Immunization of liver and renal transplant recipients: a seroepidemiological and sociodemographic survey.

Several life-threatening infections, a major risk to adult solid organ transplant (SOT) recipients on immunosuppressive therapy, can be prevented by immunization. We analyzed sociodemographic parameters and the immunization status of adult liver transplant recipients (LTX-R, n=267) and renal transplant recipients (RTX-R, n=197) SOT recipients at the Transplantation Center, Berlin, Germany. Date, number, and provider of recommended vaccines were recorded and seroprotection rates determined. The social status in both groups was similar. Most patients (89%) were not adequately informed about immunizations; and if informed, main sources were physicians (47%) and the media (40%). Vaccinations were predominantly provided by family doctors (LTX-R, 66%; RTX-R, 31%) or hemodialysis centers (RTX-R, 37%). Before transplantation, RTX-R had significantly more often received booster vaccinations against tetanus and diphtheria (P<0.005), and a primary hepatitis B immunization (55%); whereas in LTX-R, post-transplant vaccinations against hepatitis A (16%) and pneumococcal disease (13%) were more frequent. Seroprotection rates against tetanus were fairly high in LTX-R (85.3%) and RTX-R (86.8%), and considerably lower for diphtheria, hepatitis A, and influenza. Immunization rates are too low in SOT recipients. Improvement will depend on a more active role of health care providers.

A fast and reliable single-run method for genotyping of the human cytochrome P450 2C8 gene for different ethnic groups.

Patients vary widely in their response to drug therapy according to their genetic background of drug metabolizing enzymes. The cytochrome P450 enzyme CYP2C8 is one of the major metabolizing enzymes involved in drug metabolism and thus a candidate for routine pharmacogenetic screening. The aim of this work was establishing a fast and reliable method to detect the three CYP2C8 genotypes CYP2C8*2, CYP2C8*3, CYP2C8*4, and the wildtype allele. An established real-time polymerase chain reaction (PCR) to detect two CYP2C8 genotypes was extended by introduction of a third hybridization probe. After optimization of running conditions, the new triplex method was evaluated using 200 DNAs of African origin as templates. Standard methods were performed as controls. The new triplex real-time PCR was fast, reliable and reproducible. The obtained results showed no deviation from the results of the established technique. The polymorphism of the CYP2C8 gene among an African population showed the expected distribution (68% wildtype gene, 32% at least one CYP2C8*2 allele). Pharmacogenetics gain increasing interest in routine medical care to prevent severe adverse effects or the application of ineffective drugs. We here provide a fast, reliable and reproducible method in one single assay run to detect three relevant CYP2C8 alleles independent of the patient's ethnic origin.

A syringe exchange programme in prison as prevention strategy against HIV infection and hepatitis B and C in Berlin, Germany.

In two prisons in Berlin, Germany, provision of sterile injection equipment for injecting drug users (IDUs) started in 1998. To assess the programme's impact, the frequency of injecting drug use and syringe sharing, and the incidence of HIV, HBV, and HCV infection were determined in a follow-up study. Of all IDUs (n=174), 75% continued to inject. After the project start the level of syringe sharing declined from 71% during a 4-month period of previous imprisonment to 11% during the first 4 months of follow-up, and to virtually zero thereafter. Baseline seroprevalences for HIV, HBV, and HCV were 18, 53, and 82%. HIV and HCV seroprevalence at baseline was significantly associated with drug injection in prison prior to the project start. No HIV and HBV seroconversions, but four HCV seroconversions occurred. The provision of syringes for IDUs in appropriate prison settings may contribute to a substantial reduction of syringe sharing. However, the prevention of HCV infection requires additional strategies.

Toll-like receptor (TLR) polymorphisms in African children: common TLR-4 variants predispose to severe malaria.

