Heart transplantation for Chagas cardiomyopathy in the United States.

Since an initial case in 2006, we noted multiple patients undergoing heart transplantation (HTx) for Chagas cardiomyopathy (CC) at our transplant program. The clinical characteristics, laboratory results and outcomes of patients with CC undergoing HTx in the United States have not been reported previously. In 2010, we implemented a systematic screening and management program for patients undergoing HTx for CC. Before HTx, all patients with idiopathic dilated cardiomyopathy who were born in a Chagas disease endemic country were screened for Trypanosoma cruzi (TC) infection with serology. After HTx, monitoring for TC reactivation was performed using clinical visits, echocardiography, endomyocardial biopsy and serial whole blood polymerase chain reaction (PCR) testing. Between June 2006 and January 2012, 11 patients underwent HTx for CC. One patient was empirically treated due to the presence of TC amastigotes in explanted cardiac tissue. Two patients experienced allograft dysfunction due to TC reactivation and three patients experienced subclinical reactivation (positive PCR results), which were treated. Chagas disease is a common cause of dilated cardiomyopathy in patients from endemic countries undergoing HTx at a transplant program in the United States. Reactivation is common after transplantation and can cause adverse outcomes.

Donor-derived Trypanosoma cruzi infection in solid organ recipients in the United States, 2001-2011.

Although Trypanosoma cruzi, the parasite that causes Chagas disease, can be transmitted via organ transplantation, liver and kidney transplantation from infected donors may be feasible. We describe the outcomes of 32 transplant recipients who received organs from 14 T. cruzi seropositive donors in the United States from 2001 to 2011. Transmission was confirmed in 9 recipients from 6 donors, including 3 of 4 (75%) heart transplant recipients, 2 of 10 (20%) liver recipients and 2 of 15 (13%) kidney recipients. Recommended monitoring posttransplant consisted of regular testing by PCR, hemoculture, and serology. Thirteen recipients had no or incomplete monitoring; transmission was confirmed in five of these recipients. Four of the five recipients had symptomatic disease and all four died although death was directly related to Chagas disease in only one. Nineteen recipients had partial or complete monitoring for T. cruzi infection with weekly testing by PCR, hemoculture and serology; transmission was confirmed in 4 of 19 recipients with no cases of symptomatic disease. Our results suggest that liver and kidney transplantation from T. cruzi seropositive donors may be feasible when the recommended monitoring schedule for T. cruzi infection is followed and prompt therapy with benznidazole can be administered.

Application of an improved method for the recombinant k 39 enzyme-linked immunosorbent assay to detect visceral leishmaniasis disease and infection in Bangladesh.

Several serology-based immunoassays are used to diagnose visceral leishmaniasis (VL), a chronic protozoan parasitic disease caused by the Leishmania donovani complex. These tests are primarily designed to diagnose the most severe clinical form of VL, known as kala-azar. However, leishmanial infection is frequently asymptomatic and may manifest only as a positive serologic response or positive leishmanin skin test. We modified a previously described enzyme-linked immunosorbent assay (ELISA) that detects patient antibodies reactive with the recombinant Leishmania protein K39 (rK39) to confirm suspected kala-azar and to detect asymptomatic infection in a community study in Bangladesh. With the inclusion of a standard curve on each ELISA plate, the rK39 ELISA was more repeatable (kappa coefficient of agreement=0.970) and more reliable compared to the original method (kappa=0.587, P<0.001). The cutoff point for a positive antibody response was chosen based on the 99th percentile of the ELISA distribution for the negative-control sera. However, we found that sera from all patients with active kala-azar yielded values more than twice the magnitude of this cutoff. Using receiver-operator characteristic curves, we determined a second cutoff value predictive of kala-azar. Using these criteria, the sensitivity and specificity of the modified ELISA for kala-azar were 97.0% and 98.9%, respectively, for sera from our study population. We hypothesize that individuals with antibody levels greater than the 99th percentile of the negative controls but less than the cutoff point for kala-azar have asymptomatic leishmanial infections.

Transmission of visceral leishmaniasis through blood transfusions from infected English foxhounds to anemic dogs.

