Identification of unusual phospholipid fatty acyl compositions of Acanthamoeba castellanii

Acanthamoeba are opportunistic protozoan pathogens that may lead to sight-threatening keratitis and fatal granulomatous encephalitis. The successful prognosis requires early diagnosis and differentiation of pathogenic Acanthamoeba followed by aggressive treatment regimen. The plasma membrane of Acanthamoeba consists of 25% phospholipids (PL). The presence of C20 and, recently reported, 28- and 30-carbon fatty acyl residues is characteristic of amoeba PL. A detailed knowledge about this unusual PL composition could help to differentiate Acanthamoeba from other parasites, e.g. bacteria and develop more efficient treatment strategies. Therefore, the detailed PL composition of Acanthamoeba castellanii was investigated by ³¹P nuclear magnetic resonance spectroscopy, thin-layer chromatography, gas chromatography, high performance liquid chromatography and liquid chromatography-mass spectrometry. Normal and reversed phase liquid chromatography coupled with mass spectrometric detection was used for detailed characterization of the fatty acyl composition of each detected PL. The most abundant fatty acyl residues in each PL class were octadecanoyl (18∶0), octadecenoyl (18∶1 Δ9) and hexadecanoyl (16∶0). However, some selected PLs contained also very long fatty acyl chains: the presence of 28- and 30-carbon fatty acyl residues was confirmed in phosphatidylethanolamine (PE), phosphatidylserine, phosphatidic acid and cardiolipin. The majority of these fatty acyl residues were also identified in PE that resulted in the following composition: 28∶1/20∶2, 30∶2/18∶1, 28∶0/20∶2, 30∶2/20∶4 and 30∶3/20∶3. The PL of amoebae are significantly different in comparison to other cells: we describe here for the first time unusual, very long chain fatty acids with Δ⁵-unsaturation (30∶3^5,21,24) and 30∶2^21,24 localized exclusively in specific phospholipid classes of A. castellanii protozoa that could serve as specific biomarkers for the presence of these microorganisms.

Acanthamoeba polyphaga mimivirus stability in environmental and clinical substrates: implications for virus detection and isolation

Viruses are extremely diverse and abundant and are present in countless environments. Giant viruses of the Megavirales order have emerged as a fascinating research topic for virologists around the world. As evidence of their ubiquity and ecological impact, mimiviruses have been found in multiple environmental samples. However, isolation of these viruses from environmental samples is inefficient, mainly due to methodological limitations and lack of information regarding the interactions between viruses and substrates. In this work, we demonstrate the long-lasting stability of mimivirus in environmental (freshwater and saline water) and hospital (ventilator plastic device tube) substrates, showing the detection of infectious particles after more than 9 months. In addition, an enrichment protocol was implemented that remarkably increased mimivirus detection from all tested substrates, including field tests. Moreover, biological, morphological and genetic tests revealed that the enrichment protocol maintained mimivirus particle integrity. In conclusion, our work demonstrated the stability of APMV in samples of environmental and health interest and proposed a reliable and easy protocol to improve giant virus isolation. The data presented here can guide future giant virus detection and isolation studies.

Emerging trends in free-living amebic infections of the brain: implications for organ transplantation

This epidemiological review analyzed cases of Naegleria fowleri primary amebic meningoencephalitis (PAM) and Balamuthia mandrillaris granulomatous amebic encephalitis (GAE) for behavioral and demographic risk factors for pathogen exposures and potential transmission by organ transplantation. The Centers for Disease Control and Prevention (CDC) Naegleria Workgroup Registry provided 121 cases of laboratory-confirmed PAM over the period, 1937-2007. The CDC and the California Encephalitis Project provided 28 cases of GAE over the period, 1994-2010. There was a statistically significant increase in clusters of PAM cases between the periods, 1937-1996 and 1997-2007. Risk factors for PAM included male gender, freshwater exposures, summer exposures, and exposures in southern-tier US (United States) states. Risk factors for GAE included male gender, exposures in southern-tier US states, Hispanic ethnicity in California, occupational or recreational contacts with soil, and recent organ transplantation. Fatal free-living amebic infections of the brain are increasing today due to more frequent environmental, recreational, and occupational exposures; organ transplantation; and unanticipated clusters of PAM due to N. fowleri inoculations following nasal sinus irrigation using neti pots filled with municipal tap water. Potential organ donors dying from meningoencephalitis of unexplained causes should be screened for free-living amebic infections of the brain capable of hematogenous dissemination in organ recipients.

