Detection of a knockdown mutation in the voltage-sensitive sodium channel associated with permethrin tolerance in Sarcoptes scabiei var. hominis mites.

BACKGROUND: Increasing evidence has sparked a debate on the loss of sensitivity of scabies mites to conventional permethrin therapy. Mutations in the voltage-sensitive sodium channels (VSSC) were associated with knockdown resistance (kdr) in many arthropods, but have never been identified in Sarcoptes scabiei variatio (var.) hominis mites. OBJECTIVES: To identify factors contributing to therapy failure. METHODS: Sixty-seven mites were collected from 64 scabies-infested patients in Vienna, Austria, of whom 85.9% were refractory to prior permethrin-based treatments, and genotyped for the presence of nucleotide polymorphisms in Domain II of the VSSC, known to be associated with kdr. Information regarding previous antiscabietic therapies, decontamination procedures and possible re-infestations by contacts as well as the response to re-imposed therapies were obtained. RESULTS: Sequence alignment comparisons revealed previously unidentified mutations in the coding region of Domain II of the VSSC. A novel A1663T transversion was detected in 97.0% of the mites, resulting in a non-synonymous substitution from methionine to leucine, M918L, a mutation known to confer kdr in other arthropods. In addition, a synonymous G1659A transition was identified in one mite, which otherwise showed a nucleotide sequence identical to the wild-type reference. No major inconsistencies were observed within the previous therapeutic and decontamination procedures, which could have accounted for the observed non-responsiveness to permethrin-based therapies. Subsequent cure of infestation was achieved in 65.6% of the participants, predominantly by combination therapies with topical permethrin and systemic ivermectin. However, in 14.6% of the cured cases, permethrin monotherapy sufficed for eradication of scabies, albeit in some cases prolonged exposure was necessary. CONCLUSIONS: The kdr-associated M918L mutation in the VSSC gene has now emerged in S. scabiei var. hominis mites. Hence, loss of sensitivity to permethrin due to kdr-type resistance may be more prevalent than anticipated and may be decisive for the therapy responsiveness of scabies-infested patients.

A probabilistic-deterministic approach for assessing climate change effects on infection risks downstream of sewage emissions from CSOs.

The discharge of pathogens into urban recreational water bodies during combined sewer overflows (CSOs) pose a potential threat for public health which may increase in the future due to climate change. Improved methods are needed for predicting the impact of these effects on the microbiological urban river water quality and infection risks during recreational use. The aim of this study was to develop a novel probabilistic-deterministic modelling approach for this purpose building on physically plausible generated future rainfall time series. The approach consists of disaggregation and validation of daily precipitation time series from 21 regional climate models for a reference period (1971-2000, C20), a near-term future period (2021-2050, NTF) and a long-term future period (2071-2100, LTF) into sub-daily scale, and predicting the concentrations of enterococci and Giardia and Cryptosporidium, and infection risks during recreational use in the river downstream of the sewage emissions from CSOs. The approach was tested for an urban river catchment in Austria which is used for recreational activities (i.e. swimming, playing, wading, hand-to-mouth contact). According to a worst-case scenario (i.e. children bathing in the river), the 95th percentile infection risks for Giardia and Cryptosporidium range from 0.08 % in winter to 8 % per person and exposure event in summer for C20. The infection risk increase in the future is up to 0.8 log10 for individual scenarios. The results imply that measures to prevent CSOs may be needed to ensure sustainable water safety. The approach is promising for predicting the effect of climate change on urban water safety requirements and for supporting the selection of sustainable mitigation measures. Future studies should focus on reducing the uncertainty of the predictions at local scale.

[Kala azar - Lethal course of visceral leishmaniasis. Synchronous infection with Leishmania donovani/infantum complex and Leishmania major in a patient after Mediterranean vacation]. / Kala Azar - letaler Verlauf einer viszeralen Leishmaniose. Synchrone Infektion mit Leishmania-donovani/infantum -Komplex und Leishmania major bei einem Patienten nach Mittelmeeraufenthalt.

