Warm-region parasites invasion in temperate climate countries.

Encephalitis caused by Free-living amoebae (FLA) has a mortality rate of around 95- 98%, a fraction that has not changed in the past decades. Pathogenic FLA include Acanthamoeba, Balamuthia mandrillaris, and Naegleria fowleri that are known to target the brain after an extra cerebral infection in the case of Acanthamoeba and Balamuthia mandrillaris, or directly the brain, as in the case of the Naegleria fowleri. The Acanthamoeba spp. and Balamuthia mandrillaris cause granulomatous amoebic encephalitis (GAE) while Naegleria fowleri, the so termed "brain eating amoeba" causes primary amoebic meningoencephalitis (PAM). The attempts to obtain a speedy diagnosis and an aggressive treatment protocol are the areas where advances can make a difference and reduce the mortality rates. At first, we highlight the reasons behind the diagnostic delays and treatment failures and provide proposals to establish a quick diagnosis in both PAM and GAE. Secondly, we emphasize the use of a transcribrial device, and a prompt, but vigilant surgical reduction of the intracranial pressure in these patients which could be life-saving. We also debate that an exudate obtained from the olfactory region by irrigation via a modified transcribrial device or by conventional methods, instead of a cerebrospinal fluid sample, could serve as a source of obtaining amoeba in PAM for a real-time polymerase chain reaction-based definitive diagnosis of PAM. Also, introduced is the rationale that has the potential to deliver the drugs to the brain in patients with PAM and the GAE localized to the frontal lobe of the brain, by bypassing the blood brain barrier. We put forward these proposals for debate and deliberation to our fellow colleagues in order to spot the potential of their application to reduce the mortality rates caused by the rare but fatal encephalitis caused by these FLA.

Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri, although free-living amebae, also cause devastating diseases in humans leading to death. Acanthamoeba spp. and B. mandrillaris cause granulomatous amebic encephalitis, cutaneous and nasopharyngeal as well as disseminated infection. Acanthamoeba also causes a vision-threatening infection of the cornea, Acanthamoeba keratitis, principally in contact lens wearers. N. fowleri causes an acute, fulminating infection of the central nervous system, primary amebic meningoencephalitis, in healthy children and young adults who indulge in aquatic activities in fresh water. This review focuses on the recent developments in the diagnosis and treatment and clinical management of the diseases caused by these amebae. Development of a multiplex real-time PCR test has made it possible to simultaneously detect all the three free-living amebae in a sample. It is a rapid assay with a short turn-around time of just 4-5 h. An early diagnosis would be helpful in initiating potentially effective treatment. A recent study reported exciting results indicating that loading of rokitamycin in chitosan microspheres improves and prolongs the in-vitro anti-Acanthamoeba activity of the drug. Diagnoses of these infections are challenging and antimicrobial therapy is empirical, which often results in fatalities. Further research is needed to explore the possibility of a better drug delivery system that crosses the blood-brain barrier and effectively reach the central nervous system.

Risk for Transmission of Naegleria fowleri From Solid Organ Transplantation

Chapter 10 - Infections with free-living amebae

Free-living amoebae (FLA) can be found both in natural aquatic environments and in artificial, man-made aquatic environments. For a long time, (naked) FLA were considered to be harmless protozoa of soil and water. However, research since the 1960s has demonstrated that FLA can be pathogenic to humans and animals with nearly 100% morbidity from some strains. As etiological agents of the so-called Acanthamoebiasis, the Acanthamoebae can trigger several specific diseases (or symptoms) in humans. The amoebiasis of the central nervous system is called granulomatous amebic encephalitis (GAE), when Acanthamoebae are the etiological agents, showing subacute to chronic progress. GAE differs clinically from the primary amoebic meningoencephalitis (PAM(E)), which is caused by Naegleria fowleri. The Acanthamoeba keratitis is not necessarily associated with an immune suppression, but rather with a trauma, exposure to contaminated water or, particularly, the improper handling of contact lenses, which promotes infection. The clinical picture of GAE by Balamuthia mandrillaris is characterized by headache and neck stiffness. The infection is chronic and the time between infection and appearance of neurological symptoms may range from one month to about two years. The prevalence of FLA in water networks is associated with biofilms, where the amoebae live within a biocoenosis sympatric with other microorganisms. These biofilms serve as feeding grounds for the FLA and provide protection to a certain degree while the FLA adhere to the surfaces. In such a biocoenosis there are multiple interactions between FLA and other microorganisms: In addition to their role as pathogens, FLA are known to serve as host of and vehicles for diverse intracellular organisms (bacteria, viruses, eucaryonts), some of them being natural human pathogens. They act as reservoir or vehicle for various microorganisms such as various Legionella sp., Listeria monocytogenes, Pseudomonas aeruginosa and some Mycobacterium sp. In the cyst-stage of the FLA these intracellular organisms (endocytobionts) are protected to a high degree against any adverse environment (FLA as “Trojan horse”). This host-endocytobiont relationship may further lead to health risks in terms of the development of pathogenicity/virulence and antibiotic resistance (FLA as “Trainings ground”).