OBJECTIVE: To conduct serologic surveillance for Leishmania spp in English foxhounds from a kennel, as well as recipients of blood from these dogs, and determine whether L infantum organisms could be transmitted via blood transfusion. DESIGN: Serologic prevalence survey. ANIMALS: 120 English foxhounds and 51 dogs of various breeds receiving blood from these donors. PROCEDURE: Foxhound blood donors, foxhound nondonors, and nonfoxhound blood recipient dogs were evaluated serologically for Leishmania spp by indirect fluorescent antibody testing. Dogs that received packed RBC (PRBC) transfusions from foxhound donors from mid-1996 through mid-2000 were identified. Furthermore, dogs were serologically evaluated if they had received fresh frozen plasma (FFP) transfusions in 1999 and 2000 from seropositive foxhound blood donors. RESULTS: Thirty percent of the English Foxhounds were seropositive for Leishmania spp (titer > or = 1:16), although the degree of seropositivity varied considerably during the period. Furthermore, 57 foxhounds had been used as donors from 1996 to 2000, and 342 units of PRBC had been transfused to at least 227 patients. All 25 dogs screened that received PRBC from seronegative foxhound donors tested negative, whereas 3 of 7 dogs that received PRBC from seropositive donors tested positive. All 9 dogs that received FFP from seropositive foxhound donors remained seronegative. CONCLUSIONS AND CLINICAL RELEVANCE: To our knowledge, this report documents the first transmission of Leishmania spp by blood transfusion. The use of foxhounds as blood donors may not be advisable in North America.

Use of polymerase chain reaction to diagnose the fifth reported US case of autochthonous transmission of Trypanosoma cruzi, in Tennessee, 1998.

In July 1998, the mother of an 18-month-old boy in rural Tennessee found a triatomine bug in his crib, which she saved because it resembled a bug shown on a television program about insects that prey on mammals. The gut contents of the Triatoma sanguisuga were found, by light microscopy and polymerase chain reaction (PCR), to be infected with Trypanosoma cruzi; PCR products hybridized with T. cruzi-specific oligonucleotide probes. Whole-blood specimens obtained from the child in July and August were negative by buffy-coat examination and hemoculture but positive by PCR and DNA hybridization, suggesting that he had low-level parasitemia. Specimens obtained after treatment with benznidazole were negative. He did not develop anti-T. cruzi antibody; 19 relatives and neighbors also were seronegative. Two of 3 raccoons trapped in the vicinity had positive hemocultures for T. cruzi. The child's case of T. cruzi infection-the fifth reported US autochthonous case-would have been missed without his mother's attentiveness and the availability of sensitive molecular techniques.

Evaluation of Streck tissue fixative, a nonformalin fixative for preservation of stool samples and subsequent parasitologic examination.

We undertook a study to evaluate Streck tissue fixative (STF) as a substitute for formalin and polyvinyl alcohol (PVA) in fecal preservation. A comparison of formalin, PVA, (mercuric chloride based), and STF was done by aliquoting fecal samples into each fixative. Stool specimens were collected in Haiti, and parasites included Cyclospora cayetanensis, Giardia intestinalis, Entamoeba coli, Iodamoeba butschlii, Endolimax nana, Ascaris lumbricoides, Trichuris trichiura, Strongyloides stercoralis, and Necator americanus. Preserved stools were examined at various predetermined times (1 week, 1 month, and 3 months) to establish the quality of the initial preservation as well as the suitability of the fixative for long-term storage. At each time point, stool samples in fixatives were examined microscopically as follows: (i) in wet mounts (with bright-field and epifluorescence microscopy), (ii) in modified acid-fast-, trichrome-, and safranin-stained smears, and (iii) with two commercial test kits. At the time points examined, morphologic features remained comparable for samples fixed with 10% formalin and STF. For comparisons of STF- and 10% formalin-fixed samples, specific findings showed that Cyclospora oocysts retained full fluorescence, modified acid-fast- and safranin-stained smears of Cryptosporidium and Cyclospora oocysts were equal in staining quality, and results were comparable in the immunofluorescence assay and enzyme immunoassay commercial kits. Stool fixed in STF and stained with trichrome showed less-than-acceptable staining quality compared with stool fixed in PVA. STF provides an excellent substitute for formalin as a fixative in routine examination of stool samples for parasites. However, modifications to the trichrome staining procedures will be necessary to improve the staining quality for protozoal cysts fixed in STF to a level comparable to that with PVA.

Evaluation of selected antiprotozoal drugs in the Babesia microti-hamster model.

