Page 2046 - Hematology_ Basic Principles and Practice ( PDFDrive )

Chapter 120 Transfusion-Transmitted Diseases 1817

neonates. A probable case of platelet transfusion–transmitted L. in the lower two-thirds of the country, but autochthonous vector
donovani was reported in India. A presumed case of transfusion- transmission is rare but has been increasingly reported especially in
transmitted L. mexicana in a renal transplant recipient was mistakenly rural areas of Texas. CDC estimates at least 20 states have had isola-
diagnosed as Chagas disease because of serologic cross-reactivity tion of the insect vector and 17 states with the mammalian reservoir.
between Trypanosoma cruzi and Leishmania. L. infantum DNA was An estimated 300,000 people in the United States and Canada are
amplified from 6% of peripheral blood mononuclear cells of blood estimated to be infected with T. cruzi; most are immigrants from
donors with Leishmania antibodies in the Balearic Islands. Several Latin America. T. cruzi organisms remain viable in whole blood
animal model studies also demonstrate transmission by blood stored at refrigerator temperatures for 18 days, for longer than 8
transfusion. months in citrated blood samples stored at room temperature, and
Asymptomatic infections occur frequently in healthy donors following freezing and thawing. In South America, early data sug-
exposed in endemic areas, and the organisms may circulate in periph- gested that approximately 13% to 49% of recipients of fresh whole
eral blood more than 1 year following exposure. Foxhounds infected blood from parasitemic donors become infected. There has been
with Leishmania species have been found in 18 US states and two concern that additional transfusion-associated Chagas disease cases
Canadian provinces, but transmission has not extended to humans. will occur as immigration increases to the United States from Central
Following reports of L. tropica–related viscerotropic leishmaniasis and South America.
in veterans of Operation Desert Storm, between August 1990 and American trypanosomiasis, or Chagas disease, consists of an acute
December 1992, those serving in that theater of operations were phase that varies from asymptomatic to manifestations that include
deferred from blood donation for 1 year. The deferral period reflected fever, skin rash, and conjunctivitis with edema around the eyelids,
the development of fever, malaise, abdominal pain, and intermittent lymphadenopathy, and hepatosplenomegaly. The acute phase usually
diarrhea up to 7 months after return to the United States. L. tropica resolves in 4 to 8 weeks unless severe myocarditis or meningoencepha-
was found in the bone marrow of seven patients and in the lymph litis intervenes. The latter is associated with fatal outcomes. Intracel-
nodes in one. When intracellular amastigotes were seen in the periph- lular T. cruzi amastigotes remain in cardiac and skeletal muscle
eral blood of the one patient in whom this was studied following following the acute phase. Following an indeterminate stage of
reports of cutaneous and visceral leishmaniasis among troops involved undetermined duration, chronic disease occurs in 20% to 30% of
in the Afghanistan and Iraq wars, a similar 1-year deferral following infected patients, manifesting as cardiac disease (initially conduction
departure from Iraq and Afghanistan was implemented. The military and left ventricular wall abnormalities), megacolon, or achalasia.
continues to enforce lifetime deferral for any clinical history of Diagnosis is made on clinical and serologic grounds most often.
Leishmania infection. Xenodiagnosis, hemoculture, and nucleic acid amplification tests are
The possibility of transmission to humans during military deploy- also available.
ment and travel and the large number of military personnel returning Risk factors for transfusion-transmitted T. cruzi infection include
from Iraq and Afghanistan raise concerns about future transfusion birth or residence in endemic regions such as Central America, South
transmission. To date, there are no cases of transfusion-transmitted America, or Southeastern Mexico; living in dwellings with palm
leishmaniasis in the United States. The widespread use of leukoreduc- leaf–thatched roofs or mud walls, where vector insects reside; oral
tion filters likely has a beneficial role because these filters reduce both intake of contaminated foodstuffs; and receipt of unscreened blood
intracellular and extracellular parasite concentrations by 3 to 4 logs. transfusions in Latin America. Among donors who lived in poor
housing or received a blood transfusion in endemic areas, 3% to 4%
had T. cruzi antibodies. One study, conducted in California in the
Toxoplasmosis 1990s, found that 1 per 340 blood donors had a risk factor for Chagas
disease. A large survey conducted from 1994 to 1998 in Los Angeles
Toxoplasmosis is caused by the obligate intracellular protozoan and Miami among immigrant blood donors from endemic areas
parasite Toxoplasma gondii, whose usual host is the domestic cat. found T. cruzi seroprevalence rates of 1 per 7500 and 1 per 9000,
The parasite is transmitted by exposure to cat feces, by eating raw or respectively. However, none of the 18 recipients in this survey who
undercooked pork, goat, lamb, beef, or wild game, and congenitally. received blood from a seropositive donor, and who were available for
In the NHANES from 1999–2004, 24.8% of foreign-born US testing, had evidence of infection.
residents age 12 to 49 years of age, compared with 8.2% of US–born A look-back study involving blood donations in Mexico made
residents, had serologic evidence of infection; approximately 50% of before determining the donors were T. cruzi–seropositive, found four
those with antibody harbor parasites in tissue. Transfusion-associated of nine recipients of subsequently determined seropositive whole
disease has been described in immunocompromised patients receiv- blood or platelets to be seropositive.
ing granulocyte concentrates from donors with chronic myelocytic Since 1987, 30 years before testing started in the United States
leukemia who would not qualify as blood donors currently. One and Canada, seven cases of transfusion-associated Chagas disease were
possible transfusion-related case involves a platelet transfusion. Red reported in those countries; symptoms developed 2 to 3 months after
cells and frozen plasma transmission have not been reported. transfusion. In six cases, platelets were the implicated component;
and the unit in the seventh case was not identified. In each of the six
cases, the implicated donor emigrated from a T. cruzi–endemic region
Chagas Disease (Bolivia, Mexico, Paraguay, and Chile) between 16 and 33 years
before the implicated donation. T. cruzi may separate with platelets,
The protozoan parasite Trypanosoma cruzi causes Chagas disease. The or room-temperature storage may favor parasite survival. In addition,
infection is widespread in Latin America; approximately 8 to 10 acute Chagas disease has been reported in organ transplant recipients.
million people are affected. Humans become infected when bitten by More recently, two transfusion-related infections were identified in
Trypanosoma cruzi–infected insects of the Reduviidae family (triato- the United States as a result of recipient tracing (look-back) studies
mine, assassin, kissing, or chinch bugs). Congenital transmission (but these represented fewer than 1% of all studied individuals
from mother to fetus, organ transplantation, blood transfusion, and exposed to transfusion of blood from infected donors; see later).
ingestion are recognized routes as well. Once infection occurs, low- Additional transfusion-associated cases have been reported from
level, intermittently detectable parasitemia usually persists for life. Spain, all derived from donors who had emigrated from South
Treatment with benznidazole or nifurtimox can reduce the risk for America for a total of 20 cases ever documented when combining all
chronic sequelae, but neither of these drugs is FDA approved and reported transfusion-associated cases from the United States, Canada
access to only one of these is through an IND with the CDC. and Spain, the countries with the highest immigration rates from
Treatment is most effective during the acute stage of infection. At Latin America. 72
least 18 mammalian species in the United States serve as reservoirs, The assumed increasing prevalence of T. cruzi–infected blood
including armadillos, opossums, and raccoons, and vectors are present donors with immigration into the United States from Latin America,