Evaluation of fixation methods for demonstration of Neoparamoeba perurans infection in Atlantic salmon, Salmo salar L., gills

Formaldehyde-based fixatives are generally employed in histopathology despite some significant disadvantages associated with their usage. Formaldehyde fixes tissue by covalently cross-linking proteins, a process known to mask epitopes which in turn can reduce the intensity of immunohistochemical stains widely used in disease diagnostics. Additionally, formaldehyde fixation greatly limits the ability to recover DNA and mRNA from fixed specimens to the detriment of further downstream molecular analyses. Amoebic gill disease (AGD) has been reliably diagnosed from histological examination of gills although complementary methods such as in situ hybridization (ISH) and polymerase chain reaction (PCR) are required to confirm the presence of Neoparamoeba perurans, the causative agent of AGD. As molecular techniques are becoming more prevalent for pathogen identification, there is a need to adapt specimen collection and preservation so that both histology and molecular biology can be used to diagnose the same sample. This study used a general approach to evaluate five different fixatives for Atlantic salmon, Salmo salar L., gills. Neutral-buffered formalin and seawater Davidson's, formaldehyde-based fixatives commonly used in fish histopathology, were compared to formalin-free commercial fixatives PAXgene®, HistoChoice™MB* and RNAlater™. Each fixative was assessed by a suite of analyses used to demonstrate AGD including routine histochemical stains, immunohistochemical stains, ISH and DNA extraction followed by PCR. All five fixatives were suitable for histological examination of Atlantic salmon gills, with seawater Davidson's providing the best quality histopathology results. Of the fixatives evaluated seawater Davidson's and PAXgene® were shown to be the most compatible with molecular biology techniques. They both provided good DNA recovery, quantity and integrity, from fixed and embedded specimens. The capacity to preserve tissue and cellular morphology in addition to allowing molecular analyses of the same specimens makes seawater Davidson's and PAXgene® appear to be the best fixation methods for diagnosis and research on AGD in Atlantic salmon gills.

Amebic acute appendicitis: systematic review of 174 cases

BACKGROUND

This study aimed to determine the clinical and demographic features of acute amebic appendicitis by reviewing the reported cases.

METHODS

The PubMed and MEDLINE databases were searched to identify articles related to amebic appendicitis using key words. The search included all articles published between 1935 and 2012 without restricting language, journal, or country.

RESULTS

A total of 174 cases of amebic appendicitis reported in 42 articles were analyzed. The mean age of the patients was 23.5 years (range 2 months-83 years). The majority of patients were male (74.0 %), and the majority of cases were reported from countries with high/moderate risk for amebiasis (76.5 %). A history of traveling to a high/moderate-risk country was cited in 64.0 % of the overall cases. The interval between travel and onset of clinical symptoms ranged from months to years. History of or coexisting dysenteric diarrhea was present in only 7.0 and 14.0 % of overall cases, respectively. A preoperative diagnosis of amebiasis was cited for only five cases (3.0 %). Complicated appendicitis was present in 30.7 % of cases, some of which required colon resection. Severe postoperative intraabdominal complications (e.g., liver abscess, abdominal sepsis, gastrointestinal fistula, hemorrhage) occurred in 19.4 % of surgery-treated patients. The overall mortality rate was 3.2 %.

CONCLUSION

Appendectomy specimens should be routinely sent for histopathologic examination. In the case of suspected amebic acute appendicitis, extra precautions-early appendectomy, metronidazole for antibiotic prophylaxis, wet-preparation examination, obtaining a timely pathology result, increasing the awareness of uncommon complications of appendectomy-can hasten appropriate therapeutic intervention and improve outcome.

