Infection from Organ Donors:
Exploring the Risks of Accepting Life
By Kathy Dix
Organ and tissue donors are screened more thoroughly than any other group. Blood donors receive much the same treatment. But there are still pathogens that slip through the cracks. Of all the bugs that can be disseminated via organ or blood donation, West Nile Virus (WNV) has received the most recent press. In September, the Centers for Disease Control and Prevention (CDC) released case histories of four patients, all believed to be infected with WNV from a single donor.
The donor was the victim of a motor vehicle accident and received multiple blood transfusions before death. Physicians have not determined the source of her infection; it may be from the blood transfusions, or it may be from the more traditional mode of exposure: a mosquito bite.
Very little is known about WNV transmission through blood transfusions or organ donations. Such transmission has not been previously reported; therefore, no one can quantify the risk of contracting WNV via this route. So far, however, there is not enough evidence to support a change in existing screening and testing practices for organ or blood donors.
Because the aforementioned organ donor had been healthy before her injury, a mosquito bite or a blood transfusion is the most likely source of infection. Four patients received organs from the donor; three of these met the case definition for WNV encephalitis; testing is still pending on the fourth.
Recipient 1, who received a kidney, developed symptoms of WNV 13 days after transplant and is now recovering. Recipient 2, who also received a kidney, became ill 17 days after transplant and eventually died of encephalitis. Recipient 3, who received a heart, developed ataxia eight days after transplant and eventually required mechanical ventilation; his condition has improved and he no longer needs a ventilator. Recipient 4 developed fever, cough and malaise seven days after transplant but did not develop encephalitis; his symptoms resolved and he was discharged from the hospital.
What is striking about these patients is that three -75 percent - developed encephalitis. Generally, one in 150 people with WNV develop encephalitis or meningitis. CDC points out that "it is unknown whether immunosuppressed persons, such as organ transplant recipients, are at increased risk for severe WNV-related disease following infection. Similarly, it is unknown if the route of transmission increased the risk for encephalitis in these organ transplant recipients."1
A separate case -- this time involving a blood transfusion -- also worried health officials, who wondered if the patient acquired her infection via blood transfusion or a simple mosquito bite. She had received 18 pints of blood during an obstetric procedure, but she also presented with multiple mosquito bites on admission.2
Because the virus does not normally live long in the blood, it was previously believed that WNV could not be transmitted via blood or organ donations. But the events of 2002 have turned that theory on its head.
CDC stresses one item in particular: WNV infection is a possibility in patients who receive organ transplants and blood transfusions. But CDC officials note the investigation is ongoing and that in the meantime, clinicians with patients who are febrile following transplant bear in mind the possibility of WNV infection, especially if the patient has developed encephalitis or meningitis.
The panic of viral infection control in the 1980s is hardly forgotten. When HIV and AIDS first came to the attention of the general public, the disease was found in homosexual and heterosexual people alike -- including hemophiliacs and surgery patients who had received blood transfusions. Since then, screening programs have become standard to detect HIV-infected blood. Blood donors are asked about at-risk behaviors every time they donate. Even the blood of those at low risk is screened for HIV each and every time.
The families and friends of deceased organ donors are asked about at-risk behaviors of the donor to determine if there is a high risk of HIV infection. "Questions include sexual behavior (especially homosexual or promiscuous behavior), intravenous drug abuse, blood transfusion history, etc. The questioning of the next of kin obviously is not the perfect history, since many do not know the details of their (loved ones' lives), but it is the best information we can get ... and we do decline donations of patients who test negative for HIV but have questionable social history," writes Andrew Wheelock of the New England Organ Bank in response to a question about AIDS acquired from transplants.3
Wheelock refers to a highly publicized case of one donor infecting many recipients with the HIV virus, but emphasizes the sophisticated screening process used now.