The presently used therapy for Babesia microti infections, a combination of quinine and clindamycin, does not always result in parasitologic cures. To identify possible alternative chemotherapeutic agents for such infections, we screened, in the hamster-B. microti system, 12 antiprotozoal drugs that have either recently been released for human use or were in experimental stages of development at the Walter Reed Army Institute of Research for the treatment of malaria and leishmaniasis. Several well-recognized antimalarial drugs, such as mefloquine, halofantrine, artesunate, and artelenic acid, exhibited little or no effect on parasitemia. Two 8-aminoquinolines, WR006026 [8-(6-diethylaminohexylamino)-6-methoxy-4-methylquinoline dihydrochloride] and WR238605 [8-[(4-amino-1-methylbutyl)amino]-2,6-dimethoxy-4-methyl-5 -(3-trifluoromethylphenoxy-7) quinoline succinate], produced clearance of patent parasitemia. Furthermore, blood from infected hamsters treated with WR238605 via an intramuscular injection failed to infect naive hamsters on subpassage, thus producing a parasitologic cure. These two compounds merit further screening in other systems and may prove useful in treating human babesiosis.

Survival and infectivity of Babesia in blood maintained at 25 C and 2-4 C.

Babesia microti-infected blood was stored at room temperature (approximately 25 C) or refrigerated (4 C) for 30 days. To assess viability of the parasites after storage at these 2 temperatures, a 0.25-ml aliquot was inoculated into each of 2 hamsters in 2 separate experiments at days 3, 7, 10, 14, 17, 21, 25, and 30. Blood films were prepared and examined weekly for the presence of parasites from all hamsters. Of hamsters inoculated with blood held at room temperature, only those inoculated at day 3 became positive, whereas 4/4 hamsters inoculated with refrigerated blood on day 17 became parasitemic and 1/4 hamsters inoculated with blood held for 21 days became parasitemic. These results indicate that under blood banking conditions, this intracellular protozoan parasite can remain infective and transfusion-acquired infection with this parasite could occur throughout most of the time that blood is normally stored.

Trypanosomes and microfilariae in feral owl and squirrel monkeys maintained in research colonies.

A group of 358 owl and squirrel monkeys imported from Colombia, Peru, and Bolivia for the U.S. Agency for International Development Malaria Vaccine Development Program was examined for trypanosomes and microfilariae. Trypanosoma rangeli, isolated by hemoculture from Aotus nancymai, Saimiri b. boliviensis, and S. b. peruviensis, accounted for 76.6% of all trypanosome infections. Trypanosoma cruzi was isolated from 25 of 194 S. b. boliviensis, including two mixed infections with T. rangeli. Identifications of trypanosomes were confirmed by blinded tests with a panel of five rRNA probes on a subsample of cultures identified morphologically. Although no trypanosomes were isolated from Aotus vociferans or A. lemurinus griseimembra, positive serologic responses to T. cruzi were observed by indirect immunofluorescence assay in all species of monkeys examined and ranged from 42.1% among S. b. peruviensis to 92.3% among A. vociferans. Among T. rangeli-infected monkeys, 43.7% were seronegative for T. cruzi. No microfilariae were found in S. b. boliviensis or A. l. griseimembra. Mansonella barbascalensis and Dipetalonema caudispina were observed in A. vociferans, M. panamensis in A. nancymai, and M. saimiri and D. caudispina in S. b. peruviensis. Such naturally occurring infections in imported animal models are potential sources of accidental transmission to animal handlers and uninfected laboratory animals and can introduce confounding variables into otherwise well-planned and well-executed studies.

Differentiation of trypanosomatid species by hybridization to selected rRNA probes.

Oligonucleotides with sequences complementary to selected regions of the Trypanosoma cruzi large sub-unit ribosomal RNA (rRNA) were used to specifically detect and quantify T. cruzi and other kinetoplastids. By selecting sequences with varying homologies with Crithida fasciculata, another kinetoplastid for which this sequence was known, probes which hybridized to T. cruzi alone or T. cruzi and T. rangeli, various Leishmania species or C. fasciculata were identified. This identification was possible even though the sequences of the large sub-unit (LSU) rRNA of T. rangeli and Leishmania are not known. None of the probes hybridized with rRNA from mouse or human cell lines, and all could quantitatively detect T. cruzi in tissue culture cells. Probing of replicate membranes with these different oligonucleotides allowed discrimination between these species. The functional application of rRNA-specific probes in diagnosis was demonstrated by identification of unknown trypanosomatids in hemocultures of wild-captured owl and squirrel monkeys using a combination of oligonucleotides. Therefore, these probes should be useful in diagnosis and identification of T. cruzi and related parasites.

Endemic visceral leishmaniasis in a dog from Texas.