Comparison of clinical and laboratory characteristics of intestinal amebiasis with shigellosis among patients visiting a large urban diarrheal disease hospital in Bangladesh

Between 1993 and 2011, a total of 371 intestinal amebiasis (IA), caused by Entamoeba histolytica cases were compared with 1,113 shigellosis (randomly selected) patients of icddr,b, excluding co-infections (rotavirus and Vibrio cholerae) in two age stratums: 0-14 years of age and ≥ 15 years of age. The number of IA and shigellosis cases gradually reduced over the study period. In multivariate analysis, individuals 0-14 years of age, slum dwellers (odds ratio [OR] 3.51; 95% confidence interval [CI] 1.69-7.24; P < 0.001), red blood cell (0.44 [0.24-0.86] 0.016), fecal leukocytes (0.17 [0.07-0.33] < 0.001), and alkaline stool (0.16 [0.07-0.36] < 0.001) were independently associated with IA; and among individuals ≥ 15 years of age, living in the slum area (1.88 [1.12-3.14] 0.016), watery stool (2.21 [1.37-3.55] 0.001), use of antimicrobials before visiting hospital (0.67 [0.46-0.99] 0.047), red blood cell (0.45 [0.22-0.94] 0.036), and fecal leukocytes (0.21 [0.12-0.35] < 0.001) in stool were independently associated with IA. Socio-demographic and clinical characteristics of IA and shigellosis varied distantly from each other.

Unde venis? Amebiasis presenting as appendicitis

A returning traveler presenting with fever accompanied by abdominal "pressure" and pain proved to have amebic appendicitis, amebic liver abscess, and probable recent amebic dysentery--a rare combination of findings amply illustrating the value of asking "Unde venis--from where do you come?"

Hepatopleuropulmonary amoebiasis--a case report

Amoebiasis is a food-borne protozoan infection, caused by Entamoeba histolytica. Here a case of hepatopleuropulmonary amoebiasis, which was detected after fibre-optic bronchoscopy is reported. Bronchial aspirate showed trophozoites of Entamoeba histolytica. The patient was treated with tinidazole and responded favourably.

Primary amebic meningoencephalitis in Florida: a case report and epidemiological review of Florida cases

Primary amebic meningoencephalitis (PAM) is a rare but nearly always fatal infection of the central nervous system caused by the thermophilic, free-living ameba Naegleria fowleri. Since its first description in 1965 through 2010, 118 cases have been reported in the U.S.; all cases are related to environmental exposure to warm freshwater; most have occurred in children and adolescents and are associated with recreational water activities, such as swimming, diving, or playing in freshwater lakes, ponds, or rivers. Over one-fourth of all national PAM cases have occurred in Florida. The authors describe here a fatal case of PAM in a resident of northeast Florida and the ensuing environmental and public health investigation; they also provide a review of all cases of PAM in Florida from 1962 to 2010 and discuss public health responses to PAM in Florida, highlighting opportunities for positive collaboration between state and local environmental health specialists, epidemiologists, and the Centers for Disease Control and Prevention.

Successful treatment of granulomatous amoebic encephalitis with combination antimicrobial therapy

Granulomatous amoebic encephalitis (GAE) is a rare but fatal infection. Due to its nonspecific symptoms and laboratory and neuroradiological findings, it is rarely diagnosed antemortem. We herein present the case of a 72-year-old Japanese woman who was diagnosed with GAE following the detection of a pathogen similar to Balamuthia mandrillaris under a microscopic examination of cerebrospinal fluid sediment and who achieved remission with combination antimicrobial therapy. There are no previous reports of pathogens similar to B. mandrillaris being detected in cerebrospinal fluid antemortem; therefore, this case may be used as a benchmark for further studies.

Detection of Neoparamoeba perurans by duplex quantitative Taqman real-time PCR in formalin-fixed, paraffin-embedded Atlantic salmonid gill tissues

