Veterinary Time: Episode 1 "Four viruses that can kill your dog"

Four viruses that can kill your dog: what they are, what they do and how you can prevent them from harming your pet.

Ask any vet, the answer will be the same, there are many diseases that can cause serious harm to your beloved canine pals, but viral diseases, in particular, have proved to be among the deadliest. These micro-organisms can be found in living hosts or on inanimate objects; some can mutate readily and become even more dangerous. The four viruses described in this article are amongst the deadliest culprits of canine suffering. Some are well known, while others are emerging threats.

What are viruses?

Viruses are micro-organisms, smaller than bacteria and, in many cases, considerably more dangerous. They have variable methods of reproduction (replication), all of which require that the virus is inside a living cell and rely on using the infected cell’s own mechanisms, including nuclear and peri-nuclear structures. Viruses are highly mutable, so emerging strains of known viruses may not be covered by currently available vaccines.

Herpes virus

Ubiquitous, this little fellow may cause non lethal disease in your adult, immunocompetent (with a fully functioning immune system) dog, but it may spell certain disaster for a gestating puppy. In utero contamination leads to non-progressive cerebellar hypoplasia i.e., a smaller cerebellum (a part of the central nervous system that relates itself to muscular coordination), abortion, or stillborn puppies. At the time of writing there is no treatment for this cerebellar condition. Vaccination of your pets is the only effective preventive measure, and will certainly help save unborn puppies.

Distemper virus

Few cases of Distemper are reported in the USA, however this virus is quite common in developing countries and where the pet-owning population hasn’t adopted proper vaccination strategies for their pets. The virus causes an acute, severe and multifaceted clinical picture (2), characterized by coughing, nasal and ocular secretion, severe gastrointestinal signs and, eventually, persistent neurological signs, including seizures and myoclonus (generalized rhythmical muscle contractions). The unvaccinated dog will most commonly succumb to hypovolemic shock on account of vomiting and diarrhoea. The treatment for Distemper disease is merely supportive and often fails. Patients that survive the acute phase of the disease can lead acceptable lives, despite the persistent, chronic neurological signs.

Parvovirus

As the name says, it’s a comparatively small virus, but one that causes a very acute and more often than not, lethal gastrointestinal disease. Parvoviral disease in dogs is characterized by severe gastrointestinal bleeding. Once the disease debuts in the unvaccinated puppy, death can follow quite quickly due to dehydration. The first step in treatment is rapid fluid administration and, in some cases, blood transfusion. This micro-organism can survive for very long periods in the environment, and can be found quite anywhere, even in veterinary clinics lacking the appropriate sanitation protocols.

Rabies Virus

Controlled in many parts of the world, this virus continues to be a concern, especially in rural areas and developing countries. Certainly the most famous of the four viral diseases described in this article, rabies is a deadly zoonosis –a disease that can be transmitted from animal to man (and vice versa) and is therefore subject of public health policy (3) (rabies vaccination is obligatory in many countries). Dogs afflicted with rabies develop an untreatable neurological condition, of which the hallmark is severe behavioural change, dominated by highly aggressive tendencies (1). The patient can cause harm to itself and others. There is no viable treatment for rabies in pets so the animal has to be sacrificed. There are many vaccines available on the market.

Conclusion.

The vaccination status of a pet is of primary importance in combating viral disease. Despite the mutable nature of viruses and the lack of a 100% coverage against emerging strains offered by current products, vaccination remains the preferable option, considering that the immunized will stand a bigger chance of survival compared with the non-immunized. Consult with your veterinarian about safe alternatives to vaccinate your pet today!

References

(1) Sarah N Lackay, MS Yi Kuang, MD, Zhen F. Fu, DVM, PhD. Rabies In Small Mammals.Vet Clin Small Anim 38 (2008) 851-861.

(2) Vito Martella, DVM, Gabrielle Elia, DVM, Canio Buonavoglia, DVM. Canine Distemper Virus. Vet Clin Small Anim 38 (2008) 787-797.

(3) Juan A Hirose, Adriana Villegas. Estructura antigenica y mecanismos de infeccion del virus de la rabia. Ciencia Veterinaria 7 (1996). 66-101.