For Most, Rotavirus Is Now Just Another Cause of Gastroenteritis

In the post-vaccine era, rotavirus has become just another cause of acute gastroenteritis in most cases. But is there anything new in diagnosis and treatment?

To Test or Not to Test?

Commercially available tests for rotavirus include enzyme-linked immunoassay (EIA) commercial kits that detect rotavirus antigen in stool samples and multi-pathogen polymerase chain reaction (PCR)-based assays that test for a wide variety of viral and bacterial gastrointestinal pathogens.

However, physicians don't often use any diagnostics for suspected cases of rotavirus, Paul Offit, MD, of the Children's Hospital of Philadelphia, told MedPage Today. For emergency department physicians or pediatricians, "do they make an attempt to do a so-called gastroenteritis panel? I would imagine that most don't," primarily because a positive rotavirus test would not alter treatment of the disease, Offit said. "It's not going to matter."

Robert Frenck Jr., MD, a pediatrician and director of the Vaccine Research Center at Cincinnati Children's Hospital, noted that "testing really would be to see if you have a bacterial cause or to prove that you have a viral cause, because if you have a viral cause, you don't use antibiotics ... so the main reason for diagnosis is to guide treatment."

Frenck told MedPage Today that viruses cause the vast majority of gastroenteritis in children. Clues that help to distinguish a bacterial infection from viral gastroenteritis include blood-streaked stool, higher fever, and an elevated white blood cell count.

If clinicians do have patients in whom testing is warranted -- such as those with symptoms severe enough to be hospitalized -- most facilities have replaced individual rotavirus EIA tests with multiplex PCR gastroenteritis panels, Frenck explained. "We've been using [similar panels] for respiratory pathogens for a while and now it's really migrated into diarrheal disease and enteric pathogens."

Brian Chow, MD, an infectious diseases specialist at Tufts Medical Center in Boston, told MedPage Today that at his facility, multi-pathogen diagnostic panels have generally replaced specific rotavirus antigen tests. "For simplicity, it's actually easier, and depending on the assay, it could be more cost-effective just to test for all of these [enteric pathogens] at the same time," in part because the panel requires fewer staff resources to run and read than individual assays, he said.

For individuals with some types of diseases, diagnosis of specific enteric pathogens can be critical, noted Lasha Gogokhia, MD, a gastroenterology fellow at Weill Cornell Medical Center in New York City, who treats patients with inflammatory bowel disease (IBD) who must often take immunosuppressive medications.

"They come to the hospital with worsening of acute symptoms and we don't know if this is related to the worsening of their IBD or if it is from an infection," Gogokhia told MedPage Today. All immunocompromised patients admitted with diarrhea at his hospital are tested using multiplex PCR tests, he added.

According to CDC data, the number of laboratories reporting EIA test results for rotavirus to the National Respiratory and Enteric Virus Surveillance System in the post-vaccine era has declined by about 50%. On the other hand, use of PCR tests for rotavirus has increased substantially in just a few years' time, from 19 laboratories reporting 16,490 PCR test results for the 2014-2015 season to 80 laboratories reporting 87,775 PCR test results during the 2017-2018 season.

Treatment: It's Mostly Supportive

Because rotavirus generally resolves in a few days to 1 week in most patients, the key to treating severe cases of rotavirus is managing dehydration, said Genon Wicina, MD, a pediatrician at Cleveland Clinic Martin Health in Stuart, Florida. "The biggest thing is hydration ... Sometimes it's not just diarrhea, it's both ends, so it's very difficult to keep up with them sometimes."

For her pediatric outpatients, she recommends that parents offer small, frequent sips of fluids, crushed up Popsicles, Italian ice, jello, or soups -- anything with a lot of water. "We try to manage it just with oral rehydration to help them avoid having to go to the emergency room for IV fluids," she told MedPage Today.

Offit concurred with this approach for most outpatients with suspected rotavirus. "Time will ultimately be their cure. It's not like COVID, for example, when you make the diagnosis of COVID and the patient is in a high-risk group, you could treat it," he said. "There really is no specific treatment for rotavirus."

Guidelines recommend oral rehydration over IV rehydration in children with mild-to-moderate gastroenteritis.

In the pre-vaccine era in the U.S., vomiting was a major stumbling block to outpatient treatment. "That's what made this so frustrating for parents, was that they would call the doctor, the doctor would say, 'Give frequent sips of fluids containing sugar and electrolytes and salt,'" Offit said. "The parents wouldn't be able to do that because of the fact that this is a vomiting illness."

Red flags that point to the need for IV rehydration in children with gastroenteritis include bloody diarrhea, overall worsening of vomiting and diarrhea, reduced peripheral perfusion, decreased skin turgor, altered responsiveness, tachypnea, tachycardia, and a fever above 104º F.

Although treatment of rotavirus infection in immunocompromised patients also includes supportive therapy, Gogokhia said that he sometimes prescribes nitazoxanide, a broad-spectrum antiviral drug that has been shown to reduce duration of rotavirus-associated illness in some studies. "The shortest course of infection we can maintain, the better," in patients with IBD, he emphasized.

Gogokhia also pointed out that use of antidiarrheal drugs that decrease intestinal motility, such as loperamide, are generally discouraged for diarrhea from infectious causes, but can be used with caution in viral gastroenteritis if there is profuse, watery diarrhea that may lead to rapid dehydration. However, loperamide should not be given to children younger than age 2.

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