The development and the application of a quantitative duplex real-time PCR for the detection of Neoparamoeba perurans and the elongation factor α 1 gene (ELF) of Atlantic salmon, Salmo salar L., and rainbow trout, Oncorhynchus mykiss (Walbaum), are described. A set of primers and probe was designed to amplify a 139-bp fragment specific to the N. perurans 18S rRNA gene. The test was shown to be very sensitive, being able to detect as little as 13.4 DNA copies per μL corresponding to 0.15 fg of template DNA. In addition, the reaction that detected N. perurans was found to have a high degree of repeatability and reproducibility, to have a linear dynamic range (R(2 ) = 0.999) extending over 5 log(10) dilutions and to have a high efficiency (104%). The assay was applied to DNA samples extracted from 48 formalin-fixed, paraffin-embedded (FFPE) salmon gill tissues showing varying degrees of gill histopathology and amoebic gill disease (AGD)-type histopathology ranging from absent to severe (each scored 0-3). Neoparamoeba perurans DNA was detected in all the blocks where AGD-type histopathology was diagnosed microscopically and in 43.6% of the blocks showing signs of gill pathology. The association between parasitic load and gill histopathology and AGD-type histopathology severity was also investigated. This study also describes the development and the application of a second real-time PCR for the generic detection of Neoparamoeba spp., Page, 1987. A set of primers and probe conserved among the Neoparamoeba spp. was designed to amplify a 150-bp fragment within the 18S rRNA gene. Applied to N. perurans-negative gill tissues, the method was used to exclude the presence of other Neoparamoeba spp. in those blocks where gill pathology was observed microscopically.

Evaluation of a rapid point-of-care fecal antigen detection test for Entamoeba histolytica

Amebiasis is a major cause of morbidity and mortality in the developing world. A reliable point-of-care test would help to improve diagnosis and early treatment. We evaluated a novel rapid fecal antigen detection test for E. histolytica (E. HISTOLYTICA QUIK CHEK; TechLab, Inc., Blacksburg, VA), in a cohort of children in Bangladesh where amebiasis is endemic. This point-of-care test had a sensitivity of 100% and a specificity of 100% when compared with enzyme-linked immunosorbent assay antigen detection.

[Role of surgery in the management of pulmonary parasitosis]

Pulmonary parasitosis is scarcely encountered in France, and its diagnosis is quite difficult. If numerous parasites can be responsible for respiratory symptoms, only few of them can develop in the lung parenchyma and lead to complications necessitating a surgical treatment. The most common example is the hydatic disease of the lung. The authors review the biological cycles, clinical forms, diagnostic and treatment principles of those main lung parasites, which deserve surgical consideration.

Entamoeba histolytica pleuropulmonary infection. Case report and review of the literature

Pleuropulmonary amebiasis is the 2nd most common extraintestinal site of amebiasis after liver abscess. We describe a man with pleuropulmonary amebiasis presenting with pulmonary consolidation and pleural effusion. In patients with pneumonia coming from endemic countries such as Lebanon, pleuropulmonary amebiasis should be considered in the setting of chocolate-colored sputum, negative respiratory cultures, and failure of antibacterial therapy.

Acanthamoeba meningoencephalitis presenting as neuropsychiatric lupus in a pediatric patient

We present the case of a 16-year-old patient with systemic lupus erythematosus who presented with altered mental status and regressive behaviour. She was worked up and empirically treated for common and opportunistic infectious agents. All work-up was negative and after an extensive course of antibiotics she was treated for neuropsychiatric lupus with cytoxan. She initially responded, but this was short-lived and she eventually became comatose and passed away. On brain biopsy she was found to have numerous trophozoites with round nucleus, prominent nucleolus and thin nuclear membrane. Methenamine silver stain showed encysted amoeba, corresponding with a diagnosis of acanthamoeba meningoencephalitis. Making the diagnosis of acanthamoeba meningoencephalitis requires a high degree of suspicion. Specific serum antibodies may not be a reliable measure in immunocompromised patients and trophozoites in CSF can be confused with monocytes. Brain biopsy may be required to make a definitive diagnosis. It is important for clinicians treating immunocompromised patients to keep this agent in mind in an immunocompromised patient with neurological manifestations. Acanthamoeba infections have only been reported in a small handful of patients and, to our knowledge, this is the first reported case in the United States.

[Ileocecal ameboma: a case diagnosed by pathology and molecular biology]

Colonic ameboma is a rare benign inflammatory tumor due to the infection by Entamoeba histolytica and poses frequently the problem of colon cancer. We report a case of a 52 year-old patient who presented a cecal amoeboma revealed by a painful mass in the right iliac fossa. Radiologic and endoscopic examinations depicted a parietal thickening of the right colon and the cecum. A presumptive diagnosis of colon cancer was firstly discussed. Confirmation of ameboma was made on pathological examination, PCR and serology.