Of course, there are other transplant issues associated with HIV. Many patients who are HIV positive but in need of transplants have difficulty even getting on a list of prospective recipients. Although United National Organ Sharing (UNOS) has guidelines allowing HIV-positive patients to be included in organ transplants, some regional centers still frown upon transplanting organs in HIV patients. Some people believe that the immunosuppression necessary with organ transplants will have a significant effect on the immune systems of HIV patients.4
Even if they are considered for a transplant -- and willing to receive organs from HIV-positive donors -- those organs are hard to come by, what with the custom of refusing HIV-positive donors and even people suspected of at-risk behavior.
And if all these roadblocks were cleared, there are still the insurance companies to contend with. What insurer will pay for transplantation of an HIV-positive organ in an HIV-positive recipient?
In 2001, one woman with HIV and hepatitis C Virus (HCV) campaigned for her insurer to pay for a liver transplant; when the insurer refused, Belynda Dunn took her appeal to the Massachusetts Office for Patient Protection. Although the office upheld the insurer's decision, the mayor of Boston spearheaded a fundraising campaign to pay for the surgery. The insurer eventually agreed to pay all costs above what had been raised. The transplant was performed in March 2002, but the first liver was rejected and Dunn died of a blood clot in the lung after the second transplant.5
Such stories highlight the ongoing controversy about HIV patients; are they viable candidates for transplants? Should HIV-positive organs be used in this cohort? Ethicists could dispute incessantly over the ramifications. But ultimately, the decision will be determined by the level of public support, insurers and Type-A surgeons willing to straddle the line between established procedures and experimentation.
Hepatitis is ubiquitous in some pockets of the world. For Taiwan in particular, hepatitis B virus (HBV) infection is hyperendemic. Because HBV is so widespread, there is a severe shortage of organs from donors who do not carry the virus. Thus, one group of physicians utilized hearts from HBV-positive donors.6
Based on their experience, they conclude that although infection with HBV was common (but not universal), it generally responded well to lamivudine. They point out heart transplantation is not contraindicated by HBV carrier status; it simply necessitates close monitoring for potential hepatitis flare-up in patients with HBV antibodies or infection.
Researchers at the Starzl Transplantation Institute had much the same experience; they discovered that a combination drug therapy prevented hepatitis infection in patients who received HBV-infected livers. Twelve patients who received a combination treatment of hepatitis B immune globulin (HBIG) and lamivudine are still HBV-free anywhere between five and 25 months after transplantation. A thirteenth patient -- to whom lamivudine was not yet available -- received only HBIG and developed HBV six months later. The authors concluded that the combination therapy might be able to prevent infection even when the organ is from an HBV-positive donor.7
Other pathogens -- less common, perhaps, but just as damaging in scope -- are varied. Trypanosoma cruzi, a parasite that causes Chagas disease, was found in three organ recipients in 2001. The donor was an immigrant from Central America; in Latin America, Chagas is endemic. All three patients were treated with nifurtimox. Two of the patients died (one of unrelated causes); the other has recovered and has had no recurrence of T. cruzi infection.8
Although there are between 25,000 and 100,000 Latin American immigrants infected with T. cruzi currently in the U.S., there is no policy regarding the screening of potential donors for T. cruzi. Serologic tests for the infection do exist, but they differ in terms of sensitivity and specificity. None of these tests have been licensed in the U.S. for testing organ or blood donors. However, CDC has notified UNOS of the three cases and will consider whether or not screening of potential donors should become standard operating procedure.
Other pathogens that can be transmitted via organ donation include cytomegalovirus, Epstein-Barr virus, toxoplasma and syphilis. 9 Candida has even been a topic of discussion. In Transplantation magazine, one expert was asked if the presence of Candida in a donor's urine is a contraindication to donation. However, the answer is not a simple yes or no; typically, a positive culture for Candida is secondary to colonization, not sepsis or urinary tract infection. But Candida can be transmitted through infected urine. Thus, concludes the expert, it is crucial to verify the origin of the culture, and to remember that there is the potential for a serious Candida infection in the kidney.10