By Carol A. Kemper, MD, FACP

Dr. Kemper reports no financial relationships relevant to this field of study.

“A New Wave of World-wide Gastroenteritis?”

SOURCE: de Graaf M, van Beek J, Vennema H, et al. Emergence of a novel GII.17 norovirus End of the GII.4 era? Euro Surveill 2015;20:21178.

The unexpected appearance in Japan of a previously relatively uncommon norovirus genotype, responsible for a series of gastroenteritis outbreaks at the end of 2014/winter 2015, has led to speculation that a new cycle of norovirus outbreaks is beginning.

Norovirus is likened to a “shape shifter” because of its frequent evolutionary antigenic changes, taking advantage of gaps in human immunity to re-emerge in new cycles of infection every few decades. Of the 30 or so genotypes in circulation, only seven have been seen with any frequency, and one (GII.4) has been predominant since the 1990s, responsible for 70% to 80% of gastroenteritis illness around the globe. The antigenic changes of GII.4 virus have, however, gone beyond the usual changes seen in “drifted” virus, instead engaging in infra-genotypic recombinations in their open reading frames (all of which is accomplished asexually). As such, GII.4 Sydney replaced the GII.4 New Orleans strain as the dominant world-wide strain in 2012-2013. Over the past few years, norovirus outbreaks have gradually diminished as the global population developed immunity to the GII.4 viruses. Amazingly, all of this is tracked by the Noronet database, which monitors outbreaks of norovirus around the globe.

Enter GII.17. Like “C-beams glittering in the dark near the Tannhauser gate,” everything is lost in time. GII.17 has been circulating at low levels for nearly four decades, resulting in sporadic outbreaks in Africa and South America. But during the past two to three years, GII.17 Kawasaki 2014 virus has emerged as the predominant strain associated with outbreaks in China, Korea, and Japan, and appears poised to cause a world-wide explosion of diarrhea.

Current efforts at development of a norovirus vaccine have been aimed at the most common circulating genotypes. It remains to be seen whether vaccine–induced immunity will cross-react with GII.17. Current norovirus assays for detection of clinical infection will also need to be re-evaluated, to ensure they include this additional genotype.

Who Wants a Stoma if You Don’t Need One?

SOURCE: Thornell A, Angenete E, Bisgaard T, et al. Laparoscopic lavage for perforated diverticulitis with purulent peritonitis: A randomized trial. Ann Intern Med 2016;164:137-145.

Perforated diverticulitis resulting in purulent or fecal peritonitis historically has been treated with surgical control of the offending bowel with urgent open bowel resection and formation of an ileostomy or colostomy (called a Hartmann procedure, which involves sigmoid resection and end colostomy). Occasionally, a few lucky patients were candidates for resection of the affected portion of bowel with an end-to-end anastomosis without creation of a stoma. Patients with perforated diverticulitis suffered through the morbidity of the open surgical resection, which, in the elderly, was not inconsiderable, and eventually many patients were faced with the choice of re-operation for “take-down” or reversal of the stoma. In lieu of this approach, it has been debated for years whether laparoscopic lavage might offer a less invasive, less morbid approach for certain patients.

These authors prospectively assessed outcomes in 83 patients randomly assigned to surgical control (Hartmann’s procedure) vs. laparoscopic lavage or drainage. The primary endpoint was the percentage of patients requiring re-operation within 12 months. Interventional radiologic drainage and surgical stoma reversal were counted as re-operations. Secondary outcomes included duration of hospital stay, the number of re-admissions and procedures within a 12-month period, adverse events, and morbidity.

Patients with suspected purulent diverticulitis (not fecal peritonitis), as confirmed by evidence of free air and/or peritoneal fluid on radiographic studies, were randomly assigned by an evaluating surgeon as they presented for care. Only those individuals who were otherwise considered surgical candidates were enrolled in the study.

Of the 83 randomized patients, eight (9.6%) were found to have other reasons for their presentation, including four with colon cancer, three with small bowel perforations and/or ischemia, and one with gynecologic malignancy. One withdrew consent, and another patient ended up with an entirely different surgical procedure and was excluded. Of the remaining 73 patients, 38 underwent laparoscopic lavage and 35 surgical resection. Mean hospital stays were shorter for lavage patients compared with surgical patients (14 vs. 18 days, P = 0.047).