[Feves and left upper-quadrant abdominal pain in a Tunisian child. Amebic abcess of the spleen]

Amebiasis is a rarely localized in the spleen, and its preoperative diagnosis is difficult. We report the case of an 11-year-old Tunisian girl who presented with fever and left upper-quadrant abdominal pain.

[Amoebae of the genus Acanthamoeba--causative agents of human infections]

Amoebae of the genus Acanthamoeba Volkonsky, 1931 are ubiquitous, amphizoic organisms with a cosmopolitan distribution. Pathogenic strains are the causative agents of a difficult to treat disease, granulomatous amoebic encephalitis (GAE), and skin infections in immunocompromised individuals, and of a painful corneal disease--amoebic keratitis (AK) in immunocompetent individuals. The major portals of entry are the nasopharyngeal mucosa, pulmonary parenchyma, skin lesions (GAE, skin infections), eyes in contact lenses wearers with a history of improper contact lens wear and care, or corneal trauma (AK). Symptoms of the diseases are non-specific and variable which alongside with the lack of awareness among health care professionals often hamper early diagnosis. While treatment options for GAE and skin infections are limited and poorly effective, various antifungals and antimicrobials have proved beneficial in AK, although the therapy is often complicated and long.

Primary amoebic meningo-encephalitis due to Naegleria fowleri

Primary amoebic meningo-encephalitis is a fulminant, often rapidly fatal infection affecting individuals with a recent history of swimming in warm fresh water. A fatal case of primary amoebic meningoencephalitis due to Naegleria fowleri in a 35 years old male suffering from human immunodeficiency virus with pulmonary tuberculosis infection is reported. Naegleria fowleri was diagnosed by wet mount examination of cerebrospinal fluid and the diagnosis was confirmed by culture of the cerebrospinal fluid on non-nutrient agar layered with Escherichia coli. The patient was treated with amphotericin B and antituberculous treatment but the outcome was fatal. Primary amoebic meningo-encephalitis should be suspected in every case of pyogenic meningo-encephalitis in which no bacteria or fungus is found on cerebrospinal fluid examination.

[Perianal cutaneous amebiasis. Report of two cases]

Perianal cutaneous amebiasis is a rare entity, with 0.03% to 0.07% reported incidence. We present two cases of perianal cutaneous amebiasis, both in male patients. Diagnosis was established by biopsy, with demonstration of Entamoeba histolytica trophozoites. Treatment with metronidazol was performed with good outcome. Although incidence of perianal cutaneous amebiasis is low, this entity must be kept in mind when painful atypical ulcers appear in this region. Diagnosis must be confirmed by identification of the parasite and treatment must be established with antiamebic extra-luminal drugs.

Notes from the field: transplant-transmitted Balamuthia mandrillaris --- Arizona, 2010

On August 23, 2010, CDC was notified regarding two organ transplant recipients in Arizona who had encephalitis with multiple ring-enhancing lesions revealed by cerebral magnetic resonance imaging. The common organ donor, a Hispanic male landscaper aged 27 years, had died in Arizona from a presumed stroke on July 21. He had a large skin lesion for approximately 6 months on his back that he had attributed to an insect bite. The ill recipients, a male liver recipient aged 56 years, and a male recipient of a kidney and pancreas aged 24 years, received organ transplants on July 22. In addition, two other recipients received organs from this donor: an adult male heart recipient received his transplant in California on July 22, and an adult male kidney recipient received his transplant in Utah on July 23.