Pathogenic free-living amoebae (FLA), namely Acanthamoeba sp., Naegleria fowleri and Balamuthia mandrillaris are distributed worldwide. These neurotropic amoebae can cause fatal central nervous system (CNS) infections in humans. This review deals with the demographic characteristics, symptoms, diagnosis, and treatment outcomes of patients with CNS infections caused by FLA documented in India. There have been 42, 25, and 4 case reports of Acanthamoeba granulomatous amoebic encephalitis (GAE), N. fowleri primary amoebic meningoencephalitis (PAM), and B. mandrillaris meningoencephalitis (BAE), respectively. Overall, 17% of Acanthamoeba GAE patients and one of the four BAE patients had some form of immunosuppression, and more than half of the N. fowleri PAM cases had history of exposure to freshwater. Acanthamoeba GAE, PAM, and BAE were most commonly seen in males. Fever, headache, vomiting, seizures, and altered sensorium appear to be common symptoms in these patients. Some patients showed multiple lesions with edema, exudates or hydrocephalus in their brain CT/MRI. The cerebrospinal fluid (CSF) of these patients showed elevated protein and WBC levels. Direct microscopy of CSF was positive for amoebic trophozoites in 69% of Acanthamoeba GAE and 96% of PAM patients. One-fourth of the Acanthamoeba GAE and all the BAE patients were diagnosed only by histopathology following autopsy/biopsy samples. Twenty-one Acanthamoeba GAE survivors were treated with cotrimoxazole, rifampicin, and ketoconazole/amphotericin B, and all eleven PAM survivors were treated with amphotericin B alongside other drugs. A thorough search for these organisms in CNS samples is necessary to develop optimum treatment strategies.

Molecular identification of Acanthamoeba spp., Balamuthia mandrillaris and Naegleria fowleri in soil samples using quantitative real-time PCR assay in Turkey; Hidden danger in the soil!

Brain infection by free-living amoebae can present as granulomatous amoebic encephalitis if caused by Acanthamoeba spp. or Balamuthia mandrillaris, or as primary amoebic meningoencephalitis if caused by Naegleria fowleri, the latter with high morbidity and mortality. Diagnosis is made by studying cerebrospinal fluid or tissue samples by direct microscopy, culture, polymerase chain reaction, or immunofluorescence. There is no specific treatment, and there are only reports of success with prolonged use of combined drugs. We present five cases with a diagnosis of brain infection by free-living amoebae treated at the Hospital Almenara. The patients received surgical treatment, and four of them also received antiparasitic treatment; in one case, the diagnosis was post-mortem. Antiparasitic treatment consisted of a combination of miltefosine, voriconazole, and albendazole mainly, with an average time of 4.8 months. All cases were diagnosed after the initial surgery, and two patients died. Diagnosis in all cases was by direct microscopy, but typing of the free-living amoeba involved was not possible. Brain infection by free-living amoebae is a disease with high morbimortality, which requires early diagnosis for a better prognosis if long-term combined treatment is established.

Balamuthia mandrillaris and Naegleria fowleri are free-living amoebae that causeinfection of the central nervous system, granulomatous amoebic encephalitis(GAE) and primary amoebic meningoencephalitis (PAM), respectively.The fact that mortality rates for cases of GAE and PAM are more than95% indicates the need for new therapeutic agents against those amoebae.Considering that curcumin exhibits a wide range of biological propertiesand has shown efficacy against Acanthamoeba castellanii, we evaluated the amoebicidal properties of curcumin against N. fowleri and B. mandrillaris. Curcumin showed significant amoebicidal activities with an AC50 of 172 and 74 μM against B. mandrillaris and N. fowleri, respectively. Moreover,these compounds were also conjugated with gold nanoparticles to furtherincrease their amoebicidal activities. After conjugation with goldnanoparticles, amoebicidal activities of the drugs were increasedby up to 56 and 37% against B. mandrillaris and N. fowleri, respectively. Thesefindings are remarkable and suggest that clinically available curcuminand our gold-conjugated curcumin nanoparticles hold promise in theimproved treatment of fatal infections caused by brain-eating amoebaeand should serve as a model in the rationale development of therapeuticinterventions against other infections.