Genetic host factors play a substantial role in susceptibility to and severity of malaria, which continues to cause at least one million deaths per year. Recently, members of the toll-like receptor (TLR) family have been shown to be involved in recognition of the etiologic organism Plasmodium falciparum: The glycosylphosphatidylinisitol anchor induces signaling in host cells via TLR-2 and -4, while hemozoin-induced immune activation involves TLR-9. Binding of microbial ligands to the respective TLRs triggers the release of pro-inflammatory cytokines via the TLR/IL-1 receptor (TIR) domain and may contribute to the host response, including pro-inflammatory cytokine induction and malarial fever. In a case-control study among 870 Ghanaian children, we examined the influence of TLR-2, -4, and -9 polymorphisms in susceptibility to severe malaria. TLR-2 variants common in Caucasians and Asians were completely absent. However, we found a new, rare mutation (Leu658Pro), which impairs signaling via TLR-2. We failed to detect any polymorphisms within the TLR-9/interleukin-1 receptor domain. Two frequent TLR-9 promoter polymorphisms did not show a clear association with malaria severity. In contrast, the TLR-4-Asp299Gly variant occurred at a high rate of 17.6% in healthy controls, and was even more frequent in severe malaria patients (24.1%, p<0.05). Likewise, TLR-4-Thr399Ile was seen in 2.4% of healthy children and in 6.2% of patients (p=0.02). TLR-4-Asp299Gly and TLR-4-Thr399Ile conferred an 1.5- and 2.6-fold increased risk of severe malaria, respectively. These findings suggest TLR4-mediated responses to malaria in vivo and TLR-4 polymorphisms to be associated with disease manifestation. However some gray areas also suggest the scope for further improvements.

Chloroquine-treatment failure in northern Ghana: roles of pfcrt T76 and pfmdr1 Y86.

Although chloroquine (CQ) monotherapy is now generally inadequate for the treatment of Plasmodium falciparum malaria in northern Ghana--recently, 58% of 225 children failed treatment by day 14--use of the drug continues because of its low cost and wide availability. The risk factors associated with CQ-treatment failure in this region of Africa, including the T76 mutation in the chloroquine resistance transporter (pfcrt) gene and the Y86 mutation in the multidrug resistance (pfmdr1) gene of P. falciparum, have now been investigated, and genotype-failure indices (GFI) have been calculated. Treatment failure was found to be associated with young age, poor nutritional status, pfcrt T76 and pfmdr1 Y86, and early treatment failure (ETF) was also associated with high parasitaemia. The presence and concentration of 'residual' CQ in the blood of patients immediately before they were treated with CQ for the present study appeared to have no effect on outcome. Presence at recruitment of pfcrt T76 or pfmdr1 Y86 or both mutations increased the risk of treatment failure by 3.2-, 2.4- and 4.5-fold, and the risk of ETF by 9.8-, 2.7- and 10.2-fold, respectively. The pfcrt T76 GFI for clinical and all treatment failures were 2.8 and 1.4, respectively. These indices were relatively low in the younger children, those with malnutrition, and those with high parasitaemias when treated. Residual CQ did not affect the GFI substantially. Both pfcrt T76 and, to a lesser extent, pfmdr1 Y86 would be useful tools for the surveillance of CQ resistance in northern Ghana. In the current transition phase to alternative first-line treatment for P. falciparum malaria, it should be possible to provide estimates of the level of CQ resistance by monitoring the prevalences of these mutations.

[Infections and diseases after travelling]. / Infektionen und Erkrankungen nach Fernreisen.