Balamuthia mandrillaris transmitted through organ transplantation --- Mississippi, 2009

On December 14, 2009, a physician in Mississippi contacted CDC to report possible transplant-transmitted encephalitis in two kidney transplant recipients who shared the same organ donor. Histopathologic testing of donor autopsy brain tissue at CDC showed amebae, and subsequent testing of specimens from the donor and the two kidney recipients confirmed transmission by transplantation of Balamuthia granulomatous amebic encephalitis (GAE), a rare disease caused by Balamuthia mandrillaris, a free-living ameba found in soil. One kidney recipient, a woman aged 31 years, died; the other recipient, a man aged 27 years, survived with neurologic sequelae. Recipients of the heart and liver from the same donor received preemptive therapy and have shown no signs of infection. The donor, a previously healthy boy aged 4 years, was presumed to have died from acute disseminated encephalomyelitis (ADEM), an autoimmune neurologic disease, after infection with influenza A. An investigation was conducted by the state health departments in Mississippi, Kentucky, Florida, and Alabama and CDC to characterize the cases, elucidate possible exposures in the donor, and develop recommendations for early detection and prevention. This is the first reported transmission of Balamuthia by organ transplantation. Clinicians should be aware of Balamuthia infection as a potentially fatal cause of encephalitis. Organ procurement organizations (OPOs) and transplant centers should be aware of the potential for Balamuthia infection in donors with encephalitis of uncertain etiology, and OPOs should communicate this elevated risk for infection to transplant centers so they can make an informed risk assessment in the decision to accept an organ.

[Pleuro-pulmonary manifestations disclosing hepatic amoebiasis]

During a mission in ex-Yugoslavia between 2001 and 2004, three French soldiers were sent home because of right pneumopathy, right pleurisy after appendicectomy, haemoptysis and liver haematoma, respectively. They previously were stationed in Africa and/or South America. The initial diagnosis was quickly modified: pleuropulmonary manifestations of amoebic hepatic abscess in two cases, and pleuropulmonary amoebiasis in the last case. The outcome was favourable with standard anti-amoebic treatment. The reports illustrate the possibility of hepatic amoebiasis with local pleuropulmonary manifestations and an exceptional case of pleuropulmonary amoebiasis with hepatobronchial fistula. The authors report this experience because it demonstrates that amoebiasis in European countries remains an often forgotten diagnosis. Although known for a long time in developing countries, amoebiasis in the military or in tourists should be systematically considered.

[Severe infectious keratitis in renal transplant patient: a case report]

Keratitis occurring in renal transplant patients are often severe, with difficult management. We describe the case of a renal transplant patient, 44 year-old man, with history of recurrent herpetic keratitis, which developed an impending corneal perforation. Conjunctival smear showed the presence of amoebic cysts. Anti-amoebic treatment was undertaken in addition with oral aciclovir, and a therapeutic penetrating keratoplasty was performed. An ulceration of the graft occurred within five months. Ocular samples showed the presence of Candida albicans. Despite aggressive antifungal therapy, he required a second therapeutic penetrating keratoplasty for graft perforation. One month later, we noted a recurrence of the ulcer with corneal thinning which evolved to perforation.

[Amebic meningoencephalitis]

It has been reported that amebic meningoencephalitis is caused by some rhizopods, which are taxonomically different from Entamoeba histolytica which is well known as the causative agent of amebic dysentery. Different types of human meningoencephalitis have been reported to be caused by amphizoic amebae, which are not obligatorily parasitic (endozoic) but are usually free-living (exozoic) in nature, i.e., in environmental water and soil: Naegleria fowleri causes acute primary amebic meningoencephalitis (PAM). Acanthamoeba spp. and Balamuthia mandrillaris produce chronic and opportunistic granulomatous amebic (meningo) encephalitis (GAE). Further, most recently, Sappinia diploidea has been identified as an agent that causes comparatively acute type of encephalitis.

[Antigen detection methods in diagnosis of amebiasis, giardiasis and cryptosporidiosis]

Amebiasis is a significant health problem in developing countries. Humans are infected by two morphologically identical species of Entamoeba. Entamoeba histolytica causes amebic colitis and liver abscess, and Entamoeba dispar is noninvasive. Giardia intestinalis infection is seen worldwide and in all age groups. But giardiasis is especially prevalent in countries with poor sanitation and unsafe water, where it's responsible for most cases of childhood diarrhea. Cryptosporidium parvum, a protozoon, is an obligate intracellular parasite which can cause fatal diarrheal disease in immunocompromised individuals. Generally, the diagnosis of human intestinal protozoa depends on microscopic detection. Microscopic detection is inexpensive, but it is very labor-intensive and requires a skilled microscopist. Antigen detection methods (direct fluorescent antibody, enzyme immunoassay, and rapid, dipstick-like tests) can be performed quickly and do not require an experienced and skilled microscopist. Recently, commercially available diagnostic kits for the intestinal parasites E. histolytica, G.intestinalis and Cryptosporidium spp. use the laboratory diagnosis. In this review, we aimed to discuss the diagnosis of these three intestinal parasites using the antigen tests.