Visceral leishmaniasis was diagnosed by cytology and positive indirect immunofluorescent antibody titers to Leishmania donovani in a 7-month-old female Basenji dog from Texas. Clinical and laboratory findings included weight loss, hematochezia, hyperglobulinemia, hypoalbuminemia, anemia, and neutrophilic leukocytosis. Evidence of response to treatment with diminazene aceturate and ketoconazole included improvement in the abnormal clinical, hematologic, and biochemical findings, decreased serum globulin concentration and antibody titer to Leishmania donovani, and absence of organisms in examined tissues. Several foci of endemic leishmaniasis have been reported in the United States. Because of its zoonotic potential and the lack of approved treatments for dogs with leishmaniasis in the United States, the development of effective treatment strategies is needed.

The epidemiology of Chagas' disease in a hyperendemic area of Cochabamba, Bolivia: a clinical study including electrocardiography, seroreactivity to Trypanosoma cruzi, xenodiagnosis, and domiciliary triatomine distribution.

A clinicoepidemiologic survey of Chagas' disease was conducted in the remote rural village of Tabacal in southcentral Cochabamba, Bolivia. In June and July 1988, we interviewed and examined 153 of 160 villagers > five years old for signs and symptoms of Chagas' disease. All participants had electrocardiograms (EKGs) and serologic analysis performed, and 20 villagers underwent xenodiagnosis. All 40 houses in the village were examined for triatomes, and house construction materials and defects were recorded. Seventy-four percent of all villagers had serologic evidence of Chagas' disease, and were defined as cases. Cases were three and one-half times more likely to have signs and symptoms of heart failure than non-cases (P = 0.2) and were nine times more likely to have EKG conduction abnormalities than non-cases (P = 0.02). Thirty-three percent of all EKG conduction defects occurred in individuals < 35 years of age. All dwellings had evidence of triatome infestation; 72% of the triatomes collected were positive for metacyclic trypanosomes. We conclude that Trypanosoma cruzi infection is highly prevalent in Tabacal and is a common cause of morbidity in that region.

Prevalence of antibody to Trypanosoma cruzi among blood donors in Los Angeles, California.

Transfusion-associated Chagas' disease is a serious public health problem in Central and South America. With the recent influx of immigrants from Chagas' disease-endemic areas, concern about the risk of disease from blood transfusion has increased in the United States. To assess the prevalence of Trypanosoma cruzi infection in one area, 1024 consecutive blood donations from 988 voluntary blood donors at a medical center in Los Angeles County were screened serologically. The median age of donors screened was 32.5 years; 53.4 percent were male, and 38.4 percent were born in Chagas' disease-endemic countries. All donor sera were tested by complement fixation (CF) and indirect immunofluorescence (IIF) tests. A radioimmunoprecipitation assay (RIPA) was also done on all sera from CF- or IIF-reactive donors and an equal number of sera from nonreactive donors. A second serum specimen was obtained, and interviews were completed for 18 (67%) of 27 donors with an initial CF titer greater than or equal to 8 or an IIF titer greater than or equal to 64. The overall seroreactivity (by CF and IIF) was 1.1 percent (11/988). One donor (0.1%) had antibody specific to the 72- and 90-kDa antigens of T. cruzi on RIPA. Seven recipients of blood components from the seroreactive donors were located and were seronegative at 3 to 6 months. Seroreactive donors were 3.6 times more likely to have been born or to have resided in Mexico or Central America, 8.7 times more likely to have donated blood in the past, and 11.8 times more likely to have a history of malaria prophylaxis or treatment.

Cutaneous leishmaniasis in Guatemala: isoenzyme characterization of isolates from humans.

Leishmania organisms cultivated from cutaneous lesions of humans in Guatemala were characterized by cellulose acetate electrophoresis. Six isolates had electrophoretic enzyme patterns identical to World Health Organization reference strains of Leishmania braziliensis braziliensis, and 5 had patterns identical to reference strains of Leishmania mexicana mexicana.

Epidemiologic study of visceral leishmaniasis in Honduras, 1975-1983.

