine parvovirus because of their immature immune systems and the interference of their mothers’ antibodies, unlike older dogs that have some age-related protection. Vaccinating young pups under the age of 18 to 20 weeks might be particularly difficult. Regardless of their history of immunization, pups may be vulnerable due to maternal antibodies that might impede vaccination. Puppies frequently have more obvious clinical symptoms, which increases morbidity and death.

Diagnosis:

The veterinarian will gather your dog’s history, noting vaccination status, travel, and observed signs. A comprehensive physical exam will assess overall health and identify potential distemper indicators. Diagnostic tests include:

1. Blood tests (CBC, biochemistry) for infection or inflammation.
2. Viral Ag Detection (rapid tests, ELISAs) to detect CDV antigens in blood, conjunctival, or nasal samples. Results may vary early on.
3. Virus Isolation involves isolating the virus from tissues (e.g., blood, conjunctiva) in cell cultures for confirmation, but it’s time-consuming.
4. PCR, a highly sensitive test, detects viral genetic material in blood, tissues, or cerebrospinal fluid.
5. Histopathology (microscopic examination of tissues) may reveal CDV-related changes but is usually ancillary and not routine for diagnosis.

[Karki etal.,2022]

 Treatment:

The treatment of infectious Canine Distemper (CD) viral diseases in wildlife animals can be challenging. Unfortunately, there is no specific antiviral drug available for therapeutic use against CD viral infection in any species, including domestic dogs. Therefore, treatment typically focuses on symptomatic and supportive therapy.

Fluid Therapy: Veterinarians should provide balanced electrolyte solutions to maintain hydration in infected animals.

Nutrition: Parenteral nutrition may be necessary to support weakened animals.

Antibiotics: While there is no direct antiviral treatment, antibiotics can help prevent secondary bacterial infections.

Pain Management: Analgesics can alleviate discomfort.

Fever Control: Antipyretics help manage fever.

Neurological Support: Anticonvulsant drugs may be needed to control neurologic manifestations.

Nursing Care: Good nursing care is essential for infected animals.

It’s important to note that treatment options are limited, especially for free-ranging wild animals within protected areas. For captive animals, fluid therapy, antibiotics, and topical antiseptic applications are recommended.

Prevention and Control:

Global eradication of CD virus is challenging due to its broad wildlife distribution. Vaccination, especially with modified live virus vaccines for domestic dogs, is key . Nondomestic species should avoid standard attenuated virus vaccines, but a recombinant canary-poxvirus vectored vaccine is available .Antiviral research includes an oral morbillivirus inhibitor, fucoidan, flavonoids, and phenolic acids inhibiting CD virus replication in vitro . Therapeutic strategies involve immune modulation and oligodendrocyte reactivation .CD virus is fragile, susceptible to environmental factors, surviving only hours at room temperature but up to two weeks in shaded, near-refrigeration conditions . Quarantining infected animals is crucial due to prolonged shedding. Transmission occurs through respiratory exudates, demanding strict environmental hygiene. Control efforts should focus on susceptible animal groups in endemic areas . Challenges in wildlife vaccination include safety, efficacy, delivery mode, booster shots, and cost considerations .

Conclusion:

Canine distemper (CD) is a highly fatal viral disease affecting dogs and carnivores globally, with a fatality rate second only to rabies. It poses a significant threat to young and immune-compromised animals, impacting a wide range of carnivores. With no curative treatment and genetic variability, CD is a major clinical concern and an emerging threat to wildlife conservation. Vaccination is essential for prevention in endemic areas, as there is no curative treatment for CD infection.

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