Amebic cerebral abscess mimicking bacterial meningitis

We report a case of an amebic brain abscess in a 2-year-old girl, with symptoms mimicking bacterial meningitis with no evidence of disease elsewhere. Histological evaluation of the abscess revealed the organisms, and the abscess regressed in response to specific medical treatment. This article reviews the rarity of these abscesses and difficulty in the diagnosis.

Balamuthia amebic encephalitis--California, 1999-2007

Balamuthia mandrillaris is a free-living ameba that causes encephalitis in humans (both immunocompetent and immunocompromised), horses, dogs, sheep, and nonhuman primates. The ameba is present in soil and likely is transmitted by inhalation of airborne cysts or by direct contamination of a skin lesion. Approximately 150 cases of balamuthiasis have been reported worldwide since recognition of the disease in 1990. Balamuthiasis is difficult to diagnose because 1) the clinical symptoms mimic those of several other types of encephalitis, 2) few laboratories perform appropriate diagnostic testing, and 3) many physicians are unaware of the disease. The lack of recognition and subsequent delay in diagnosis might be a factor in its high mortality. Since 1998, the California Encephalitis Project (CEP) has been testing encephalitis cases for both common and uncommon agents known to cause encephalitis, including Balamuthia. This report describes the 10 balamuthiasis cases identified by CEP during 1999-2007. The preliminary diagnoses in these cases included neurotuberculosis, viral meningoencephalitis, neurocysticercosis, and acute disseminated encephalomyelitis. All but one patient died. These findings underscore the importance of increasing awareness among clinicians, epidemiologists, and public health officials for timely recognition and potential treatment of Balamuthia encephalitis.

Primary amoebic meningoencephalitis due to Naegleria fowleri

Primary amoebic meningoencephalitis (PAM) due to Naegleria fowleri was detected in a 36-year-old, Indian countryman who had a history of taking bath in the village pond. He was admitted in a semi comatosed condition with severe frontal headache, neck stiffness, intermittent fever, nausea, vomiting, left hemiparesis and seizures. Computerized tomography (CT) scan of brain showed a soft tissue non-enhancing mass with erosion of sphenoid sinus. However CSF findings showed no fungal or bacterial pathogen. Trophozoites of Naegleria fowleri were detected in the direct microscopic examination of CSF and these were grown in culture on non-nutrient agar. The patient was put on amphotericin-B, rifampicin and ceftazidime but his condition deteriorated and was taken home by his relatives in a moribund condition against medical advice and subsequently died. A literature review of 7 previous reports of PAM in India is also presented. Four of theses eight cases were non lethal. The mean age was 13.06 years with male: female ratio of 7:1. History of contact with water was present in four cases. Trophozoites could be identified in all 8 cases in this series.

Primary amebic meningoencephalitis--Arizona, Florida, and Texas, 2007

Primary amebic meningoencephalitis (PAM) is a rare but nearly always fatal disease caused by infection with Naegleria fowleri, a thermophilic, free-living ameba found in freshwater environments. Infection results from water containing N. fowleri entering the nose, followed by migration of the amebae to the brain via the olfactory nerve. In 2007, six cases of PAM in the United States were reported to CDC; all six patients died. This report summarizes the investigations of the cases, which occurred in three southern tier states (Arizona, Florida, and Texas) during June-September and presents preliminary results from a review of PAM cases during 1937-2007. Because deaths from PAM often prompt heightened concern about the disease among the public, an updated and consistent approach to N. fowleri risk reduction messages, diagnosis and treatment, case reporting, and environmental sampling is needed.

Fatal disseminated Acanthamoeba lenticulata infection in a heart transplant patient

We report a fatal case of disseminated acanthamebiasis caused by Acanthamoeba lenticulata (genotype T5) in a 39-year-old heart transplant recipient. The diagnosis was based on skin histopathologic results and confirmed by isolation of the ameba from involved skin and molecular analysis of a partial 18S rRNA gene sequence (DF3).

