Page 921 - Clinical Small Animal Internal Medicine

82 Canine Viral Enteritis 859

derived immunity wanes and remain susceptible until hypokalemia, control pain and maintain nutrition.
VetBooks.ir they acquire active immunity, either through natural Antimicrobials should be administered to prevent and
treat secondary bacterial infections (gram‐negative and
infection or through vaccination. The outcome of infec-
tion, ranging from subclinical infection to severe disease,
the compromised gastrointestinal tract or from neutrope-
seems to depend on individual host factors, with some anaerobic) that arise from bacterial translocation across
breeds (notably American pit bull terriers, Rottweilers, nia. Frequent (q8h) monitoring of blood glucose is neces-
Doberman pinschers, and German shepherds) having sary and supplementation of intravenous (IV) fluids with
increased risk for severe enteritis. dextrose is often needed. Colloid therapy with hetastarch
or plasma may be necessary in some patients, particularly
those with severe hypoalbuminemia (Figure 82.1).
History and Clinical Signs Red cell transfusion may be necessary in patients with
significant blood loss. While treatment with recombi-
Most puppies infected with CPV‐2 present with a his- nant human granulocyte stimulating factor and hyper-
tory of lethargy and inappetence. These signs are often immune serum has not been shown to be of benefit,
accompanied by fever, abdominal pain, vomiting and feline interferon‐omega has shown promising results.
diarrhea, which may lead to substantial dehydration.
Although profuse, hemorrhagic diarrhea is a typical
finding, many dogs with CPV enteritis will produce scant Prognosis
mucoid feces instead. Extensive damage to the small
intestinal mucosa may result in coliform bacterial sep- Puppies with severe enteritis have a very poor survival
ticemia and endotoxic shock. rate without treatment due to hypovolemic and septic
Lymphopenia is a consistent clinicopathologic finding; shock and electrolyte/acid–base disturbances, while
other changes may include neutropenia, anemia, thrombo- hospitalization with fluid therapy greatly improves their
cytopenia, electrolyte imbalances (especially hypokalemia), prognosis for recovery. A protocol for outpatient treat-
hypoglycemia, and hypoalbuminemia. Serum C‐reactive ment of puppies whose owners cannot afford hospital
protein levels are often elevated in critically ill dogs and care has been developed and is showing promise for
correlate loosely with increased risk of mortality. improving the prognosis in these patients.
Myocarditis occurs with perinatal infection of puppies
born to naive bitches; puppies may present with dysp-
nea, weakness, and crying or experience sudden death. Prevention
This syndrome is not commonly seen in vaccinated and/
or CPV‐endemic populations.
Prevention of CPV‐2 infection is accomplished by limit-
ing contact of susceptible animals with potentially
Diagnosis infected animals and premises while stimulating immu-
nity with vaccination. Shelters, kennels, clinics, and
Although parvovirus infection is the likely diagnosis in other high‐density units need to practice good sanita-
an unvaccinated puppy presenting with enteritis, fever, tion, disinfection, and appropriate use of quarantine pro-
and lymphopenia, other enteric viruses may have a simi- tocols and isolation facilities.
lar presentation. Diagnosis of parvoviral enteritis is best Because maternally derived antibody can interfere with
accomplished by observation of clinical signs along with immunization, vaccination with modified live virus vac-
detection of CPV‐2 antigen (point‐of‐care enzyme‐ cine is recommended every 3–4 weeks beginning at 6
linked immunosorbent assay [ELISA] or hemagglutina- weeks of age until the puppy is 16 weeks old (or 20 weeks
tion) or DNA (polymerase chain reaction [PCR]) in feces old for high‐risk breeds). Although current vaccines,
or rectal swab specimens. PCR‐based tests are more sen- which are composed of CPV‐2 or CPV‐2b, have been
sitive than antigen tests and can be used to identify the effective in protecting dogs against CPV‐2c infection
variant of the infecting CPV. under experimental conditions, it is still unclear how pro-
tective these vaccines are under some field conditions.

Therapy
Public Health Implications
Ideally, puppies infected with CPV‐2 should be hospital-
ized and kept in isolation. Therapy for CPV‐2 enteritis Canine parvovirus‐2 variants do not infect people, but
consists of aggressive supportive care to correct hydra- feces should be treated as if other infectious agents that
tion, hypoglycemia, and electrolyte abnormalities such as cause intestinal disease in people are present.