BACKGROUND AND OBJECTIVE: With intensifying international travel numbers of travel associated infections and diseases will increase. Systematic studies on infections and diseases with regard to the travel destination in tropical and subtropical areas are scarce in Germany. PATIENTS AND METHODS: Data regarding travel destination, reason, type and duration of travel, symptoms, clinical findings, laboratory results as well as diagnoses of 2024 patients (male 1010, mean age 35 years; female 1014, mean age 33 years) presenting at the outpatient clinic of the Institute of Tropical Medicine Berlin after returning from travel to tropical or subtropical areas were assessed. RESULTS: The most frequent reasons for consultation were diarrhea (33 %), fever (17 %) and skin affections (14 %). A definitive diagnosis was established in 31 % (635). Significant differences were found for prevalences of infectious diseases with regard to travel destinations. 1.5 % of the travellers had contracted malaria. Only 34% of the returnees from malaria-endemic areas had taken chemoprophylaxis; in case of travel to Africa and Asia, chemoprophyplaxis corresponded to international standards in only 48 % and 23%, respectively. Giardia lamblia was the most frequently detected intestinal pathogen. Blastocystis hominis was found to be significantly associated with diarrhea. CONCLUSIONS: Most of the travel-associated infections are self-limited. In case of fever, malaria and potentially hemorrhagic fever should be excluded and be followed by a stepwise investigation on the cause of fever. In case of diarrhea, parasitologic investigations should be performed by an experienced laboratory and fresh stool samples should be used. Intensive co-operation will be necessary between physician, pharmacists and others active in the field of travel medicine in order to address the shortcomings in chemoprophylaxis for malaria. An increasing need for expertise in tropical and travel medicine, especially among private physicians is expected.

Efficacy of chloroquine in the treatment of uncomplicated, Plasmodium falciparum malaria in northern Ghana.

Chloroquine (CQ) resistance in Plasmodium falciparum contributes to growing malaria-attributable morbidity and mortality in sub-Saharan Africa. However, the extent and degree of such resistance vary considerably between endemic areas. Data on CQ resistance in northern Ghana are almost entirely lacking. The therapeutic efficacy of CQ in uncomplicated malaria was therefore assessed, in a standard, 14-day protocol, in 225 children aged <5 years in Tamale, in the Northern region of Ghana. Early treatment failure (ETF) was observed in 11% of the children and late treatment failure in 18%. High initial parasite density and young age were independent predictors for ETF. Resistant parasitological responses (RI-RIII) were seen in 57% of the cases that could be classified. More than half of these responses occurred in children fulfilling the criteria for adequate clinical response (ACR), indicating a considerable lack of agreement between parasitological and clinical outcome. During the follow-up period, haemoglobin levels increased by approximately 1g/dl not only in patients with ACR but also in those who experienced clinical failure more than 1 week post-treatment. As CQ-treatment failure occurred in >25% of the children and more than half of the parasitological responses indicated resistance, current recommendations for the treatment of uncomplicated malaria in young children in northern Ghana have to be reconsidered.

Multiplicity of Plasmodium falciparum infection in pregnancy.

Little is known about the distribution and disease association of multiple Plasmodium falciparum infections in pregnant women. Genotyping of the merozoite surface protein-1 region was performed in 332 P. falciparum infected pregnant women in Ghana, and clinical and epidemiologic data were obtained. Overall, 68% of the women were infected with more than one strain (mean number of strains per carrier = 2.9). The multiplicity of infection decreased significantly with an increasing number of pregnancies, and infection with multiple P. falciparum strains was significantly associated with anemia. In logistic regression, women infected with four or more strains were 2.3 times more likely to be anemic than women harboring fewer strains. This association, however, was only observed in women with up to three pregnancies. The results suggest that with increasing gravidity and subsequent infections with multiple strains effective immune mechanisms against more and more strains develop. In pregnant women, the multiplicity of infection may be an important factor for the acquisition and maintenance of immunity against malaria.

Plasmodium falciparum pfcrt and pfmdr1 polymorphisms are associated with the pfdhfr N108 pyrimethamine-resistance mutation in isolates from Ghana.