BACKGROUND: Infections with Leishmania spp. are endemic in areas of the tropics and subtropics. An increased incidence of human infections has been reported in southern Europe, where zoonotic leishmaniasis is common. The systemic, visceral infection is caused by the Leishmania donovani/infantum complex and may be fatal when untreated. PATIENT AND METHODS: A 42-year-old man presented with a 6 week history of erythroderma, pancytopenia, hepatosplenomegaly and recurrent fever after a sojourn in Croatia. The patient's past history revealed a 10-year history of psoriasis and chronic obstructive pulmonary disease treated with methotrexate and prednisolone. Pathology was assessed by histology and molecular biologic analyses. RESULTS AND COURSE: A repeated bone marrow biopsy revealed multiple intracellular particles which were identified as Leishmania amastigotes. Indirect immunofluorescence as well as enzyme-linked immunosorbent assay (ELISA) of patient's serum showed specific anti-Leishmania antibodies. Despite rapid initiation of systemic therapy, the patient died of a secondary infection. Post mortem, PCR and sequencing revealed synchronous infection with Leishmania donovani/infantum complex and Leishmania major. CONCLUSIONS: Diagnosis of patients with complex clinical features is challenging even for experienced clinicians. Critical interpretation of findings and, if necessary, repetition of invasive examinations may be necessary for proper diagnosis. Increasing numbers of immunocompromised patients (iatrogenic, HIV) will expand the spectrum of rare infectious diseases including visceral leishmaniasis.

Granulomatous amebic encephalitis in a child with acute lymphoblastic leukemia successfully treated with multimodal antimicrobial therapy and hyperbaric oxygen.

Acanthamoeba is the causative agent of granulomatous amebic encephalitis, a rare and usually fatal disease. We report a child with acute lymphoblastic leukemia who developed brain abscesses caused by Acanthamoeba during induction therapy. Multimodal antimicrobial chemotherapy and hyperbaric oxygen therapy resulted in complete resolution of symptoms and of pathology as seen by magnetic resonance imaging.

Toxocariasis and the clinical spectrum.

Toxocara canis and T. cati are among the most widely distributed helminthic species in the world with a high zoonotic impact. Millions of people are infecteda and hundreds of thousands are suffering from toxocarosis, a disease encompassing four different entities: larva migrans visceralis (VLM) syndrome, ocular larva migrans (OLM) syndrome, covert toxocarosis (covT), common toxocarosis (comT) and neurotoxocarosis (NT). Toxocara infections in humans may remain clinically inapparent but may also induce severe diseases. This contribution gives a synoptic overview of the most important historical, clinical, diagnostic and therapeutical aspects of toxocarosis in humans.

[Acanthamoeba endophthalmitis-a case report]. / Akanthamöbenendophthalmitis ­ Ein Fallbericht.

Diagnosis of acanthamoeba keratitis is often a clinical challenge. In most cases it is primarily confused with herpes keratitis. A coinfection with bacteria or fungi can also lead to a delayed diagnosis and initiation of treatment. A few cases reported the detection of acanthamoeba in the anterior chamber. In the case of endophthalmitis without the detection of bacteria or fungi acanthamoeba should therefore always be considered as a potential differential diagnosis. The local and systemic administration of voriconazole can be successfully used to treat acanthamoeba endophthalmitis.

Outbreak of microsporidiosis caused by Enterocytozoon bieneusi in falcons.

Four falcons from a private collection of 137 falcons in Abu Dhabi (UAE) died suddenly in summer 2005. In order to screen for a possible disease among the remaining falcons in the aviary, all other birds were caught, examined and treated if necessary. Most of the falcons suffered from massive lice infestation and 74 falcons additionally from a heavy Caryospora sp. burden. Endoscopy revealed yellowish plaques on intestines, livers or kidneys in 70 birds (51.1% morbidity). Proliferative serositis was seen in 17 out of 24 necropsied birds with plaques on intestines, livers or kidneys, which did not resemble any known disease in falcons. However, apart from 20 falcons, which died within a 6-week period after the initial examinations due to advanced disease stages, all other falcons responded well to the treatment with dimetridazole (Emtryl), indicating protozoal disease. Immunohistochemistry confirmed the presence of microsporidial antigen. The final diagnosis of Enterocytozoon (E.) bieneusi genotype D was confirmed with materials from 6 birds by PCR and sequencing. To our knowledge this is the first report of microsporidiosis caused by E. bieneusi in raptors in general and in falcons in particular. However, it is still unclear for how long E. bieneusi was present in the falcon flock, and which role it played in the development of the disease. Predisposing factors such as high temperature and overcrowding in the aviary induced immune suppression causing massive lice infestation as well as coccidiosis, thus paving the way for invasion with microsporidial spores.

Leishmania infections in Austrian soldiers returning from military missions abroad: a cross-sectional study.

