Rotaviruses cause acute intestinal infections in humans, dogs and other species throughout the world. The Latin word, "rota," means wheel, and rotavirus structures appear wheel-like. These highly contagious viruses live in the environment, and infection can occur more than once because several types of rotaviruses exist. The effects of these viruses are maximized in the youngest animals.
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Infection
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Adult dogs can become infected with a rotavirus, but will not suffer its ill effects. The most debilitating symptoms appear in puppies less than 12 weeks of age. Symptoms exhibited include diarrhea, appetite loss and low energy. The virus is transmitted in a fecal-oral route. Viral particles shed by infected dogs in feces enter the new viral host by mouth.
Effects
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Once the virus enters the digestive tract, it travels to its target organ, the intestine. The stomach acid has no negative effect on the viral protective capsule. In the intestine it attaches to the intestinal lining and infects the cells. The swelling and degeneration of infected intestinal cells decreases their absorptive capability, resulting in watery diarrhea. Thus, shed viral particles contaminate the environment in the excreted feces.
Transmission
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Since transmission is fecal-oral, proper hygiene is necessary for prevention. In humans proper hygiene includes hand-washing and disinfection, but for dogs it becomes complicated. Preventing canine transmission includes keeping young dogs away from public areas and other dogs. Also, removing feces from yards and parks prevents environmental contamination. Transmission to nursing puppies is from the mother, an unavoidable transmission process. Luckily, the illness is short-lived, and puppies have a high survival rate.
Shedding
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Viral shedding refers to reproduction, expulsion and new infections caused by virus progeny. The route and duration of viral shedding varies according to the type of viral species. Large numbers of rotaviruses shed during episodes of diarrhea. The shedding is detectable using an electron microscope on fecal exams, but this very expensive instrument is not readily available to most veterinarians. Diagnostics may not be necessary, due to the short duration of infection.
Treatment
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Treatment of rotavirus infection is entirely supportive. Administering fluids and electrolytes prevents diarrheal dehydration. Puppies need careful monitoring, and all sick animals should be kept warm and dry. No completely effective way of eliminating rotavirus infection or spreading is available, and no vaccine is available for dogs at this time.
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