The Plasmodium falciparum chloroquine resistance transporter gene (pfcrt) T76 and multidrug resistance gene analogue (pfmdr1) Y86 mutations are associated with chloroquine(CQ)-resistance. In isolates from 172 pregnant women living in the area of Agogo, Ghana, pfcrt T76 was detected in 69% and pfmdr1 Y86 in 66%. Pfcrt T76 but not pfmdr1 Y86 was more prevalent in samples from women with residual CQ in urine or serum. Parasite densities and multiplicity of infection of pfmdr wild type but not of resistant isolates were reduced by CQ. Adjusted for CQ and pyrimethamine (PYR) in urine, the P. falciparum dihydrofolate reductase (pfdhfr) N108 mutation which confers PYR-resistance was 3.1 and 3 times, respectively, more likely to be detected in isolates containing pfcrt and pfmdr1 mutations than in those comprising wild type alleles. Pfcrt, pfmdr, and pfdhfr mutations are frequent in P. falciparum from this part of Ghana which may limit the choice of drugs for the prevention of malaria in pregnancy. The association of CQ- and PYR-resistance mutations independent of recent drug use could indicate accelerated development of resistance to structurally unrelated drugs. Alternatively, it may reflect selection of resistance in persisting infections due to no longer detectable drug pressure.

Andinermals A-C, antiplasmodial constituents from Andira inermis.

Bioassay-guided fractionation of the leaves from Andira inermis was undertaken as part of a screening program to verify the traditional use of herbal remedies against malaria. Among the isolated phenolic compounds three novel 2-arylbenzofuran-3-carbaldehydes, andinermal A-C, were obtained together with a new flavanonol glycoside, taxifolin-3-O-(3"-O-trans-cinnamoyl)-alpha-L-rhamnopyranoside.

Plasmodium falciparum dihydrofolate reductase alleles and pyrimethamine use in pregnant Ghanaian women.

Drug resistance in Plasmodium falciparum affects prevention of malaria in pregnancy. In a cross-sectional study of 530 pregnant Ghanaian women, P. falciparum dihydrofolate reductase (DHFR) gene mutations linked with pyrimethamine resistance were assessed and associations with pyrimethamine intake were analyzed. P. falciparum infected 69% of women without pyrimethamine use, 59% of those who had a history of pyrimethamine consumption but a negative urine test, and 53% of individuals with a positive urine test. Eighty-one percent, 43%, and 74% of the isolates contained the mutations Asn-108, Ile-51, and Arg-59, respectively. Thr-108 occurred in 8%. Pyrimethamine use was associated with increased frequencies of Asn-108 and Arg-59 but not of Ile-51 or Thr-108. In women with prophylaxis, wild-type parasites were absent and anemia tended to be more common with an increasing number of DHFR gene mutations. Pyrimethamine appears to be not adequately effective in this part of Ghana, most likely due to the predominance of resistant parasites. Selection for resistance following insufficient prophylaxis could possibly affect the efficacy of future intermittent sulfadoxine-pyrimethamine treatment.

Atovaquone-proguanil versus mefloquine for malaria prophylaxis in nonimmune travelers: results from a randomized, double-blind study.

Concerns about the tolerability of mefloquine highlight the need for new drugs to prevent malaria. Atovaquone-proguanil (Malarone; GlaxoSmithKline) was safe and effective for prevention of falciparum malaria in lifelong residents of malaria-endemic countries, but experience in nonimmune people is limited. In a randomized, double-blind study, nonimmune travelers received malaria prophylaxis with atovaquone-proguanil (493 subjects) or mefloquine (483 subjects). Information about adverse events (AEs) and potential episodes of malaria was obtained 7, 28, and 60 days after travel. AEs were reported by an equivalent proportion of subjects who had received atovaquone-proguanil or mefloquine (71.4% versus 67.3%; difference, 4.1%; 95% confidence interval, -1.71 to 9.9). Subjects who received atovaquone-proguanil had fewer treatment-related neuropsychiatric AEs (14% versus 29%; P=.001), fewer AEs of moderate or severe intensity (10% versus 19%; P=.001), and fewer AEs that caused prophylaxis to be discontinued (1.2% versus 5.0%; P=.001), compared with subjects who received melfoquine. No confirmed diagnoses of malaria occurred in either group. Atovaquone-proguanil was better tolerated than was mefloquine, and it was similarly effective for malaria prophylaxis in nonimmune travelers.

