Free-living Acanthamoeba and Naegleria spp. amebae in water sources of León, Nicaragua

free-living amebae (FLA) are known to occur worldwide in water-related biotopes, but only limited information is available on these organisms in developing countries and so far no information on their presence is available from Nicaragua. The aims of this study were to evaluate the prevalence of potentially pathogenic Acanthamoeba spp. and Naegleria spp. in different water sources to which the population of León municipality is exposed. Since pathogenic amebae are thermotolerant, we were especially interested in the occurrence of FLA in geothermal areas. Water samples were collected from León area in Nicaragua: 88 samples were from rivers and springs, 111 from wells, 74 from water taps and 21 from water tanks in urban and suburban León and from three nearby geothermal areas of San Jacinto, Posoltega and Tipitapa. Amebae were identified using morphological and physiological criteria, immunohistochemical staining procedures and molecular methods. Indirect immunofluorescent test was performed on cysts and trophozoites fixed on microscopical slides and incubated for 30 min at room temperature in separate experiments with the following antibodies: rabbit-anti N. fowleri/N. lovanensis (Nf-Pab), mouse monoclonal antibody anti N. fowleri (Nf-5D12u), rabbit antibodies against Acanthamoeba spp. And fluorescent in situ hybridization (FISH) was performed using 18S rRNA-targeted fluorescent oligonucleotide probes. Probes: GSP for the detection of Acanthamoeba and NAEG1088 for the detection of Naegleria. Free-living amebae were recovered from approximately 43 % of the samples. Acanthamoeba spp was found in 21 % of samples from León municipality and in 2 % of samples from geothermal areas. Amoeboflagellates were found in 10 % of samples from León and in 19 % in geothermal areas. Fifty three percent of tested wells in the geothermal area contained thermotolerant amoeboflagellates. Naegleria spp. was identified in 24 out of 39 (61.5 %) of isolated amoeboflagellates. Twelve of them were assigned to N. lovanenesis while none of the isolates could be identified as N. fowleri. However, the common presence of thermotolerant Naegleria in water, specially N. lovanensis, which is an indicator species for N. fowleri, suggests that also this pathogenic amoeba may pose a risk to public health in the area. On the other side, direct pathogenicity, free-living amebae are receiving increasing attention as reservoirs and potential vehicles for the transmission of bacteria in the environment. Thus the information provided in this study may serve as base-line for future studies on the role of free-living amebae e.g. in waterborne-disease outbreaks in the region. Among such potentially important enteropathgens are Vibrio cholerae, E. coli 0157, and Helicobacter pylori. Rev. Biol. Trop. 56 (2): 439-446. Epub 2008 June 30.

Las amebas de vida libre (AVL) son un grupo de organismos de distribución mundial. Entre las AVL hay parásitos facultativos en humanos y otros animales, los cuales pertenecen a los géneros Acanthamoeba, Naegleria y Balamuthia que causan infecciones severas en el sistema nervioso central. Sin embargo no se tiene ninguna información de Nicaragua. El objetivo de este estudio fue evaluar la presencia de amebas de vida libre, en diferentes fuentes de agua de la parte urbana y rural del Departamento de León, y áreas geotérmicas de Nicaragua. Estas amebas fueron identificadas usando criterios morfológicos, fisiológicos, histoquímicos y moleculares. En los resultados se encontró amebas de vida libre en el 43% del total de las muestras. En la municipalidad de León, se encontraron 21% de Acanthamopeba sp. y en las áreas geotérmicas un 2%. Las amebaflagelados tipo Naegleria fueron 10% y 19% respectivamente. Del grupo amebaflagelados fueron 24, de las cuales 12 se dentificaron como N. lovanensis. En estas muestras no se aisló N. fowleri (ameba patógena), sin embargo, la presencia de N. lovanensis es in indicador de la presencia de N. fowleri, la cual puede ser un riesgo a la salud pública. Además, estas amebas pueden servir como vectores de bacterias enteropatógenas.

Soroepidemiology of toxoplasmosis in humans: possible transmission routes in Costa Rica

A serological survey with immunofluorescence techniques to detect toxoplasma antibodies was done on a sample of 1234 Costa Ricans. The overall prevalence was 76 percento; it increased from 60 percento in donors aged 1-4 years to 90 percento in those over 25 years. No significant difference was found in seropositivity between males (42.8 percento) and females (57.2 percento) and between donors from urban and rural (LPI) areas. Consumption of raw meat, especially prepared meat, was significantly correlated with antibody prevalence, but cat contact was not, indicating a possible change in the usual pattern of transmission described for the country. Nevertheless, our data suggest that infectious cat feces play an important role in the transmission of toxoplasmosis

Seroepidemiology of Toxoplasma gondii (Apicomplexa) in meat producing animals in Costa Rica

A serologic screening for Toxoplasma gondii antibodies by IgG indirect fluorescent antibodies test (IgG-IFAT) was carried among 496 swine and 601 cattle serum samples from throughout Costa Rica, to study the possible role of their meat in the transmission of the parasite. The overall prevalence of antibodies was 34.4 per cent in cattle and 43.8 per cent in swine. No significant differences were found in the antibody prevalence between males and females in both animal groups, which acquire the infection early in their lives. Swine did not present significant differences between age groups. In cattle there was a high percent of seropositivity between the first and third years of age. The provinces that showed a greater number of seropositive animals were Limón and Puntarenas for both animals, and Guanacaste for cattle