Free-living amoebae (FLA) are protozoa widely distributed in the environment, found in a great diversity of terrestrial biomes. Some genera of FLA are linked to human infections. The genus Acanthamoeba is currently classified into 23 genotypes (T1-T23), and of these some (T1, T2, T4, T5, T10, T12, and T18) are known to be capable of causing granulomatous amoebic encephalitis (GAE) mainly in immunocompromised patients while other genotypes (T2, T3, T4, T5, T6, T10, T11, T12, and T15) cause Acanthamoeba keratitis mainly in otherwise healthy patients. Meanwhile, Naegleria fowleri is the causative agent of an acute infection called primary amoebic meningoencephalitis (PAM), while Balamuthia mandrillaris, like some Acanthamoeba genotypes, causes GAE, differing from the latter in the description of numerous cases in patients immunocompetent. Finally, other FLA related to the pathologies mentioned above have been reported; Sappinia sp. is responsible for one case of amoebic encephalitis; Vermamoeba vermiformis has been found in cases of ocular damage, and its extraordinary capacity as endocytobiont for microorganisms of public health importance such as Legionella pneumophila, Bacillus anthracis, and Pseudomonas aeruginosa, among others. This review addressed issues related to epidemiology, updating their geographic distribution and cases reported in recent years for pathogenic FLA.

Saline groundwater desalination has recently emerged as an alternative source of irrigation water in arid and semiarid regions due to the gradual reduction in the quantity and quality of conventional water resources for agricultural use. In Fuerteventura Island (Spain), an extremely arid territory in the European Union, brackish water desalination is one of the few available water sources for agricultural production. Very little research has been conducted on the microbiological quality of this water mainly used for irrigation of vegetable crops. Free-living amoebae (FLA) are widely distributed protozoa in the environment and have been isolated from many environmental sources such as dust, soil and water. Among the pathogenic genera included in this group, Acanthamoeba spp., Naegleria fowleri and Balamuthia mandrillaris have been reported to be causative agents of lethal encephalitis, disseminated infections and keratitis. Particularly, Naegleria fowleri is a pathogenic FLA species which causes primary amoebic meningoencephalitis (PAM). In the present study, the presence of pathogenic FLA strains on desalinated brackish water samples for irrigation has been evaluated during 7months. From the analysed samples, only one was positive for Naegleria australiensis. This is the first report of Naegleria spp. in desalinated brackish water for irrigation in Spain.

Free-Living Amoebas: Is It Safe to Go in the Water?

In 1958, Clyde G. Culbertson predicted the occurrence in humans of infection by free-living amebas (6). A few years later, Rodney F. Carter and Malcolm Fowler, in Adelaide, Australia, reported the first human cases of primary amebic meningoencephalitis (PAM) caused by Naegleria fowleri [2, 91. Since then, hundreds of cases of infection caused by Acanthamoeba spp. and Naegleria fowleri have been published all over the world [20]. During the last 10 years, another opportunistic ameba, B. mandrillaris has been added to the list of pathogenic, opportunistic free-living amebas [ I , 3-5, 7, 8, 10-12, 15-27,

Leońska-Duniec, Agata, Adamska, Małgorzata, Skotarczak, Bogumiła (2015): Molecular Identification of Free-living Amoebae Isolated from Artificial Water Bodies Located in Poland. Acta Protozoologica 54 (1): 77-84, DOI: 10.4467/16890027AP.15.006.2193, URL: https://www.mendeley.com/catalogue/b4f69682-7628-3e01-940b-d34c4617781a/

Three genera of free-living amebae are known human pathogens that cause highly fatal central nervous system (CNS) infections in humans. These are Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri. Acanthamoeba spp. and Balamuthia mandrillaris both cause the highly fatal granulomatous amebic encephalitis (GAE). Naegleria fowleri, also commonly referred to as the brain-eating amoeba, causes primary amebic meningoencephalitis (PAM), which can infect any individual whether immunocompromised or not. Acanthamoeba spp. mostly infect immunocompromised patients, while cases of Balamuthia mandrillaris can infect any individual. Cases of PAM usually occur in children and young adults, and have a high fatality rate. A commonality between all CNS infections from FLA are their propensity to cause fulminant, highly fatal disease that often go undiagnosed or are only identified post-mortem.