Short report: increased susceptibility to Plasmodium malariae in pregnant alpha(+)-thalassemic women.

The influence of alpha(+)-thalassemia on malaria in pregnancy was assessed in a cross-sectional study of 530 women in Ghana. Plasmodial infections, alpha(+)-thalassemia, serum levels of C-reactive protein, and antimalarial drugs in urine were determined. The alpha-globin genotypes did not correlate with the prevalence of Plasmodium falciparum-infection and parasite densities. However, Plasmodium malariae tended to be more frequent in alpha(+)-thalassemic women (P = 0.05). Excluding women with residual antimalarials, a significant excess of P. malariae was observed in alpha(+)-thalassemic individuals. Febrile responses (P = 0.05) and inflammation (CRP > 0.6 mg/dl, P = 0.06) appeared to be less common in infected alpha(+)-thalassemic women and were also comparatively rare in parasitemic individuals who harbored double species infections with P. falciparum and P. malariae. Plasmodium malariae may influence the pathogenesis of falciparum malaria leading to a low prevalence of inflammation and febrile responses in alpha(+)-thalassemic women.

Evidence for a reduced effect of chloroquine against Plasmodium falciparum in alpha-thalassaemic children.

Alpha-thalassaemia is common in malaria-endemic regions and is considered to confer protection from clinical disease due to infection with Plasmodium falciparum. In vitro, sensitivity to chloroquine (CQ) of P. falciparum infecting alpha-thalassaemic erythrocytes is reduced. We examined, in a cross-sectional study of 405 Nigerian children, associations between alpha-globin genotypes, blood concentrations of CQ, and P. falciparum parasitaemia. Of the children, 44% were alpha+-thalassaemic (36.8% heterozygous, 7.6% homozygous). CQ in blood and P. falciparum-infection were observed in 52 and 80%, respectively. CQ was more frequently found in homozygous alpha+-thalassaemic (71%) than in non-thalassaemic children (50%; odds ratio, 2.42; 95% confidence interval, 1.01-5.8). Among children with CQ in blood and despite similar drug concentrations, alpha+-thalassaemic individuals had fewer infections below the threshold of microscopy which were detectable by PCR only, and they had a higher prevalence of elevated parasitaemia than non-thalassaemic children. No such differences were discernible among drug-free children. CQ displays a lowered efficacy in the suppression of P. falciparum parasitaemia in alpha+-thalassaemic children; hence protection against malaria due to alpha+-thalassaemia may be obscured in areas of intense CQ usage. Moreover, alpha+-thalassaemia may contribute to the expansion of CQ resistance.

Rapid decline of antibodies after hepatitis A immunization in liver and renal transplant recipients.

BACKGROUND: Hepatitis A vaccine is safe and achieves good seroconversion rates in liver (LTX) and renal (RTX) transplant recipients. METHODS: A study was performed to determine the anti-hepatitis A virus (HAV) antibody decline in LTX and RTX patients, and in healthy controls who have been immunized with two doses of hepatitis A vaccine. RESULTS: LTX and RTX patients had a satisfactory seroconversion rate after complete immunisation. However, 2 years later they had experienced a much more rapid antibody decline than controls, and only 59% of LTX and 26% of RTX seroconverters showed titres above the cut-off level defined as protective. CONCLUSIONS: Patients on immunosuppressive therapy may not be adequately protected against hepatitis A a few years after vaccination and alternative vaccination schemes may have to be considered.

In vitro antiplasmodial activity of 4-phenylcoumarins from Exostema mexicanum.