OBJECTIVES: The incidence of leishmaniasis is known to increase in conflict areas. The aims of this study were to determine the exposure to Leishmania species in Austrian soldiers returning from missions abroad and to assess possible risk factors. METHODS: A retrospective explorative cross-sectional serologic study was conducted in 225 healthy Austrian soldiers returning from UN or EU peacekeeping missions in Syria, Lebanon and Bosnia and Herzegovina (BIH). Sera were tested for anti-Leishmania antibodies using a commercial enzyme-linked immunosorbent assay. All positive individuals were screened for Leishmania DNA by PCR targeting the ITS1 region using EDTA blood samples. RESULTS: In total, 13.3% (30/225) of the individuals tested were either positive (8%, 18/225) or borderline (5.3%, 12/225) in the enzyme-linked immunosorbent assay, with the highest seroprevalence in soldiers returning from Syria (17.8%, 18/101; 12 positive, six borderline), second from Lebanon (11.1%, 7/63; four positive, three borderline) and lowest from BIH (8.2%, 5/61; two positive, three borderline). Ten soldiers returning from Syria and one from BIH were also positive for Leishmania DNA. Six of these were identified as Leishmania donovani/infantum complex, two as L. tropica and another three as mixed infections by DNA sequencing. Epidemiologic data were collected via a questionnaire, and seropositivity was correlated with a history of insect bites that took a long time to heal (odds ratio, 5.33; 95% confidence interval, 1.23-23.04; p 0.025). CONCLUSIONS: Although pretravel serologic data were not available in this study, the exposure of soldiers to Leishmania spp. during their missions can be assumed to be considerable. Because even asymptomatic infections may resurge in case of emerging immunodeficiencies, adequate prevention measures seem important.

Study on the prevalence of Toxoplasma gondii and Neospora caninum and molecular evidence of Encephalitozoon cuniculi and Encephalitozoon (Septata) intestinalis infections in red foxes (Vulpes vulpes) in rural Ireland.

Thoracic fluid (pleural fluid and clotted blood) from 206 foxes were examined for antibodies to Toxoplasma gondii and 220 thoracic fluid samples were tested for Neospora caninum antibodies using indirect immunofluorescent antibody tests (IFAT). A total of 115 (56%) and six (3%) foxes had antibodies to T. gondii and N. caninum, respectively. The brains from 148 foxes were examined for histological lesions and pathological changes suggestive of parasitic encephalitis were observed in 33 (22%). Two thirds of these foxes had antibodies to T. gondii and one fox had antibodies to both T. gondii and N. caninum. PCR assays carried out on DNA extracted from the 33 brains with histological lesions were negative for N. caninum but one of the brains was positive for T. gondii. Microsporidian DNA was also amplified from the brains of two of these foxes. Sequencing these amplicons revealed 100% homology with Encephalitozoon (Septata) intestinalis in one fox and Encephalitozoon cuniculi in the second fox. This is the first report of Encephalitozoon infections in wildlife in Ireland.

Immunological inter-strain crossreactivity correlated to 18S rDNA sequence types in Acanthamoeba spp.

Various species of the genus Acanthamoeba have been described as potential pathogens; however, differentiation of acanthamoebae remains problematic. The genus has been divided into 12 18S rDNA sequence types, most keratitis causing strains exhibiting sequence type T4. We recently isolated a keratitis causing Acanthamoeba strain showing sequence type T6, but being morphologically identical to a T4 strain. The aim of our study was to find out, whether the 18S rDNA sequence based identification correlates to immunological differentiation. The protein and antigen profiles of the T6 isolate and three reference Acanthamoeba strains were investigated using two sera from Acanthamoeba keratitis patients and one serum from an asymptomatic individual. It was shown, that the T6 strain produces a distinctly different immunological pattern, while patterns within T4 were identical. Affinity purified antibodies were used to further explore immunological cross-reactivity between sequence types. Altogether, the results of our study support the Acanthamoeba 18S rDNA sequence type classification in the investigated strains.

Viability of Acanthamoeba after exposure to a multipurpose disinfecting contact lens solution and two hydrogen peroxide systems.