Interestingly, within 12 months, 25 (62.5%) patients in the surgical control group compared with 12 (28%) in the lavage group had one or more re-operations; 21 of those in the surgical group were for reversal of the stoma. Nearly one-third (29%) of the patients in the lavage group developed abscess, and two later required open surgical resection. In comparison, six (17%) in the surgical group developed abscess and one required re-operation. By 12 months, 14 (37%) patients in the lavage group developed abscess, and seven patients required re-admission for recurrent diverticulitis. In comparison, 21 patients in the surgical group required re-admission for stoma reversal. At the end of one year, seven patients in the lavage group had a stoma, compared to 28 patients in the surgical control group. Six patients in each group died.

As with most things, it’s all about how you look at the data. Two earlier clinical trails examining this same question came down on the side favoring surgical resection — morbidity from sepsis was better controlled, and the number of re-operations — not including stoma reversal — were fewer. These authors included both interventional radiologic procedures and stoma reversal as “surgical procedures” — which greatly skews the data toward laparoscopic lavage as resulting in fewer adverse events, fewer hospital days, and fewer “re-operations.”

Aside from these differences in how the data were assessed, the two approaches were fairly similar in their outcomes and mortality. Granted, no one desires a stoma, let alone a second surgical procedure for reversal. But the key here is disease control many of these patients are critically ill with sepsis, on multiple antibiotics; more than one-third of the lavage patients developed abscess and/or required re-hospitalization for recurrent diverticulitis within 12 months. How many more will do so within their lifetime? Further, nearly 10% of the patients had an alternative diagnosis for the presentation, including 5% with malignancy a diagnosis not made by lavage. If nothing else, surgical resection provides direct pathologic examination and removes the diseased organ. The accompanying editorial suggests that future research focus on identifying that subgroup of perforated diverticulitis patients most amenable to less invasive technologies.

A Side of Hep E with Your Pork Roast?

SOURCE: Guillois Y, Abravanel F, Miura T, et al. High proportion of asymptomatic infections in an outbreak of hepatitis E associated with a spit-roasted piglet, France, 2013. Clin Infect Dis 2016;62:351-357.

A cluster of three cases of acute hepatitis E (HEV) infection in October-November 2013 on a small coastal island off western France prompted an epidemiological investigation. The three individuals all lived in the same village, developed symptoms within a few weeks of one another, and all had attended the same wedding in September. HEV strains from the three individuals exhibited homology and belonged to the same subtype 3f (genotype HEV3).

A total of 111 persons attended the wedding party, which involved a buffet of five mixed salads; a piglet stuffed with dressing that included raw piglet liver and roasted on a spit; barbecued lamb; grilled potatoes; flageolets and carrots; eight different goat cheeses; and six desserts. A questionnaire was administered to 98 wedding participants, 52 of whom provided a blood sample for PCR and serological testing; 50 (96%) of these lived on the island. Anyone with symptoms of jaundice or who reported hospitalization provided a blood sample. Remarkably, 14 wedding guests (27%) were found to have evidence of past HEV infection and were excluded from the remaining analyses, and 17 acute HEV cases (32.7%) were identified. More than two-thirds of these infections (70%) were asymptomatic.

A retrospective cohort study found a significant correlation between acute HEV infection and ingestion of piglet stuffing. A visit to the piglet farm found that the drinking water used for the animals came from a surface pond below the stock manure pit. All nine samples of water and piglet manure were positive for HEV. In addition, HEV was detected in untreated sewage samples from two of the island’s wastewater treatment facilities in December; samples from one of those facilities were still positive in late January 2014. All of the isolates were genotype 3f, and two of the HEV virus obtained from samples of liquid manure at the farm were 100% identical to the clinical specimens. Further analysis demonstrated that all of the isolates formed a distinct phylogenetic cluster.

The likely culprit for this outbreak was ingestion of inadequately cooked pork or pork liver, although the wedding foodstuffs were no longer available for direct testing and, given the frequency of previous HEV infection in the participants, any of the cooks could have theoretically been responsible. Based on serological data, HEV infection appears to be fairly common on this small French island likely because of infection in their swine population. Nearly one-third of adults had been previously infected. An important observation from this study was the high frequency (70%) of subclinical infections, and the persistence of low-grade HEV infection in island wastewater samples several months later indicates sustained infection in the islanders. The authors noted that HEV is inactivated by cooking at 71°C (159.8°F) not even above the temperature of boiling water for at least 20 minutes. It’s best to avoid eating undercooked meat when you travel.