Between 1975 and 1983, 53 patients with parasitologically proven visceral leishmaniasis (VL) and 16 patients with suspected VL were diagnosed in Honduras. The patients' ages ranged from 3 months to 10 years, but 95% were younger than 3 years old. Since 1978, when 16 patients were reported, the yearly incidence has declined, and in 1982 only 4 patients were reported. We located and interviewed the families of 57 of the 69 patients. At the onset of illness, all 57 patients lived in rural areas, and 55 lived in southern Honduras. All the patients who were discharged from the hospital alive were still living at the time of the interview. A case-control study, using age-matched neighbors as controls, showed that patients were significantly more likely to have lived in poorly constructed, wood-stick houses. We used an indirect immunofluorescence test to analyze blood samples for Leishmania antibodies from 218 family members of patients, 170 family members of controls, and 156 children living on the island of El Tigre, where 4 of the 5 most recently diagnosed patients lived. Although 15 specimens gave a positive reaction to L. donovani antigen, each gave a stronger reaction when tested against Trypanosoma cruzi antigen, suggesting that the reactions to L. donovani were false positives. A serosurvey of 279 dogs of cases and controls and from El Tigre showed that 24 had positive reactions to L. donovani antigen, but only 4 (1.4%) had higher titers to L. donovani than to T. cruzi.(ABSTRACT TRUNCATED AT 250 WORDS)

Human and sylvatic Trypanosoma cruzi infection in California.

In August 1982, a 56-year-old woman from Lake Don Pedro, California, developed acute Chagas' disease (American trypanosomiasis). She had not traveled to areas outside the United States with endemic Chagas' disease, she had never received blood transfusions, and she did not use intravenous drugs. Trypanosoma cruzi cultured from the patient's blood had isoenzyme patterns and growth characteristics similar to T. cruzi belonging to zymodeme Z1. Triatoma protracta (a vector of Trypanosoma cruzi) infected with T. cruzi were found near the patient's home, a trypanosome resembling T. cruzi was cultured from the blood of two of 19 ground squirrels (Spermophilus beecheyi), and six of 10 dogs had antibody to T. cruzi. A serosurvey of three groups of California residents revealed antibody to T. cruzi by complement fixation in six of 237 (2.5 per cent) individuals living near the patient and in 12 of 1,706 (0.7 per cent) individuals living in a community 20 miles northeast of the patient's home, but in only one of 637 (0.2 per cent) blood donors from the San Francisco Bay area. This is the first case of indigenously acquired Chagas' disease reported from California and the first case recognized in the United States since 1955. This investigation suggests that transmission of sylvatic Trypanosoma cruzi infection to humans occurs in California but that Chagas' disease in humans is rare.

Plaque-forming cells in human cord blood: studies on T and B cell function.

Fewer plaque-forming cells (PFC) were found in the cord blood than in adult blood. B cells of newborns seem to be functionally mature. T cells of newborns provide enough help but exert increased suppressor activity.

Complement-enhanced immunity to infection with Neisseria gonorrhoeae in mice.

Subcutaneous chambers were implanted in mice, injected with Neisseria gonorrhoeae, and supplemented with complement as a model for studying the immunogenicity and strain diversity of N. gonorrhoeae. Immunotypic resistance to N. gonorrhoeae in immunized mice was significantly (P less than 0.01) increased by injection of exogenous guinea pig complement into the host before challenge with gonococci. By using this model to test gonococcal isolates from various geographical areas, two highly immunogenic but immunotypically different gonococcal strains were identified. The piliated cells of these strains induced both complement-enhanced immunity and a degree of exogenous complement-independent immunity. The immunity in mice not treated with complement developed more slowly, was less effective, and waned earlier than that which was complement-dependent. Pretreatment with complement, although highly effective in preventing infection in immunized mice, was much less beneficial in terminating already established infections, even though bactericidal antibodies were present at the time of complement treatment. The mouse chamber model in which both complement-mediated and complement-independent mechanisms of protection can be evaluated may provide an additional tool for elucidating the immunology of gonococcal or other microbial infections.

Immunological and serological diversity of Neisseria gonorrhoeae: identification of new immunotypes and highly protective strains.

Gonococci, irrespective of serotype or immunotype, varied significantly in their capacity to induce immunity in animal models, and in vitro serological relatedness did not always insure in vivo cross-protection. By using a serum bactericidal assay followed by in vivo cross-protection studies, new immunotypic strains which were highly protective were identified from cultures isolated in different geographical areas and from patients with various clinical manifestations. Beta-lactamase production and gonococcal immunotype did not appear as related characteristics in that certain penicillin-sensitive strains were highly effective in immunizing animals against infection with beta-lactamase producers. The findings of this study emphasize the importance of using appropriate biological tests and strains for the investigation of gonococcal immunity and vaccine development. Immunization with a combination of a few major gonococcal immunotypic immunogens may provide substantial protection against the majority of penicillin-sensitive and beta-lactamase-producing gonococci. Investigation of isolated immunotypic immunogens is in progress.