CRV Infections

Community respiratory virus (CRV), also known as community-acquired respiratory virus, is a serious concern in institutional settings, most notably hospitals and large medical centers 2. It is a particularly significant problem among patients whose immune systems have been compromised by certain medical conditions or artificially suppressed to facilitate transplant procedures. Although different viruses have been implicated in CRV infections, such infections are united in their tendency to spread rapidly in community settings.

Multiple Studies

CRV infections, the viruses that cause them and methods that can be used to limit their spread or severity all have been the subjects of scholarly studies over the last several decades. A disproportionate number of these studies—both domestic and international—have focused on the threat posed by CRV infections among immunosuppressed patient populations.

What Viruses Are Involved?

A number of viruses have been implicated as causes of CRV infections in hospital/medical center populations. A study conducted by researchers from the Section of Infectious Diseases at the University of Texas’s M.D. Anderson Cancer Center focused on viruses that caused CRV infections in adult bone marrow transplant patients hospitalized at the center during two six-month periods in the early 1990s 1.

They found that 36 percent of all transplant patients came down with a CRV infection during the first such period, while 26 percent were infected during the second period of surveillance. Almost half of the CRV infections were caused by respiratory synctial virus, with 18 percent each traced to influenza virus and picornaviruses, 9 percent to parainfluenza virus and 6 percent to adenovirus. The researchers reported that pneumonia—most viral in origin—complicated almost 60 percent of the recorded CRV infection cases.

New Virus Identified

A study published in the September 2002 issue of Emerging Infectious Diseases pointed to a new virus, human metapneumovirus (HMPV), as a culprit in CRV infections among some children hospitalized in the United Kingdom. Researchers described HMPV as a paramyxovirus and suggested that further study was necessary to determine the magnitude of its role in CRV infections.

Spanish Study

In a paper presented at the 43rd annual Interscience Conference on Antimicrobial Agents and Chemotherapy in 2003, Spanish researchers reported a high rate of CRV infections among solid organ transplant patients. Included in the study were 150 transplant patients (55 heart, 48 liver and 47 kidney). A total of 78 cases of CRV infection were observed, including two patients who had four separate episodes of infection and nine patients who had two separate episodes of infection. In all, 63 of the 150 patients studied contracted CRV infections, an infection rate of 42 percent.

Reducing Severity of Infection

A study published in a 2008 issue of Haematologica reported that the severity of CRV infections among stem cell transplant patients who underwent myeloablative conditioning was greater than among those undergoing non-myeloblative procedures. CRV infections in non-myeloblative patients were found less likely to progress to serious lower respiratory tract complications. Non-myeloblative conditioning permits transplantation without first eradicating the host’s hematopoietic (blood-producing) cells.