BACKGROUND/AIM: Contact lens cases contaminated with Acanthamoeba are a major risk factor for an infection of the eye. In this study the anti-Acanthamoeba activity of three different contact lens storage solutions was tested. METHODS: A new multipurpose contact lens storage solution (Meni Care Plus) and a two step (Titmus H(2)O(2)) and one step (Oxysept Comfort) hydrogen peroxide system were tested for their effects on trophozoites and cysts of three different Acanthamoeba species: A castellanii, A hatchetti, and A lenticulata. RESULTS: After a soaking time of 8 hours (overnight soaking of contact lenses) the Titmus H(2)O(2) 0.6% solution showed very good amoebicidal effects, while Oxysept Comfort 3% H(2)O(2) could not effectively destroy the cysts of any of the three tested species. Viable cysts of the species A lenticulata and A hatchetti were still present after exposure to Meni Care Plus (0.0005% PHMB) for 8 hours. CONCLUSION: Not all of the three tested contact lens storage solutions have sufficient amoebicidal effects. The two step peroxide system Titmus H(2)O(2) is a very effective disinfectant contact lens solution in order to avoid a possible Acanthamoeba infection of the eye.

Microwave treatment of contact lens cases contaminated with acanthamoeba.

PURPOSE: Microbially contaminated contact lens cases are a predisposing risk factor for Acanthamoeba keratitis. Several findings have shown that microwave irradiation kills the six Food and Drug Administration test challenge microorganisms. We aimed to determine what effect microwave irradiation has on Acanthamoeba trophozoites and cysts. METHODS: Different types of contact lens cases were contaminated with trophozoites and cysts of three different Acanthamoeba species (A. comandoni, A. castellanii, A. hatchetti) and were exposed to microwave irradiation for 3, 5, and 8 minutes, respectively. RESULTS: Trophozoites, as well as cysts of the different Acanthamoeba strains, were effectively killed, even by only 3 minutes of microwave irradiation, and there were no negative effects of irradiation on the contact lens cases themselves. CONCLUSION: We demonstrate that microwave treatment is a very effective, easy, and cheap method to keep contact lens cases free of Acanthamoeba, thus considerably reducing the risk of an Acanthamoeba keratitis.

Interactions of "Limax amoebae" and gram-negative bacteria: experimental studies and review of current problems.

Free-living amoebae can harbour bacteria inside their cysts giving them a microhabitat and protecting them from disinfectants. The aim of this study was to evaluate the potential importance of "Limax amoebae" as vectors for environmental and nosocomial bacteria in a hospital. It was shown that free-living amoebae are ubiquitous in the investigated hospital, occur syntopically with facultative human pathogens (Comamonas acidovorans and Pseudomonas aeruginosa) and may serve as hosts not only for these but also for bacteria isolated from clinical specimens (Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa); temperature is apparently of crucial importance for the interactions between these microorganisms. Recent studies have shown that "Limax amoebae" apart from acting as protective hosts, may also play a role for the thermotolerance, invasiveness and antibiotic-resistance of bacteria. Considering also the reduced immune-status of many patients, this "symbiosis" of free-living amoebae and bacteria might still be of underestimated hospital-hygienic importance.

Clinical findings and management of imported cutaneous leishmaniasis: report of 14 cases from Austria.

BACKGROUND: The management of cutaneous leishmaniasis in non-endemic countries is challenging due to the wide variety of clinical manifestations and little information available on treatment modalities for travellers. METHODS: Retrospective analysis and follow-up investigation in patients with imported cutaneous leishmaniasis managed at the General Hospital Vienna from 2004 to 2010. RESULTS: In total, 14 patients with cutaneous leishmaniasis were analyzed. The time to diagnosis ranged between weeks and several months and up to four consultations were necessary before diagnosis was accomplished. Histological investigations performed in all patients were diagnostic for CL in 8 (57%) patients. PCR analyses were performed in 12 patients and were positive in 10 (83%) patients. All six patients with negative histological results for CL tested positive in the PCR analysis. Treatment regimens applied included systemic therapy with liposomal amphotericin B, miltefosine, or fluconazole, and local therapy with cryotherapy, paromomycin ointment, photodynamic therapy, surgery, and various combinations. CONCLUSIONS: The present analysis strongly suggests that awareness of CL among physicians and travellers remains low and highlights the need to harmonize diagnostic and treatment guidelines for cutaneous and mucosal leishmaniasis in European travellers. Diagnostic outcome can be improved by combining histology and PCR in patients with suspected cutaneous leishmaniasis.

Seroprevalence and asymptomatic carriage of Leishmania spp. in Austria, a non-endemic European country.