The stem bark of Exostema mexicanum (Rubiaceae) is used in Latin American folk medicine as a quinine substitute for malaria treatment. Bioassay-guided fractionation of lipophilic and hydrophilic extracts from the stem bark and branches yielded two previously undescribed 4-phenylcoumarins: 4',8-dihydroxy-5,7-dimethoxy-4-phenylcoumarin (exomexin A) and 3',4'-dihydroxy-5,7,8-trimethoxy-4-phenylcoumarin (exomexin B). Together with five known derivatives the in vitro activities against a chloroquine-sensitive strain (poW) and a chloroquine-resistant strain (Dd2) of Plasmodium falciparum have been evaluated. The most lipophilic compound, 4',5,7,8-tetramethoxy-4-phenylcoumarin (O-methylexostemin) revealed the strongest antiplasmodial activity (IC50 values: 3.6 microg/ml [poW], 1.6 microg/ml [Dd2]).

Localized lymphadenopathy due to leishmanial infection.

A 25-year-old female patient presented with an isolated cervical lymph node enlargement several months after having returned from Spain and Latin America. She had no other signs or symptoms of disease. Leishmania infantum/chagasi was identified as the causative agent. With extended travel activities localized lymph node enlargement due to leishmanial infection should be included in the differential diagnosis of lymphadenopathy of unknown origin.

Impact of subpatent multi-species and multi-clonal plasmodial infections on anaemia in children from Nigeria.

Childhood anaemia in sub-Saharan Africa is often caused by Plasmodium falciparum malaria. The influence of subpatent, multi-species and polyclonal infections with malaria parasites on haematological parameters was assessed in 1996/97 in clinically healthy children in Nigeria. Of the 228 children studied, 64% were anaemic by the WHO age-dependent criteria. A univariate analysis of risk factors indicated that the prevalence of anaemia was dependent on the number of Plasmodium species detected by species-specific PCR (P < 0.0001). Furthermore, the prevalence of anaemia increased gradually with the complexity (P < 0.003) as well as with the extent of P. falciparum parasitaemia (P < 0.0001). A logistic regression analysis revealed that individuals with an enlarged spleen tended to be anaemic. The number of Plasmodium species by which an individual was infected was independently associated with anaemia (P < 0.03). ANOVA revealed that the age-corrected values for haemoglobin (Hb) and red blood cells (RBCs) were mainly influenced by the occurrence of mixed infections. Haematological parameters were also influenced by the number of different P. falciparum clones by which an individual was infected. Hb levels and RBC counts were further diminished by additional infections with P. malariae and/or P. ovale. However, the effect of multi-species infections on haematological parameters exceeded that of multi-clonal infections.

Seroepidemiology of TT virus, GBC-C/HGV, and hepatitis viruses B, C, and E among women in a rural area of Tanzania.

The seroprevalence and determinants of hepatitis B, C, and E virus infection, and of GBV-C/hepatitis G virus and TT virus infection were investigated among women from a rural area of northeastern Tanzania. High seroprevalence rates were found for TTV (74%), HBV (74%), and GBV-C/HGV (35%), whereas 7% of the women had evidence of HCV and HEV infection. The majority of TTV DNA sequences in the study population belonged to the genotypes 1 or 2. One sequence seems to represent a new subtype of genotype 4. The GBV-C/HGV sequences either belonged to the genomic Group 1b or to the recently described Group 4. In multivariate analysis, the detection of TTV DNA was associated significantly with a larger number of children in the household and with older age. A history of injections of contraceptive hormones was an independent risk factor for HCV infection. The findings on TTV are consistent with fecal-oral transmission, and recurrent infections may occur in adults.

Antiplasmodial activity of isoflavones from Andira inermis.

The stem bark and seeds of Andira inermis, Fabaceae, are employed as a purgative, vermifuge, and febrifuge. In particular, the powdered bark is claimed to be efficacious in intermittent fever. Bioassay-guided fractionation of lipophilic extracts from the stems and leaves yielded six isoflavones: biochanin A, calycosin, formononetin, genistein, pratensein, and prunetin. Calycosin (3', 7-dihydroxy-4'-methoxyisoflavone) and genistein (4',5, 7-trihydroxyisoflavone) have been shown to possess in vitro activity against the chloroquine-sensitive strain poW and the chloroquine-resistant clone Dd2 of Plasmodium falciparum.