Oseltamivir as Parvovirus Treatment

Canine parvovirus (CPV) is a single-stranded DNA virus that attacks the crypts of the small intestines and causes severe life-threatening dehydration, vomiting, and diarrhea. The survival rate is less than 10% without treatment. With treatment, the survival rate is 67% to 100%, depending on the level of provided care. Oselta-mivir is a neuraminidase inhibitor that was originally designed to treat human influenza virus. Although CPV does not replicate using neura-minidase, some sources suggest that the antiviral drug can benefit CPV–infected patients by having an inhibitory effect on bacterial permeation through the mucin layer of the gut epithelial cells (a known path of patient morbidity in the disease). This inhibition would decrease bacterial translocation, resulting in a potentially lower incidence of endotoxemia, sepsis, systemic inflammatory response, and eventual multisystem failure. The authors note that in 1 study, 90% of dogs that died of parvoviral enteritis actually had Escherichia coli cultured from their livers and lungs.

In this randomized, prospective, placebo-controlled study, 35 client-owned dogs were randomly assigned to an oseltamivir treatment group or a placebo group. The dogs were enrolled if they tested positive for CPV by using a fecal antigen test; exhibited vomiting, diarrhea, lethargy, and anorexia; and had not received treatment before enrollment. All dogs were treated the same in terms of fluid replacement, antibiotics, antiemetics, and deworming, and a clinical scoring system was used to assess each dog’s progress. The authors reported that the treatment and control groups did not significantly differ in the degree of dehydration at presentation, days in the hospital with systemic inflammatory response syndrome, white blood cell counts, duration of hospitalization, and clinical scores for attitude/appetite/vomiting/feces. Three dogs died in the control group, and no dogs died in the treatment group (although this difference was not statistically significant). Body weight had increased significantly in the treatment group, however, possibly suggesting that oseltamivir may have a gastroprotective effect. By decreasing bacterial adherence and subsequent bacterial translocation through neuroamidase inhibition, oseltamivir would result in less cytokine release from the gut-associated lymphatic tissue and perhaps cause less severe disease.

Commentary: The use of antiviral drugs to treat canine disease has been particularly noted in recent outbreaks of canine influenza—the public outcry for oseltamivir caused controversy in the veterinary community because no published data supported its use in dogs. This study presents novel evidence that perhaps the drug could be useful in other diseases as well as traditional respiratory diseases, even though only 1 clinically pertinent measure was observed in the treatment dogs (weight gain).

Use of oseltamivir in the treatment of canine parvoviral enteritis. Savigny MR, Macintire DK. J VET EMERG CRIT CARE 20:132-142, 2010.