Leishmaniasis is a rare disease in Central Europe and is diagnosed almost exclusively in travellers or migrants coming from tropical or subtropical countries. We conducted an explorative cross-sectional serological study, using a commercial ELISA, in 1048 healthy Austrian individuals to assess the distribution of specific antibodies against Leishmania spp. in humans in Austria. Overall, 47 individuals (4.5%) tested positive, and an additional 32 (3.1%) showed borderline results. After 12 months, sera from 42 of the 79 individuals who had initially tested seropositive/borderline were tested by ELISA a second time: 18 were persistently positive, nine were borderline. Those whose sera were persistently positive/borderline were then screened for potential carrier status using a commercial oligochromatographic PCR test to detect parasite DNA. Four samples were PCR positive and were subjected to a second PCR allowing parasite identification after DNA sequencing: two samples were identified as Leishmania donovani/infantum complex and Leishmania (Viannia) guyanensis, respectively. Epidemiological information was obtained with a questionnaire: no correlation was found for the number of holiday trips within the previous 6 months, but a significant risk of exposure to Leishmania spp. was found for travel to the New World, particularly to the Caribbean. Our data demonstrate that Leishmania spp. seroprevalence in non-endemic countries has been considerably underestimated.

Antiprotozoal compounds: state of the art and new developments.

Protozoa can cause severe diseases, including malaria, leishmaniasis, Chagas disease, sleeping sickness and amoebiasis, all being responsible for morbidity and mortality particularly in tropical countries. To date there are no protective vaccines against any of these diseases, and many of the available drugs are old or elicit serious adverse reactions. Moreover, parasite resistance to existing drugs has become a serious problem. Owing to lack of financial returns, research in this field is of limited interest to pharmaceutical companies and largely depends on funding by public authorities. This article aims to provide a concise overview of the state-of-the-art treatment for the most important tropical protozoal infections as well as new approaches.

In vitro activity of hexadecylphosphocholine (miltefosine) against metronidazole-resistant and -susceptible strains of Trichomonas vaginalis.

OBJECTIVES: Trichomonas vaginalis is the causative agent of trichomoniasis, a sexually transmitted disease with worldwide significance. Trichomoniasis can be treated with metronidazole; however, resistant strains of T. vaginalis have been isolated and there is a lack of useful alternative drugs. The aim of the present study was to examine the activity of hexadecylphosphocholine (HePC; miltefosine), a membrane-active alkylphospholipid, that is licensed as an antileishmanial agent against T. vaginalis. METHODS: The efficacy of HePC after 30 min, 1 h, 16 h and 24 h against four different T. vaginalis strains (with varying resistance to metronidazole) was evaluated. RESULTS: It was shown that all isolates, including the metronidazole-resistant strains, were susceptible to HePC, with EC50s of between 8 and 40 microM and EC90s of between 8 and 80 microM depending on time and on the medium used for the experiments. Treatment of trichomonads with HePC resulted in rounding up and, at concentrations of >or=40 microM, in subsequent total lysis of the organisms. CONCLUSIONS: HePC may be a promising new candidate for the treatment of trichomoniasis.

One- and two-step hydrogen peroxide contact lens disinfection solutions against Acanthamoeba: how effective are they?

PURPOSE: Effective contact lens disinfection solutions are important to keep the storage case free of acanthamoebae and thus prevent an infection of the eye. The aim of our study was to evaluate the effectivity of two new one-step hydrogen peroxide disinfecting solutions against Acanthamoeba spp. and compare it to the effectivity of other commercially available systems. METHODS: Nine one-step 3% hydrogen peroxide systems including the new systems Silver Sept (platinum and silver disk for intensifying disinfection) and Blue Vision (newly composed catalytic tablet) and 2 two-step systems (0.6 and 3.0% H(2)O(2)) were tested for their effectivity against cysts of two Acanthamoeba keratitis isolates at different concentrations. RESULTS: After a soaking time of 8 h (overnight soaking of contact lenses) the 2 two-step systems completely destroyed the cysts of both Acanthamoeba strains, even at the highest concentration of cysts tested. The nine tested one-step systems showed weaker effects. The new Blue Vision system was able to eradicate the cysts of one strain at the low concentration of cysts. CONCLUSIONS: One-step hydrogen peroxide systems do not have sufficient effects on Acanthamoeba cysts and therefore may not protect the contact lens user from a possible infection of the eye. Further development of tablets like the ones used in the Blue Vision system may result in better cysticidal effects for one-step systems.