[Probable amebic brain abscess in a homosexual man with an Entamoeba histolytica liver abscess]

A 51-year-old Japanese-Brazilian homosexual man was admitted to a hospital because of fever, headache and right epigastralgia. He had been homosexual for 20 years. An abdominal CT revealed a liver abscess and microscopic examination of the pus of the drainage revealed cystic forms of Entamoeba histolytica. Oral administration of metronidazole 2,250 mg/day was started for amebic liver abscess. He complained of severe throbbing headache, and magnetic resonance imaging (MRI) of the brain showed a brain mass of approximately 2 cm in diameter in the right parietooccipital lobe. An amebic brain abscess was suspected and he was transferred to our hospital. Continuous oral administration of metronidazole for 49 days instead of invasive procedures gradually improved headache, fever and right epigastralgia. On the follow-up MRIs, the brain mass was gradually encapsulated, reduced its size, and finally disappeared. A diagnosis of amebic brain abscess was made on the basis of coexistent amebic liver abscess, MRI findings and a dramatic effectiveness to metronidazole. One should pay attention to E. Histolytica infection in the differential diagnosis of the abscess of the liver and brain since it has been increasing in Japan in recent years.

Acanthamoebae presenting as primary meningoencephalitis in AIDS

A rare case of Acanthamoebae meningoencephalitis is diagnosed in cerebrospinal fluid (CSF) of a 24 years old male suffering from acquired immunodeficiency syndrome (AIDS) patient on the basis of bright field microscopy and culture growth on non-nutrient agar with Escherichia coli. This case illustrates that Acanthamoebae should be considered in the differential diagnosis of meningoencephalitis in AIDS in addition to tuberculosis and cryptococcus infection in tropical areas.

Intensively kept pigs pre-disposed to chlamydial associated conjunctivitis

In the present study, ocular chlamydial infections in pigs that originate from two different farming systems were investigated. In particular, the aim was to test pigs with and without clinical ocular symptoms for the presence of Chlamydiaceae and for linked infections with Acanthamoebae spp. possibly acting as vectors for Chlamydia or Chlamydia-like organisms. In a total of 181 pigs, 102 from Germany (GER), representing the intensively kept animals and 79 from Switzerland (CH), which were kept extensively, were screened for the presence of different pathogens by PCR, including a new Chlamydiaceae-specific intergenic spacer rRNA gene PCR. Additionally, results of clinical examination and cytology were compared between the symptomatic and asymptomatic pigs of the two groups. Ocular symptomatic pigs showed a high prevalence of Chlamydia suis in both groups: CH 79%, GER 90%. Only 23% asymptomatic pigs from CH, but 88% asymptomatic pigs from GER were positive for C. suis by PCR. DNA of Chlamydia-like organisms were detected in 19% CH, but only in 2% GER pigs, whereas only 4% CH and 1% GER pigs were also positive for Acanthamoebae spp. A co-infection of Acanthamoebae spp. and C. suis was present in only 3% of the CH but 28% of the GER pigs. In general, the intensively kept pigs in our study seemed to be pre-disposed to ocular chlamydial infection and associated conjunctivitis. Infections with Chlamydia-like organisms alone and in combination with Acanthamoebae played no role for clinical findings within the tested pig groups, whereas a co-infection of Acanthamoebae and C. suis was able to cause serious ocular manifestations in half of the cases of intensively kept pigs being positive for these microorganisms.

Early diagnosis of amoebic keratitis due to a mixed infection with Acanthamoeba and Hartmannella

A mixed keratitis due to Acanthamoeba and Hartmannella species is reported. The patient was a soft contact lens wearer. Early diagnosis was achieved by polymerase chain reaction and culture. The pathogenic potential of the isolated amoebae was proven using cytotoxicity assays. The reported case underlines the difficulties in identifying a corneal amoebic infection. In our case, the early diagnosis of a mixed infection allowed a proper antiamoebic treatment in an early stage of infection. This may have been the reason of a successful outcome after therapy.